title: Symptomatic white matter changes in mild traumatic brain injury resemble pathologic features of early Alzheimer dementia.
abstract: OBJECTIVE
  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.
  
  
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Radiology, University of Pittsburgh School of Medicine, 200 Lothrop St, Presby South Tower, 8th Floor, 8 North, Pittsburgh, PA 15213.
authors.forename: Saeed
authors.initials: S
authors.lastname: Fakhran
authors.forename: Karl
authors.initials: K
authors.lastname: Yaeger
authors.forename: Lea
authors.initials: L
authors.lastname: Alhilali
mesh_terms: D000293:Adolescent; D000328:Adult; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000473:pathology*; D001924:Brain Concussion / Q000453:epidemiology* / Q000473:pathology*; D002648:Child; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D010414:Pennsylvania / Q000453:epidemiology; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D055815:Young Adult