The inter rater reliability of the original and of the modified Ashworth scale for the assessment of spasticity in patients with spinal cord injury

Abstract

Thirty patients with spinal cord injury (SCI) were randomly selected to participate in this study which evaluated the inter rater reliability of the original and of the modified Ashworth scale for the assessment of spasticity in the lower limbs. A doctor and a physiotherapist rated the muscle tone of hip adductors, hip extensors, hip flexors and ankle plantarflexors according to the original and to the modified Ashworth scale. The results were analyzed using a Cohen's Kappa statistical test and showed varying levels of reliability for different muscle groups and limbs. Kappa values ranged between 0.21 and 0.61 (mean 0.37). The original scale was slightly more reliable than was the modified scale. However, this difference was not significant (P>0.05), and was not consistent between the two limbs and between different muscle groups.It was concluded that the Ashworth scale is of limited use in the assessment of spasticity in the lower limb of patients with SCI. Further work is required to establish a standardised speed of muscle stretching during the test, or to find more appropriate grades and descriptions of spasticity for this patient group. The effects of training of the raters in the use of the scales also warrants further investigation.

Modified Ashworth scale reliability for measurement of lower extremity spasticity among patients with SCI

“…Although this is an unconventional means of administering the MAS, this methodology allowed us to ensure a consistent velocity for assessment across subjects and raters as it was impractical to apply the velocity constraint on the first cycle. Despite this standardization of the measurement procedure, our results are similar to Haas et al 19 who compared the test-retest reliability of the Ashworth and MAS among subjects with SCI and lower extremity spasticity. In Haas' study, 19 the need to establish a standardized speed of muscle stretching during the test was identified.…”

“…Despite this standardization of the measurement procedure, our results are similar to Haas et al 19 who compared the test-retest reliability of the Ashworth and MAS among subjects with SCI and lower extremity spasticity. In Haas' study, 19 the need to establish a standardized speed of muscle stretching during the test was identified. In addition, they identified that the effects of rater training was not well evaluated.…”

“…Despite having fair intra-rater reliability and poor interrater reliability, an inappropriate level of confidence has been placed in the MAS as a lower extremity spasticity measurement tool. We concur with the opinion of Haas et al 19 that, 'ythe MAS is of limited use in the assessment of spasticity in the lower limb of patients with SCI' due to its inadequate reliability. Future research efforts should focus on identifying alternative tool(s) for quantification of lower extremity spasticity.…”

“…Haas et al 19 earlier reported the reliability of the MAS in the SCI population. A doctor and physiotherapist rated hip adductors, hip extensors, hip flexors and ankle plantar flexors using the MAS.…”

Spasticity after spinal cord injury

“…14,22 While the Ashworth and modified Ashworth scales 14,15,23 are commonly used to assess the severity of spasticity, there is some question about their validity in the lower limbs of persons with SCI. 24 As spasticity outcomes vary between clinical patient groups and depend on a variety of factors within each individual, a battery of assessment tools is recommended, incorporating clinical, electrophysiologic, neurophysiological, 25 and/or biomechanical techniques. 14,26,27 It is important to note that there are generally poor correlations among clinical scales and, further, reductions in spasticity are not necessarily correlated with improvement in function.…”