Specificity Analysis Of High Frequency Oscillations Captured By Deep Intracranial Electrodes During Ictal Period In Patients With Refractory Epilepsy

Objective: This research mainly explores the space distribution characteristics of ripples with automatic detection method,analyzing the connections between surgical outcomes and ripples.Finally,concluding the clinical implications of the results.Methods: the original EEG information of patients with refractory epilepsy who were monitored by intracranial electrode video electroencephalogram before resection is collected.The computer software MATLAB and Brainstorm were used to run highly sensitive high-frequency automatic detection algorithm(CS algorithm)to analyze the original EEG information and detect ripple waves in the ictal periods.The spatial distribution of ripples is observed,comparing the ripple rates of the SOZ area with them in the non SOZ area.The average ripple rate of surgery area and non-surgical removal area are calculated,comparing the ripple wave removal ratio between good postoperative effect group and poor postoperative effect group.Results: The mean follow-up time was 17.46±4.427 months,and the mean medical history was 20.08±12.53 years.A total of 116 electrodes were implanted,with a total of 1416 contacts.In ictal period,the average ripple rate in SOZ region and non-SOZ region is(1.96±0.70/min vs 1.81±0.87/min,p=0.496).,there was no significant difference.The ripple rate in surgical region and non-surgical region is(1.31±0.74/min vs 1.13±0.38/min,p=0.235),there was no significant difference.the ripple wave removal ratio in good postoperative effect group and poor postoperative effect group is(-0.129±0.197 vs-0.145±0.165,F=1.415,P=0.431),there was no significant difference.Conclusion: the automatic analysis results showed that Ripple rate could not distinguish SOZ zone from non-SOZ zone in ictal period.High ripple rate was not corresponding to SOZ zone.Ripple rate could not distinguish between surgical resection area and non-surgical resection area,and high ripple rate also existed in non-surgical resection area.There was no significant correlation between ripple resection rate and postoperative effect.it is currently not possible to predict postoperative effect by preoperative calculation of ripple resection rate,nor to predict and evaluate the size of epileptic area by ripple rate.