1. Canadian Concussion Centre, Division of Neurosurgery, Toronto Western Hospital and University of Toronto, Toronto, Ontario, Canada.
2. Canadian Concussion Centre, Toronto Western Hospital and University of Toronto, Toronto, Ontario, Canada.
3. Biostatistics Research Unit, University Health Network, Toronto, Ontario, Canada.
4. Canadian Concussion Centre, Division of Neurology, Toronto Western Hospital and University of Toronto, Toronto, Ontario, Canada.