Objective To study the diversities of imaging, symptoms, electrophysiology and clinical value of the stereoelectroencephalography(SEEG) in patients with mesial temporal lobe epilepsy.Methods Eight patients with intractable epilepsy in Epilepsy Center of Yuquan Hospital of Tsinghua University who underwent mesial temporal lobectomy were recruited in this study, and their epileptic foci could not be accurately positioned.Therefore stereotactic brain electrodes were implanted, and their usual attack originated from mesial temporal lobe structure were confirmed.There was no seizure in the one year follow-up.Results Symptoms of the eight patients behaved differently, and the onset of the seizures in scalp electroencephalograph or SEEG showed diversities.Epileptic discharges were found originated from the mesial temporal lobe after implanting electrodes: in the early stage of discharges, four cases had the conduction to insular lobe structure;two cases had the conduction to contralateral mesial temporal lobe;one case had the conduction to retrosplenial cortex;one case had the conduction to parietal lobe;one case had the conduction to frontal lobe and rapid generalization (one case had the conduction to insular lobe and contralateral mesial temporal lobe meanwhile).Conclusions There is difference in clinic, imaging and electrophysiology of the patients with mesial temporal lobe epilepsy The non-specificity can be explained by the evolution of the intracranial electroencephalography, which can help us know its network conduction pattern Insular lobe is the most common conduction approach of mesial temporal lobe epilepsy in early stage SEEG can be used as a microinvasive, accurate preoperative localization method, which can help us to locate accurately and understand the discharges and conduction mode.

ObjectiveTo investigate the clinic and pathologic features of one patient diagnosed with neurocutaneous melanosis ( NCM ) by biopsy.MethodsA 21-year-old woman presented with a 2-month history of tinnitus,headache,vomiting and 1-month history of impaired vision.At birth,a massive nevus covering most of the posterior abdomen had been noted as well as the presence of multiple smaller lesions all over the body.Magnetic resonance imaging demonstrated a posterior fossa cyst compatible with the Dandy-Walker syndrome and extensive leptomeningeal enhancement. Surgery was performed to cystectomy and to obtain pathologic specimens from the leptomeninges. Biopsy and immunohistochemical study was performed.ResultsAt surgery,diffuse black pigmentation of the leptomeninges and the cyst was found.Under microscope,the cyst and leptomeninges were composed with melanocytes with variable pigmentation.Those cells positive for HMB45,MelanA,S100 and vimentin.Ki-67 positive cells ＜ 1％.The pathologic diagnosis wasleptomeningeal diffusemelanocytosis. Thepatientdied 2months after thesurgery.ConclusionsNCM is characterized by a focal or diffuse proliferation of melanin-producing cells in both the skin and the leptomeninges.NCM could be compatible with the Dandy-Walker syndrome.Definite diagnosis relies upon the histological data obtained by mean of biopsy.

Objective To propose a novel stereo-electroencephalography(SEEG) quantitative measure analyzing ictal high frequency (60-90 Hz) and calculating high frequency epileptogenicity index (HFEI) to localize epileptogenic zone and evaluate epileptogenic network. Methods The clinical presurgical evaluation and SEEG data of 15 patients who were performed SEEG electrodes implantation from April 2015 to March 2016 were analyzed retrospectively. Post-implantation head CT images and 3D MRI data were fused for accurately identifying and locating each electrode contact. Ictal SEEG quantitative measure HFEI was calculated and threshold was set. The epileptogenic network was divided into focal, regional, multiple regional and bilateral ones and the results were compared with the pathological results.Results The epileptogenic network was focal for four patients, regional for four patients, multiple regional for six patients and bilateral for one patient (7/15). In terms of the pathology,two cases with hippocampal sclerosis both showed regional network. In four cases with cerebral malacia, two cases showed multiple regional network and the other two cases showed focal network. In six cases with cortical malformation, three cases showed multiple regional network, the other three cases showed focal, regional and bilateral networks respectively. Conclusions We explored a novel SEEG quantitative measure based on the high frequency power analysis,which is objective and could localize epileptogenic zone and evaluate the epileptic network.

