Mosaic trisomy of chromosome 1q in human brain tissue associates with unilateral polymicrogyria, very early-onset focal epilepsy, and severe developmental delay

Polymicrogyria (PMG) is a developmental cortical malformation characterized by an excess of small and frustrane gyration and abnormal cortical lamination. PMG frequently associates with seizures. The molecular pathomechanisms underlying PMG development are not yet understood. About 40 genes have been associated with PMG, and small copy number variations have also been described in selected patients. We recently provided evidence that epilepsy-associated structural brain lesions can be classified based on genomic DNA methylation patterns. Here, we analyzed 26 PMG patients employing array-based DNA methylation profiling on formalin-fixed paraffin-embedded material. A series of 62 well-characterized non-PMG cortical malformations (focal cortical dysplasia type 2a/b and hemimegalencephaly), temporal lobe epilepsy, and non-epilepsy autopsy controls was used as reference cohort. Unsupervised dimensionality reduction and hierarchical cluster analysis of DNA methylation profiles showed that PMG formed a distinct DNA methylation class. Copy number profiling from DNA methylation data identified a uniform duplication spanning the entire long arm of chromosome 1 in 7 out of 26 PMG patients, which was verified by additional fluorescence in situ hybridization analysis. In respective cases, about 50% of nuclei in the center of the PMG lesion were 1q triploid. No chromosomal imbalance was seen in adjacent, architecturally normal-appearing tissue indicating mosaicism. Clinically, PMG 1q patients presented with a unilateral frontal or hemispheric PMG without hemimegalencephaly, a severe form of intractable epilepsy with seizure onset in the first months of life, and severe developmental delay. Our results show that PMG can be classified among other structural brain lesions according to their DNA methylation profile. One subset of PMG with distinct clinical features exhibits a duplication of chromosomal arm 1q.

Connectome biomarkers of drug-resistant epilepsy

Drug-resistant epilepsy (DRE) considerably affects patient health, cognition, and well-being, and disproportionally contributes to the overall burden of epilepsy. The most common DRE syndromes are temporal lobe epilepsy related to mesiotemporal sclerosis and extratemporal epilepsy related to cortical malformations. Both syndromes have been traditionally considered as "focal," and most patients benefit from brain surgery for long-term seizure control. However, increasing evidence indicates that many DRE patients also present with widespread structural and functional network disruptions. These anomalies have been suggested to relate to cognitive impairment and prognosis, highlighting their importance for patient management. The advent of multimodal neuroimaging and formal methods to quantify complex systems has offered unprecedented ability to profile structural and functional brain networks in DRE patients. Here, we performed a systematic review on existing DRE network biomarker candidates and their contribution to three key application areas: (1) modeling of cognitive impairments, (2) localization of the surgical target, and (3) prediction of clinical and cognitive outcomes after surgery. Although network biomarkers hold promise for a range of clinical applications, translation of neuroimaging biomarkers to the patient's bedside has been challenged by a lack of clinical and prospective studies. We therefore close by highlighting conceptual and methodological strategies to improve the evaluation and accessibility of network biomarkers, and ultimately guide clinically actionable decisions.

Quantitative analysis of intraoperative electrocorticography mirrors histopathology and seizure outcome after epileptic surgery in children

BACKGROUND

Epileptic surgery is the potentially curative treatment for children with refractory seizures. The study aimed to quantify and analyze high frequency oscillation (HFO) ripples and interictal epileptiform discharges (EDs) in intraoperative electrocorticography (ECoG) between malformation of cortical dysplasia (MCD) and non-MCD children with MRI-lesional focal epilepsy, and evaluate of seizure outcomes after epileptic surgery.

METHODS

The intraoperative ECoG was performed before and after lesionectomy. Quantifications of HFO ripples and interictal EDs of ECoG by frequency, amplitude, and foci of intraoperative ECoG were performed based on electrode location, and the characteristics of ECoG recordings were analyzed in each patient based on their histopathology. Seizure outcome after surgery according to their quantitative ECoG findings was analyzed.

RESULTS

Frequency of EDs and HFO ripple rates in preresection ECoG were significantly higher in children with MCD compared with non-MCD (p = 0.018 and p = 0.002, respectively). Higher frequencies of EDs and ripple rates in preresection ECoG were observed in residual seizures than in seizure-free children (p = 0.045 and p = 0.005, respectively). Clinically, children with residual seizures after surgery were significantly younger at the onset, had a trend of higher seizure frequency and higher spike frequency of presurgical videoEEG.

CONCLUSION

Our results suggested that quantification of intraoperative ECoG predicted seizure outcomes and reflected different ED pattern and frequencies between MCD and non-dysplastic histopathology among children who underwent resective epileptic surgery. The results of our study were encouraging and indicated that intraoperative ECoG improved the outcomes of surgery in children with epilepsy.

Change in Patient Flow in the Epilepsy Care Network Due to Novel Coronavirus Infection: An Opportunity to Strengthen Local Interdisciplinary Epilepsy Care With General Physicians

Introduction: Novel coronavirus disease 2019 (COVID-19) infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is spreading worldwide. We hypothesized that patient flow in epilepsy care would change as a result of the COVID-19 pandemic. The purpose of this study was to compare the number of patients who visited our epilepsy center before and during the first peak of the pandemic. Methods: We recorded the number of patients with epilepsy referred from general physicians (GPs) to our hospital (GP-H group), the number of patients who visited our hospital on a regular basis (R group), and the number of patients referred from our hospital to GPs (H-GP group) between July 2019 and June 2020. Results: A total of 1,839 epilepsy patients made 4,197 visits to our hospital: 979 males and 860 females (age range, 0-94 years; mean age, 37.6 years; median age, 34 years). There were 433 patients in the GP-H group (247 before the pandemic, 186 during the first peak of the pandemic; p = 0.008). In the R group, 1,406 patients made 3,764 visits (1,992 visits before the pandemic, 1,772 during the first peak of the pandemic). In the H-GP group, 135 patients were referred to GPs (47 patients before the pandemic, 88 patients during the first peak of the pandemic; p = 0.023). Conclusion: Patient flow in the epilepsy care network changed as a result of the COVID-19 pandemic. These changes might present an opportunity to strengthen local interdisciplinary epilepsy care.

Evidence From Meta-Analysis Supports Ictal Magnetoencephalographic Source Imaging as an Accurate Method in Presurgery Evaluation of Patients With Drug-Resistant Epilepsy

BACKGROUND.

Successful epilepsy surgery relies on localization and removal of the brain area responsible for initializing the seizures called the epileptogenic zone (EZ). Intracranial EEG (icEEG) is gold standard of this localization but has several limitations like invasiveness and limited covered area. A noninvasive method with accurate localization precision is therefore desirable. The aim of this article is to investigate the following hypotheses: (1) Ictal onset zone as localized by magnetic source imaging (iMSI) can reliably localize the EZ in focal epilepsy and (2) this localization is as good as that of icEEG.

METHODS.

Six original studies and a total of 59 unique patients were included in a meta-analysis.

RESULTS.

Sensitivity and specificity of iMSI based on surgery outcome were 77% (95% CI 60%-90%) and 75% (95% CI 53%-90%), respectively. Specificity of iMSI was statistically higher than that of icEEG. There was no significant difference between sensitivity of iMSI and icEEG.

CONCLUSION.

The meta-analysis supports that iMSI is an accurate method, achieving similar sensitivity and higher specificity than icEEG. However, at present the use of the method is limited by short recording times. A limitation that might be overcome in the future using technical advances.

Postoperative persistent fever may be a risk factor for hydrocephalus in hemispherical disconnection surgery

INTRODUCTION

Hemispherical disconnection surgery such as hemispherotomy or posterior quadrant disconnection (PQD) surgery sometimes induces hydrocephalus. We postulated that some risk factors for postoperative hydrocephalus can be managed perioperatively. The purpose of this study was to clarify and statistically analyze perioperative risk factors for postoperative progressive hydrocephalus.

METHODS

We reviewed patients who underwent hemispherotomy or PQD. We compared patients with and without progressive hydrocephalus with multivariate and univariate logistic regression analysis to identify risk factors for hydrocephalus.

RESULTS

Twenty-four patients underwent hemispherectomy or PQD (age: 25 days-45 years old, mean: 13.3 years, median: 8 years, standard deviation: 13.9 years, 14 males). Among them, five patients (21%) required hydrocephalus treatment. Persistent fever was a risk factor for progressive hydrocephalus (multivariate analysis: p = 0.024, univariate analysis: p < 0.001).

CONCLUSION

Postoperative persistent fever may be a manageable risk factor for postoperative hydrocephalus in hemispherotomy and PQD surgery.

The association of cognitive phenotypes with postoperative outcomes after epilepsy surgery in patients with temporal lobe epilepsy

INTRODUCTION

The concept of cognitive phenotypes has been developed to categorize the heterogeneity of neuropsychological profiles in patients with temporal lobe epilepsy (TLE). This study examines the utility of cognitive phenotypes derived from clinical criteria in the prediction of postoperative outcomes.

METHODS

Scores from 9 standardized neuropsychological tests were used to sample preoperative performance in 4 core domains (intellectual, memory, language, & executive function) in 445 patients with TLE (206 right: 236 left). Patients were grouped into 3 clinical phenotypes using clinical criteria: 1. intact cognition, 2. isolated memory and/or language impairment, and 3. widespread impairment. Patients who did not meet the criteria for these phenotypes were characterized as having a mixed profile phenotype.

