This study aimed to compare the effects of a combination of electrical stimulation with and without mirror visual feedback and kinesthetic motor imagery on the sensorimotor cortex of the non-dominant side and to explore the relationship between the bilateral sensorimotor cortices.
We recruited 16 healthy right-handed adults with a mean age of 34.6±11.9 years. Electrical stimulation was applied to the abductor pollicis brevis muscle of the non-dominant hand of each participant. Two experimental situations were randomized for each participant. One was electrical stimulation of the non-dominant hand with mirror visual feedback of the dominant hand to pick up objects for 30 seconds, and the other was electrical stimulation with sham mirror visual feedback to perform dominant hand pick up movements for 30 seconds. All participants were asked to imagine their non-dominant hand performing the same movements in each situation. The electrical stimulation was on for 2 seconds and off for 1 second. There was a rest period of 60 seconds between the two situations. Electroencephalography was recorded for each participant during the experiment. The relative power of the alpha band at the C4 electrodes was analyzed using a paired t-test to assess the significant difference between the two situations, and the correlation of the relative power of the alpha band between the C3 and C4 electrodes was analyzed using the Pearson correlation.
Electrical stimulation combined with mirror visual feedback and kinesthetic motor imagery showed significantly lower relative power in alpha band activities at C4 (11.81%) compared to electrical stimulation with sham mirror visual feedback (13.56%) (p=0.022). The relative power in alpha band activity at C3 was 11.88% during electrical stimulation with mirror visual feedback and kinesthetic motor imagery and was highly correlated with it at C4 (r=0.77, p0.001). There was no significant correlation between C3 and C4 during electrical stimulation with sham mirror visual feedback (p=0.19).
The combination of electrical stimulation with mirror visual feedback and kinesthetic motor imagery significantly modulates sensorimotor cortex activation, showing lower alpha power in C4 and a strong correlation between C3 and C4. This indicates improved bilateral sensorimotor interaction, which is not found in electrical stimulation with sham mirror visual feedback.
These findings suggest that this combined approach could benefit physiotherapy interventions. Future research should explore its potential to enhance interhemispheric coordination and support motor recovery, including its applicability to patients with peripheral nerve injuries in clinical applications.
electrical stimulation
EEG sensorimotor rhythms
