Knowledge on long-term development can guide expectations of young individuals with cerebral palsy (CP) and their parents and inform treatment decisions. In children with CP, development of motor capacity has been described using development curves. The present study adds to this knowledge by describing development curves of motor and daily activity performance from childhood into adulthood of individuals with CP by functional severity level.

Individuals with CP (n=421) aged 1–20 years, with GMFCS I-V, 27% with intellectual disability (ID) were included. Participants were assessed up to four times at 1- or 2-year intervals and at a 13-year follow-up (n=122). Gross and fine motor performance and personal, domestic and community daily activity performance were assessed using the Vineland Adaptive Behavior Scales. Non-linear mixed effects analyses were used to describe development curves, characterized by a limit (average maximum score) and age₉₀ (age reaching 90% of the limit).

Limits of gross and fine motor performance decreased significantly (P<0.05) with each lower functional level. Children with GMFCS or MACS I-III reached age₉₀s of gross and fine motor performance around 6–8 years. Individuals with lower functional levels reached age₉₀s earlier (around 1–3 years). Individuals with GMFCS I-III without ID reach similar limits of daily activity performance. Their age₉₀s for daily activity performance were around 11–14 years (personal), 26–32 years (domestic) and 22–26 years (community). Individuals with ID reached lower daily activity performance limits and approached their limits earlier.

Children with CP approach motor performance limits between 6–8 years. Individuals with GMFCS I-III without ID develop performance of daily activities into adolescence and adulthood. Severely functionally affected individuals have the least favourable development of motor performance and those with ID of daily activity performance. Because of ongoing development of daily activities, we recommend routine monitoring of individuals with CP for activity limitations into adulthood.