Toward a biomechanical criterion for functional brain injury.

This paper describes a clinically relevant experimental brain injury model developed at General Motors Research Laboratories (GMRL) for biomechanical and neurophysiological studies to determine tissue-level criterial for functional neural injury. The controlled cortical contusion technique has several advantages over previous techniques for development of brain injury criteria: (1) the mechanical input to the brain tissue is controlled and can be well-characterized, a necessary step toward validation of finite element analysis procedures; (2) the neuropathologic features simulate key aspects of clinical brain injury; and (3) the functional outcome can be varied across the clinical spectrum, from minimal effect through prolonged coma to fatal, a feature critical to successful development of functional brain injury criteria. Finite element model (FEM) development and analysis is proceeding in parallel for the experimental injury model and for human brain, since geometric differences in brain structures prevent a straightforward scaling of injury thresholds based on dimension or mass. Analysis of the experimental injury event using the FEM presently allows qualitative (better/worse) assessments, and validation of the FEM model and its interpretation against observations in experimental models of brain injury will be used to define injury probability thresholds. (A) For the covering abstract of the conference, see IRRD 837684.