1. From the Department of Medicine (Neurology) (M.C.F.S.), University of Ottawa, Canada
2. Ottawa Hospital Research Institute (M.C.F.S., B.D., S.C., C.-Q.W.), University of Ottawa, Canada
3. Department of Community Health Sciences (S.P.), University of Calgary, Canada.
4. Departments of Radiology and Clinical Neurosciences (M.G.), University of Calgary, Canada.
5. Department of Clinical Neurosciences (A.M.D.), University of Calgary, Canada.
6. Department of Clinical Neurosciences and Community Health Sciences (M.D.H.), University of Calgary, Canada.