Reproducibility of Muscle Strength Testing for Children with Spina Bifida

Aims: Examine the inter-rater reliability of the Daniels and Worthingham (D&W) manual muscle test (MMT) protocol for children with spina bifida between experienced and novice physiotherapists.

Methods: Thirteen children with spina bifida (two males) aged 6 to 18 years were recruited from a spina bifida service in a state-wide tertiary children's hospital. Each child had the muscle strength of 19, and lower limb muscles were measured bilaterally by one experienced and one novice physiotherapist using the D&W MMT protocol. Examiner and limb order were counterbalanced. Standard training and recording sheets were used. Agreement between raters was examined with quadratic weighted kappa (κ), percentage exact agreement (%EA), and the Bland-Altmann Limits of Agreement (LoA). Minimal detectable change (MDC) was calculated.

Results: Inter-rater agreement between the experienced and novice raters was excellent (κ = 0.95; 95% confidence interval: 0.94-0.96); %EA was good (72.3%); and clinically appropriate LoA levels were -1.30-1.40. The MDC was 1.11 points on a six-point MMT scale.

Conclusions: The D&W MMT protocol, when used after standard training and with standard recording sheets, was reproducible for children with spina bifida, aged 6-18 years.