Mirror movements induced by hemiballism due to putamen infarction: a case report and literature review

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

Objective

Mirror 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.

Methods

Sixty 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.

Results

In 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.

Conclusion

In 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.

Post Stroke Mirror Movements Preventing Performance of Bilateral Movements and Activities of Daily Living

Mirror movements (MMs) are involuntary synchronous movements of one limb during voluntary movements of the contralateral limb. Generally, MMs after stroke are observed in the unaffected hand during voluntary movements of the affected hand; MMs in the affected hand are comparatively rare. In previous studies, evaluation of MMs in the affected hand was performed using simple unilateral movement tasks, such as tapping or forceful repeated hand closure. However, the impact of MMs of the affected hand on functional tasks, such as activities of daily living (ADLs), has not been reported. We report the rare case of a patient with MMs of the affected hand due to atherothrombotic cerebral infarction of the right postcentral and precentral gyri. An 85-year-old Japanese man presented with left-sided hemiplegia and sensory impairment. MMs were observed in the left (affected) hand during many ADLs and could not be suppressed by the patient's will even when the examiner verbally instructed the patient to move only the unaffected hand. The patient was aware that his hand moved on its own, but he could not control it. The patient was trained on various types of bilateral coordinated motor exercises for 114 days after the MMs were first identified. However, this did not affect MM occurrence, and the MMs remained at the time of discharge. Future research is necessary to plan long-term interventions for MMs of the affected hand.

Mirror Movements in Acquired Neurological Disorders: A Mini-Review

Mirror movements (MMs) are specifically defined as involuntary movements occurring on one side of homologous muscles when performing unilateral movements with the contralateral limb. MMs have been considered a kind of soft neurological signs, and the persistence or reappearance of MMs in adults is usually pathologic. In addition to some congenital syndrome, MMs have been also described in age-related neurological diseases including pyramidal system diseases (e.g., stroke, amyotrophic lateral sclerosis) and extrapyramidal disorders (e.g., Parkinson's disease, essential tremor). With the advances in instrumentation and detection means, subtle or subclinical MMs have been deeply studied. Furthermore, the underlying mechanism is also being further elucidated. In this mini-review, we firstly discuss the MM examination means, and then review the literature regarding MMs in individuals with acquired neurological disorders, in order to further understand the pathogenesis of MMs.