A recently published memorandum by the U.S. Deputy Secretary of Defense expresses the new policy of the DoD to mitigate and track blast overpressure (BOP) exposures. [1]
This is an important step in both the recognition of the adverse effects repeated blast overpressure exposure can have on brain health, but also on performance. The memorandum repeatedly highlights new policies that evaluate cognitive function in Active Duty and Reservists.
Notably absent from the memo is recognition of the potential impact BOP exposures have on mental health and sensorimotor capabilities. This is a significant omission as these areas of health and performance not only impact warfighter quality of life, but lethality.
Additionally, this establishes an interim BOP safety threshold of 4 psi. Though they recognize 4 psi is based on “evolving medical science”, this threshold value dates back to a 1966 publication that established 4 psi as the threshold that the unprotected eardrum can rupture. [1-3]
It is not based on neurotrauma.
“While this threshold is not based on the risk of neurotrauma nor on the cumulative exposure of repetitive blasts, it is relevant as it is referenced in most LLB [low-level blast] studies and is used by the U.S. Army to calculate the minimum safe distance for explosive breaching.” [3]
These new DOD requirements for managing brain health risks from blast overpressure are significant, and an enormous step in the right direction. We should take a moment and appreciate this as a win.
But significant gaps remain. There’s more work to do…
References:
- https://media.defense.gov/2024/Aug/09/2003521276/-1/-1/1/DEPARTMENT-OF-DEFENSE-REQUIREMENTS-FOR-MANAGING-BRAIN-HEALTH-RISKS-FROM-BLAST-OVERPRESSURE-OSD005281-24-RES-FINAL.PDF
- Hirsch, F. G. (1966). Effects of overpressure on the ear: a review.
- Woodall, J. L., Sak, J. A., Cowdrick, K. R., Bove Muñoz, B. M., McElrath, J. H., Trimpe, G. R., … & Hutchinson, C. R. (2023). Repetitive low-level blast exposure and neurocognitive effects in army ranger mortarmen. Military Medicine, 188(3-4), e771-e779.