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 electrophysiology, seizure symptomatology, multimodal imaging characteristics and epileptogenic zone location of the temporal -parietal -occipital junction (TPOJ) epilepsy.MethodsThe seizure symptomatology, head MRI, PET-CT and their fusion manifestations, long-range scalp video EEG monitoring results of 6 cases of TPOJ epilepsy patients from March 2015 to August 2018 were analyzed retrospectively in the Second Hospital of Lanzhou University, and the value of localization of epileptogenic zone was analyzed, and the role of multi-modal evaluation based on SEEG in localization of epileptogenic zone was discussed.ResultsThe first symptoms: 2 of 6 patients were complicated visual hallucination; 3 were head eye deflection (2 were opposite to epileptogenic focus, 1 was ipsilateral); 1 was excessive movement. EEG of scalp: the epileptogenic potentials in intermittent period were all multi -brain regions, but could be lateralized; in seizure period, the electroencephalogram was diffuse in 4 cases, without lateralization, and could be lateralized in 2 cases (1 case was the beginning of one hemisphere, 1 case was the beginning of one posterior head). Imaging findings: MRI was negative in 2 cases, post-traumatic soft focus in 2 cases, and FCD in 2 cases; after fusion of MRI and PET-CT, low metabolic areas in a large area including TPOJ could be found. Six patients were implanted with stereotactic electrodes, and the epileptogenic focus could be identified by EEG monitoring after implantation.ConclusionFor TPOJ epilepsy, the manifestations of premonitory and multimodal images at the onset of seizure can provide important clues for the lateralition of epileptogenic zone; scalp EEG and the first symptoms except premonitory can only provide reference clues; multimodal evaluation based on stereoelectroencephalogram can accurately locate the onset of seizure.
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.
Epilepsy is one of the most common neurological disorders, and surgical intervention is usually used for drug-resistant focal epilepsy. Cortical electrical stimulation is widely used in preoperative evaluation of epilepsy to explore the anatomical-clinical electrical correlations between epileptogenic and functional networks through electrical stimulation, and the functional brain maps produced by cortical electrical stimulation depict areas of the functional cortex at an individual level, identifying the functional cortex with greater precision, as well as helping to establish epilepsy network, enabling more precise localization of seizure zones and providing a more accurate localization for surgical resection. Electrical cortical stimulation has become a standard technique for the preoperative assessment of brain region function in brain surgery. It is an indispensable part of preoperative evaluation.The main types of functional mapping by electrical stimulation include stereoelectroencephalography (SEEG) and subdural electrode (SDE), SEEG-guided cortical electrical stimulation is gradually becoming more mainstream compared to subdural electrodes, and is increasingly valuable and important as a preoperative evaluation of epilepsy. It is increasingly demonstrating its value and importance because it avoids craniotomy, takes less time for surgery, has fewer associated complications and infections, and can explore deep lesions, increasing the understanding of human functional neuroanatomy and enabling more precise localization of seizure zones.This article reviews the history of the development of cortical electrical stimulation technology, the intrinsic mechanisms, the value of the application of SEEG, and also provides a comprehensive comparison between SEEG and SDE, despite the irreplaceable advantages of SEEG, attention should be paid to the unresolved clinical and scientific issues of SEEG, and the establishment of a consensus-based clinical guideline, as the application of this technology will be more widely used in both clinical and scientific work.
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.
Objective To research clinical manifestations, electrophysiological characteristics of epileptic seizures arising from diagonal sulci (DS), to improve the level of the diagnosis and treatment of frontal epilepsy. MethodsWe reviewed all the patients underwent a detailed presurgical evaluation, including 5 patients with seizures to be proved originating from diagonal sulci by Stereo-electroencephalography (SEEG). All the 5 patients with detailed medical history, head Magnetic resonance (MRI), the Positron emission computered tomography (PET-CT) and psychological evaluation, habitual seizures were recorded by Video-electroencephalography (VEEG) and SEEG, we review the intermittent VEEG and ictal VEEG, analyzing the symptoms of seizures. Results 5 patients were divided into 2 groups by SEEG, group 1 including 3 patients with seizures arising from the bottom of DS, group 2 including 2 patients with seizures arising from the surface of DS, all the tow groups with seizures characterized by both having tonic and complex motors, tonic seizures were prominent in seizures from left DS, and tonic seizures may absent in seizures from right DS. Intermittent discharges with group1 were diffused, and intermittent discharges with group 2 were focal, but both brain areas of frontal and temporal were infected. Ictal EEG findings were consistent with the characteristics of neocortical seizures, the onset EEG shows voltage attenuation, seizures from bottom of DS with diffused EEG onset, and seizures from surface of DS with more focal EEG onset, but both frontal and anterior temporal regions were involved. Conclusionthe symptom of seizures arising from DS characterized by tonic and complex motor, can be divided into seizures arising from the bottom of DS and seizures from the surface of DS, with different electrophysiological characters.