1. Department of Rehabilitation Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
2. Department of Rehabilitation Medicine and, Department of Oral and Maxillofacial Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
3. Department of Rehabilitation Medicine Erasmus MC, Rijndam Rehabilitation Center Rotterdam, Rotterdam, The Netherlands
4. Center De Hoogstraat Revalidatie, Utrecht, The Netherlands