Ashworth Scale (AS) and Modified Ashworth Scale (MAS)

Joints and muscles

The Modified Ashworth Scale is a 6-point scale. Scores range from 0 to 4, where lower scores represent normal muscle tone and higher scores represent spasticity or increased resistance to passive movement.

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 the range of motion when the affected part(s) 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 difficult

4 - Affected part(s) rigid in flexion or extension

Although there are no standardized guidelines for its use, the Modified Ashworth Scale can be applied to muscles of both the upper or lower body. Upper limb joints are generally tested with the child in supine, lower limb joints with the child in side lying.

The rater should extend the client’s limb from a position of maximal flexion to maximal extension until the first soft resistance is felt. Moving a client’s limb through its full range of motion should be done within one second by counting “one thousand and one”.  Throughout testing the client should be instructed to remain calm and relaxed, and when repeated testing is undertaken, testing should be initiated at the same time of the day to minimize possible changes in spasticity levels due to medication interaction (Bohannon and Smith, 1987).