Development of the Brazilian version of the Performance of Upper Limb scale for children and adolescents with Duchenne muscular dystrophy

Abstract

Background: Duchenne muscular dystrophy (DMD) is one of the most common and disabling childhood genetic diseases. The course of DMD involves progressive muscular degeneration and weakness, leading to functional decline. The Performance of the Upper Limb scale (PUL) is a specific instrument designed to assess the upper limb function of patients with DMD.

Objective: To adapt the PUL cross-culturally to Brazilian Portuguese (PUL-Br) and assess the convergent validity, structural validity, inter-rater reliability, and internal consistency for Brazilian patients with DMD METHODS: The cross-cultural adaptation involved six steps: translation to Brazilian Portuguese, Brazilian Portuguese translation synthesis, back-translation to English, back-translation synthesis, an expert committee review, and a pre-final version test (n = 12). The convergent validity of the PUL-Br was evaluated by examining its correlation to the Motor Function Measure scale (MFM) using 30 patients with DMD. Confirmatory factor analysis was conducted to assess structural validity. Intraclass correlation coefficient (ICC) verified the PUL-Br interrater reliability. Cronbach's alpha was calculated to verify internal consistency.

Results: The PUL was cross-culturally adapted to Brazilian Portuguese. A strong and positive correlation was found between the PUL-Br total score and the total score on the MFM (r = 0.83; 95% CI: 0.67, 0.91). The PUL-Br showed a satisfactory fit of the data to the three-factor model, excellent inter-rater reliability (ICC: 0.94), and good internal consistency (Cronbach's: 0.91).

Conclusion: The PUL-Br is valid and reliable for assessing the upper limb function of Brazilian patients with DMD.

Keywords: Function; Neuromuscular diseases; Physical therapy; Rehabilitation; Scale; Upper limbs.