US Department of Defense
BLAST INJURY RESEARCH
COORDINATING OFFICE
Advancing Blast Injury Research to Protect and Heal Those Who Serve

Cumulative Blast Impulse Is Predictive for Changes in Chronic Neurobehavioral Symptoms Following Low Level Blast Exposure during Military Training


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Can Repeated Low-Level Blast Lead to Significant Cognitive Challenges?

In accordance with US Public Law 116-92, section 717, which mandates that US Department of Defense (DoD) agencies document the blast exposure of each Servicemember to inform future disability and health care decisions, researchers investigated whether cumulative measures of low-level blast (LLB) exposure could predict changes in neurobehavioral symptoms, such as headaches, dizziness, or trouble concentrating.

Testing initially involved exposing mice to repeated LLB. Under controlled conditions, LLB-exposed mice regained consciousness after anesthesia faster than sham control mice, correlating with cumulative measures of blast impulse. The study was then extended to military training environments, involving trainees, instructors, and a control group with no blast exposure. Over six weeks, all participants completed weekly Neurobehavioral Symptom Inventory (NSI) surveys to record their symptoms.

Factors of blast exposure such as peak blast overpressure, impulse, total number of blasts, time in low-level blast occupation, and time in service were analyzed using Bayesian regression modeling to identify risk factors that may increase the probability of neurobehavioral symptom changes linked to career occupational blast exposure. While multiple factors appeared to play a role, cumulative blast impulse was the most reliable predictor of changes in brain function. This finding suggests that tracking the total impulse from blasts could be critical for predicting and managing potential brain health issues.

Monitoring cumulative blast impulse enables military leaders to manage exposure effectively, balancing safety with operational readiness. The study established a link between cumulative blast impulse and neurobehavioral symptoms, supported by evidence from both animal testing and real-world military training. Servicemembers with pre-existing symptoms may be at higher risk from repeated blast exposure, underscoring the need for ongoing monitoring to prevent long-term brain health issues.


Soldier Borne Sensor (SBS) took flight
Figure 1. Talking Blast Exposure Impact with TBICoE (https://health.mil/News/Gallery/Dvids-Videos/2024/10/15/video940284) (Credit: UNITED STATES, 10.15.2024, Video by Vincent White, Defense Health Agency )

References:

Cumulative Blast Impulse Is Predictive for Changes in Chronic Neurobehavioral Symptoms Following Low Level Blast Exposure during Military Training. SFC Cory McEvoy, SFC Adam Crabtree, John Case, COL Gary E. Means, COL Peter Muench, Ronald G. Thomas, Rebecca A. Ivory, Jason Mihalik, James S. Meabon. Military Medicine: 189, 9/10: e2069, 2024, https://doi.org/10.1093/milmed/usae082


Funding:

This work was supported by the Veterans Affairs Northwest Mental Illness Research Education, and Clinical Center (JSM), a VA Biomedical Research and Development grant (JSM, I01BX004896-02), and a Congressionally Directed Medical Research TBI Psychological Health Research Program award (JSM, JPM; HT94252310755).

Last modified: 11-Mar-2025