The Effects of Apertures on Internal Pressure Measured During Shock Wave Exposure

Blast-induced neurotrauma with no overt damage to the skull has been identified as a condition suffered by military personnel serving in Iraq and Afghanistan (Glasser 2007). Symptoms of mild blast neurotrauma include alterations in cognitive functions (memory, language, problem-solving-skills) and in emotional behavior (mood swings, depression, anxiety, emotional outbursts) (Okie 2005). Despite the improvements in helmets and body armors, many veterans returning from the war front are being diagnosed with mild blast-neurotrauma (Warden 2006). Little is known of the means by which brain injury results from exposure to blast where there is no evident physical damage to the head. This study looks at possible mechanisms of brain injury related to blast by examining how pressure transmission occurs within a skull/brain surrogate system. Investigations were carried out to resolve the variables affecting skull dynamics and their effect on pressure imparted to the brain. Testing assessed internal pressure profiles as a function of ambient overpressure, orientation of the sample to shock-front exposure, and the presence of apertures.