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

Abstract

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 (τ = 0.84; τ = 0.90; τ = 0.68; p < 0.01) and Schoenmakers (τ = 0.83; τ = 0.89; τ = 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.

Implications for Rehabilitation

• A valid and reliable instrument for assessing the mobility of patients with SB;

• A cross-cultural and adapted FMS in Brazilian Portuguese;

• An instrument for therapeutic and functional approaches outside the clinical

• setting;

• The FMS in the Brazilian Portuguese online version shows mistranslations.

Keywords:

• Spina bifida
• functional mobility scale
• cross-cultural adaptation
• validity
• reliability

Acknowledgements

The authors thank the volunteers who participated in this study and their caregivers as well as Dra. Carla Andrea Cardoso Tanuri Caldas from the Rehabilitation Centre of the Clinical Hospital, for the excellent assistance. The authors are very grateful to the Hugh Williamson Gait Laboratory and the Royal Children's Hospital to provide us the use of FMS. The authors also like to thank FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo; Process number: 2017/23746-9 and 2017/17596-4) and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior). Profa. Dra. Ana Claudia Mattiello-Sverzut is a research recipient of the CNPq (Process: 309058/2018-0)

Disclosure statement

The authors have no conflicts of interest to disclose.

Additional information

Funding

This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo [grant numbers 2017/23746-9 and 2017/17596-4].