Gadi Bartur1, Hillel Pratt2, Ruth Dickstein3, Silvi Frenkel-Toledo4, Amir Geva5, Nachum Soroker4. 1. Department of Physical Therapy, Faculty of Social Welfare and Health Studies, University of Haifa, Haifa, Israel; Department of Physical Therapy, Reuth Medical Center, Tel Aviv, Israel. Electronic address: bargad@hotmail.com. 2. Evoked Potentials Laboratory, Technion-Israel Institute of Technology, Haifa, Israel. 3. Department of Physical Therapy, Faculty of Social Welfare and Health Studies, University of Haifa, Haifa, Israel. 4. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Department of Neurological Rehabilitation, Loewenstein Hospital, Raanana, Israel. 5. Ben-Gurion University of the Negev, Beer-Sheba, Israel.
Abstract
OBJECTIVE: To investigate the neurophysiological manifestations of the mechanism underlying the effects of Mirror Visual Feedback (MVF) during manual movement. METHOD: Thirteen healthy right handed individuals were assessed while performing repeated unilateral wrist extension movements with and without MVF. The effect of MVF on EEG oscillations was studied in 3 distinct frequency ranges (low mu, high mu, low beta). RESULTS: Analysis of the low beta range showed that MVF reduces the magnitude of event-related de-synchronization (ERD) in the hemisphere contra-lateral to the moving hand. This effect reached significance when the moving hand was the dominant hand. In the analysis of the low mu range, bi-hemispheric amplification of ERD by the mirror pointed to an added effect of neural recruitment. This effect reached significance when the moving hand was the non-dominant hand. CONCLUSIONS: MVF applied during unilateral manual movement (a) attenuates hemispheric activation asymmetry, and (b) is likely to involve recruitment of the mirror neuron system. SIGNIFICANCE: As each of the above two effects reached significance only in one hand (dominant and non-dominant, respectively), clinical application of MVF might show a different level of efficacy in the treatment of right and left hemiparesis.
OBJECTIVE: To investigate the neurophysiological manifestations of the mechanism underlying the effects of Mirror Visual Feedback (MVF) during manual movement. METHOD: Thirteen healthy right handed individuals were assessed while performing repeated unilateral wrist extension movements with and without MVF. The effect of MVF on EEG oscillations was studied in 3 distinct frequency ranges (low mu, high mu, low beta). RESULTS: Analysis of the low beta range showed that MVF reduces the magnitude of event-related de-synchronization (ERD) in the hemisphere contra-lateral to the moving hand. This effect reached significance when the moving hand was the dominant hand. In the analysis of the low mu range, bi-hemispheric amplification of ERD by the mirror pointed to an added effect of neural recruitment. This effect reached significance when the moving hand was the non-dominant hand. CONCLUSIONS: MVF applied during unilateral manual movement (a) attenuates hemispheric activation asymmetry, and (b) is likely to involve recruitment of the mirror neuron system. SIGNIFICANCE: As each of the above two effects reached significance only in one hand (dominant and non-dominant, respectively), clinical application of MVF might show a different level of efficacy in the treatment of right and left hemiparesis.