A taVNS-TMS Study on Cortical Excitability for Post-Stroke Upper Limb Rehabilitation

Transcutaneous auricular vagus nerve stimulation (taVNS) has been shown to significantly enhance motor function in stroke rehabilitation. This study investigates the synergistic effects of combined taVNS and transcranial magnetic stimulation (TMS) on corticospinal excitability. A controlled experiment was conducted with five healthy individuals and ten stroke patients. Under optimized stimulation parameters, participants underwent TMS followed by five minutes of continuous taVNS. Resting-state electroencephalography(EEG) was recorded for three minutes before and after stimulation, while motor-evoked potential (MEP) parameters were collected from the contralateral muscles of the stimulated cortical region. Small-world network analysis was applied to EEG data, and cortical excitability was quantitatively assessed using TMS. Results revealed a significant increase in clustering coefficient in the total and α frequency bands, along with a reduction in characteristic path length (P < 0.05), indicating enhanced neural network efficiency. Combined stimulation led to increased MEP amplitude and reduced latency, with significant improvements observed in the experimental group. These findings suggest that taVNS-TMS intervention enhances cortical excitability, accelerates neural conduction, and promotes functional brain reorganization, offering promising therapeutic potential for stroke rehabilitation.