1. Danish Pain Research Center Aarhus University Aarhus Denmark
2. Pain Management Research Unit Department of Anesthesiology Faculty of Medicine King Chulalongkorn Memorial Hospital Chulalongkorn University Bangkok Thailand
3. Department of Public Health Aarhus University Aarhus Denmark
4. Department of Medicine Faculty of Medicine King Chulalongkorn Memorial Hospital Chulalongkorn University Bangkok Thailand
5. Department of Neurology Aarhus University Hospital Aarhus Denmark