Karl Zimmerman, Janie Cournoyer, Helen Lai, Samuel B. Snider, David Fischer, Simon Kemp, Clara Karton, T. Blaine Hoshizaki, Mazdak Ghajari, David Sharp
Brain, 2022
Brain modelling · Past project
Biomechanical signature of loss of consciousness
Brain biomechanical modelling of sports collisions explains loss of consciousness.
Using an anatomically detailed finite element brain model and head kinematics from reconstructed American football collisions, we found that players who lost consciousness showed disproportionately large strain rate in brainstem nuclei responsible for arousal and awareness, providing a biomechanical signature for loss of consciousness.
Loss of consciousness is seen after head impacts in sports and other situations such as road traffic collisions and ejections. However, it is unclear why a head impact can lead to loss of consciousness.
We used our anatomically detailed finite element model of the human brain to predict the distribution of brain strain and strain rate during sports collisions that led to loss of consciousness, as well as those that did not. The head kinematics data were provided by colleagues at the University of Ottawa, who estimated head kinematics through reconstruction of American football collisions.
We found large strain and strain rate across the brain for players who lost consciousness. We also found that strain rate was disproportionately larger in brainstem nuclei responsible for arousal and awareness functions, providing a biomechanical signature for loss of consciousness.
These findings have been a factor in updating World Rugby’s return-to-play guidelines. In addition, this study has informed the development of a new standard for aircrew helmets, designed to assess helmets’ ability to reduce the risk of loss of consciousness.
Related publications