Chong, C D; Schwedt, T J
White matter damage and brain network alterations in concussed patients: a review of recent diffusion tensor imaging and resting-state functional connectivity data Journal Article
In: Current Pain & Headache Reports, vol. 19, pp. 485, 2015.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Chong2015,
title = {White matter damage and brain network alterations in concussed patients: a review of recent diffusion tensor imaging and resting-state functional connectivity data},
author = {Chong, C D and Schwedt, T J},
year = {2015},
date = {2015-01-01},
journal = {Current Pain \& Headache Reports},
volume = {19},
pages = {485},
address = {Chong,Catherine D. Department of Neurology, Mayo Clinic, 5777 East Mayo Boulevard, Phoenix, AZ, 85054, USA, Chong.catherine@mayo.edu.},
abstract = {Over 2 million people are diagnosed with concussion each year in the USA, resulting in substantial individual and societal burdens. Although 'routine' clinical neuroimaging is useful for the diagnosis of more severe forms of traumatic brain injury, it is insensitive for detecting pathology associated with concussion. Diffusion tensor imaging (DTI) and blood-oxygenation-level-dependent (BOLD) resting-state functional connectivity magnetic resonance imaging (rs-fMRI) are techniques that allow for investigation of brain structural and functional connectivity patterns. DTI and rs-fMRI may be more sensitive than routine neuroimaging for detecting brain sequelae of concussion. This review summarizes recent DTI and rs-fMRI findings of altered structural and functional connectivity patterns in concussed patients.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Murugavel, M; Cubon, V; Putukian, M; Echemendia, R; Cabrera, J; Osherson, D; Dettwiler, A
A longitudinal diffusion tensor imaging study assessing white matter fiber tracts after sports-related concussion Journal Article
In: Journal of Neurotrauma, vol. 31, pp. 1860–1871, 2014.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Murugavel2014,
title = {A longitudinal diffusion tensor imaging study assessing white matter fiber tracts after sports-related concussion},
author = {Murugavel, M and Cubon, V and Putukian, M and Echemendia, R and Cabrera, J and Osherson, D and Dettwiler, A},
year = {2014},
date = {2014-01-01},
journal = {Journal of Neurotrauma},
volume = {31},
pages = {1860--1871},
address = {Murugavel,Murali. 1 Princeton Neuroscience Institute, Princeton University , Princeton New Jersey.},
abstract = {The extent of structural injury in sports-related concussion (SRC) is central to the course of recovery, long-term effects, and the decision to return to play. In the present longitudinal study, we used diffusion tensor imaging (DTI) to assess white matter (WM) fiber tract integrity within 2 days, 2 weeks, and 2 months of concussive injury. Participants were right-handed male varsity contact-sport athletes (20.2+/-1.0 years of age) with a medically diagnosed SRC (no loss of consciousness). They were compared to right-handed male varsity non-contact-sport athletes serving as controls (19.9+/-1.7 years). We found significantly increased radial diffusivity (RD) in concussed athletes (n=12; paired t-test, tract-based spatial statistics; p\<0.025) at 2 days, when compared to the 2-week postinjury time point. The increase was found in a cluster of right hemisphere voxels, spanning the posterior limb of the internal capsule (IC), the retrolenticular part of the IC, the inferior longitudinal fasciculus, the inferior fronto-occipital fasciculus (sagittal stratum), and the anterior thalamic radiation. Post-hoc, univariate, between-group (controls vs. concussed), mixed-effects analysis of the cluster showed significantly higher RD at 2 days (p=0.002), as compared to the controls, with a trend in the same direction at 2 months (p=0.11). Results for fractional anisotropy (FA) in the same cluster showed a similar, but inverted, pattern; FA was decreased at 2 days and at 2 months postinjury, when compared to healthy controls. At 2 weeks postinjury, no statistical differences between concussed and control athletes were found with regard to either RD or FA. These results support the hypothesis of increased RD and reduced FA within 72h postinjury, followed by recovery that may extend beyond 2 weeks. RD appears to be a sensitive measure of concussive injury.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Watts, R; Thomas, A; Filippi, C G; Nickerson, J P; Freeman, K
Potholes and molehills: bias in the diagnostic performance of diffusion-tensor imaging in concussion Journal Article
In: Radiology, vol. 272, pp. 217–223, 2014.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Watts2014,
title = {Potholes and molehills: bias in the diagnostic performance of diffusion-tensor imaging in concussion},
author = {Watts, R and Thomas, A and Filippi, C G and Nickerson, J P and Freeman, K},
year = {2014},
date = {2014-01-01},
journal = {Radiology},
volume = {272},
pages = {217--223},
address = {From the Departments of Radiology (R.W., C.G.F., J.P.N.), Surgery (A.T., K.V.), and Neurology (C.G.F.), University of Vermont, Given Medical Building E301, 89 Beaumont Ave, Burlington, VT 05405.},
abstract = {Purpose To investigate the extent of bias in a clinical study involving "pothole analysis" of diffusion-tensor imaging (DTI) data used to quantify white matter lesion load in diseases with a heterogeneous spatial distribution of pathologic findings, such as mild traumatic brain injury (TBI), and create a mathematical model of the bias. Materials and Methods Use of the same reference population to define normal findings and make comparisons with a patient group introduces bias, which potentially inflates reported diagnostic performance. In this institutional review board-approved prospective observational cohort study, DTI data were obtained in 20 patients admitted to the emergency department with mild TBI and in 16 control subjects. Potholes and molehills were defined as clusters of voxels with fractional anisotropy values more than 2 standard deviations below and above the mean of the corresponding voxels in the reference population, respectively. The number and volume of potholes and molehills in the two groups were compared by using a Mann-Whitney U test. Results Standard analysis showed significantly more potholes in mild TBI than in the control group (102.5 + 34.3 vs 50.6 + 28.9, P \< .001). Repeat analysis by using leave-one-out cross-validation decreased the apparent difference in potholes between groups (mild TBI group, 102.5 + 34.3; control group, 93.4 + 27.2; P = .369). It was demonstrated that even with 100 subjects, this bias can decrease the voxelwise false-positive rate by more than 30% in the control group. Conclusion The pothole approach to neuroimaging data may introduce bias, which can be minimized by independent training and test groups or cross-validation methods. This bias is sufficient to call into question the previously reported diagnostic performance of DTI for mild TBI. RSNA, 2014 Online supplemental material is available for this article.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Lee, R R; Huang, M
Magnetoencephalography in the diagnosis of concussion Journal Article
In: Progress in Neurological Surgery, vol. 28, pp. 94–111, 2014.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Lee2014,
title = {Magnetoencephalography in the diagnosis of concussion},
author = {Lee, R R and Huang, M},
year = {2014},
date = {2014-01-01},
journal = {Progress in Neurological Surgery},
volume = {28},
pages = {94--111},
address = {Department of Radiology, VA San Diego Healthcare System, and University of California, San Diego, San Diego, Calif., USA.},
abstract = {Magnetoencephalography (MEG) is a biomedical technique which measures the magnetic fields emitted by the brain, generated by neuronal activity. Commercial whole-head MEG units have been available for about 15 years, but currently there are only about 20 such units operating in the USA. Here, we review the basic concepts of MEG and list some of the usual clinical indications: noninvasive localization of epileptic spikes and presurgical mapping of eloquent cortex. We then discuss using MEG to diagnose mild traumatic brain injury (mTBI; concussions). Injured brain tissues in TBI patients generate abnormal low-frequency magnetic activity (delta-waves: 1-4 Hz) that can be measured and localized by MEG. These abnormal delta-waves originate from neurons that experience deafferentation from axonal injury to the associated white matter fiber tracts, also manifested on diffusion tensor imaging as reduced fractional anisotropy. Magnetoencephalographic evaluation of abnormal delta-waves (1-4 Hz) is probably the most sensitive objective test to diagnose concussions. An automated MEG low-frequency (slow wave) source imaging method, frequency-domain vector-based spatiotemporal analysis using a L1-minimum norm (VESTAL), achieved a positive finding rate of 87% for diagnosing concussions (blast-induced plus nonblast), 100% for moderate TBI, and no false-positive diagnoses in normal controls. There were also significant correlations between the number of cortical regions generating abnormal slow waves and the total postconcussive symptom scores in TBI patients. 2014 S. Karger AG, Basel.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Acocello, S; Broshek, D K; Saliba, S
Inter-rater and intra-rater reliability of cerebral blood flow measures obtained using the Brain Acoustic Monitor Journal Article
In: Journal of Neuroscience Methods, vol. 221, pp. 85–91, 2014.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Acocello2014,
title = {Inter-rater and intra-rater reliability of cerebral blood flow measures obtained using the Brain Acoustic Monitor},
author = {Acocello, S and Broshek, D K and Saliba, S},
year = {2014},
date = {2014-01-01},
journal = {Journal of Neuroscience Methods},
volume = {221},
pages = {85--91},
address = {University of Virginia, Exercise and Sport Injury Laboratory, 210 Emmet Street South, PO Box 400407, Charlottesville, VA 22901, USA. Electronic address: ss9qb@virginia.edu.},
abstract = {BACKGROUND: Current assessment of sport-related concussion involves a multifaceted approach including neurocognitive testing, symptom report, and balance assessment. Lacking from this paradigm is a truly objective measure of the physiological changes associated with concussion. NEW METHOD: A device called the Brain Acoustic Monitor (BAM) has been developed to detect cerebral blood flow changes resulting from traumatic brain injury by amplification and comparison of sound waves created by cerebral arteries and a reference artery. The reliability of its measures is unknown, limiting its use in day-to-day assessment of concussion. Therefore, the purpose of this study was to determine the inter- and intra-rater reliability associated with BAM measures. Twenty healthy participants were assessed on two occasions, separated by at least 24h. Ten subjects were measured during the initial session by two assessors for inter-rater comparisons. Measures of positive-to-negative signal deflection (ratio) and frequency divergence from a reference arterial signal (divergence) were calculated and analyzed using Intra-class correlations (2,1). RESULTS: Inter-rater reliability ranged from poor to excellent, showing greater reliability in right brain vs. left brain measures. Intra-rater reliability was similar with a range of poor to good. COMPARISON WITH EXISTING METHODS: These findings are comparable to the reliability of current methods of concussion assessment, specifically neurocognitive testing. CONCLUSION: All BAM values obtained in our healthy subjects were well below scores that would reflect potential head injury. These findings emphasize the potential usefulness of this device in future research concerning serial measurement of cerebral perfusion pressure changes associated with sport concussion.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Johnson, B; Zhang, K; Gay, M; Neuberger, T; Horovitz, S; Hallett, M; Sebastianelli, W; Slobounov, S
Metabolic alterations in corpus callosum may compromise brain functional connectivity in MTBI patients: An H-1-MRS study Journal Article
In: Neuroscience Letters, vol. 509, pp. 5–8, 2012, ISSN: 0304-3940.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Johnson2012b,
title = {Metabolic alterations in corpus callosum may compromise brain functional connectivity in MTBI patients: An H-1-MRS study},
author = {Johnson, B and Zhang, K and Gay, M and Neuberger, T and Horovitz, S and Hallett, M and Sebastianelli, W and Slobounov, S},
doi = {10.1016/j.neulet.2011.11.013},
issn = {0304-3940},
year = {2012},
date = {2012-01-01},
journal = {Neuroscience Letters},
volume = {509},
pages = {5--8},
abstract = {After clinical resolution of signs and symptoms of mild traumatic brain injury (MTBI) it is still not clear if there are residual abnormalities of structural or functional brain networks. We have previously documented disrupted interhemispheric functional connectivity in 'asymptomatic' concussed individuals during the sub-acute phase of injury. Testing of 15 normal volunteers (NV) and 15 subacute MTBI subjects was performed within 24 h of clinical symptoms resolution and medical clearance for the first stage of aerobic activity. In this MRS study we report: (a) both in the genu and splenium of the corpus callosum NAA/Cho and NAA/Cr ratios were significantly (p \< 0.05) lower in MTBI subjects shortly after the injury compared to NVs, and (b) the metabolic ratio NAA/Cho in the splenium significantly correlated with the magnitude of inter-hippocampal functional connectivity in normal volunteers, but not in MTBI. This novel finding supports our hypothesis that the functional disruption of interhemispheric brain networks in MTBI subjects results from compromised metabolic integrity of the corpus callosum and that this persists despite apparent clinical return to baseline.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Lin, A P; Liao, H J; Merugumala, S K; Prabhu, S P; Meehan, W P; Ross, B D
Metabolic imaging of mild traumatic brain injury Journal Article
In: Brain Imaging and Behavior, vol. 6, pp. 208–223, 2012.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Lin2012,
title = {Metabolic imaging of mild traumatic brain injury},
author = {Lin, A P and Liao, H J and Merugumala, S K and Prabhu, S P and Meehan, W P and Ross, B D},
doi = {10.1007/s11682-012-9181-4},
year = {2012},
date = {2012-01-01},
journal = {Brain Imaging and Behavior},
volume = {6},
pages = {208--223},
abstract = {Traumatic brain injury results in a metabolic cascade of changes that occur at the molecular level, invisible to conventional imaging methods such as computed tomography or magnetic resonance imaging. Non-invasive metabolic imaging tools such as single photon emission computed tomography (SPECT), positron emission tomography (PET), and magnetic resonance spectroscopy (MRS) are the ideal methods for providing insight to these changes by measuring regional cerebral blood flow, glucose metabolism, and brain metabolite concentrations, respectively, after mild traumatic brain injury (mTBI). The purpose of this review is to provide an overview of the different methodologies and provide an up-to-date summary of recent findings with SPECT, PET, and MRS technologies, specifically after mTBI, as defined by standardized criteria. Given that the different physiological and pathological responses are heterogeneous, efforts will be made to separate studies at different time points after injury (acute, subacute, and chronic stages) as well as to the different types of mTBI such sports-related head injury where repetitive head injuries are much more common and may present a unique signature.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Tang, L; Ge, Y L; Sodickson, D K; Miles, L; Zhou, Y X; Reaume, J; Grossman, R I
Thalamic resting-state functional networks: Disruption in patients with mild traumatic brain injury Journal Article
In: Radiology, vol. 260, pp. 831–840, 2011, ISSN: 0033-8419.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Tang2011,
title = {Thalamic resting-state functional networks: Disruption in patients with mild traumatic brain injury},
author = {Tang, L and Ge, Y L and Sodickson, D K and Miles, L and Zhou, Y X and Reaume, J and Grossman, R I},
doi = {10.1148/radiol.11110014},
issn = {0033-8419},
year = {2011},
date = {2011-01-01},
journal = {Radiology},
volume = {260},
pages = {831--840},
abstract = {Purpose: To explore the neural correlates of the thalamus by using resting-state functional magnetic resonance (MR) imaging and to investigate whether thalamic resting-state networks (RSNs) are disrupted in patients with mild traumatic brain injury (MTBI). Materials and Methods: This HIPAA-compliant study was approved by the institutional review board, and written informed consent was obtained from 24 patients with MTBI and 17 healthy control subjects. The patients had varying degrees of symptoms, with a mean disease duration of 22 days. The resting-state functional MR imaging data were analyzed by using a standard seed-based whole-brain correlation method to characterize thalamic RSNs. Student t tests were used to perform comparisons. The association between thalamic RSNs and performance on neuropsychologic and neurobehavioral measures was also investigated in patients with MTBI by using Spearman rank correlation. Results: A normal pattern of thalamic RSNs was demonstrated in healthy subjects. This pattern was characterized as representing relatively symmetric and restrictive functional thalamocortical connectivity, suggesting an inhibitory property of the thalamic neurons during the resting state. This pattern was disrupted, with significantly increased thalamic RSNs (P \<= .005) and decreased symmetry (P = .03) in patients with MTBI compared with healthy control subjects. Increased functional thalamocortical redistributive connectivity was correlated with diminished neurocognitive functions and clinical symptoms in patients with MTBI. Conclusion: These findings of abnormal thalamic RSNs lend further support to the presumed subtle thalamic injury in patients with MTBI. Resting-state functional MR imaging can be used as an additional imaging modality for detection of thalamocortical connectivity abnormalities and for better understanding of the complex persistent postconcussive syndrome. (C) RSNA, 2011},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Unden, Johan; Romner, Bertil
Can low serum levels of S100B predict normal CT findings after minor head injury in adults?: an evidence-based review and meta-analysis Journal Article
In: Journal of Head Trauma Rehabilitation, vol. 25, pp. 228–240, 2010.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Unden2010,
title = {Can low serum levels of S100B predict normal CT findings after minor head injury in adults?: an evidence-based review and meta-analysis},
author = {Unden, Johan and Romner, Bertil},
year = {2010},
date = {2010-01-01},
journal = {Journal of Head Trauma Rehabilitation},
volume = {25},
pages = {228--240},
address = {Department of Anaesthesia and Intensive Care, Halmstad Regional Hospital, Halmstad, Sweden. johan.unden@Ithalland.se},
abstract = {OBJECTIVE: To determine whether low levels of S100B in serum can predict normal computed tomography (CT) findings after minor head injury (MHI) in adults. PARTICIPANTS: Not applicable. DESIGN: Systematic evidence-based review of the peer-reviewed literature with meta-analytical interpretation. PRIMARY MEASURES: Not applicable. RESULTS: We identified 12 eligible articles that specifically studied adult MHI patients with S100B and cranial CT scans in the acute phase after injury, comprising a total of 2466 separate patients. Individual negative predictive values of 90% to 100% were found for the ability of a negative (under cutoff) S100B level to predict a normal CT scan. A total of 6 patients included in the studies had low S100B levels and positive CT scans (0.26%) and only 1 of these patients (0.04%) had a clinically relevant CT finding. The pooled negative predictive value for all studies was more than 99% (95% CI 98%-100%), with an average prevalence for any CT finding at 8%. The studies are consistently classed as level 2 and level 3 grades of evidence, suggesting a grade B recommendation. CONCLUSION: Low serum S100B levels accurately predict normal CT findings after MHI in adults. S100B sampling should be considered in MHI patients with no focal neurological deficit, an absence of significant extracerebral injury, should be taken within 3 hours of injury, and the cutoff for omitting CT set at less than 0.10 microg/L. Care givers should also be aware of other clinical factors predictive of intracranial complications after MHI.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Wu, Trevor C; Wilde, Elisabeth A; Bigler, Erin D; Yallampalli, Ragini; McCauley, Stephen R; Troyanskaya, Maya; Chu, Zili; Li, Xiaoqi; Hanten, Gerri; Hunter, Jill V; Levin, Harvey S
Evaluating the relationship between memory functioning and cingulum bundles in acute mild traumatic brain injury using diffusion tensor imaging Journal Article
In: Journal of Neurotrauma, vol. 27, pp. 303–307, 2010.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Wu2010,
title = {Evaluating the relationship between memory functioning and cingulum bundles in acute mild traumatic brain injury using diffusion tensor imaging},
author = {Wu, Trevor C and Wilde, Elisabeth A and Bigler, Erin D and Yallampalli, Ragini and McCauley, Stephen R and Troyanskaya, Maya and Chu, Zili and Li, Xiaoqi and Hanten, Gerri and Hunter, Jill V and Levin, Harvey S},
year = {2010},
date = {2010-01-01},
journal = {Journal of Neurotrauma},
volume = {27},
pages = {303--307},
address = {Department of Psychology, Brigham Young University, Provo, Utah, USA.},
abstract = {Compromised memory functioning is one of the commonly reported cognitive sequelae seen following mild traumatic brain injury (mTBI). Diffusion tensor imaging (DTI) has been shown to be sufficiently sensitive at detecting early microstructural pathological alterations after mTBI. Given its location and shape, the cingulate, which is comprised of the cingulate gyrus (gray matter) and cingulum bundles (white matter), is selectively vulnerable to mTBI. In this study we examined the integrity of cingulum bundles using DTI, and the relationship between cingulum bundles and memory functioning. Twelve adolescents with mTBI and 11 demographically-matched healthy controls were studied. All participants with mTBI had a Glasgow Coma Scale score of 15, and were without intracranial findings on CT scan. Brain scans were performed on average 2.92 days post-injury, and all participants were administered the Verbal Selective Reminding Test (VSRT), an episodic verbal learning and memory task. Participants with mTBI had a significantly lower apparent diffusion coefficient (ADC) bilaterally than controls (p \< 0.001). Despite the marginal significance of the group difference in fractional anisotropy (FA), the effect size between groups was moderate (d = 0.66). Cognitively, healthy controls performed better than the TBI group on immediate and delayed recall; however, the difference did not reach statistical significance. In the mTBI group, FA of the left cingulum bundle was significantly correlated with 30-min delayed recall (r = -0.56},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Stulemeijer, M; Vos, P E; van der Werf, S; van Dijk, G; Rijpkema, M; Fernandez, G
How mild traumatic brain injury may affect declarative memory performance in the post-acute stage Journal Article
In: Journal of Neurotrauma, vol. 27, pp. 1585–1595, 2010, ISSN: 0897-7151.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Stulemeijer2010,
title = {How mild traumatic brain injury may affect declarative memory performance in the post-acute stage},
author = {Stulemeijer, M and Vos, P E and van der Werf, S and van Dijk, G and Rijpkema, M and Fernandez, G},
doi = {10.1089/neu.2010.1298},
issn = {0897-7151},
year = {2010},
date = {2010-01-01},
journal = {Journal of Neurotrauma},
volume = {27},
pages = {1585--1595},
abstract = {Memory deficits are among the most frequently reported sequelae of mild traumatic brain injury (MTBI), especially early after injury. To date, these cognitive deficits remain poorly understood, as in most patients the brain is macroscopically intact. To identify the mechanism by which MTBI causes declarative memory impairments, we probed the functionality of the medial temporal lobe (MTL) and the prefrontal cortex (PFC), within 6 weeks after injury in 43 patients from a consecutive cohort, and matched healthy controls. In addition to neuropsychological measures of declarative memory and other cognitive domains, all subjects underwent functional magnetic resonance imaging (fMRI). Behavioral results showed poorer declarative memory performance in patients than controls, and decreasing performance with increasing duration of post-traumatic amnesia (a measure of injury severity). Task performance in the scanner was, as intended by the task and design, similar in patients and controls, and did not relate to injury severity. The task used reliably activated the MTL and PFC. Although we did not find significant differences in brain activity when comparing patients and controls, we revealed, in agreement with our neuropsychological findings, an inverse correlation between MTL activity and injury severity. In contrast, no difference in prefrontal activation was found between patients and controls, nor was there a relation with injury severity. On a behavioral level, injury severity was inversely related to declarative memory performance. In all, these findings suggest that reduced medial temporal functionality may contribute to poorer declarative memory performance in the post-acute stage of MTBI, especially in patients with longer post-traumatic amnesia.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Govind, Varan; Gold, Stuart; Kaliannan, Krithica; Saigal, Gaurav; Falcone, Steven; Arheart, Kristopher L; Harris, Leo; Jagid, Jonathan; Maudsley, Andrew A
