mas scale fpor spasticity
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Modified Ashworth Scale MAS spasticity grading criteria clinical use
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Here is a complete overview of the Modified Ashworth Scale (MAS) for spasticity:
Modified Ashworth Scale (MAS)
Background
- The original Ashworth Scale was published by Bryan Ashworth in 1964 to grade spasticity in multiple sclerosis patients. It used a 5-point scale (0-4).
- In 1987, Bohannon and Smith modified the scale by inserting a 1+ grade between grades 1 and 2, improving sensitivity for detecting mild spasticity.
- The MAS is now the most widely used clinical spasticity assessment tool in practice worldwide.
How to Administer
- The examiner passively moves the patient's limb through the full range of motion (ROM) at a high velocity (typically 1 second for the full arc).
- No specialized equipment is needed - just hands and a consistent technique.
- The patient should be relaxed and in a consistent position each time.
- Grade is assigned based on the resistance felt during passive movement.
MAS Grading Scale
| Grade | Description |
|---|---|
| 0 | No increase in muscle tone |
| 1 | Slight increase in muscle tone, manifested by a catch and release, or by minimal resistance at the end of range of motion when the affected part is moved in flexion or extension |
| 1+ | Slight increase in muscle tone, manifested by a catch, followed by minimal resistance throughout the remainder (less than half) of the ROM |
| 2 | More marked increase in muscle tone through most of the ROM, but affected part(s) easily moved |
| 3 | Considerable increase in muscle tone; passive movement is difficult |
| 4 | Affected part(s) rigid in flexion or extension |
Key Clinical Points
When to use:
- Stroke rehabilitation (tracking emergence/resolution of limb spasticity, deciding on splinting or pharmacotherapy)
- Spinal cord injury (SCI) - quantifying tone below the injury level
- Multiple sclerosis (MS)
- Cerebral palsy (CP)
- Traumatic brain injury (TBI)
Strengths:
- Quick to administer (a few minutes for multiple joints)
- No equipment required
- Easily integrated into routine exam
- Well-tolerated by patients
- Good interrater reliability in stroke, SCI, and MS - per [Bradley and Daroff's Neurology in Clinical Practice, p.1180]
Limitations:
- Does not assess spasm frequency or severity
- Does not differentiate between phasic and tonic components of spasticity
- Does not address functional disability directly - a lower MAS score does not necessarily mean improved motor control
- Scores can vary with patient positioning, posture, and limb position at time of testing
- Some authors argue it measures resistance to passive movement (muscle stiffness/contracture component) rather than true velocity-dependent spasticity
Compared to the Original Ashworth Scale
| Feature | Original Ashworth | Modified Ashworth (MAS) |
|---|---|---|
| Grades | 0, 1, 2, 3, 4 (5 points) | 0, 1, 1+, 2, 3, 4 (6 points) |
| Grade 1 meaning | No resistance | Catch + release / minimal resistance at end-range |
| Added grade | None | 1+ for catch + resistance through <50% of ROM |
| Sensitivity | Lower | Higher (especially for mild spasticity) |
Clinical Tip
For a comprehensive spasticity assessment, the MAS should be used alongside other tools such as:
- Pendulum test (pendulum drop of the limb)
- Tardieu Scale (more specific for velocity-dependent spasticity - considered by some to be more valid)
- Spasm frequency scales
- Functional outcome measures (FIM, Wolf Motor Function Test)
A tutorial demonstrating the MAS technique in practice:
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