[1] VU Med Ctr, Amsterdam, Netherlands
[2] Univ Rochester, Med Ctr, Dept Neurol, Rochester, NY 14642 USA
[3] Univ Basel Hosp, CH-4031 Basel, Switzerland
[4] Mt Sinai Sch Med, New York, NY USA
[5] St Michaels Hosp, Div Neurol, Toronto, ON M5B 1W8, Canada
[6] Cleveland Clin Fdn, Mellen Ctr Multiple Sclerosis Treatment & Res, Cleveland, OH 44195 USA
[7] Biogen Idec Inc, Cambridge, England