Inter-rater reliability of the Ashworth scale in multiple sclerosis

Abstract

A study of 30 patients with multiple sclerosis was undertaken to determine the inter-rater reliabilty of the Ashworth scale for the clinical assessment of spasticity in the lower limbs. Scores of two physiotherapists were compared. Kendall's tau correlation coefficients higher than 0.60 were found for M soleus, M gastrocnemius and for the M psoas. For the adductors and the internal rotators of the hip, the interrater reliability according to Kendall's tau was lower than 0.55. For the M quadriceps and the flexors of the knee, Kendall's tau correlations were higher on the left side than on the right side. No explanation could be found for this inconsistent finding. It was concluded that the Ashworth scale may be used as a reliable scale for some muscles but not for others. More research is needed to find out if differences in ratings could be explained by fluctuations or differences in the clinical assessment of the muscle tone.