Modified Ashworth Pro (MAS)
Standardized Hypertonia & Spasticity Scoring HUD
Select MAS scores (0-4)
to visualize Spasticity Intensity
Standardized Scoring Definition
The MAS is a 6-point scale used to describe muscle tone. It ranges from **0** (No increase in tone) to **4** (Limb rigid in flexion or extension). Grade **1+** was added to indicate resistance through less than half of the joint's range of motion.
MAS Assessment Guide
- Grade 0: No increase in muscle tone.
- Grade 1: Slight increase in tone, catch and release at end ROM.
- Grade 1+: Slight increase in tone, catch followed by minimal resistance through < 50% ROM.
- Grade 2: More marked increase in tone through most ROM, limb easily moved.
- Grade 3: Considerable increase in tone, passive movement difficult.
- Grade 4: Affected part(s) rigid in flexion or extension.
Frequently Asked Questions
What is considered a 'Normal' muscle tone?
A score of **0** is considered normal tone, where no increase in resistance is felt during passive movement.
Does MAS measure strength?
No. The MAS measures **tone (spasticity)**, not volitional strength. High spasticity can coexist with significant muscle weakness (paresis).
Is the MAS valid for Cerebral Palsy?
Yes, it is frequently used in pediatric populations to justify Botulinum Toxin (Botox) injections and monitor surgical outcomes.
Why MAS Scores are Critical for US Insurance
In the US healthcare system, documentation of a **MAS score ≥ 3** is often a prerequisite for the authorization of pharmacologic interventions such as intrathecal baclofen pumps or focal neurolysis with Botox injections.
Clinical Bibliography
- 1. Bohannon RW, Smith MB. Interrater reliability of a modified Ashworth scale of muscle spasticity. 1987.
- 2. Pandyan AD, et al. A review of the properties and limitations of the Ashworth and modified Ashworth Scales. Clin Rehabil. 1999.
CLINICAL RESOURCE