[1] Univ Alberta, Div Neurol, Edmonton, AB, Canada
[2] Univ Alberta, Dept Diagnost Imaging, Edmonton, AB, Canada
[3] Univ Alberta, Div Neurosurg, Edmonton, AB, Canada
[4] Univ Calgary, Dept Clin Neurosci, Calgary, AB, Canada
[5] Univ Ottawa, Div Neurol, Ottawa, ON, Canada
[6] Univ British Columbia, Div Neurol, Vancouver, BC V5Z 1M9, Canada