1. From the Department of Neuromuscular Medicine and Peripheral Nerve Laboratory (A.G., T.R., D.D., J.M., M.L.M., S.E.B., P.J.B.D., C.J.K.), Mayo Clinic, Rochester, MN; The Canberra Hospital (R.L.), Garran, Australia; and Department of Neurosurgery (R.J.S.), Mayo Clinic Foundation, Rochester, MN.