Gross motor function classification system - Preliminary study for Japanese children

Objective: The purpose of the study was to produce a version of the Gross Motor Function Classification System with the same construct as the original one that would be applicable to Japanese children with cerebral palsy. Design: The reliability studies were performed twice with a convenience sample (first study, 76 children with cerebral palsy; second study, 225 children with cerebral palsy). The first version of the translated Gross Motor Function Classification System was used in the first reliability study. It was revised based on the findings of the study and used in the second reliability study. Two examiners classified each child's level of gross motor function independently. We calculated kappas for individual levels and across, all levels to study interrater reliability. Results: The individual kappa for level V changed from 0.59 in the first reliability study to 0.87 in the second reliability study, whereas the overall kappa changed from 0.64 to 0.66. In the second reliability study, the factors that seemed to affect the reproducibility were the unfamiliar words used in the system, partial agreement of the children's status, and thinking of future levels. Conclusions: Explanation of words and a note stressing the importance of the introduction part should be added to the system for Japanese clinicians.