Intermittent theta burst stimulation modulates mirror visual feedback-induced rhythm suppression for hemiparetic upper extremity recovery after stroke

OBJECTIVE: Theta burst stimulation (TBS) and mirror visual feedback (MVF) reduce interhemispheric asymmetry in both hemispheres, which leads to motor recovery. This study aimed to investigate the modulatory effects of intermittent TBS (iTBS) with MVF in mirror therapy (MT) on hemiparetic upper extremity motor recovery and neurophysiological outcomes in patients with stroke. METHODS: We designed a randomized controlled trial with three parallel groups: (1) iTBS with MT; (2) sham iTBS with MT; and (3) iTBS with sham MT. Fifteen out of the included 36 patients with chronic stroke from these three groups respectively in the randomized trial, participated in the EEG evaluation to investigate MVF-induced sensorimotor event-related desynchronization (ERD) during mirror view and direct view conditions pre/post training. RESULTS: Patients who received iTBS with MT or sham MT demonstrated greater improvements in the Fugl-Meyer Assessment Upper Extremity distal sub-scores, in contrast to those who received sham iTBS with MT, whereas iTBS with MT yielded a greater improvement than the sham iTBS with MT among patients with lower upper extremity functioning. The EEG findings showed that iTBS with MT, but not the other two protocols, enhanced the beta ERD over the ipsilesional sensorimotor area. CONCLUSION: iTBS alone but not about the combination with MT appears to prime the ipsilesional motor cortex to be more receptive to MVF for motor recovery. The neurophysiological mechanisms of different brain stimulation protocols combined with MT with ERD neural substrates for post-stroke recovery can be further studied.