Age-dependent material properties of the porcine cerebrum: effect on pediatric inertial head injury criteria

During growth and development, the immature central nervous system undergoe s rapid alterations in constituents and structure. We hypothesize that thes e alterations are accompanied by changes in the mechanical properties of br ain tissue which, in turn, influence the response of the brain to traumatic inertial loads. Samples of frontal cerebrum from neonatal (2-3 days) and a dult pigs were harvested and tested within 3 h post-mortem. The complex she ar modulus of the samples was measured in a custom-designed oscillatory she ar testing device at engineering shear strain amplitudes of 2.5% or 5% from 20-200 Hz, at 25 degrees C and 100% humidity. In this range, the elastic a nd viscous components of the complex shear modulus increased significantly with the development of the cerebral region of the brain. Using an idealize d model of the developing head, the age-dependent material properties of br ain tissue were shown to affect the mechanical response of the brain to ine rtial loading. This study is a first step toward developing head injury tol erance criteria specifically for the pediatric population., (C) 1998 Elsevi er Science Ltd. All rights reserved.