Temporal lobe epilepsy surgery in children and adults: A multicenter study

Discriminating factors in access to video-EEG for epilepsy surgery in a French tertiary epilepsy center

Equitable access to care and management is a priority for patients with epilepsy and may vary depending on each country's healthcare system. As this issue has not been specifically addressed in France, we conducted a retrospective study to identify discriminating factors in access to surgery at a French tertiary epilepsy center. Initially, we examined factors previously identified in other countries as influential in surgery access, including age at diagnosis, affected side, gender, years of education, socio-professional categories, and density of general practitioners in the residential area, in 293 consecutive French-native patients with refractory medial temporal lobe epilepsy and hippocampal sclerosis (MTLE-HS). Subsequently, we conducted a case-control study comparing patients born in France with 22 patients born abroad to specifically explore migratory status. The analysis revealed that the only three factors statistically influencing the delay between the onset of epilepsy and entry into video-EEG were early age at onset (associated with a longer delay), pensioner status (associated with a longer delay), and student status (associated with a shorter delay). Migratory status, gender, and socio-economic level (indirectly reflected by the level of education and socio-professional category) were not found to be discriminatory factors in access to video-EEG. Discrepancies between our study and foreign studies may be attributed to differences in healthcare systems and medical coverage among countries. Efforts in France to improve access to surgery should focus on enhancing communication among practitioners to promptly refer any MTLE-HS patient to an epilepsy surgery center, regardless of their age.

Surgical outcomes in children with drug-resistant epilepsy and hippocampal sclerosis

BACKGROUND

Hippocampal sclerosis (HS) is a common surgical substrate in adult epilepsy surgery cohorts but variably reported in various pediatric cohorts.

OBJECTIVE

We aimed to study the epilepsy phenotype, radiological and pathological variability, seizure and neurocognitive outcomes in children with drug-resistant epilepsy and hippocampal sclerosis (HS) with or without additional subtle signal changes in anterior temporal lobe who underwent surgery.

METHODS

This retrospective study enrolled children with drug-resistant focal epilepsy and hippocampal sclerosis with or without additional subtle T2-Fluid Attenuated Inversion Recovery (FLAR)/Proton Density (PD) signal changes in anterior temporal lobe who underwent anterior temporal lobectomy with amygdalohippocampectomy. Their clinical, EEG, neuropsychological, radiological and pathological data were reviewed and summarized.

RESULTS

Thirty-six eligible patients were identified. The mean age at seizure onset was 3.7 years; 25% had daily seizures at time of surgery. Isolated HS was noted in 22 (61.1%) cases and additional subtle signal changes in ipsilateral temporal lobe in 14 (38.9%) cases. Compared to the normative population, the group mean performance in intellectual functioning and most auditory and visual memory tasks were significantly lower than the normative sample. The mean age at surgery was 12.3 years; 22 patients (61.1%) had left hemispheric surgeries. ILAE class 1 outcomes was seen in 28 (77.8%) patients after a mean follow up duration of 2.3 years. Hippocampal sclerosis was noted pathologically in 32 (88.9%) cases; type 2 (54.5%) was predominant subtype where further classification was possible. Additional pathological abnormalities were seen in 11 cases (30.6%); these had had similar rates of seizure freedom as compared to children with isolated hippocampal sclerosis/gliosis (63.6% vs 84%, p=0.21). Significant reliable changes were observed across auditory and visual memory tasks at an individual level post surgery.

CONCLUSIONS

Favourable seizure outcomes were seen in most children with isolated radiological hippocampal sclerosis. Patients with additional pathological abnormalities had similar rates of seizure freedom as compared to children with isolated hippocampal sclerosis/gliosis.

SEEG-based epileptic seizure network modeling and analysis for pre-surgery evaluation

Stereo-electroencephalography is a minimally invasive technique for patients with refractory epilepsy pursuing surgery to reduce or control seizures. Electrodes are implanted based on pre-surgery evaluations and can collect deep brain activities for surgery decisions. This paper presents a methodology to analyze stereo-electroencephalography and assist clinicians by recommending the optimal surgical option and target areas for focal epilepsy patients. A seizure network (graph) model is proposed to characterize the spatial distribution and temporal changes of ictal events. The network nodes and edges correspond to specific epileptogenic regions and propagation/impact pathways (weighted by directed transfer function), respectively. We then employ a K-means clustering strategy to group nodes into a few clusters, from which the target surgical areas can be identified. Ten patients with different types of focal seizures were thoroughly analyzed. Promising consistency between results of our method's recommendations, clinical decisions and surgery outcomes were observed.

Bilateral ictal EEG is associated with better memory outcome after hippocampal sclerosis surgery

OBJECTIVE

To compare memory outcomes after surgery for unilateral hippocampal sclerosis (HS)-associated epilepsy in patients with unilateral and bilateral ictal electrographic involvement.

METHODS

We prospectively evaluated HS patients, aged 18-55 years and IQ ≥70. Left (L) and right (R) surgical groups underwent noninvasive video-EEG monitoring and Wada test. We classified patients as Ipsilateral if ictal EEG was restricted to the HS side, or Bilateral, if at least one seizure onset occurred contralaterally to the HS, or if ictal discharge evolved to the opposite temporal region. Patients who declined surgery served as controls. Memory was evaluated on two occasions with Rey Auditory-Verbal Learning Test and Rey Visual-Design Learning Test. Baseline neuropsychological test scores were compared between groups. Pre- and postoperative scores were compared within each group. Reliable change index Z-scores (RCI) were obtained using controls as references, and compared between surgical groups.

RESULTS

We evaluated 64 patients. Patients were classified as: L-Ipsilateral (9), L-Bilateral (15), L-Control (9), R-Ipsilateral (10), R-Bilateral (9), and R-Control (12). On preoperative evaluation, memory performance did not differ among surgical groups. Right HS patients did not present postoperative memory decline. L-Ipsilateral group presented postoperative decline on immediate (P = 0.036) and delayed verbal recall (P = 0.011), while L-Bilateral did not decline. L-Ipsilateral had lower RCI Z-scores, indicating delayed verbal memory decline compared to L-Bilateral (P = 0.012).

SIGNIFICANCE

Dominant HS patients with bilateral ictal involvement presented less pronounced postoperative verbal memory decline compared to patients with exclusive ipsilateral ictal activity. Surgery was indicated in these patients regardless of memory impairment on neuropsychological testing, since resection of the left sclerotic hippocampus could result in cessation of contralateral epileptiform activity, and, therefore, improved memory function.

