Functional profile of perilesional gray matter in focal cortical dysplasia: an fMRI study.

Objectives: We aim to investigate the functional profiles of perilesional gray matter (GM) in epileptic patients with focal cortical dysplasia (FCD) and to correlate these profiles with FCD II subtypes, surgical outcomes, and different antiseizure medications (ASMs) treatment response patterns. Methods: Nine patients with drug-responsive epilepsy and 30 patients with drug-resistant epilepsy (11 were histologically confirmed FCD type IIa, 19 were FCD type IIb) were included. Individual-specific perilesional GM and contralateral homotopic GM layer masks were generated. These masks underwent a two-voxel (2 mm) dilation from the FCD lesion and contralateral homotopic region, resulting in 10 GM layers (20 mm). Layer 1, the innermost, progressed to Layer 10, the outermost. Amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) analyses were conducted to assess the functional characteristics of ipsilateral perilesional GM and contralateral homotopic GM. Results: Compared to the contralateral homotopic GM, a significant reduction of ALFF was detected at ipsilateral perilesional GM layer 1 to 6 in FCD type IIa (after Bonferroni correction p < 0.005, paired t-test), whereas a significant decrease was observed at ipsilateral perilesional GM layer 1 to 2 in FCD type IIb (after Bonferroni correction p < 0.005, paired t-test). Additionally, a significant decrease of the ReHo was detected at ipsilateral perilesional GM layer 1 compared to the CHRs in FCD type IIb. Notably, complete resection of functional perilesional GM alterations did not correlate with surgical outcomes. Compared to the contralateral homotopic GM, a decreased ALFF in the ipsilateral perilesional GM layer was detected in drug-responsive patients, whereas decreased ALFF in the ipsilateral perilesional GM layer 1-6 and decreased ReHo at ipsilateral perilesional GM layer 1 were observed in drug-resistant patients (after Bonferroni correction p < 0.005, paired t-test). Conclusion: Our findings indicate distinct functional profiles of perilesional GM based on FCD histological subtypes and ASMs' response patterns. Importantly, our study illustrates that the identified functional alterations in perilesional GM may not provide sufficient evidence to determine the epileptogenic boundary required for surgical resection.

Predictors and prevalence of COVID-19 vaccination in patients with focal epilepsy following resection surgery.

BACKGROUND AND PURPOSE: In light of the ongoing COVID-19 pandemic, vaccination has emerged as the primary and most effective solution. The aim of this study was to examine compliance rates of vaccination and explore the factors that predict vaccine uptake among patients with epilepsy (PWE) who have undergone resection surgery. METHOD: To examine the variations in vaccination coverage, safety concerns, and factors influencing vaccination hesitancy among PWE who have undergone resection surgery, this study recruited patients with at least one-year follow-up. We utilized questionnaires to gather clinical characteristics and obtain information regarding COVID-19 vaccines. RESULTS: Among the 303 patients included in the study, a majority of 229 (75.58%) achieved a seizure-free outcome (Engel Ia). Of these patients, 178 (58.75%) received at least one dose of COVID-19 vaccine, and the vaccination rate has remained relatively consistent over the past six months. Nearly 94.95% of those who received the vaccine completed the full vaccination regimen, with the majority (n = 174, 97.75%) opting for an inactivated vaccine. Only three patients reported side effects unrelated to epilepsy, and one patient experienced a worsening of typical aura seizures within one month after vaccination. Notably, significant positive associations were observed between COVID-19 vaccine acceptance and adulthood (age 18 years or older) (OR = 1.820, 95% CI = 1.018-3.252, p = 0.043) as well as achieving a seizure-free outcome (OR = 2.823, 95% CI = 1.619-4.921, p < 0.001). Regarding the unvaccinated patients, approximately one-fifth expressed willingness to receive a future COVID-19 vaccine, while the remainder were hesitant (41.60%) or unsure (39.20%) about vaccination. These reservations mainly stemmed from concerns about the potential worsening of seizures and vaccine safety. CONCLUSIONS: Inactivated vaccines can be considered safe for individuals with epilepsy who have undergone resection surgery. The likelihood of being vaccinated was found to be comparatively higher among the cohort with seizure-free status or adults. To promote COVID-19 vaccination among children, it is crucial to implement comprehensive education and public awareness campaigns that emphasize the safety of vaccines. These efforts will help encourage widespread acceptance of vaccination and ensure the well-being of individuals with epilepsy.

Pre-ictal fluctuation of EEG functional connectivity discriminates seizure phenotypes in mesial temporal lobe epilepsy.

