1. Faculty of Physical Education and Physiotherapy; Vrije Universiteit Brussel; Laarbeeklaan 103 Brussels 1090 Belgium
2. Department of Physiotherapy; UZ Brussel; Brussels Belgium
3. Department of Pediatrics; UZ Brussel, Vrije Universiteit Brussel; Brussels Belgium
4. Information Research Group; Department of Public Health, Biostatistics and Medical Informatics; Vrije Universiteit Brussel; Brussels Belgium