RESULTS

Approximately half of the sample had intact cognitive function, with one-quarter demonstrating isolated impairments in language and memory function. The remainder demonstrated widespread impairment or a mixed pattern of cognitive impairments. The clinically derived cognitive phenotypes were associated with demographic and clinical characteristics. Patients with widespread cognitive impairments had an earlier onset of seizures than those with other cognitive phenotypes. They also reported higher levels of depression. Higher levels of anxiety were reported in those with isolated memory/language impairments. Phenotypes were not associated with postoperative seizure outcome or postoperative declines in verbal memory or language function, but an intact phenotype was associated with a greater risk of decline in visual learning than right-sided surgery.

CONCLUSIONS

Distinct cognitive phenotypes in TLE can be identified using clinical criteria and may reflect neurodevelopmental influences and mood in addition to progression of the disease. Phenotype may be a more powerful predictor of postoperative decline in visual memory than laterality of surgery.

Diagnostic accuracy for the epileptogenic zone detection in focal epilepsy could be higher in FDG-PET/MRI than in FDG-PET/CT

OBJECTIVES

To examine the utility of FDG-PET/MRI in patients with epilepsy by comparing the diagnostic accuracy of PET/MRI and PET/CT in epileptogenic zone (EZ) detection.

METHODS

This prospective study included 31 patients (17 males, 14 females) who underwent surgical resection for EZ. All patients were first scanned using FDG-PET/CT followed immediately with FDG-PET/MRI. Two series of PET plus standalone MR images were interpreted independently by five board-certified radiologists. A 4-point visual score was used to assess image quality. Sensitivities and visual scores from both PETs and standalone MRI were compared using the McNemar test with Bonferroni correction and Dunn's multiple comparisons test.

RESULTS

The EZs were confirmed histopathologically via resection as hippocampal sclerosis (n = 11, 35.5%), gliosis (n = 8, 25.8%), focal cortical dysplasia (n = 6, 19.4%), and brain tumours (n = 6, 19.4%) including cavernous haemangioma (n = 3), dysembryoplastic neuroepithelial tumour (n = 1), ganglioglioma (n = 1), and polymorphous low-grade neuroepithelial tumour of the young (n = 1). The sensitivity of FDG-PET/MRI was significantly higher than that of FDG-PET/CT and standalone MRI (FDG-PET/MRI vs. FDG-PET/CT vs. standalone MRI; 77.4-90.3% vs. 58.1-64.5% vs. 45.2-80.6%, p < 0.0001, respectively). The visual scores derived from FDG-PET/MRI were significantly higher than those of FDG-PET/CT, as well as standalone MRI (2.8 ± 1.2 vs. 2.0 ± 1.1 vs. 2.1 ± 1.2, p < 0.0001, respectively). Compared to FDG-PET/CT, FDG-PET/MRI increased the visual score (51.9%, increased visual scores of 2 and 3).

CONCLUSIONS

The diagnostic accuracy for the EZ detection in focal epilepsy could be higher in FDG-PET/MRI than in FDG-PET/CT.

KEY POINTS

• Sensitivity of FDG-PET/MRI was significantly higher than that of FDG-PET/CT and standalone MRI (FDG-PET/MRI vs. FDG-PET/CT vs. standalone MRI; 77.4-90.3% vs. 58.1-64.5% vs. 45.2-80.6%, p < 0.0001, respectively). • Visual scores derived from FDG-PET/MRI were significantly higher than those of FDG-PET/CT and standalone MRI (2.8 ± 1.2 vs. 2.0 ± 1.1 vs. 2.1 ± 1.2, p < 0.0001, respectively). • Compared to FDG-PET/CT, FDG-PET/MRI increased the visual score (51.9%, increased visual scores of 2 and 3).

Modulation of epileptic networks by transient interictal epileptic activity: A dynamic approach to simultaneous EEG-fMRI

•

EEG-fMRI has been instrumental in characterizing brain networks in epilepsy.

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Its value is documented in the pre-surgical assessment of drug-resistant epilepsy.

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The delineation of brain areas to resect is fundamental for the post-surgical outcome.

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Standard EEG-fMRI in epilepsy assesses static functional connectivity of the network.

•

EEG-fMRI dynamic connectivity identifies transitory features of specific connections.

•

We integrate dynamic fMRI connectivity and dynamic patterns of simultaneous scalp EEG.

•

This allows to better characterize the spatiotemporal aspects of epileptic networks.

•

This may help in more efficiently target the surgical intervention.

Epileptic networks, defined as brain regions involved in epileptic brain activity, have been mapped by functional connectivity in simultaneous electroencephalography and functional magnetic resonance imaging (EEG-fMRI) recordings. This technique allows to define brain hemodynamic changes, measured by the Blood Oxygen Level Dependent (BOLD) signal, associated to the interictal epileptic discharges (IED), which together with ictal events constitute a signature of epileptic disease. Given the highly time-varying nature of epileptic activity, a dynamic functional connectivity (dFC) analysis of EEG-fMRI data appears particularly suitable, having the potential to identify transitory features of specific connections in epileptic networks. In the present study, we propose a novel method, defined dFC-EEG, that integrates dFC assessed by fMRI with the information recorded by simultaneous scalp EEG, in order to identify the connections characterised by a dynamic profile correlated with the occurrence of IED, forming the dynamic epileptic subnetwork. Ten patients with drug-resistant focal epilepsy were included, with different aetiology and showing a widespread (or multilobar) BOLD activation, defined as involving at least two distinct clusters, located in two different lobes and/or extended to the hemisphere contralateral to the epileptic focus. The epileptic focus was defined from the IED-related BOLD map. Regions involved in the occurrence of interictal epileptic activity; i.e., forming the epileptic network, were identified by a general linear model considering the timecourse of the fMRI-defined focus as main regressor. dFC between these regions was assessed with a sliding-window approach. dFC timecourses were then correlated with the sliding-window variance of the IED signal (VarIED), to identify connections whose dynamics related to the epileptic activity; i.e., the dynamic epileptic subnetwork. As expected, given the very different clinical picture of each individual, the extent of this subnetwork was highly variable across patients, but was but was reduced of at least 30% with respect to the initially identified epileptic network in 9/10 patients. The connections of the dynamic subnetwork were most commonly close to the epileptic focus, as reflected by the laterality index of the subnetwork connections, reported higher than the one within the original epileptic network. Moreover, the correlation between dFC timecourses and VarIED was predominantly positive, suggesting a strengthening of the dynamic subnetwork associated to the occurrence of IED. The integration of dFC and scalp IED offers a more specific description of the epileptic network, identifying connections strongly influenced by IED. These findings could be relevant in the pre-surgical evaluation for the resection or disconnection of the epileptogenic zone and help in reaching a better post-surgical outcome. This would be particularly important for patients characterised by a widespread pathological brain activity which challenges the surgical intervention.

Evolution of Surgical Management for Intractable Epileptic Spasms

The understanding and management of epileptic spasms has considerably evolved since the mid 19th century. The realization that epileptic spasms can be generated from a focal brain lesion played a pivotal role in the development of neurosurgical management for intractable forms of this epilepsy. During pre-surgical planning, the addition of functional FDG PET imaging has further refined the electroencephalographic localization of epileptogenic lesions. In some cases, neurosurgical resection of a focus that is co-localized by the FDG PET scan and electroencephalography can lead to partial or complete reversal of developmental delay along with reduced seizure frequency or seizure freedom. In cases where near-complete hemispheric cortex is implicated in spasm generation, subtotal hemispherectomy has shown encouraging results. Moreover, palliative resection of the major perpetrating focus in carefully chosen patients with bilateral multifocal spasms has also led to favorable outcomes. However, in patients with tuberous sclerosis with high tuber burden, the localizing value of FDG PET imaging may be limited. In such cases, employment of AMT PET technology has become a valuable tool for localization of actively epileptogenic tubers. This article highlights the historic steps in the successful advancements of neurosurgical interventions for the treatment of intractable epileptic spasms.

Removal of Interictal MEG-Derived Network Hubs Is Associated With Postoperative Seizure Freedom

Objective: To investigate whether MEG network connectivity was associated with epilepsy duration, to identify functional brain network hubs in patients with refractory focal epilepsy, and assess if their surgical removal was associated with post-operative seizure freedom. Methods: We studied 31 patients with drug refractory focal epilepsy who underwent resting state magnetoencephalography (MEG), and structural magnetic resonance imaging (MRI) as part of pre-surgical evaluation. Using the structural MRI, we generated 114 cortical regions of interest, performed surface reconstruction and MEG source localization. Representative source localized signals for each region were correlated with each other to generate a functional brain network. We repeated this procedure across three randomly chosen one-minute epochs. Network hubs were defined as those with the highest intra-hemispheric mean correlations. Post-operative MRI identified regions that were surgically removed. Results: Greater mean MEG network connectivity was associated with a longer duration of epilepsy. Patients who were seizure free after surgery had more hubs surgically removed than patients who were not seizure free (AUC = 0.76, p = 0.01) consistently across three randomly chosen time segments. Conclusion: Our results support a growing literature implicating network hub involvement in focal epilepsy, the removal of which by surgery is associated with greater chance of post-operative seizure freedom.

Epilepsy surgery for pediatric patients with mild malformation of cortical development

PURPOSE

The observation of mild malformation of cortical development (mMCD) has yet to have a major clinical impact due to the lack of clinical and research data. We characterized the clinical features, surgical outcomes, and postoperative seizure control patterns in pediatric patients with mMCD.

