To address the relationship of clinical symptoms and the location and magnitude of brain strains, the Wayne State University human head finite element model was used with loading conditions predicted to produce either mild (AIS 1) or classical (AIS 2) concussion. Sinusoidal accelerations using 3,000 rad/s2 at 25 rad/s or 4,500 rad/s2 at 50 rad/s, respectively were applied in sagittal and coronal planes to evaluate the effect of loading directions on strain magnitudes and distribution. High principal strains began at the surface and later migrated subcortically, eventually maximizing in parietal cortex, basal ganglia, thalamus and parahippocampal areas. Strain magnitude increased as angular velocity increased and peaked 8 ms after the peak of angular velocity. Large principal strains were in caudate, thalamus, midbrain and hippocampus for coronal and corpus callosum, hippocampus and fronto-temporal cortex for sagittal loading. In AIS 1 concussion, peak strain in all brain regions was <0.30 while in AIS 2 concussion, large areas had strains & gt;0.35 (especially the brainstem-thalamic and hippocampal regions). These areas seem to correlate well with observed clinical symptoms of memory dysfunction and altered awareness associated with concussion.
Keywords:
brains, accelerations, finite element method, tolerances