1. From the Departments of Neurology (A.J.G., F.B., C.S.-W., S.H., T.B., R.W., W.H.), Neuroradiology (M.F.), and Medicine (W.F., C.B., P.-P.N.), University of Heidelberg; Department of Medicine, University of Marburg (R.S.); and Department of Epidemiology, German Cancer Research Center, Heidelberg (H.B.), FRG.