Whole-brain proton MR spectroscopic imaging of mild-to-moderate traumatic brain injury and correlation with neuropsychological deficits Journal Article
In: Journal of Neurotrauma, vol. 27, pp. 483–496, 2010.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Govind2010,
title = {Whole-brain proton MR spectroscopic imaging of mild-to-moderate traumatic brain injury and correlation with neuropsychological deficits},
author = {Govind, Varan and Gold, Stuart and Kaliannan, Krithica and Saigal, Gaurav and Falcone, Steven and Arheart, Kristopher L and Harris, Leo and Jagid, Jonathan and Maudsley, Andrew A},
year = {2010},
date = {2010-01-01},
journal = {Journal of Neurotrauma},
volume = {27},
pages = {483--496},
address = {Department of Radiology, University of Miami School of Medicine, Miami, Florida 33136, USA. VGovind@med.miami.edu},
abstract = {Changes in the distribution of the magnetic resonance (MR)-observable brain metabolites N-acetyl aspartate (NAA), total choline (Cho), and total creatine (Cre), following mild-to-moderate closed-head traumatic brain injury (mTBI) were evaluated using volumetric proton MR spectroscopic imaging (MRSI). Studies were carried out during the subacute time period following injury, and associations of metabolite indices with neuropsychological test (NPT) results were evaluated. Twenty-nine subjects with mTBI and Glasgow Coma Scale (GCS) scores of 10-15 were included. Differences in individual metabolite and metabolite ratio distributions relative to those of age-matched control subjects were evaluated, as well as analyses by hemispheric lobes and tissue types. Primary findings included a widespread decrease of NAA and NAA/Cre, and increases of Cho and Cho/NAA, within all lobes of the TBI subject group, and with the largest differences seen in white matter. Examination of the association between all of the metabolite measures and the NPT scores found the strongest negative correlations to occur in the frontal lobe and for Cho/NAA. No significant correlations were found between any of the MRSI or NPT measures and the GCS. These results demonstrate that significant and widespread alterations of brain metabolites occur as a result of mild-to-moderate TBI, and that these measures correlate with measures of cognitive performance.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Gasparovic, Charles; Yeo, Ronald; Mannell, Maggie; Ling, Josef; Elgie, Robert; Phillips, John; Doezema, David; Mayer, Andrew R
Neurometabolite concentrations in gray and white matter in mild traumatic brain injury: an 1H-magnetic resonance spectroscopy study Journal Article
In: Journal of Neurotrauma, vol. 26, pp. 1635–1643, 2009.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Gasparovic2009,
title = {Neurometabolite concentrations in gray and white matter in mild traumatic brain injury: an 1H-magnetic resonance spectroscopy study},
author = {Gasparovic, Charles and Yeo, Ronald and Mannell, Maggie and Ling, Josef and Elgie, Robert and Phillips, John and Doezema, David and Mayer, Andrew R},
year = {2009},
date = {2009-01-01},
journal = {Journal of Neurotrauma},
volume = {26},
pages = {1635--1643},
address = {The Mind Research Network, Albuquerque, New Mexico 7131, USA. chuck@unm.edu},
abstract = {Single-voxel proton magnetic resonance imaging ((1)H-MRS) and proton MR spectroscopic imaging ((1)H-MRSI) were used to compare brain metabolite levels in semi-acute mild traumatic brain injury (mTBI) patients (n = 10) and matched healthy controls (n = 9). The (1)H-MRS voxel was positioned in the splenium, a region known to be susceptible to axonal injury in TBI, and a single (1)H-MRSI slice was positioned above the lateral ventricles. To increase sensitivity to the glutamate (Glu) and the combined glutamate-glutamine (Glx) signal, an inter-pulse echo time shown to emphasize the major Glu signals was used along with an analysis method that reduces partial volume errors by using water as a concentration standard. Our preliminary findings indicate significantly lower levels of gray matter Glx and higher levels of white matter creatine-phosphocreatine (Cr) in mTBI subjects relative to healthy controls. Furthermore, Cr levels were predictive of executive function and emotional distress in the combined groups. These results suggest that perturbations in Cr, a critical component of the brain's energy metabolism, and Glu, the brain's major neurotransmitter, may occur following mTBI. Moreover, the different pattern of results for gray and white matter suggests tissue-specific metabolic responses to mTBI.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Ruan, Shuolun; Noyes, Katia; Bazarian, Jeffrey J
The economic impact of S-100B as a pre-head CT screening test on emergency department management of adult patients with mild traumatic brain injury Journal Article
In: Journal of Neurotrauma, vol. 26, pp. 1655–1664, 2009.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Ruan2009,
title = {The economic impact of S-100B as a pre-head CT screening test on emergency department management of adult patients with mild traumatic brain injury},
author = {Ruan, Shuolun and Noyes, Katia and Bazarian, Jeffrey J},
year = {2009},
date = {2009-01-01},
journal = {Journal of Neurotrauma},
volume = {26},
pages = {1655--1664},
address = {Department of Community and Preventive Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA. shuolun.ruan@aya.yale.edu},
abstract = {Recent research suggests that serum S-100B may serve as a good pre-head computed tomography (CT) screening test because of its high sensitivity for abnormal head CT scans. The potential economic impact of using S-100B in the emergency department setting for management of adult patients with isolated mild traumatic brain injury (mTBI) has not been evaluated despite its clinical implementation in Europe. Using evidence from the literature, we constructed a decision tree to compare the average cost per patient of using S-100B as a pre-head CT screening test to the current practice of ordering CT scans based on patients' presenting symptoms without the aid of S-100B. When compared to scanning 45-77% of isolated mTBI patients based upon their presenting symptoms, using S-100B as a pre-head CT screen does not lower hospital costs ($281 versus $160), primarily due to its low specificity for abnormal head CT scans. Sensitivity analyses showed, however, that S-100B becomes cost-lowering when the proportion of mTBI patients being scanned exceeds 78%, or when final CT scan results require 96 min or more than the wait for blood test results. Generally speaking, if blood test results require less time than imaging, and if head CT scan rates for patients with isolated mTBI are relatively high, using S-100B will lower costs. Recommendations for using S-100B as a screening tool should account for setting-specific characteristics and their consequent economic impacts. Despite its high sensitivity and excellent negative predictive value, serum S-100B has low specificity and low positive predictive value, limiting its ability to reduce numbers of CT scans and hospital costs.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Chen, Jen Kai; Johnston, Karen M; Petrides, Michael; Ptito, Alain
Recovery from mild head injury in sports: evidence from serial functional magnetic resonance imaging studies in male athletes Journal Article
In: Clinical Journal of Sport Medicine, vol. 18, pp. 241–247, 2008.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Chen2008a,
title = {Recovery from mild head injury in sports: evidence from serial functional magnetic resonance imaging studies in male athletes},
author = {Chen, Jen Kai and Johnston, Karen M and Petrides, Michael and Ptito, Alain},
year = {2008},
date = {2008-01-01},
journal = {Clinical Journal of Sport Medicine},
volume = {18},
pages = {241--247},
address = {Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.},
abstract = {OBJECTIVE: To examine functional brain activation patterns before and after postconcussive symptoms (PCS) resolution. DESIGN: Prospective serial study with male athletes using functional magnetic resonance imaging (fMRI). SETTING: Hospital laboratory and imaging facility. PARTICIPANTS: 9 symptomatic concussed athletes who experienced persisting PCS at least 1 month postinjury and 6 healthy athletes. INTERVENTIONS: All athletes filled out a PCS checklist and underwent an fMRI session during which they performed a working-memory task. MAIN OUTCOME MEASUREMENTS: Behavioral outcomes were response speed and accuracy on the working memory tasks performed during the fMRI session. Functional imaging outcomes were blood oxygen level-dependent fMRI activation patterns associated with a working memory task. RESULTS:: There was no difference in behavioral performance between the groups. Despite normal structural MRI findings, all symptomatic concussed athletes initially showed atypical brain activation patterns in the dorsolateral prefrontal cortex (DLPC). Compared to the initial postinjury evaluation, those athletes at follow-up with PCS resolved showed significant increases in activation in the left DLPC. Concussed athletes whose PCS status remained unchanged at follow-up continued to show atypical activation in DLPC. Healthy athletes showed remarkably clear and consistent brain activations in DLPC initially as well as in follow-up, highlighting the test-retest reliability of fMRI. CONCLUSIONS: The results demonstrate the feasibility of using fMRI to detect an underlying pathology in symptomatic concussed athletes with normal structural imaging results and its potential to document recovery. Such information may be of considerable value for clinical judgment and patient management.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Ptito, Alain; Chen, Jen-Kai; Johnston, Karen M
Contributions of functional magnetic resonance imaging (fMRI) to sport concussion evaluation Journal Article
In: NeuroRehabilitation, vol. 22, pp. 217–227, 2007.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Ptito2007,
title = {Contributions of functional magnetic resonance imaging (fMRI) to sport concussion evaluation},
author = {Ptito, Alain and Chen, Jen-Kai and Johnston, Karen M},
year = {2007},
date = {2007-01-01},
journal = {NeuroRehabilitation},
volume = {22},
pages = {217--227},
address = {Montreal Neurological Institute McGill University, Montreal, Quebec, Canada. alain.ptito@mcgill.ca},
abstract = {Mild traumatic brain injury (mTBI) in contact sport is a problem of such magnitude that improved approaches to diagnosis, investigation and management are urgent. Concussion has traditionally been described as a transient, fully reversible, cerebral dysfunction. However, this seemingly 'mild' injury sometimes results in long-lasting and disabling post-concussion symptoms (PCS) and abnormal neuropsychological profiles characteristic of frontal and/or temporal lobe dysfunction. At present, the pathological changes following concussion remain unclear, but it is now widely accepted that concussion results mainly in functional disturbance rather than structural damage. Therefore, functional imaging techniques can help in demonstrating brain abnormalities undetectable by structural imaging methods. This paper will review the use of functional magnetic resonance imaging (fMRI) in studies of concussion. Our existing and ongoing fMRI studies will be described as examples to highlight the potential and contribution of this non-invasive functional neuroimaging technique in the assessment of sports-related concussion and its management. [References: 54]},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Kirov, Ivan; Fleysher, Lazar; Babb, James S; Silver, Jonathan M; Grossman, Robert I; Gonen, Oded
Characterizing 'mild' in traumatic brain injury with proton MR spectroscopy in the thalamus: Initial findings Journal Article
In: Brain Injury, vol. 21, pp. 1147–1154, 2007.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Kirov2007,
title = {Characterizing 'mild' in traumatic brain injury with proton MR spectroscopy in the thalamus: Initial findings},
author = {Kirov, Ivan and Fleysher, Lazar and Babb, James S and Silver, Jonathan M and Grossman, Robert I and Gonen, Oded},
year = {2007},
date = {2007-01-01},
journal = {Brain Injury},
volume = {21},
pages = {1147--1154},
address = {Department of Radiology, New York, USA.},
abstract = {OBJECTIVE: Although most mild traumatic brain injury (mTBI) patients suffer any of several post-concussion symptoms suggestive of thalamic involvement, they rarely present with any MRI-visible pathology. The aim here, therefore, is to characterize their thalamic metabolite levels with proton MR spectroscopy (1H-MRS) compared with healthy controls. METHODS: T1-weighted MRI and multi-voxel 1H-MRS were acquired at 3 Tesla from 20 mTBI (Glasgow Coma Scale score of 15-13) patients, 19-59 years old, 0-7 years post-injury; and from 17 age and gender matched healthy controls. Mixed model regression was used to compare patients and controls with respect to the mean absolute N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) levels within each thalamus. RESULTS: The mTBI-induced thalamic metabolite concentration changes were under +/- 13.0% for NAA, +/- 13.5% for Cr and +/- 18.8% for Cho relative to their corresponding concentrations in the controls: NAA: 10.08 +/- 0.30 (mean +/- standard error), Cr: 5.62 +/- 0.18 and Cho: 2.08 +/- 0.09 mM. These limits represent the minimal detectable differences between the two cohorts. CONCLUSION: The change in metabolic levels in the thalamus of patients who sustained clinically defined mTBI could be an instrumental characteristic of 'mildness'. 1H-MRS could, therefore, serve as an objective laboratory indicator for differentiating 'mild' from more severe categories of head-trauma, regardless of the presence or lack of current clinical symptoms.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Kraus, Marilyn F; Susmaras, Teresa; Caughlin, Benjamin P; Walker, Corey J; Sweeney, John A; Little, Deborah M
White matter integrity and cognition in chronic traumatic brain injury: a diffusion tensor imaging study Journal Article
In: Brain, vol. 130, pp. 2508–2519, 2007.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Kraus2007,
title = {White matter integrity and cognition in chronic traumatic brain injury: a diffusion tensor imaging study},
author = {Kraus, Marilyn F and Susmaras, Teresa and Caughlin, Benjamin P and Walker, Corey J and Sweeney, John A and Little, Deborah M},
year = {2007},
date = {2007-01-01},
journal = {Brain},
volume = {130},
pages = {2508--2519},
address = {Department of Psychiatry, University of Illinois at Chicago Medical Center, Chicago, IL, USA. mkraus@psych.uic.edu},
abstract = {Traumatic brain injury (TBI) is a serious public health problem. Even injuries classified as mild, the most common, can result in persistent neurobehavioural impairment. Diffuse axonal injury is a common finding after TBI, and is presumed to contribute to outcomes, but may not always be apparent using standard neuroimaging. Diffusion tensor imaging (DTI) is a more recent method of assessing axonal integrity in vivo. The primary objective of the current investigation was to characterize white matter integrity utilizing DTI across the spectrum of chronic TBI of all severities. A secondary objective was to examine the relationship between white matter integrity and cognition. Twenty mild, 17 moderate to severe TBI and 18 controls underwent DTI and neuropsychological testing. Fractional anisotropy, axial diffusivity and radial diffusivity were calculated from the DTI data. Fractional anisotropy was the primary measure of white matter integrity. Region of interest analysis included anterior and posterior corona radiata, cortico-spinal tracts, cingulum fibre bundles, external capsule, forceps minor and major, genu, body and splenium of the corpus callosum, inferior fronto-occipital fasciculus, superior longitudinal fasciculus and sagittal stratum. Cognitive domain scores were calculated from executive, attention and memory testing. Decreased fractional anisotropy was found in all 13 regions of interest for the moderate to severe TBI group, but only in the cortico-spinal tract, sagittal stratum and superior longitudinal fasciculus for the mild TBI group. White Matter Load (a measure of the total number of regions with reduced FA) was negatively correlated with all cognitive domains. Analysis of radial and axial diffusivity values suggested that all severities of TBI can result in a degree of axonal damage, while irreversible myelin damage was only apparent for moderate to severe TBI. The present data emphasize that white matter changes exist on a spectrum, including mild TBI. An index of global white matter neuropathology (White Matter Load) was related to cognitive function, such that greater white matter pathology predicted greater cognitive deficits. Mechanistically, mild TBI white matter changes may be primarily due to axonal damage as opposed to myelin damage. The more severe injuries impact both. DTI provides an objective means for determining the relationship of cognitive deficits to TBI, even in cases where the injury was sustained years prior to the evaluation.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Bazarian, Jeffrey J; Blyth, Brian; Cimpello, Lynn
Bench to bedside: evidence for brain injury after concussion--looking beyond the computed tomography scan Journal Article
In: Academic Emergency Medicine, vol. 13, pp. 199–214, 2006.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Bazarian2006a,
title = {Bench to bedside: evidence for brain injury after concussion--looking beyond the computed tomography scan},
author = {Bazarian, Jeffrey J and Blyth, Brian and Cimpello, Lynn},
year = {2006},
date = {2006-01-01},
journal = {Academic Emergency Medicine},
volume = {13},
pages = {199--214},
address = {Department of Emergency Medicine, Strong Memorial Hospital, University of Rochester, Rochester, NY 14642, USA. jeff_bazarian@urmc.rochester.edu},
abstract = {The emergency management of cerebral concussion typically centers on the decision to perform a head computed tomography (CT) scan, which only rarely detects hemorrhagic lesions requiring neurosurgery. The absence of hemorrhage on CT scan often is equated with a lack of brain injury. However, observational studies revealing poor long-term cognitive outcome after concussion suggest that brain injury may be present despite a normal CT scan. To explore this idea further, the authors reviewed the evidence for objective neurologic injury in humans after concussion, with particular emphasis on those with a normal brain CT. This evidence comes from studies involving brain tissue pathology, CT scanning, magnetic resonance image (MRI) scanning, serum biomarkers, formal cognitive and balance tests, functional MRI, positron emission tomography, and single-photon emission computed tomography scanning. Each section is accompanied by technical information to help the reader understand what these tests are, not to endorse their use clinically. The authors discuss the strengths and weaknesses of the evidence in each case. These reports make a compelling case for the existence of concussion as a clinically relevant disease with demonstrable neurologic pathology. Areas for future emergency medicine research are suggested. [References: 169]},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Chappell, M H; Ulug, A M; Zhang, L; Heitger, M H; Jordan, B D; Zimmerman, R D; Watts, R
Distribution of microstructural damage in the brains of professional boxers: A diffusion MRI study Journal Article
In: Journal of Magnetic Resonance Imaging, vol. 24, pp. 537–542, 2006, ISSN: 1053-1807.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Chappell2006,
title = {Distribution of microstructural damage in the brains of professional boxers: A diffusion MRI study},
author = {Chappell, M H and Ulug, A M and Zhang, L and Heitger, M H and Jordan, B D and Zimmerman, R D and Watts, R},
doi = {10.1002/jmri.20656},
issn = {1053-1807},
year = {2006},
date = {2006-01-01},
journal = {Journal of Magnetic Resonance Imaging},
volume = {24},
pages = {537--542},
abstract = {Purpose: To investigate and localize cerebral abnormalities in professional boxers with no history of moderate or severe head trauma. Materials and Methods: Diffusion tensor imaging (DTI) was used to determine the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in the brains of 81 professional male boxers and 12 male control subjects. Voxel-based analysis (VBA) of both the diffusion and anisotropy values was performed using statistical parametric mapping (SPM). From this objective analysis, regions of microstructural abnormalities in the brains of the boxers were located. Results: Increases in the ADC, and decreases in FA were identified in deep white matter (WM), while decreases in ADC were identified in cortical gray matter (GM). Regions of positive correlation between ADC and age were also found in both the boxer and control groups, although the regions and strength of the correlation were not the same in each group. Conclusion: Using VBA, we localized previously unreported abnormalities in the brains of professional boxers. These abnormalities are assumed to reflect cumulative (chronic) brain injury resulting from nonsevere head trauma.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Cimatti, M
Assessment of metabolic cerebral damage using proton magnetic resonance spectroscopy in mild traumatic brain injury Journal Article
In: Journal of Neurosurgical Sciences, vol. 50, pp. 83–88, 2006.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Cimatti2006,
title = {Assessment of metabolic cerebral damage using proton magnetic resonance spectroscopy in mild traumatic brain injury},
author = {Cimatti, M},
year = {2006},
date = {2006-01-01},
journal = {Journal of Neurosurgical Sciences},
volume = {50},
pages = {83--88},
address = {Department of Neurological Sciences and Neurosurgery, University La Sapienza, Rome, Italy.},
abstract = {AIM: We want to appraise, through proton magnetic resonance spectroscopy (H1-MRI), the NAA's values and it's changing in cerebral tissue in consequence of cranial trauma. METHODS: Six patients with TBI undergo to H1-MRI to asses the changes occurring briefly after trauma in the spectrum's composition. RESULTS: As far as the first two cases we founded a lowering of the NAA's values. In the other four cases the NAA values were normal in all but one, which slightly brought the values of the NAA/Cr and NAA/Cho lower in comparison to the standard values. CONCLUSIONS: Existing a correlation between NAA and ATP it can be drawn that the reduction of NAA is correlated to energetic type damage. Despite the smallness of data, it remains really important that we should have a tool to monitor the cerebral metabolic picture after a mild trauma.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Chen, J K; Johnston, K M; Frey, S; Petrides, M; Worsley, K; Ptito, A
Functional abnormalities in symptomatic concussed athletes: an fMRI study Journal Article
In: Neuroimage, vol. 22, pp. 68–82, 2004.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Chen2004,
title = {Functional abnormalities in symptomatic concussed athletes: an fMRI study},
author = {Chen, J K and Johnston, K M and Frey, S and Petrides, M and Worsley, K and Ptito, A},
year = {2004},
date = {2004-01-01},
journal = {Neuroimage},
volume = {22},
pages = {68--82},
address = {Neuropsychology Department/Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.},
abstract = {Our aim was to quantify with functional magnetic resonance imaging (fMRI) changes in brain activity in concussed athletes and compare the results with those of normal control subjects. Regional brain activations associated with a working memory task were obtained from a group of concussed athletes (15 symptomatic, 1 asymptomatic) and eight matched control subjects, using blood oxygen level dependent (BOLD) fMRI. The average percent signal change from baseline to working memory condition in each region of interest was computed. Symptomatic concussed athletes demonstrated task-related activations in some but not all the regions of interest, even when they performed as well as the control subjects. Furthermore, several concussed athletes had additional increases in activity outside the regions of interest, not seen in the control group. Quantitative analysis of BOLD signals within regions of interest revealed that, in general, concussed athletes had different BOLD responses compared to the control subjects. The task-related activation pattern of the one symptom-free athlete was comparable to that of the control group. We also repeated the study in one athlete whose symptoms had resolved. On the first study, when he was still symptomatic, less task-related activations were observed. On follow-up, once his symptoms had disappeared, the task-related activations became comparable to those of the control group. These results demonstrate the potential of fMRI, in conjunction with the working memory task, to identify an underlying pathology in symptomatic concussed individuals with normal structural imaging results.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Xiao, Xing-Yi; Xue, Guan-Sheng; Xu, Guo-Zhen; Yin, Xiao-Mei
Change and clinical significance of cerebral blood flow after concussion of brain detected with three-dimensional transcranial Doppler Journal Article
In: Chinese Journal of Traumatology, vol. 6, pp. 124–126, 2003.
