1. Department of Medical, Clinical and Experimental Psychology, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands
2. Pain Management and Research Center, University Hospital Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands
3. Department of Medical Psychology, University Hospital Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands
4. Rehabilitation Center "Hoensbroeck", PO Box 88, 6430 AB Hoensbroek, The Netherlands
5. Department of Educational Sciences, Katholieke Universiteit Leuven, Vesaliusstraat 2, 3000 Leuven, Belgium
6. Department of Physical Therapy, University Hospital Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands