1. Division of Neurological Pain Research and -therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
2. Katholisches Marienkrankenhaus, Department. Of Neurology, Hamburg, Germany
3. Asklepios Klinik Nord, Center of Interdisciplinary Pain Therapy, Hamburg, Germany
4. Institute of Medical Informatics and Statistics, University Hospital Schleswig-Holstein, Kiel, Germany
5. Klinikum Saarbrücken, Department. Of Neurology