BibTeX | Tags: Imaging & EEG Physiopathology
@article{Xiao2003,
title = {Change and clinical significance of cerebral blood flow after concussion of brain detected with three-dimensional transcranial Doppler},
author = {Xiao, Xing-Yi and Xue, Guan-Sheng and Xu, Guo-Zhen and Yin, Xiao-Mei},
year = {2003},
date = {2003-01-01},
journal = {Chinese Journal of Traumatology},
volume = {6},
pages = {124--126},
address = {Department of Emergency, 205th Hospital of PLA, Jinzhou 121001, China. 225205225205@sina.com},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Shaw, Nigel A
The neurophysiology of concussion Journal Article
In: Progress in Neurobiology, vol. 67, pp. 281–344, 2002, ISSN: 0301-0082.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Shaw2002,
title = {The neurophysiology of concussion},
author = {Shaw, Nigel A},
doi = {10.1016/s0301-0082(02)00018-7},
issn = {0301-0082},
year = {2002},
date = {2002-01-01},
journal = {Progress in Neurobiology},
volume = {67},
pages = {281--344},
abstract = {Cerebral concussion is both the most common and most puzzling type of traumatic brain injury (TBI). It is normally produced by acceleration (or deceleration) of the head and is characterized by a sudden brief impairment of consciousness, paralysis of reflex activity and loss of memory. It has long been acknowledged that one of the most worthwhile techniques for studying the acute pathophysiology of concussion is by the recording of neurophysiological activity such as the electroencephalogram (EEG) and sensory evoked potentials (EPs) from experimental animals. In the first parts of this review, the majority of such studies conducted during the past half century are critically reviewed. When potential methodological flaws and limitations such as anesthetic protocols, infliction of multiple blows and delay in onset of recordings were taken into account, two general principles could be adduced. First, the immediate post-concussive EEG was excitatory or epileptiform in nature. Second, the cortical EP waveform was totally lost during this period. In the second parts of this review, five theories of concussion which have been prominent during the past century are summarized and supportive evidence assessed. These are the vascular, reticular, centripetal, pontine cholinergic and convulsive hypotheses. It is concluded that only the convulsive theory is readily compatible with the neurophysiological data and can provide a totally viable explanation for concussion. The chief tenet of the convulsive theory is that since the symptoms of concussion bear a strong resemblance to those of a generalized epileptic seizure, then it is a reasonable assumption that similar pathobiological processes underlie them both. Further, it is demonstrated that EPs and EEGs recorded acutely following concussive trauma are indeed the same or similar to those obtained following the induction of a state of generalized seizure activity (GSA). According to the present incarnation of the convulsive theory, the energy imparted to the brain by the sudden mechanical loading of the head may generate turbulent rotatory and other movements of the cerebral hemispheres and so increase the chances of a tissue-deforming collision or impact between the cortex and the boney walls of the skull. In this conception, loss of consciousness is not orchestrated by disruption or interference with the function of the brainstem reticular activating system. Rather, it is due to functional deafferentation of the cortex as a consequence of diffuse mechanically-induced depolarization and synchronized discharge of cortical neurons. A convulsive theory can also explain traumatic amnesia, autonomic disturbances and the miscellaneous collection of symptoms of the post-concussion syndrome more adequately than any of its rivals. In addition, the symptoms of minor concussion (a.k.a. being stunned, dinged, or dazed) are often strikingly similar to minor epilepsy such as petit mal. The relevance of the convulsive theory to a number of associated problems is also discussed. These include the relationship between concussion and more serious types of closed head injury, the utility of animal models of severe brain trauma, the etiology of the cognitive deficits which may linger long after a concussive injury, the use of concussive (captive bolt) techniques to stun farm animals prior to slaughter and the question of why some animals (such as the woodpecker) can tolerate massive accelerative forces without being knocked out.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Hofman, P A; Stapert, S Z; van Kroonenburgh, M J; Jolles, J; de Kruijk, J; Wilmink, J T
MR imaging, single-photon emission CT, and neurocognitive performance after mild traumatic brain injury Journal Article
In: AJNR: American Journal of Neuroradiology, vol. 22, pp. 441–449, 2001.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Hofman2001,
title = {MR imaging, single-photon emission CT, and neurocognitive performance after mild traumatic brain injury},
author = {Hofman, P A and Stapert, S Z and van Kroonenburgh, M J and Jolles, J and de Kruijk, J and Wilmink, J T},
year = {2001},
date = {2001-01-01},
journal = {AJNR: American Journal of Neuroradiology},
volume = {22},
pages = {441--449},
address = {Department of Radiology, University Hospital Maastricht, The Netherlands.},
abstract = {BACKGROUND AND PURPOSE: Mild traumatic brain injury (mTBI) (Glasgow Coma Scale = 14-15) is a common neurologic disorder and a common cause of neurocognitive deficits in the young population. Most patients recover fully from mTBI, but 15% to 29% of patients have persistent neurocognitive problems. Although a partially organic origin is considered likely, little brain imaging evidence exists for this assumption. The aims of the present study were to establish the prevalence of posttraumatic lesions in mTBI patients on MR images and to assess the relation between these imaging findings and posttraumatic symptoms. Secondly, we explored the value of early posttraumatic single-photon emission CT (SPECT) for the evaluation of mTBI. METHODS: Twenty-one consecutive patients were included in the study. Patients underwent MR examination, technetium-99m hexamethylpropylene amine oxime SPECT, and neurocognitive assessment within 5 days after injury. Neurocognitive follow-up was conducted 2 and 6 months after injury, and MR imaging was repeated after 6 months. Lesion size and brain atrophy were measured on the MR studies. RESULTS: Twelve (57%) of 21 patients had abnormal MR findings, and 11 (61%) of 18 had abnormal SPECT findings. Patients with abnormal MR or SPECT findings had brain atrophy at follow-up. The mean neurocognitive performance of all subjects was within normal range. There was no difference in neurocognitive performance between patients with normal and abnormal MR findings. Patients with abnormal MR findings only showed significantly slower reaction times during a reaction-time task. Seven patients had persistent neurocognitive complaints and one patient met the criteria for a postconcussional syndrome. CONCLUSION: Brain lesions are common after mTBI; up to 77% of patients may have abnormal findings either on MR images or SPECT scans, and these lesions may lead to brain atrophy. The association between hypoperfusion seen on acute SPECT and brain atrophy after 6 months suggests the possibility of (secondary) ischemic brain damage. There is only a weak correlation between neuroimaging findings and neurocognitive outcome.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Nariai, T; Suzuki, R; Ohta, Y; Ohno, K; Hirakawa, K
Focal cerebral hyperemia in postconcussive amnesia Journal Article
In: Journal of Neurotrauma, vol. 18, pp. 1323–1332, 2001.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Nariai2001,
title = {Focal cerebral hyperemia in postconcussive amnesia},
author = {Nariai, T and Suzuki, R and Ohta, Y and Ohno, K and Hirakawa, K},
year = {2001},
date = {2001-01-01},
journal = {Journal of Neurotrauma},
volume = {18},
pages = {1323--1332},
address = {Department of Neurosurgery, Tokyo Medical and Dental University, Japan. nariai.nsrg@tmd.ac.jp},
abstract = {Transient amnesia caused by minor head injury is commonly encountered in daily neurosurgical practice, but the mechanism of such amnesia has not been extensively studied. We measured the regional cerebral blood flow (rCBF) of patients with postconcussive amnesia with Xe/CT CBF to examine whether a focal disturbance of CBF exists. The Xe/CT CBF study was performed in eight patients with closed head injury without organic cerebral lesion while they were suffering from posttraumatic amnesia (concussion group). The time interval between accident and CBF measurement was less than 2 h in three patients, 5-6 h in two, 8-9 h in two, and 18 in one. The results were compared with those of nine normal volunteers and eight other age-matched patients who recovered without any neurological deficit despite the presence of hemorrhagic regions (mild hemorrhage group). The rCBF of the concussion group was significantly elevated in the bilateral mesial temporal cortex in comparison to the normal group. The rCBF in the mild hemorrhage group was lower than that of normal controls in all regions. The analysis of right-left difference in CBF indicated that there was significant asymmetry (right \> left) in the frontal and temporal cortex in the concussion group, but not in the normal and mild hemorrhage group. This Xe/CT CBF study in acute stages of cerebral concussion, in which patients were amnestic, detected focal cerebral hyperemia. Such hyperemia in regions closely related to human memory function may be the result of vasoparalysis or the compensatory activation of memory circuits after denervation injury.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Bergsneider, M; Hovda, D A; McArthur, D L; Etchepare, M; Huang, S C; Sehati, N; Satz, P; Phelps, M E; Becker, D P
Metabolic recovery following human traumatic brain injury based on FDG-PET: time course and relationship to neurological disability Journal Article
In: Journal of Head Trauma Rehabilitation, vol. 16, pp. 135–148, 2001.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Bergsneider2001,
title = {Metabolic recovery following human traumatic brain injury based on FDG-PET: time course and relationship to neurological disability},
author = {Bergsneider, M and Hovda, D A and McArthur, D L and Etchepare, M and Huang, S C and Sehati, N and Satz, P and Phelps, M E and Becker, D P},
year = {2001},
date = {2001-01-01},
journal = {Journal of Head Trauma Rehabilitation},
volume = {16},
pages = {135--148},
address = {Department of Surgery, Division of Neurosurgery, UCLA Brain Research Institute, Harbor-University of California at Los Angeles Medical Center, USA.},
abstract = {OBJECTIVE: Utilizing [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET), we assessed the temporal pattern and the correlation of functional and metabolic recovery following human traumatic brain injury. DESIGN AND SUBJECTS: Fifty-four patients with injury severity ranging from mild to severe were studied. Thirteen of these patients underwent both an acute and delayed FDG-PET study. RESULTS: Analysis of the pooled global cerebral metabolic rate of glucose (CMRglc) values revealed that the intermediate metabolic reduction phase begins to resolve approximately one month following injury, regardless of injury severity. The correlation, in the 13 patients studied twice, between the extent of change in neurologic disability, assessed by the Disability Rating Scale (DRS), and the change in CMRglc from the early to late period was modest (r = -0.42). Potential explanations for this rather poor correlation are discussed. A review of the pertinent literature regarding the use of PET and related imaging modalities, including single photon emission tomography (SPECT) for the assessment of patients following traumatic brain injury is given. CONCLUSION: The dynamic profile of CMRglc that changes following traumatic brain injury is seemingly stereotypic across a broad range and severity of injury types. Quantitative FDG-PET cannot be used as a surrogate technique for estimating degree of global functional recovery following traumatic brain injury.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
McAllister, T W; Sparling, M B; Flashman, L A; Guerin, S J; Mamourian, A C; Saykin, A J
Differential working memory load effects after mild traumatic brain injury Journal Article
In: Neuroimage, vol. 14, pp. 1004–1012, 2001.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{McAllister2001,
title = {Differential working memory load effects after mild traumatic brain injury},
author = {McAllister, T W and Sparling, M B and Flashman, L A and Guerin, S J and Mamourian, A C and Saykin, A J},
year = {2001},
date = {2001-01-01},
journal = {Neuroimage},
volume = {14},
pages = {1004--1012},
address = {Section of Neuropsychiatry and Brain Imaging Laboratory, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA.},
abstract = {The objective of this study was to explore the effects of increasing working memory (WM) processing load on previously observed abnormalities in activation of WM circuitry shortly after mild traumatic brain injury (MTBI). Brain activation patterns in response to increasing WM processing load (auditory n-back: 0-, 1-, 2-, and 3-back conditions) were assessed with fMRI in 18 MTBI patients within 1 month of their injury and in 12 healthy controls. Performance accuracy on these tasks was also measured. Brain activation patterns differed between MTBI patients and controls in response to increasing WM processing loads. Controls maintained their ability to increase activation in regions of WM circuitry with each increase in WM processing load. MTBI patients showed disproportionately increased activation during the moderate processing load condition, but very little increase in activation associated with the highest processing load condition. Task performance did not differ significantly between groups on any task condition. MTBI patients showed a different pattern of allocation of processing resources associated with a high processing load condition compared to healthy controls, despite similar task performance. This suggests that injury-related changes in ability to activate or modulate WM processing resources might underlie some of the memory complaints after MTBI.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Mussack, T; Biberthaler, P; Wiedemann, E; Kanz, K G; Englert, A; Gippner-Steppert, C; Jochum, M
S-100b as a screening marker of the severity of minor head trauma (MHT)--a pilot study Journal Article
In: Acta Neurochirurgica - Supplement, vol. 76, pp. 393–396, 2000.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Mussack2000,
title = {S-100b as a screening marker of the severity of minor head trauma (MHT)--a pilot study},
author = {Mussack, T and Biberthaler, P and Wiedemann, E and Kanz, K G and Englert, A and Gippner-Steppert, C and Jochum, M},
year = {2000},
date = {2000-01-01},
journal = {Acta Neurochirurgica - Supplement},
volume = {76},
pages = {393--396},
address = {Chirurgische Klinik, Kliniken Innenstadt, Ludwig-Maximilians-Universitat, Munchen, Germany.},
abstract = {Due to its neural tissue specificity S-100b is considered as a screening marker of cerebral injury in head trauma patients. However, the occurrence and relevance of an increased S-100b serum level in minor head trauma (MHT) is still debated. Therefore, the purpose of our study was to evaluate the diagnostic utility of S-100b measurements in a level I trauma center emergency room (ER). Eighty patients presenting with clinical symptoms of MHT (GCS score of 13-15, transitory loss of consciousness, amnesia, nausea) were prospectively recruited. Blood samples were drawn at 0 h, 6 h and 24 h after admission, and a cerebral computed tomography (CT) was performed. The reference group consisted of 10 patients with severe head injury (GCS score \< 8), the control group of 20 healthy volunteers. Concentrations of S-100b in serum were determined by an immunoluminometric assay. The results were compared with the plasma levels of polymorphonuclear (PMN) elastase as an established general trauma marker. In the MHT group, the S-100b serum level revealed 1.26 +/- 0.57 ng/ml at study entry (73.46 +/- 47.53 min after trauma). In comparison, the S-100b concentration was significantly elevated in patients with severe head trauma (5.26 +/- 1.65 ng/ml},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Ingebrigtsen, T; Romner, B; Marup-Jensen, S; Dons, M; Lundqvist, C; Bellner, J; Alling, C; Borgesen, S E
The clinical value of serum S-100 protein measurements in minor head injury: a Scandinavian multicentre study Journal Article
In: Brain Injury, vol. 14, pp. 1047–1055, 2000.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Ingebrigtsen2000,
title = {The clinical value of serum S-100 protein measurements in minor head injury: a Scandinavian multicentre study},
author = {Ingebrigtsen, T and Romner, B and Marup-Jensen, S and Dons, M and Lundqvist, C and Bellner, J and Alling, C and Borgesen, S E},
year = {2000},
date = {2000-01-01},
journal = {Brain Injury},
volume = {14},
pages = {1047--1055},
address = {Department of Neurosurgery, University Hospital of Tromso, Norway. nevktoi@rito.no},
abstract = {PURPOSE: This study of patients with minor head injury was designed to investigate the relation of S-100 protein measurements to computed tomograpy (CT) findings and patients outcomes. Increased serum levels of this protein were hypothetized to predict intracranial pathology and increased frequency of post-concussion symptoms. METHODS: One hundred and eighty-two patients were studied with Glasgow Coma Scale scores of 13-15. The study recruited patients from three Scandinavian neurotrauma centres. Serum levels of S-100 protein were measured at admittance and CT scans of the brain were obtained within 24 hours postinjury in all patients. Outcome was evaluated with the Rivermead Postconcussion Symptoms Questionnaire (RPQ) 3 months after the injury. RESULTS: Increased serum level of S-100 protein was detected in 69 (38%) patients, and CT scan demonstrated intracranial pathology in 10 (5%) (brain contusion in seven, epidural haematoma in two, traumatic subarachnoid haemorrhage in one). The proportion of patients with detectable serum level was significantly (p \< 0.01) higher among those with intracranial pathology (90%) compared to those without (35%). The negative predictive value of an undetectable S-100 level was 0.99. Sixty-two per cent reported one or more post-concussion symptoms at follow-up. A trend was observed towards an increased frequency of post-concussion symptoms among patients with detectable serum levels. CONCLUSIONS: Undetectable serum level of S-100 protein predicts normal intracranial findings on CT scan. Determination of S-100 protein in serum may be used to select patients for CT scanning. Increased S-100 serum levels may be more related to post-concussion symptoms caused by mild traumatic brain injury than to symptoms of psychological origin.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Drake Jr., M E; Weate, S J; Newell, S A
Auditory evoked potentials in postconcussive syndrome Journal Article
In: Electromyography & Clinical Neurophysiology, vol. 36, pp. 457–462, 1996.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{DrakeJr.1996,
title = {Auditory evoked potentials in postconcussive syndrome},
author = {{Drake Jr.}, M E and Weate, S J and Newell, S A},
year = {1996},
date = {1996-01-01},
journal = {Electromyography \& Clinical Neurophysiology},
volume = {36},
pages = {457--462},
address = {Department of Neurology, Ohio State University College of Medicine, Columbus, USA.},
abstract = {The neuropsychiatric sequelae of minor head trauma have been the source of controversy. Most clinical and imaging studies have shown no alteration after concussion, but neuropsychological and neuropathological abnormalities have been reported. Some changes in neurophysiologic diagnostic tests have been described in postconcussive syndrome. We recorded middle latency auditory evoked potentials (MLR) and slow vertex responses (SVR) in 20 individuals with prolonged cognitive difficulties, behavior changes, dizziness, and headache after concussion. MLR is utilized alternating polarity clicks presented monaurally at 70 dB SL at 4 per second, with 40 dB contralateral masking. Five hundred responses were recorded and replicated from Cz-A1 and Cz-A2, with 50 ms. analysis time and 20-1000 Hz filter band pass. SVRs were recorded with the same montage, but used rarefaction clicks, 0.5 Hz stimulus rate, 500 ms. analysis time, and 1-50 Hz filter band pass. Na and Pa MLR components were reduced in amplitude in postconcussion patients. Pa latency was significantly longer in patients than in controls. SVR amplitudes were longer in concussed individuals, but differences in latency and amplitude were not significant. These changes may reflect posttraumatic disturbance in presumed subcortical MLR generators, or in frontal or temporal cortical structures that modulate them. Middle and long-latency auditory evoked potentials may be helpful in the evaluation of postconcussive neuropsychiatric symptoms.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Ford, M R; Khalil, M
Evoked potential findings in mild traumatic brain injury .1. Middle latency component augmentation and cognitive component attenuation Journal Article
In: Journal of Head Trauma Rehabilitation, vol. 11, pp. 1–15, 1996.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Ford1996,
title = {Evoked potential findings in mild traumatic brain injury .1. Middle latency component augmentation and cognitive component attenuation },
author = {Ford, M R and Khalil, M},
year = {1996},
date = {1996-01-01},
journal = {Journal of Head Trauma Rehabilitation},
volume = {11},
pages = {1--15},
abstract = {Abstract: Objective: To compare evoked potential (EP) and electroencephalogram (EEG) recordings from patients with suspected mild traumatic brain injury (TBI) versus normal controls using computerized EP and EEG analysis procedures. Design: Matched two-group comparison design, with a second matched replication group, and a second group of normals. Setting: Private, ambulatory, non-emergency facility specializing in assessment, pain management, and rehabilitation of spine and related injuries. Patients and Other Participants: Patients were 54 consecutive referrals for computerized EP/EEG evaluation with histories of primarily motor vehicle accidents and symptoms consistent with mild TBI. Normal controls were 27 screened volunteers. Patients were arbitrarily divided into two groups and matched to the controls on the basis of age and gender. Main Outcome Measures: Outcome measures not included in this phase of investigation. Auditory and visual EPs were obtained in resting and P300 task sessions (in which subjects counted the number of randomly occurring target stimuli). The paucity of existing Literature did not permit prediction of all critical EP or EEG variables. Results: Middle latency EP components tie, after brain stem responses yet before long latency, cognitive components) showed amplitude increases (auditory P1, P2, and N2, and visual P2, 50-220 milliseconds poststimulus). Long latency cognitive components (auditory and visual P300 and N3, 290-700 milliseconds) showed amplitude decreases. Similar findings were present in the replication group of patients and in comparison to a second group of normal controls. Conclusions: Significant and reliable EP differences were present in patients whose histories and symptoms were consistent with mild TBI.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Roberts, M A; Manshadi, F F; Bushnell, D L; Hines, M E
Neurobehavioural dysfunction following mild traumatic brain injury in childhood: a case report with positive findings on positron emission tomography (PET) Journal Article
In: Brain Injury, vol. 9, pp. 427–436, 1995.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Roberts1995,
title = {Neurobehavioural dysfunction following mild traumatic brain injury in childhood: a case report with positive findings on positron emission tomography (PET)},
author = {Roberts, M A and Manshadi, F F and Bushnell, D L and Hines, M E},
year = {1995},
date = {1995-01-01},
journal = {Brain Injury},
volume = {9},
pages = {427--436},
address = {Department of Pediatrics, University of Iowa College of Medicine, USA.},
abstract = {The present case study describes the neurobehavioural, neurodiagnostic, and positron emission tomography (PET) scan findings in a child who sustained a whiplash-type injury in a motor vehicle accident. Although neck and back pain were reported immediately, neurobehavioural symptoms, such as staring spells, gradually increased in frequency over a 2-year period following the accident. At 4 years after the accident the patient's symptoms persisted, as reported by teachers and parents, and more extensive diagnostic work-up was initiated. Standard EEG was normal while two ambulatory EEGs were abnormal and interpreted as epileptiform. A PET scan showed evidence of marked hypometabolism in both temporal lobes. Neuropsychological findings were consistent with PET findings and reflected verbal and visual memory deficits in the context of high average intelligence. Treatment with carbamazepine, verapamil, and fluoxetine greatly improved the patient's symptoms. The present case illustrates an example of a poor outcome in a paediatric case of mild traumatic brain injury, the importance of PET in demonstrating definitive evidence of brain dysfunction, and the child's positive response to anticonvulsant medication.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Eide, P K; Tysnes, O B
Early and late outcome in head injury patients with radiological evidence of brain damage Journal Article
In: Acta Neurologica Scandinavica, vol. 86, pp. 194–198, 1992.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Eide1992,
title = {Early and late outcome in head injury patients with radiological evidence of brain damage},
author = {Eide, P K and Tysnes, O B},
year = {1992},
date = {1992-01-01},
journal = {Acta Neurologica Scandinavica},
volume = {86},
pages = {194--198},
address = {Department of Neurosurgery, Haukeland Hospital, Bergen, Norway.},
abstract = {This study examined the early and late outcome in head injury patients with focal or multifocal (unilateral or bilateral) brain contusions revealed by computerized tomography (CT) scanning. The outcome was also evaluated in patients hospitalized due to brain concussion. Three months after the injury (the early outcome) 43% of the 86 cases with multifocal contusions on the CT scan were dead. As evaluated by the Glasgow Outcome Scale, all the 57 patients with a focal brain contusion, as well as the 117 cases with brain concussion, made a good recovery or were moderately disabled. The late outcome (1 to 5 years after injury) was evaluated in 78 cases with brain contusion and in 85 cases with brain concussion, and revealed that complaints and impaired adaptive functioning were frequent in both the contusion and concussion group. The occurrence of headache, dizziness and sleep problems did not significantly differ among the various head injury groups. However, focal or multifocal brain contusions on the CT scan increased the frequency of impaired memory, impaired concentration, speech problems, weakness in arms or legs and seizures with loss of consciousness. Cognitive deficits and speech problems were particularly common in patients with a focal contusion in the temporal lobe. The late adaptive and social functioning were most markedly impaired in cases with multifocal bilateral contusions.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Green, J; Leon-Barth, C; Dieter, J; Benfante, P; Walker, D
Somatosensory evoked responses via electronic brain imaging (EBI) Journal Article
In: Clinical Electroencephalography, vol. 23, pp. 79–88, 1992.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Green1992,
title = {Somatosensory evoked responses via electronic brain imaging (EBI)},
author = {Green, J and Leon-Barth, C and Dieter, J and Benfante, P and Walker, D},
year = {1992},
date = {1992-01-01},
journal = {Clinical Electroencephalography},
volume = {23},
pages = {79--88},
address = {Southeastern Neuroscience Institute, Inc., Jacksonville, FL 32207-6840.},
abstract = {This study of a series of 40 mildly head injured (concussed) patients suggests that different physiologic pathways underlying the tests done in a six-part resting EEG, and for the 11 evoked electrical potential shifts occurring in the cerebral terrain, are testable. Further work seems likely in order to ascertain which clinical signs and symptoms may be related to specific individual types of recorded electronic brain imaging (EBI) abnormality. Which of the 11 parameters studied, EEG, VER, AER, and SER, would be more or less likely to be abnormal in their individual patterns (as being deviant from normal controls) also remains to be defined. The relationship of these neurophysiologic abnormalities to certain postconcussive symptoms, i.e., headache, dizziness, blurred vision, etc., at this point in time remains to be evaluated more precisely. The authors suggest that further research is necessary in evaluating the clinical use of somatosensory evoked responses as an additional parameter in electronic brain imaging (EBI) technology.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Chong, C D; Schwedt, T J
White matter damage and brain network alterations in concussed patients: a review of recent diffusion tensor imaging and resting-state functional connectivity data Journal Article
In: Current Pain & Headache Reports, vol. 19, pp. 485, 2015.
