Untangling the Effect of Head Acceleration on Brain Responses to Blast Waves

Abstract

Multiple injurycausing mechanisms, such as wave propagation, skull flexure, cavitation, and head acceleration, have been proposed to explain blastinduced traumatic brain injury (bTBI). An accurate, quantitative description of the individual contribution of each of these mechanisms may be necessary to develop preventive strategies against bTBI. However, to date, despite numerous experimental and computational studies of bTBI, this question remains elusive. In this study, using a twodimensional (2D) rat head model, we quantified the contribution of head acceleration to the biomechanical response of brain tissues when exposed to blast waves in a shock tube. We compared brain pressure at the coup, middle, and contrecoup regions between a 2D rat head model capable of simulating all mechanisms (i.e., the alleffects model) and an accelerationonly model. From our simulations, we determined that head acceleration contributed 36–45% of the maximum brain pressure at the coup region, had a negligible effect on the pressure at the middle region, and was responsible for the low pressure at the contrecoup region. Our findings also demonstrate that the current practice of measuring rat brain pressures close to the center of the brain would record only twothirds of the maximum pressure observed at the coup region. Therefore, to accurately capture the effects of acceleration in experiments, we recommend placing a pressure sensor near the coup region, especially when investigating the acceleration mechanism using different experimental setups.