Stability of the gross motor function classification system in children with cerebral palsy for two years

BACKGROUND: The prognosis of gross motor function is a major concern for therapy and intervention in children with cerebral palsy (CP). The classification system for gross motor function, the Gross Motor Function Classification System (GMFCS), is actively studied because it could be useful in the communication between professionals and families. This study aimed to verify the stability of GMFCS over 2 years in children with CP aged 2–12 years. METHODS: The GMFCS level of 100 children with CP who underwent rehabilitation therapy in hospitals or who attended special elementary schools in South Korea were collected in the study. The agreements across three measurement points were analyzed in these children. RESULTS: The weighted kappa coefficients were statistically significant (p < .05). The coefficients ranged from 0.690 to 0.789 in children with CP aged 2–12 years. The lowest coefficient of 0.557 was observed in children with CP aged 2–4 years between the first and third measurements points. CONCLUSIONS: The results provided evidence of GMFCS stability for the first year and change of the GMFCS during the two-year study period in children aged 2–4 years. Moreover, the findings indicate that the stability of GMFCS varies with time, duration, and age. It is recommended that GMFCS assessments be performed periodically, which are even more necessary for children with CP aged 2–4 years.