The relation between Ashworth scale scores and the excitability of the α motor neurones in patients with post-stroke muscle spasticity. Issue 5 (1st May 2003)

• Record Type: Journal Article
• Authors: Bakheit, A M O; Maynard, V A; Curnow, J; Hudson, N; Kodapala, S
• Is Part Of: Journal of neurology, neurosurgery and psychiatry. Volume 74:Issue 5(2003)
• Page Start: 646
• Page End: 648
• Publication Date: 2003-05-01
• Subjects: Ashworth scale -- α motor neurone -- spasticity; Neurology -- Periodicals; Nervous system -- Surgery -- Periodicals; Psychiatry -- Periodicals; 616.8
• DOI: 10.1136/jnnp.74.5.646
• Languages: English
• ISSNs: 0022-3050

Abstract

Abstract : Background: The modified Ashworth scale (MAS) is the most widely used method for assessing muscle spasticity in clinical practice and research. However, the validity of this scale has been challenged. Objectives: To compare the MAS with objective neurophysiological tests of spasticity. Methods: The MAS was recorded in patients with post-stroke lower limb muscle spasticity and correlated with the excitability of the α motor neurones. The latter was evaluated by measuring the latency of the Hoffmann reflex (H reflex) and the ratio of the amplitude of the maximum H reflex (Hmax ) to that of the compound action motor potential of the soleus muscle (Mmax ). Results: Data on 24 randomly recruited patients were analysed. Patients were divided into two groups according to their MAS score: 14 had a MAS score of 1 (group A) and 10 scored 2 (group B). The two groups were comparable with respect to age and sex, but in group A there was a longer period since the stroke. The H reflex latency was reduced and the Hmax :Mmax ratio was increased in both groups. The Hmax :Mmax ratio values were higher for group B but the differences were not statistically significant. Conclusions: There is a relation between the MAS scores and α motor neurone excitability, although it is not linear. This suggests that the MAS measures muscle hypertonia rather than spasticity.