1. From the Department of Neurology (T.J.I.), Mayo Clinic Scottsdale, Ariz; the Division of Biostatistics (W.M.O., T.J.H.C.), Mayo Clinic Rochester, Minn; the National Board of Health and Welfare (K.A.), Stockholm, Sweden; the Department of Emergency Medicine (L.R.G.), New York University School of Medicine, New York; the Department of Biostatistics (V.S.H.), Emory University, Atlanta, Ga; and the Department of Biostatistics (T.A.L.), Johns Hopkins Bloomberg School of Public Health, Baltimore, Md.