Prevalence and Nature of Traumatic Brain Injury During Army Pre-Deployment Training

Active duty and reserve service members (SMs) are at increased risk of sustaining a traumatic brain injury (TBI). Given the high frequency of TBIs during recent military operations, much is known about combat-related TBI. Nevertheless, and notably, most recorded TBIs occur in non-deployed settings, where Soldiers regularly engage in operational training activities that mimic combat and participate in routine activities that carry TBI risk. There is sparse literature examining the risk of TBI during pre-deployment training independently from other non-combat settings. This study aimed to determine the risk of TBI during Army pre-deployment training, including both diagnosed and undiagnosed cases.

61 U.S. Army Veterans (ages 23-49, mean age = 32.5, 80% men) with at least 3 years of service, including 2 years in a combat arms branch, completed an online survey that queried demographic/basic military information and diagnosed and undiagnosed TBIs sustained during their military career, focusing on those sustained during pre-deployment training. Responses were verified for authenticity and uniqueness. Descriptive statistics, McNemar tests, and Wilcoxon signed-rank tests were used to examine the prevalence/number of training- vs. non-training-related TBIs and of diagnosed vs. undiagnosed training-related TBIs. The nature of injury, with respect to both symptoms and method of injury, was examined using descriptive statistics. A chi-square test examined the relationship between TBI setting (training vs. non-training) and diagnostic status. Penalized and unpenalized logistic and generalized linear models evaluated predictors of the presence and number of training-related TBIs generally, and both diagnosed and undiagnosed training-related cases specifically. All procedures were approved by the Drexel University Institutional Review Board.

The prevalence of pre-deployment training-related TBI (53%) was comparable to that of non-training-related TBI (56%; P = .83), and TBIs were no more or less likely to be diagnosed in training vs. non-training settings (P = 1.00). However, undiagnosed training-related TBI cases subtly outnumbered diagnosed ones (P = .045) and undiagnosed non-training related TBI was common (48%). Additionally, while common symptoms remained the same regardless of diagnostic status, causes differed. Consistent predictors of training-related TBI included having more than 1 pre-deployment training cycle and serving in the Army for over 6 years (P < .05).

This research advances understanding of TBI by providing prevalence estimates from a small, self-reported sample of Veterans in the context of military training. This knowledge may inform Army training protocols to reduce the risk of such injuries. Results should be interpreted in light of the fact that data were collected via an online, self-report measure of TBI and that narrow inclusion criteria resulted in a small sample. Nevertheless, by applying a strict definition of pre-deployment training within a Veteran population, a unique analysis of training-related TBI prevalence is offered. Future research should include a larger, more diverse sample to better understand TBI rates across the military, explore reasons for underreporting, and account for time spent in training vs. non-training environments.