METHODS

We examined 40 patients with isolated mMCD who underwent resective surgery during a 10-year period.

RESULTS

The median age at seizure onset was 1.2 years, and the median age at surgery was 7.9 years. Twenty-seven patients (67.5%) presented with childhood-onset epileptic encephalopathy (21 Lennox-Gastaut syndrome, 6 West syndrome), and 13 patients (32.5%) presented with intractable focal epilepsy (10 extratemporal lesions, 3 temporal lesions). Twenty-one patients (52.5%) showed "suspected focal cortical malformation" on MRI, whereas 16 patients (40.0%) and 3 patients (7.5%) showed normal MRI findings or mild brain atrophy, respectively. The most common surgical procedures were two lobar resections (18 patients, 45.0%), followed by unilobar resections (12 patients, 30.0%) and resections exceeding two lobar boundaries (10 patients, 25.0%). As a final surgical outcome, 24 patients (60.0%) were ILAE Class 1-3. Discontinuation of all AEDs was possible for 36.8% of ILAE Class 1 patients. Regarding the seizure control pattern, fluctuating seizure control was observed most frequently (21 patients, 52.5%).

CONCLUSION

Our results suggest that mMCD is an important pathological finding in children related to a significant degree of epileptogenicity, and resective surgery can have positive outcomes. However, these patients showed unstable postoperative seizure control patterns with a high rate of late recurrence, suggesting difficulties in the surgical treatment of intractable epilepsy.

Odor identification predicts postoperative seizure control following magnetic resonance-guided laser interstitial thermal therapy

OBJECTIVE

Olfactory dysfunction has been well documented in individuals with temporal lobe epilepsy, but its use in presurgical planning has yet to be examined. We assessed the role of preoperative odor identification in mesial onset seizure localization utilizing stereoelectroencephalography (S-EEG) and magnetic resonance-guided laser interstitial thermal therapy (MRgLiTT) outcome.

METHODS

We identified 30 patients who had typical seizures captured during S-EEG monitoring or MRgLiTT of mesial temporal structures (n = 17 S-EEG, n = 13 MRgLiTT); seizure onset zone was classified as unilateral mesial seizure onset, or multifocal with unilateral mesial onset and nonmesial onset. Odor identification ability was assessed using the Sniffin' Sticks Odor Identification Test (SSOIT). Patients also completed measures of confrontation naming and auditory-verbal learning/memory using the Boston Naming Test and Hopkins Verbal Learning Test-Revised, respectively.

RESULTS

Overall, patients with intractable focal epilepsy exhibited poor olfactory performance (median [M] = 10.4, interquartile range [IQR] = 9.4-11.8). Of 19 patients who underwent MRgLiTT, 10 patients (52.6%) were seizure-free at last follow-up (M = 13 months, IQR =10-18). Patients who were seizure-free after MRgLiTT (n = 10) had poorer odor identification scores (M = 9, IQR = 7-13) compared to patients with seizure reoccurrence (M = 13, IQR = 12.5-15). Odor identification score was inversely associated with seizure freedom, with odds ratio = 0.60 (95% confidence interval [CI] = 0.38-0.95, P = .03). Receiver operating characteristic analysis revealed that an SSOIT score of 12 was the ideal cutoff for predicting favorable seizure outcome (area under the curve = 0.84, 95% CI = 0.64-1.0). Sensitivity was 88.9% and specificity was 78.9%, with a likelihood ratio of 2.9 of seizure failure in patients who had an odor identification score ≥ 12.

SIGNIFICANCE

Interictal olfactory dysfunction is commonly seen in patients with intractable focal epilepsy. Odor identification is a novel, noninvasive presurgical biomarker to distinguish who may or may not benefit from MRgLiTT of mesial temporal structures.

Frontal disconnection surgery for drug-resistant epilepsy: Outcome in a series of 16 patients

OBJECTIVE

To evaluate the effectiveness of frontal disconnection surgery in seizure control and related consequences in a consecutive patient series.

METHODS

We conducted a retrospective analysis of patients who underwent frontal disconnection surgery for drug-resistant epilepsy (DRE). Baseline epilepsy characteristics, detailed presurgical evaluation including epileptogenic zone (EZ) localization, magnetic resonance imaging (MRI) detection of epileptogenic lesion, and pathological findings were reviewed. Patients were followed postoperatively for seizure outcome at 1 year.

RESULTS

A total of 16 patients were identified (six children and 10 adults). Most patients had a childhood onset of DRE with a median duration of epilepsy of 6.5 years (interquartile range 3.5-17.5 years) before surgery. In 10 (62.5%) patients, the EZ was localized to the frontal lobe, while in six patients, the EZ involved also adjacent lobes or consisted of multiple foci. In 10 (62.5%) patients, an epileptogenic lesion was detected on presurgical MRI, four of which (40%) had all MRI abnormalities confined to the frontal lobe. Two-thirds of the patients (11/16; 68.8%) underwent isolated frontal disconnection procedure, while remaining patients had frontal disconnection combined with resection of an adjacent lobe. Of the 12 patients in whom biopsy was taken from the disconnected frontal lobe, six (50%) had pathology-proven focal cortical dysplasia. We observed surgical-related complications in three (18.8%) cases, neurological deficits in other three (18.8%) patients, and worsening cognitive abilities in one (6.3%) patient. Overall, eight (50%) patients became completely seizure-free (ILAE 1) at one-year follow-up.

SIGNIFICANCE

Frontal disconnection surgery for DRE can result in seizure freedom in certain patients, especially when the EZ is strictly limited to the ipsilateral frontal region, and the MRI shows an epileptogenic lesion that is purely frontal in location. Frontal lobe disconnection procedure is safe and has a limited complication rate. However, further studies with larger patient population will yield more significance.

Seizure outcome and use of antiepileptic drugs after epilepsy surgery according to histopathological diagnosis: a retrospective multicentre cohort study

BACKGROUND

Surgery is a widely accepted treatment option for drug-resistant focal epilepsy. A detailed analysis of longitudinal postoperative seizure outcomes and use of antiepileptic drugs for different brain lesions causing epilepsy is not available. We aimed to analyse the association between histopathology and seizure outcome and drug freedom up to 5 years after epilepsy surgery, to improve presurgical decision making and counselling.

METHODS

In this retrospective, multicentre, longitudinal, cohort study, patients who had epilepsy surgery between Jan 1, 2000, and Dec 31, 2012, at 37 collaborating tertiary referral centres across 18 European countries of the European Epilepsy Brain Bank consortium were assessed. We included patients of all ages with histopathology available after epilepsy surgery. Histopathological diagnoses and a minimal dataset of clinical variables were collected from existing local databases and patient records. The primary outcomes were freedom from disabling seizures (Engel class 1) and drug freedom at 1, 2, and 5 years after surgery. Proportions of individuals who were Engel class 1 and drug-free were reported for the 11 main categories of histopathological diagnosis. We analysed the association between histopathology, duration of epilepsy, and age at surgery, and the primary outcomes using random effects multivariable logistic regression to control for confounding.

FINDINGS

9147 patients were included, of whom seizure outcomes were available for 8191 (89·5%) participants at 2 years, and for 5577 (61·0%) at 5 years. The diagnoses of low-grade epilepsy associated neuroepithelial tumour (LEAT), vascular malformation, and hippocampal sclerosis had the best seizure outcome at 2 years after surgery, with 77·5% (1027 of 1325) of patients free from disabling seizures for LEAT, 74·0% (328 of 443) for vascular malformation, and 71·5% (2108 of 2948) for hippocampal sclerosis. The worst seizure outcomes at 2 years were seen for patients with focal cortical dysplasia type I or mild malformation of cortical development (50·0%, 213 of 426 free from disabling seizures), those with malformation of cortical development-other (52·3%, 212 of 405 free from disabling seizures), and for those with no histopathological lesion (53·5%, 396 of 740 free from disabling seizures). The proportion of patients being both Engel class 1 and drug-free was 0-14% at 1 year and increased to 14-51% at 5 years. Children were more often drug-free; temporal lobe surgeries had the best seizure outcomes; and a longer duration of epilepsy was associated with reduced chance of favourable seizure outcomes and drug freedom. This effect of duration was evident for all lesions, except for hippocampal sclerosis.

INTERPRETATION

Histopathological diagnosis, age at surgery, and duration of epilepsy are important prognostic factors for outcomes of epilepsy surgery. In every patient with refractory focal epilepsy presumed to be lesional, evaluation for surgery should be considered.

FUNDING

None.

'In the best case seizure-free' - Parental hopes and worries before and satisfaction after their child's epilepsy surgery

OBJECTIVE

The objective of this study was to gain a better understanding of parental hopes and worries before and subsequent experiences two years after their child had undergone epilepsy surgery.

METHODS

The parents of 107 children and young people who underwent epilepsy surgery at a single center completed surveys focusing on hopes and concerns before surgery and subsequent experiences at two-year follow-up. Responses were analyzed by thematic analysis.

RESULTS

Before surgery, parental hopes focus on not only seizure freedom or reduction but also potential improvements in child development and emotional-behavioral functioning. Worries before surgery include not only potential injury or loss of skills but also a concern that the surgical procedure would not lead to an improvement in the child's seizures. The vast majority of parents experienced positive aspects at the two-year follow-up including seizure freedom or reduction but also perceived improvements in behavior, development, and sleep. This suggests that for many, expectations for the surgery were met. A small number of parents reported negative effects of surgery including loss of skills, worsening/lack of improvement in seizure frequency, or negative impact on development.

