John Stephen Crowley, M.D., MPH; U.S. Army Aeromedical Research Laboratory PRMRP Investigator-Initiated Research Award

Our research is focused on improving blunt head injury protection for military paratroopers. Less than half of 1% of all combat jumps result in injury, and a small portion of those are to the head and because military jumps hundreds of thousand times a year that results in a lot of head injuries due to parachuting. Combat paratroopers need to be ready for action when they land so the helmet that they use is a combat helmet designed to protect against ballistic trauma or fragments that has not blunt injury protection requirement and consequently it doesn't protect very well in closed head injury. Through our experience with aviation crashes and protecting pilots from closed head injury, we believe we can improve the helmet use by combat paratroopers by modifying the liners. We've tested over 25 different configurations of helmet liners using off-the-shelf materials and some new development materials and came up with two configurations that improved blunt impact protection by 20-40% depending on where on the helmet the impact is. We assess two aspects of performance--blunt impact protection which we measure on a standard monorail drop tower where the helmet is dropped down and impacted on an anvil of various shapes and the other aspect is dynamic retention where we use a miniature sled that we've developed where this large red impactor hits the sled and propels the sled down the rail and we look at how well the helmet stays on the head form during that sequence. What we see here is a comparison of the blunt impact protection provided by the 3 helmets. This is the existing PASGT helmet, the basic combat helmet, and our 2 experimental helmets so we can see how much b and c reduced the forces transferred to the head form in our laboratory tests. Similarly these graphs show that the experimental helmets are retained better on the soldiers' heads which is important on a crash sequence. We took those helmets to Ft. Bragg and fielded them with operational troops and sought their opinions and found that they liked 1 of our 2 helmets much better than our existing helmet the PASGT helmet. The new helmet used the same impact absorption material as the Army's new advanced combat helmet we then compared the advanced combat helmet with the old PASGT helmet in a series of survey studies and we found that they preferred the new helmet 10 times more than they preferred the old helmet. We also found that the risk of traumatic brain injury while wearing the older helmet was 2.3 times higher than while wearing the new helmet. We found that we could improve the blunt head injury protection provided by the standard combat helmet thus reducing blunt head injury for paratroopers. The funding that we received from CDMRP allowed us to design a helmet that would improve on the basic combat helmet. To take that helmet and qualify it for use by airborne troops in actual military jumps and then to evaluate that helmet in field use with operational paratroopers. This project began as an attempt to improve blunt head injury protection for paratroopers. But because blunt head injury is so common in Iraq and Afghanistan, the results of this study have helped validate the deployment of advance combat helmet which is now deployed worldwide in reducing blunt head injury to reducing soldiers in Iraq and Afghanistan.