1. Division of Neurological Pain Research and Therapy; Department of Neurology; University Hospital Schleswig-Holstein; Kiel Germany
2. StatConsult GmbH; Magdeburg Germany
3. Centre of Anaesthesiology, Intensive Care Medicine; Pain Medicine and Palliative Care Medicine; Benidictus Hospital Tutzing and Department of Anaesthesiology; Technical University of Munich; Munich Germany
4. Department of Neurology; Klinikum rechts der Isar; Technical University of Munich; Munich Germany