OBJECTIVE: We explored whether quantifiable differences between clinical seizures (CSs) and subclinical seizures (SCSs) occur in the pre-ictal state. METHODS: We analyzed pre-ictal stereo-electroencephalography (SEEG) retrospectively across mesial temporal lobe epilepsy patients with recorded CSs and SCSs. Power spectral density and functional connectivity (FC) were quantified within and between the seizure onset zone (SOZ) and the early propagation zone (PZ), respectively. To evaluate the fluctuation of neural connectivity, FC variability was computed. Measures were further verified by a logistic regression model to evaluate their classification potentiality through the area under the receiver-operating-characteristics curve (AUC). RESULTS: Fifty-four pre-ictal SEEG epochs (27 CSs and 27 SCSs) were selected among 14 patients. Within the SOZ, pre-ictal FC variability of CSs was larger than SCSs in 1-45 Hz during 30 seconds before seizure onset. Pre-ictal FC variability between the SOZ and PZ was larger in SCSs than CSs in 55-80 Hz within 1 minute before onset. Using these two variables, the logistic regression model achieved an AUC of 0.79 when classifying CSs and SCSs. CONCLUSIONS: Pre-ictal FC variability within/between epileptic zones, not signal power or FC value, distinguished SCSs from CSs. SIGNIFICANCE: Pre-ictal epileptic network stability possibly marks seizure phenotypes, contributing insights into ictogenesis and potentially helping seizure prediction.

COVID-19 vaccination hesitancy and safety among adult people with epilepsy in eastern China.

OBJECTIVE: This study assesses the hesitancy and safety of vaccination administration for the novel 2019 Coronavirus Disease (COVID-19) among adult people with epilepsy (PWE). METHODS: We recruited adult PWE who visited the outpatient epilepsy clinic from August 2021 to February 2022. We administered a structured questionnaire and a face-to-face interview regarding demographic factors, epilepsy characteristics, and relevant vaccine issues to all patients. Factors related to receiving a vaccine and epilepsy-related events after vaccination were then analyzed. RESULTS: A total of 501 PWE were surveyed; 288 were unvaccinated and 213 were vaccinated. Patients without jobs (OR: 0.59; 95% CI: 0.37-0.95, p = 0.03) were less likely to receive the vaccine compared to students or those with jobs. Other factors associated with vaccination were a higher number of anti-seizure medications (OR: 0.72; 95% CI: 0.55-0.95, p = 0.02) and a lower pre-vaccine seizure frequency (OR: 2.21; 95% CI: 1.06-4.59, p = 0.03). Of the 213 vaccinated patients, 10 (4.70%) reported at least one local and/or systemic side effect. Most patients (92.50%) did not report worse seizures within one month of vaccination. Poor ASM adherence (OR: 15.06; 95% CI: 1.75-129.87, p = 0.01) and fatigue/stimulant drinks such as caffeine (OR: 50.59; 95% CI: 7.57-337.94, p < 0.01) were significantly associated with seizure worsening within one month of receiving the COVID-19 vaccination. CONCLUSION: Almost two-fifths of patients with adult PWE have received a COVID-19 vaccine. Attention should be paid to educating epilepsy patients without jobs on the significance and safety of the vaccine. There was a low risk of seizure worsening in the short term after vaccination in PWE.

Patterns of hypometabolism in frontal lobe epilepsy originating in different frontal regions.

OBJECTIVES: Analysis of FDG-PET imaging commonly shows that hypometabolism extends into extra-epileptogenic zones (extra-EZ). This study investigates the distribution patterns of hypometabolism in frontal lobe epilepsy (FLE) originating in different frontal regions. METHODS: Sixty-four patients with FLE were grouped by EZ localization according to Brodmann areas (BAs): Group 1 (the frontal motor and premotor area), BAs 4, 6, and 8; Group 2 (the inferior frontal gyrus and opercular area), BAs 44, 45, and 47; Group 3 (the dorsal prefrontal area), BAs 9, 10, 11, and 46; and Group 4 (the medial frontal and anterior cingulate gyrus), BAs 32 and 24. Regions of extra-EZ hypometabolism were statistically analyzed between FLE groups and healthy controls. Correlation analysis was performed to identify relationships between the intensity of hypometabolism and clinical characteristics. RESULTS: Significant hypometabolism in the ipsilateral (Groups 1 and 4) or bilateral (Groups 2 and 3) anterior insulae was found. Groups 1 and 4 presented with limited distribution of extra-EZ hypometabolism, whereas Groups 2 and 3 showed widely distributed extra-EZ hypometabolism in the rectus gyrus, cingulate gyrus, and other regions. Additionally, the intensity of hypometabolism was correlated with epilepsy duration in Groups 2 and 3. CONCLUSIONS: All FLE groups showed hypometabolism in the anterior insula. In addition, distinct patterns of extra-EZ hypometabolism were identified for each FLE group. This quantitative FDG-PET analysis expanded our understanding of the topography of epileptic networks and can guide EZ localization in the future.

