David K. Ryser

Alcohol abuse and traumatic brain injury: Quantitative magnetic resonance imaging and neuropsychological outcome

Prior or concurrent alcohol use at the time of traumatic brain injury (TBI) was examined in terms of post-injury atrophic changes measured by quantitative analysis of magnetic resonance imaging (MRI) and neuropsychological outcome. Two groups of TBI subjects were examined: those with a clinically significant blood alcohol level (BAL) present at the time of injury (TBI + BAL) and those without a significant BAL (TBI-only). To explore the potential impact of both acute and chronic alcohol use, subjects in both groups were further clustered into one of four subgroups (NONE, MILD, MODERATE or HEAVY) based upon available information regarding their pre-injury alcohol use. One-way analysis of covariance (ANCOVA) and multiple analysis of covariance (MANCOVA) were used with subject grouping as the main factor. Age, injury severity as measured by Glasgow Coma Scale (GCS) score, years of education, total intracranial volume (TICV), and the number of days post-injury were included as covariates where appropriate. Increased general atrophy was observed in patients with (a) a positive BAL and/or (b) a history of moderate to heavy pre-injury alcohol use. In addition, performance on neuropsychological outcome variables (WAIS-R and WMS-R Index scores) was generally worse in the subgroups of patients with positive BAL and a history of preinjury alcohol use, as compared to the other TBI groups though not statistically significant. Implications of alcohol use, at the time of brain injury, are discussed.

Post-traumatic amnesia predicts long-term cerebral atrophy in traumatic brain injury

Primary objective: To examine post-traumatic amnesia (PTA) and its relation to long-term cerebral atrophy in persons with traumatic brain injury (TBI) using objective indicators of PTA duration and Quantitative Magnetic Resonance Imaging (QMRI). It was hypothesized that longer PTA would predict later generalized atrophy (increased ventricle-to-brain ratio (VBR)). As a guide in assessing patients with TBI, this study determined the probability of developing chronic cerebral atrophy based on PTA duration. Research design: Probability model using 60 adult patients with mild-to-severe TBI. Main outcomes and results: A logistic regression model with a cut-off determined by normative QMRI data confirmed that longer PTA duration predicts increased VBR. A probability model demonstrated a 6% increase in the odds of developing later atrophy on neuroimaging with each additional day of PTA. Conclusions: PTA has previously proven to be a good indicator of later cognitive recovery and functional outcome and also predicts long-term parenchymal change.

Day-of-injury computerized tomography, rehabilitation status, and development of cerebral atrophy in persons with traumatic brain injury.

Bigler ED, Ryser DK, Gandhi P, Kimball J, Wilde EA: Day-of-injury computerized tomography, rehabilitation status, and development of cerebral atrophy in persons with traumatic brain injury. Am J Phys Med Rehabil 2006;85:793–806. Objective:To compare day-of-injury (DOI) computerized tomography (CT) findings with acute injury severity markers, disability at acute hospital admission and discharge from inpatient rehabilitation, injury severity markers, and degree of postacute cerebral atrophy on magnetic resonance imaging (MRI). Design:Retrospective chart review of 240 consecutive traumatic brain injury (TBI) admissions (mean age 31.7 ± 15.8 yrs) with moderate-to-severe initial brain injury. All DOI CT abnormalities were qualitatively rated. Disability was assessed using the Disability Rating Scale (DRS) and the FIM measure. In a representative subset, cerebral atrophy was determined by the ventricle-to-brain ratio (VBR) method and quantified from MRI scans 25 or more days postinjury. Results:CT classification resulted in nonsignificant differences in DRS and FIM ratings at the time of discharge from the rehabilitation unit, except in brainstem injury subjects who had significantly higher DRS and lower FIM scores at rehabilitation discharge. At 25 or more days postinjury, presence of any DOI CT abnormality was associated with larger VBR. Increased VBR, as an index of cerebral atrophy, was associated with worse rehabilitation discharge DRS and FIM ratings. Conclusions:Other than brainstem injury, DOI CT findings relate poorly to rehabilitation outcome. Presence of DOI CT abnormalities were associated with the development of cerebral atrophy, which was associated with poorer rehabilitation discharge DRS and FIM scores.