The Effects of Low-level Repetitive Blasts on Neuropsychological Functioning
Technical Report,29 Sep 2009,28 Mar 2014
U.S. Army Aeromedical Research Laboratory Fort Rucker United States
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Despite increased research on blast-related mild traumatic brain injury mTBI, relatively little is understood about long-term symptomatology. The primary objective of this study was to determine whether repeated exposure to low-level controlled blasts produces observable changes in cognitive functioning and psychological health. The target group was U.S. Marines i.e., breacher instructors who are regularly exposed to controlled blasts as part of their instruction at a breacher training course. In our initial assessment, breacher instructors were administered neuropsychological health questionnaires and a comprehensive computer-based neurocognitive test battery and compared to a control group of Marine instructors i.e., instructors at other training schools who are not exposed to controlled blasts. Breacher instructors reported less depression, stress, and post-traumatic stress disorder symptoms compared to control instructors, but they did not differ in performance across any of the neurocognitive domains that were measured. As a follow-up to this initial assessment, breacher instructors were repeatedly administered the neurocognitive test battery over the course of two years. Importantly, testing only occurred during the down time in the weeks between each breacher course. The results suggest that neurocognitive performance in breacher instructors remains relatively stable over time. Longitudinal cognitive performance among breacher instructors did not differ from a control group of breacher engineers i.e., support staff who are not exposed to blasts who were similarly assessed. The findings from the current study suggest that Marine breacher instructors do not suffer from long-term neurocognitive impairments due to repetitive low-level blast exposure.