An Epileptogenic Networks Study Of Premotor Cortex Based On Stereo-electroencephalography

Objective:Using the data of patients with pre-motor area epilepsy who underwent multimodal assessment and were verified by SEEG in the second hospital of Lanzhou University,we constructed and analyzed the pre-motor area epileptogenic network by manual analysis,HFEI and EI;compared the differences between HFEI,EI and manual analysis to epileptogenic network,and verified the value of EI and HFEI in clinical application;combined with the literature,we analyzed the epilepsy symptomatology and epileptic network of premotor area,we also analyzed clinical value of EI and HFEI.Methods:A retrospective analysis was made of the patients with premotor epilepsy who underwent multimodal evaluation and were verified by SEEG in neurosurgery of the second hospital of Lanzhou University.The clinical data of all patients included:detailed medical history,physical signs,VEEG,3D MRI,thin-layer CT,PET-CT and SEEG,and mapping data based on SEEG.The epileptogenic network was visually analyzed by three teachers of neuroelectrophysiology.According to the seven common onset electroencephalogram manifestations : low voltage fast activity,low-frequency and high-amplitude periodic spikes,spike activity <13Hz,rhythmic spike-slow wave activity,high-amplitude fulminant multispike rhythm,Delta brush,and burst-suppression.The electrode contact for early abnormal electroencephalography was determined,the corresponding brain area forms the epileptogenic network,and the epileptic areas involved in epileptic spikes in the seizure period form the epileptic transmission network;the epileptogenic network construction method of HFEI: quantify the SEEG data of patients to get the HFEI andthreshold value of different brain areas at the onset of seizure,count the electrode contact greater than the threshold value as the high epileptogenic contact,and the corresponding brain area aggregation forms the epileptogenic network based on HFEI;the epileptogenic network construction method of EI: quantify of SEEG data of patients to get EI,take 0.4 as the threshold,count the electrode contact with EI greater than 0.4 as the high epileptogenic contact,corresponding to the aggregation of brain regions to form epileptogenic network based on EI.According to the results and literature analysis of epileptic network model of premotor epilepsy,analysis the differences between HFEI and EI.The end,and analysis the clinical application value of the two indicators.Results:Three patients were included in the study,with a total of 248 electrode contacts included in the analysis.According to the manual analysis,39 electrode contacts were involved in the early stage of seizures,and 209 electrode contacts without abnormal involvement in the early stage of seizures.According to the HFEI,the total electrode contacts number of over the threshold was 29,and 219 were below the threshold.According to the EI,the total electrode contacts number of over the threshold was was 39,and 209 were below the threshold.Artificial analysis in this study was consistent with the epileptogenic network obtained by HFEI analysis: one case was Broca language area ? dorsolateral of brodmann area 6,one case was dorsolateral of brodmann area 6?primary motor area,one case was frontal eye area? dorsolateral of brodmann area 6;epileptogenic network analysis of EI,one case was Broca language area?dorsolateral of brodmann area 6,one case was dorsolateral of brodmann area 6?ipsilateral primary motor area and contralateral dorsolateral of brodmann area 6,and one case was frontal eye area?dorsolateral of brodmann area6.The epileptogenic network analyzed by the three methods conformed to the law of frontal lobe epilepsy conducting from front to back.The resulting premotor area epilepsy transmission network was manifested in one case by extensive dissemination to the SMA-preSMA-the frontal eye area-the-primary motor areathe-primary sensory area-the lateral superior temporal gyrus,one case by dissemination to the another sideof dorsolateral of brodmann area 6,and one to the primary motor area.Premotor area epilepsy mainly manifests as backward conduction,but also can appear to the opposite mirror site conduction;premotor area epileptogenic network and transmission network preferentially involve other brain areas within the motor system,and some cases can also affect outside the motor system.Comparing the epileptogenic network analyzed by HFEI and EI with the epileptogenic network analyzed manually,the specificity of HFEI was 0.96,while its sensitivity was 0.54;the specificity of EI was 0.91,and the sensitivity was 0.54.Both indicators showed high specificity,which proved that HFEI and EI could assist the analysis of epileptogenic network in clinic.Statistical analysis of HFEI and EI showed that p=0.175,indicating that there was no significant difference between the two methods in clinical analysis of epileptogenic network.Conclusion:1.The epileptogenic network of premotor area epilepsy is characterized by conduction from front to back,which is consistent with its fiber connection and physiological signal transmission direction.In addition,premotor area epilepsy can be transmitted to the opposite mirror image site.The epileptogenic network of premotor area is generally composed of brain areas within the motor system,and part of it can also be transmitted to brain areas outside the motor system.2.SEEG can effectively locate epileptogenic areas and analyze the corresponding epileptogenic networks;EI and HFEI analysis of epileptogenic networks have high specificity,both indicators can assist in locating epileptogenic areas in clinical practice,and there is no significant difference between the two clinical applications.