Determinants of gross motor function of young children with cerebral palsy: a prospective cohort study

AIM: The aim of this study was to test a model of determinants of gross motor function of young children with cerebral palsy (CP). METHOD: Four hundred and twenty-nine children with CP (242 males, 187 females; mean age 3 y 2 mo, SD 11 mo) representing all levels of the Gross Motor Function Classification System (GMFCS) participated. Children in levels I to II and III to V were classified as Groups 1 and 2 respectively. Distribution of CP was quadriplegia, 44%; hemiplegia, 24%; diplegia, 23%; triplegia, 6%; and monoplegia, 2% (data not available for 1%). Impairment and motor function data were collected by reliable assessors; parents completed questionnaires on health conditions and adaptive behavior. Seven months later, parents were interviewed about family life and services received. One year after the study onset, motor function was re-evaluated. Analysis involved structural equation modeling. RESULTS: The well-fitting model explained 58% and 75% of the variance in motor function at study completion for Groups 1 and 2 respectively. Primary impairments (spasticity, quality of movement, postural stability, and distribution of involvement; β=0.52-0.68) and secondary impairments (strength, range of motion limitations, and reduced endurance; β=0.25-0.26) explained the most variance. Adaptive behavior was a significant determinant only for Group 2 (β=0.21) and participation in community programs was significant only in Group 1 (β=0.13). INTERPRETATION: Motor function is supported by optimizing body structures and function for all children and enhancing adaptive behavior for children with greater motor challenges.