[1] Med Coll Wisconsin, Dept Neurosurg, Milwaukee, WI 53226 USA
[2] Med Coll Wisconsin, Dept Neurol, Milwaukee, WI 53226 USA
[3] Univ British Columbia, Dept Psychiat, Vancouver, BC, Canada
[4] Univ Missouri Kansas City, Psychol & Neurobehav Associates Inc, State Coll, PA USA
[5] Melbourne Brain Ctr, Florey Inst Neurosci & Mental Hlth, Melbourne, Vic, Australia
[6] Int Rugby Board, Sydney, NSW, Australia