Electrophysiological Evaluation of the Modified Ashworth Scale in Assessment of Post Stroke Ankle Plantar Spasticity

Background: Spasticity is a common impairment following upper motor neuron lesions such as stroke. The appropriate measure of muscle spasticity, using validated tools to evaluate the outcome of therapies is important in clinical and research settings. Objective: To determine the concurrent criterion-related validity of the Modified Ashworth Scale in assessing post stroke Ankle flexor muscle spasticity based on its correlation with Modified Tardieu scale and the H-reflex tests. Methods: A total of 35 adult stroke participants underwent clinical and electrophysiological assessment of the ankle flexor muscle spasticity on the affected side. The primary outcome measures were: MMAS grade, R2−R1 of the MTS; and the H-reflex indices of H-max/M-max ratio. Results: Correlations tests revealed the correlation between the MMAS and MTS but did not reveal significant associations between the MMAS and the H-reflex tests. Conclusions: This study suggests that the MMAS may not be a valid tool to evaluate the ankle flexor muscle spasticity in these stroke participants. Key words: Stroke, spasticity, Modified Ashworth Scale, Tardieu Scale, H-reflex, criterion validity.