Focal thalamocortical circuit abnormalities in sleep related epilepsy caused by focal cortical dysplasia type II.

Purpose To investigate the variations of the thalamocortical circuit between the focal cortical dysplasia (FCD) type II patients with sleep-related epilepsy (SRE) and those without SRE (non-SRE). Methods Patients with epilepsy who had histologically proven FCD type II were enrolled. Those without diffusion tensor image and 3-dimensional (3D) T1 MRI sequences were excluded. Thalamocortical structural connectivity to lesion and non-lesion regions was quantified using probabilistic tractography. Fractional anisotropy (FA) and mean diffusivity (MD) were computed. Results A total of 30 consecutive patients were included. Among them, 18 patients (60%) had SRE. Analysis of covariance showed that smaller lesion size was significantly associated with SRE (p=0.048). Compared to patients with non-SRE, patients with SRE showed a significant decrease in FA of thalamocortical projections to the lesion region (p=0.007). No difference was observed in the thalamocortical connectivity to the non-lesion region between patients with SRE and non-SRE. Among the patients with SRE, a significant decrease in FA of thalamocortical projections to the lesion region was noted compared with the contralateral homotopic non-lesion region (p=0.026). Conclusion The data provide evidence of disparity in thalamocortical projections to the lesion regions between SRE and non-SRE. This might indicate the underlying pathophysiology or neuroanatomical substrates of SRE related to the FCD type II.

Clinical Characteristics and Prognostic Significance of Subclinical Seizures in Focal Epilepsy: A Retrospective Study.

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.

Hippocampal Malrotation Could Be Less Significant in Epilepsy Caused by Focal Cortical Dysplasia Type I and Type II.

OBJECTIVES: Debates over the relationship between hippocampal malrotation (HIMAL) and epilepsy continue without consensus. This study explores the role of HIMAL in a cohort of epilepsy caused by focal cortical dysplasia (FCD). METHODS: In this study, 90 patients with epilepsy caused by FCD type I and type II and 48 healthy adults underwent a 3 Tesla MRI following a dedicated epilepsy protocol for the analysis of the prevalence and morphologic features of HIMAL. In addition, numerous clinical characteristics and hippocampal volumes were evaluated. RESULTS: The cohort included a total of 90 patients (32 were HIMAL, 58 were non-HIMAL). Among these patients, 32 (35.6%) had HIMAL (22 left, four right, and six bilateral), which did not differ from the 48 controls, where 16 (33.3%) had HIMAL (12 left, two right, and two bilateral). Neither the quantitative features of HIMAL (diameter ratio, dominant inferior temporal sulcus height ratio, medial distance ratio, dominant inferior temporal sulcus angle, and parahippocampal angle), nor the accompanying characteristics of HIMAL (vertical dominant inferior temporal sulcus, enlarged temporal horn, and a low position of ipsilateral fornix) showed differences between patients with FCD and controls. No statistical difference in the clinical characteristics between FCD patients with HIMAL and those without was found. Neither the side nor the existence of HIMAL was correlated with the lateralization and location of FCD. As to the hippocampal volume, there was no difference between FCD patients with HIMAL and those without. CONCLUSION: Hippocampal malrotation is a common morphologic variant in healthy controls as well as in patients with epilepsy caused by FCD type I and type II. Hippocampal malrotation could be less significant in epilepsy caused by FCD type I and type II.

Focal cortical dysplasia links to sleep-related epilepsy in symptomatic focal epilepsy.

