Modified Ashworth Scale (MAS)
What It Measures
The Modified Ashworth Scale grades how much resistance a limb gives when someone else moves it. The examiner takes a joint through its range and rates what they feel, from no increase in tone up to a limb held rigid.
Six grades are used: 0, 1, 1+, 2, 3, and 4. Grade 1 is a catch and release, or minimal resistance right at the end of the range. Grade 1+ is a catch followed by minimal resistance through less than half the range. Grade 2 is marked resistance through most of the range but the limb still moves easily; grade 3 makes passive movement difficult; grade 4 means rigid. The 1+ grade is what the 1987 modification added.
Further Reading
Additional Notes
Licensing Notes: The grade descriptions are reproduced without restriction across clinical resources, trial protocols, and government documents.
Learn More: Remember, muscle stiffness, contracture, joint changes, patient positioning, and examiner technique all affect what the examiner feels, and none of those is neural hyperexcitability — which is why the MAS is often described as a measure of muscle tone rather than spasticity specifically.
