Marie Holmefur

Aim To describe the development of the use of the affected hand in bimanual tasks in children with unilateral cerebral palsy (CP) from 18 months to 18 years. Specifically, whether early development can be confirmed in a larger cohort and how development progresses during adolescence. Method In total, 171 participants (95 males, 76 females; mean age 3 years 1 month [SD 3 years 8 months], range 18 months–16 years at inclusion) were classified in Manual Ability Classification System (MACS) levels I ( n = 41), II ( n = 91), and III ( n = 39). Children were assessed repeatedly (median 7, range 2–16 times) with the Assisting Hand Assessment: in total 1197 assessments. Developmental trajectories were estimated using a nonlinear mixed effects model. To further analyse the adolescent period, a linear mixed model was applied. Results The developmental trajectories were different between participants in MACS levels (MACS I–II, II–III) in both rate (0.019, 95% confidence interval [CI] 0.006–0.031, p = 0.034; 0.025, 95% CI 0.015–0.037, p < 0.001) and limit (19.9, 95% CI 16.6–23.3, p = 0.001; 7.2, 95% CI 3.3–11.2, p < 0.003). The individual variations were large within each level. The developmental trajectories were stable over time for all MACS levels between 7 and 18 years ( p > 0.05). Interpretation Children and adolescents with unilateral CP have considerable development at an early age and a stable ability to use their affected hand in bimanual activities from 7 to 18 years in all MACS levels.