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.

Objective:To explore the clinical application values of radiofrequency thermocoagulation (RF-TC) based on stereotactic electroencephalogram (SEEG) high-frequency oscillations (HFOs) analysis in patients with refractory epilepsy.Methods:Fourteen patients with refractory epilepsy treated with SEEG-guided RF-TC were selected from Department of Neurosurgery, PLA Western Theater Command General Hospital from August 2019 to December 2021. Automatic detection algorithm of Matlab was used to calculate the HFOs incidence in each montage, and the fitting curves of HFOs incidences were used to formulate the threshold of HFOs and delimit the HFOs regions (ripples and fast ripples). These patients were divided into non-seizure group and seizure group according to the prognoses 3 and 6 months after RF-TC. At the last follow-up, these patients were divided into good prognosis group and poor prognosis group according to Engel grading; the differences of ripple thermocoagulation rate and fast ripple thermocoagulation rate between the 2 groups were compared.Results:A total of 7,332 ripples and 1,144 fast ripples were detected in SEEG data from 14 patients. Six months after surgery, neurological dysfunction incidence was 14.3%, without permanent neurological dysfunction, intracranial infection, intracranial hemorrhage, or electrode equipment failure. Within 3 months of RF-TC, seizure-free rate was 71.4% (10/14), and fast ripple thermocoagulation rate in non-seizure group was significantly higher than that in seizure group ( P<0.05); within 6 months of RF-TC, seizure-free rate was 57.1% (8/14), and ripple thermocoagulation rate in non-seizure group was significantly higher than that in seizure group ( P<0.05). At last follow-up, 6 patients had good prognosis and 8 patients had poor prognosis; the ripple thermocoagulation rate in good prognosis group was significantly higher than that in poor prognosis ( P<0.05). Conclusions:HFOs can assist in designating epileptogenic regions. Patients with wider range of thermocoagulation ripples or fast ripples will have better short-term efficacy; patients with wider range ofthermocoagulation ripples will have better prognosis.