1. From the Department of Neuroscience (M.P.), University of Perugia, Perugia, Italy; The John P. Robarts Research Institute (M.P., M.E., B.L.S., H.M., H.J.M.B.) and the Departments of Epidemiology and Biostatistics (M.E.) and Clinical Neurological Sciences (M.E., H.J.M.B.), University of Western Ontario, London, Ontario, Canada; the Department of Neurology (L.J.K.), University Medical Centre, Utrecht, the Netherlands; and the Department of Neurology (S.C.), Wayne State University, Detroit, Mich.