@article{Chong2015,
title = {White matter damage and brain network alterations in concussed patients: a review of recent diffusion tensor imaging and resting-state functional connectivity data},
author = {Chong, C D and Schwedt, T J},
year = {2015},
date = {2015-01-01},
journal = {Current Pain \& Headache Reports},
volume = {19},
pages = {485},
address = {Chong,Catherine D. Department of Neurology, Mayo Clinic, 5777 East Mayo Boulevard, Phoenix, AZ, 85054, USA, Chong.catherine@mayo.edu.},
abstract = {Over 2 million people are diagnosed with concussion each year in the USA, resulting in substantial individual and societal burdens. Although 'routine' clinical neuroimaging is useful for the diagnosis of more severe forms of traumatic brain injury, it is insensitive for detecting pathology associated with concussion. Diffusion tensor imaging (DTI) and blood-oxygenation-level-dependent (BOLD) resting-state functional connectivity magnetic resonance imaging (rs-fMRI) are techniques that allow for investigation of brain structural and functional connectivity patterns. DTI and rs-fMRI may be more sensitive than routine neuroimaging for detecting brain sequelae of concussion. This review summarizes recent DTI and rs-fMRI findings of altered structural and functional connectivity patterns in concussed patients.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Murugavel, M; Cubon, V; Putukian, M; Echemendia, R; Cabrera, J; Osherson, D; Dettwiler, A
A longitudinal diffusion tensor imaging study assessing white matter fiber tracts after sports-related concussion Journal Article
In: Journal of Neurotrauma, vol. 31, pp. 1860–1871, 2014.
@article{Murugavel2014,
title = {A longitudinal diffusion tensor imaging study assessing white matter fiber tracts after sports-related concussion},
author = {Murugavel, M and Cubon, V and Putukian, M and Echemendia, R and Cabrera, J and Osherson, D and Dettwiler, A},
year = {2014},
date = {2014-01-01},
journal = {Journal of Neurotrauma},
volume = {31},
pages = {1860--1871},
address = {Murugavel,Murali. 1 Princeton Neuroscience Institute, Princeton University , Princeton New Jersey.},
abstract = {The extent of structural injury in sports-related concussion (SRC) is central to the course of recovery, long-term effects, and the decision to return to play. In the present longitudinal study, we used diffusion tensor imaging (DTI) to assess white matter (WM) fiber tract integrity within 2 days, 2 weeks, and 2 months of concussive injury. Participants were right-handed male varsity contact-sport athletes (20.2+/-1.0 years of age) with a medically diagnosed SRC (no loss of consciousness). They were compared to right-handed male varsity non-contact-sport athletes serving as controls (19.9+/-1.7 years). We found significantly increased radial diffusivity (RD) in concussed athletes (n=12; paired t-test, tract-based spatial statistics; p\<0.025) at 2 days, when compared to the 2-week postinjury time point. The increase was found in a cluster of right hemisphere voxels, spanning the posterior limb of the internal capsule (IC), the retrolenticular part of the IC, the inferior longitudinal fasciculus, the inferior fronto-occipital fasciculus (sagittal stratum), and the anterior thalamic radiation. Post-hoc, univariate, between-group (controls vs. concussed), mixed-effects analysis of the cluster showed significantly higher RD at 2 days (p=0.002), as compared to the controls, with a trend in the same direction at 2 months (p=0.11). Results for fractional anisotropy (FA) in the same cluster showed a similar, but inverted, pattern; FA was decreased at 2 days and at 2 months postinjury, when compared to healthy controls. At 2 weeks postinjury, no statistical differences between concussed and control athletes were found with regard to either RD or FA. These results support the hypothesis of increased RD and reduced FA within 72h postinjury, followed by recovery that may extend beyond 2 weeks. RD appears to be a sensitive measure of concussive injury.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Watts, R; Thomas, A; Filippi, C G; Nickerson, J P; Freeman, K
Potholes and molehills: bias in the diagnostic performance of diffusion-tensor imaging in concussion Journal Article
In: Radiology, vol. 272, pp. 217–223, 2014.
@article{Watts2014,
title = {Potholes and molehills: bias in the diagnostic performance of diffusion-tensor imaging in concussion},
author = {Watts, R and Thomas, A and Filippi, C G and Nickerson, J P and Freeman, K},
year = {2014},
date = {2014-01-01},
journal = {Radiology},
volume = {272},
pages = {217--223},
address = {From the Departments of Radiology (R.W., C.G.F., J.P.N.), Surgery (A.T., K.V.), and Neurology (C.G.F.), University of Vermont, Given Medical Building E301, 89 Beaumont Ave, Burlington, VT 05405.},
abstract = {Purpose To investigate the extent of bias in a clinical study involving "pothole analysis" of diffusion-tensor imaging (DTI) data used to quantify white matter lesion load in diseases with a heterogeneous spatial distribution of pathologic findings, such as mild traumatic brain injury (TBI), and create a mathematical model of the bias. Materials and Methods Use of the same reference population to define normal findings and make comparisons with a patient group introduces bias, which potentially inflates reported diagnostic performance. In this institutional review board-approved prospective observational cohort study, DTI data were obtained in 20 patients admitted to the emergency department with mild TBI and in 16 control subjects. Potholes and molehills were defined as clusters of voxels with fractional anisotropy values more than 2 standard deviations below and above the mean of the corresponding voxels in the reference population, respectively. The number and volume of potholes and molehills in the two groups were compared by using a Mann-Whitney U test. Results Standard analysis showed significantly more potholes in mild TBI than in the control group (102.5 + 34.3 vs 50.6 + 28.9, P \< .001). Repeat analysis by using leave-one-out cross-validation decreased the apparent difference in potholes between groups (mild TBI group, 102.5 + 34.3; control group, 93.4 + 27.2; P = .369). It was demonstrated that even with 100 subjects, this bias can decrease the voxelwise false-positive rate by more than 30% in the control group. Conclusion The pothole approach to neuroimaging data may introduce bias, which can be minimized by independent training and test groups or cross-validation methods. This bias is sufficient to call into question the previously reported diagnostic performance of DTI for mild TBI. RSNA, 2014 Online supplemental material is available for this article.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Lee, R R; Huang, M
Magnetoencephalography in the diagnosis of concussion Journal Article
In: Progress in Neurological Surgery, vol. 28, pp. 94–111, 2014.
@article{Lee2014,
title = {Magnetoencephalography in the diagnosis of concussion},
author = {Lee, R R and Huang, M},
year = {2014},
date = {2014-01-01},
journal = {Progress in Neurological Surgery},
volume = {28},
pages = {94--111},
address = {Department of Radiology, VA San Diego Healthcare System, and University of California, San Diego, San Diego, Calif., USA.},
abstract = {Magnetoencephalography (MEG) is a biomedical technique which measures the magnetic fields emitted by the brain, generated by neuronal activity. Commercial whole-head MEG units have been available for about 15 years, but currently there are only about 20 such units operating in the USA. Here, we review the basic concepts of MEG and list some of the usual clinical indications: noninvasive localization of epileptic spikes and presurgical mapping of eloquent cortex. We then discuss using MEG to diagnose mild traumatic brain injury (mTBI; concussions). Injured brain tissues in TBI patients generate abnormal low-frequency magnetic activity (delta-waves: 1-4 Hz) that can be measured and localized by MEG. These abnormal delta-waves originate from neurons that experience deafferentation from axonal injury to the associated white matter fiber tracts, also manifested on diffusion tensor imaging as reduced fractional anisotropy. Magnetoencephalographic evaluation of abnormal delta-waves (1-4 Hz) is probably the most sensitive objective test to diagnose concussions. An automated MEG low-frequency (slow wave) source imaging method, frequency-domain vector-based spatiotemporal analysis using a L1-minimum norm (VESTAL), achieved a positive finding rate of 87% for diagnosing concussions (blast-induced plus nonblast), 100% for moderate TBI, and no false-positive diagnoses in normal controls. There were also significant correlations between the number of cortical regions generating abnormal slow waves and the total postconcussive symptom scores in TBI patients. 2014 S. Karger AG, Basel.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Acocello, S; Broshek, D K; Saliba, S
Inter-rater and intra-rater reliability of cerebral blood flow measures obtained using the Brain Acoustic Monitor Journal Article
In: Journal of Neuroscience Methods, vol. 221, pp. 85–91, 2014.
@article{Acocello2014,
title = {Inter-rater and intra-rater reliability of cerebral blood flow measures obtained using the Brain Acoustic Monitor},
author = {Acocello, S and Broshek, D K and Saliba, S},
year = {2014},
date = {2014-01-01},
journal = {Journal of Neuroscience Methods},
volume = {221},
pages = {85--91},
address = {University of Virginia, Exercise and Sport Injury Laboratory, 210 Emmet Street South, PO Box 400407, Charlottesville, VA 22901, USA. Electronic address: ss9qb@virginia.edu.},
abstract = {BACKGROUND: Current assessment of sport-related concussion involves a multifaceted approach including neurocognitive testing, symptom report, and balance assessment. Lacking from this paradigm is a truly objective measure of the physiological changes associated with concussion. NEW METHOD: A device called the Brain Acoustic Monitor (BAM) has been developed to detect cerebral blood flow changes resulting from traumatic brain injury by amplification and comparison of sound waves created by cerebral arteries and a reference artery. The reliability of its measures is unknown, limiting its use in day-to-day assessment of concussion. Therefore, the purpose of this study was to determine the inter- and intra-rater reliability associated with BAM measures. Twenty healthy participants were assessed on two occasions, separated by at least 24h. Ten subjects were measured during the initial session by two assessors for inter-rater comparisons. Measures of positive-to-negative signal deflection (ratio) and frequency divergence from a reference arterial signal (divergence) were calculated and analyzed using Intra-class correlations (2,1). RESULTS: Inter-rater reliability ranged from poor to excellent, showing greater reliability in right brain vs. left brain measures. Intra-rater reliability was similar with a range of poor to good. COMPARISON WITH EXISTING METHODS: These findings are comparable to the reliability of current methods of concussion assessment, specifically neurocognitive testing. CONCLUSION: All BAM values obtained in our healthy subjects were well below scores that would reflect potential head injury. These findings emphasize the potential usefulness of this device in future research concerning serial measurement of cerebral perfusion pressure changes associated with sport concussion.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Johnson, B; Zhang, K; Gay, M; Neuberger, T; Horovitz, S; Hallett, M; Sebastianelli, W; Slobounov, S
Metabolic alterations in corpus callosum may compromise brain functional connectivity in MTBI patients: An H-1-MRS study Journal Article
In: Neuroscience Letters, vol. 509, pp. 5–8, 2012, ISSN: 0304-3940.
@article{Johnson2012b,
title = {Metabolic alterations in corpus callosum may compromise brain functional connectivity in MTBI patients: An H-1-MRS study},
author = {Johnson, B and Zhang, K and Gay, M and Neuberger, T and Horovitz, S and Hallett, M and Sebastianelli, W and Slobounov, S},
doi = {10.1016/j.neulet.2011.11.013},
issn = {0304-3940},
year = {2012},
date = {2012-01-01},
journal = {Neuroscience Letters},
volume = {509},
pages = {5--8},
abstract = {After clinical resolution of signs and symptoms of mild traumatic brain injury (MTBI) it is still not clear if there are residual abnormalities of structural or functional brain networks. We have previously documented disrupted interhemispheric functional connectivity in 'asymptomatic' concussed individuals during the sub-acute phase of injury. Testing of 15 normal volunteers (NV) and 15 subacute MTBI subjects was performed within 24 h of clinical symptoms resolution and medical clearance for the first stage of aerobic activity. In this MRS study we report: (a) both in the genu and splenium of the corpus callosum NAA/Cho and NAA/Cr ratios were significantly (p \< 0.05) lower in MTBI subjects shortly after the injury compared to NVs, and (b) the metabolic ratio NAA/Cho in the splenium significantly correlated with the magnitude of inter-hippocampal functional connectivity in normal volunteers, but not in MTBI. This novel finding supports our hypothesis that the functional disruption of interhemispheric brain networks in MTBI subjects results from compromised metabolic integrity of the corpus callosum and that this persists despite apparent clinical return to baseline.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Lin, A P; Liao, H J; Merugumala, S K; Prabhu, S P; Meehan, W P; Ross, B D
Metabolic imaging of mild traumatic brain injury Journal Article
In: Brain Imaging and Behavior, vol. 6, pp. 208–223, 2012.
@article{Lin2012,
title = {Metabolic imaging of mild traumatic brain injury},
author = {Lin, A P and Liao, H J and Merugumala, S K and Prabhu, S P and Meehan, W P and Ross, B D},
doi = {10.1007/s11682-012-9181-4},
year = {2012},
date = {2012-01-01},
journal = {Brain Imaging and Behavior},
volume = {6},
pages = {208--223},
abstract = {Traumatic brain injury results in a metabolic cascade of changes that occur at the molecular level, invisible to conventional imaging methods such as computed tomography or magnetic resonance imaging. Non-invasive metabolic imaging tools such as single photon emission computed tomography (SPECT), positron emission tomography (PET), and magnetic resonance spectroscopy (MRS) are the ideal methods for providing insight to these changes by measuring regional cerebral blood flow, glucose metabolism, and brain metabolite concentrations, respectively, after mild traumatic brain injury (mTBI). The purpose of this review is to provide an overview of the different methodologies and provide an up-to-date summary of recent findings with SPECT, PET, and MRS technologies, specifically after mTBI, as defined by standardized criteria. Given that the different physiological and pathological responses are heterogeneous, efforts will be made to separate studies at different time points after injury (acute, subacute, and chronic stages) as well as to the different types of mTBI such sports-related head injury where repetitive head injuries are much more common and may present a unique signature.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Tang, L; Ge, Y L; Sodickson, D K; Miles, L; Zhou, Y X; Reaume, J; Grossman, R I
Thalamic resting-state functional networks: Disruption in patients with mild traumatic brain injury Journal Article
In: Radiology, vol. 260, pp. 831–840, 2011, ISSN: 0033-8419.
@article{Tang2011,
title = {Thalamic resting-state functional networks: Disruption in patients with mild traumatic brain injury},
author = {Tang, L and Ge, Y L and Sodickson, D K and Miles, L and Zhou, Y X and Reaume, J and Grossman, R I},
doi = {10.1148/radiol.11110014},
issn = {0033-8419},
year = {2011},
date = {2011-01-01},
journal = {Radiology},
volume = {260},
pages = {831--840},
abstract = {Purpose: To explore the neural correlates of the thalamus by using resting-state functional magnetic resonance (MR) imaging and to investigate whether thalamic resting-state networks (RSNs) are disrupted in patients with mild traumatic brain injury (MTBI). Materials and Methods: This HIPAA-compliant study was approved by the institutional review board, and written informed consent was obtained from 24 patients with MTBI and 17 healthy control subjects. The patients had varying degrees of symptoms, with a mean disease duration of 22 days. The resting-state functional MR imaging data were analyzed by using a standard seed-based whole-brain correlation method to characterize thalamic RSNs. Student t tests were used to perform comparisons. The association between thalamic RSNs and performance on neuropsychologic and neurobehavioral measures was also investigated in patients with MTBI by using Spearman rank correlation. Results: A normal pattern of thalamic RSNs was demonstrated in healthy subjects. This pattern was characterized as representing relatively symmetric and restrictive functional thalamocortical connectivity, suggesting an inhibitory property of the thalamic neurons during the resting state. This pattern was disrupted, with significantly increased thalamic RSNs (P \<= .005) and decreased symmetry (P = .03) in patients with MTBI compared with healthy control subjects. Increased functional thalamocortical redistributive connectivity was correlated with diminished neurocognitive functions and clinical symptoms in patients with MTBI. Conclusion: These findings of abnormal thalamic RSNs lend further support to the presumed subtle thalamic injury in patients with MTBI. Resting-state functional MR imaging can be used as an additional imaging modality for detection of thalamocortical connectivity abnormalities and for better understanding of the complex persistent postconcussive syndrome. (C) RSNA, 2011},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Unden, Johan; Romner, Bertil
Can low serum levels of S100B predict normal CT findings after minor head injury in adults?: an evidence-based review and meta-analysis Journal Article
In: Journal of Head Trauma Rehabilitation, vol. 25, pp. 228–240, 2010.
@article{Unden2010,
title = {Can low serum levels of S100B predict normal CT findings after minor head injury in adults?: an evidence-based review and meta-analysis},
author = {Unden, Johan and Romner, Bertil},
year = {2010},
date = {2010-01-01},
journal = {Journal of Head Trauma Rehabilitation},
volume = {25},
pages = {228--240},
address = {Department of Anaesthesia and Intensive Care, Halmstad Regional Hospital, Halmstad, Sweden. johan.unden@Ithalland.se},
abstract = {OBJECTIVE: To determine whether low levels of S100B in serum can predict normal computed tomography (CT) findings after minor head injury (MHI) in adults. PARTICIPANTS: Not applicable. DESIGN: Systematic evidence-based review of the peer-reviewed literature with meta-analytical interpretation. PRIMARY MEASURES: Not applicable. RESULTS: We identified 12 eligible articles that specifically studied adult MHI patients with S100B and cranial CT scans in the acute phase after injury, comprising a total of 2466 separate patients. Individual negative predictive values of 90% to 100% were found for the ability of a negative (under cutoff) S100B level to predict a normal CT scan. A total of 6 patients included in the studies had low S100B levels and positive CT scans (0.26%) and only 1 of these patients (0.04%) had a clinically relevant CT finding. The pooled negative predictive value for all studies was more than 99% (95% CI 98%-100%), with an average prevalence for any CT finding at 8%. The studies are consistently classed as level 2 and level 3 grades of evidence, suggesting a grade B recommendation. CONCLUSION: Low serum S100B levels accurately predict normal CT findings after MHI in adults. S100B sampling should be considered in MHI patients with no focal neurological deficit, an absence of significant extracerebral injury, should be taken within 3 hours of injury, and the cutoff for omitting CT set at less than 0.10 microg/L. Care givers should also be aware of other clinical factors predictive of intracranial complications after MHI.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Wu, Trevor C; Wilde, Elisabeth A; Bigler, Erin D; Yallampalli, Ragini; McCauley, Stephen R; Troyanskaya, Maya; Chu, Zili; Li, Xiaoqi; Hanten, Gerri; Hunter, Jill V; Levin, Harvey S
Evaluating the relationship between memory functioning and cingulum bundles in acute mild traumatic brain injury using diffusion tensor imaging Journal Article
In: Journal of Neurotrauma, vol. 27, pp. 303–307, 2010.
@article{Wu2010,
title = {Evaluating the relationship between memory functioning and cingulum bundles in acute mild traumatic brain injury using diffusion tensor imaging},
author = {Wu, Trevor C and Wilde, Elisabeth A and Bigler, Erin D and Yallampalli, Ragini and McCauley, Stephen R and Troyanskaya, Maya and Chu, Zili and Li, Xiaoqi and Hanten, Gerri and Hunter, Jill V and Levin, Harvey S},
year = {2010},
date = {2010-01-01},
journal = {Journal of Neurotrauma},
volume = {27},
pages = {303--307},
address = {Department of Psychology, Brigham Young University, Provo, Utah, USA.},
abstract = {Compromised memory functioning is one of the commonly reported cognitive sequelae seen following mild traumatic brain injury (mTBI). Diffusion tensor imaging (DTI) has been shown to be sufficiently sensitive at detecting early microstructural pathological alterations after mTBI. Given its location and shape, the cingulate, which is comprised of the cingulate gyrus (gray matter) and cingulum bundles (white matter), is selectively vulnerable to mTBI. In this study we examined the integrity of cingulum bundles using DTI, and the relationship between cingulum bundles and memory functioning. Twelve adolescents with mTBI and 11 demographically-matched healthy controls were studied. All participants with mTBI had a Glasgow Coma Scale score of 15, and were without intracranial findings on CT scan. Brain scans were performed on average 2.92 days post-injury, and all participants were administered the Verbal Selective Reminding Test (VSRT), an episodic verbal learning and memory task. Participants with mTBI had a significantly lower apparent diffusion coefficient (ADC) bilaterally than controls (p \< 0.001). Despite the marginal significance of the group difference in fractional anisotropy (FA), the effect size between groups was moderate (d = 0.66). Cognitively, healthy controls performed better than the TBI group on immediate and delayed recall; however, the difference did not reach statistical significance. In the mTBI group, FA of the left cingulum bundle was significantly correlated with 30-min delayed recall (r = -0.56},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Stulemeijer, M; Vos, P E; van der Werf, S; van Dijk, G; Rijpkema, M; Fernandez, G
How mild traumatic brain injury may affect declarative memory performance in the post-acute stage Journal Article
In: Journal of Neurotrauma, vol. 27, pp. 1585–1595, 2010, ISSN: 0897-7151.
