No Evidence of an Effect of a Single Mirror Visual Feedback Session on Subsequent Motor Imagery

Abstract

Motor imagery (MI) and mirror therapy, based on mirror visual feedback (MVF), are recommended as adjuncts to conventional therapies for upper limb rehabilitation after stroke. Both approaches activate sensorimotor cortical networks despite the absence of overt movement, and their concurrent application has been associated with enhanced neural activation. The present study investigated whether a single session of MVF modulates subsequent kinesthetic Motor Imagery (kMI)-related neural activity. EEG data from 38 healthy participants (MVF: n = 18; sham: n = 20) were analyzed in a mixed pre-post design. Participants performed kMI before and after either an MVF or sham intervention. Analyses focused on mu-band (8-12 Hz) event-related desynchronization (ERD) and its hemispheric lateralization. Although kMI reliably elicited stronger contralateral than ipsilateral mu ERD, MVF did not significantly affect subsequent kMI-related mu ERD or its hemispheric lateralization. These findings suggest that previously reported facilitatory effects of MVF on MI may be more closely related to concurrent application than to immediate aftereffects, while potential effects of repeated MVF exposure on subsequent MI remain to be investigated. These findings provide a foundation for future studies investigating how MVF and MI can be combined to optimize upper-limb stroke rehabilitation.