The cross-cultural adaptation, construct validity, and intra-rater reliability of the functional mobility scale in Brazilian Portuguese for children and adolescents with spina bifida

Purpose The purpose of this study was to perform a cross-cultural adaptation of the Functional Mobility Scale (FMS) to Brazilian Portuguese and analyse its construct validity and intra-rater reliability in a sample of caregivers of children and adolescents with spina bifida (SB). Material and methods The cross-cultural adaptation followed five stages: two forward translations, synthesis, back-translation, committee review and pre-testing (n = 20). Construct validity was assessed by comparing the FMS with the classifications of Hoffer and Schoenmakers (n = 40). Intra-rater reliability was assessed by comparing the ratings of 14 caregivers, on two occasions. Kendall's tau correlation coefficient was used to test the construct validity of the FMS, while the kappa coefficient was used to test intra-rater reliability. Results Caregivers reported no difficulties with completing the FMS in Brazilian Portuguese. Construct validity tests showed positive correlations between the distances of 5 m (house), 50 m (school) and 500 m (community) in the FMS and the classifications of Hoffer (tau = 0.84; tau = 0.90; tau = 0.68; p < 0.01) and Schoenmakers (tau = 0.83; tau = 0.89; tau = 0.76; p < 0.01), respectively. Excellent intra-rater reliability (kappa = 0.9-1.0) was found for all three distances in the FMS. Conclusions The FMS in Brazilian Portuguese showed acceptable intra-rater reliability and construct validity when used to measure the mobility level of patients with SB. We recommend its use in clinical practice and research.

Automated summary

The study aimed to perform a cross-cultural adaptation of the Functional Mobility Scale to Brazilian Portuguese and analyze its construct validity and intra-rater reliability in caregivers of children and adolescents with spina bifida. The results showed acceptable intra-rater reliability and construct validity of the FMS in measuring the mobility level of SB patients, recommending its use in clinical practice and research.