Controlled blast exposure during forced explosive entry training and mild traumatic brain injury.

BACKGROUND There is a paucity of data regarding the pathophysiology and short- and long-term neurologic consequences of primary blast injury in humans. The purpose of this investigation was to test the feasibility of implementing a research protocol in the context of a forced explosive entry training course. METHODS Instructors (n = 4) and students (n = 10) completing the Police Explosives Technicians-Forced Entry Instructors course were recruited to participate in the study. Participants underwent a physical examination, tests of postural stability and vestibular ataxia, and a neurocognitive battery 1 day before and 10 days following practical forced explosive entry exercises. RESULTS The instructors reported significantly more blast exposures in their careers than the students (p < 0.05). Seventy-five percent of the instructors and 50% of the students reported a history of trauma to the head. A minority of the participants had deficits on cranial nerve, vestibular ataxia, and neurocognitive tests which did not change significantly postexposure. All the instructors and most of the students (90%) demonstrated postural stability deficits at baseline which did not change significantly postexposure. CONCLUSIONS Studying the effects of blast exposure on the human brain in a controlled experimental setting is not possible. Forced explosive entry training courses afford an opportunity to begin examining this issue in real time in a controlled setting. This study underscores the importance of baseline testing of troops, of the consideration of subclinical implications of blast exposure, and of continued studies of the effects of blast exposures, including repeated exposures on the human brain.