Aims: To create longitudinal trajectories and reference percentiles for performance in self-care of children with cerebral palsy (CP).Methods: Participants were 708 children with CP, 18 months through 11 years of age and their parents residing in 10 regions across Canada and the United States. Gross Motor Function Classification System (GMFCS) levels were determined by consensus between parents and therapists. Parents' completed the Performance in Self-Care domain of the Child Engagement in Daily Life Measure two to five times at 6-month intervals. Nonlinear mixed-effects models were used to create longitudinal trajectories. Quantile regression was used to construct cross-sectional reference percentiles.Results: The trajectories for children in levels I, II, and III are characterized by an average maximum score between 79.6 (level I) and 62.8 (level III) and an average attainment of 90% of the maximum score between 7 and 9 years of age. The trajectories for children in level IV and V show minimal change over time. Extreme variation in performance among children of the same age and GMFCS level complicate interpretation of percentile change of individual children.Conclusion: The findings are useful for monitoring self-care of children with CP and evaluating change for children in GMFCS levels I-III.
