1. Department of Rehabilitation Medicine, Adelante Centre of Expertise in Rehabilitation and Audiology, zandbergsweg 111, 6432 CC, Hoensbroek, The Netherlands
2. Department of Rehabilitation Medicine, Care and Public Health Research Institute, Maastricht University, Universiteitssingel 40, 6229 ER, Postal Box 616, 6200 Maastricht, The Netherlands
3. Discipline of Biomedical Science, School of Medical Sciences, Sydney University, Sydney, Australia
4. Department of Epidemiology, Musculoskeletal Group, Care And Public Health Research Institute, Maastricht University, Universiteitssingel 40, 6229 ER, Postal Box 616, 6200 Maastricht, The Netherlands
5. Department of Rehabilitation Medicine, Libra Rehabilitation and Audiology, Vogelsbleek 1 ingang Land van Horne, 6001 BE, Weert, The Netherlands