Application value of multimodal MRI combined with PET metabolic parameters in temporal lobe epilepsy with dual pathology

OBJECTIVES

To investigate the application value of multimodal MRI combined with PET metabolic parameters in detecting temporal lobe epilepsy (TLE) with dual pathology (DP) and the prediction effect of post-surgical outcomes in these patients.

METHODS

We retrospectively reviewed 50 patients with TLE-DP who underwent surgery at our hospital between January 2016 and December 2021 and collected the demographics, clinical characteristics, video-electroencephalography (v-EEG), neuroimaging, and surgical data. Seizure outcome data were collected during a regular follow-up of at least 12 months and were graded using Engel scores. Fisher's exact test was used to compare the differences in DP detection rates of various diagnostic modalities. Univariate and multivariate analyses were performed to explore the prognostic factors for predicting seizure outcomes post-surgery.

RESULTS

Of the 50 patients, 20 were males. The median age was 30, the median age at first seizure was 14, and the median duration was ten years. Voxel-based morphometry-PET statistical parametric mapping-PET/MRI (VBM-PSPM-PET/MRI) had the highest detection rate, followed by PET/MRI, VBM analysis, and PET-SPM. Regardless of follow-up duration, v-EEG, PET, image post-processing methods, and VBM-PSPM-PET/MRI statistically correlated with seizure outcomes using the log-rank test in the Kaplan-Meier analysis. Multivariate analysis showed that VBM-PSPM-PET/MRI was an independent predictor of TLE-DP (hazard ratio (HR) = 15.674, 95 % CI = 0.002-0.122, P < 0.00 1).

CONCLUSIONS

Our study illustrates that VBM-PSPM-PET/MRI has the highest detection value in patients with TLE-DP and can provide independent prognostic information for patients who undergo surgery. This approach has the most substantial potential for the selection of candidates for patients who undergo surgical treatment and for prognostic stratification.

Referral odyssey plot to visualize causes of surgical delay in mesial temporal lobe epilepsy with hippocampal sclerosis

The "odyssey plot" was used to visualize referral delays in epilepsy surgery. Participants were 36 patients (19 males; 13-67 years, median 27 years) with mesial temporal lobe epilepsy with hippocampal sclerosis (HS) who underwent resection surgery. The "referral odyssey plot" included five clinical episodes: seizure onset (T1), first visits to a non-epileptologist (T2) and to an epileptologist (T3), first admission to our epilepsy monitoring unit (EMU) (T4), and resection surgery (T5). For each patient, we identified the first seizure type: the physician who first diagnosed focal aware seizure (FAS), focal impaired awareness seizure (FIAS), focal to bilateral tonic-clonic seizure (FBTCS), and radiologically suspected HS. Within the overall delay (T1-T5, median 18 years; interquartile range [IQR] 14), non-epileptologist's delay (T2-T3, 11.5 years; IQR 12.25) was far (p < 0.0001) longer than patient's (T1-T2, 0 year; IQR 2.25), epileptologist's (T3-T4, 1 year; IQR 4), or after-EMU delay (T4-T5, 1 year; IQR 1). FAS onset cases had significantly longer T1-T2 (N = 5, median 7 years; IQR 6) than FIAS (N = 22, 0 year; IQR 1, p < 0.005) or FBTCS onset cases (N = 9, 0 year; IQR 0, p < 0.001). FAS was correctly diagnosed first by non-epileptologists in 17.9%, by out-patient epileptologists in 35.7%, and at the EMU in 46.4%. FIAS was correctly diagnosed first by non-epileptologists in 94.4% and by out-patient epileptologists in 5.6%. Non-epileptologists diagnosed FBTCS in all cases. HS was diagnosed by non-epileptologists in 13.9%, by out-patient epileptologists in 47.2%, and at the EMU in 38.9%. Early referral to epileptologists is most critical for early surgery. Early utilization of the EMU is highly recommended because FAS is often overlooked by outpatient epileptologists. The odyssey plot will be useful to improve the healthcare system for other types of epilepsy.

Performance of hippocampal radiomics models based on T2-FLAIR images in mesial temporal lobe epilepsy with hippocampal sclerosis

PURPOSE

Preoperative identification of hippocampal sclerosis (HS) is crucial to successful surgery for mesial temporal lobe epilepsy (MTLE). We aimed to investigate the diagnostic performance of hippocampal radiomics models based on T2 fluid-attenuated inversion recovery (FLAIR) images in MTLE with HS.

METHODS

We analysed 210 cases, including 172 HS pathology-confirmed cases (100 magnetic resonance imaging [MRI]-positive cases [MRI + HS], 72 MRI-negative HS cases [MRI - HS]), and 38 healthy controls (HC). The hippocampus was delineated slice by slice on an oblique coronal plane by a T2-FLAIR sequence, perpendicular to the hippocampus's long axis, to obtain a three-dimensional region of interest. Radiomics were processed using Artificial Intelligence Kit software; logistic regression radiomics models were constructed. The model evaluation indexes included the area under the curve (AUC), accuracy, sensitivity, and specificity.

RESULTS

The respective AUC, accuracy, sensitivity, and specificity were 0.863, 81.4%, 78.0%, and 84.6% between the MRI - HS and HC groups in the training set and 0.855, 75.0%, 68.2%, and 81.8% in the test set; 0.975, 95.0%, 92.9%, and 98.0% between the MRI + HS and HC groups in the training set and 0.954, 88.7%, 90.0%, and 87.0% in the test set; and 0.912, 84.3%, 83.3%, and 86.5% between the MTLE and HC groups in the training set and 0.854, 79.7%, 80.8%, and 77.3% in the test set. The AUC values of the comparative radiomics models were > 0.85, indicating good diagnostic efficiency.

CONCLUSION

The hippocampal radiomics models based on T2-FLAIR images can help diagnose MTLE with HS. They can be used as biological markers for MTLE diagnosis.

SEEG-based reevaluation of epileptogenic networks and the predictive role for reoperation in MTLE patients with surgical failure

OBJECTIVE

Approximately 20%-30% of mesial temporal lobe epilepsy (MTLE) patients got unfavorable seizure control after surgery, and there was a discrepancy about the reasons for the surgical failure. The functional connectivity (FC) patterns obtained from stereo-electroencephalography (SEEG) reveal information about the dynamics of the epileptic brain and the added value of extracting information that was not identifiable in the SEEG data using FC analysis. This study aims to find out the patterns of the potential epileptogenic network of failure patients and the electrophysiological predictors of reoperation.

