1 CHEO Research Institute, Ottawa, Ontario, Canada (Drs Dawson and Zemek); Montfort Hospital Institut du Savoir, University of Ottawa, Ottawa, Ontario, Canada (Dr Johnston); The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada (Drs Marshall and Lithopoulos); Keenan Research Centre, St Michael's Hospital, Unity Health Toronto and Faculty of Medicine (Neurosurgery) (Dr Schweizer), University of Toronto (Dr Reed), Toronto, Ontario, Canada; University of Kansas Medical Center, Kansas City (Dr Devos); and UGA Concussion Research Laboratory, Department of Kinesiology, University of Georgia, Athens (Dr Schmidt).