Several studies have investigated possible role of repetitive transcranial magnetic stimulation (rTMS) in patients with disorder of consciousness (DOC). But the details of patients’ brain responses to the rTMS are yet to be disclosed. The aim of the study is to explore the neural electrical responses of DOC patients to rTMS modulation. DOC Patients [14 vegetative state, seven minimally conscious state (MCS)] and healthy subjects were enrolled and received one session of rTMS. The TMS-electroencephalogram was recorded at before and immediately after rTMS stimulation. TMS-evoked potentials as well as TMS-evoked connectivity were proposed to capture the effective connectivity alteration induced by rTMS. Significant changes of TMS-evoked potential were found in the healthy group but not in DOC patients. TMS-evoked connectivity was significantly enhanced by the rTMS in healthy and MCS groups. In addition, the enhancement was positively correlated with patients’ Coma Recovery Scale-Revised scores. Global synchrony of the TMS-evoked connectivity matrix significantly enhanced by rTMS in the control and MCS groups but not in vegetative state patients. Furthermore, after rTMS stimulation, the similarity of TMS-evoked connectivity patterns between pairwise patients was significantly raised in MCS patients. But no significant changes were found in vegetative state patients. TMS-evoked connectivity reveals that rTMS can effectively modulate effective connectivity of MCS patients, but no evidence of changes in vegetative state patients.
aDepartment of Neurosurgery, the Seventh Medical Center of PLA General Hospital, Beijing
bInstitute of Electrical Engineering, Yanshan University, Qinhuangdao
cDepartment of Vascular Neurosurgery, the Characteristic Medical Center of PLA Rocket Force
dState Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing
eDepartment of Basic Medical Science, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
* Dr. Xiaoyu Xia and Dr. Yong Wang contributed equally to the writing of this article.
Received 2 September 2019 Accepted 20 September 2019
Correspondence to Jianghong He, PhD, Department of Neurosurgery, the Seventh Medical Center of PLA General Hospital, Beijing 100700, China, E-mail: firstname.lastname@example.org