Multiple traumatic brain injury and concussive symptoms among deployed military personnel.

Objective: To identify if concussive symptoms occur with greater frequency among military personnel with multiple lifetime TBIs and if a history of TBI increases risk for subsequent TBI.

Methods: One hundred and sixty-one military personnel referred to a TBI clinic for evaluation and treatment of suspected head injury at a military clinic in Iraq. Methods: Military patients completed standardized self-report measures of concussion, depression and post-traumatic stress symptoms; clinical interview; and physical examination. Group comparisons were made according to number of lifetime TBIs and logistic regression was utilized to determine the association of past TBIs on current TBI.

Results: Patients with one or more previous TBIs were more likely to report concussion symptoms immediately following a recent injury and during the evaluation. Although differences between single and multiple TBI groups were observed, these did not reach the level of statistical significance. A history of any TBI increased the likelihood of current TBI diagnosis, but this relationship was no longer significant when adjusting for injury mechanism, depression and post-traumatic stress symptoms.

Conclusions: Among deployed military personnel, the relationship of previous TBI with recent TBI and concussive symptoms may be largely explained by the presence of psychological symptoms.