Neuropsychological outcome and diffusion tensor imaging in complicated versus uncomplicated mild traumatic brain injury.
This study examined whether intracranial neuroimaging abnormalities in those with mild traumatic brain injury (MTBI) (i.e., "complicated" MTBIs) are associated with worse subacute outcomes as measured by cognitive testing, symptom ratings, and/or diffusion tensor imaging (DTI). We hypothesized that (i) as a group, participants with complicated MTBIs would report greater symptoms and have worse neurocognitive outcomes than those with uncomplicated MTBI, and (ii) as a group, participants with complicated MTBIs would show more Diffusion Tensor Imaging (DTI) abnormalities. Participants were 62 adults with MTBIs (31 complicated and 31 uncomplicated) who completed neurocognitive testing, symptom ratings, and DTI on a 3T MRI scanner approximately 6-8 weeks post injury. There were no statistically significant differences between groups on symptom ratings or on a broad range of neuropsychological tests. When comparing the groups using tract-based spatial statistics for DTI, no significant difference was found for axial diffusivity or mean diffusivity. However, several brain regions demonstrated increased radial diffusivity (purported to measure myelin integrity), and decreased fractional anisotropy in the complicated group compared with the uncomplicated group. Finally, when we extended the DTI analysis, using a multivariate atlas based approach, to 32 orthopedic trauma controls (TC), the findings did not reveal significantly more areas of abnormal DTI signal in the complicated vs. uncomplicated groups, although both MTBI groups had a greater number of areas with increased radial diffusivity compared with the trauma controls. This study illustrates that macrostructural neuroimaging changes following MTBI are associated with measurable changes in DTI signal. Of note, however, the division of MTBI into complicated and uncomplicated subtypes did not predict worse clinical outcome at 6-8 weeks post injury.
Department of Psychiatry, University of British Columbia, Vancouver, Canada.
William J
WJ
Panenka
Department of Psychiatry, University of British Columbia, Vancouver, Canada; Defense and Veterans Brain Injury Center, Walter Reed National Military Medical Center, Bethesda, Maryland, United States of America.
Rael T
RT
Lange
Psychiatry Neuroimaging Laboratory, Brigham Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.
Sylvain
S
Bouix
Department of Radiology, University of British Columbia, Vancouver, Canada.
Jason R
JR
Shewchuk
Department of Radiology, University of British Columbia, Vancouver, Canada.
Manraj K S
MK
Heran
Department of Emergency Medicine, University of British Columbia, Vancouver, Canada.
Jeffrey R
JR
Brubacher
Psychiatry Neuroimaging Laboratory, Brigham Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.
Ryan
R
Eckbo
Psychiatry Neuroimaging Laboratory, Brigham Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America; VA Boston Healthcare System, Brockton, Massachusetts, United States of America.
Martha E
ME
Shenton
Department of Psychiatry, University of British Columbia, Vancouver, Canada; Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, & Red Sox Foundation and Massachusetts General Hospital Home Base Program, Boston, Massachusetts, United States of America.
Grant L
GL
Iverson
D000328:Adult; D016880:Anisotropy; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D001930:Brain Injuries / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D003072:Cognition Disorders / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D038223:Post-Concussion Syndrome / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology