[1] Univ Giessen, Dept Neurol, Giessen, Germany
[2] John Radcliffe Hosp, Nuffield Dept Clin Neurosci, Oxford OX3 9DU, England
[3] Nordwestkrankenhaus, Dept Neurol, Frankfurt, Germany
[4] Kreiskrankenhaus Gummersbach, Dept Neurol, Gummersbach, Germany