Evaluation of Environmental Sensors During Laboratory Direct and Indirect Head Exposures

With the prevalence of traumatic brain injury (TBI) in the military and athletics, several commercial and military environmental sensors (ES) have been developed to quantify head impact exposures. The performance of five ES in controlled laboratory exposures from direct and indirect loadings, and the effect on impact protection and dynamic retention of the worn Advanced Combat Helmet (ACH) was evaluated. Direct impacts were conducted on a drop tower and indirect impacts used a mini-sled. The ES data were compared with laboratory sensors through cross-correlation and comparison of peak values. The effects of ES on dynamic retention were assessed using a one-way ANOVA with Tukey's post hoc analysis against baseline ACH performance. Two ES provided data during the blunt impact tests: one, attached to the side of the headform, correlated well (φ > 0.92) with the laboratory data; the other, mounted in the helmet crown, calculated peak headform velocity, which predicted laboratory velocity well. During indirect impact tests, one environmental sensor (attached to the side of the headform) provided usable data, which correlated well (φ > 0.92) with laboratory data. The inclusion of the environmental sensors did not introduce any safety hazards during the blunt impact attenuation tests or the dynamic retention tests.