1. Department of Neurology, Ayer Neuroscience Institute, Hartford Hospital, CT (S.D.A.).
2. Department of Neurology, Massachusetts General Hospital, Boston (M.N., J.Y.R., E.C.F., S.B.S.).
3. Department of Neurosurgery, Massachusetts General Hospital, Boston (R.W.R., J.E.V., J.D.R.).