Assessment of Motor Recovery after Stroke by EMG Analysis of Motor Reaction

J Korean Assoc EMG Electrodiagn Med 2004;6(1):38-44.
Published online May 10, 2004.

Abstract

Objectives: To investigate the relationship between EMG timing and activity and motor impairment, and to describe the value of EMG assessment for motor recovery after stroke. Methods: EMG signal of 18 stroke survivors was recorded during isometric contraction of shoulder and wrist joints along the audible beep. Motor impairment was assessed with the upper limb component of the Fugl-Meyer motor assessment (FMA) and was administered on the same day as the EMG assessments. Results: Delay in initiation and termination was significantly prolonged in the paretic arm and correlated significantly with FMA. Initiation delay was not significantly different between proximal and distal segments of the affected arm. However, termination delay of wrist contraction was significantly prolonged, compared to that of shoulder abduction. The root mean square of the agonist and antagonist during wrist contractions correlated significantly with FMA. Conclusion: Timing and strength of EMG have close relationship to motor impairment. Initiation delay of proximal muscle is expected to evaluate motor processing function for whole segment of the limb. Development of co-contraction may be a component of motor recovery sequence. Therefore, EMG assessment is likely to be useful outcome measure and also provide insights into mechanisms for motor recovery in stroke survivors.

Key Words: Motor impairment, Stroke, EMG