1. German Paediatric Pain Centre, Children's and Adolescents' Hospital Datteln, Datteln, Germany
2. Department of Children's Pain Therapy and Paediatric Palliative Care, Witten/Herdecke University, Faculty of Health, School of Medicine, Witten, Germany
3. Clinical Psychology and Psychological Interventions, Institute for Psychology, University of Duisburg-Essen, Essen, Germany
4. PedScience Research Institute, Datteln, Germany