An update on repeated blast traumatic brain injury

Service members and law enforcement experience repeated blast exposures frequently due to the constant use of heavy weaponry, including large caliber rifles and explosives. Over the past five years, there has been growth in preclinical traumatic brain injury models of repeated exposure to blasts. While the literature is still limited, recent evidence is shedding light on potential cumulative effects and long-term consequences. In real-life scenarios, personnel experience low-level blasts extensively during training programs. In humans, low-level blasts are often not associated with overt symptoms; however, exposure to repeated low-level blasts can lead to cognitive impairments, attention deficits, and sleep disturbances over time. For this review, we focused on studies reproducing repeated blasts from 2015 to 2021. Overall, we found that repeated moderate blasts induce similar neurological changes as a single moderate blast, whereas repeated low-level blasts show a trend of neuropathological changes similar to a single moderate blast.