Both
traumatic brain injury (TBI) and
posttraumatic stress disorder (
PTSD) are common problems resulting from military service, and both have been associated with increased risk of
cognitive decline and
dementia resulting from
Alzheimer's disease (AD) or other causes. This study aims to use imaging techniques and
biomarker analysis to determine whether
traumatic brain injury (TBI) and/or
PTSD resulting from combat or other
traumas increase the risk for AD and decrease cognitive reserve in Veteran subjects, after accounting for age. Using military and Department of Veterans Affairs records, 65 Vietnam War veterans with a history of moderate or severe TBI with or without
PTSD, 65 with ongoing
PTSD without TBI, and 65 control subjects are being enrolled in this study at 19 sites. The study aims to select subject groups that are comparable in age, gender, ethnicity, and education. Subjects with
mild cognitive impairment (MCI) or
dementia are being excluded. However, a new study just beginning, and similar in size, will study subjects with TBI, subjects with
PTSD, and control subjects with MCI. Baseline measurements of cognition, function, blood, and cerebrospinal fluid
biomarkers; magnetic resonance images (structural, diffusion tensor, and resting state blood-level
oxygen dependent (BOLD) functional magnetic resonance imaging); and
amyloid positron emission tomographic (PET) images with
florbetapir are being obtained. One-year follow-up measurements will be collected for most of the baseline procedures, with the exception of the lumbar puncture, the PET imaging, and
apolipoprotein E genotyping. To date, 19 subjects with TBI only, 46 with
PTSD only, and 15 with TBI and
PTSD have been recruited and referred to 13 clinics to undergo the study protocol. It is expected that cohorts will be fully recruited by October 2014. This study is a first step toward the design and statistical powering of an AD prevention trial using at-risk veterans as subjects, and provides the basis for a larger, more comprehensive study of
dementia risk factors in veterans.