Intra-Rater and Inter-Rater Reliability of the 10-Point Manual Muscle Test (MMT) of Strength in Children with Juvenile Idiopathic Inflammatory Myopathies (JIIM)

Objective. Children with juvenile idiopathic inflammatory myopathies (JIIM) present with muscle inflammation and decreased strength that may affect their functional abilities. The purpose of this study was to determine the intra-rater and inter-rater reliability of the 0 to10-point manual muscle testing method for children with JIIM.Methods. For the intra-rater and inter-rater reliability studies, 10 and 9 children with JIIM participated, respectively. For intra-rater reliability, one pediatric therapist completed two assessments in one day with a one-hour break. For inter-rater reliability, four therapists assessed the same child within a single morning.Results. Spearman correlations for intra-rater reliability ranged from 0.70 to 1.00. Kendall's W coefficient for inter-rater reliability of groups of muscles (total, proximal, distal, and peripheral) ranged from 0.51 to 0.76.Conclusions. The total, proximal, and peripheral Manual Muscle Test (MMT) score, using the 0-10 point scale, has acceptable reliabil...