Parietal rTMS Induced Changes in Cortical Excitability in Patients With Minimally Conscious State Using TMS-EEG.

Objective: To verify the effectiveness of the parietal repetitive transcranial magnetic stimulation (rTMS) and take advantage of TMS-EEG to assess cortical excitability in patients with minimally conscious states (MCS).

Methods: We enrolled 10 MCS patients who received 10 sessions of 10 Hz rTMS on the parietal cortex for 10 consecutive days and then 10 days of sham stimulation after a 14-day wash-out period. The Coma Recovery Scale-Revised (CRS-R) and TMS-EEG were used to assess the levels of consciousness and cortical excitability before and after active and sham stimulation, respectively.

Results: Compared to sham stimulation, the CRS-R revealed a significant improvement after receiving active rTMS. The amplitude of components of TMS-evoked potential after active stimulation significantly increased at 30, 60, and 180 ms, respectively; global brain power increased significantly. The PCIst values had a significant difference after active rTMS stimulation, and the CRS-R scores showed a significant correlation with PCIst values before and after active stimulation.

Conclusion: High-frequency rTMS on the parietal cortex has therapeutic efficacy and can improve cortical excitability in MCS patients.

Significance: Our results provide preliminary evidence to support the use of the parietal area as a potential therapeutic target for MCS patients in clinical practice.