METHODS

From January 2012 to December 2019, the MTLE patients with surgical failure were reviewed, and all patients underwent SEEG-guided reoperation. The epileptogenic network was quantified by calculating FC indicators, including phase slope index (PSI), mutual information (MI) strength, imaginary coherence (icoh), and Granger causality.

RESULTS

Ten patients with 13 seizures were included in the analysis, and 7 of them achieved a favorable outcome after the SEEG-guided reoperation. The surgical zone (SZ) with a favorable prognosis showed greater outward information flow than the non-SZ, whereas the SZ with an unfavorable prognosis showed greater inward information flow. The recurrent patients with favorable prognosis had strong connectivity between the posterior hippocampus, temporal neocortex, and insula, whereas the patients with unfavorable prognosis showed strong functional connectivity between the insula and temporal-parietal-occipital junction. The power spectrum of patients with favorable prognosis was significantly lower than that of patients with unfavorable prognosis, especially showing a more oscillation power of low frequency.

SIGNIFICANCE

The SEEG-guided reoperation could achieve favorable seizure control outcomes for recurrent patients. The FCs were a potential indicator to help construct the temporal epileptic network and predictor for the reoperative prognosis in the recurrent patients.

Seizure outcomes after resection of primary brain tumors in pediatric patients: a systematic review and meta-analysis

PURPOSE

Primary brain neoplasms are the most common solid tumors in pediatric patients and seizures are a common presenting symptom. Surgical intervention improves oncologic outcomes and seizure burden. A better understanding of factors that influence seizure outcomes in the surgical management of primary brain tumors of childhood can guide treatment approach thereby improving patient quality of life.

METHODS

We performed a systematic analysis using articles queried from PubMed, EMBASE, and Cochrane published from January 1990 to August 2022 to determine predictors of seizure outcomes in pediatric patients undergoing resection of primary brain tumors.

RESULTS

We identified 24 retrospective cohort studies, one prospective cohort study, and one mixed retrospective and prospective study for the systematic analysis. A total of 831 pediatric patients were available for analysis. 668 (80.4%) patients achieved seizure freedom after surgery. Complete tumor resection increased the likelihood of a seizure-free (Engel I) outcome compared to subtotal resection (OR 7.1, 95% CI 2.3-21.9). Rates of Engel I seizure outcomes did not significantly differ based on factors such as age at seizure onset, duration of epilepsy, gender, tumor laterality, or age at surgery, but trended towards significance for improved outcomes in temporal lobe tumors.

CONCLUSION

Primary brain tumors in the pediatric population are commonly associated with seizures. Resection of these lesions reduces seizure burden and is associated with high rates of seizure freedom. Complete resection, compared to subtotal resection, significantly increases the likelihood of seizure-free outcomes.

Identifying important factors for successful surgery in patients with lateral temporal lobe epilepsy

OBJECTIVE

Lateral temporal lobe epilepsy (LTLE) has been diagnosed in only a small number of patients; therefore, its surgical outcome is not as well-known as that of mesial temporal lobe epilepsy. We aimed to evaluate the long-term (5 years) and short-term (2 years) surgical outcomes and identify possible prognostic factors in patients with LTLE.

METHODS

This retrospective cohort study was conducted between January 1995 and December 2018 among patients who underwent resective surgery in a university-affiliated hospital. Patients were classified as LTLE if ictal onset zone was in lateral temporal area. Surgical outcomes were evaluated at 2 and 5 years. We subdivided based on outcomes and compared clinical and neuroimaging data including cortical thickness between two groups.

RESULTS

Sixty-four patients were included in the study. The mean follow-up duration after the surgery was 8.4 years. Five years after surgery, 45 of the 63 (71.4%) patients achieved seizure freedom. Clinically and statistically significant prognostic factors for postsurgical outcomes were the duration of epilepsy before surgery and focal cortical dysplasia on postoperative histopathology at the 5-year follow-up. Optimal cut-off point for epilepsy duration was eight years after the seizure onset (odds ratio 4.375, p-value = 0.0214). Furthermore, we propose a model for predicting seizure outcomes 5 years after surgery using the receiver operating characteristic curve and nomogram (area under the curve = 0.733; 95% confidence interval, 0.588-0.879). Cortical thinning was observed in ipsilateral cingulate gyrus and contralateral parietal lobe in poor surgical group compared to good surgical group (p-value < 0.01, uncorrected).

CONCLUSIONS

The identified predictors of unfavorable surgical outcomes may help in selecting optimal candidates and identifying the optimal timing for surgery among patients with LTLE. Additionally, cortical thinning was more extensive in the poor surgical group.

Intracerebral Correlates of Scalp EEG Ictal Discharges Based on Simultaneous Stereo-EEG Recordings

BACKGROUND AND OBJECTIVES

It remains unknown to what extent ictal scalp EEG can accurately predict the localization of the intracerebral seizure onset in presurgical evaluation of drug-resistant epilepsies. In this study, we aimed to define homogeneous ictal scalp EEG profiles (based on their first ictal abnormality) and assess their localizing value using simultaneously recorded scalp EEG and stereo-EEG.

METHODS

We retrospectively included consecutive patients with drug-resistant focal epilepsy who had simultaneous stereo-EEG and scalp EEG recordings of at least 1 seizure in the epileptology unit in Nancy, France. We analyzed 1 seizure per patient and used hierarchical cluster analysis to group similar seizure profiles on scalp EEG and then performed a descriptive analysis of their intracerebral correlates.

RESULTS

We enrolled 129 patients in this study. The hierarchical cluster analysis showed 6 profiles on scalp EEG first modification. None were specific to a single intracerebral localization. The "normal EEG" and "blurred EEG" clusters (early muscle artifacts) comprised only 5 patients each and corresponded to no preferential intracerebral localization. The "temporal discharge" cluster (n = 46) was characterized by theta or delta discharges on ipsilateral anterior temporal scalp electrodes and corresponded to a preferential mesial temporal intracerebral localization. The "posterior discharge" cluster (n = 42) was characterized by posterior ipsilateral or contralateral rhythmic alpha discharges or slow waves on scalp and corresponded to a preferential temporal localization. However, this profile was the statistically most frequent scalp EEG correlate of occipital and parietal seizures. The "diffuse suppression" cluster (n = 9) was characterized by a bilateral and diffuse background activity suppression on scalp and corresponded to mesial, and particularly insulo-opercular, localization. Finally, the "frontal discharge" cluster (n = 22) was characterized by bilateral frontal rhythmic fast activity or preictal spike on scalp and corresponded to preferential ventrodorsal frontal intracerebral localizations.

