A COMPARATIVE STUDY ON THE INTER-RATER RELIABILITY OF THE ASHWORTH SCALES IN ASSESSMENT OF SPASTICITY

Abstract

Ashworth and modified Ashworth scales are the most widely used tests to assess the severity of muscle spasticity. These clinical scales offer qualitative and subjective information and consequently there are issues concerning reliability when two or more clinicians are involved in assessment of spasticity. This article presents the result of a study assessing inter-rater reliability of the original and of the modified Ashworth scales for the assessment of elbow flexor muscle spasticity in patients with hemiplegia. Thirteen patients with hemiplegia (8 men and 5 women) participated in this study. Two physiotherapists rated the muscle tone of elbow flexors according to the original and to the modified Ashworth scales. Each patient was assessed during a single session in a supine position on a bed with the arms at the sides of the body. Movements were performed three times by each assessor. No discussion of the results between the assessors occurred during the course of the study to ensure they were blind to each others’ results. Kappa values for the original Ashworth and the modified Ashworth scales were 0.22 (SE 0.27, P = 0.43) and 0.24 (SE 0.23, P = 0.24), respectively. The modified Ashworth scale was slightly more reliable than was the original scale but this difference was not significant (P > 0.05). Inter-rater reliability of the original and of the modified Ashworth scales in the assessment of elbow flexor spasticity was poor and therefore these spasticity scales may not be valid.