Objectives: Low-grade tumors are the most common neoplasms inducing focal epilepsy; however, the short-and medium-term efficacy of surgery in epilepsy patients with low-grade tumors remains underappreciated. This study aims to summarize the clinical characteristics of epilepsy patients with low-grade tumors and to identify factors associated with postsurgical seizure-free outcomes. Methods: We retrospectively reviewed consecutive patients with lowgrade tumors who underwent subsequent epilepsy surgery in our epilepsy center, between 2012 and 2018 with a minimum follow-up of 1 year. Using Engel's classification and Kaplan-Meier survival analysis, we assessed postoperative seizure freedom over time. Demographical, electroclinical, and other presurgical evaluations were then evaluated for association with postoperative seizure outcome. Results: The cohort included a total of 132 patients: 79 males and 53 females. Among them, 110 (83.33%) were seizure-free through their last followup. The Engel class I outcomes were 90.15%, 87.76%, 85.53%, 82.46%, and 73.17% at the end of the 1st, 2nd, 3rd, 4th, and 5th postoperative years, respectively. Multivariate logistic analysis revealed that longer epilepsy duration (p < 0.001, OR 1.091, 95% CI 1.040-1.144) and incomplete resection (p = 0.009, OR 3.673, 95% CI 1.393-9.684) were independently associated with seizure recurrence through the last follow-up. Conclusions: Surgical treatment for seizure control in patients with low-grade tumors provides excellent shortand median-term outcomes.

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Objective Sleep strongly activates interictal epileptic activity through an unclear mechanism. We investigated how scalp sleep slow waves (SSWs), whose positive and negative half‐waves reflect the fluctuation of neuronal excitability between the up and down states, respectively, modulate interictal epileptic events in focal epilepsy. Methods Simultaneous polysomnography was performed in 45 patients with drug‐resistant focal epilepsy during intracranial electroencephalographic recording. Scalp SSWs and intracranial spikes and ripples (80–250 Hz) were detected; ripples were classified as type I (co‐occurring with spikes) or type II (occurring alone). The Hilbert transform was used to analyze the distributions of spikes and ripples in the phases of SSWs. Results Thirty patients with discrete seizure‐onset zone (SOZ) and discernable sleep architecture were included. Intracranial spikes and ripples accumulated around the negative peaks of SSWs and increased with SSW amplitude. Phase analysis revealed that spikes and both ripple subtypes in SOZ were similarly facilitated by SSWs exclusively during down state. In exclusively irritative zones outside SOZ (EIZ), SSWs facilitated spikes and type I ripples across a wider range of phases and to a greater extent than those in SOZ. The type II and type I ripples in EIZ were modulated by SSWs in different patterns. Ripples in normal zones decreased specifically during the up‐to‐down transition and then increased after the negative peak of SSW, with a characteristically high post‐/pre‐negative peak ratio. Significance SSWs modulate interictal events in an amplitude‐dependent and region‐specific pattern. Pathological ripples and spikes were facilitated predominantly during the cortical down state. Coupling analysis of SSWs could improve the discrimination of pathological and physiological ripples and facilitate seizure localization.

OBJECTIVE The authors investigated alterations in functional connectivity (FC) and EEG power during ictal onset patterns of low-voltage fast activity (LVFA) in drug-resistant focal epilepsy. They hypothesized that such changes would be useful to classify epilepsy surgical outcomes. METHODS In a cohort of 79 patients with drug-resistant focal epilepsy who underwent stereoelectroencephalography (SEEG) evaluation as well as resective surgery, FC changes during the peri-LVFA period were measured using nonlinear regression (h2) and power spectral properties within/between three regions: the seizure onset zone (SOZ), early propagation zone (PZ), and noninvolved zone (NIZ). Desynchronization and power desynchronization h2 indices were calculated to assess the degree of EEG desynchronization during LVFA. Multivariate logistic regression was employed to control for confounding factors. Finally, receiver operating characteristic curves were generated to evaluate the performance of desynchronization indices in predicting surgical outcome. RESULTS Fifty-three patients showed ictal LVFA and distinct zones of the SOZ, PZ, and NIZ. Among them, 39 patients (73.6%) achieved seizure freedom by the final follow-up. EEG desynchronization, measured by h2 analysis, was found in the seizure-free group during LVFA: FC decreased within the SOZ and between regions compared with the pre-LVFA and post-LVFA periods. In contrast, the non–seizure-free group showed no prominent EEG desynchronization. The h2 desynchronization index, but not the power desynchronization index, enabled classification of seizure-free versus non–seizure-free patients after resective surgery. CONCLUSIONS EEG desynchronization during the peri-LVFA period, measured by within-zone and between-zone h2 analysis, may be helpful for identifying patients with favorable postsurgical outcomes and also may potentially improve epileptogenic zone identification in the future.

Introduction The aim was to evaluate the clinical characteristics and prognostic significance of subclinical seizures (SCSs) on scalp video-electroencephalogram (VEEG) monitoring with or without intracranial electroencephalogram (IEEG) monitoring in patients who had epilepsy surgery. Methods We reviewed 286 epileptic patients who underwent subsequent epilepsy surgery during scalp-VEEG evaluation with or without IEEG monitoring between 2013 and 2020, with a minimum follow-up of 1 year. The prevalence and clinical characteristics of SCSs, as well as their prognostic significance, were analyzed. Results A total of 286 patients were enrolled for analysis, and 80 patients had IEEG implanted. SCSs were recorded in 9.79% of the patients based on VEEG and 50% based on IEEG. In the VEEG group ( n = 286), younger seizure onset ( P = 0.004) was associated with the presence of s-SCSs (SCSs detected on scalp VEEG). In the IEEG group ( n = 80), temporal lobe epilepsy ( P = 0.015) was associated with the presence of i-SCSs (SCSs detected on IEEG). Of 286 patients, 208 (72.73%) were seizure-free in the VEEG group, and 56 0f 80 patients (70%) were seizure-free in the IEEG group through the last follow-up. In the VEEG group, the presence of s-SCSs did not affect seizure outcome; predictors of seizure recurrence were longer epilepsy duration ( P = 0.003, OR 1.003, 95% CI 1.001–1.005), history of focal to bilateral tonic–clonic seizure ( P = 0.027, OR 1.665, 95% CI 1.060–2.613), nonspecific pathology ( P = 0.018, OR 2.184, 95% CI 1.145–4.163), and incomplete resection ( P = 0.004, OR 2.705, 95% CI 1.372–5.332). In the IEEG group, i-SCSs were significantly associated with seizure outcome ( P = 0.028, OR 0.371, 95% CI 0.153–0.898). Conclusion The rate of SCSs captured on IEEG monitoring was higher than that on VEEG monitoring during presurgical evaluation. SCSs detected on VEEG monitoring were associated with younger seizure onset. SCSs detected on IEEG monitoring were associated with temporal lobe epilepsy and also predicted surgical outcomes in focal epilepsy. Supplementary Information The online version contains supplementary material available at 10.1007/s40120-022-00342-y.