Background: Different methods for intracranial electrode recording have various advantages and disadvantages, and controversy exists regarding the complications of stereoelectroencephalography (SEEG) and subdural EEG. Objective: The purpose of this study was to determine the efficacy and safety of SEEG by comparing it with subdural EEG. Methods: Data from 100 patients who underwent SEEG (n = 48) and subdural EEG (n = 52) to evaluate the epileptogenic zone were collected from June 2011 to June 2015. The evaluation results, surgical outcomes, and complications were compared. Results: No significant differences were noted between the SEEG and subdural EEG groups in identifying the epileptogenic zone or undergoing epileptic surgery. Of the 88 patients who underwent epilepsy surgery after assessment, 59.5% in the SEEG group and 52.2% in the subdural EEG group became seizure free. No significant differences in postoperative seizure control or intelligence improvement were noted. The overall complication rate in SEEG patients (8/48; 16.7%) was lower than that in subdural EEG patients (13/52; 25%), particularly for hemorrhage and infection (4.2 vs. 17.3%, p < 0.05). Conclusions: This retrospective review indicates that SEEG has low associated complications, particularly regarding hemorrhage and infection. SEEG is a safe and effective method for intracranial monitoring.

Focal cortical dysplasia type IIb (FCDIIb) and tuberous sclerosis complex (TSC) are typical causes of developmental delay and refractory epilepsy. G-protein-coupled receptor 30 (GPR30) is a specific estrogen receptor that is critical in neurodevelopment, neuroinflammation, and neuronal excitability, suggesting that it plays a potential role in the epilepsy of patients with FCDIIb and TSC. Therefore, we investigated the role of GPR30 in patients with FCDIIb and TSC. We found that the expression of GPR30 and its downstream protein kinase A (PKA) pathway were decreased and negatively correlated with seizure frequency in female patients with FCDIIb and TSC, but not in male patients. GPR30 was widely distributed in neurons, astrocytes, and microglia, and its downregulation was especially notable in microglia. The GPR30 agonist G-1 increased the expression of PKA and p-PKA in cultured cortical neurons, and the GPR30 antagonist G-15 exhibited the opposite effects of G-1. The NF-κB signaling pathway was also activated in the specimens of female patients with FCDIIb and TSC, and was regulated by G-1 and G-15 in cultured cortical neurons. We also found that GPR30 regulated cortical neuronal excitability by altering the frequency of spontaneous excitatory postsynaptic currents and the expression of NR2A/B. Further, the relationship between GPR30 and glycometabolism was evaluated by analyzing the correlations between GPR30 and 18 F-FDG PET-CT values (standardized uptake values, SUVs). Positive correlations between GPR30 and SUVs were found in female patients, but not in male patients. Intriguingly, GPR30 expression and SUVs were significantly decreased in the epileptogenic tubers of female TSC patients, and ROC curves indicated that SUVs could predict the localization of epileptogenic tubers. Taken together, our results suggest a potential protective effect of GPR30 in the epileptogenesis of female patients with FCDIIb and TSC. | 347 GPR30 EXPRESSION IN THE EPILEPTOGENIC FOCI K E Y W O R D S 18 F-FDG Positron emission tomography-computerized tomography, focal cortical dysplasia type IIb, G-protein-coupled receptor 30, standardized uptake values, tuberous sclerosis complex, whole-cell patch-clamp

