Interobserver reliability of the Turkish version of the expanded and revised gross motor function classification system

Purpose: Cerebral palsy (CP) is the most common disability in childhood. The gross motor function classification system (GMFCS) has become an important tool to assess motor function in CP patient. In 2007, the expanded and revised (E&R) version of GMFCS which includes age band for youth 12-18 years of age was developed. The aim of this study was to evaluate reliability of Turkish version of expanded and revised GMCS. Methods: We assessed interobserver reliability between two physical medicine and rehabilitation specialists in 136 children with CP and test-retest reliability within a subgroup of 48 patients. Percent agreement, intraclass correlation coefficient (ICC) and mu statistics were used to evaluate reliability. Result: The ICC between two physicians was 0.97 and the total agreement was 89%. This result indicates excellent agreement. The overall weighted mu was 0.86. High test-retest reliability was found (ICC: 0.94 95% confidence interval) and the total agreement was 75% for test-retest reliability. Conclusion: The Turkish version of the E&R GMFCS is shown to be reliable and valid for assessment of Turkish CP children.