DISCUSSION

The hierarchical cluster analysis identified 6 seizure profiles regarding the first abnormality on scalp EEG. None of them were specific of a single intracerebral localization. Nevertheless, the strong relationships between the "temporal," "frontal," "diffuse suppression," and "posterior" profiles and intracerebral discharge localizations may contribute to hierarchize hypotheses derived from ictal scalp EEG analysis regarding intracerebral seizure onset.

Therapeutic Strategies to Ameliorate Neuronal Damage in Epilepsy by Regulating Oxidative Stress, Mitochondrial Dysfunction, and Neuroinflammation

Epilepsy is a central nervous system disorder involving spontaneous and recurring seizures that affects 50 million individuals globally. Because approximately one-third of patients with epilepsy do not respond to drug therapy, the development of new therapeutic strategies against epilepsy could be beneficial. Oxidative stress and mitochondrial dysfunction are frequently observed in epilepsy. Additionally, neuroinflammation is increasingly understood to contribute to the pathogenesis of epilepsy. Mitochondrial dysfunction is also recognized for its contributions to neuronal excitability and apoptosis, which can lead to neuronal loss in epilepsy. This review focuses on the roles of oxidative damage, mitochondrial dysfunction, NAPDH oxidase, the blood-brain barrier, excitotoxicity, and neuroinflammation in the development of epilepsy. We also review the therapies used to treat epilepsy and prevent seizures, including anti-seizure medications, anti-epileptic drugs, anti-inflammatory therapies, and antioxidant therapies. In addition, we review the use of neuromodulation and surgery in the treatment of epilepsy. Finally, we present the role of dietary and nutritional strategies in the management of epilepsy, including the ketogenic diet and the intake of vitamins, polyphenols, and flavonoids. By reviewing available interventions and research on the pathophysiology of epilepsy, this review points to areas of further development for therapies that can manage epilepsy.

New insights for predicting surgery outcome in patients with temporal lobe epilepsy. A systematic review

Resective surgery is the treatment of choice for one-third of adult patients with focal, drug-resistant epilepsy. This procedure is associated with substantial clinical and cognitive risks. In clinical practice, there is no validated model for epilepsy surgery outcome prediction (ESOP). Meta-analyses on ESOP studies assessing prognostic factors report discrepancies in terms of study design. Our review aims to systematically investigate methodological and analytical aspects of studies predicting clinical and cognitive outcomes after temporal lobe epilepsy surgery. A systematic review of ESOP studies published between 2000 and 2022 from three databases (MEDLINE, Web of Science, and PsycINFO) was completed by following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. It yielded 4867 articles. Among them, 21 corresponded to our inclusion criteria and were therefore retained in the final review. The risk of bias was assessed using A Tool to Assess Risk of Bias and Applicability of Prediction Model Studies (PROBAST). Data extracted from the 21 studies were analyzed using narrative synthesis and descriptive statistics. Our findings show an increase in the use of multimodal datasets and machine learning analyses in recent ESOP studies, although regression remained the most frequently used approach. We also identified a more frequent use of network notions in recent ESOP studies. Nevertheless, several methodological issues were noted, such as small sample sizes, lack of information on the follow-up period, variability in seizure outcome, and the definition of neuropsychological postoperative change. Of 21 studies, only one provided a clinical tool to anticipate the cognitive outcome after epilepsy surgery. We conclude that methodological issues should be overcome before we move towards more complete models to better predict clinical and cognitive outcomes after epilepsy surgery. Recommendations for future studies to harness the possibilities of multimodal datasets and data fusion, are provided. A stronger bridge between fundamental and clinical research may result in developing accessible clinical tools.

Stereoelectroencephalography followed by combined electrode removal and MRI-guided laser interstitial thermal therapy or open resection: a single-center series in pediatric patients with medically refractory epilepsy

OBJECTIVE

Stereoelectroencephalography (SEEG) and MRI-guided laser interstitial thermal therapy (MRgLITT) have emerged as safe, effective, and less invasive alternatives to subdural grid placement and open resection, respectively, for the localization and treatment of medically refractory epilepsy (MRE) in children. Reported pediatric experience combining these complementary techniques is limited, with traditional workflows separating electrode removal and ablation/resection. The authors describe the largest reported series of pediatric epilepsy patients who underwent MRgLITT following SEEG contrasted with a cohort that underwent craniotomy following SEEG, combining ablation/resection with electrode explantation as standard practice.

METHODS

The medical records of all patients with MRE who had undergone SEEG followed by MRgLITT or open resection/disconnection at Boston Children's Hospital between November 2015 and December 2020 were retrospectively reviewed. Primary outcome variables included surgical complication rates, length of hospital stay following treatment, and Engel classification at the last follow-up.

RESULTS

Of 74 SEEG patients, 27 (median age 12.1 years, 63% female) underwent MRgLITT and 47 (median age 12.1 years, 49% female) underwent craniotomy. Seventy patients (95%) underwent SEEG followed by combined electrode removal and treatment. Eight MRgLITT cases (30%) and no open cases targeted the insula (p < 0.001). Complication rates did not differ, although trends toward more subdural/epidural hematomas, infarcts, and permanent unanticipated neurological deficits were evident following craniotomy, whereas a trend toward more temporary unanticipated neurological deficits was seen following MRgLITT. The median duration of hospitalization after treatment was 3 and 5 days for MRgLITT and open cases, respectively (p = 0.078). Seizure outcomes were similar between the cohorts, with 74% of MRgLITT and craniotomy patients attaining Engel class I or II outcomes (p = 0.386) at the last follow-up (median 1.1 and 1.9 years, respectively).

CONCLUSIONS

MRgLITT and open resection following SEEG can both effectively treat MRE in pediatric patients and generally can be performed in a two-surgery workflow during a single hospitalization. In appropriately selected patients, MRgLITT tended to be associated with shorter hospitalizations and fewer complications following treatment and may be best suited for focal deep-seated targets associated with relatively challenging open surgical approaches.

