The Development and Evaluation of the Powered Mobility Function Scale (PMFS) for Children and Adolescents with Cerebral Palsy.

Aims: To describe the development and evaluation of a novel task-based measure of powered mobility function: the Powered Mobility Function Scale (PMFS).Methods: PMFS was developed in Hebrew in four phases, with feedback from clinicians and clients. Psychometric properties (inter-rater, test-retest reliability, concurrent, convergent and known-groups validity) were evaluated for N = 49 children and adolescents with Cerebral Palsy (11.1 ± 4.8y) using Powered Mobility Program (PMP), Gross Motor Function Classification System (GMFCS), Manual Ability Classification System (MACS) and Pediatric Evaluation of Disability Inventory Computer Adaptive Test (PEDI-CAT)Results: PMFS development involved 3 versions over three years. Inter-rater reliability was κ=0.75-0.95 (video/observation). Test-retest reliability was κ=0.93-0.96. Concurrent validity (PMP) was ρ=-0.84-to-0.96. Convergent validity (PEDI-CAT) was ρ=-0.47-to-0.70. Known-groups validity (GMFCS/MACS) demonstrated medium effect sizes (r = 0.33-0.46)Conclusions: PMFS is valid and reliable for measuring powered mobility function in children and adolescents with CP. Future validation of the English version of PMFS is warranted.