Clinical evaluator reliability for quantitative and manual muscle testing measures of strength in children

TLDR

Muscle strength in Duchenne muscular dystrophy trials has relied on manual muscle testing, but its high intra‑ and inter‑rater variability compromises study results. The study compared the reliability of 12 clinical evaluators performing manual muscle testing and quantitative muscle testing on 12 children with muscular dystrophy. Evaluators and subjects received brief training, and the study assessed inter‑rater reliability using both MMT and QMT. Quantitative muscle testing achieved ICCs >0.9 for biceps and grip and >0.8 for quadriceps, whereas manual muscle testing required repeated training to reach ICCs >0.75 for multiple joints, leading the authors to conclude QMT is more reliable and easier to implement, making it a superior strength measure for pediatric neuromuscular multicenter trials. © 2001 John Wiley & Sons, Inc., Muscle Nerve 24: 787–793.

Abstract

Abstract Measurements of muscle strength in clinical trials of Duchenne muscular dystrophy have relied heavily on manual muscle testing (MMT). The high level of intra‐ and interrater variability of MMT compromises clinical study results. We compared the reliability of 12 clinical evaluators in performing MMT and quantitative muscle testing (QMT) on 12 children with muscular dystrophy. QMT was reliable, with an interclass correlation coefficient (ICC) of >0.9 for biceps and grip strength, and >0.8 for quadriceps strength. Training of both subjects and evaluators was easily accomplished. MMT was not as reliable, and required repeated training of evaluators to bring all groups to an ICC >0.75 for shoulder abduction, elbow and hip flexion, knee extension, and ankle dorsiflexion. We conclude that QMT shows greater reliability and is easier to implement than MMT. Consequently, QMT will be a superior measure of strength for use in pediatric, neuromuscular, multicenter clinical trials. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 787–793, 2001.