[1] Royal Coll Physicians, London NW1 4LE, England
[2] Univ Cambridge, Cambridge, England
[3] CHU Rennes, Rennes, France
[4] Univ Calif San Francisco, San Francisco, CA 94143 USA
[5] Karl Franzens Univ Graz, Graz, Austria
[6] Mt Sinai Sch Med, New York, NY USA
[7] Natl Inst Neurol Disorders & Stroke, Bethesda, MD USA
[8] Univ British Columbia, Vancouver, BC V5Z 1M9, Canada
[9] Free Univ Amsterdam, NL-1081 HV Amsterdam, Netherlands
[10] Natl Multiple Sclerosis Soc, New York, NY USA
[11] Univ Lund Hosp, S-22185 Lund, Sweden
[12] UCL, Inst Neurol, London, England
[13] Univ Arizona, Hlth Sci Ctr, Tucson, AZ USA
[14] Neurol Inst, London, England
[15] Univ Calif Irvine, Irvine, CA USA
[16] Mayo Clin & Mayo Fdn, Rochester, MN 55905 USA
[17] Univ Texas, Hlth Sci Ctr, Houston, TX USA