Deployment-Related Mild Traumatic Brain Injury (mTBI): Incidence, Natural History, and Predictors of Recovery in Soldiers Returning from OIF/OEF

TECHNICAL ABSTRACT

Preliminary analyses of data from large samples of non-medically evacuated soldiers returning from deployment in Iraq and Afghanistan who screened for traumatic brain injury (TBI) indicate that as many as 14% to 23% sustained TBI while deployed and that almost all of these TBI were mild (MTBI). MTBI is the most common form of TBI in both military and civilian populations; however, little reliable research on the incidence of MTBI and its long-term effects on individuals has been performed, especially in military populations. Research on civilians suggests that recovery from MTBI can take from a few days to 3 months. Screening of soldiers returning from Iraq and Afghanistan suggests that 39% to 50% of those who had MTBI while deployed report at least one persistent symptom 3 to 6 months after injury. The high prevalence of persisting MTBI-related symptoms in these returning soldiers raises a number of important questions: (1) What is the long-term symptom trajectory associated with MTBI in these returning soldiers? (2) What aspects of the deployment experience are associated with persistent sequelae? (3) Do these sequelae have measurable long-term impacts on work performance and quality of life? (4) Do the screening tools currently in use correctly identify soldiers with deployment-related MTBI?

This study has three objectives: (1) determine the incidence and natural history of MTBI, including symptom trajectory and specific symptom complexes, in a large and carefully followed sample of recently deployed soldiers; (2) characterize the symptom complexes associated with MTBI alone, MTBI combined with post-traumatic stress disorder (PTSD), and determine the base rates of MTBI-like symptoms among soldiers who screen negative for both MTBI and PTSD; (3) determine the risk factors for poor recovery; (4) determine the amount of burden poor recovery places on individual soldiers and the Army; and (5) assess the validity of the tools currently used to screen returning soldiers for deployment-related TBI. The specific aim of this study is to provide high-quality epidemiologic evidence about the incidence and long-term effects of deployment-related MTBI that will enable Army health care providers to efficiently deliver the appropriate treatment to soldiers who need them.

A total of 750 soldiers returning from deployment to Fort Bragg and Fort Carson who screen positive for deployment-related MTBI and who agree to participate, as well as 750 returning soldiers who screen negative and who agree to participate, will receive a comprehensive baseline assessment, including a clinical evaluation, cognitive testing, TBI symptom screening, and a PTSD assessment. They will then be interviewed 3 months, 6 months, and 12 months following the baseline assessment to obtain longitudinal data about TBI symptom levels, work status and performance, and quality of life. We will also search military databases for additional information about the participants' work performance as well as medical care they received after returning from deployment.