1. Department of Medical Psychology and Medical Sociology , Faculty of Medicine, Ruhr University Bochum , Bochum , Germany
2. Department of Kinesiology , University of Wisconsin–Madison , Madison , WI , USA
3. Pain Research Group, Pain Center, Department of Anesthesiology and Intensive Care Medicine , University Hospital Odense , Odense , Denmark
4. Department of Clinical Research , Faculty of Health Sciences, University of Southern Denmark , Odense , Denmark