Concussion Mechanism: Biomechanical Perspectives

Concussions result from an impulsive force to the head induced by direct contact, inertial loading, or blast overpressure. In earlier investigations of concussion mechanisms, linear and rotational skull kinematics were correlated with injury outcomes in animal studies, where rotational acceleration was thought to be the main contributing factor to diffuse brain changes in concussion. However, there has been a lack of data confirming these concussion mechanisms in humans. In addition, since complex nonlinear brain mechanics may not be fully represented by skull kinematics alone, recent work has focused on applying analytical and computational modeling techniques to simulate brain tissue and microstructural mechanics. As a widely applied computational tool, finite element modeling of the human skull and brain can be used to extract parameters including strain, strain rate, and pressure during injurious head loading, which are promising predictors of concussion risk. With the advancement in wearable sensors, there are ongoing research efforts to gather real-world human head kinematics and pressure exposure data from scenarios with high incidence of injury. These human data can be combined with modeling tools to test injury mechanism hypotheses and to validate criteria for predicting human brain injuries. Furthermore, emerging neuroimaging and in vitro experimental techniques as well as multiscale mechanical modeling tools could significantly contribute to the holistic understanding of brain injury biomechanics by enabling the direct investigation of microstructural changes in neural tissue.