1. Department of Sleep Medicine and Neuromuscular Disorders, University Hospital Muenster, Muenster, Germany
2. Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
3. Central Institute for Blood-Transfusion and Immunology, Medical University of Innsbruck, Innsbruck, Austria
4. Department of Neurology, Clinic Maria Frieden Telgte, Telgte, Germany and University of Göttingen, Göttingen, Germany
5. Hephata-Klinik Schwalmstadt-Treysa, Schwalmstadt- Treysa, Germany and Philipps University Marburg, Department of Neurology, Marburg, Germany