Comparison and Characterization of Different Concussive Brain Injury Events

Abstract

Concussions are debilitating injuries affecting the short and long-term health of those who suffer from them. While an increased awareness of the injury has helped lead to a better understanding of the importance of better monitoring and treatment protocols, concussive injuries continue to occur at an alarming rate. Current injury risk thresholds exist and are used in the development of better equipment to protect athletes in high impact sports, however much of this data is based on simulations and/or cadaveric and animal model data from falls. Thus, there is a lack of data from concussive injuries resulting from a multitude of injury events within different sports, including collisions, falls and punches. The purpose of this thesis was to use dynamic response characteristics and brain tissue response to compare four different injury events from reconstructions of real life concussive injury events. This research was designed to provide information related to brain trauma characteristics specific to four common concussive brain injury events. Seventy-two (72) injury reconstructions were used in this study involving four injury events; collisions, helmeted falls, unhelmeted falls and punches. The results from the first study revealed that while all injury events produced similar MPS and Von Mises stress values, the injury events produced different peak linear and rotational accelerations. In terms of risk for concussive injury, differences were also found between percent risk for concussion and the specific injury events, questioning the validity of current concussive thresholds’ applicability to across all types of concussive injury events. The second study aimed to characterize each concussive injury event by means of specific kinematic characteristics unique to that particular event. The results showed that dynamic response variables that accounted for the most variance changed dependant on the concussive producing event. The third study compared maximal principle strain and strain fields within the brain by the specific injury event. The results showed that global strain within specific regions of the brain were significantly different between the different injury events. Furthermore, unique strain fields within the cerebrum were found between the four concussive injury events. The three studies in this research program characterize four common concussive injury events found in sport. It aimed to describe the unique dynamic response characteristics for each injury event that may have significant influence on protective equipment development and standards testing. Finally, though the aim of this study was not to correlate location of strains within the brain with onset of concussive symptoms and duration, this study demonstrated that the concussive producing event can have an effect on location of peak strain and strain field within regions of the cerebrum associated with concussive symptoms.