The Pentagon is taking new steps to protect troops' brain health, including mandating baseline cognitive tests for all new recruits starting next year to make it easier to diagnose traumatic brain injuries later on in their career.
In a memo released on Friday, Deputy Defense Secretary Kathleen Hicks also directed the services to try to increase the distance between personnel and weapon blasts during training exercises to minimize exposure.
Protective equipment should also be provided to anyone firing certain weapons, including instructors, she wrote.
The move comes nine months after a United States Army Reservist Robert Card went on a shooting rampage at a local bar and a bowling alley in Lewiston, Maine, and killed 18 people and injured 13 more.
MORE: Maine mass shooter 'likely' suffered from traumatic brain injury: ReportA post-mortem study of Card's brain by a center at Boston University and shared by Card's family found it was "likely" he suffered from traumatic brain injury.
Card had been a U.S. Army Reservist and a longtime instructor at an Army hand grenade training range, and it was believed that he was exposed to thousands of low-level blasts, according to doctors at Boston University's Concussion Legacy Foundation.
"Blast overpressure is one of many factors that can negatively affect warfighter brain health," wrote Hicks in a statement, which said her directive "builds on existing efforts" across the services to "mitigate the impacts of blast overpressure."
Brain health effects from "blast overpressure" isn't yet fully understood by researchers, which Hicks acknowledged in her memo. But researchers agree repeated exposure can impact a person's brain health and cognitive performance, causing such ailments as headaches, attention difficulty and memory loss.
MORE: What to know about Walz's military record and Vance's accusations of 'stolen valor'Baseline brain tests are intended to make it easier to diagnose a brain injury by comparing what the brain looked like before a blast exposure.
Currently, the military only gives baseline cognitive testing to troops ahead of a deployment. But that approach wouldn't detect injuries from training.
The new Pentagon policy now mandates baseline testing for anyone entering service after Dec. 31. Active-duty troops already serving will receive baseline testing by the end of 2025, in addition to the new requirements for creating maximum distance between personnel and blast waves during training.
"This policy is not meant to preclude or unreasonably restrict commanders from conducting mission-essential weapons training," Hicks wrote in the memo. "Rather, this policy establishes requirements for practical risk management actions to mitigate and track [blast overpressure] BOP exposures across the DoD."