Objective: To investigate the criterion validity of the modified Ashworth Scale.
Population: Volunteers from a stroke population admitted to a district general hospital stroke unit diagnosed with a first ever stroke less than 26 weeks previously.
Outcome measures: Resistance to passive movement about the elbow was simultaneously quantified (biomechanically) and graded (modified Ashworth Scale). Passive range of movement and peak instantaneous velocity during passive movement were also measured.
Analysis: Criterion validity was investigated as convergent construct validity (using the Spearman's correlation coefficient) and concurrent validity (using analysis of variance).
Results: One hundred measurements were taken on 63 subjects. Correlation between the modified Ashworth Scale and resistance to passive movement was 0.511. Resistance to passive movement and velocity showed significant differences between the modified Ashworth score of ‘0’ and a modified Ashworth score greater than ‘0’ (p < 0.01). There were no significant differences between MAS ‘1’, ‘1+’ and ‘2’. Resistance to passive movement in the impaired arm was significantly higher than in the nonimpaired arm (p < 0.01).
Conclusion: The modified Ashworth Scale does not provide a valid measure of spasticity at lower grades but it may provide a measure of resistance to passive movement.
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References
1.
Lance JW. Pathophysiology of spasticity and clinical experience with baclofen. In: Lance JW, Feldman RG, Young RR, Koella WP eds. Spasticity: disordered motor control. Chicago: Year Book, 1980: 185–204.
2.
Sheean G. Neurophysiology of spasticity. In: Barnes MP, Johnson GR eds. Upper motor neurone syndrome and spasticity: clinical management and neurophysiology. Cambridge: Cambridge University Press, 2001: 12–78.
3.
Barnes MP. An overview of the clinical management of spasticity. In: Barnes MP. Johnson GR eds. Upper motor neurone syndrome and spasticity: clinical management and neurophysiology. Cambridge: Cambridge University Press, 2001: 1–11.
4.
Pandyan AD, Price CIM, Curless RH, Barnes MP, Johnson GR, Rodgers H. A review of the properties and limitations of the Ashworth and modified Ashworth Scales. Clin Rehabil1999; 13: 373–383.
5.
Pandyan AD, Price CIM, Rodgers H, Barnes MP, Johnson GR. Biomechanical examination of a commonly used measure of spasticity. Clin Biomech2001; 16: 859–865.
6.
Ashworth B. Preliminary trial of carisoprodal in multiple sclerosis. Practitioner1964; 192(April): 540–542.
7.
Bohannon RW, Smith MB. Inter rater reliability of a modified Ashworth Scale of muscle spasticity. Phys Ther1987; 67: 206–207.
8.
van Wijck FMJ, Pandyan AD, Johnson GR, Barnes MP. Assessing motor deficits in neurological rehabilitation: patterns of instrument usage. Neurorehabil Neural Repair2001; 15: 23–30.
9.
Pandyan AD, Vuadens P, van Wijck FMJ, Stark S, Johnson GR, Barnes MP. Are we underestimating the clinical efficacy of botulinum toxin (type A)? Quantifying changes in spasticity, strength, and upper limb function after injections of Botox® to the elbow flexors in a unilateral stroke population. Clin Rehabil2002; 16: 654–660.
10.
Sherwood AM, Graves DE, Priebe MM. Altered motor control and spasticity after spinal cord injury: subjective and objective assessment. J Rehabil Res Dev2000; 37.
11.
Trochim, W. The Research Methods Knowledge Base, first edition. Cincinnati, OH: Atomic Dog Publishing, 1999. Accessed January 2003 from http://trochim.human.cornell.edu/KB/index.htm
12.
Devasahayam SR. Signals and systems in biomedical engineering: signal processing and physiological systems modelling. New York: Kluwer Academic/Plenum Publishers, 2001: 5-5.
13.
Nuyens G, De Weerdt W, Ketelaer P et al. Inter rater reliability of the Ashworth Scale in multiple sclerosis. Clin Rehabil1994; 8: 286–292.
14.
Pandyan AD, Cameron M, Powell J, Stott DJ, Granat MH. Contractures in the post stroke wrist: a pilot study of its time course of development and its association with upper limb recovery. Clin Rehabil2003; 17: 88–95.
15.
Lieber RL. Skeletal muscle structure and functionImplication for rehabilitation and sports medicine. London, Williams & Wilkins, 1992.
16.
Goldspink G, Williams P. Muscle fibre and connective tissue changes associated with use and disuse. In: Ada L, Canning C eds. Key issues in neurological physiotherapy. Oxford: Butterworth & Heinemann, 1990: 127–218.