OBJECTIVE: In sleep-related epilepsy (SRE), epileptic seizures predominantly occur during sleep, but the clinical characteristics of SRE remain elusive. We aimed to identify the clinical features associated with the occurrence of SRE in a large cohort of symptomatic focal epilepsy. METHODS: We retrospectively included patients with four etiologies, including focal cortical dysplasia (FCD), low-grade tumors (LGT), temporal lobe epilepsy with hippocampal sclerosis (TLE-HS), and encephalomalacia. SRE was defined as more than 70% of seizures occurring during sleep according to the seizure diary. The correlation between SRE and other clinical variables, such as etiology of epilepsy, pharmacoresistance, seizure frequency, history of bilateral tonic-clonic seizures, and seizure localization was analyzed. RESULTS: A total of 376 patients were included. Among them 95 (25.3%) were classified as SRE and the other 281(74.7%) as non-SRE. The incidence of SRE was 53.5% in the FCD group, which was significantly higher than the other three groups (LGT: 19.0%; TLE-HS: 9.9%; encephalomalacia: 16.7%; P < 0.001). The etiology of FCD (p < 0.001) was significantly associated with SRE (OR: 9.71, 95% CI: 3.35-28.14) as an independent risk factor. In addition, small lesion size (p = 0.009) of FCD further increased the risk of SRE (OR: 3.18, 95% CI: 1.33-7.62) in the FCD group. SIGNIFICANCE: Our data highlight that FCD markedly increased the risk of sleep-related epilepsy independently of seizure localization. A small lesion of FCD further increased the risk of sleep-related epilepsy by 2.18 times in the FCD group.

Response to antiseizure medications in epileptic patients with malformation of cortical development.

BACKGROUND: Malformation of cortical development (MCD) is one of the most common causes of pharmacoresistant epilepsy. Improving the knowledge of antiseizure medications (ASMs) treatment response in epileptic patients with MCD is crucial for optimal treatment options, either pharmacological therapy or non-pharmacological intervention. AIM: To investigate the patterns of medical treatment outcome and the predictors for seizure freedom (SF) with ASM regimens in epilepsy caused by MCD. METHODS: The epileptic patients with MCD were consecutively enrolled from March 2013 to June 2019. SF was defined as no seizures for at least 12 months or three times the longest pretreatment inter-seizure interval, whichever was longer. Outcomes were classified into three patterns: pattern A: patients achieved SF at one point and remained so throughout follow-up; pattern B: patients' seizures fluctuated between periods of SF and relapse; pattern C: SF never attained. The terminal SF was defined if the patients remained SF at the last follow-up visit. RESULTS: A total of 164 epileptic patients with MCD were included. Pattern A was observed in 22, pattern B in 42, and pattern C in 100 patients. SF was ever achieved in 64 (pattern A and B) patients. Twenty-nine patients had terminal SF after a median follow-up time of 4.3 years. With continuing ASM treatment, seizure relapse risk was very low after a 5-year seizure-free period. The pretreatment seizure frequency was the only independent predictor for pattern A and seizure relapse. Sodium channel blockers monotherapy (33.8%) was more effective than levetiracetam (4.5%) in rendering SF in the initial ASM regimen. CONCLUSION: Medical treatment can be successful in a minority of epileptic patients with MCD, and pretreatment seizure frequency helps to predict the treatment outcome. An unequal efficacy of ASMs in epilepsy caused by MCD suggests etiological evaluation is vital in the management of focal epilepsy.

Clinical characteristics of low-grade tumor-related epilepsy and its predictors for surgical outcome.

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 low-grade 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 follow-up. 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 short- and median-term outcomes.

Cortical Excitability in Temporal Lobe Epilepsy with Bilateral Tonic-Clonic Seizures.

OBJECTIVE: We investigated motor cortical excitability (CE) in unilateral temporal lobe epilepsy (TLE) and its relationship to bilateral tonic-clonic seizure (BTCS) using paired-pulse transcranial magnetic stimulation (TMS). METHODS: In this cross-sectional study, we enrolled 46 unilateral TLE patients and 16 age-and sex-matched healthy controls. Resting motor thresholds (RMT); short-interval intracortical inhibition (SICI, GABAA receptor-mediated); facilitation (ICF, glutamatergic-mediated) with interstimulus intervals (ISIs) of 2, 5, 10, and 15 ms; and long-interval intracortical inhibition (LICI, GABAB receptor-mediated) with ISIs of 200-400 ms were measured via paired-pulse TMS. Comparisons were made between controls and patients with TLE, and then among the TLE subgroups (no BTCS, infrequent BTCS and frequent BTCS subgroup). RESULTS: Compared with controls, TLE patients had higher RMT, lower SICI and higher LICI in both hemispheres, and higher ICF in the ipsilateral hemisphere. In patients with frequent BTCS, cortical hyperexcitability in the ipsilateral hemisphere was found in a parameter-dependent manner (SICI decreased at a stimulation interval of 5 ms, and ICF increased at a stimulation interval of 15 ms) compared with patients with infrequent or no BTCS. CONCLUSIONS: Our results demonstrate that motor cortical hyper-excitability in the ipsilateral hemisphere underlies the epileptogenic network of patients with active BTCS, which is more extensive than those with infrequent or no BTCS.