Gross Motor Function Classification System Expanded & Revised (GMFCS E & R): reliability between therapists and parents in Brazil

ABSTRACT

BACKGROUND: Several studies have demonstrated the importance of using the Gross Motor Function Classification System (GMFCS) to classify gross motor function in children with cerebral palsy, but the reliability of the expanded and revised version has not been examined in Brazil (GMFCS E & R). OBJECTIVE: To determine the intra- and inter-rater reliability of the Portuguese-Brazil version of the GMFCS E & R applied by therapists and compare to classification provided by parents of children with cerebral palsy. METHOD: Data were obtained from 90 children with cerebral palsy, aged 4 to 18 years old, attending the neurology or rehabilitation service of a Brazilian hospital. Therapists classified the children's motor function using the GMFCS E & R and parents used the Brazilian Portuguese version of the GMFCS Family Report Questionnaire. Intra- and inter-rater reliability was obtained through percentage agreement and Cohen's unweighted Kappa statistics (k). The Chi-square test was used to identify significant differences in the classification of parents and therapists. RESULTS: Almost perfect agreement was reached between the therapists [K=0.90 (95% confidence interval 0.83-0.97)] and intra-raters (therapists) with K=1.00 [95% confidence interval (1.00-1.00)], p<0.001. Agreement between therapists and parents was substantial (k=0.716, confidence interval 0.596-0.836), though parents classify gross motor impairment more severely than therapists (p=0.04). CONCLUSIONS: The Portuguese version of the GMFCS E & R is reliable for use by parents and therapists. Parents tend to classify their children's limitations more severely, because they know their performance in different environments. .