1. From the Division of Neurology, Department of Medicine (T.J.), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; the Department of Neurology, School of Medicine (P.A.W., S.S.), the Department of Biostatistics (A.B., J.M.), School of Public Health, and the Department of Mathematics and Statistics (R.B.D.), Boston University, Boston, Mass; and the Department of Neurology and Center for Neuroscience (C.D.), University of California-Davis, Sacramento, Calif.