SIGNIFICANCE

For the majority of parents whose children undergo surgery, expectations are met, and fears are not realized. Knowledge of parental hopes and worries before surgery as well as experiences after the operation is useful for improving pre- and postsurgical counseling.

Development and Evaluation of a Caregiver Reported Quality of Life Assessment Instrument in Dogs With Intracranial Disease

In veterinary medicine, quality of life (QOL) assessment instruments, which are important components of the holistic evaluation of treatment success, have largely not included organ-specific concerns that may be broadly relevant to caregivers of dogs with intracranial disease. The objective of this study was to identify core questionnaire items and domains that contribute to health-related QOL (HRQOL) in dogs with intracranial disease. A questionnaire was developed that contained 39 QOL-related items encompassing physical, social/companionship, and brain-specific domains associated with the treatment of dogs with intracranial disease, and administered to caregivers of 56 dogs diagnosed with genetic, inflammatory, neoplastic, traumatic, and vascular brain diseases, 52 healthy dogs, and 20 dogs with non-neurological illnesses. Clinician derived functional measures of each dog's health status including chronic pain, Karnofsky performance, and modified Glasgow coma scale scores were also recorded. Principal component analysis refined the final questionnaire, termed the CanBrainQOL-24, to 24-items within the three domains with a minimum Cronbach's alpha of 0.7, indicative of good internal consistency. The CanBrainQOL-24 discriminated between healthy and diseased dogs. Physical and brain-specific domains were significantly different between dogs with intracranial and non-neurological diseases. Significant correlations were observed between owner reported visual analog scores and CanBrainQOL-24 scores, as well between clinician derived functional status measures and owner reported QOL. The CanBrainQOL-24 contains core questions relevant to caregiver assessment of HRQOL in dogs with a variety of intracranial diseases, and provides information that is complementary to clinician derived functional outcome measures.

Oblique trajectory angles in robotic stereo-electroencephalography

OBJECTIVE

Traditional stereo-electroencephalography (sEEG) entails the use of orthogonal trajectories guided by seizure semiology and arteriography. Advances in robotic stereotaxy and computerized neuronavigation have made oblique trajectories more feasible and easier to implement without formal arteriography. Such trajectories provide access to components of seizure networks not readily sampled using orthogonal trajectories. However, the dogma regarding the relative safety and predictability of orthogonal and azimuth-based trajectories persists, given the absence of data regarding the safety and efficacy of oblique sEEG trajectories. In this study, the authors evaluated the relative accuracy and efficacy of both orthogonal and oblique trajectories during robotic implantation of sEEG electrodes to sample seizure networks.

METHODS

The authors performed a retrospective analysis of 150 consecutive procedures in 134 patients, accounting for 2040 electrode implantations. Of these, 837 (41%) were implanted via oblique trajectories (defined as an entry angle > 30°). Accuracy was calculated by comparing the deviation of each electrode at the entry and the target point from the planned trajectory using postimplantation imaging.

RESULTS

The mean entry and target deviations were 1.57 mm and 1.89 mm for oblique trajectories compared with 1.38 mm and 1.69 mm for orthogonal trajectories, respectively. Entry point deviation was significantly associated with entry angle, but the impact of this relationship was negligible (-0.015-mm deviation per degree). Deviation at the target point was not significantly affected by the entry angle. No hemorrhagic or infectious complications were observed in the entire cohort, further suggesting that these differences were not meaningful in a clinical context. Of the patients who then underwent definitive procedures after sEEG, 69 patients had a minimum of 12 months of follow-up, of whom 58 (84%) achieved an Engel class I or II outcome during a median follow-up of 27 months.

CONCLUSIONS

The magnitude of stereotactic errors in this study falls squarely within the range reported in the sEEG literature, which primarily features orthogonal trajectories. The patient outcomes reported in this study suggest that seizure foci are well localized using oblique trajectories. Thus, the selective use of oblique trajectories in the authors' cohort was associated with excellent safety and efficacy, with no patient incidents, and the findings support the use of oblique trajectories as an effective and safe means of investigating seizure networks.

Trends in the use of automated algorithms for the detection of high-frequency oscillations associated with human epilepsy

High-frequency oscillations (HFOs) in intracranial electroencephalography (EEG) are a promising biomarker of the epileptogenic zone and tool for surgical planning. Many studies have shown that a high rate of HFOs (number per minute) is correlated with the seizure-onset zone, and complete removal of HFO-generating brain regions has been associated with seizure-free outcome after surgery. In order to use HFOs as a biomarker, these transient events must first be detected in electrophysiological data. Because visual detection of HFOs is time-consuming and subject to low interrater reliability, many automated algorithms have been developed, and they are being used increasingly for such studies. However, there is little guidance on how to select an algorithm, implement it in a clinical setting, and validate the performance. Therefore, we aim to review automated HFO detection algorithms, focusing on conceptual similarities and differences between them. We summarize the standard steps for data pre-processing, as well as post-processing strategies for rejection of false-positive detections. We also detail four methods for algorithm testing and validation, and we describe the specific goal achieved by each one. We briefly review direct comparisons of automated algorithms applied to the same data set, emphasizing the importance of optimizing detection parameters. Then, to assess trends in the use of automated algorithms and their potential for use in clinical studies, we review evidence for the relationship between automatically detected HFOs and surgical outcome. We conclude with practical recommendations and propose standards for the selection, implementation, and validation of automated HFO-detection algorithms.

Can REM Sleep Localize the Epileptogenic Zone? A Systematic Review and Analysis

Epilepsy is a common and debilitating neurological disease. When medication cannot control seizures in up to 40% of cases, surgical resection of epileptogenic tissue is a clinically and cost- effective therapy to achieve seizure freedom. To simultaneously resect minimal yet sufficient cortex, exquisite localization of the epileptogenic zone (EZ) is crucial. However, localization is not straightforward, given relative difficulty of capturing seizures, constraints of the inverse problem in source localization, and possible disparate locations of symptomatogenic vs. epileptogenic regions. Thus, attention has been paid to which state of vigilance best localizes the EZ, in the hopes that one or another sleep-wake state may hold the key to improved accuracy of localization. Studies investigating this topic have employed diverse methodologies and produced diverse results. Nonetheless, rapid eye movement sleep (REM) has emerged as a promising sleep-wake state, as epileptic phenomena captured in REM may spatially correspond more closely to the EZ. Cortical neuronal asynchrony in REM may spatially constrain epileptic phenomena to reduce propagation away from the source generator, rendering them of high localizing value. However, some recent work demonstrates best localization in sleep-wake states other than REM, and there are reports of REM providing clearly false localization. Moreover, synchronistic properties and basic mechanisms of human REM remain to be fully characterized. Amidst these uncertainties, there is an urgent need for recording and analytical techniques to improve accuracy of localization. Here we present a systematic review and quantitative analysis of pertinent literature on whether and how REM may help localize epileptogenic foci. To help streamline and accelerate future work on the intriguing anti-epileptic properties of REM, we also introduce a simple, conceptually clear set-theoretic framework to conveniently and rigorously describe the spatial properties of epileptic phenomena in the brain.

Surgical treatment in children with intractable epilepsy after viral encephalitis

PURPOSE

To investigate the surgical outcome in children with epilepsy after viral encephalitis (VE), we studied the prognostic factors for surgery and summarized the surgical strategies of children with epilepsy secondary to VE.

METHODS

We retrospectively analyzed 23 surgically treated children with VE. The subjects were divided into two groups according to their surgical outcome. All presurgical evaluation data were collected and analyzed.

RESULTS

Among the 23 operated children, the mean age at surgery was 6.1 years. Surgeries were hemispherotomy (n = 12), temporal-parietal-occipital disconnection (n = 4), whole corpus callosotomy (n = 3), lobectomy (n = 3), and vagus nerve stimulation (n = 1). The mean patient follow-up time was 37.2 months, and 13 children had a good outcome (ILAE classification 1-3). Univariate analyses revealed that the latency from infection to the first unprovoked seizure, MRI laterality, concordance of PET and MRI abnormalities, and acute postoperative seizure (APOS) were prognostic factors of seizure outcomes (P < 0.05). No correlation was found between generalized seizures and poor outcome (P = 0.229).

CONCLUSIONS

We concluded that the children who achieve favorable surgical outcomes are those with longer latency, unilateral abnormalities on MRI, consistency of PET and MRI abnormalities, and no APOS. Without invasive studies, epilepsy surgery may be successful for selected children with epilepsy after VE, despite diffuse interictal epileptiform discharges on scalp EEG. In addition, children with generalized seizures were not an absolute contraindication for surgery.

Predictive value of electrically induced seizures for postsurgical seizure outcome

OBJECTIVE

To determine whether semiological similarity of electrically induced seizures (EIS) and spontaneously occurring habitual seizures (SHS) is associated with postsurgical seizure outcome in patients undergoing invasive video-EEG monitoring (VEM) before resective epilepsy surgery.

METHODS

Data of patients undergoing invasive VEM were retrospectively reviewed and included if at least one EIS and SHS during VEM occurred and the brain region in which EIS were elicited was resected. Seizure outcome was evaluated at three follow-up (FU) visits after surgery (1, 2 years and last available FU) according to the classification by Engel and the International League Against Epilepsy (ILAE). The level of semiological similarity of EIS and SHS was rated blinded to the surgical outcome. Statistics were done using Fisher's exact test and a mixed linear-logistic regression model.

