Stereo-electroencephalography (SEEG) is widely used to record the electrical activity of patients' brain in clinical. The SEEG-based epileptogenic network can better describe the origin and the spreading of seizures, which makes it an important measure to localize epileptogenic zone (EZ). SEEG data from six patients with refractory epilepsy are used in this study. Five of them are with temporal lobe epilepsy, and the other is with extratemporal lobe epilepsy. The node outflow (out-degree) and inflow (in-degree) of information are calculated in each node of epileptic network, and the overlay between selected nodes and resected nodes is analyzed. In this study, SEEG data is transformed to bipolar montage, and then the epileptic network is established by using independent effective coherence (iCoh) method. The SEEG segments at onset, middle and termination of seizures in Delta, Theta, Alpha, Beta, and Gamma rhythms are used respectively. Finally, the K-means clustering algorithm is applied on the node values of out-degree and in-degree respectively. The nodes in the cluster with high value are compared with the resected regions. The final results show that the accuracy of selected nodes in resected region in the Delta, Alpha and Beta rhythm are 0.90, 0.88 and 0.89 based on out-degree values in temporal lobe epilepsy patients respectively, while the in-degree values cannot differentiate them. In contrast, the out-degree values are higher outside the temporal lobe in the patient with extratemporal lobe epilepsy. Based on the out-degree feature in low-frequency epileptic network, this study provides a potential quantitative measure for identifying patients with temporal lobe epilepsy in clinical.
ObjectiveTo explore the clinical features and EEG features of gelastic seizures, and analyze its value of lateral localization of epileptogenic area. MethodsAll patients with gelastic seizures admitted to the Sanbo Brain Hospital of Capital Medical University between January 2014 and December 2023 were reviewed and analyzed for history, symptomatology, imaging, electroencephalographic features and surgical protocols in patients who met the inclusion criteria and were followed up for at least 1 year, and surgical efficacy was assessed by using the Engel grading. ResultsA total of 51 patients with gelastic seizures were included, there were 32 (62.75%) males and 19 (37.25%) females, 21 (41.18%) with hypothalamic hamartomas (HH) and 30 (58.82%) with non-hypothalamic hamartomas. The age of onset was earlier in the HH group than in the non-HH group, with a median age of onset of 24.00 (0.00 ~ 96.00) and 78.00 (1.00 ~ 396.00) months (P<0.001). There are three types of laughter according to their characteristics: smiling or pleasant expressions, laughing out loud, crying or bitter laughter, with smiling or pleasant expressions being the most common (49.02%). Simple laughter is rare in all patients and is often accompanied by other manifestations such as autonomic symptoms, automatic movements, complex movements, and tonic seizures. Most of the HH group started with laughter whereas in the non-HH group laughter appeared mostly in the mid to late stages (P=0.007). Most of the HH group (57.14%) had preserved consciousness whereas most of the non-HH group (83.33%) had loss of consciousness (P=0.003). The interictal discharges in the HH group were mostly diffuse or multiregional, whereas those in the non-HH group were mostly regional (P=0.035). The onset of EEG during the seizure period in the HH group was mostly diffuse, whereas those in the non-HH group were mostly regional, mainly in the frontal and temporal regions, but there was no significant difference between the two groups (P=0.148). The non-HH group was mostly seen in those with definite lesions, and the most common type of lesion was FCD (focal cortical dysplasia, FCD). All patients enrolled in the group underwent surgical treatment, and stereoelectroencephalogram (SEEG) electrode implantation was performed in 13 cases in the HH group and in 17 cases in the non-HH group. 61.90% of the patients in the HH group had an Engel grade I, and 73.33% of the patients in the non-HH group had an Engel grade I. ConclusionsGelastic seizures has a complex neural network, with common causes other than hypothalamic hamartomas, and is most commonly seen in frontal or temporal lobe epilepsy, as well as in the insula or parietal lobe, with the most common type of lesion being FCD. The symptomatology, stage of onset, and electroencephalographic features of gelastic seizures can help in the differential diagnosis, and SEEG can help define the origin of the seizure and its diffusion pathway. The overall prognosis of surgical treatment was better in both the hypothalamic hamartomas and non-hypothalamic hamartomas groups.
ObjectiveTo explore the advantages and disadvantages of using two intracranial EEG (iEEG) monitoring methods—Subdural ectrodes electroencephalography (SDEG)and Stereoelectroencephalography (SEEG), in patients with “difficult to locate” Intractable Epilepsy. MethodsRetrospectively analyzed the data of 60 patients with SDEG monitoring (49 cases) and SEEG monitoring (11 cases) from January 2010 to December 2018 in the Department of Neurosurgery of the First Affiliated Hospital of Fujian Medical. Observe and statistically compare the differences in the evaluation results of epileptic zones, surgical efficacy and related complications of the two groups of patients, and review the relevant literature. ResultsThe results showed that the two groups of SDEG and SEEG had no significant difference in the positive rate and surgical resection rate of epileptogenic zones, but the bilateral implantation rate of SEEG (5/11, 45.5%) was higher than that of SDEG (18/49, 36.7%). At present, there was no significant difference in the postoperative outcome among patients with epileptic zones resected after SDEG and SEEG monitoring (P>0.05). However, due to the limitation of the number of SEEG cases, it is not yet possible to conclude that the two effects were the same. There was a statistically significant difference in the total incidence of serious complications of bleeding or infection between the two groups (SDEG 20 cases vs. SEEG 1 case, P<0.05). There was a statistically significant difference in the total incidence of significant headache or cerebral edema between the two groups (SDEG 26 cases vs. SEEG 2 cases, P<0.05). There was a statistically significant difference in the incidence of cerebrospinal fluid leakage, subcutaneous fluid incision, and poor healing of incision after epileptic resection (SDEG 14 cases vs. SEEG 0 case, P<0.05); there were no significant differences in dysfunction of speech, muscle strength between the two groups (P>0.05). ConclusionSEEG has fewer complications than SDEG, SEEG is safer than SDEG. The two kinds of iEEG monitoring methods have advantages in the localization of epileptogenic zones and the differentiation of functional areas. The effective combination of the two methods in the future may be more conducive to the location of epileptic zones and functional areas.
