title: Brain Volume, Connectivity, and Neuropsychological Performance in Mild Traumatic Brain Injury: The Impact of Post-Traumatic Stress Disorder Symptoms.
abstract: Post-traumatic stress disorder (PTSD) is commonly associated with mild traumatic brain injury (mTBI). To better understand their relationship, we examined neuroanatomical structures and neuropsychological performance in a sample of individuals with mTBI, with and without PTSD symptoms. Thirty-nine subjects with mTBI were dichotomized into those with (n = 12) and without (n = 27) significant PTSD symptoms based on scores on the PTSD Checklist. Using a region-of-interest approach, fronto-temporal volumes, fiber bundles obtained by diffusion tensor imaging, and neuropsychological scores were compared between the two groups. After controlling for total intracranial volume and age, subjects with mTBI and PTSD symptoms exhibited volumetric differences in the entorhinal cortex, an area associated with memory networks, relative to mTBI-only patients (F = 4.28; p = 0.046). Additionally, subjects with PTSD symptoms showed reduced white matter integrity in the right cingulum bundle (axial diffusivity, F = 6.04; p = 0.020). Accompanying these structural alterations, mTBI and PTSD subjects also showed impaired performance in encoding (F = 5.98; p = 0.019) and retrieval (F = 7.32; p = 0.010) phases of list learning and in tests of processing speed (Wechsler Adult Intelligence Scale Processing Speed Index, F = 12.23; p = 0.001; Trail Making Test A, F = 5.56; p = 0.024). Increased volume and white matter disruptions in these areas, commonly associated with memory functions, may be related to functional disturbances during cognitively demanding tasks. Differences in brain volume and white matter integrity between mTBI subjects and those with mTBI and co-morbid PTSD symptoms point to neuroanatomical differences that may underlie poorer recovery of mTBI subjects who experience PTSD symptoms. These findings support theoretical models of PTSD and its relationship to learning deficits.
authors.affiliation: 1 Center for Neuroscience and Regenerative Medicine, National Institutes of Health , Bethesda, Maryland.
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Lopez
authors.affiliation: 2 Rehabilitation Medicine Department, Clinical Center, National Institutes of Health , Bethesda, Maryland.
authors.forename: Jacob B
authors.initials: JB
authors.lastname: Leary
authors.affiliation: 1 Center for Neuroscience and Regenerative Medicine, National Institutes of Health , Bethesda, Maryland.
authors.forename: Dzung L
authors.initials: DL
authors.lastname: Pham
authors.affiliation: 1 Center for Neuroscience and Regenerative Medicine, National Institutes of Health , Bethesda, Maryland.
authors.forename: Yi-Yu
authors.initials: YY
authors.lastname: Chou
authors.affiliation: 1 Center for Neuroscience and Regenerative Medicine, National Institutes of Health , Bethesda, Maryland.
authors.forename: John
authors.initials: J
authors.lastname: Dsurney
authors.affiliation: 1 Center for Neuroscience and Regenerative Medicine, National Institutes of Health , Bethesda, Maryland.|2 Rehabilitation Medicine Department, Clinical Center, National Institutes of Health , Bethesda, Maryland.
authors.forename: Leighton
authors.initials: L
authors.lastname: Chan
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging*; D001924:Brain Concussion / Q000000981:diagnostic imaging* / Q000523:psychology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000000981:diagnostic imaging*; D009483:Neuropsychological Tests; D009929:Organ Size; D011597:Psychomotor Performance / Q000502:physiology; D013313:Stress Disorders, Post-Traumatic / Q000000981:diagnostic imaging* / Q000523:psychology
keywords: DTI; head injury; learning; memory network; white matter integrity