Parietal repetitive transcranial magnetic stimulation enhances functional connectivity in patients with minimally conscious state

Abstract

The basis of disorders of consciousness is the destruction of brain functional connectivity, and the restoration of damaged connectivity is considered as an indicator of consciousness recovery. The purpose of this study is to explore the effect of parietal repetitive transcranial magnetic stimulation (rTMS) on the changes of brain functional connectivity and consciousness recovery in patients with minimal conscious state (MCS) by electrophysiological (EEG) functional connectivity analysis, and to further explore the potential mechanism of consciousness recovery. In this study, 24 patients with MCS were randomly assigned to either real or sham rTMS group. The real rTMS group was applied to the parietal cortex at 10 Hz with 90% of the rest motor threshold, while the sham group underwent a similar procedure without cortical stimulation. Resting-state EEG and Coma Recovery Scale-Revised (CRS-R) scores were obtained before and after treatment. The Phase Locking Value (PLV) was calculated for the region of interest to assess the effect of parietal rTMS on functional brain connectivity. The CRS-R scores significantly improved after treatment in the real rTMS group, accompanied by increases in PLV, the default mode network (DMN), the frontoparietal network (FPN), and FPN-DMN connectivity. In contrast, the sham rTMS group showed no significant changes in CRS-R scores or EEG results. Moreover, alterations in FPN networks were positively correlated with changes in CRS-R scores. Parietal rTMS promotes the recovery of consciousness by fortifying large-scale brain connections and activating neural networks. In particular, FPN functional connections are closely linked to the early recovery of consciousness.