For refractory epilepsy requiring surgical treatment in clinic, precise preoperative positioning of the epileptogenic zone is the key to improving the success rate of clinical surgical treatment. Although the use of electrical stimulation to locate epileptogenic zone has been widely carried out in many medical centers, the preoperative implantation evaluation of stereoelectroencephalography (SEEG) and the interpretation of electrical stimulation induced EEG activity are still not perfect and rigorous. Especially, there are still technological limitations and unknown areas regarding electrode implantation mode, stimulation parameters design, and surgical prognosis correlation. In this paper, the clinical background, application status, technical progress and development trend of SEEG-based stereo-electric stimulation-induced cerebral electrical activity in the evaluation of refractory epilepsy are reviewed, and applications of this technology in clinical epileptogenic zone localization and cerebral cortical function evaluation are emphatically discussed. Additionally, the safety during both of high-frequency and low-frequency electrical stimulations which are commonly used in clinical evaluation of refractory epilepsy are also discussed.
ObjectiveTo study the therapeutic efficacy of stereoelectroencephalography (SEEG)-guided radiofrequency thermo-coagulation ablation (RF-TC) in the treatment of tuberous sclerosis (TSC) related epilepsy and to investigate the prediction of the therapeutic response to SEEG-guided RF-TC for the efficacy of the subsequent surgical treatment. MethodsWe retrospectively analyze TSC patients who underwent SEEG phase II evaluation from January 2014 to January 2023, and to select patients who underwent RF-TC after completion of SEEG monitoring, study the seizure control of patients after RF-TC, and classify patients into effective and ineffective groups for RF-TC treatment according to the results of RF-TC treatment, compare the surgical outcomes of patients in the two groups after SEEG, to explore the prediction of surgical outcome by RF-TC treatment. Results59 patients with TSC were enrolled, 53 patients (89.83%) were genetic detection, of which 28 (52.83%) were TSC1-positive, 21 (39.62%) were TSC2-positive, and 4 (7.54%) were negative, with 33 (67.34%) de novo mutations. The side of the SEEG electrode placement: left hemisphere in 9 cases, right hemisphere in 13 cases, and bilateral hemisphere in 37 cases. 37 patients (62.71%) were seizure-free at 3 months, 31 patients (52.54%) were seizure-free at 6 months, 29 patients (49.15%) were seizure-free at 12 months, and 20 patients (39.21%) were seizure-free at 24 months or more. 11 patients had a seizure reduction of more than 75% after RF-TC, and the remaining 11 patients showed no significant change after RF-TC. There were 48 patients (81.35%) in the effective group and 11 patients (18.65%) in the ineffective group. In the effective group, 22 patients were performed focal tuber resection laser ablation, 19 cases were seizure-free (86.36%). In the ineffective group, 10 patients were performed focal tuber resection laser ablation, only 5 cases were seizure-free (50%), which was a significant difference between the two groups (P<0.05). ConclusionsOur data suggest that SEEG guided RF-TC is a safe and effective both diagnostic and therapeutic treatment for TSC-related epilepsy, and can assist in guiding the development of future resective surgical strategies and determining prognosis.
ObjectivesPost-encephalitic epilepsy could be of great chance of pharmaco-resistant, even surgery may not achieve seizure free. The aim of this study is to mapping epileptogenic area of pharmaco-resistant post-encephalitic temporal lobe epilepsy, to find whether "temporal plus" epilepsy is the main type and its surgery outcome, based on stereo-EEG(SEEG) study.MethodWe retrospectively studied 15 patients with pharmaco-resistant temporal lobe epilepsy. Scalp EEG, seizure semiology, MRI, FDG-PET, and SEEG were reviewed for all patients. According to epileptogenic area which was analysed by SEEG, 15 patients were divided into 2 groups, temporal lobe epilepsy(TLE) group and temporal plus epilepsy(TPE) group. Clinical characteristics were compared with each group, by t-test or Fisher exact test when data needed.ResultsThere were 8 patients in TLE group, with 6 mesial TLE, 1 lateral TLE, 1 mesial-lateral TLE. And 7 patients in TPE group. Age of seizure onset (P=0.548), duration of epilepsy (P=0.099), age of remote encephalitis (P=0.385), type of semiology (P=0.315) and lateralization of MR lesions (P=1.000), interictal FDG-PET hypometabalism (P=1.000) or intracranial implantation (P=0.619) were of no statistically difference between TLE group and TPE group. Surgery was performed in all patients. Better outcome was obtained in TLE group(5/8 class Ⅰ), and poor was in TPE group(3/7class Ⅰ).ConclusionMesial-TLE and temporal plus epilepsy were common types of pharmaco-resistant post-encephalitic TLE. There was no way to differentiate clinically, except by SEEG. Mesial-TLE had a better outcome after surgery, but temporal plus epilepsy did not.