1. Department of Clinical and Molecular Medicine Norwegian University of Science and Technology Trondheim Norway
2. Department of Neuromedicine and Movement Science Norwegian University of Science and Technology Trondheim Norway
3. Clinical Medicine Research Unit Oulu University Hospital and University of Oulu Oulu Finland
4. Public Health Unit, Finnish Institute for Health and Welfare Helsinki Finland
5. Helsinki University Eye and Ear Hospital Helsinki Finland
6. Department of Pediatrics Haukeland University Hospital Bergen Norway
7. Department of Clinical Science University of Bergen Bergen Norway
8. Children's Hospital, Helsinki University Hospital and University of Helsinki Helsinki Finland
9. Department of Rehabilitation Science and Health Technology Oslo Metropolitan University Oslo Norway
10. Children's Clinic, St. Olavs Hospital Trondheim University Hospital Trondheim Norway