[1] Univ Hosp Akershus, Dept Neurol, N-1478 Lorenskog, Norway
[2] Haukeland Hosp, Dept Neurol, N-5021 Bergen, Norway
[3] Univ Gothenburg, Sahlgrens Univ Hosp, Inst Clin Neurosci, Gothenburg, Sweden
[4] Tampere Univ Hosp, Dept Neurol, Neuroimmunol Unit, Tampere, Finland
[5] Univ Tampere, Sch Med, FIN-33101 Tampere, Finland
[6] Univ Helsinki, Dept Neurol, FIN-00014 Helsinki, Finland
[7] Aarhus Univ Hosp, Aarhus Hosp, Dept Neurol, DK-8000 Aarhus, Denmark
[8] Univ Hosp N Norway, Dept Neurol, Tromso, Norway
[9] Lund Univ, Univ Hosp, Dept Neurol, S-22100 Lund, Sweden
[10] Copenhagen Univ Hosp, Rigshosp, Dept Neurol, Danish MS Res Ctr, Copenhagen, Denmark
[11] Univ Bergen, Neurol Sect, Dept Clin Med, N-5020 Bergen, Norway