Surface electromyography analysis of mirror movements under unilateral movement in stroke patients: A retrospective study

Abstract

ObjectiveMirror movements (MMs) are common abnormal motor performance in patients with poststroke hemiparesis. The study aimed to utilize the Electromyography (EMG) characterization of MMs in stroke patients and explore the relationship between MMs and the motor function of affected limbs.MethodsSixty patients with stroke who had used to undergo clinical assessment and surface Electromyography (sEMG) were selected in this study. We investigated the standardized net excitation (SNE) and overflow percentage (OF) as a measure of mirror activities on bilateral muscles of stroke patients.ResultsIn stroke patients, mirror activities occurred in both affected and unaffected muscles during maximal contractions. We found that OF at unilateral contraction on the affected side (UCA) was significantly greater than that at unilateral contraction on the unaffected side (UCU). Additionally, a negative correlation between OF at UCA and Brunnstrom stages on admission and discharge. However, there were no significant correlations between OF and disease duration, Barthel Index, or the degree of improvement in all clinical evaluations. We still found a positive correlation between SNE at UCA and the improvement of the Brunnstrom stage of the hand. But we could not find any significant correlation between SNE and other clinical evaluation scores.ConclusionIn conclusion, the study found mirror activities in both affected and unaffected muscles, confirming an asymmetry between them. Although the mechanisms are still unclear, we confirmed a significant correlation between MMs at UCA and the motor function of the affected upper extremity, which might provide further evidences for understanding MMs in stroke patients and a new research direction on evaluation for motor function and outcomes of stroke patients.

Assessment of Brain Inhibitory Function in Physical Therapy

“…In addition, it has been suggested that motor overflow may be a clinical indicator of the recovery process of motor function after stroke. In addition, a correlation between motor overflow occurring on the nonoperating side and muscle activity on the operating side has been reported for unilateral upper limb movements after stroke [40]; in this study, EMG was used to assess motor overflow in 60 patients with stroke. The participants performed unilateral elbow flexion exercises for 5 seconds on both sides.…”

“…Figure 2.Comparison between OF′AEMG and OF′RMS of bilateral biceps brachii during a unilateral contraction task[40]. AEMG represents the mean amplitude of the electromyography waveform.…”

Upper extremity asymmetry due to nerve injuries or central neurologic conditions: a scoping review

“…Eleven articles studied UE asymmetry during indirect periodic movements (e.g., gait, etc.) [106][107][108][109][110][111][112][113][114][115][116][117][118][119][120][121]. Some excluded studies were designed to assess a specific device's design [122][123][124][125], focused on mathematical modelling and analysis of the asymmetries [111,[126][127][128][129][130], or did not study the UE asymmetry resulting from any specific neurological condition (e.g., ).…”