RESULTS

65 patients were included. Postsurgical seizure freedom was achieved in 51% (ILAE class 1) and 58% (Engel class I) at last FU (median 36 months). Patients with identical EIS and SHS displayed significantly better postsurgical seizure outcomes (ILAE class 1 at last FU: 76% vs. 31%, p < 0.001; Engel class I: 83% vs. 39%, p < 0.001).

CONCLUSION

EIS are useful to confirm the location of the epileptogenic zone. A high level of similarity between EIS and SHS is associated with a favorable postsurgical seizure outcome.

SIGNIFICANCE

EIS may be used as an additional predictor of postsurgical outcome when counselling patients to proceed to resective epilepsy surgery.

Drebrin expression patterns in patients with refractory temporal lobe epilepsy and hippocampal sclerosis

OBJECTIVE

Drebrins are crucial for synaptic function and dendritic spine development, remodeling, and maintenance. In temporal lobe epilepsy (TLE) patients, a significant hippocampal synaptic reorganization occurs, and synaptic reorganization has been associated with hippocampal hyperexcitability. This study aimed to evaluate, in TLE patients, the hippocampal expression of drebrin using immunohistochemistry with DAS2 or M2F6 antibodies that recognize adult (drebrin A) or adult and embryonic (pan-drebrin) isoforms, respectively.

METHODS

Hippocampal sections from drug-resistant TLE patients with hippocampal sclerosis (HS; TLE, n = 33), of whom 31 presented with type 1 HS and two with type 2 HS, and autopsy control cases (n = 20) were assayed by immunohistochemistry and evaluated for neuron density, and drebrin A and pan-drebrin expression. Double-labeling immunofluorescences were performed to localize drebrin A-positive spines in dendrites (MAP2), and to evaluate whether drebrin colocalizes with inhibitory (GAD65) and excitatory (VGlut1) presynaptic markers.

RESULTS

Compared to controls, TLE patients had increased pan-drebrin in all hippocampal subfields and increased drebrin A-immunopositive area in all hippocampal subfields but CA1. Drebrin-positive spine density followed the same pattern as total drebrin quantification. Confocal microscopy indicated juxtaposition of drebrin-positive spines with VGlut1-positive puncta, but not with GAD65-positive puncta. Drebrin expression in the dentate gyrus of TLE cases was associated negatively with seizure frequency and positively with verbal memory. TLE patients with lower drebrin-immunopositive area in inner molecular layer (IML) than in outer molecular layer (OML) had a lower seizure frequency than those with higher or comparable drebrin-immunopositive area in IML compared with OML.

SIGNIFICANCE

Our results suggest that changes in drebrin-positive spines and drebrin expression in the dentate gyrus of TLE patients are associated with lower seizure frequency, more preserved verbal memory, and a better postsurgical outcome.

Network reorganisation following anterior temporal lobe resection and relation with post-surgery seizure relapse: A longitudinal study

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Diffusion changes assessed at two time points following epilepsy surgery.

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Graph theory and connectometry revealed substantial longitudinal diffusion changes.

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Changes were found beyond the site of resection.

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Postoperative seizure freedom associated with longitudinal structural changes.

Objective

To characterise temporal lobe epilepsy (TLE) surgery-induced changes in brain network properties, as measured using diffusion weighted MRI, and investigate their association with postoperative seizure-freedom.

Methods

For 48 patients who underwent anterior temporal lobe resection, diffusion weighted MRI was acquired pre-operatively, 3–4 months post-operatively (N = 48), and again 12 months post-operatively (N = 13). Data for 17 controls were also acquired over the same period. After registering all subjects to a common space, we performed two complementary analyses of the subjects’ quantitative anisotropy (QA) maps. 1) A connectometry analysis which is sensitive to changes in subsections of fasciculi. 2) A graph theory approach which integrates connectivity information across the wider brain network.

Results

We found significant postoperative alterations in QA in patients relative to controls measured over the same period. Reductions were primarily located in the uncinate fasciculus and inferior fronto-occipital fasciculus ipsilaterally for all patients. Larger reductions were associated with postoperative seizure-freedom in left TLE. Increased QA was mainly located in corona radiata and corticopontine tracts. Graph theoretic analysis revealed widespread increases in nodal betweenness centrality, which were not associated with patient outcomes.

Conclusion

Substantial alterations in QA occur in the months after epilepsy surgery, suggesting Wallerian degeneration and strengthening of specific white matter tracts. Greater reductions in QA were related to postoperative seizure freedom in left TLE.

Neuropsychological outcomes after pediatric epilepsy surgery: Role of electrical stimulation language mapping

PURPOSE

We studied the association between electrical stimulation mapping (ESM) with a visual naming task and post-operative neuropsychological outcomes after pediatric epilepsy surgery.

METHODS

Children who underwent epilepsy surgery, having pre- and 1-year post-surgery neuropsychological evaluation (NPE) available, were included. NPE scores were transformed using principal components (PC) analysis. The relationship between post-surgical PC scores, adjusted for pre-surgery PC scores, and ESM was analyzed. Clinical variables influencing this relationship were also sought.

RESULTS

One hundred and four children (89 patients >5 years-old, and 15 patients 3-5 years-old) were included. Among children >5 years-of-age, a significant effect of language ESM was observed on all 3 post-surgery PC scores adjusted for respective pre-surgery PC scores. Specifically, only 30 % patients who underwent language ESM had a decrease in PC1 scores ≥1-year after epilepsy surgery, compared to 68 % those who did not undergo language ESM (p = 0.001). Seizure outcomes, age at the time of surgery, predominant seizure type, and family history of epilepsy were other significant determinants of post-surgical PC scores including a change in PC scores from pre-surgery baseline. Combinations of pre-surgical variables were able to predict post-surgical PC scores with high specificity. In children aged 3-5 years, no significant effect of language ESM was seen on post-surgery PC scores adjusted for respective pre-surgery PC scores.

CONCLUSIONS

Speech/language ESM should be performed more widely in patients >5 years-of-age undergoing epilepsy surgery. Also, more efficient brain mapping techniques and language paradigms are needed for younger children.

Alterations in GABAA Receptor Subunit Expression in the Amygdala and Entorhinal Cortex in Human Temporal Lobe Epilepsy

The amygdala has long been implicated in the pathophysiology of human temporal lobe epilepsy (TLE). The different nuclei of this complex structure are interconnected and share reciprocal connections with the hippocampus and other brain structures, partly via the entorhinal cortex. Expression of GABAA receptor subunits α1, α2, α3, α5, β2, β2/3, and γ2 was evaluated by immunohistochemistry in amygdala specimens and the entorhinal cortex of 12 TLE patients and 12 autopsy controls. A substantial decrease in the expression of α1, α2, α3, and β2/3 subunits was found in TLE cases, accompanied by an increase of γ2 subunit expression in many nuclei. In the entorhinal cortex, the expression of all GABAA receptor subunits was decreased except for the α1 subunit, which was increased on cellular somata. The overall reduction in α subunit expression may lead to decreased sensitivity to GABA and its ligands and compromise phasic inhibition, whereas upregulation of the γ2 subunit might influence clustering and kinetics of receptors and impair tonic inhibition. The description of these alterations in the human amygdala is important for the understanding of network changes in TLE as well as the development of subunit-specific therapeutic agents for the treatment of this disease.

Parents' and children's decision-making and experiences in pediatric epilepsy surgery

BACKGROUND

In pediatric epilepsy surgery, little research has been conducted on parents' decision-making for or against surgery, their satisfaction with the surgical outcome, as well as their children's personal experiences with the process.

OBJECTIVE

This study explores (1) factors that may influence parents' decision-making, (2) factors associated with their postoperative satisfaction, and (3) their children's involvement in decision-making and their experiences with epilepsy surgery.

METHODS

Self-developed questionnaires were provided to parents and their children in Germany, Switzerland, and Austria. Clinical and psychosocial differences between parents who decided for or against surgery, as well as associations between postoperative factors and the parents' satisfaction were statistically analyzed.

RESULTS

Fifty-one questionnaires (42 parent and nine patient questionnaires) were evaluated. Parents who decided for epilepsy surgery reported significantly more frequently to have received a good medical consultation and a consistent recommendation. They made significantly less use of information websites, internet forums, and patient organizations. Their children were classified as more intelligent and resisted surgery less. Most of the parents were satisfied with the surgical outcome (83%). Parents were significantly more satisfied when their children had fewer medication side effects, their memory or concentration had improved, their character or behavior had changed in a positive direction, or when their children were more independent or less excluded. They were also significantly more content when they had more free time to themselves and their professional situation or their relationship with their children, friends, or other family members had improved. However, no significant association was found between parental satisfaction and reduced number of medications or improved seizure outcome. Although the children were reported to have been minimally involved in the decision-making process, they were satisfied with their involvement.

CONCLUSIONS

A good medical consultation that involves the children and considers the family's living conditions is a crucial factor for parents' decision-making on pediatric epilepsy surgery. For parents' satisfaction, a positive change in their child's character or behavior and an improved psychosocial situation of the family are more important than postoperative seizure frequency or number of antiepileptic drugs (AEDs). Therefore, the medical consultation should not only focus on clinical factors, but also point out psychosocial and behavioral changes that may occur after the surgical treatment.

Functional hemispherectomy: can preoperative imaging predict outcome?

OBJECTIVE

Although hemispherectomy is an effective treatment for children with intractable hemispheric epilepsy syndromes, as many as 40% of patients eventually develop seizure recurrence. The causes of seizure recurrence in these patients are incompletely understood. The authors sought to evaluate the efficacy of hemispherectomy at their center and determine whether contralateral MRI abnormalities can predict seizure recurrence.

