1. Health Care Center for Pain Medicine and Mental Health; Saarbrücken Germany
2. BG University Hospital Bergmannsheil GmbH, Ruhr University Bochum; Department of Pain Medicine; Cample-de-la Bürk Platz 1 Bochum Germany 44789
3. University of Oxford; Pain Research and Nuffield Department of Clinical Neurosciences (Nuffield Division of Anaesthetics); Pain Research Unit Churchill Hospital Oxford Oxfordshire UK OX3 7LE
4. Technische Universität München; Department of Psychosomatic Medicine and Psychotherapy; Langerstr. 3 München Germany D-81675