Objective:To investigate the characteristics and change trends of electroencephalogram (EEG) in patients with drug resistant epilepsy (DRE) after vagus nerve stimulation (VNS).Methods:Twenty-five patients with DRE, admitted to our hospital from July 2016 to May 2019, were chosen; all patients accepted VNS and followed up for 12 months. Long range video EEG (VEEG) monitoring was performed before VNS, and 3, 6 and 12 months after VNS, and the tracing time of each monitoring was longer than 12 h. The EEG characteristics of these patients before and different times after VNS were analyzed.Results:In the VEEG monitoring before VNS, 25 patients showed sharp wave, spike wave, sharp slow wave, and compound spike slow wave in the interictal period; 3 patients (12%) could locate the brain region. The interictal EEG of 11 patients 3 months after VNS showed different degrees of improvement as compared with the preoperative one, which manifested as mixed rhythms: mono-spiking as sharp wave, sharp slow wave or spike wave; 8 patients had McHugh grading I-II. The interictal EEG of 18 patients 6 months after VNS showed different degrees of improvement as compared with the preoperative one; 11 patients had McHugh grading I-II. The interictal EEG of 21 patients 12 months after VNS showed different degrees of improvement as compared with the preoperative one; 15 patients had McHugh grading I-II.Conclusion:The EEG improvement effect of DRE patients after VNS is gradually improved with time; in some patients, the EEG improvement is earlier than improvement of clinical symptoms.

Objective:To investigate the characteristics and change trends of electroencephalogram (EEG) in patients with drug resistant epilepsy (DRE) after vagus nerve stimulation (VNS).Methods:Twenty-five patients with DRE, admitted to our hospital from July 2016 to May 2019, were chosen; all patients accepted VNS and followed up for 12 months. Long range video EEG (VEEG) monitoring was performed before VNS, and 3, 6 and 12 months after VNS, and the tracing time of each monitoring was longer than 12 h. The EEG characteristics of these patients before and different times after VNS were analyzed.Results:In the VEEG monitoring before VNS, 25 patients showed sharp wave, spike wave, sharp slow wave, and compound spike slow wave in the interictal period; 3 patients (12%) could locate the brain region. The interictal EEG of 11 patients 3 months after VNS showed different degrees of improvement as compared with the preoperative one, which manifested as mixed rhythms: mono-spiking as sharp wave, sharp slow wave or spike wave; 8 patients had McHugh grading I-II. The interictal EEG of 18 patients 6 months after VNS showed different degrees of improvement as compared with the preoperative one; 11 patients had McHugh grading I-II. The interictal EEG of 21 patients 12 months after VNS showed different degrees of improvement as compared with the preoperative one; 15 patients had McHugh grading I-II.Conclusion:The EEG improvement effect of DRE patients after VNS is gradually improved with time; in some patients, the EEG improvement is earlier than improvement of clinical symptoms.