@article{Stulemeijer2010,
title = {How mild traumatic brain injury may affect declarative memory performance in the post-acute stage},
author = {Stulemeijer, M and Vos, P E and van der Werf, S and van Dijk, G and Rijpkema, M and Fernandez, G},
doi = {10.1089/neu.2010.1298},
issn = {0897-7151},
year = {2010},
date = {2010-01-01},
journal = {Journal of Neurotrauma},
volume = {27},
pages = {1585--1595},
abstract = {Memory deficits are among the most frequently reported sequelae of mild traumatic brain injury (MTBI), especially early after injury. To date, these cognitive deficits remain poorly understood, as in most patients the brain is macroscopically intact. To identify the mechanism by which MTBI causes declarative memory impairments, we probed the functionality of the medial temporal lobe (MTL) and the prefrontal cortex (PFC), within 6 weeks after injury in 43 patients from a consecutive cohort, and matched healthy controls. In addition to neuropsychological measures of declarative memory and other cognitive domains, all subjects underwent functional magnetic resonance imaging (fMRI). Behavioral results showed poorer declarative memory performance in patients than controls, and decreasing performance with increasing duration of post-traumatic amnesia (a measure of injury severity). Task performance in the scanner was, as intended by the task and design, similar in patients and controls, and did not relate to injury severity. The task used reliably activated the MTL and PFC. Although we did not find significant differences in brain activity when comparing patients and controls, we revealed, in agreement with our neuropsychological findings, an inverse correlation between MTL activity and injury severity. In contrast, no difference in prefrontal activation was found between patients and controls, nor was there a relation with injury severity. On a behavioral level, injury severity was inversely related to declarative memory performance. In all, these findings suggest that reduced medial temporal functionality may contribute to poorer declarative memory performance in the post-acute stage of MTBI, especially in patients with longer post-traumatic amnesia.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Govind, Varan; Gold, Stuart; Kaliannan, Krithica; Saigal, Gaurav; Falcone, Steven; Arheart, Kristopher L; Harris, Leo; Jagid, Jonathan; Maudsley, Andrew A
Whole-brain proton MR spectroscopic imaging of mild-to-moderate traumatic brain injury and correlation with neuropsychological deficits Journal Article
In: Journal of Neurotrauma, vol. 27, pp. 483–496, 2010.
@article{Govind2010,
title = {Whole-brain proton MR spectroscopic imaging of mild-to-moderate traumatic brain injury and correlation with neuropsychological deficits},
author = {Govind, Varan and Gold, Stuart and Kaliannan, Krithica and Saigal, Gaurav and Falcone, Steven and Arheart, Kristopher L and Harris, Leo and Jagid, Jonathan and Maudsley, Andrew A},
year = {2010},
date = {2010-01-01},
journal = {Journal of Neurotrauma},
volume = {27},
pages = {483--496},
address = {Department of Radiology, University of Miami School of Medicine, Miami, Florida 33136, USA. VGovind@med.miami.edu},
abstract = {Changes in the distribution of the magnetic resonance (MR)-observable brain metabolites N-acetyl aspartate (NAA), total choline (Cho), and total creatine (Cre), following mild-to-moderate closed-head traumatic brain injury (mTBI) were evaluated using volumetric proton MR spectroscopic imaging (MRSI). Studies were carried out during the subacute time period following injury, and associations of metabolite indices with neuropsychological test (NPT) results were evaluated. Twenty-nine subjects with mTBI and Glasgow Coma Scale (GCS) scores of 10-15 were included. Differences in individual metabolite and metabolite ratio distributions relative to those of age-matched control subjects were evaluated, as well as analyses by hemispheric lobes and tissue types. Primary findings included a widespread decrease of NAA and NAA/Cre, and increases of Cho and Cho/NAA, within all lobes of the TBI subject group, and with the largest differences seen in white matter. Examination of the association between all of the metabolite measures and the NPT scores found the strongest negative correlations to occur in the frontal lobe and for Cho/NAA. No significant correlations were found between any of the MRSI or NPT measures and the GCS. These results demonstrate that significant and widespread alterations of brain metabolites occur as a result of mild-to-moderate TBI, and that these measures correlate with measures of cognitive performance.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Gasparovic, Charles; Yeo, Ronald; Mannell, Maggie; Ling, Josef; Elgie, Robert; Phillips, John; Doezema, David; Mayer, Andrew R
Neurometabolite concentrations in gray and white matter in mild traumatic brain injury: an 1H-magnetic resonance spectroscopy study Journal Article
In: Journal of Neurotrauma, vol. 26, pp. 1635–1643, 2009.
@article{Gasparovic2009,
title = {Neurometabolite concentrations in gray and white matter in mild traumatic brain injury: an 1H-magnetic resonance spectroscopy study},
author = {Gasparovic, Charles and Yeo, Ronald and Mannell, Maggie and Ling, Josef and Elgie, Robert and Phillips, John and Doezema, David and Mayer, Andrew R},
year = {2009},
date = {2009-01-01},
journal = {Journal of Neurotrauma},
volume = {26},
pages = {1635--1643},
address = {The Mind Research Network, Albuquerque, New Mexico 7131, USA. chuck@unm.edu},
abstract = {Single-voxel proton magnetic resonance imaging ((1)H-MRS) and proton MR spectroscopic imaging ((1)H-MRSI) were used to compare brain metabolite levels in semi-acute mild traumatic brain injury (mTBI) patients (n = 10) and matched healthy controls (n = 9). The (1)H-MRS voxel was positioned in the splenium, a region known to be susceptible to axonal injury in TBI, and a single (1)H-MRSI slice was positioned above the lateral ventricles. To increase sensitivity to the glutamate (Glu) and the combined glutamate-glutamine (Glx) signal, an inter-pulse echo time shown to emphasize the major Glu signals was used along with an analysis method that reduces partial volume errors by using water as a concentration standard. Our preliminary findings indicate significantly lower levels of gray matter Glx and higher levels of white matter creatine-phosphocreatine (Cr) in mTBI subjects relative to healthy controls. Furthermore, Cr levels were predictive of executive function and emotional distress in the combined groups. These results suggest that perturbations in Cr, a critical component of the brain's energy metabolism, and Glu, the brain's major neurotransmitter, may occur following mTBI. Moreover, the different pattern of results for gray and white matter suggests tissue-specific metabolic responses to mTBI.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Ruan, Shuolun; Noyes, Katia; Bazarian, Jeffrey J
The economic impact of S-100B as a pre-head CT screening test on emergency department management of adult patients with mild traumatic brain injury Journal Article
In: Journal of Neurotrauma, vol. 26, pp. 1655–1664, 2009.
@article{Ruan2009,
title = {The economic impact of S-100B as a pre-head CT screening test on emergency department management of adult patients with mild traumatic brain injury},
author = {Ruan, Shuolun and Noyes, Katia and Bazarian, Jeffrey J},
year = {2009},
date = {2009-01-01},
journal = {Journal of Neurotrauma},
volume = {26},
pages = {1655--1664},
address = {Department of Community and Preventive Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA. shuolun.ruan@aya.yale.edu},
abstract = {Recent research suggests that serum S-100B may serve as a good pre-head computed tomography (CT) screening test because of its high sensitivity for abnormal head CT scans. The potential economic impact of using S-100B in the emergency department setting for management of adult patients with isolated mild traumatic brain injury (mTBI) has not been evaluated despite its clinical implementation in Europe. Using evidence from the literature, we constructed a decision tree to compare the average cost per patient of using S-100B as a pre-head CT screening test to the current practice of ordering CT scans based on patients' presenting symptoms without the aid of S-100B. When compared to scanning 45-77% of isolated mTBI patients based upon their presenting symptoms, using S-100B as a pre-head CT screen does not lower hospital costs ($281 versus $160), primarily due to its low specificity for abnormal head CT scans. Sensitivity analyses showed, however, that S-100B becomes cost-lowering when the proportion of mTBI patients being scanned exceeds 78%, or when final CT scan results require 96 min or more than the wait for blood test results. Generally speaking, if blood test results require less time than imaging, and if head CT scan rates for patients with isolated mTBI are relatively high, using S-100B will lower costs. Recommendations for using S-100B as a screening tool should account for setting-specific characteristics and their consequent economic impacts. Despite its high sensitivity and excellent negative predictive value, serum S-100B has low specificity and low positive predictive value, limiting its ability to reduce numbers of CT scans and hospital costs.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Chen, Jen Kai; Johnston, Karen M; Petrides, Michael; Ptito, Alain
Recovery from mild head injury in sports: evidence from serial functional magnetic resonance imaging studies in male athletes Journal Article
In: Clinical Journal of Sport Medicine, vol. 18, pp. 241–247, 2008.
@article{Chen2008a,
title = {Recovery from mild head injury in sports: evidence from serial functional magnetic resonance imaging studies in male athletes},
author = {Chen, Jen Kai and Johnston, Karen M and Petrides, Michael and Ptito, Alain},
year = {2008},
date = {2008-01-01},
journal = {Clinical Journal of Sport Medicine},
volume = {18},
pages = {241--247},
address = {Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.},
abstract = {OBJECTIVE: To examine functional brain activation patterns before and after postconcussive symptoms (PCS) resolution. DESIGN: Prospective serial study with male athletes using functional magnetic resonance imaging (fMRI). SETTING: Hospital laboratory and imaging facility. PARTICIPANTS: 9 symptomatic concussed athletes who experienced persisting PCS at least 1 month postinjury and 6 healthy athletes. INTERVENTIONS: All athletes filled out a PCS checklist and underwent an fMRI session during which they performed a working-memory task. MAIN OUTCOME MEASUREMENTS: Behavioral outcomes were response speed and accuracy on the working memory tasks performed during the fMRI session. Functional imaging outcomes were blood oxygen level-dependent fMRI activation patterns associated with a working memory task. RESULTS:: There was no difference in behavioral performance between the groups. Despite normal structural MRI findings, all symptomatic concussed athletes initially showed atypical brain activation patterns in the dorsolateral prefrontal cortex (DLPC). Compared to the initial postinjury evaluation, those athletes at follow-up with PCS resolved showed significant increases in activation in the left DLPC. Concussed athletes whose PCS status remained unchanged at follow-up continued to show atypical activation in DLPC. Healthy athletes showed remarkably clear and consistent brain activations in DLPC initially as well as in follow-up, highlighting the test-retest reliability of fMRI. CONCLUSIONS: The results demonstrate the feasibility of using fMRI to detect an underlying pathology in symptomatic concussed athletes with normal structural imaging results and its potential to document recovery. Such information may be of considerable value for clinical judgment and patient management.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Ptito, Alain; Chen, Jen-Kai; Johnston, Karen M
Contributions of functional magnetic resonance imaging (fMRI) to sport concussion evaluation Journal Article
In: NeuroRehabilitation, vol. 22, pp. 217–227, 2007.
@article{Ptito2007,
title = {Contributions of functional magnetic resonance imaging (fMRI) to sport concussion evaluation},
author = {Ptito, Alain and Chen, Jen-Kai and Johnston, Karen M},
year = {2007},
date = {2007-01-01},
journal = {NeuroRehabilitation},
volume = {22},
pages = {217--227},
address = {Montreal Neurological Institute McGill University, Montreal, Quebec, Canada. alain.ptito@mcgill.ca},
abstract = {Mild traumatic brain injury (mTBI) in contact sport is a problem of such magnitude that improved approaches to diagnosis, investigation and management are urgent. Concussion has traditionally been described as a transient, fully reversible, cerebral dysfunction. However, this seemingly 'mild' injury sometimes results in long-lasting and disabling post-concussion symptoms (PCS) and abnormal neuropsychological profiles characteristic of frontal and/or temporal lobe dysfunction. At present, the pathological changes following concussion remain unclear, but it is now widely accepted that concussion results mainly in functional disturbance rather than structural damage. Therefore, functional imaging techniques can help in demonstrating brain abnormalities undetectable by structural imaging methods. This paper will review the use of functional magnetic resonance imaging (fMRI) in studies of concussion. Our existing and ongoing fMRI studies will be described as examples to highlight the potential and contribution of this non-invasive functional neuroimaging technique in the assessment of sports-related concussion and its management. [References: 54]},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Kirov, Ivan; Fleysher, Lazar; Babb, James S; Silver, Jonathan M; Grossman, Robert I; Gonen, Oded
Characterizing 'mild' in traumatic brain injury with proton MR spectroscopy in the thalamus: Initial findings Journal Article
In: Brain Injury, vol. 21, pp. 1147–1154, 2007.
@article{Kirov2007,
title = {Characterizing 'mild' in traumatic brain injury with proton MR spectroscopy in the thalamus: Initial findings},
author = {Kirov, Ivan and Fleysher, Lazar and Babb, James S and Silver, Jonathan M and Grossman, Robert I and Gonen, Oded},
year = {2007},
date = {2007-01-01},
journal = {Brain Injury},
volume = {21},
pages = {1147--1154},
address = {Department of Radiology, New York, USA.},
abstract = {OBJECTIVE: Although most mild traumatic brain injury (mTBI) patients suffer any of several post-concussion symptoms suggestive of thalamic involvement, they rarely present with any MRI-visible pathology. The aim here, therefore, is to characterize their thalamic metabolite levels with proton MR spectroscopy (1H-MRS) compared with healthy controls. METHODS: T1-weighted MRI and multi-voxel 1H-MRS were acquired at 3 Tesla from 20 mTBI (Glasgow Coma Scale score of 15-13) patients, 19-59 years old, 0-7 years post-injury; and from 17 age and gender matched healthy controls. Mixed model regression was used to compare patients and controls with respect to the mean absolute N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) levels within each thalamus. RESULTS: The mTBI-induced thalamic metabolite concentration changes were under +/- 13.0% for NAA, +/- 13.5% for Cr and +/- 18.8% for Cho relative to their corresponding concentrations in the controls: NAA: 10.08 +/- 0.30 (mean +/- standard error), Cr: 5.62 +/- 0.18 and Cho: 2.08 +/- 0.09 mM. These limits represent the minimal detectable differences between the two cohorts. CONCLUSION: The change in metabolic levels in the thalamus of patients who sustained clinically defined mTBI could be an instrumental characteristic of 'mildness'. 1H-MRS could, therefore, serve as an objective laboratory indicator for differentiating 'mild' from more severe categories of head-trauma, regardless of the presence or lack of current clinical symptoms.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Kraus, Marilyn F; Susmaras, Teresa; Caughlin, Benjamin P; Walker, Corey J; Sweeney, John A; Little, Deborah M
White matter integrity and cognition in chronic traumatic brain injury: a diffusion tensor imaging study Journal Article
In: Brain, vol. 130, pp. 2508–2519, 2007.
@article{Kraus2007,
title = {White matter integrity and cognition in chronic traumatic brain injury: a diffusion tensor imaging study},
author = {Kraus, Marilyn F and Susmaras, Teresa and Caughlin, Benjamin P and Walker, Corey J and Sweeney, John A and Little, Deborah M},
year = {2007},
date = {2007-01-01},
journal = {Brain},
volume = {130},
pages = {2508--2519},
address = {Department of Psychiatry, University of Illinois at Chicago Medical Center, Chicago, IL, USA. mkraus@psych.uic.edu},
abstract = {Traumatic brain injury (TBI) is a serious public health problem. Even injuries classified as mild, the most common, can result in persistent neurobehavioural impairment. Diffuse axonal injury is a common finding after TBI, and is presumed to contribute to outcomes, but may not always be apparent using standard neuroimaging. Diffusion tensor imaging (DTI) is a more recent method of assessing axonal integrity in vivo. The primary objective of the current investigation was to characterize white matter integrity utilizing DTI across the spectrum of chronic TBI of all severities. A secondary objective was to examine the relationship between white matter integrity and cognition. Twenty mild, 17 moderate to severe TBI and 18 controls underwent DTI and neuropsychological testing. Fractional anisotropy, axial diffusivity and radial diffusivity were calculated from the DTI data. Fractional anisotropy was the primary measure of white matter integrity. Region of interest analysis included anterior and posterior corona radiata, cortico-spinal tracts, cingulum fibre bundles, external capsule, forceps minor and major, genu, body and splenium of the corpus callosum, inferior fronto-occipital fasciculus, superior longitudinal fasciculus and sagittal stratum. Cognitive domain scores were calculated from executive, attention and memory testing. Decreased fractional anisotropy was found in all 13 regions of interest for the moderate to severe TBI group, but only in the cortico-spinal tract, sagittal stratum and superior longitudinal fasciculus for the mild TBI group. White Matter Load (a measure of the total number of regions with reduced FA) was negatively correlated with all cognitive domains. Analysis of radial and axial diffusivity values suggested that all severities of TBI can result in a degree of axonal damage, while irreversible myelin damage was only apparent for moderate to severe TBI. The present data emphasize that white matter changes exist on a spectrum, including mild TBI. An index of global white matter neuropathology (White Matter Load) was related to cognitive function, such that greater white matter pathology predicted greater cognitive deficits. Mechanistically, mild TBI white matter changes may be primarily due to axonal damage as opposed to myelin damage. The more severe injuries impact both. DTI provides an objective means for determining the relationship of cognitive deficits to TBI, even in cases where the injury was sustained years prior to the evaluation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Bazarian, Jeffrey J; Blyth, Brian; Cimpello, Lynn
Bench to bedside: evidence for brain injury after concussion--looking beyond the computed tomography scan Journal Article
In: Academic Emergency Medicine, vol. 13, pp. 199–214, 2006.
@article{Bazarian2006a,
title = {Bench to bedside: evidence for brain injury after concussion--looking beyond the computed tomography scan},
author = {Bazarian, Jeffrey J and Blyth, Brian and Cimpello, Lynn},
year = {2006},
date = {2006-01-01},
journal = {Academic Emergency Medicine},
volume = {13},
pages = {199--214},
address = {Department of Emergency Medicine, Strong Memorial Hospital, University of Rochester, Rochester, NY 14642, USA. jeff_bazarian@urmc.rochester.edu},
abstract = {The emergency management of cerebral concussion typically centers on the decision to perform a head computed tomography (CT) scan, which only rarely detects hemorrhagic lesions requiring neurosurgery. The absence of hemorrhage on CT scan often is equated with a lack of brain injury. However, observational studies revealing poor long-term cognitive outcome after concussion suggest that brain injury may be present despite a normal CT scan. To explore this idea further, the authors reviewed the evidence for objective neurologic injury in humans after concussion, with particular emphasis on those with a normal brain CT. This evidence comes from studies involving brain tissue pathology, CT scanning, magnetic resonance image (MRI) scanning, serum biomarkers, formal cognitive and balance tests, functional MRI, positron emission tomography, and single-photon emission computed tomography scanning. Each section is accompanied by technical information to help the reader understand what these tests are, not to endorse their use clinically. The authors discuss the strengths and weaknesses of the evidence in each case. These reports make a compelling case for the existence of concussion as a clinically relevant disease with demonstrable neurologic pathology. Areas for future emergency medicine research are suggested. [References: 169]},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Chappell, M H; Ulug, A M; Zhang, L; Heitger, M H; Jordan, B D; Zimmerman, R D; Watts, R
Distribution of microstructural damage in the brains of professional boxers: A diffusion MRI study Journal Article
In: Journal of Magnetic Resonance Imaging, vol. 24, pp. 537–542, 2006, ISSN: 1053-1807.
