1. Division of Neurosurgery, University of Toronto and Toronto Western Hospital, Toronto, Ontario, Canada.
2. Canadian Concussion Center, Toronto Western Hospital, Toronto, Canada.
3. Division of Neurology, University of Toronto and Toronto Western Hospital, Toronto, Ontario, Canada.
4. Division of Neuroradiology, University of Toronto and Toronto Western Hospital, Toronto, Ontario, Canada.
5. Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.