Blast Physics Peer Review Means Better Helmet Design

Traumatic Brain Injury (TBI) is perhaps the defining injury of the US wars in Iraq and Afghanistan. The Military Health System diagnosed TBI in 43,779 patients between 2003 and 2007.

TBI victims suffer from a stunning range of functional brain changes both immediately after the trauma, and decades later. Memory, language, learning, emotion, and behavior are skewed. TBI can cause phantom sensation, and epilepsy; a brain injury event seems to increase the risk for Alzheimer's disease, Parkinson's, and other age-associated brain disorders.

As devastating to individuals, families, and society as TBI is, the biomechanical mechanisms describing what happens when a blast-wave meets a human head are not clearly understood. But, in 2007, SPARS recruited neurophysiologists and blast experts to review research that sought to describe how blast wave energy is transferred to a human head at different blast strengths and different head angles, addressing this knowledge gap.

Successfully funded, that research went on to explain mathematically that shock waves can be focused in the orbital cavities - the eye sockets - and the strength of the blast significantly increased by 10 times or more, "...focused like a parabolic mirror, like the headlights of a car," said the study PI.

The model showed that the blast hits the inner part of a soldier’s helmet, travels through the space between the head and helmet, then washes up and over to hit the back of the soldier’s head. With information directly from SPARS peer-reviewed research, the shape of helmets may be changed to mitigate this wave.

Further, associated research was able to use the original data to continue to describe the physiology of blast-induced brain injury - "...not just what happens in the instant of the blast impact," says the PI, "but what goes on in the brain after the blast for minutes, even hours." guiding immediate treatment and subsequent therapy.