@article{Chappell2006,
title = {Distribution of microstructural damage in the brains of professional boxers: A diffusion MRI study},
author = {Chappell, M H and Ulug, A M and Zhang, L and Heitger, M H and Jordan, B D and Zimmerman, R D and Watts, R},
doi = {10.1002/jmri.20656},
issn = {1053-1807},
year = {2006},
date = {2006-01-01},
journal = {Journal of Magnetic Resonance Imaging},
volume = {24},
pages = {537--542},
abstract = {Purpose: To investigate and localize cerebral abnormalities in professional boxers with no history of moderate or severe head trauma. Materials and Methods: Diffusion tensor imaging (DTI) was used to determine the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in the brains of 81 professional male boxers and 12 male control subjects. Voxel-based analysis (VBA) of both the diffusion and anisotropy values was performed using statistical parametric mapping (SPM). From this objective analysis, regions of microstructural abnormalities in the brains of the boxers were located. Results: Increases in the ADC, and decreases in FA were identified in deep white matter (WM), while decreases in ADC were identified in cortical gray matter (GM). Regions of positive correlation between ADC and age were also found in both the boxer and control groups, although the regions and strength of the correlation were not the same in each group. Conclusion: Using VBA, we localized previously unreported abnormalities in the brains of professional boxers. These abnormalities are assumed to reflect cumulative (chronic) brain injury resulting from nonsevere head trauma.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Chong, C D; Schwedt, T J
White matter damage and brain network alterations in concussed patients: a review of recent diffusion tensor imaging and resting-state functional connectivity data Journal Article
In: Current Pain & Headache Reports, vol. 19, pp. 485, 2015.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Chong2015,
title = {White matter damage and brain network alterations in concussed patients: a review of recent diffusion tensor imaging and resting-state functional connectivity data},
author = {Chong, C D and Schwedt, T J},
year = {2015},
date = {2015-01-01},
journal = {Current Pain \& Headache Reports},
volume = {19},
pages = {485},
address = {Chong,Catherine D. Department of Neurology, Mayo Clinic, 5777 East Mayo Boulevard, Phoenix, AZ, 85054, USA, Chong.catherine@mayo.edu.},
abstract = {Over 2 million people are diagnosed with concussion each year in the USA, resulting in substantial individual and societal burdens. Although 'routine' clinical neuroimaging is useful for the diagnosis of more severe forms of traumatic brain injury, it is insensitive for detecting pathology associated with concussion. Diffusion tensor imaging (DTI) and blood-oxygenation-level-dependent (BOLD) resting-state functional connectivity magnetic resonance imaging (rs-fMRI) are techniques that allow for investigation of brain structural and functional connectivity patterns. DTI and rs-fMRI may be more sensitive than routine neuroimaging for detecting brain sequelae of concussion. This review summarizes recent DTI and rs-fMRI findings of altered structural and functional connectivity patterns in concussed patients.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Murugavel, M; Cubon, V; Putukian, M; Echemendia, R; Cabrera, J; Osherson, D; Dettwiler, A
A longitudinal diffusion tensor imaging study assessing white matter fiber tracts after sports-related concussion Journal Article
In: Journal of Neurotrauma, vol. 31, pp. 1860–1871, 2014.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Murugavel2014,
title = {A longitudinal diffusion tensor imaging study assessing white matter fiber tracts after sports-related concussion},
author = {Murugavel, M and Cubon, V and Putukian, M and Echemendia, R and Cabrera, J and Osherson, D and Dettwiler, A},
year = {2014},
date = {2014-01-01},
journal = {Journal of Neurotrauma},
volume = {31},
pages = {1860--1871},
address = {Murugavel,Murali. 1 Princeton Neuroscience Institute, Princeton University , Princeton New Jersey.},
abstract = {The extent of structural injury in sports-related concussion (SRC) is central to the course of recovery, long-term effects, and the decision to return to play. In the present longitudinal study, we used diffusion tensor imaging (DTI) to assess white matter (WM) fiber tract integrity within 2 days, 2 weeks, and 2 months of concussive injury. Participants were right-handed male varsity contact-sport athletes (20.2+/-1.0 years of age) with a medically diagnosed SRC (no loss of consciousness). They were compared to right-handed male varsity non-contact-sport athletes serving as controls (19.9+/-1.7 years). We found significantly increased radial diffusivity (RD) in concussed athletes (n=12; paired t-test, tract-based spatial statistics; p\<0.025) at 2 days, when compared to the 2-week postinjury time point. The increase was found in a cluster of right hemisphere voxels, spanning the posterior limb of the internal capsule (IC), the retrolenticular part of the IC, the inferior longitudinal fasciculus, the inferior fronto-occipital fasciculus (sagittal stratum), and the anterior thalamic radiation. Post-hoc, univariate, between-group (controls vs. concussed), mixed-effects analysis of the cluster showed significantly higher RD at 2 days (p=0.002), as compared to the controls, with a trend in the same direction at 2 months (p=0.11). Results for fractional anisotropy (FA) in the same cluster showed a similar, but inverted, pattern; FA was decreased at 2 days and at 2 months postinjury, when compared to healthy controls. At 2 weeks postinjury, no statistical differences between concussed and control athletes were found with regard to either RD or FA. These results support the hypothesis of increased RD and reduced FA within 72h postinjury, followed by recovery that may extend beyond 2 weeks. RD appears to be a sensitive measure of concussive injury.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Watts, R; Thomas, A; Filippi, C G; Nickerson, J P; Freeman, K
Potholes and molehills: bias in the diagnostic performance of diffusion-tensor imaging in concussion Journal Article
In: Radiology, vol. 272, pp. 217–223, 2014.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Watts2014,
title = {Potholes and molehills: bias in the diagnostic performance of diffusion-tensor imaging in concussion},
author = {Watts, R and Thomas, A and Filippi, C G and Nickerson, J P and Freeman, K},
year = {2014},
date = {2014-01-01},
journal = {Radiology},
volume = {272},
pages = {217--223},
address = {From the Departments of Radiology (R.W., C.G.F., J.P.N.), Surgery (A.T., K.V.), and Neurology (C.G.F.), University of Vermont, Given Medical Building E301, 89 Beaumont Ave, Burlington, VT 05405.},
abstract = {Purpose To investigate the extent of bias in a clinical study involving "pothole analysis" of diffusion-tensor imaging (DTI) data used to quantify white matter lesion load in diseases with a heterogeneous spatial distribution of pathologic findings, such as mild traumatic brain injury (TBI), and create a mathematical model of the bias. Materials and Methods Use of the same reference population to define normal findings and make comparisons with a patient group introduces bias, which potentially inflates reported diagnostic performance. In this institutional review board-approved prospective observational cohort study, DTI data were obtained in 20 patients admitted to the emergency department with mild TBI and in 16 control subjects. Potholes and molehills were defined as clusters of voxels with fractional anisotropy values more than 2 standard deviations below and above the mean of the corresponding voxels in the reference population, respectively. The number and volume of potholes and molehills in the two groups were compared by using a Mann-Whitney U test. Results Standard analysis showed significantly more potholes in mild TBI than in the control group (102.5 + 34.3 vs 50.6 + 28.9, P \< .001). Repeat analysis by using leave-one-out cross-validation decreased the apparent difference in potholes between groups (mild TBI group, 102.5 + 34.3; control group, 93.4 + 27.2; P = .369). It was demonstrated that even with 100 subjects, this bias can decrease the voxelwise false-positive rate by more than 30% in the control group. Conclusion The pothole approach to neuroimaging data may introduce bias, which can be minimized by independent training and test groups or cross-validation methods. This bias is sufficient to call into question the previously reported diagnostic performance of DTI for mild TBI. RSNA, 2014 Online supplemental material is available for this article.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Lee, R R; Huang, M
Magnetoencephalography in the diagnosis of concussion Journal Article
In: Progress in Neurological Surgery, vol. 28, pp. 94–111, 2014.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Lee2014,
title = {Magnetoencephalography in the diagnosis of concussion},
author = {Lee, R R and Huang, M},
year = {2014},
date = {2014-01-01},
journal = {Progress in Neurological Surgery},
volume = {28},
pages = {94--111},
address = {Department of Radiology, VA San Diego Healthcare System, and University of California, San Diego, San Diego, Calif., USA.},
abstract = {Magnetoencephalography (MEG) is a biomedical technique which measures the magnetic fields emitted by the brain, generated by neuronal activity. Commercial whole-head MEG units have been available for about 15 years, but currently there are only about 20 such units operating in the USA. Here, we review the basic concepts of MEG and list some of the usual clinical indications: noninvasive localization of epileptic spikes and presurgical mapping of eloquent cortex. We then discuss using MEG to diagnose mild traumatic brain injury (mTBI; concussions). Injured brain tissues in TBI patients generate abnormal low-frequency magnetic activity (delta-waves: 1-4 Hz) that can be measured and localized by MEG. These abnormal delta-waves originate from neurons that experience deafferentation from axonal injury to the associated white matter fiber tracts, also manifested on diffusion tensor imaging as reduced fractional anisotropy. Magnetoencephalographic evaluation of abnormal delta-waves (1-4 Hz) is probably the most sensitive objective test to diagnose concussions. An automated MEG low-frequency (slow wave) source imaging method, frequency-domain vector-based spatiotemporal analysis using a L1-minimum norm (VESTAL), achieved a positive finding rate of 87% for diagnosing concussions (blast-induced plus nonblast), 100% for moderate TBI, and no false-positive diagnoses in normal controls. There were also significant correlations between the number of cortical regions generating abnormal slow waves and the total postconcussive symptom scores in TBI patients. 2014 S. Karger AG, Basel.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Acocello, S; Broshek, D K; Saliba, S
Inter-rater and intra-rater reliability of cerebral blood flow measures obtained using the Brain Acoustic Monitor Journal Article
In: Journal of Neuroscience Methods, vol. 221, pp. 85–91, 2014.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Acocello2014,
title = {Inter-rater and intra-rater reliability of cerebral blood flow measures obtained using the Brain Acoustic Monitor},
author = {Acocello, S and Broshek, D K and Saliba, S},
year = {2014},
date = {2014-01-01},
journal = {Journal of Neuroscience Methods},
volume = {221},
pages = {85--91},
address = {University of Virginia, Exercise and Sport Injury Laboratory, 210 Emmet Street South, PO Box 400407, Charlottesville, VA 22901, USA. Electronic address: ss9qb@virginia.edu.},
abstract = {BACKGROUND: Current assessment of sport-related concussion involves a multifaceted approach including neurocognitive testing, symptom report, and balance assessment. Lacking from this paradigm is a truly objective measure of the physiological changes associated with concussion. NEW METHOD: A device called the Brain Acoustic Monitor (BAM) has been developed to detect cerebral blood flow changes resulting from traumatic brain injury by amplification and comparison of sound waves created by cerebral arteries and a reference artery. The reliability of its measures is unknown, limiting its use in day-to-day assessment of concussion. Therefore, the purpose of this study was to determine the inter- and intra-rater reliability associated with BAM measures. Twenty healthy participants were assessed on two occasions, separated by at least 24h. Ten subjects were measured during the initial session by two assessors for inter-rater comparisons. Measures of positive-to-negative signal deflection (ratio) and frequency divergence from a reference arterial signal (divergence) were calculated and analyzed using Intra-class correlations (2,1). RESULTS: Inter-rater reliability ranged from poor to excellent, showing greater reliability in right brain vs. left brain measures. Intra-rater reliability was similar with a range of poor to good. COMPARISON WITH EXISTING METHODS: These findings are comparable to the reliability of current methods of concussion assessment, specifically neurocognitive testing. CONCLUSION: All BAM values obtained in our healthy subjects were well below scores that would reflect potential head injury. These findings emphasize the potential usefulness of this device in future research concerning serial measurement of cerebral perfusion pressure changes associated with sport concussion.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Johnson, B; Zhang, K; Gay, M; Neuberger, T; Horovitz, S; Hallett, M; Sebastianelli, W; Slobounov, S
Metabolic alterations in corpus callosum may compromise brain functional connectivity in MTBI patients: An H-1-MRS study Journal Article
In: Neuroscience Letters, vol. 509, pp. 5–8, 2012, ISSN: 0304-3940.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Johnson2012b,
title = {Metabolic alterations in corpus callosum may compromise brain functional connectivity in MTBI patients: An H-1-MRS study},
author = {Johnson, B and Zhang, K and Gay, M and Neuberger, T and Horovitz, S and Hallett, M and Sebastianelli, W and Slobounov, S},
doi = {10.1016/j.neulet.2011.11.013},
issn = {0304-3940},
year = {2012},
date = {2012-01-01},
journal = {Neuroscience Letters},
volume = {509},
pages = {5--8},
abstract = {After clinical resolution of signs and symptoms of mild traumatic brain injury (MTBI) it is still not clear if there are residual abnormalities of structural or functional brain networks. We have previously documented disrupted interhemispheric functional connectivity in 'asymptomatic' concussed individuals during the sub-acute phase of injury. Testing of 15 normal volunteers (NV) and 15 subacute MTBI subjects was performed within 24 h of clinical symptoms resolution and medical clearance for the first stage of aerobic activity. In this MRS study we report: (a) both in the genu and splenium of the corpus callosum NAA/Cho and NAA/Cr ratios were significantly (p \< 0.05) lower in MTBI subjects shortly after the injury compared to NVs, and (b) the metabolic ratio NAA/Cho in the splenium significantly correlated with the magnitude of inter-hippocampal functional connectivity in normal volunteers, but not in MTBI. This novel finding supports our hypothesis that the functional disruption of interhemispheric brain networks in MTBI subjects results from compromised metabolic integrity of the corpus callosum and that this persists despite apparent clinical return to baseline.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Lin, A P; Liao, H J; Merugumala, S K; Prabhu, S P; Meehan, W P; Ross, B D
Metabolic imaging of mild traumatic brain injury Journal Article
In: Brain Imaging and Behavior, vol. 6, pp. 208–223, 2012.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Lin2012,
title = {Metabolic imaging of mild traumatic brain injury},
author = {Lin, A P and Liao, H J and Merugumala, S K and Prabhu, S P and Meehan, W P and Ross, B D},
doi = {10.1007/s11682-012-9181-4},
year = {2012},
date = {2012-01-01},
journal = {Brain Imaging and Behavior},
volume = {6},
pages = {208--223},
abstract = {Traumatic brain injury results in a metabolic cascade of changes that occur at the molecular level, invisible to conventional imaging methods such as computed tomography or magnetic resonance imaging. Non-invasive metabolic imaging tools such as single photon emission computed tomography (SPECT), positron emission tomography (PET), and magnetic resonance spectroscopy (MRS) are the ideal methods for providing insight to these changes by measuring regional cerebral blood flow, glucose metabolism, and brain metabolite concentrations, respectively, after mild traumatic brain injury (mTBI). The purpose of this review is to provide an overview of the different methodologies and provide an up-to-date summary of recent findings with SPECT, PET, and MRS technologies, specifically after mTBI, as defined by standardized criteria. Given that the different physiological and pathological responses are heterogeneous, efforts will be made to separate studies at different time points after injury (acute, subacute, and chronic stages) as well as to the different types of mTBI such sports-related head injury where repetitive head injuries are much more common and may present a unique signature.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Tang, L; Ge, Y L; Sodickson, D K; Miles, L; Zhou, Y X; Reaume, J; Grossman, R I
Thalamic resting-state functional networks: Disruption in patients with mild traumatic brain injury Journal Article
In: Radiology, vol. 260, pp. 831–840, 2011, ISSN: 0033-8419.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Tang2011,
title = {Thalamic resting-state functional networks: Disruption in patients with mild traumatic brain injury},
author = {Tang, L and Ge, Y L and Sodickson, D K and Miles, L and Zhou, Y X and Reaume, J and Grossman, R I},
doi = {10.1148/radiol.11110014},
issn = {0033-8419},
year = {2011},
date = {2011-01-01},
journal = {Radiology},
volume = {260},
pages = {831--840},
abstract = {Purpose: To explore the neural correlates of the thalamus by using resting-state functional magnetic resonance (MR) imaging and to investigate whether thalamic resting-state networks (RSNs) are disrupted in patients with mild traumatic brain injury (MTBI). Materials and Methods: This HIPAA-compliant study was approved by the institutional review board, and written informed consent was obtained from 24 patients with MTBI and 17 healthy control subjects. The patients had varying degrees of symptoms, with a mean disease duration of 22 days. The resting-state functional MR imaging data were analyzed by using a standard seed-based whole-brain correlation method to characterize thalamic RSNs. Student t tests were used to perform comparisons. The association between thalamic RSNs and performance on neuropsychologic and neurobehavioral measures was also investigated in patients with MTBI by using Spearman rank correlation. Results: A normal pattern of thalamic RSNs was demonstrated in healthy subjects. This pattern was characterized as representing relatively symmetric and restrictive functional thalamocortical connectivity, suggesting an inhibitory property of the thalamic neurons during the resting state. This pattern was disrupted, with significantly increased thalamic RSNs (P \<= .005) and decreased symmetry (P = .03) in patients with MTBI compared with healthy control subjects. Increased functional thalamocortical redistributive connectivity was correlated with diminished neurocognitive functions and clinical symptoms in patients with MTBI. Conclusion: These findings of abnormal thalamic RSNs lend further support to the presumed subtle thalamic injury in patients with MTBI. Resting-state functional MR imaging can be used as an additional imaging modality for detection of thalamocortical connectivity abnormalities and for better understanding of the complex persistent postconcussive syndrome. (C) RSNA, 2011},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Unden, Johan; Romner, Bertil
Can low serum levels of S100B predict normal CT findings after minor head injury in adults?: an evidence-based review and meta-analysis Journal Article
In: Journal of Head Trauma Rehabilitation, vol. 25, pp. 228–240, 2010.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Unden2010,
title = {Can low serum levels of S100B predict normal CT findings after minor head injury in adults?: an evidence-based review and meta-analysis},
author = {Unden, Johan and Romner, Bertil},
year = {2010},
date = {2010-01-01},
journal = {Journal of Head Trauma Rehabilitation},
volume = {25},
pages = {228--240},
address = {Department of Anaesthesia and Intensive Care, Halmstad Regional Hospital, Halmstad, Sweden. johan.unden@Ithalland.se},
abstract = {OBJECTIVE: To determine whether low levels of S100B in serum can predict normal computed tomography (CT) findings after minor head injury (MHI) in adults. PARTICIPANTS: Not applicable. DESIGN: Systematic evidence-based review of the peer-reviewed literature with meta-analytical interpretation. PRIMARY MEASURES: Not applicable. RESULTS: We identified 12 eligible articles that specifically studied adult MHI patients with S100B and cranial CT scans in the acute phase after injury, comprising a total of 2466 separate patients. Individual negative predictive values of 90% to 100% were found for the ability of a negative (under cutoff) S100B level to predict a normal CT scan. A total of 6 patients included in the studies had low S100B levels and positive CT scans (0.26%) and only 1 of these patients (0.04%) had a clinically relevant CT finding. The pooled negative predictive value for all studies was more than 99% (95% CI 98%-100%), with an average prevalence for any CT finding at 8%. The studies are consistently classed as level 2 and level 3 grades of evidence, suggesting a grade B recommendation. CONCLUSION: Low serum S100B levels accurately predict normal CT findings after MHI in adults. S100B sampling should be considered in MHI patients with no focal neurological deficit, an absence of significant extracerebral injury, should be taken within 3 hours of injury, and the cutoff for omitting CT set at less than 0.10 microg/L. Care givers should also be aware of other clinical factors predictive of intracranial complications after MHI.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Wu, Trevor C; Wilde, Elisabeth A; Bigler, Erin D; Yallampalli, Ragini; McCauley, Stephen R; Troyanskaya, Maya; Chu, Zili; Li, Xiaoqi; Hanten, Gerri; Hunter, Jill V; Levin, Harvey S
Evaluating the relationship between memory functioning and cingulum bundles in acute mild traumatic brain injury using diffusion tensor imaging Journal Article
In: Journal of Neurotrauma, vol. 27, pp. 303–307, 2010.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Wu2010,
title = {Evaluating the relationship between memory functioning and cingulum bundles in acute mild traumatic brain injury using diffusion tensor imaging},
author = {Wu, Trevor C and Wilde, Elisabeth A and Bigler, Erin D and Yallampalli, Ragini and McCauley, Stephen R and Troyanskaya, Maya and Chu, Zili and Li, Xiaoqi and Hanten, Gerri and Hunter, Jill V and Levin, Harvey S},
year = {2010},
date = {2010-01-01},
journal = {Journal of Neurotrauma},
volume = {27},
pages = {303--307},
address = {Department of Psychology, Brigham Young University, Provo, Utah, USA.},
abstract = {Compromised memory functioning is one of the commonly reported cognitive sequelae seen following mild traumatic brain injury (mTBI). Diffusion tensor imaging (DTI) has been shown to be sufficiently sensitive at detecting early microstructural pathological alterations after mTBI. Given its location and shape, the cingulate, which is comprised of the cingulate gyrus (gray matter) and cingulum bundles (white matter), is selectively vulnerable to mTBI. In this study we examined the integrity of cingulum bundles using DTI, and the relationship between cingulum bundles and memory functioning. Twelve adolescents with mTBI and 11 demographically-matched healthy controls were studied. All participants with mTBI had a Glasgow Coma Scale score of 15, and were without intracranial findings on CT scan. Brain scans were performed on average 2.92 days post-injury, and all participants were administered the Verbal Selective Reminding Test (VSRT), an episodic verbal learning and memory task. Participants with mTBI had a significantly lower apparent diffusion coefficient (ADC) bilaterally than controls (p \< 0.001). Despite the marginal significance of the group difference in fractional anisotropy (FA), the effect size between groups was moderate (d = 0.66). Cognitively, healthy controls performed better than the TBI group on immediate and delayed recall; however, the difference did not reach statistical significance. In the mTBI group, FA of the left cingulum bundle was significantly correlated with 30-min delayed recall (r = -0.56},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Stulemeijer, M; Vos, P E; van der Werf, S; van Dijk, G; Rijpkema, M; Fernandez, G
How mild traumatic brain injury may affect declarative memory performance in the post-acute stage Journal Article
In: Journal of Neurotrauma, vol. 27, pp. 1585–1595, 2010, ISSN: 0897-7151.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Stulemeijer2010,
title = {How mild traumatic brain injury may affect declarative memory performance in the post-acute stage},
author = {Stulemeijer, M and Vos, P E and van der Werf, S and van Dijk, G and Rijpkema, M and Fernandez, G},
doi = {10.1089/neu.2010.1298},
issn = {0897-7151},
year = {2010},
date = {2010-01-01},
journal = {Journal of Neurotrauma},
volume = {27},
pages = {1585--1595},
abstract = {Memory deficits are among the most frequently reported sequelae of mild traumatic brain injury (MTBI), especially early after injury. To date, these cognitive deficits remain poorly understood, as in most patients the brain is macroscopically intact. To identify the mechanism by which MTBI causes declarative memory impairments, we probed the functionality of the medial temporal lobe (MTL) and the prefrontal cortex (PFC), within 6 weeks after injury in 43 patients from a consecutive cohort, and matched healthy controls. In addition to neuropsychological measures of declarative memory and other cognitive domains, all subjects underwent functional magnetic resonance imaging (fMRI). Behavioral results showed poorer declarative memory performance in patients than controls, and decreasing performance with increasing duration of post-traumatic amnesia (a measure of injury severity). Task performance in the scanner was, as intended by the task and design, similar in patients and controls, and did not relate to injury severity. The task used reliably activated the MTL and PFC. Although we did not find significant differences in brain activity when comparing patients and controls, we revealed, in agreement with our neuropsychological findings, an inverse correlation between MTL activity and injury severity. In contrast, no difference in prefrontal activation was found between patients and controls, nor was there a relation with injury severity. On a behavioral level, injury severity was inversely related to declarative memory performance. In all, these findings suggest that reduced medial temporal functionality may contribute to poorer declarative memory performance in the post-acute stage of MTBI, especially in patients with longer post-traumatic amnesia.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Govind, Varan; Gold, Stuart; Kaliannan, Krithica; Saigal, Gaurav; Falcone, Steven; Arheart, Kristopher L; Harris, Leo; Jagid, Jonathan; Maudsley, Andrew A