Predictors of outcomes after surgery for medically intractable insular epilepsy: A systematic review and individual participant data meta-analysis

Insular epilepsy (IE) is an increasingly recognized cause of drug-resistant epilepsy amenable to surgery. However, concerns of suboptimal seizure control and permanent neurological morbidity hamper widespread adoption of surgery for IE. We performed a systematic review and individual participant data meta-analysis to determine the efficacy and safety profile of surgery for IE and identify predictors of outcomes. Of 2483 unique citations, 24 retrospective studies reporting on 312 participants were eligible for inclusion. The median follow-up duration was 2.58 years (range, 0-17 years), and 206 (66.7%) patients were seizure-free at last follow-up. Younger age at surgery (≤18 years; HR = 1.70, 95% CI = 1.09-2.66, P = .022) and invasive EEG monitoring (HR = 1.97, 95% CI = 1.04-3.74, P = .039) were significantly associated with shorter time to seizure recurrence. Performing MR-guided laser ablation or radiofrequency ablation instead of open resection (OR = 2.05, 95% CI = 1.08-3.89, P = .028) was independently associated with suboptimal or poor seizure outcome (Engel II-IV) at last follow-up. Postoperative neurological complications occurred in 42.5% of patients, most commonly motor deficits (29.9%). Permanent neurological complications occurred in 7.8% of surgeries, including 5% and 1.4% rate of permanent motor deficits and dysphasia, respectively. Resection of the frontal operculum was independently associated with greater odds of motor deficits (OR = 2.75, 95% CI = 1.46-5.15, P = .002). Dominant-hemisphere resections were independently associated with dysphasia (OR = 13.09, 95% CI = 2.22-77.14, P = .005) albeit none of the observed language deficits were permanent. Surgery for IE is associated with a good efficacy/safety profile. Most patients experience seizure freedom, and neurological deficits are predominantly transient. Pediatric patients and those requiring invasive monitoring or undergoing stereotactic ablation procedures experience lower rates of seizure freedom. Transgression of the frontal operculum should be avoided if it is not deemed part of the epileptogenic zone. Well-selected candidates undergoing dominant-hemisphere resection are more likely to exhibit transient language deficits; however, the risk of permanent deficit is very low.

The differential role of magnetic resonance imaging in predicting surgical outcomes between children versus adults with temporal lobe epilepsy

OBJECTIVE

This study aims to investigate the clinical discrepancies and the different predictors of anterior temporal lobectomy (ATL) in children (<18 years at surgery) and adults (>18 years at surgery) with temporal lobe epilepsy (TLE).

MATERIALS AND METHODS

A total of 262 patients (56 children and 206 adults) with TLE who underwent ATL were included in this study. The clinical variables, including patients' characteristics, preoperative evaluations, pathology, surgical prognosis, and surgical predictors were assessed the discrepancies between TLE children versus adults using univariate and multivariate analyses. Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom and AEDs withdrawal after ATL, and the difference between TLE children and adults was analyzed using the Log-Rank test.

RESULTS

There were significant differences including semiology, magnetic resonance imaging (MRI) examinations, numbers of preoperative AEDs, and pathologies between TLE children and adults (P < 0.05, Q < 0.05). The MRI-detected epileptic focus was the only independent predictor of seizure freedom (P = 0.002, Q = 0.036) in TLE children, and the concordance of MRI-detected focus with video-electroencephalography (video-EEG)-detected epileptic zone was the only variable associated with seizure freedom in TLE adults (OR = 2.686, 95% CI = 1.014-7.115, P = 0.047). The TLE children experienced a higher probability of AEDs withdrawal than adults after surgery (P = 0.005).

SIGNIFICANCE

There were remarkable differences in clinical manifestations, MRI examinations, number of preoperative AEDs, and pathologies between TLE children versus adults. TLE children had a higher possibility of AEDs withdrawal than adults after surgery. The favorable seizure outcome of ATL depended on the early complete resection of MRI-detected epileptogenic focus in TLE children, while the concordance of MRI-detected focus with EEG-detected epileptogenic zone was the only predictor of favorable seizure outcomes in TLE adults.

Seizure Outcome of Temporal Lobe Epilepsy Surgery in Adults and Children: A Systematic Review and Meta-Analysis

BACKGROUND

Temporal lobe epilepsy (TLE) surgery is associated with the best seizure outcome in adults, although its long-term results remain suboptimal. Retrospective pediatric studies suggest better figures whose determinants are poorly understood.

OBJECTIVE

To conduct a systematic review and meta-analysis of studies on the efficacy of TLE surgery in children (age younger than 18 years) and adults.

METHODS

We searched MEDLINE, Embase, and Cochrane Library for TLE surgery original research from January 1, 1990, until May 12, 2020. The outcome measures were seizure freedom since surgery and seizure freedom either at last or longest follow-up. We meta-analyzed the proportion of children and adults achieving either Engel I/International League Against Epilepsy (ILAE) 1 or Engel IA/ILAE 1A outcome by follow-up duration, type of surgery, histopathology, neuroimaging, quality of the studies, and publication period. We used a random effects model with Freeman-Tukey double arcsine transformation of proportions.

RESULTS

From 40 409 records identified, we included 277 studies (30 848 patients). The proportions of patients achieving Engel I/ILAE 1 and Engel IA/ILAE 1A outcomes were 0.74 (95% CI, 0.69-0.78) and 0.61 (0.48-0.74) for children and 0.69 (0.67-0.71) and 0.56 (0.52-0.60) for adults. Histopathology significantly influenced Engel I/ILAE 1 outcome in adults but not in children (P < .0001), while the type of surgery significantly influenced Engel I/ILAE 1 outcome in children but not in adults.

CONCLUSION

The proportion of seizure freedom after TLE surgery was higher in children, although not significantly. Histopathology and the surgical approach can influence seizure outcome, with age-related variability.

Brain Surgery for Medically Intractable Epilepsy

This review covers the broad topic of brain surgery in the treatment of pediatric intractable epilepsy. The authors review the latest advancements in the presurgical workup as well as the mandatory tests needed to explore the epilepsy workup in these children. They describe the different types of epilepsy from a surgical standpoint (temporal, extratemporal, multifocal, and hemispheric epilepsies) and various surgical procedures that can be proposed depending on the clinical scenario: lesionectomies, lobectomies, hemispherectomies, neuromodulation, and palliative surgeries. They also describe the key differences of the pediatric patient as compared with the adult patient in such pathologic conditions.