Previously, depth electrode implantation was usually performed using the frame-based stereotactic method (14). The frame-based stereotactic system has high positioning precision, and is suitable for precise positioning and puncturing towards deep structures; for example in stereotactic biopsy or deep brain stimulation (DBS), which need accurate positioning (3, 6). The disadvantages of this method, however, are evident: 1) The puncturing process is complicated and time consuming, making it difficult to implant multiple electrodes (e.g. for stereoelectroencephalography [SEEG]) (16); 2) It is difficult to adjust the puncture direction and path in real-time, especially from a poor posture (16); 3) The puncturing process might injure blood vessels and other vital structures, causing █ INTRODUCTION Intracranial electrode tracing has become an important means for evaluating the epileptogenic focus, especially in patients whose epileptogenic loci cannot be located using electroencephalography and other non-invasive assessment tools. Invasive intracranial electroencephalography (iEEG) is the preferred means of determining the exact locations of epileptogenic foci (12, 21). Intracranial electrodes can be classified as epidural, subdural cortical (including strip-like and grid-like electrode), and depth electrodes, of which the depth electrode has been widely used in epilepsy surgery, and plays an important role in the epileptogenic focus evaluation of the medial temporal lobe (2, 21). AIM:To investigate the application of neuronavigation in the implantation of depth electrodes in patients with epilepsy. MATERIAL and METHODS:Thirty-six patients with epilepsy who were implanted with depth electrodes using neuronavigation were assessed for accuracy of implantation and associated complications. RESULTS:In the imaging navigation group, patients were implanted with 2-14 depth electrodes. The average number of implantations was 4.8 electrodes/case. The average implantation error was 2.03 ± 0.98 mm, exhibiting no significant difference compared to the frame-based stereotactic group. In the imaging group, an average of 19.4 min was required to implant each electrode, which was significantly shorter than the time required in the frame group (34.5 min). The temporal lobe was elucidated as the factor that affects electrode implantation accuracy. One patient in the imaging group exhibited a small amount of bleeding, and one suffered from cerebrospinal fluid leakage; however, the overall complication rate in the imaging group was lower than that in the frame group. CONCLUSION:Imaging navigation provides better means of depth electrode implantation; its implantation accuracy is similar to that of the frame-based stereotactic method and it is less time consuming and causes less complications, and is especially suitable for stereoelectroencephalography, which requires multiple depth electrodes.

Background: Temporal lobe epilepsy (TLE) is the most common intractable epilepsy in adults, and elucidation of the underlying pathological mechanisms is needed. Voltage-gated chloride channels (ClC) play diverse physiological roles in neurons. However, less is known regarding their functions in the epilepogenesis of TLE. Methods: ClC-mediated current and the spontaneous inhibitory synaptic currents (sIPSC) in hippocampal neurons of epileptic lesions were investigated by electrophysiological recording. The EEG data were analyzed by Z-scored wavelet and Fourier transformations. The expression of ClC-3, a member of ClC gene family, was detected by immunostaining and western blot. Findings: ClC-mediated current was increased in the hippocampal neurons of chronic TLE mice. Application of chloride channel blockers, NPPB (5-Nitro-2-[3-phenylpropylamino] benzoic acid) and DIDS (4,4'-Diisothiocyanato-2,2'-stilbenedisulfonic acid disodium salt) reduced ClC-mediated current and increased inhibitory synaptic transmission in TLE mice. NPPB and DIDS reduced the seizure frequency and the average absolute power of ictal high-frequency oscillations (HFOs, 80-500 Hz) in TLE mice. In addition, both drugs induced outwardly rectified currents, which might be tonic inhibitory currents in the hippocampal neurons of TLE patients. Furthermore, the expression of ClC-3 was increased in the hippocampus of TLE mice and patients and positively correlated with both the absolute power and number of ictal HFOs per seizure in the sclerotic hippocampus. Interpretation: These data suggest that ClC participate in the epilepogenetic process of TLE and the inhibition of ClC may have anti-epileptic effect.

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Objective. Tuberous sclerosis complex (TSC) is a rare neurodevelopmental disorder often associated with intractable epilepsy, and surgical resection is the effective therapeutic approach to alleviate seizures in TSC patients. Scalp electroencephalogram (EEG) is a noninvasive method used to diagnose epilepsy; however, the relationship between scalp video-EEG findings and postsurgical seizure outcomes has not been fully evaluated in TSC patients. Materials and Methods. The relationship between clinical characteristics and seizure outcomes of TSC patients with 1-year, 5-year, and 10-year follow-ups was retrospectively analyzed. We explored the association of interictal epileptiform discharges (IEDs) with postsurgical seizure outcomes. Further, the differences in clinical characteristics among four IED patterns (focal, lateralized, multifocal, and generalized IEDs) were assessed. Results. A total of 82 patients were enrolled in this study. There were 82 patients with 1-year follow-up, 75 patients with 5-year follow-up, and 57 patients with 10-year follow-up, and the IEDs were associated with the postsurgical outcomes. Patients with focal, lateralized, and generalized IEDs had seizure freedom (SF) in 1-year follow-up, respectively. Intriguingly, patients with lateralized IEDs had long-term SF in 5-year and 10-year follow-ups. Conclusions. A significant association existed between IEDs and long-term postsurgical outcomes in TSC patients. TSC patients with lateralized IEDs often showed long-term SF and mild clinical epileptic characteristics. According to our study, IEDs may guide clinical care for TSC patients with intractable epilepsy.