Whole-brain proton MR spectroscopic imaging of mild-to-moderate traumatic brain injury and correlation with neuropsychological deficits Journal Article
In: Journal of Neurotrauma, vol. 27, pp. 483–496, 2010.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Govind2010,
title = {Whole-brain proton MR spectroscopic imaging of mild-to-moderate traumatic brain injury and correlation with neuropsychological deficits},
author = {Govind, Varan and Gold, Stuart and Kaliannan, Krithica and Saigal, Gaurav and Falcone, Steven and Arheart, Kristopher L and Harris, Leo and Jagid, Jonathan and Maudsley, Andrew A},
year = {2010},
date = {2010-01-01},
journal = {Journal of Neurotrauma},
volume = {27},
pages = {483--496},
address = {Department of Radiology, University of Miami School of Medicine, Miami, Florida 33136, USA. VGovind@med.miami.edu},
abstract = {Changes in the distribution of the magnetic resonance (MR)-observable brain metabolites N-acetyl aspartate (NAA), total choline (Cho), and total creatine (Cre), following mild-to-moderate closed-head traumatic brain injury (mTBI) were evaluated using volumetric proton MR spectroscopic imaging (MRSI). Studies were carried out during the subacute time period following injury, and associations of metabolite indices with neuropsychological test (NPT) results were evaluated. Twenty-nine subjects with mTBI and Glasgow Coma Scale (GCS) scores of 10-15 were included. Differences in individual metabolite and metabolite ratio distributions relative to those of age-matched control subjects were evaluated, as well as analyses by hemispheric lobes and tissue types. Primary findings included a widespread decrease of NAA and NAA/Cre, and increases of Cho and Cho/NAA, within all lobes of the TBI subject group, and with the largest differences seen in white matter. Examination of the association between all of the metabolite measures and the NPT scores found the strongest negative correlations to occur in the frontal lobe and for Cho/NAA. No significant correlations were found between any of the MRSI or NPT measures and the GCS. These results demonstrate that significant and widespread alterations of brain metabolites occur as a result of mild-to-moderate TBI, and that these measures correlate with measures of cognitive performance.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Gasparovic, Charles; Yeo, Ronald; Mannell, Maggie; Ling, Josef; Elgie, Robert; Phillips, John; Doezema, David; Mayer, Andrew R
Neurometabolite concentrations in gray and white matter in mild traumatic brain injury: an 1H-magnetic resonance spectroscopy study Journal Article
In: Journal of Neurotrauma, vol. 26, pp. 1635–1643, 2009.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Gasparovic2009,
title = {Neurometabolite concentrations in gray and white matter in mild traumatic brain injury: an 1H-magnetic resonance spectroscopy study},
author = {Gasparovic, Charles and Yeo, Ronald and Mannell, Maggie and Ling, Josef and Elgie, Robert and Phillips, John and Doezema, David and Mayer, Andrew R},
year = {2009},
date = {2009-01-01},
journal = {Journal of Neurotrauma},
volume = {26},
pages = {1635--1643},
address = {The Mind Research Network, Albuquerque, New Mexico 7131, USA. chuck@unm.edu},
abstract = {Single-voxel proton magnetic resonance imaging ((1)H-MRS) and proton MR spectroscopic imaging ((1)H-MRSI) were used to compare brain metabolite levels in semi-acute mild traumatic brain injury (mTBI) patients (n = 10) and matched healthy controls (n = 9). The (1)H-MRS voxel was positioned in the splenium, a region known to be susceptible to axonal injury in TBI, and a single (1)H-MRSI slice was positioned above the lateral ventricles. To increase sensitivity to the glutamate (Glu) and the combined glutamate-glutamine (Glx) signal, an inter-pulse echo time shown to emphasize the major Glu signals was used along with an analysis method that reduces partial volume errors by using water as a concentration standard. Our preliminary findings indicate significantly lower levels of gray matter Glx and higher levels of white matter creatine-phosphocreatine (Cr) in mTBI subjects relative to healthy controls. Furthermore, Cr levels were predictive of executive function and emotional distress in the combined groups. These results suggest that perturbations in Cr, a critical component of the brain's energy metabolism, and Glu, the brain's major neurotransmitter, may occur following mTBI. Moreover, the different pattern of results for gray and white matter suggests tissue-specific metabolic responses to mTBI.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Ruan, Shuolun; Noyes, Katia; Bazarian, Jeffrey J
The economic impact of S-100B as a pre-head CT screening test on emergency department management of adult patients with mild traumatic brain injury Journal Article
In: Journal of Neurotrauma, vol. 26, pp. 1655–1664, 2009.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Ruan2009,
title = {The economic impact of S-100B as a pre-head CT screening test on emergency department management of adult patients with mild traumatic brain injury},
author = {Ruan, Shuolun and Noyes, Katia and Bazarian, Jeffrey J},
year = {2009},
date = {2009-01-01},
journal = {Journal of Neurotrauma},
volume = {26},
pages = {1655--1664},
address = {Department of Community and Preventive Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA. shuolun.ruan@aya.yale.edu},
abstract = {Recent research suggests that serum S-100B may serve as a good pre-head computed tomography (CT) screening test because of its high sensitivity for abnormal head CT scans. The potential economic impact of using S-100B in the emergency department setting for management of adult patients with isolated mild traumatic brain injury (mTBI) has not been evaluated despite its clinical implementation in Europe. Using evidence from the literature, we constructed a decision tree to compare the average cost per patient of using S-100B as a pre-head CT screening test to the current practice of ordering CT scans based on patients' presenting symptoms without the aid of S-100B. When compared to scanning 45-77% of isolated mTBI patients based upon their presenting symptoms, using S-100B as a pre-head CT screen does not lower hospital costs ($281 versus $160), primarily due to its low specificity for abnormal head CT scans. Sensitivity analyses showed, however, that S-100B becomes cost-lowering when the proportion of mTBI patients being scanned exceeds 78%, or when final CT scan results require 96 min or more than the wait for blood test results. Generally speaking, if blood test results require less time than imaging, and if head CT scan rates for patients with isolated mTBI are relatively high, using S-100B will lower costs. Recommendations for using S-100B as a screening tool should account for setting-specific characteristics and their consequent economic impacts. Despite its high sensitivity and excellent negative predictive value, serum S-100B has low specificity and low positive predictive value, limiting its ability to reduce numbers of CT scans and hospital costs.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Chen, Jen Kai; Johnston, Karen M; Petrides, Michael; Ptito, Alain
Recovery from mild head injury in sports: evidence from serial functional magnetic resonance imaging studies in male athletes Journal Article
In: Clinical Journal of Sport Medicine, vol. 18, pp. 241–247, 2008.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Chen2008a,
title = {Recovery from mild head injury in sports: evidence from serial functional magnetic resonance imaging studies in male athletes},
author = {Chen, Jen Kai and Johnston, Karen M and Petrides, Michael and Ptito, Alain},
year = {2008},
date = {2008-01-01},
journal = {Clinical Journal of Sport Medicine},
volume = {18},
pages = {241--247},
address = {Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.},
abstract = {OBJECTIVE: To examine functional brain activation patterns before and after postconcussive symptoms (PCS) resolution. DESIGN: Prospective serial study with male athletes using functional magnetic resonance imaging (fMRI). SETTING: Hospital laboratory and imaging facility. PARTICIPANTS: 9 symptomatic concussed athletes who experienced persisting PCS at least 1 month postinjury and 6 healthy athletes. INTERVENTIONS: All athletes filled out a PCS checklist and underwent an fMRI session during which they performed a working-memory task. MAIN OUTCOME MEASUREMENTS: Behavioral outcomes were response speed and accuracy on the working memory tasks performed during the fMRI session. Functional imaging outcomes were blood oxygen level-dependent fMRI activation patterns associated with a working memory task. RESULTS:: There was no difference in behavioral performance between the groups. Despite normal structural MRI findings, all symptomatic concussed athletes initially showed atypical brain activation patterns in the dorsolateral prefrontal cortex (DLPC). Compared to the initial postinjury evaluation, those athletes at follow-up with PCS resolved showed significant increases in activation in the left DLPC. Concussed athletes whose PCS status remained unchanged at follow-up continued to show atypical activation in DLPC. Healthy athletes showed remarkably clear and consistent brain activations in DLPC initially as well as in follow-up, highlighting the test-retest reliability of fMRI. CONCLUSIONS: The results demonstrate the feasibility of using fMRI to detect an underlying pathology in symptomatic concussed athletes with normal structural imaging results and its potential to document recovery. Such information may be of considerable value for clinical judgment and patient management.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Ptito, Alain; Chen, Jen-Kai; Johnston, Karen M
Contributions of functional magnetic resonance imaging (fMRI) to sport concussion evaluation Journal Article
In: NeuroRehabilitation, vol. 22, pp. 217–227, 2007.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Ptito2007,
title = {Contributions of functional magnetic resonance imaging (fMRI) to sport concussion evaluation},
author = {Ptito, Alain and Chen, Jen-Kai and Johnston, Karen M},
year = {2007},
date = {2007-01-01},
journal = {NeuroRehabilitation},
volume = {22},
pages = {217--227},
address = {Montreal Neurological Institute McGill University, Montreal, Quebec, Canada. alain.ptito@mcgill.ca},
abstract = {Mild traumatic brain injury (mTBI) in contact sport is a problem of such magnitude that improved approaches to diagnosis, investigation and management are urgent. Concussion has traditionally been described as a transient, fully reversible, cerebral dysfunction. However, this seemingly 'mild' injury sometimes results in long-lasting and disabling post-concussion symptoms (PCS) and abnormal neuropsychological profiles characteristic of frontal and/or temporal lobe dysfunction. At present, the pathological changes following concussion remain unclear, but it is now widely accepted that concussion results mainly in functional disturbance rather than structural damage. Therefore, functional imaging techniques can help in demonstrating brain abnormalities undetectable by structural imaging methods. This paper will review the use of functional magnetic resonance imaging (fMRI) in studies of concussion. Our existing and ongoing fMRI studies will be described as examples to highlight the potential and contribution of this non-invasive functional neuroimaging technique in the assessment of sports-related concussion and its management. [References: 54]},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Kirov, Ivan; Fleysher, Lazar; Babb, James S; Silver, Jonathan M; Grossman, Robert I; Gonen, Oded
Characterizing 'mild' in traumatic brain injury with proton MR spectroscopy in the thalamus: Initial findings Journal Article
In: Brain Injury, vol. 21, pp. 1147–1154, 2007.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Kirov2007,
title = {Characterizing 'mild' in traumatic brain injury with proton MR spectroscopy in the thalamus: Initial findings},
author = {Kirov, Ivan and Fleysher, Lazar and Babb, James S and Silver, Jonathan M and Grossman, Robert I and Gonen, Oded},
year = {2007},
date = {2007-01-01},
journal = {Brain Injury},
volume = {21},
pages = {1147--1154},
address = {Department of Radiology, New York, USA.},
abstract = {OBJECTIVE: Although most mild traumatic brain injury (mTBI) patients suffer any of several post-concussion symptoms suggestive of thalamic involvement, they rarely present with any MRI-visible pathology. The aim here, therefore, is to characterize their thalamic metabolite levels with proton MR spectroscopy (1H-MRS) compared with healthy controls. METHODS: T1-weighted MRI and multi-voxel 1H-MRS were acquired at 3 Tesla from 20 mTBI (Glasgow Coma Scale score of 15-13) patients, 19-59 years old, 0-7 years post-injury; and from 17 age and gender matched healthy controls. Mixed model regression was used to compare patients and controls with respect to the mean absolute N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) levels within each thalamus. RESULTS: The mTBI-induced thalamic metabolite concentration changes were under +/- 13.0% for NAA, +/- 13.5% for Cr and +/- 18.8% for Cho relative to their corresponding concentrations in the controls: NAA: 10.08 +/- 0.30 (mean +/- standard error), Cr: 5.62 +/- 0.18 and Cho: 2.08 +/- 0.09 mM. These limits represent the minimal detectable differences between the two cohorts. CONCLUSION: The change in metabolic levels in the thalamus of patients who sustained clinically defined mTBI could be an instrumental characteristic of 'mildness'. 1H-MRS could, therefore, serve as an objective laboratory indicator for differentiating 'mild' from more severe categories of head-trauma, regardless of the presence or lack of current clinical symptoms.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Kraus, Marilyn F; Susmaras, Teresa; Caughlin, Benjamin P; Walker, Corey J; Sweeney, John A; Little, Deborah M
White matter integrity and cognition in chronic traumatic brain injury: a diffusion tensor imaging study Journal Article
In: Brain, vol. 130, pp. 2508–2519, 2007.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Kraus2007,
title = {White matter integrity and cognition in chronic traumatic brain injury: a diffusion tensor imaging study},
author = {Kraus, Marilyn F and Susmaras, Teresa and Caughlin, Benjamin P and Walker, Corey J and Sweeney, John A and Little, Deborah M},
year = {2007},
date = {2007-01-01},
journal = {Brain},
volume = {130},
pages = {2508--2519},
address = {Department of Psychiatry, University of Illinois at Chicago Medical Center, Chicago, IL, USA. mkraus@psych.uic.edu},
abstract = {Traumatic brain injury (TBI) is a serious public health problem. Even injuries classified as mild, the most common, can result in persistent neurobehavioural impairment. Diffuse axonal injury is a common finding after TBI, and is presumed to contribute to outcomes, but may not always be apparent using standard neuroimaging. Diffusion tensor imaging (DTI) is a more recent method of assessing axonal integrity in vivo. The primary objective of the current investigation was to characterize white matter integrity utilizing DTI across the spectrum of chronic TBI of all severities. A secondary objective was to examine the relationship between white matter integrity and cognition. Twenty mild, 17 moderate to severe TBI and 18 controls underwent DTI and neuropsychological testing. Fractional anisotropy, axial diffusivity and radial diffusivity were calculated from the DTI data. Fractional anisotropy was the primary measure of white matter integrity. Region of interest analysis included anterior and posterior corona radiata, cortico-spinal tracts, cingulum fibre bundles, external capsule, forceps minor and major, genu, body and splenium of the corpus callosum, inferior fronto-occipital fasciculus, superior longitudinal fasciculus and sagittal stratum. Cognitive domain scores were calculated from executive, attention and memory testing. Decreased fractional anisotropy was found in all 13 regions of interest for the moderate to severe TBI group, but only in the cortico-spinal tract, sagittal stratum and superior longitudinal fasciculus for the mild TBI group. White Matter Load (a measure of the total number of regions with reduced FA) was negatively correlated with all cognitive domains. Analysis of radial and axial diffusivity values suggested that all severities of TBI can result in a degree of axonal damage, while irreversible myelin damage was only apparent for moderate to severe TBI. The present data emphasize that white matter changes exist on a spectrum, including mild TBI. An index of global white matter neuropathology (White Matter Load) was related to cognitive function, such that greater white matter pathology predicted greater cognitive deficits. Mechanistically, mild TBI white matter changes may be primarily due to axonal damage as opposed to myelin damage. The more severe injuries impact both. DTI provides an objective means for determining the relationship of cognitive deficits to TBI, even in cases where the injury was sustained years prior to the evaluation.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Bazarian, Jeffrey J; Blyth, Brian; Cimpello, Lynn
Bench to bedside: evidence for brain injury after concussion--looking beyond the computed tomography scan Journal Article
In: Academic Emergency Medicine, vol. 13, pp. 199–214, 2006.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Bazarian2006a,
title = {Bench to bedside: evidence for brain injury after concussion--looking beyond the computed tomography scan},
author = {Bazarian, Jeffrey J and Blyth, Brian and Cimpello, Lynn},
year = {2006},
date = {2006-01-01},
journal = {Academic Emergency Medicine},
volume = {13},
pages = {199--214},
address = {Department of Emergency Medicine, Strong Memorial Hospital, University of Rochester, Rochester, NY 14642, USA. jeff_bazarian@urmc.rochester.edu},
abstract = {The emergency management of cerebral concussion typically centers on the decision to perform a head computed tomography (CT) scan, which only rarely detects hemorrhagic lesions requiring neurosurgery. The absence of hemorrhage on CT scan often is equated with a lack of brain injury. However, observational studies revealing poor long-term cognitive outcome after concussion suggest that brain injury may be present despite a normal CT scan. To explore this idea further, the authors reviewed the evidence for objective neurologic injury in humans after concussion, with particular emphasis on those with a normal brain CT. This evidence comes from studies involving brain tissue pathology, CT scanning, magnetic resonance image (MRI) scanning, serum biomarkers, formal cognitive and balance tests, functional MRI, positron emission tomography, and single-photon emission computed tomography scanning. Each section is accompanied by technical information to help the reader understand what these tests are, not to endorse their use clinically. The authors discuss the strengths and weaknesses of the evidence in each case. These reports make a compelling case for the existence of concussion as a clinically relevant disease with demonstrable neurologic pathology. Areas for future emergency medicine research are suggested. [References: 169]},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Chappell, M H; Ulug, A M; Zhang, L; Heitger, M H; Jordan, B D; Zimmerman, R D; Watts, R
Distribution of microstructural damage in the brains of professional boxers: A diffusion MRI study Journal Article
In: Journal of Magnetic Resonance Imaging, vol. 24, pp. 537–542, 2006, ISSN: 1053-1807.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Chappell2006,
title = {Distribution of microstructural damage in the brains of professional boxers: A diffusion MRI study},
author = {Chappell, M H and Ulug, A M and Zhang, L and Heitger, M H and Jordan, B D and Zimmerman, R D and Watts, R},
doi = {10.1002/jmri.20656},
issn = {1053-1807},
year = {2006},
date = {2006-01-01},
journal = {Journal of Magnetic Resonance Imaging},
volume = {24},
pages = {537--542},
abstract = {Purpose: To investigate and localize cerebral abnormalities in professional boxers with no history of moderate or severe head trauma. Materials and Methods: Diffusion tensor imaging (DTI) was used to determine the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in the brains of 81 professional male boxers and 12 male control subjects. Voxel-based analysis (VBA) of both the diffusion and anisotropy values was performed using statistical parametric mapping (SPM). From this objective analysis, regions of microstructural abnormalities in the brains of the boxers were located. Results: Increases in the ADC, and decreases in FA were identified in deep white matter (WM), while decreases in ADC were identified in cortical gray matter (GM). Regions of positive correlation between ADC and age were also found in both the boxer and control groups, although the regions and strength of the correlation were not the same in each group. Conclusion: Using VBA, we localized previously unreported abnormalities in the brains of professional boxers. These abnormalities are assumed to reflect cumulative (chronic) brain injury resulting from nonsevere head trauma.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Cimatti, M
Assessment of metabolic cerebral damage using proton magnetic resonance spectroscopy in mild traumatic brain injury Journal Article
In: Journal of Neurosurgical Sciences, vol. 50, pp. 83–88, 2006.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Cimatti2006,
title = {Assessment of metabolic cerebral damage using proton magnetic resonance spectroscopy in mild traumatic brain injury},
author = {Cimatti, M},
year = {2006},
date = {2006-01-01},
journal = {Journal of Neurosurgical Sciences},
volume = {50},
pages = {83--88},
address = {Department of Neurological Sciences and Neurosurgery, University La Sapienza, Rome, Italy.},
abstract = {AIM: We want to appraise, through proton magnetic resonance spectroscopy (H1-MRI), the NAA's values and it's changing in cerebral tissue in consequence of cranial trauma. METHODS: Six patients with TBI undergo to H1-MRI to asses the changes occurring briefly after trauma in the spectrum's composition. RESULTS: As far as the first two cases we founded a lowering of the NAA's values. In the other four cases the NAA values were normal in all but one, which slightly brought the values of the NAA/Cr and NAA/Cho lower in comparison to the standard values. CONCLUSIONS: Existing a correlation between NAA and ATP it can be drawn that the reduction of NAA is correlated to energetic type damage. Despite the smallness of data, it remains really important that we should have a tool to monitor the cerebral metabolic picture after a mild trauma.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Chen, J K; Johnston, K M; Frey, S; Petrides, M; Worsley, K; Ptito, A
Functional abnormalities in symptomatic concussed athletes: an fMRI study Journal Article
In: Neuroimage, vol. 22, pp. 68–82, 2004.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Chen2004,
title = {Functional abnormalities in symptomatic concussed athletes: an fMRI study},
author = {Chen, J K and Johnston, K M and Frey, S and Petrides, M and Worsley, K and Ptito, A},
year = {2004},
date = {2004-01-01},
journal = {Neuroimage},
volume = {22},
pages = {68--82},
address = {Neuropsychology Department/Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.},
abstract = {Our aim was to quantify with functional magnetic resonance imaging (fMRI) changes in brain activity in concussed athletes and compare the results with those of normal control subjects. Regional brain activations associated with a working memory task were obtained from a group of concussed athletes (15 symptomatic, 1 asymptomatic) and eight matched control subjects, using blood oxygen level dependent (BOLD) fMRI. The average percent signal change from baseline to working memory condition in each region of interest was computed. Symptomatic concussed athletes demonstrated task-related activations in some but not all the regions of interest, even when they performed as well as the control subjects. Furthermore, several concussed athletes had additional increases in activity outside the regions of interest, not seen in the control group. Quantitative analysis of BOLD signals within regions of interest revealed that, in general, concussed athletes had different BOLD responses compared to the control subjects. The task-related activation pattern of the one symptom-free athlete was comparable to that of the control group. We also repeated the study in one athlete whose symptoms had resolved. On the first study, when he was still symptomatic, less task-related activations were observed. On follow-up, once his symptoms had disappeared, the task-related activations became comparable to those of the control group. These results demonstrate the potential of fMRI, in conjunction with the working memory task, to identify an underlying pathology in symptomatic concussed individuals with normal structural imaging results.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Xiao, Xing-Yi; Xue, Guan-Sheng; Xu, Guo-Zhen; Yin, Xiao-Mei
Change and clinical significance of cerebral blood flow after concussion of brain detected with three-dimensional transcranial Doppler Journal Article
In: Chinese Journal of Traumatology, vol. 6, pp. 124–126, 2003.
BibTeX | Tags: Imaging & EEG Physiopathology
@article{Xiao2003,
title = {Change and clinical significance of cerebral blood flow after concussion of brain detected with three-dimensional transcranial Doppler},
author = {Xiao, Xing-Yi and Xue, Guan-Sheng and Xu, Guo-Zhen and Yin, Xiao-Mei},
year = {2003},
date = {2003-01-01},
journal = {Chinese Journal of Traumatology},
volume = {6},
pages = {124--126},
address = {Department of Emergency, 205th Hospital of PLA, Jinzhou 121001, China. 225205225205@sina.com},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Shaw, Nigel A
The neurophysiology of concussion Journal Article
In: Progress in Neurobiology, vol. 67, pp. 281–344, 2002, ISSN: 0301-0082.
