Cerebral Palsy Spasticity Scales

Cerebral Palsy Spasticity is defined as velocity dependent resistance of muscle to passive stretching.

Cerebral Palsy Spasticity increases with speed, and resistance is felt as a catch. It is assessed by passively moving the extremity through the range of motion to stretch the individual muscle groups, and Ashworth has described a five-point ordinal scale to grade the resistance felt. This Ashworth scale was modified by Richard W. Bohannon and Melissa B. Smith.

See Also: Brachial Plexus Palsy

Cerebral Palsy Spasticity Scales

There are many scales to assess the Cerebral Palsy Spasticity as the following:

Tardieu scale

Tardieu scale is a method of assessing Cerebral Palsy Spasticity. The Tardieu scale is considered to be more sensitive and specific with respect to other scales. It measures spasticity with the help of two parameters, namely spasticity grade Y and spasticity angle X, with respect to three stretch velocities, V1, V2, and V3.

Grading is done with the muscle to be tested at rest. It should be kept in mind that other joints must be kept in a constant position, including the neck, throughout the test and also in between tests. The velocity of the stretch is quantified as follows:

• V1: As slow as possible (minimizing stretch reflex).
• V2: Limb segment allowed to fall under gravity.
• V3: As fast as possible, faster than the natural drop of a limb with gravity.

V1 is used to assess the passive range of motion, whereas V2 and V3 are used to assess spasticity.

Spasticity Grade (Y):

• 0: No resistance during passive movement.
• 1: Slight resistance all along the course of the passive movement, with no definite catch at a precise angle.
• 2: Clear catch at a particular angle, interrupting the passive movement, followed by release.
• 3: Fatigable clonus (<10 seconds when maintaining pressure) occurring at a particular angle.
• 4: Infatigable clonus (>10 seconds when maintaining pressure) occurring at a particular angle.

Spasticity Angle (X):

Spasticity angle X is the difference between the angles of arrest at slow speed and catch-release/ clonus at fast speed. The evaluation involves two stretch maneuvers of the comfortably resting limb, one slow (V1) and one at the maximum speed possible for the examiner (V3).

V1 measures the passive range of motion, and the examiner makes a note of any movement arrest due to discomfort or mechanical resistance. The difference (Xv1 − Xv3) is the spasticity angle (X), which indicates the velocity-dependent stretch reflex. The larger this difference, the more spastic the muscle.

V2 is only feasible for extensors of the knee, wrist, and flexors of the elbow.

Note: it should be kept in mind that the angles are measured with respect to the muscle tested and not according to the anatomic principles so that 0° represents the position of minimal stretch on the muscle. For example, when the plantar flexors of the ankle are assessed, the angle 0° corresponds to the full plantarflexion position at the ankle.

Modified Tardieu Scale

To keep it simple, with the modified Tardieu scale (MTS), the examiner measures two joint angles, namely R1 and R2. R1 is the “angle of catch/ resistance,” which is elicited after a rapid velocity stretch, and R2 is the angle measured after a passive joint range of motion elicited after a slow velocity stretch to the maximum extent of exertion.

The difference between these two measurements indicates the dynamic component of spasticity, i.e., R2–R1.

If there is not much difference between R2 and R1, then it indicates static contractures that have been established in the affected muscle.

Modified Ashworth Scale

References

1. Bohannon RW, Smith MB. Interrater reliability of a modified Ashworth scale of muscle spasticity. Phys Ther. 1987 Feb;67(2):206-7. doi: 10.1093/ptj/67.2.206. PMID: 3809245.
2. Gracies J-M, Burke K, Clegg NJ, Browne R, Rushing C, Fehlings D, et al. Reliability of the Tardieu scale for assessing spasticity in children with cerebral palsy. Arch Phys Med Rehabil. 2010;91:421–428.
3. Boyd R, Graham H. Objective measurement of clinical findings in the use of botulinum toxin type A for the management of children with cerebral palsy. Eur J Neurol. 1999;6:S23–35.
4. Pandyan AD, Johnson GR, Price CI, et al. A review of the properties and limitations of the Ashworth and modified Ashworth Scales as measures of spasticity. Clin Rehabil 1999;13:373–383.