Adding a face shield to the standard-issue helmet worn by U.S. troops could help protect soldiers from traumatic brain injury, the signature wound of the recent wars in Iraq and Afghanistan. A new study that models how shock waves pass through the head finds that adding a face guard deflects a substantial portion of the blast that otherwise would steamroll its way through the brain.
The study, to appear in the Proceedings of the National Academy of Sciences, is part of a spate of new work tackling traumatic brain injury. An estimated 1.5 million Americans sustain mild traumatic brain injury each year, and nearly 200,000 service members have been diagnosed with it since 2000, according to the Armed Forces Health Surveillance Center in Silver Spring, Md. While direct impact, such as banging the head, clearly can injure the brain, the forces endured when explosives send shock waves crashing through the head are much more difficult to characterize.
In the new study, researchers led by Raúl Radovitzky of MIT’s Institute for Soldier Nanotechnologies created an elaborate computer model of a human head that included layers of fat and skin, the skull, and different kinds of brain tissue. The team modeled the shock wave from an explosion detonated right in front of the face under three conditions: with the head bare, protected by the currently used combat helmet and covered with the helmet plus a polycarbonate face shield.