1. Department of Neurosciences in Children, Norwegian Quality and Surveillance Registry for Cerebral Palsy (NorCP), Oslo University Hospital, Oslo, Norway
2. Centre for Biostatistics and Epidemiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
3. Research Centre for Habilitation and Rehabilitation Models and Services (CHARM), Institute of Health and Society, University of Oslo, Oslo, Norway
4. Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden