title: Detection of central white matter injury underlying vestibulopathy after mild traumatic brain injury.
abstract: OBJECTIVE
  To determine if central axonal injury underlies vestibulopathy and ocular convergence insufficiency after mild traumatic brain injury (TBI) by using tract-based spatial statistics (TBSS) analysis of diffusion-tensor imaging (DTI).
  
  
  METHODS
  The institutional review board approved this study, and the requirement to obtain informed consent was waived. Diffusion-tensor images were retrospectively reviewed in 30 patients with mild TBI and vestibular symptoms and 25 patients with mild TBI and ocular convergence insufficiency. Control subjects consisted of 39 patients with mild TBI without vestibular abnormalities and 17 patients with mild TBI and normal ocular convergence. Fractional anisotropy (FA) maps were generated as a measure of white matter integrity and were analyzed with TBSS regression analysis by using a general linear model. DTI abnormalities were correlated with symptom severity, neurocognitive test scores, and time to recovery with the Pearson correlation coefficient.
  
  
  RESULTS
  Compared with control subjects, patients with mild TBI and vestibular symptoms had decreased neurocognitive test scores (P < .05) and FA values in the cerebellum and fusiform gyri (P < .05). Patients with ocular convergence insufficiency had diminished neurocognitive test scores (P < .05) and FA values in the right anterior thalamic radiation and right geniculate nucleus optic tracts (P < .0001). Cerebellar injury showed an inverse correlation with recovery time (R = -0.410, P = .02). Anterior thalamic radiation injury showed correlation with decreased processing speed (R = 0.402, P < .05).
  
  
  CONCLUSIONS
  DTI findings in patients with mild TBI and vestibulopathy support the hypothesis that posttraumatic vestibulopathy has a central axonal injury component. Peripheral vestibular structures were not assessed, and a superimposed peripheral contribution may exist. DTI evaluation of central vestibular structures may provide a diagnostic imaging tool in these patients and a quantitative biomarker to aid in prognosis.
authors.affiliation: From the Department of Radiology, Division of Neuroradiology (L.M.A., K.Y., S.F.), and Department of Orthopedics, Division of Sports Medicine (M.C.), University of Pittsburgh Medical Center, 8th Floor, 8 North, Presby South Tower, 200 Lothrop St, Pittsburgh, PA 15213.
authors.forename: Lea M
authors.initials: LM
authors.lastname: Alhilali
authors.forename: Karl
authors.initials: K
authors.lastname: Yaeger
authors.forename: Michael
authors.initials: M
authors.lastname: Collins
authors.forename: Saeed
authors.initials: S
authors.lastname: Fakhran
mesh_terms: D000293:Adolescent; D000328:Adult; D016880:Anisotropy; D001930:Brain Injuries / Q000150:complications*; D016022:Case-Control Studies; D002648:Child; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005099:Exotropia / Q000209:etiology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D015601:Injury Severity Score; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009483:Neuropsychological Tests; D020127:Recovery of Function; D012189:Retrospective Studies; D015837:Vestibular Diseases / Q000175:diagnosis* / Q000209:etiology*