Researchers from MIT and Walter Reed Army Medical Center have been using computer simulations to study how shock waves propagate around and through the head during an explosion. The idea is to help design better defenses for the scalp to prevent brain injury, and one of the outcomes of the study was the suggestion that polycarbonate face shields may help.
To create the models, Radovitzky and his students collaborated with David Moore, a neurologist at the Defense and Veterans Brain Injury Center at Walter Reed Army Medical Center, who used magnetic resonance imaging to model features of the head. The researchers then added data collected from colleagues’ studies of how the brain tissue of pigs responds to mechanical events, such as shocks. They also included details about the explosion that creates the blast wave upon detonation, including the explosive type, mass and location relative to the target.
The researchers recently used the models to explore one possibility for enhancing the helmet currently worn by most ground troops, which is known as the Advanced Combat Helmet, or ACH: a face shield made of polycarbonate, a type of transparent armor material (the helmets worn by most motorcyclists feature polycarbonate face shields). The researchers compared how the brain would respond to the same blast wave simulated in three scenarios: a head with no helmet, a head wearing the ACH, and a head wearing the ACH with a face shield. In all three simulations, the blast wave struck the person from the front.
Funded by the Joint Improvised Explosive Device Defeat Organization through the Army Research Office and the ISN, the analysis revealed that although the ACH — as currently designed and deployed — slightly delayed the arrival of the blast wave, it didn’t significantly mitigate the wave’s effects on brain tissue. However, in contrast to the results of a previous study, Radovitzky’s team found that the ACH also did not worsen the effects of the blast wave. The models showed a significant reduction in the magnitude of stresses on the brain when a face shield was employed, because the shield impeded direct transmission of blast waves to the face.
Link @ MIT: Heading off trauma …
Open Access Article in PNAS: In silico investigation of intracranial blast mitigation with relevance to military traumatic brain injury