Abstract | Links | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Shaw2002,
title = {The neurophysiology of concussion},
author = {Shaw, Nigel A},
doi = {10.1016/s0301-0082(02)00018-7},
issn = {0301-0082},
year = {2002},
date = {2002-01-01},
journal = {Progress in Neurobiology},
volume = {67},
pages = {281--344},
abstract = {Cerebral concussion is both the most common and most puzzling type of traumatic brain injury (TBI). It is normally produced by acceleration (or deceleration) of the head and is characterized by a sudden brief impairment of consciousness, paralysis of reflex activity and loss of memory. It has long been acknowledged that one of the most worthwhile techniques for studying the acute pathophysiology of concussion is by the recording of neurophysiological activity such as the electroencephalogram (EEG) and sensory evoked potentials (EPs) from experimental animals. In the first parts of this review, the majority of such studies conducted during the past half century are critically reviewed. When potential methodological flaws and limitations such as anesthetic protocols, infliction of multiple blows and delay in onset of recordings were taken into account, two general principles could be adduced. First, the immediate post-concussive EEG was excitatory or epileptiform in nature. Second, the cortical EP waveform was totally lost during this period. In the second parts of this review, five theories of concussion which have been prominent during the past century are summarized and supportive evidence assessed. These are the vascular, reticular, centripetal, pontine cholinergic and convulsive hypotheses. It is concluded that only the convulsive theory is readily compatible with the neurophysiological data and can provide a totally viable explanation for concussion. The chief tenet of the convulsive theory is that since the symptoms of concussion bear a strong resemblance to those of a generalized epileptic seizure, then it is a reasonable assumption that similar pathobiological processes underlie them both. Further, it is demonstrated that EPs and EEGs recorded acutely following concussive trauma are indeed the same or similar to those obtained following the induction of a state of generalized seizure activity (GSA). According to the present incarnation of the convulsive theory, the energy imparted to the brain by the sudden mechanical loading of the head may generate turbulent rotatory and other movements of the cerebral hemispheres and so increase the chances of a tissue-deforming collision or impact between the cortex and the boney walls of the skull. In this conception, loss of consciousness is not orchestrated by disruption or interference with the function of the brainstem reticular activating system. Rather, it is due to functional deafferentation of the cortex as a consequence of diffuse mechanically-induced depolarization and synchronized discharge of cortical neurons. A convulsive theory can also explain traumatic amnesia, autonomic disturbances and the miscellaneous collection of symptoms of the post-concussion syndrome more adequately than any of its rivals. In addition, the symptoms of minor concussion (a.k.a. being stunned, dinged, or dazed) are often strikingly similar to minor epilepsy such as petit mal. The relevance of the convulsive theory to a number of associated problems is also discussed. These include the relationship between concussion and more serious types of closed head injury, the utility of animal models of severe brain trauma, the etiology of the cognitive deficits which may linger long after a concussive injury, the use of concussive (captive bolt) techniques to stun farm animals prior to slaughter and the question of why some animals (such as the woodpecker) can tolerate massive accelerative forces without being knocked out.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Hofman, P A; Stapert, S Z; van Kroonenburgh, M J; Jolles, J; de Kruijk, J; Wilmink, J T
MR imaging, single-photon emission CT, and neurocognitive performance after mild traumatic brain injury Journal Article
In: AJNR: American Journal of Neuroradiology, vol. 22, pp. 441–449, 2001.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Hofman2001,
title = {MR imaging, single-photon emission CT, and neurocognitive performance after mild traumatic brain injury},
author = {Hofman, P A and Stapert, S Z and van Kroonenburgh, M J and Jolles, J and de Kruijk, J and Wilmink, J T},
year = {2001},
date = {2001-01-01},
journal = {AJNR: American Journal of Neuroradiology},
volume = {22},
pages = {441--449},
address = {Department of Radiology, University Hospital Maastricht, The Netherlands.},
abstract = {BACKGROUND AND PURPOSE: Mild traumatic brain injury (mTBI) (Glasgow Coma Scale = 14-15) is a common neurologic disorder and a common cause of neurocognitive deficits in the young population. Most patients recover fully from mTBI, but 15% to 29% of patients have persistent neurocognitive problems. Although a partially organic origin is considered likely, little brain imaging evidence exists for this assumption. The aims of the present study were to establish the prevalence of posttraumatic lesions in mTBI patients on MR images and to assess the relation between these imaging findings and posttraumatic symptoms. Secondly, we explored the value of early posttraumatic single-photon emission CT (SPECT) for the evaluation of mTBI. METHODS: Twenty-one consecutive patients were included in the study. Patients underwent MR examination, technetium-99m hexamethylpropylene amine oxime SPECT, and neurocognitive assessment within 5 days after injury. Neurocognitive follow-up was conducted 2 and 6 months after injury, and MR imaging was repeated after 6 months. Lesion size and brain atrophy were measured on the MR studies. RESULTS: Twelve (57%) of 21 patients had abnormal MR findings, and 11 (61%) of 18 had abnormal SPECT findings. Patients with abnormal MR or SPECT findings had brain atrophy at follow-up. The mean neurocognitive performance of all subjects was within normal range. There was no difference in neurocognitive performance between patients with normal and abnormal MR findings. Patients with abnormal MR findings only showed significantly slower reaction times during a reaction-time task. Seven patients had persistent neurocognitive complaints and one patient met the criteria for a postconcussional syndrome. CONCLUSION: Brain lesions are common after mTBI; up to 77% of patients may have abnormal findings either on MR images or SPECT scans, and these lesions may lead to brain atrophy. The association between hypoperfusion seen on acute SPECT and brain atrophy after 6 months suggests the possibility of (secondary) ischemic brain damage. There is only a weak correlation between neuroimaging findings and neurocognitive outcome.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Nariai, T; Suzuki, R; Ohta, Y; Ohno, K; Hirakawa, K
Focal cerebral hyperemia in postconcussive amnesia Journal Article
In: Journal of Neurotrauma, vol. 18, pp. 1323–1332, 2001.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Nariai2001,
title = {Focal cerebral hyperemia in postconcussive amnesia},
author = {Nariai, T and Suzuki, R and Ohta, Y and Ohno, K and Hirakawa, K},
year = {2001},
date = {2001-01-01},
journal = {Journal of Neurotrauma},
volume = {18},
pages = {1323--1332},
address = {Department of Neurosurgery, Tokyo Medical and Dental University, Japan. nariai.nsrg@tmd.ac.jp},
abstract = {Transient amnesia caused by minor head injury is commonly encountered in daily neurosurgical practice, but the mechanism of such amnesia has not been extensively studied. We measured the regional cerebral blood flow (rCBF) of patients with postconcussive amnesia with Xe/CT CBF to examine whether a focal disturbance of CBF exists. The Xe/CT CBF study was performed in eight patients with closed head injury without organic cerebral lesion while they were suffering from posttraumatic amnesia (concussion group). The time interval between accident and CBF measurement was less than 2 h in three patients, 5-6 h in two, 8-9 h in two, and 18 in one. The results were compared with those of nine normal volunteers and eight other age-matched patients who recovered without any neurological deficit despite the presence of hemorrhagic regions (mild hemorrhage group). The rCBF of the concussion group was significantly elevated in the bilateral mesial temporal cortex in comparison to the normal group. The rCBF in the mild hemorrhage group was lower than that of normal controls in all regions. The analysis of right-left difference in CBF indicated that there was significant asymmetry (right \> left) in the frontal and temporal cortex in the concussion group, but not in the normal and mild hemorrhage group. This Xe/CT CBF study in acute stages of cerebral concussion, in which patients were amnestic, detected focal cerebral hyperemia. Such hyperemia in regions closely related to human memory function may be the result of vasoparalysis or the compensatory activation of memory circuits after denervation injury.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Bergsneider, M; Hovda, D A; McArthur, D L; Etchepare, M; Huang, S C; Sehati, N; Satz, P; Phelps, M E; Becker, D P
Metabolic recovery following human traumatic brain injury based on FDG-PET: time course and relationship to neurological disability Journal Article
In: Journal of Head Trauma Rehabilitation, vol. 16, pp. 135–148, 2001.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Bergsneider2001,
title = {Metabolic recovery following human traumatic brain injury based on FDG-PET: time course and relationship to neurological disability},
author = {Bergsneider, M and Hovda, D A and McArthur, D L and Etchepare, M and Huang, S C and Sehati, N and Satz, P and Phelps, M E and Becker, D P},
year = {2001},
date = {2001-01-01},
journal = {Journal of Head Trauma Rehabilitation},
volume = {16},
pages = {135--148},
address = {Department of Surgery, Division of Neurosurgery, UCLA Brain Research Institute, Harbor-University of California at Los Angeles Medical Center, USA.},
abstract = {OBJECTIVE: Utilizing [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET), we assessed the temporal pattern and the correlation of functional and metabolic recovery following human traumatic brain injury. DESIGN AND SUBJECTS: Fifty-four patients with injury severity ranging from mild to severe were studied. Thirteen of these patients underwent both an acute and delayed FDG-PET study. RESULTS: Analysis of the pooled global cerebral metabolic rate of glucose (CMRglc) values revealed that the intermediate metabolic reduction phase begins to resolve approximately one month following injury, regardless of injury severity. The correlation, in the 13 patients studied twice, between the extent of change in neurologic disability, assessed by the Disability Rating Scale (DRS), and the change in CMRglc from the early to late period was modest (r = -0.42). Potential explanations for this rather poor correlation are discussed. A review of the pertinent literature regarding the use of PET and related imaging modalities, including single photon emission tomography (SPECT) for the assessment of patients following traumatic brain injury is given. CONCLUSION: The dynamic profile of CMRglc that changes following traumatic brain injury is seemingly stereotypic across a broad range and severity of injury types. Quantitative FDG-PET cannot be used as a surrogate technique for estimating degree of global functional recovery following traumatic brain injury.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
McAllister, T W; Sparling, M B; Flashman, L A; Guerin, S J; Mamourian, A C; Saykin, A J
Differential working memory load effects after mild traumatic brain injury Journal Article
In: Neuroimage, vol. 14, pp. 1004–1012, 2001.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{McAllister2001,
title = {Differential working memory load effects after mild traumatic brain injury},
author = {McAllister, T W and Sparling, M B and Flashman, L A and Guerin, S J and Mamourian, A C and Saykin, A J},
year = {2001},
date = {2001-01-01},
journal = {Neuroimage},
volume = {14},
pages = {1004--1012},
address = {Section of Neuropsychiatry and Brain Imaging Laboratory, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA.},
abstract = {The objective of this study was to explore the effects of increasing working memory (WM) processing load on previously observed abnormalities in activation of WM circuitry shortly after mild traumatic brain injury (MTBI). Brain activation patterns in response to increasing WM processing load (auditory n-back: 0-, 1-, 2-, and 3-back conditions) were assessed with fMRI in 18 MTBI patients within 1 month of their injury and in 12 healthy controls. Performance accuracy on these tasks was also measured. Brain activation patterns differed between MTBI patients and controls in response to increasing WM processing loads. Controls maintained their ability to increase activation in regions of WM circuitry with each increase in WM processing load. MTBI patients showed disproportionately increased activation during the moderate processing load condition, but very little increase in activation associated with the highest processing load condition. Task performance did not differ significantly between groups on any task condition. MTBI patients showed a different pattern of allocation of processing resources associated with a high processing load condition compared to healthy controls, despite similar task performance. This suggests that injury-related changes in ability to activate or modulate WM processing resources might underlie some of the memory complaints after MTBI.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Mussack, T; Biberthaler, P; Wiedemann, E; Kanz, K G; Englert, A; Gippner-Steppert, C; Jochum, M
S-100b as a screening marker of the severity of minor head trauma (MHT)--a pilot study Journal Article
In: Acta Neurochirurgica - Supplement, vol. 76, pp. 393–396, 2000.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Mussack2000,
title = {S-100b as a screening marker of the severity of minor head trauma (MHT)--a pilot study},
author = {Mussack, T and Biberthaler, P and Wiedemann, E and Kanz, K G and Englert, A and Gippner-Steppert, C and Jochum, M},
year = {2000},
date = {2000-01-01},
journal = {Acta Neurochirurgica - Supplement},
volume = {76},
pages = {393--396},
address = {Chirurgische Klinik, Kliniken Innenstadt, Ludwig-Maximilians-Universitat, Munchen, Germany.},
abstract = {Due to its neural tissue specificity S-100b is considered as a screening marker of cerebral injury in head trauma patients. However, the occurrence and relevance of an increased S-100b serum level in minor head trauma (MHT) is still debated. Therefore, the purpose of our study was to evaluate the diagnostic utility of S-100b measurements in a level I trauma center emergency room (ER). Eighty patients presenting with clinical symptoms of MHT (GCS score of 13-15, transitory loss of consciousness, amnesia, nausea) were prospectively recruited. Blood samples were drawn at 0 h, 6 h and 24 h after admission, and a cerebral computed tomography (CT) was performed. The reference group consisted of 10 patients with severe head injury (GCS score \< 8), the control group of 20 healthy volunteers. Concentrations of S-100b in serum were determined by an immunoluminometric assay. The results were compared with the plasma levels of polymorphonuclear (PMN) elastase as an established general trauma marker. In the MHT group, the S-100b serum level revealed 1.26 +/- 0.57 ng/ml at study entry (73.46 +/- 47.53 min after trauma). In comparison, the S-100b concentration was significantly elevated in patients with severe head trauma (5.26 +/- 1.65 ng/ml},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Ingebrigtsen, T; Romner, B; Marup-Jensen, S; Dons, M; Lundqvist, C; Bellner, J; Alling, C; Borgesen, S E
The clinical value of serum S-100 protein measurements in minor head injury: a Scandinavian multicentre study Journal Article
In: Brain Injury, vol. 14, pp. 1047–1055, 2000.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Ingebrigtsen2000,
title = {The clinical value of serum S-100 protein measurements in minor head injury: a Scandinavian multicentre study},
author = {Ingebrigtsen, T and Romner, B and Marup-Jensen, S and Dons, M and Lundqvist, C and Bellner, J and Alling, C and Borgesen, S E},
year = {2000},
date = {2000-01-01},
journal = {Brain Injury},
volume = {14},
pages = {1047--1055},
address = {Department of Neurosurgery, University Hospital of Tromso, Norway. nevktoi@rito.no},
abstract = {PURPOSE: This study of patients with minor head injury was designed to investigate the relation of S-100 protein measurements to computed tomograpy (CT) findings and patients outcomes. Increased serum levels of this protein were hypothetized to predict intracranial pathology and increased frequency of post-concussion symptoms. METHODS: One hundred and eighty-two patients were studied with Glasgow Coma Scale scores of 13-15. The study recruited patients from three Scandinavian neurotrauma centres. Serum levels of S-100 protein were measured at admittance and CT scans of the brain were obtained within 24 hours postinjury in all patients. Outcome was evaluated with the Rivermead Postconcussion Symptoms Questionnaire (RPQ) 3 months after the injury. RESULTS: Increased serum level of S-100 protein was detected in 69 (38%) patients, and CT scan demonstrated intracranial pathology in 10 (5%) (brain contusion in seven, epidural haematoma in two, traumatic subarachnoid haemorrhage in one). The proportion of patients with detectable serum level was significantly (p \< 0.01) higher among those with intracranial pathology (90%) compared to those without (35%). The negative predictive value of an undetectable S-100 level was 0.99. Sixty-two per cent reported one or more post-concussion symptoms at follow-up. A trend was observed towards an increased frequency of post-concussion symptoms among patients with detectable serum levels. CONCLUSIONS: Undetectable serum level of S-100 protein predicts normal intracranial findings on CT scan. Determination of S-100 protein in serum may be used to select patients for CT scanning. Increased S-100 serum levels may be more related to post-concussion symptoms caused by mild traumatic brain injury than to symptoms of psychological origin.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Drake Jr., M E; Weate, S J; Newell, S A
Auditory evoked potentials in postconcussive syndrome Journal Article
In: Electromyography & Clinical Neurophysiology, vol. 36, pp. 457–462, 1996.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{DrakeJr.1996,
title = {Auditory evoked potentials in postconcussive syndrome},
author = {{Drake Jr.}, M E and Weate, S J and Newell, S A},
year = {1996},
date = {1996-01-01},
journal = {Electromyography \& Clinical Neurophysiology},
volume = {36},
pages = {457--462},
address = {Department of Neurology, Ohio State University College of Medicine, Columbus, USA.},
abstract = {The neuropsychiatric sequelae of minor head trauma have been the source of controversy. Most clinical and imaging studies have shown no alteration after concussion, but neuropsychological and neuropathological abnormalities have been reported. Some changes in neurophysiologic diagnostic tests have been described in postconcussive syndrome. We recorded middle latency auditory evoked potentials (MLR) and slow vertex responses (SVR) in 20 individuals with prolonged cognitive difficulties, behavior changes, dizziness, and headache after concussion. MLR is utilized alternating polarity clicks presented monaurally at 70 dB SL at 4 per second, with 40 dB contralateral masking. Five hundred responses were recorded and replicated from Cz-A1 and Cz-A2, with 50 ms. analysis time and 20-1000 Hz filter band pass. SVRs were recorded with the same montage, but used rarefaction clicks, 0.5 Hz stimulus rate, 500 ms. analysis time, and 1-50 Hz filter band pass. Na and Pa MLR components were reduced in amplitude in postconcussion patients. Pa latency was significantly longer in patients than in controls. SVR amplitudes were longer in concussed individuals, but differences in latency and amplitude were not significant. These changes may reflect posttraumatic disturbance in presumed subcortical MLR generators, or in frontal or temporal cortical structures that modulate them. Middle and long-latency auditory evoked potentials may be helpful in the evaluation of postconcussive neuropsychiatric symptoms.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Ford, M R; Khalil, M
Evoked potential findings in mild traumatic brain injury .1. Middle latency component augmentation and cognitive component attenuation Journal Article
In: Journal of Head Trauma Rehabilitation, vol. 11, pp. 1–15, 1996.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Ford1996,
title = {Evoked potential findings in mild traumatic brain injury .1. Middle latency component augmentation and cognitive component attenuation },
author = {Ford, M R and Khalil, M},
year = {1996},
date = {1996-01-01},
journal = {Journal of Head Trauma Rehabilitation},
volume = {11},
pages = {1--15},
abstract = {Abstract: Objective: To compare evoked potential (EP) and electroencephalogram (EEG) recordings from patients with suspected mild traumatic brain injury (TBI) versus normal controls using computerized EP and EEG analysis procedures. Design: Matched two-group comparison design, with a second matched replication group, and a second group of normals. Setting: Private, ambulatory, non-emergency facility specializing in assessment, pain management, and rehabilitation of spine and related injuries. Patients and Other Participants: Patients were 54 consecutive referrals for computerized EP/EEG evaluation with histories of primarily motor vehicle accidents and symptoms consistent with mild TBI. Normal controls were 27 screened volunteers. Patients were arbitrarily divided into two groups and matched to the controls on the basis of age and gender. Main Outcome Measures: Outcome measures not included in this phase of investigation. Auditory and visual EPs were obtained in resting and P300 task sessions (in which subjects counted the number of randomly occurring target stimuli). The paucity of existing Literature did not permit prediction of all critical EP or EEG variables. Results: Middle latency EP components tie, after brain stem responses yet before long latency, cognitive components) showed amplitude increases (auditory P1, P2, and N2, and visual P2, 50-220 milliseconds poststimulus). Long latency cognitive components (auditory and visual P300 and N3, 290-700 milliseconds) showed amplitude decreases. Similar findings were present in the replication group of patients and in comparison to a second group of normal controls. Conclusions: Significant and reliable EP differences were present in patients whose histories and symptoms were consistent with mild TBI.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Roberts, M A; Manshadi, F F; Bushnell, D L; Hines, M E
Neurobehavioural dysfunction following mild traumatic brain injury in childhood: a case report with positive findings on positron emission tomography (PET) Journal Article
In: Brain Injury, vol. 9, pp. 427–436, 1995.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Roberts1995,
title = {Neurobehavioural dysfunction following mild traumatic brain injury in childhood: a case report with positive findings on positron emission tomography (PET)},
author = {Roberts, M A and Manshadi, F F and Bushnell, D L and Hines, M E},
year = {1995},
date = {1995-01-01},
journal = {Brain Injury},
volume = {9},
pages = {427--436},
address = {Department of Pediatrics, University of Iowa College of Medicine, USA.},
abstract = {The present case study describes the neurobehavioural, neurodiagnostic, and positron emission tomography (PET) scan findings in a child who sustained a whiplash-type injury in a motor vehicle accident. Although neck and back pain were reported immediately, neurobehavioural symptoms, such as staring spells, gradually increased in frequency over a 2-year period following the accident. At 4 years after the accident the patient's symptoms persisted, as reported by teachers and parents, and more extensive diagnostic work-up was initiated. Standard EEG was normal while two ambulatory EEGs were abnormal and interpreted as epileptiform. A PET scan showed evidence of marked hypometabolism in both temporal lobes. Neuropsychological findings were consistent with PET findings and reflected verbal and visual memory deficits in the context of high average intelligence. Treatment with carbamazepine, verapamil, and fluoxetine greatly improved the patient's symptoms. The present case illustrates an example of a poor outcome in a paediatric case of mild traumatic brain injury, the importance of PET in demonstrating definitive evidence of brain dysfunction, and the child's positive response to anticonvulsant medication.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Eide, P K; Tysnes, O B
Early and late outcome in head injury patients with radiological evidence of brain damage Journal Article
In: Acta Neurologica Scandinavica, vol. 86, pp. 194–198, 1992.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Eide1992,
title = {Early and late outcome in head injury patients with radiological evidence of brain damage},
author = {Eide, P K and Tysnes, O B},
year = {1992},
date = {1992-01-01},
journal = {Acta Neurologica Scandinavica},
volume = {86},
pages = {194--198},
address = {Department of Neurosurgery, Haukeland Hospital, Bergen, Norway.},
abstract = {This study examined the early and late outcome in head injury patients with focal or multifocal (unilateral or bilateral) brain contusions revealed by computerized tomography (CT) scanning. The outcome was also evaluated in patients hospitalized due to brain concussion. Three months after the injury (the early outcome) 43% of the 86 cases with multifocal contusions on the CT scan were dead. As evaluated by the Glasgow Outcome Scale, all the 57 patients with a focal brain contusion, as well as the 117 cases with brain concussion, made a good recovery or were moderately disabled. The late outcome (1 to 5 years after injury) was evaluated in 78 cases with brain contusion and in 85 cases with brain concussion, and revealed that complaints and impaired adaptive functioning were frequent in both the contusion and concussion group. The occurrence of headache, dizziness and sleep problems did not significantly differ among the various head injury groups. However, focal or multifocal brain contusions on the CT scan increased the frequency of impaired memory, impaired concentration, speech problems, weakness in arms or legs and seizures with loss of consciousness. Cognitive deficits and speech problems were particularly common in patients with a focal contusion in the temporal lobe. The late adaptive and social functioning were most markedly impaired in cases with multifocal bilateral contusions.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}
Green, J; Leon-Barth, C; Dieter, J; Benfante, P; Walker, D
Somatosensory evoked responses via electronic brain imaging (EBI) Journal Article
In: Clinical Electroencephalography, vol. 23, pp. 79–88, 1992.
Abstract | BibTeX | Tags: Imaging & EEG Physiopathology
@article{Green1992,
title = {Somatosensory evoked responses via electronic brain imaging (EBI)},
author = {Green, J and Leon-Barth, C and Dieter, J and Benfante, P and Walker, D},
year = {1992},
date = {1992-01-01},
journal = {Clinical Electroencephalography},
volume = {23},
pages = {79--88},
address = {Southeastern Neuroscience Institute, Inc., Jacksonville, FL 32207-6840.},
abstract = {This study of a series of 40 mildly head injured (concussed) patients suggests that different physiologic pathways underlying the tests done in a six-part resting EEG, and for the 11 evoked electrical potential shifts occurring in the cerebral terrain, are testable. Further work seems likely in order to ascertain which clinical signs and symptoms may be related to specific individual types of recorded electronic brain imaging (EBI) abnormality. Which of the 11 parameters studied, EEG, VER, AER, and SER, would be more or less likely to be abnormal in their individual patterns (as being deviant from normal controls) also remains to be defined. The relationship of these neurophysiologic abnormalities to certain postconcussive symptoms, i.e., headache, dizziness, blurred vision, etc., at this point in time remains to be evaluated more precisely. The authors suggest that further research is necessary in evaluating the clinical use of somatosensory evoked responses as an additional parameter in electronic brain imaging (EBI) technology.},
keywords = {Imaging \& EEG Physiopathology},
pubstate = {published},
tppubtype = {article}
}