Janie Cournoyer1, T Blaine Hoshizaki2. 1. Human Kinetics, University of Ottawa, Ottawa, Canada. Electronic address: jcour016@uottawa.ca. 2. Human Kinetics, University of Ottawa, Ottawa, Canada.
Abstract
BACKGROUND: Loss of consciousness is a poorly understood indicator of concussion severity. Conflicting results have been published supporting loss of consciousness as a severe concussion as well as having no relationship with severity. Understanding how loss of consciousness relates to brain trauma severity will provide useful insights to guide rule changes and return to sport protocols. The purpose of this study was to compare magnitudes of head acceleration and brain tissue deformation for punches resulting in a loss of consciousness and punches that do not. METHODS: Physical representations of boxing punches presenting with and without loss of consciousness were performed using an anthropometric headform and finite element model. The variables measured were peak linear and rotational acceleration, maximum principal strain, cumulative strain damage 10%, and strain rate in five regions of the brain. FINDINGS: Loss of consciousness in boxing resulted from hooks to the side of the mandible creating high levels of rotational acceleration and increased magnitudes of brain trauma in all regions of the brain. Differences between punches resulting in loss of consciousness and no loss of consciousness were distinguished by maximum principal strain for each of the brain region analyzed. INTERPRETATION: This research supports the notion that loss of consciousness in boxing is caused by higher levels of brain trauma and may require a longer recovery time.
BACKGROUND:Loss of consciousness is a poorly understood indicator of concussion severity. Conflicting results have been published supporting loss of consciousness as a severe concussion as well as having no relationship with severity. Understanding how loss of consciousness relates to brain trauma severity will provide useful insights to guide rule changes and return to sport protocols. The purpose of this study was to compare magnitudes of head acceleration and brain tissue deformation for punches resulting in a loss of consciousness and punches that do not. METHODS: Physical representations of boxing punches presenting with and without loss of consciousness were performed using an anthropometric headform and finite element model. The variables measured were peak linear and rotational acceleration, maximum principal strain, cumulative strain damage 10%, and strain rate in five regions of the brain. FINDINGS:Loss of consciousness in boxing resulted from hooks to the side of the mandible creating high levels of rotational acceleration and increased magnitudes of brain trauma in all regions of the brain. Differences between punches resulting in loss of consciousness and no loss of consciousness were distinguished by maximum principal strain for each of the brain region analyzed. INTERPRETATION: This research supports the notion that loss of consciousness in boxing is caused by higher levels of brain trauma and may require a longer recovery time.