Knowledge and attitudes of neurologists toward epilepsy surgery: an Italian survey

The current study, conceived with the contribution of the Commission for Epilepsy Surgery of the Italian League Against Epilepsy (LICE) and the Epilepsy Study Group of the Italian Neurological Society (SIN), aimed to assess potential physician-related barriers to refer subjects for epilepsy surgery. All the members of SIN and LICE were invited by email to complete a 28-item online questionnaire. The survey items included: (1) individual and medical practice characteristics, (2) knowledge of current indications to select candidates for epilepsy surgery, (3) factors potentially affecting the attitude toward epilepsy surgery. Overall, 210 physicians completed the survey. More than half (63.3%) of the participants showed proper knowledge of the ILAE drug-resistance. Definition and almost two-thirds of them (71.9%) considered themselves adequately informed about indications, risks, and benefits of epilepsy surgery. Surgery was regarded as a valid option to be used as early as possible by 84.8% of the interviewees, and 71% of them estimated its complication rate to be low. However, more than half (63%) of the respondents reportedly referred patients for surgery only after the failure of 3–5 antiseizure medications. Overestimation of risks/complications of surgery and inadequate healthcare resources were identified as the main factor contrasting the patient referral for surgery by 43% and 40.5% of the participants, respectively. In conclusion, this survey confirms the existence of knowledge gap within both physicians and the healthcare system, as well as an educational need regarding epilepsy surgery. Further researches are warranted to define learning outcomes and optimize educational tools.

Auditory verbal learning test can lateralize hippocampal sclerosis

The ability of the Auditory Verbal Learning Test (AVLT) to lateralize hippocampal sclerosis (HS) in mesial temporal lobe epilepsy (MTLE) was explored in a sample of 50 patients with MTLE-HS (23 right and 27 left). Patients' AVLT scores were adjusted to the demographic characteristics of each individual in accordance with the Portuguese normative data. The laterality of the HS was determined by consensus by two neuroradiologists. ROC curves were used to identify the best AVLT cutoff scores to differentiate right vs. left HS. Diagnostic statistics were applied to different AVLT measures. The study results revealed that four AVLT scores can correctly classify the laterality of HS in the total sample and a sub-group of 39 right-handed patients (Edinburgh Laterality Inventory +100): delayed recall trial (76 and 80%, respectively), delayed recognition trial (64 and 67%, respectively), learning over trials index (64 and 74%, respectively), and long-term percent retention index (68 and 72%, respectively). In right-handed patients, the diagnostic capability of the delayed recall trial was improved by pairing it with the learning over trials index (accuracy of 85%). In sum, AVLT measures of verbal memory differentiate left from right HS in MTLE. The delayed recall trial demonstrated good diagnostic capacity.

The Temporal Lobe as a Symptomatogenic Zone in Medial Parietal Lobe Epilepsy

Some surgical failures after temporal lobe epilepsy surgery may be due to the presence of an extratemporal epileptogenic zone. Of particular interest is the medial parietal lobe due to its robust connectivity with mesial temporal structures. Seizures in that area may be clinically silent before propagating to the symptomatogenic temporal lobe. In this paper, we present an overview of the anatomical connectivity, semiology, radiology, electroencephalography, neuropsychology, and outcomes in medial parietal lobe epilepsy. We also present two illustrative cases of seizures originating from the precuneus and the posterior cingulate cortex. We conclude that the medial parietal lobe should be strongly considered for sampling by intracranial electrodes in individuals with nonlesional temporal lobe epilepsy, especially if scrutinizing the presurgical data produces discordant findings.

Surgical outcome of temporal plus epilepsy is improved by multilobar resection

OBJECTIVE

Temporal plus epilepsy (TPE) represents a rare type of epilepsy characterized by a complex epileptogenic zone including the temporal lobe and the close neighboring structures. We investigated whether the complete resection of temporal plus epileptogenic zone as defined through stereoelectroencephalography (SEEG) might improve seizure outcome in 38 patients with TPE.

METHODS

Inclusion criteria were as follows: epilepsy surgery performed between January 1990 and December 2001, SEEG defining a temporal plus epileptogenic zone, unilobar temporal operations ("temporal lobe epilepsy [TLE] surgery") or multilobar interventions including the temporal lobe ("TPE surgery"), magnetic resonance imaging either normal or showing signs of hippocampal sclerosis, and postoperative follow-up of at least 12 months. For each assessment of postoperative seizure outcome, at 1, 2, 5, and 10 years, we carried out descriptive analysis and classical tests of hypothesis, namely, Pearson χ² test or Fisher exact test of independence on tables of frequency for each categorical variable of interest and Student t-test for each continuous variable of interest, when appropriate.

RESULTS

Twenty-one patients underwent TPE surgery and 17 underwent TLE surgery with a follow-up of 12.4 ± 8.16 years. In the multivariate models, there was a significant effect of the time from surgery on Engel Class IA versus IB-IV outcome, with a steadily worsening trend from 5-year follow-up onward. TPE surgery was associated with better results than TLE surgery.

SIGNIFICANCE

This study suggests that surgical outcome in patients with TPE can be improved by a tailored, multilobar resection and confirms that SEEG is mandatory when a TPE is suspected.

Histopathological Correlations of Qualitative and Quantitative Temporopolar MRI Analyses in Patients With Hippocampal Sclerosis

