In 1954, Tardieu and his colleagues originally introduced the concept of a ‘‘spastic reaction’’, as a muscle reaction produced by the passive stretching of a limb segment, depending upon the speed/ acceleration of the passive stretch differentiation between the neural component of resistance (spasticity) and soft tissue changes is necessary, as they respond to different types of treatment.

In a normal muscle contraction motor unit, the smallest functional unit involved in motor control. It consists of an alpha motor neuron, its axon and the muscle fiber that it innervates (Berne & Levy,1998).The pyramidal tract is a descending spinal pathway which is involved in the regulation of motor units and in controlling the speed and accuracy of voluntary movements (Berne & Levy, 1998). Muscle force is dependent upon the absolute number of functioning motor units and the firing rates of active motor units (Bourbonnais & Noven, 1989).

The Tardieu scale is a measure of spasticity most frequently used in the assessment of spasticity in children with cerebral palsy. It was originally introduced by Tardieu et al. in 1954 and has undergone two revisions. The first modification was performed by Held and Pierrot-Deseilligny in 1969, which was further modified and standardized by Boyd and Graham in 1999.

Ettie Ben-Shabat, et al (2013) conducted study on reliability of MTS and concluded that Intra- and interrater R1 and R2 measurements showed moderate to high reliability for the affected hamstrings, rectus femoris, gastrocnemius, soleus (mean ICC SD, .79.08), and tibialis anterior (mean k SD, .58.10). Only inter-rater measurements of the affected tibialis posterior were moderately reliable (R1Z.57, R2Z.77).

This latest version was called the Modified Tardieu Scale (MTS). The Tardieu scale has been stated to be superior to the Ashworth scale and the most appropriate outcome measure for spasticity because it adheres to Lance’s definition of spasticity and can differentiate spasticity from contracture, The Modified Tardieu Scale has been provided in recent publications.

Three components of the MTS to test spasticity are:

1. Velocity of stretch;
2. Quality of muscle reaction; and
3. Angle of muscle reaction.

The modified Tardieu scale determines the passive range of movement at different movement velocities, with the relative difference between a slow and a fast velocity passive stretch determining the dynamic component of the muscle contracture.

With the modified Tardieu scale, two resulting joint angles are measured by goniometer: the R1 angle which is the ‘angle of catch’ after a fast velocity stretch, and the R2 angle defined as the passive joint range of movement following a slow velocity stretch. The R2–R1 value indicates the level of dynamic contracture in the joint.

The key component of the MTS which is more important than the single measures of R1 and R2 is the dynamic component of spasticity calculated as the difference between R2 and R1 (R2–R1).

The relationship between R1 and R2 can help to estimate the contributions of neural and mechanical restraints to the resistance of passive movement. A large difference between R1 and R2 is indicative of spasticity.

A small difference between R1 and R2 is suggestive of soft tissue changes and contracture. The Tardieu scale specifies three velocities that can be applied to the muscle:

1. as slow as possible (V1),
2. the speed of the limb falling under gravity (V2), and
3. as fast as possible (V3; Boyd and Graham 1999).

V1 velocity is used to determine the R2 joint angle and either V2 or V3 is used to determine the angle of catch (R1 angle) depending on the muscle to be tested. The ‘catch’ following a fast velocity stretch is hypothesized to be the result of an overactive stretch reflex present in spastic muscle.

MODIFIED TARDIEU SCALE MUSCLE REACTION GRADINGS :

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• 0 –No resistance throughout the course of the passive movement
• 1 – Slight resistance throughout the course of the passive movement, with no clear catch at precise angle
• 2 - Clear catch at precise angle, interrupting the passive movement, followed by release
• 3 - Fatigable clonus (<10 seconds when maintaining pressure) occurring at precise angle
• 4 - Infatigable clonus (>10 seconds when maintaining pressure) occurring at precise angle