[1] Univ Munich, Dept Neurol, D-80539 Munich, Germany
[2] Katholieke Univ Leuven, Dept Neurol, B-3001 Leuven, Belgium
[3] Inst Psychiat, Dept Clin Neurosci, London, England
[4] Univ London Kings Coll, Sch Med & Dent, London, England
[5] Univ Amsterdam, Acad Med Ctr, Lab Expt Neurol, NL-1105 AZ Amsterdam, Netherlands
[6] Univ Angers, Med Ctr, Dept Neurol B, Angers, France
[7] Univ Bonn, Dept Neurol, D-5300 Bonn, Germany
[8] Charing Cross Hosp, Neuromuscular Unit, London, England
[9] Univ Milan, IRCCS, Osped Maggiore, Dept Neurol, I-20122 Milan, Italy
[10] Univ Utrecht, Div Neuromuscular Dis, NL-3508 TC Utrecht, Netherlands
[11] Cephalon Inc, W Chester, PA USA