[1] Royal Melbourne Hosp, Ctr Neurosci, Dept Neurol, Parkville, Vic 3050, Australia
[2] Univ Melbourne, Dept Neurol, Parkville, Vic 3052, Australia
[3] Univ Glasgow, Glasgow G12 8QQ, Lanark, Scotland
[4] Stanford Univ, Med Ctr, Stanford, CA 94305 USA
[5] Univ Essen Gesamthsch, D-4300 Essen 1, Germany
[6] Univ Toronto, Toronto, ON, Canada