As a result of ongoing military conflicts in Afghanistan and Iraq, United States service members have experienced a stark increase in the prevalence of injuries related to blast exposure (BE) from improvised and other explosive devices. Because technological advances have improved the effectiveness of protective gear, service members are more likely to survive BE and return home with serious injuries, including traumatic brain injury (TBI). To best support the care and recovery of combat veterans, clinicians are interested in discovering the mechanisms underlying BE-related TBI and the potential implications of these injuries for soldiers returning from deployment.
A team of researchers in California investigated the effects of BE on the brain structure and functioning of combat veterans. The researchers were particularly interested in the effects of BE and TBI on cognitive performance and on cortical thickness. Thought to correlate with cognitive abilities and other executive functions, cortical thickness refers to the size and thickness of the layer of gray matter that encloses the brain.
To obtain these measurements, eighty veterans with mild TBI underwent magnetic resonance imaging (MRI), a type of brain imaging, and completed a series of clinical and self-report assessments to measure neurological and psychological functioning. An analysis of these data determined that veterans who experienced BE during deployment were more likely to exhibit cortical thinning in the frontal regions of the brain, which are critical to motor and cognitive function. The researchers also found that reduced cortical thickness was associated with worse executive functioning among veterans who had experienced multiple BEs.
More than 60% of U.S. service members who were engaged in combat in the Middle East reported two or more BEs during the course of their deployment. These soldiers, particularly those who experienced TBI as a result of BE, are at high risk for cortical thinning and the resultant negative outcomes for cognitive and executive functioning, which includes important skills such as memory, impulse control, and problem solving. Veterans returning from deployment may be at high risk for cognitive and behavioral changes, and they may benefit from tailored clinical interventions to ensure that they return to a normal quality of life.
Clark EL, Merritt VC, Bigler ED, et al. Blast-exposed veterans with mild traumatic brain injury show greater frontal cortical thinning and poorer executive function. Frontiers in Neurology. (November 2018).