Ashworth Scale for Spasticity
Also known as: MAS, Modified Ashworth, spasticity assessment
The Modified Ashworth Scale (MAS) is a clinical rating scale for assessing muscle spasticity, quantifying the resistance to passive movement on a 0-4 scale plus an additional grade. Originally developed by B. Ashworth in 1964 and refined by Bohannon and Smith in 1987, the MAS is the most widely used bedside tool for evaluating spasticity in stroke survivors, individuals with cerebral palsy, multiple sclerosis, and spinal cord injury.
Key highlights
- Simple, quick (1-2 minutes per limb) bedside assessment requiring no equipment
- Universally recognized scale enabling communication across clinicians and facilities
- Grades capture clinically meaningful distinctions relevant to treatment decisions
- Changes in score correlate with clinical outcomes and functional improvement
Intuition
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How it works
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When to use it
The MAS is indicated for any patient with suspected spasticity from upper motor neuron lesions: stroke, spinal cord injury, cerebral palsy, traumatic brain injury, or multiple sclerosis. The scale assumes adequate patient cooperation and ability to relax. It is inappropriate for patients with primary hypokinetic movement disorders or rigidity.
Strengths & limitations
- Simple, quick (1-2 minutes per limb) bedside assessment requiring no equipment
- Universally recognized scale enabling communication across clinicians and facilities
- Grades capture clinically meaningful distinctions relevant to treatment decisions
- Changes in score correlate with clinical outcomes and functional improvement
- Subjective assessment highly dependent on examiner experience and sensitivity to resistance
- Ordinal scale where increments do not represent equal intervals; grade 1 to 2 difference not equivalent to 3 to 4
- Cannot distinguish true spasticity from rigidity or contracture without additional assessment
- Velocity-dependent assessment requires standardized movement speed; variations substantially affect results
Common pitfalls
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Applications
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Frequently asked
What does a Modified Ashworth Scale grade of 2 mean?
A grade of 2 indicates marked increase in muscle tone, with passive movement through range easy but requiring effort. This is moderate spasticity that may be functionally limiting in some positions but doesn't prevent the motion. Treatment is often considered at this level.
How is MAS different from the grade of 1+?
Grade 1 is a slight increase in tone with minimal resistance. Grade 1+ is slight increase in tone followed by a sudden brief catch (sudden stop) during the movement, then release. The catch is characteristic of velocity-dependent spasticity and indicates more significant underlying reflex hyperactivity.
Can spasticity assessed by MAS worsen or improve, and at what rate?
Spasticity patterns vary greatly. Post-stroke, spasticity often peaks at 3-6 months then may gradually improve with therapy, though not always. Some patients develop progressive spasticity; others maintain stable tone. Changes of one MAS grade typically represent clinically significant improvement or decline over weeks to months.
Why do some patients with high tone score low on the Ashworth Scale?
The MAS measures velocity-dependent spasticity in response to passive stretch. Some patients have fixed contracture (structural shortening) rather than spasticity; others have rigidity or hypokinesia that produces high tone but feels different from spasticity. Comprehensive assessment of passive versus active motion helps clarify the underlying problem.
Sources
- 1.Ashworth, B. (1964). Preliminary trial of carisoprodol in multiple sclerosis. Practitioner, 192, 540-542.
- 2.Bohannon, R. W., & Smith, M. B. (1987). Interrater reliability of a modified Ashworth scale of muscle spasticity. Physical Therapy, 67(2), 206-207.
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Cite this page
ScholarGate. (2026, June 3). Ashworth Scale for Spasticity. ScholarGate. https://scholargate.app/physical-therapy/spasticity-assessment-ashworth