1. Department of Clinical Neurophysiology, University of Göttingen, Göttingen, Germany
2. Department of Clinical Neurophysiology and Sleepcenter. MCHaaglanden, Westeinde Hospital, The Hague, The Netherlands
3. Department of Neurology, Philipps University of Marburg, Germany
4. Paracelsus Elena Klinik, Centre of Parkinsonism and Movement Disorders, Kassel, Germany
5. Sleepcenter and Department of Clinical Neurophysiology, SEIN Zwolle, Zwolle, The Netherlands