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

ABSTRACT

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 $\kappa$=0.75–0.95 (video/observation). Test–retest reliability was $\kappa$=0.93–0.96. Concurrent validity (PMP) was $\rho$=−0.84-to–0.96. Convergent validity (PEDI-CAT) was $\rho$=−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.

KEYWORDS:

• Powered wheelchairs
• cerebral palsy
• tool use
• participation
• cognitive impairment

Acknowledgements

We would like to thank the staff and children/adolescents of the MESHI Rehabilitation Centre in Jerusalem for their cooperation and involvement in the development of the tool.

Declaration of interest

The authors report no conflict of interest.