METHODS

A retrospective review of consecutive hemispherectomies performed at Miami Children's Hospital between January 2000 and June 2014 was performed. Time-to-event analysis was performed. The "event" was defined as any seizures following resective epilepsy surgery (not including seizures in the first postoperative week and auras). Several preoperative variables were analyzed to determine their suitability to predict seizure recurrence following surgery.

RESULTS

Sixty-nine patients (44 boys) with a mean age of 8.2 ± 5.9 years (range 0.1-20.8 years) underwent 72 hemispherectomies; 67 of these were functional hemispherectomies, while another 5 were completion of a previous functional hemispherectomy (2 completions of functional hemispherectomies, 3 anatomical hemispherectomies). The duration of epilepsy was 5.8 ± 5.5 years with 66 cases (91.7%) having daily seizures. Etiology included stroke (n = 28), malformation of cortical development (n = 11), hemimegalencephaly (n = 11), encephalitis (n = 13), and other (n = 7). Engel class I outcome was achieved in 59 (86%) and 56 (81%) patients at 1 and 2 years of follow-up, respectively. The mean time to seizure recurrence was 33.5 ± 31.1 months. In univariate analyses, the absence of contralateral abnormalities on MRI (HR 4.09, 95% CI 1.41-11.89, p = 0.009) was associated with a longer duration of seizure freedom. The presence of contralateral MRI abnormalities was associated with contralateral ictal seizures on preoperative scalp EEG (p = 0.002). Fifteen patients experienced 20 complications (20/72, 27.8%), including the development of hydrocephalus necessitating CSF diversion in 9 cases (13%), hygroma in 1, hemispheric edema in 1, aseptic meningitis in 2, postoperative hemorrhage in 2, infection in 2, ischemic stroke in 2, and blood transfusion-contracted hepatitis C in 1 case.

CONCLUSIONS

Patients with bihemispheric abnormalities, as evidenced by contralateral MRI abnormalities, have a higher risk of earlier seizure recurrence following functional hemispherectomy.

ABBREVIATIONS

EVD = external ventricular drain; MCD = malformation of cortical development; MEG = magnetoencephalography; PVWM = periventricular white matter; TTE = time-to-event; VPS = ventriculoperitoneal shunt.

Frontal lobe epilepsy with focal neuronal lipofuscinosis - Case report of a rare entity

Focal neuronal lipofuscinosis is a unique neuronal pathology, characterised by accumulation of lipofuscin within dysmorphic neurons. We report a case of 12-year-old female with drug resistant epilepsy since one and a half years of age. MRI brain showed right frontal dysplasia, and PET showed right frontal hypometabolism. She underwent electrocorticography-guided resection of the lesion. Histopathology revealed cortical dyslamination with several hypertrophic dysmorphic neurons showing intracytoplasmic granular accumulation of lipofuscin which was positive for Periodic acid–Schiff, Luxol fast blue, and autofluorescent. Ultrastructural examination revealed intracytoplasmic, non-membrane bound, electron dense material with characteristics of lipofuscin filling the neuronal soma. On immunohistochemistry, the neurons showed ring-like non-phosphorylated and phosphorylated neurofilaments enveloping the lipofuscin material, few being positive for ubiquitin. It is important to be aware of this rare entity as it can be associated with family history of seizures and has a distinct pathobiology.

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Focal neuronal lipofuscinosis, a newly described entity, is a rare cause of frontal lobe epilepsy mimicking focal cortical dysplasia.

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Histology and ultrastructure reveal accumulation of lipofuscin within dysmorphic neurons, attributed to enhanced autophagy.

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It has a variable clinical outcome and may be associated with family history of seizures.

Virtual resection predicts surgical outcome for drug-resistant epilepsy

Patients with drug-resistant epilepsy often require surgery to become seizure-free. While laser ablation and implantable stimulation devices have lowered the morbidity of these procedures, seizure-free rates have not dramatically improved, particularly for patients without focal lesions. This is in part because it is often unclear where to intervene in these cases. To address this clinical need, several research groups have published methods to map epileptic networks but applying them to improve patient care remains a challenge. In this study we advance clinical translation of these methods by: (i) presenting and sharing a robust pipeline to rigorously quantify the boundaries of the resection zone and determining which intracranial EEG electrodes lie within it; (ii) validating a brain network model on a retrospective cohort of 28 patients with drug-resistant epilepsy implanted with intracranial electrodes prior to surgical resection; and (iii) sharing all neuroimaging, annotated electrophysiology, and clinical metadata to facilitate future collaboration. Our network methods accurately forecast whether patients are likely to benefit from surgical intervention based on synchronizability of intracranial EEG (area under the receiver operating characteristic curve of 0.89) and provide novel information that traditional electrographic features do not. We further report that removing synchronizing brain regions is associated with improved clinical outcome, and postulate that sparing desynchronizing regions may further be beneficial. Our findings suggest that data-driven network-based methods can identify patients likely to benefit from resective or ablative therapy, and perhaps prevent invasive interventions in those unlikely to do so.

Semiologic subgroups of insulo-opercular seizures based on connectional architecture atlas

OBJECTIVE

Insulo-opercular seizures are characterized by diverse semiology, related to the insula's multiple functional roles and extensive connectivity. We aimed to identify semiologic subgroups and correlate these with insulo-opercular subregions based on connectional architecture.

METHODS

We retrospectively collected a large series of 37 patients with insulo-opercular seizures explored by stereoelectroencephalography (SEEG) from three epilepsy centers. A new human brain atlas (Brainnetome Atlas, BNA) based on both anatomic and functional connections was employed to segment insulo-opercular cortex. Semiology and SEEG changes were carefully reviewed and quantified. Principal component analysis and cluster analysis were used to correlate semiologic characteristics with insulo-opercular subregions.

RESULTS

Four main semiologic subgroups were identified, organized along an anteroventral to posterodorsal axis based on BNA. Group 1 was characterized by epigastric sensation and/or integrated gestural motor behaviors with or without feelings of fear or rage, involving the anteroventral insular regions and mesial temporal lobes. Group 2 was characterized by auditory sensations and symmetric proximal/axial tonic signs involving the posteroventral temporal operculum. The characteristics of group 3 were orofacial and laryngeal signs, involving the intermediate insulo-opercular regions. The features of group 4 were somatosensory signs followed by nonintegrated gestural motor behaviors and/or asymmetric tonic signs involving the posterodorsal insulo-opercular regions with propagation to the mesial frontal lobes. Thus anteroventral seizure organizations predominantly showed limbic system semiology, whereas more posterodorsal regions were associated with semiology involving mainly the sensorimotor system. Subjective symptoms proved to be particularly discriminating factors.

SIGNIFICANCE

Insulo-opercular seizures can be categorized in terms of clinical semiology and correlate with connectional architecture subregions along an anteroventral-posterodorsal axis in line with the cytoarchitectonic gradient rather than the gyral anatomy of the insula cortex. This provides new insights into facilitating differential diagnosis and presurgical localization but also highlights the importance of considering connectional architecture in determining neural correlates of complex semiologic patterns.

Stereotactic radiofrequency thermocoagulation and resective surgery for patients with hypothalamic hamartoma

OBJECTIVE

In this study, the authors compared the efficacy and safety of stereotactic radiofrequency thermocoagulation (SRT) and resective surgery (RS) for patients with hypothalamic hamartoma (HH).

METHODS

The authors included all patients with HHs who were treated by SRT or hamartoma resection. Seizure outcomes were assessed by blinded observers according to the International League Against Epilepsy (ILAE) classification. Favorable seizure outcomes were defined as ILAE classes 1 and 2, and unfavorable seizure outcomes were defined as ILAE classes 3-6.

RESULTS

Twenty-nine patients who underwent SRT or RS met the inclusion criteria; 3 were excluded because they had completed less than 12 months of follow-up. Most of the patients (20 of 26; 76.9%) had small HHs (i.e., maximum HH diameter less than 20 mm). The patients' follow-up time ranged from 12 to 66 months (median 60 months). At the last follow-up, favorable outcomes were observed in 9 patients (69.2%) who had undergone SRT and 10 patients (76.9%) who had undergone HH resection. No significant difference was found in seizure outcomes between SRT and RS recipients. Patients with giant HHs were more likely than patients with smaller tumors to undergo multiple resections (p = 0.043, univariate logistic regression; significant). However, no significant difference was found between SRT and RS recipients in terms of the number of procedures per patient. SRT recipients had fewer and less-severe adverse events than RS recipients.

CONCLUSIONS

For patients with small HHs, SRT provides similar seizure outcomes to RS with a less invasive procedure. Patients who underwent SRT experienced fewer and lighter adverse effects than patients who had RS. Patients with giant HHs were more likely to undergo multiple HH resections.

Stereotactic laser interstitial thermal therapy for epilepsy associated with solitary and multiple cerebral cavernous malformations

OBJECTIVE

The authors sought to perform a preliminary assessment of the safety and effectiveness of stereotactic laser interstitial thermal therapy (LITT) for patients with cerebral cavernous malformation (CCM)–related epilepsy.

METHODS

The authors retrospectively analyzed 6 patients with CCM-related epilepsy who underwent LITT. Pre-, intra-, and postoperative brain MRI studies were used to characterize preoperative CCM volume, ablation volume, and postablation hemosiderin volume. Clinical outcomes were assessed postoperatively during clinic follow-up visits or phone interviews.

