Intra- and Interrater Reliability of the Spanish Version of the Gross Motor Function Measure (GMFM-SP-88).

Abstract

To assess intra- and interrater reliability of the Spanish version of the 88-item Gross Motor Function Measure (GMFM-SP-88), and its correlation to age and severity of children with cerebral palsy. Six raters assessed 50 videotapes and 4 viewed 50 recordings to determine intra- and interrater reliability, respectively. Intraclass correlation coefficients (ICCs), standard error of measurement (SEm), smallest real difference (SRD), and limits of agreement (LoA) were calculated. Intra- and interrater reliability were excellent for both total (ICC2,1 = 1.00, 95% confidence interval [CI] 0.99-1.00) and dimension scores (ICC2,1 = 0.99, 95% CI 0.99-1.00). The SEm and the SRD for the total score were acceptable (1.60 and 3.14, respectively). The average differences in dimension scores were below 1 and 0.1 points (95% LoA: -1.65 to 1.94, -1.06 to 0.86 for intra- and interrater reliability, respectively). The results support the potential use of the GMFM-SP-88 as a reliable tool, having correlation with age and severity. The GMFM-SP-88 is a reliable outcome measure to assess gross motor function in cerebral palsy. The GMFM-SP is the only tool available in Spanish to assess gross motor function in children and adolescents with cerebral palsy. The GMFM-SP-88 is a valuable resource for both Spanish physical therapists and researchers.