1. From Departments of Clinical Neurosciences (M.D.H., N.S., B.M., S.B., P.K., T.W., M.G., A.M.D.), Radiology (M.D.H., P.K., M.G., A.M.D.), Medicine (M.D.H.), and Community Health Sciences (M.D.H.), Foothills Hospital, University of Calgary, Calgary, Alberta, Canada; Department of Neurology (R.B.), All India Institute of Medical Sciences, New Delhi, India.