RESULTS

LITT was performed in 7 CCMs in 6 patients. Two patients had familial CCM disease with multifocal lesions. Four treated CCMs were extratemporal, and 3 were in or near the visual pathways. The median follow-up was 25 (range 12–39) months. Five of 6 (83%) patients achieved seizure freedom (Engel I classification), of whom 4 (67%) were Engel IA and 1 was Engel IC after a single seizure on postoperative day 4. The remaining patient had rare seizures (Engel II). One patient had a nondisabling visual field deficit. There were no hemorrhagic complications. All patients were discharged within 24 hours postablation. MRI 3–11 months after ablation demonstrated expected focal necrosis and trace hemosiderin-related T2 hypointensity measuring 9%–44% (median 24%) of the original lesion volume, with significant (p = 0.04) volume reduction.

CONCLUSIONS

LITT is a minimally invasive option for treating CCM-related epilepsy with seizure outcomes comparable to those achieved with open lesionectomy. The precision of LITT allows for the obliteration of eloquent, deep, small, and multifocal lesions with low complication rates, minimal postoperative discomfort, and short hospital stays. In this study the feasibility and benefits of this method were demonstrated in 2 patients with multifocal lesions.

Prognostic factors of postoperative seizure outcomes in older patients with temporal lobe epilepsy

OBJECTIVE

The authors of this study aimed to investigate surgical outcomes and prognostic factors in older patients with drug-resistant temporal lobe epilepsy (TLE) who had undergone resective surgery.

METHODS

Data on patients older than 45 years of age with drug-resistant TLE who had undergone resective surgery at Sanbo Brain Hospital, Capital Medical University, between January 2009 and August 2017 were retrospectively collected. Postoperative seizure outcomes were evaluated according to the International League Against Epilepsy (ILAE) classification. Patients belonging to ILAE classes 1 and 2 were classified as having a favorable outcome, whereas patients belonging to ILAE classes 3-6 were classified as having an unfavorable outcome. Univariate analysis and multivariate logistic regression analysis were used to identify the potential predictors of seizure outcomes.

RESULTS

A total of 45 patients older than 45 years of age who had undergone resective epilepsy surgery for TLE were included in the present study. Eight (17.8%) of 45 patients had preoperative comorbidity in addition to seizures. The average age at the time of surgery was 51.76 years, and the average duration of epilepsy at the time surgery was 18.01 years. After an average follow-up period of 4.53 ± 2.82 years (range 2-10 years), 73.3% (33/45) of patients were seizure free. Surgical complications were observed in 13.3% of patients. Univariate and multivariate analyses revealed that an MRI-negative finding is the only independent predictor of unfavorable seizure outcomes (OR 0.06, 95% CI 0.01-0.67, p = 0.023).

CONCLUSIONS

Resective surgery is a safe and effective treatment for older patients with drug-resistant TLE. An MRI-negative finding independently predicts unfavorable seizure outcomes.

Efficacy and Safety of Epilepsy Surgery for Older Adult Patients with Refractory Epilepsy

Purpose

The population of elderly patients with epilepsy has been growing rapidly and the chances of referring older patients with refractory epilepsy for surgical options could be increasing. In general, epilepsy surgery at higher ages has been less likely to be performed, because little is known regarding the risks and benefits in elderly patients. We, therefore, investigated surgical outcomes and comorbidities in a population ≥50 years old who underwent epilepsy surgery.

Methods

Patients ≥50 years old who underwent epilepsy surgery were identified from the database of our epilepsy center for the period from 2009 to 2017. Surgical complications and seizure outcome were reviewed, and seizure outcomes were evaluated using the International League Against Epilepsy (ILAE) surgery outcome scale.

Results

The mean age of 32 patients at the time of surgery was 56.1±5.1 years. The mean duration of epilepsy was 23.4±18.5 years and mean follow-up was 2.7±2.0 years. As of the most recent visit, 56.3% of patients remained completely seizure-free (ILAE Class I). The surgery-related complication rate was 11.5%, comprising permanent deficits in 3.8% and transient deficits in 7.7%.

Conclusion

These results suggest that epilepsy surgery may represent a valuable approach in selected adult patients.

Subsecond EEG-fMRI analysis for presurgical evaluation in focal epilepsy

OBJECTIVE

The authors recently reported a novel subsecond analysis method of analyzing EEG-functional MRI (fMRI) to improve the detection rate of epileptic focus. This study aims to validate the utility of this method for presurgical evaluation in pharmacoresistant focal epilepsy.

METHODS

Among 13 patients with focal epilepsy undergoing presurgical examinations including simultaneous EEG-fMRI at 3T, 11 patients had interictal epileptiform discharges (IEDs) during fMRI. The authors used the sequence of topographic maps during the IEDs as a reference to obtain subsecond fMRI activation maps with the same temporal resolution as the EEG data, and constructed "spike-and-slow-wave-activation-summary" (SSWAS) maps that showed the activation frequency of voxels during IEDs. Clusters were defined by thresholding the SSWAS maps (voxel value > 10), and those containing voxels with the top 3 highest activation frequencies were considered significant. Significant hemodynamic responses using conventional event-related (ER) analysis and SSWAS maps were compared with the resection areas and surgical outcomes at 1 year after surgery.

RESULTS

Using ER analysis, 4 (36%) of 11 patients had significant hemodynamic responses. One of 4 patients had significant hemodynamic responses in the resection area and good surgical outcome. Using SSWAS maps, 10 (91%) of 11 patients had significant hemodynamic responses. Six of 10 patients had significant hemodynamic responses in the resection area, and 5 of the 6 patients achieved good surgical outcomes. The remaining 4 patients had significant hemodynamic responses distant from the resection area, and only 1 of the 4 patients achieved good surgical outcomes. The sensitivity, specificity, positive predictive value, and negative predictive value of SSWAS maps were 83.3%, 75.0%, 83.3%, and 75.0%, respectively.

CONCLUSIONS

This study demonstrated the clinical utility of SSWAS maps for presurgical evaluation of pharmacoresistant focal epilepsy. The findings indicated that subsecond EEG-fMRI analysis may help surgeons choose the resection areas that could lead to good surgical outcomes.

Novel Deep Learning Network Analysis of Electrical Stimulation Mapping-Driven Diffusion MRI Tractography to Improve Preoperative Evaluation of Pediatric Epilepsy

OBJECTIVE

To investigate the clinical utility of deep convolutional neural network (DCNN) tract classification as a new imaging tool in the preoperative evaluation of children with focal epilepsy (FE).

METHODS

A DCNN tract classification deeply learned spatial trajectories of DWI white matter pathways linking electrical stimulation mapping (ESM) findings from 89 children with FE, and then automatically identified white matter pathways associated with eloquent functions (i.e., primary motor, language, and vision). Clinical utility was examined by 1) measuring the nearest distance between DCNN-determined pathways and ESM, 2) evaluating the effectiveness of DCNN-determined pathways to optimize surgical margins via Kalman filter analysis, and 3) evaluating how accurately changes in DCNN-determined language pathway volume can predict changes in language ability via canonical correlation analysis.

RESULTS

DCNN tract classification outperformed other existing methods, achieving an excellent accuracy of 98 % while non-invasively detecting eloquent areas within the spatial resolution of ESM (i.e., 1 cm). The Kalman filter analysis found that the preservation of brain areas within a surgical margin determined by DCNN tract classification predicted lack of postoperative deficit with a high accuracy of 92 %. Postoperative change of DCNN-determined language pathway volume showed a significant correlation with postoperative changes in language ability (R = 0.7, p   0.001).

CONCLUSION

Our findings demonstrate that postoperative functional deficits substantially differ according to the extent of resected white matter, and that DCNN tract classification may offer key translational information by identifying these pathways in pediatric epilepsy surgery.

SIGNIFICANCE

DCNN tract classification may be an effective tool to improve surgical outcome of children with FE.

Predicting outcome of epilepsy surgery in clinical practice: Prediction models vs. clinical acumen

PURPOSE

Epilepsy surgery is an evidence-based treatment for drug-refractory focal epilepsy. We aimed to evaluate how well preoperative outcome estimates of epilepsy surgery in clinical practice correlated with postoperative outcome and to compare prediction by the clinical team with available scores (m-SFS, ESN).

METHOD

Retrospective cohort study including patients with drug-refractory focal epilepsy who underwent resective epilepsy surgery at Epilepsy Center Hessen, Marburg, between 1998-2016. Patients were categorized into four groups based on their estimated chance of postoperative seizure freedom documented in preoperative medical records. Variables required for calculation of m-SFS and ESN were also extracted from presurgical medical records. Seizure outcome using Engel/ILAE classifications was extracted from postoperative medical records.

RESULTS

148 patients were included and 98 had follow-up at 5 years. 69 (70%) had Engel I and 50 (51%) ILAE 1 outcome. Observed 5-year outcome for very good candidates was 20/22 (91%) Engel I and 14/22 (64%) ILAE 1, for good candidates 29/40 (73%) Engel I and 21/40 (53%) ILAE 1, for candidates with slightly reduced chance 11/18 (61%) Engel I and 9/18 (50%) ILAE 1 and for candidates with considerably reduced chance 1/5 (20%) Engel I and 1/5 (20%) ILAE 1.There were no significant differences in discrimination or overall performance between predictions by the clinical team, ESN and m-SFS.

CONCLUSIONS

Preoperative outcome estimates corresponded well with observed outcome indicating adequate patient counseling.

Long-Term Cognitive Improvement After Functional Hemispherectomy

BACKGROUND

To investigate intellectual development after functional hemispherectomy and to evaluate the favorable or unfavorable factors affecting prognosis.