Objective:To analyze the characteristics of stereoelectroencephalography (SEEG) in children with drug-resistant epileptic spasms (ES), and to explore the surgical strategy of children with spastic seizure under the guidance of SEEG.Methods:The clinical data of 156 children with ES who were preoperatively evaluated in the Department of Neurosurgery Ward 3, Tsinghua University Yuquan Hospital from January 2014 to December 2021 were retrospectively reviewed.All children were evaluated in the second stage of stereotactic electrode placement after a non-invasive preoperative evaluation.The characteristics of intracranial EEG, surgical strategy and prognosis were analyzed.Results:A total of 19 eligible children were included, involving 13 boys and 6 girls.The age of first onset and surgical age of them ranged 1 month to 4 years, and 2 years to 13 years, respectively.The SEEG was divided into 3 types in children with ES at the onset.Five children were SEEG type A, presenting with the focal seizure discharges at the beginning and a gradual propagation to widespread fast-wave bursts.Ten children were SEEG type B, presenting a focal leading spike followed by diffused fast-wave bursts.Four children were SEEG type C, presenting a diffuse fast wave rhythm onset.Although some electrode discharges appeared slightly " leading", they covered more than one brain region.After focal resection or thermocoagulation, 13/19 patients did not have the onset of seizures, and 5/19 and 8/19 were graded as SEEG type A, and B, respectively.During the intermittent period of SEEG attacks in children with SEEG type A and B, a significant phenomenon of focal epileptic discharge consistent with the onset of the attack was observed, and surgical removal of these areas effectively controlled spastic seizures.Conclusions:Epileptic spasms may be triggered by a focal neocortical discharge.Intracranial EEG showed that the focal seizure onset evolves into spasm or a focal " leading spike" is a good indicator of surgical prognosis.

Objective:To study the localization value of stereoelectroencephalography (SEEG) in refractory epilepsy associated with tuberous sclerosis complex (TSC), and to analyze the prognosis related factors.Methods:A case control study.Data of 66 patients with TSC-related refractory epilepsy who underwent SEEG placement at the Epilepsy Center of Tsinghua University Yu-Quan Hospital from January 2014 to March 2023 were retrospectively analyzed, including medical history, seizure semiology, scalp electroencephalogram (EEG), imaging, and SEEG findings.Patients were divided into a seizure-free group and a seizure group according to the seizures after surgery. t/ χ2 test was used to compare the relationship between age of onset, age of surgery, duration of epilepsy, genetic findings, seizure symptoms, scalp EEG characteristics, SEEG placement protocol and prognosis. Results:A total of 66 patients met the enrollment criteria, of whom 55 patients were seizure-free after surgery (seizure-free group), and 11 patients still had seizures (seizure group).Among the 66 patients, there were 46 males and 20 females; the age of onset was (21.72±30.01) months; the age of SEEG surgery was (6.79±5.12) years; the duration of epilepsy was (4.98±4.11) years.SEEG results showed that seizures started with a single tuber in 43 patients (64.4%), seizures started with 2 or more tubers in one hemisphere in 16 patients, and 7 patients had bilateral multi-tubers or the pathogenic tuber(s) could not be identified.The following factors were found to be associated with prognosis: early age of surgery ( t=-3.463, P<0.01), ictal scalp EEG with a definite lateralization ( χ2=7.876, P<0.05), and the concordance of interictal and ictal EEG ( χ2=6.821, P<0.05).The age of onset, duration of epilepsy, seizure type and symptom, genetic findings, and SEEG placement protocol were not significantly correlated with prognosis.The results of SEEG identified that onset with a single tuber revealed a better postoperative outcome. Conclusions:This study confirms the safety and efficacy of SEEG in TSC-related refractory epilepsy, and also finds that ictal EEG is uniquely valuable in guiding SEEG placement for TSC-related refractory epilepsy, which can help us better select patients with TSC-related refractory epilepsy who are suitable for SEEG placement.