1. From the Departments of Neurology and Neurological Sciences (G.W.A.), Stanford University School of Medicine, Calif; Food and Drug Administration (B.D.), Silver Spring, Md; the Department of Neurology (K.C.J.), University of Virginia School of Medicine, Charlottesville; the Department of Neurology (J.L.S.), Geffen School of Medicine, UCLA, Los Angeles, Calif; and the Department of Neurology (M.F.), University of Massachusetts School Medical School, Worcester.