1. From the Departments of Neurology (A.Slowik, A.B., J.P., T.D., A.Szczudlik) and Neurosurgery (M.B., T.K., R.C.), Jagiellonian University, Medical College, Krakow, Poland; and the Department of Neurology (D.A.F.), University of Michigan, Ann Arbor, Mich.