Mild traumatic brain injury

Symptomatic White Matter Changes in Mild Traumatic Brain Injury Resemble Pathologic Features of Early Alzheimer Dementia

Authors: Fakhran S, Yaeger K, Alhilali L.

Purpose:To evaluate white matter integrity in patients with mild traumatic brain injury (TBI) who did not have morphologic abnormalities at conventional magnetic resonance (MR) imaging with diffusion-tensor imaging to determine any relationship between patterns of white matter injury and severity of postconcussion symptoms.Materials and Methods:The institutional review board approved this study, with waiver of informed consent. Diffusion-tensor images from 64 consecutive patients with mild TBI obtained with conventional MR imaging were evaluated retrospectively. Fractional anisotropy (FA) maps were generated as a measure of white matter integrity. All patients underwent a neurocognitive evaluation. Correlations between skeletonized FA values in white matter, total concussion symptom score, and findings of sleep and wake disturbances were analyzed with regression analysis that used tract-based spatial statistics.Results:Total concussion symptom scores varied from 2 to 97 (mean ± standard deviation, 32.7 ± 24.4), with 34 patients demonstrating sleep and wake disturbances. Tract-based spatial statistics showed a significant correlation between high total concussion symptom score and reduced FA at the gray matter-white matter junction (P < .05), most prominently in the auditory cortex (P < .05). FA in the parahippocampal gyri was significantly decreased in patients with sleep and wake disturbances relative to patients without such disturbances (0.26 and 0.37, respectively; P < .05).Conclusion:The distribution of white matter abnormalities in patients with symptomatic mild TBI is strikingly similar to the distribution of pathologic abnormalities in patients with early Alzheimer dementia, a finding that may help direct research strategies.

Increased Gray Matter Diffusion Anisotropy in Patients with Persistent Post-Concussive Symptoms following Mild Traumatic Brain Injury

Authors: Bouix S, Pasternak O, Rathi Y, Pelavin PE, Zafonte R, Shenton ME.

A significant percentage of individuals diagnosed with mild traumatic brain injury (mTBI) experience persistent post-concussive symptoms (PPCS). Little is known about the pathology of these symptoms and there is often no radiological evidence based on conventional clinical imaging. We aimed to utilize methods to evaluate microstructural tissue changes and to determine whether or not a link with PPCS was present. A novel analysis method was developed to identify abnormalities in high-resolution diffusion tensor imaging (DTI) when the location of brain injury is heterogeneous across subjects. A normative atlas with 145 brain regions of interest (ROI) was built from 47 normal controls. Comparing each subject's diffusion measures to the atlas generated subject-specific profiles of injury. Abnormal ROIs were defined by absolute z-score values above a given threshold. The method was applied to 11 PPCS patients following mTBI and 11 matched controls. Z-score information for each individual was summarized with two location-independent measures: "load" (number of abnormal regions) and "severity" (largest absolute z-score). Group differences were then computed using Wilcoxon rank sum tests. Results showed statistically significantly higher load (p = 0.018) and severity (p = 0.006) for fractional anisotropy (FA) in patients compared with controls. Subject-specific profiles of injury evinced abnormally high FA regions in gray matter (30 occurrences over 11 patients), and abnormally low FA in white matter (3 occurrences over 11 subjects). Subject-specific profiles provide important information regarding the pathology associated with PPCS. Increased gray matter (GM) anisotropy is a novel in-vivo finding, which is consistent with an animal model of brain trauma that associates increased FA in GM with pathologies such as gliosis. In addition, the individualized analysis shows promise for enhancing the clinical care of PPCS patients as it could play a role in the diagnosis of brain injury not revealed using conventional imaging.

Agreement between routine emergency department care and clinical decision support recommended care in patients evaluated for mild traumatic brain injury

Authors: Korley FK, Morton MJ, Hill PM, Mundangepfupfu T, Zhou T, Mohareb AM, Rothman RE.

OBJECTIVE: Emergency department (ED) computed tomography (CT) use has increased significantly during the past decade. It has been suggested that adherence to clinical decision support (CDS) may result in a safe decrease in CT ordering. In this study, the authors quantified the percentage agreement between routine and CDS-recommended care and the anticipated consequence of strict adherence to CDS on CT use in mild traumatic brain injury (mTBI).

Characteristics of post-traumatic headaches in children following mild traumatic brain injury and their response to treatment: a prospective cohort

Authors: Kuczynski A, Crawford S, Bodell L, Dewey D, Barlow KM.

AIM: Post-traumatic headaches (PTHs) following mild traumatic brain injury (mTBI) are common; however, few studies have examined the characteristics of PTHs or their response to treatment. The aims of this study were (1) to describe the clinical characteristics of PTH in a prospective cohort of children presenting to a paediatric emergency department with mTBI, and (2) to evaluate the response of PTH to treatment.

Mild traumatic brain injury from primary blast vs. blunt forces: Post-concussion consequences and functional neuroimaging

Authors: Mendez MF, Owens EM, Reza Berenji G, Peppers DC, Liang LJ, Licht EA.

INTRODUCTION: Primary blast forces may cause dysfunction from mild traumatic brain injury (mTBI).
OBJECTIVE: To investigate the effects of primary blast forces, independent of associated blunt trauma and post-traumatic stress disorder, on sensitive post-concussive measures.
METHODS: This study investigated post-concussive symptoms, functional health and well-being, cognition, and positron emission tomography (PET) neuroimaging among 12 Iraq or Afghanistan war veterans who sustained pure blast-force mTBI, compared to 12 who sustained pure blunt-force mTBI.
RESULTS: Both groups had significantly lower scores than published norms on the Rivermead Post-Concussion Questionnaire (RPQ) and the SF36-V Health Survey. Compared to the Blunt Group, the Blast Group had poorer scores on the Paced Auditory Serial Addition Test (PASAT) and greater PET hypometabolism in the right superior parietal region. Only the Blast Group had significant correlations of their RPQ, SF36-V Mental Composite Score, and PASAT scores with specific regional metabolic changes.
CONCLUSION: This pilot study suggests that pure blast force mTBI may have greater post-concussive sequelae including deficits in attentional control and regional brain metabolism, compared to blunt mTBI. A disturbance of a right parietal-frontal attentional network is one potential explanation for these findings.

Postconcussion Syndrome After Mild Traumatic Brain Injury in Children and Adolescents Requires Further Detailed Study

Author: Butler IJ.

OBJECTIVE:  To determine the acute predictors associated with the development of postconcussion syndrome (PCS) in children and adolescents after mild traumatic brain injury. DESIGN:  Retrospective analysis of a prospective observational study. SETTING:  Pediatric emergency department (ED) in a children's hospital. PARTICIPANTS:  Four hundred six children and adolescents aged 5 to 18 years. MAIN EXPOSURE:  Closed head trauma. MAIN OUTCOME MEASURES:  The Rivermead Post Concussion Symptoms Questionnaire administered 3 months after the injury. RESULTS:  Of the patients presenting to the ED with mild traumatic brain injury, 29.3% developed PCS. The most frequent PCS symptom was headache. Predictors of PCS, while controlling for other factors, were being of adolescent age, headache on presentation to the ED, and admission to the hospital. Patients who developed PCS missed a mean (SD) of 7.4 (13.9) days of school. CONCLUSIONS:  Adolescents who have headache on ED presentation and require hospital admission at the ED encounter are at elevated risk for PCS after mild traumatic brain injury. Interventions to identify this population and begin early treatment may improve outcomes and reduce the burden of disease.

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