Hippocampal sclerosis (HS) is a common cause of pharmacoresistant focal epilepsy. Here, we (1) performed a histological approach to the anterior temporal pole of patients with HS to evaluate cortical and white matter (WM) cell populations, alteration of myelin integrity and markers of neuronal activity, and (2) correlated microscopic data with magnetic resonance imaging (MRI) findings. Our aim was to contribute with the understanding of neuroimaging and pathophysiological mechanisms of temporal lobe epilepsy (TLE) associated with HS. We examined MRIs and surgical specimens from the anterior temporal pole from TLE-HS patients (n = 9) and compared them with 10 autopsy controls. MRIs from healthy volunteers (n = 13) were used as neuroimaging controls. Histological techniques were performed to assess oligodendrocytes, heterotopic neurons, cellular proliferative index, and myeloarchitecture integrity of the WM, as well as markers of acute (c-fos) and chronic (ΔFosB) activities of neocortical neurons. Microscopic data were compared with neuroimaging findings, including T2-weighted/FLAIR MRI temporopolar blurring and values of fractional anisotropy (FA) from diffusion-weighed imaging (DWI). We found a significant increase in WM oligodendrocyte number, both in hematoxylin and eosin, and in Olig2-stained sections. The frequencies of oligodendrocytes in perivascular spaces and around heterotopic neurons were significantly higher in patients with TLE–HS compared with controls. The percentage of 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase; a marker of myeloarchitecture integrity) immunopositive area in the WM was significantly higher in TLE-HS, as well as the numbers of c-fos- and ΔFosB-immunostained neocortical neurons. Additionally, we demonstrated a decrease in axonal bundle integrity on neuroimaging, with a significant reduction in the FA in the anterior temporal pole. No differences were detected between individuals with and without temporopolar blurring on visual MRI analysis, considering the number of oligodendroglial cells and percentage of WM CNPase-positive areas. Also, there was no relationship between T2 relaxometry and oligodendrocyte count. In conclusion, our histopathological data support the following: (1) the hypothesis that repetitive neocortical neuronal activity could induce changes in the WM cellular constitution and myelin remodeling in the anterior temporal pole from patients with TLE-HS, (2) that oligodendroglial hyperplasia is not related to temporal blurring or T2 signal intensity on MRI, and (3) that reduced FA is a marker of increase in Olig2-immunopositive cells in superficial temporopolar WM from patients with TLE-HS.

Early epilepsy surgery for non drug-resistant patients

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Absence of drug-resistance is predictor of better post-surgical outcome.

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Post-surgical outcome in non drug-resistant patients is favourable irrespective of both the localization of surgery and the histological diagnosis.

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Non drug-resistant patients who underwent epilepsy surgery are more likely to successfully discontinue ASMs.

The aim of epilepsy treatment is to achieve seizure freedom. Surgery is often still considered a late option when pharmacological treatments have failed and epilepsy has become drug-resistant.

We analyse the clinical features and surgical outcome in patients who underwent surgery without experiencing drug-resistance comparing with those observed in patients who became drug-resistant.

Two-hundred and fifty patients with symptomatic focal epilepsy (12.1% of patients who underwent surgery at the “Claudio Munari” Epilepsy Surgery Center) were selected on the basis of initial period of seizure freedom and followed-up for at least 12 months. Patients were divided into two groups: those who underwent surgery during the initial period of seizure freedom (n = 74), and those who underwent surgery after an initial seizure-free period followed by drug-resistance (n = 176).

Outcomes were significantly better in non-drug-resistant patients (p < 0.001), all of whom had Engel class Ia or Ic. In the drug-resistant group, 136 patients (77.3%) had class Ia or Ic. The median post-operative follow-up was respectively 75.0 and 84.0 months.

Epilepsy surgery is a successful treatment, especially for non-drug-resistant patients with focal epilepsy with structural etiology. The timing of surgery affects the outcomes, and “early” surgery should be preferred to prevent likely drug-resistance and to improve prognosis.

The 50th anniversary of the Italian League Against Epilepsy (Lega Italiana Contro l’Epilessia)

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We describe the 50-year history of the Italian League Against Epilepsy (LICE).

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LICE promotes high-quality epilepsy care, education and research into epilepsy.

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LICE maintains close relations with ILAE and other professional societies.

This article was prepared to outline the article collection submitted on behalf of Lega Italiana Contro l’Epilepsia, or LICE, for the 50th anniversary of the founding of the ILAE Italian Chapter, and provides a brief summary of the history, with its landmark achievements and challenges. LICE is a multidisciplinary, inclusive, educational, informative and multifaceted organization. Initially in 1955 and then formally in 1972, LICE was born in Milano, with the mission to devote itself to people suffering with epilepsy and by promoting appropriate treatment and care, integration into society, to promote and pursue all kinds of activities designed to achieve those aims. The LICE is currently composed of more than 1000 members including neurologists, pediatric neurologists, neurosurgeons, neurophysiologists, and neuropsychologists who function throughout Italy dealing mainly or exclusively with the diagnosis and treatment of people with epilepsy.

Semiology, EEG, and neuroimaging findings in temporal lobe epilepsies

Temporal lobe epilepsy (TLE) is the most common type of focal epilepsy. First descriptions of TLE date back in time and detailed portraits of epileptic seizures of temporal origin can be found in early medical reports as well as in the works of various artists and dramatists. Depending on the seizure onset zone, several subtypes of TLE have been identified, each one associated with peculiar ictal semiology. TLE can result from multiple etiological causes, ranging from genetic to lesional ones. While the diagnosis of TLE relies on detailed analysis of clinical as well as electroencephalographic (EEG) features, the lesions responsible for seizure generation can be highlighted by multiple brain imaging modalities or, in selected cases, by genetic investigations. TLE is the most common cause of refractory epilepsy and despite the great advances in diagnostic tools, no lesion is found in around one-third of patients. Surgical treatment is a safe and effective option, requiring presurgical investigations to accurately identify the seizure onset zone (SOZ). In selected cases, presurgical investigations need intracerebral investigations (such as stereoelectroencephalography) or dedicated metabolic imaging techniques (interictal PET and ictal SPECT) to correctly identify the brain structures to be removed.

Surgery procedures in temporal lobe epilepsies

Temporal lobe epilepsy (TLE) is the most common cause of refractory epilepsy amenable for surgical treatment and seizure control. Surgery for TLE is a safe and effective strategy. The seizure-free rate after surgical resection in patients with mesial or neocortical TLE is about 70%. Resective surgery has an advantage over stereotactic radiosurgery in terms of seizure outcomes for mesial TLE patients. Both techniques have similar results for safety, cognitive outcomes, and associated costs. Stereotactic radiosurgery should therefore be seen as an alternative to open surgery for patients with contraindications for or with reluctance to undergo open surgery. Laser interstitial thermal therapy (LITT) has also shown promising results as a curative technique in mesial TLE but needs to be more deeply evaluated. Brain-responsive stimulation represents a palliative treatment option for patients with unilateral or bilateral MTLE who are not candidates for temporal lobectomy or who have failed a prior mesial temporal lobe resection. Overall, despite the expansion of innovative techniques in recent years, resective surgery remains the reference treatment for TLE and should be proposed as the first-line surgical modality. In the future, ultrasound therapies could become a credible therapeutic option for refractory TLE patients.

Is the anatomical lesion always guilty?: A case report

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The presence of a lesion on MRI should not be considered as sufficient to identify epileptogenic zone.

