Inter- and intrarater reliability of the Ashworth Scale and the Disability Assessment Scale in patients with upper-limb poststroke spasticity

Objective: To evaluate the reliability of the Ashworth Scale and the Disability Assessment Scale (DAS) in poststroke patients with upper-limb spasticity and functional disability. Design: Single trial. Setting: University medical center. Participants: Nine patients ≥6 months poststroke with upper-limb spasticity and impairment in the areas of hygiene, dressing, limb posture, or pain were included in the analysis. Interventions: Ten experienced medical professionals rated each patient in randomized order twice on the same day (results based on mean of evaluations at times 1 and 2). Elbow, wrist, finger, and thumb flexion tones were assessed by using the Ashworth score (range, 0-4), and functional disability was assessed using the DAS (range 0-3). Main Outcome Measures: Intra- and interrater reliability of the Ashworth Scale and DAS. Results: For the Ashworth parameters, 38 of 40 evaluations indicated excellent (weighted _κ≥.75) or good (weighted _κ≥.4) intrarater reliability. For DAS parameters, 31 of 40 evaluations indicated excellent or good intrarater reliability. The interrater reliability was also good for both the Ashworth Scale (Kendall W=.598-.792) and DAS (Kendall W=.494-.772) with statistically significant agreement found among raters (all P<.001). Conclusions: In patients with upper-limb spasticity after stroke, the Ashworth Scale and DAS had good intra- and interrater reliability when used by trained medical professions.