[1] Univ Zurich, Dept Neurol, CH-8091 Zurich, Switzerland
[2] Univ Mannheim, Dept Neurol, Mannheim, Germany
[3] Univ Heidelberg, Dept Neurol, Heidelberg, Germany
[4] Univ Basel, Dept Neurol, Basel, Switzerland
[5] Univ Geneva, Dept Neurol, Geneva, Switzerland
[6] Univ Bern, Dept Neurol, Bern, Switzerland
[7] Univ Dusseldorf, Dept Neurol, D-4000 Dusseldorf, Germany