The validity and reliability of the Turkish version of the functional mobility scale in patients with cerebral palsy

Objectives: The aim of this study was to investigate the validity and reliability of the Turkish version of the Functional Mobility Scale (FMS) in patients with cerebral palsy. Patients and methods: The validity and reliability study was conducted with 100 cerebral palsy patients (66 males, 34 females; mean age: 6.4±2.7 years; range, 2 to 18 years) between July 2015 and July 2018. The translation of the FMS was performed according to international standards. For test-retest reliability, 54 patients were reevaluated one week after the initial test with the Turkish version of the FMS, and Cohen's weighted kappa values were analyzed. The validity of the scale was assessed by correlating the FMS with the Gross Motor Function Classification System and the Gillette Functional Assessment Questionnaire Walking Scale. Twenty patients were evaluated by two researchers for interobserver reliability. Results: The kappa coefficients for test-retest reliability were 0.90 for FMS 5 m, 0.92 for FMS 50 m, and 0.91 for FMS 500 m. An evaluation of the validity revealed a significant correlation between FMS and the Gross Motor Function Classification System for all distances (r=-0.95, r=-0.96, and r=-0.92 for 5, 50, and 500 m, respectively; p <0.001), as well as the Gillette Functional Assessment Questionnaire Walking Scale (r=-0.95, r=-0.94, and r=-0.91 for 5, 50, and 500 meters, respectively; p <0.001). The kappa coefficients related to interobserver reliability were 0.73 for 5 m, 0.69 for FMS 50 m, and 0.81 for FMS 500 m. Conclusion: The Turkish version of the FMS can be considered a valid and reliable instrument for the assessment of cerebral palsy patients.