Structural and Functional Neuroimaging Studies of Combat Veterans

Objective: Traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD) are linked with functional impairments, poor outcomes compared to matched controls or people without brain dysfunction, and greater healthcare utilization. TBI can be diagnosed at the point of injury, but post-concussive syndrome (PCS) and PTSD are diagnosed after the initial exposure. Current treatments are often ineffective, and many affected military service members (SMs) never return to active duty. Upon return from deployment, many SMs experience an initial honeymoon period during which symptoms are limited in number and scope, but this may be followed by a sharp increase in symptoms within months. Identification of independent predictors of PTSD and PCS upon return from deployment could facilitate early intervention to prevent disability. The main purpose of this protocol is to determine whether structural and functional neuroimaging in SMs who are ostensibly healthy upon return can differentiate those who will go on to have persistent neurocognitive difficulties from those who will not. Study population: The study population will be returning SMs at risk for PCS or PTSD. It involves a prospective cohort study of 128 healthy active duty military SMs, recruited by the Walter Reed National Military Medical Center (WRNMMC) from National Capital Area military units within 8 weeks after return from Iraq or Afghanistan, with serial evaluations to identify both those who develop PTSD or PCS, as well as factors obtained at the time of the initial evaluation that prove to be most strongly associated with subsequent PTSD and PCS. A comprehensive baseline assessment will be performed at WRNMMC under protocol 351030 (already approved at both the Uniformed Services University of Health Sciences \[USUHS\] and WRNMMC), which will include demographics, neuropsychological assessment, genetic and neuroendocrine assays, brain imaging and synchronization, vestibular, olfactory, and psychophysiologic measures. Neuroimaging and fMRI activation tasks will be performed under this imaging protocol at NIH. The study is funded by the USUHS Center for Neuroscience and Regenerative Medicine (CNRM) and NIH. See the attached WRNMMC protocol 351030. Design: Neuroimaging including structural and functional magnetic resonance imaging (fMRI), and diffusion tension imaging (DTI) will be performed under this imaging protocol at NIH. Follow-up visits at 3, 6, and 12 months will allow repeated MRIs and fMRI activation tasks. Data analysis will include serial univariate and multivariate analyses to identify the baseline measures (including not only the results from this imaging study at NIH but also the results from a variety of studies to be performed at WRNMMC) that are most strongly associated with the subsequent development of PTSD and PCS. Outcome measures: The primary outcome of interest is the development of neurocognitive difficulties (PCS, PTSD, or depression). Multivariate analyses will assess what baseline measures are most strongly associated with this outcome.