Objective: The primary objective of this study is to determine the behavioral-anatomical relationships that underlie fatigue and amotivation following mild traumatic brain injury in deployed military service members. The specific aims are to 1) determine the neural correlates of fatigue, and 2) assess how fatigue and social cognition relate to social outcomes including employment, community integration and participation in social activities. The theory we will test is that fatigue in this population is the result of subtle changes in frontal cortical and subcortical structures. Study Design: Observational, natural history study. Populations: 1) Individuals who have sustained a mild traumatic brain injury as a service member deployed in support of Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn, and who continue to experience symptoms more than 6 months after injury, and 2) Companions of individuals from the first group. Outcome Measures: We will seek statistical associations between fatigue measures and brain morphometric and white matter diffusion measurements obtained by MRI as well as task and resting state fMRI.
- INCLUSION CRITERIA mTBI GROUP: - Diagnosis of at least one mTBI during deployment; - At least six months from time of injury; - Age range 18 or older; - A self-report of somatic or behavioral symptoms that developed within 3 months following mTBI and were not present before injury, and may or may not be present at enrollment: - Easy fatiguability - Sleep disturbance - Headache or other chronic widespread pain that does not seem related to extremity injury - Emotional lability - Lack of spontaneity or apathy - Lack of motivation - Feelings of anxiety - Personality change that they or others have noticed - Irritability or aggressiveness - The mTBI participant provides informed consent. EXCLUSION CRITERIA mTBI GROUP: - Daily use of stimulants, narcotics, hypnotic or anxiolytics - Diagnosis of sleep apnea, thyroid disorder, or rheumatoid arthritis - Any history of head injury associated with a loss of consciousness that lasted longer than 24 hours (not including sedation); - Daily use of more than 600mg caffeine (equivalent to approximately five cups of coffee). - Headaches more than once a month prior to deployment; - Pregnancy; - Claustrophia; - Inability to comfortably lie supine for two hours INCLUSION CRITERIA companion group - Chosen by a mTBI participant as a close companion (i.e, spends or in the last 3 years has spent a minimum of 1 hour per week on average with the mTBI participant and with whom the mTBI participant is comfortable discussing personal matters); - The companion provides informed consent. EXCLUSION CRITERIA companion group: -Lack of understanding of the English language