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The epileptogenic zone can be independent of the anatomical lesion.

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The presurgical evaluation is a gradual and tailored process on patient’s epilepsy.

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The invasive investigations could clarify the doubts in the epilepsy surgery work-up.

During a presurgical workup, when discordant structural and electroclinical localization is identified, further evaluation with invasive EEG is often necessary. We report a 44-year-old right-handed woman without significant risk factors for epilepsy who presented at 11 years of age with focal seizures manifest as jerking of the left side of her mouth and arm with frequent evolution to bilateral tonic-clonic seizures during sleep with a weekly frequency. During video-EEG monitoring, we observed interictal left fronto-central sharp waves and some independent sharp waves in the right fronto-central region. Habitual seizures were recorded and during the post-ictal state, the patient had left arm weakness for a few minutes. The ictal discharge on EEG was characterized by a bilateral fronto-central rhythmic slow activity more prevalent over the right hemisphere. MRI of the brain revealed a left precentral structural lesion. Considering the discordant structural and electroclinical information, we performed bilateral fronto-central stereo-EEG implantation and demonstrated clear right fronto-central seizure onset. Stereo-EEG-guided radiofrequency thermocoagulation was performed in the right fronto-central leads with subsequent seizure freedom for 9 months. The patient then underwent surgery (right fronto-central cortectomy), and histology revealed focal cortical dysplasia type Ia. The post-surgical outcome was Engel Ia. This case underscores the presence of a structural lesion is not sufficient to define the epileptogenic zone if not supported by clinical and EEG evidence. In such cases, an invasive investigation is typically required.

Surgery for Intractable Epilepsy in Pediatrics, a Systematic Review of Outcomes other than Seizure Freedom

To perform a systematic review evaluating reported outcomes for epilepsy surgery in pediatric patients with pharmacoresistant epilepsy beyond seizure control, including impact on quality of life, behavioral, neurocognitive outcomes as well as complications, and death. We reviewed articles from both EMBASE and MEDLINE/PubMed articles that met formal criteria (patients ≤18 years, those with intractable epilepsy, at least 5 patients in the case series, published in peer-reviewed journal). Each reviewer independently reviewed the articles and those with discrepancies were discussed and consensus was reached. Out of a total of 536 abstracts obtained from EMBASE and MEDLINE/PubMed searches combined with additional cross-referencing, a total of 98 manuscripts ultimately met all inclusion criteria. The manuscripts were divided into 3 outcomes categories: Quality of Life (16), Cognitive Outcomes (60), and Deficits and Complications (50). Several papers fell into more than 1 category. These were separated by surgical types and evaluated. We found that overall reporting in all domains was variable and inconsistent amongst the different studies. This systematic review highlights the lack of completeness in reporting outcomes and complications involving pediatric epilepsy surgery and discordant results. This underscores the importance of multicenter systematic prospective data collection in pediatric patients who undergo pediatric epilepsy surgery.

A zebrafish-centric approach to antiepileptic drug development

Danio rerio (zebrafish) are a powerful experimental model for genetic and developmental studies. Adaptation of zebrafish to study seizures was initially established using the common convulsant agent pentylenetetrazole (PTZ). Larval PTZ-exposed zebrafish exhibit clear behavioral convulsions and abnormal electrographic activity, reminiscent of interictal and ictal epileptiform discharge. By using this model, our laboratory developed simple locomotion-based and electrophysiological assays to monitor and quantify seizures in larval zebrafish. Zebrafish also offer multiple advantages for rapid genetic manipulation and high-throughput phenotype-based drug screening. Combining these seizure assays with genetically modified zebrafish that represent Dravet syndrome, a rare genetic epilepsy, ultimately contributed to a phenotype-based screen of over 3500 drugs. Several drugs identified in these zebrafish screens are currently in clinical or compassionate-use trials. The emergence of this 'aquarium-to-bedside' approach suggests that broader efforts to adapt and improve upon this zebrafish-centric strategy can drive a variety of exciting new discoveries.

Distinct changes of brain cortical thickness relate to post-treatment outcomes in children with epilepsy

PURPOSE

In the current study, we examined the potential of neuroanatomic measures to cluster patients into different subgroups and established their clinical relevance to post-treatment outcomes.

METHODS

We included seventy-two children with epilepsy (aged 14-195 months) who were treated with anti-seizure medication alone and 39 healthy participants (aged 36-60 months). High-resolution T1-weighted imaging was performed for all participants, and brain cortical thickness measurements were obtained for 68 cortical regions for each of them. Amongst the patients, data-driven hierarchical cluster analysis was performed using the selected cortical thickness measures as features. The average thickness measures in each of the 68 brain regions were then compared between patient subgroups and healthy controls.

RESULTS

Two distinct patient subgroups were identified but were not related to the clinical types. Patients within subgroup 1 (n = 56) had a significantly higher rate of recurrent seizure than those in subgroup 2 (n = 16) (41.1% vs. 14.3%, p<0.05), while the follow-up time or medication did not differ between them. This finding was further confirmed by a recent follow-up through phone calls. The demographic variables, rate of electroencephalogram abnormalities, or sleep problems did not significantly differ between patient subgroups. Compared with healthy controls, patients in subgroup 1 showed significantly increased cortical thickness in the neocortex, whereas patients in subgroup 2 only showed regional cortical thinning in the right superior temporal gyrus.

CONCLUSION

These findings suggest the potential existence of distinct subgroups of children with epilepsy that were especially relevant to the differential patterns of post-treatment outcomes, with regional cortical thinning in the temporal regions relative to controls predicting lower risk of recurrent seizure.

The surgical treatment of epilepsy

In 2009, the Commission for Epilepsy Surgery of the Italian League Against Epilepsy (LICE) conducted an overview about the techniques used for the pre-surgical evaluation and the surgical treatment of epilepsies. The recognition that, in selected cases, surgery can be considered the first-line approach, suggested that the experience gained by the main Italian referral centers should be pooled in order to provide a handy source of reference. In light of the progress made over these past years, some parts of that first report have accordingly been updated. The present revision aims to harmonize the general principles regulating the patient selection and the pre-surgical work-up, as well as to expand the use of epilepsy surgery, that still represents an underutilized resource, regrettably. The objective of this contribution is drawing up a methodological framework within which to integrate the experiences of each group in this complex and dynamic sector of the neurosciences.