Reliability and validity of pediatric powered mobility outcome measures

Purpose: To determine the intra-rater and inter-rater reliability of the Powered Mobility Program (PMP) and the Israel Ministry of Health Powered Mobility Proficiency Test (PM-PT); to test inter-rater reliability of the Assessment of Learning Powered Mobility (ALP) tool; to determine the convergent validity of these measures for children with physical disabilities. Materials and methods: Participants included 30 children (mean 10 years, 6 months [SD 3 years, 7 months]; range: 6–18 years) with cerebral palsy and other neuromuscular disorders. Participants were non-proficient powered wheelchair drivers. Two blinded raters assessed the driving ability by viewing videos of the participants twice as they drove a pre-designed route at ALYN Hospital, Israel. They were assessed via the PMP, ALP and PM-PT outcome measures. Intra-class correlation coefficients (ICC_2,1) were used to test intra-rater and inter-rater reliability and Spearman correlation coefficients were used to assess convergent validity. Results: The PMP intra-rater reliability revealed ICCs_2,1 of coefficients were 0.97/0.98 for both raters. For the PM-PT the ICC_2,1 was 0.89/0.96 for both raters. The PMP inter-rater reliability ICC_2,1 was 0.94/0.87 for the two tests, for the PM-PT the ICC_2,1 was 0.91/0.87 for the two tests and for the ALP the ICC_2,1 was 0.83. The convergent validity between the PMP and the PM-PT was r _s=0.96, between the PMP and ALP was r _s=0.89 and between the PM-PT and ALP was r _s=0.87. Conclusions: The PMP and PM-PT intra and interrater reliability were good to excellent, the ALP inter-rater reliability was good and the convergent validity between all three measures was good to excellent.Implications for rehabilitation There is evidence of validity and reliability for three tests of powered wheelchair proficiency (PMP, PM-PT and ALP). Children using powered mobility, aged 6–18 years, now have outcome measures with empirical evidence that was previously lacking. When time for assessment is limited, the shorter PM-PT can be used instead of the more comprehensive PMP.