Effect of concussion and blast exposure on symptoms after military deployment

Objective: To examine whether blast exposure alone and blast-associated concussion result in similar neurologic and mental health symptoms. Methods: A 14-item questionnaire was administered to male US Marines on their return from deployment in Iraq and/or Afghanistan. Results: A total of 2,612 Marines (median age 22 years) completed the survey. Of those, 2,320 (88.9%) reported exposure to ≥1 blast during their current and/or prior deployments. In addition, 1,022 (39.1%) reported ≥1 concussion during the current deployment, and 731 (28.0%) had experienced at least 1 prior lifetime concussion. Marines were more likely to have sustained a concussion during the current deployment if they had a history of 1 (odds ratio [OR] 1.5, 95% confidence interval [CI] 1.2-2.0) or ≥1 (OR 2.3, 95% CI 1.7-3.0) prior concussion. The most common symptoms were trouble sleeping (38.4%), irritability (37.9%), tinnitus (33.8%), and headaches (33.3%). Compared to those experiencing blast exposure without injury, Marines either experiencing a concussion during the current deployment or being moved or injured by a blast had an increased risk of postinjury symptoms. Conclusions: There appears to be a continuum of increasing total symptoms from no exposure to blast exposure plus both current deployment concussion and past concussion. Concussion had a greater influence than blast exposure alone on the presence of postdeployment symptoms. A high blast injury score can be used to triage those exposed to explosive blasts for evaluation.