[1] Kings Coll London, Sch Med, Dept Clin Neurosci, London WC2R 2LS, England
[2] Consultat Pathol Neuromusculaire Grp Hosp, Pitrie Saltpetriere, France
[3] Johns Hopkins Univ, Dept Neurol, Baltimore, MD 21218 USA
[4] London Hlth Sci, Div Neurol, London, ON, Canada
[5] Hosp Univ Sta Creu & St Pau, Serv Neurol, Barcelona, Spain
[6] Dept Neurol, Baltimore, MD USA
[7] Univ Milan, Dept Neurol, I-20122 Milan, Italy
[8] Univ Sydney, Dept Neurol, Sydney, NSW 2006, Australia
[9] Univ Wurzburg, Wurzburg, Germany
[10] Univ Amsterdam, Acad Med Ctr, NL-1012 WX Amsterdam, Netherlands