Inter-Rater Reliability of the Modified Ashworth Scale of Spasticity

This study was performed to determine the inter-rater reliability of manual tests of elbow, knee flexor, and ankle dorsiflexor muscle spasticity graded on the Modified Ashworth Scale. Two raters each independently graded the spasticity of 32 patients with intracranial lesions after moving the paretic limb passively through the available range of motion. The patients were asked to simultaneously squeeze therapeutic putty with their non-paretic hand for reinforcement. The ratings were compared by the Wilcoxon matched pairs signed-rank test and by the Kendall's coefficient of rank(tau) correlation. There was singificant correlation between two raters for spasticity at the elbow, knee flexor, and ankle dorsiflexor. The correlations of the two raters ranged from .6746 to .9308. The highest correlation was for the elbow with reinforcement and the lowest was for the knee without reinforcement. Poorer correlation was evident in the knee joint. The positive results of this study encourage the continued use of manual tests of muscle spasticity, using the Modified Ashworth Scale.