[1] Univ Dusseldorf, Dept Neurol, D-40225 Dusseldorf, Germany
[2] Univ Texas SW Med Ctr Dallas, Div Neurol, Med Serv, Dallas Vet Affairs Med Ctr, Dallas, TX 75390 USA
[3] Univ Texas SW Med Ctr Dallas, Dept Neurol, Dallas, TX 75390 USA
[4] Tech Univ Munich, Klinikum Rechts Isar, Dept Neurol, D-8000 Munich, Germany