METHODS

Twenty-three patients from the patient follow-up database of the Epilepsy Center of Neurosurgery were selected for this retrospective study. The inclusion criteria of the patients were functional hemispherectomy surgery, surgical age older than 6 years, patients able to complete the intelligence assessment, follow-up time not less than 2 years, and availability of complete preoperative evaluation and postoperative follow-up data. Full Scale Intelligence Quotients (FSIQ) were calculated preoperatively and at the follow-up times for each patient. Correlations between the preoperative to postoperative changes in FSIQ and risk factors (age at epilepsy onset, duration of preoperative epilepsy, postoperative changes in the electroencephalogram, seizure status after surgery, and follow-up time) were analyzed. EpiData 3.1 software was used to establish a database and SPSS 22.0 software was used for data collation and analysis, and used the matching sample Wilcoxon symbol rank and test to conduct the analysis.

RESULTS

The data of 23 patients were analyzed. The final follow-up results showed that 73.9% of the patients (17/23) had a significant increase in FSIQ scores (P = 0.006) after surgery, indicating that their cognitive function improved significantly. Successful surgery, successful postoperative seizure control, normalization of postoperative electroencephalogram, shorter disease duration before surgery, and longer recovery periods after surgery (follow-up time) were all related with good intellectual prognosis.

CONCLUSIONS

Successful functional hemispherectomy significantly improved the cognitive function of patients. Functional hemispherectomy is a safe and effective treatment for patients with intractable epilepsy caused by hemispheric lesions and can effectively promote intellectual recovery and development.

Optimizing Management of Medically Responsive Epilepsy

PURPOSE OF REVIEW

This article reviews the management of patients with medically responsive epilepsy, including discussion of factors that may lead to transient breakthrough seizures and patient and physician strategies to maintain freedom from seizures.

RECENT FINDINGS

Imperfect adherence, unanticipated changes in ongoing medical therapy, inadvertent use of proconvulsants or concurrent medications that alter epilepsy medication kinetics, and a variety of seizure precipitants such as stress or sleep deprivation may alter long-term seizure control.

SUMMARY

The majority of patients with epilepsy are medically responsive. Many potential factors may lead to breakthrough seizures in these patients. Identification of these factors, patient education, and use of self-management techniques including mindfulness therapy and cognitive-behavioral therapy may play a role in protecting patients with epilepsy against breakthrough seizures.

Quantitative analysis of intracranial electrocorticography signals using the concept of statistical parametric mapping

Statistical parametric mapping (SPM) is a technique with which one can delineate brain activity statistically deviated from the normative mean, and has been commonly employed in noninvasive neuroimaging and EEG studies. Using the concept of SPM, we developed a novel technique for quantification of the statistical deviation of an intracranial electrocorticography (ECoG) measure from the nonepileptic mean. We validated this technique using data previously collected from 123 patients with drug-resistant epilepsy who underwent resective epilepsy surgery. We determined how the measurement of statistical deviation of modulation index (MI) from the non-epileptic mean (rated by z-score) improved the performance of seizure outcome classification model solely based on conventional clinical, seizure onset zone (SOZ), and neuroimaging variables. Here, MI is a summary measure quantifying the strength of in-situ coupling between high-frequency activity at >150 Hz and slow wave at 3-4 Hz. We initially generated a normative MI atlas showing the mean and standard deviation of slow-wave sleep MI of neighboring non-epileptic channels of 47 patients, whose ECoG sampling involved all four lobes. We then calculated 'MI z-score' at each electrode site. SOZ had a greater 'MI z-score' compared to non-SOZ in the remaining 76 patients. Subsequent multivariate logistic regression analysis and receiver operating characteristic analysis to the combined data of all patients revealed that the full regression model incorporating all predictor variables, including SOZ and 'MI z-score', best classified the seizure outcome with sensitivity/specificity of 0.86/0.76. The model excluding 'MI z-score' worsened its sensitivity/specificity to 0.86/0.48. Furthermore, the leave-one-out analysis successfully cross-validated the full regression model. Measurement of statistical deviation of MI from the non-epileptic mean on invasive recording is technically feasible. Our analytical technique can be used to evaluate the utility of ECoG biomarkers in epilepsy presurgical evaluation.

Parent reported health related quality of life (HRQoL) and behaviour in young people with epilepsy before and two years after epilepsy surgery

PURPOSE

The aim of this study was to compare parent-reported Health Related Quality of Life (HRQoL) and behaviour of young people before (baseline) and two years after paediatric epilepsy surgery (follow-up).

METHODS

The parents of 107 children who underwent epilepsy surgery completed surveys focussing on different aspects of child HRQoL and behaviour at baseline and follow-up. Parents of children with multiple disabilities (n = 27) completed five additional questions focussing on child HRQoL. Changes in scores between baseline and follow-up were compared using Wilcoxon signed-rank tests. Factors associated with changes in scores were analyzed using linear regression.

RESULTS

HRQoL and behaviour were significantly improved at follow-up (p < 0.001). HRQoL was also significantly improved for children with multiple disabilities (p = 0.003). Factors independently associated with improvement in HRQoL on multivariable analysis were lower baseline scores (p < 0.001), seizure-free status (p < 0.001) and improvement in behaviour (p = 0.022). Factors independently associated with improvement in behaviour were higher baseline difficulties (p < 0.001), reduction in antiepileptic drug (AED) usage, (p < 0.001), seizure-free status (p = 0.04), younger age (p = 0.03), and improvements in HRQoL (p = 0.028).

CONCLUSION

Parent rated HRQoL and behaviour had improved two years after epilepsy surgery. Seizure freedom was associated with both improvements in HRQoL and behaviour. Additionally, a reduction in AED usage contributed to reduced behavioural difficulties. All children undergoing epilepsy surgery should undergo assessment of HRQoL and behaviour at baseline and follow-up.

Altered Expression of Astrocyte-Related Receptors and Channels Correlates With Epileptogenesis in Hippocampal Sclerosis

BACKGROUND

Hippocampal sclerosis (HS) is one of the major causes of intractable epilepsy. Astrogliosis in epileptic brain is a peculiar condition showing epileptogenesis and is thought to be different from the other pathological conditions. The aim of this study is to investigate the altered expression of astrocytic receptors, which contribute to neurotransmission in the synapse, and channels in HS lesions.

METHODS

We performed immunohistochemical and immunoblotting analyses of the P2RY1, P2RY2, P2RY4, Kir4.1, Kv4.2, mGluR1, and mGluR5 receptors and channels with the brain samples of 20 HS patients and 4 controls and evaluated the ratio of immunopositive cells and those expression levels.

RESULTS

The ratio of each immunopositive cell per glial fibrillary acidic protein-positive astrocytes and the expression levels of all 7 astrocytic receptors and channels in HS lesions were significantly increased. We previously described unique astrogliosis in epileptic lesions similar to what was observed in this study.

CONCLUSION

This phenomenon is considered to trigger activation of the related signaling pathways and then contribute to epileptogenesis. Thus, astrocytes in epileptic lesion may show self-hyperexcitability and contribute to epileptogenesis through the endogenous astrocytic receptors and channels. These findings may suggest novel astrocytic receptor-related targets for the pharmacological treatment of epilepsy.

Is intracranial electroencephalography useful for planning resective surgery in intractable epilepsy with ulegyria?

OBJECTIVE

Intractable epilepsy patients with ulegyria could be candidates for resective surgery. Complete resection of ulegyria in the epileptogenic hemisphere is associated with favorable seizure outcome, although the risk of postoperative functional deficits is higher. The authors evaluated the extent of resection and postsurgical outcomes in epilepsy patients with ulegyria who underwent intracranial electroencephalography (iEEG) monitoring prior to resection to clarify the efficacy of iEEG-guided partial resection of ulegyria.

METHODS

Ten consecutive epilepsy patients with ulegyria (7 males and 3 females, age range at surgery 7-34 years) underwent iEEG prior to resective surgery between 2011 and 2017 with a minimum follow-up of 12 months (range 12-72 months). The diagnosis of ulegyria was based on the typical pattern of cortical atrophy especially at the bottom of the sulcus on MRI. An iEEG study was indicated after comprehensive preoperative evaluations, including high-field MRI, long-term video-EEG, magnetoencephalography, and FDG-PET. The resection planning was based on iEEG analysis. Total lesionectomy was not always performed, as preservation of cortical function was prioritized.

RESULTS

Ulegyria was seen in the occipital and/or parietal lobe in 9 patients and bilaterally in 5 patients. Ictal EEG onset involved the temporal neocortex in 6 patients. Intracranial electrodes were implanted unilaterally in all except 1 patient with bilateral lesions. The extent of MRI lesion was covered by the electrodes. Seizure onset zones (SOZs) and irritative zones (IZs) were identified in all patients. SOZs and IZs were completely resected in 8 patients but were only partially removed in the remaining 2 patients because the eloquent cortices and the epileptogenic zones overlapped. Ulegyria of the epileptogenic side was totally resected in 1 patient. Seizure freedom was achieved in 4 patients, including 3 after partial lesionectomy. Extended resection of the temporal neocortex was performed in 4 patients, although postoperative seizure freedom was achieved only in 1 of these patients. Visual field deficit was seen in 4 patients. Three of 5 patients with bilateral lesions achieved seizure freedom after unilateral resective surgery.

CONCLUSIONS

Intracranial EEG-guided partial lesionectomy provides a reasonable chance of postoperative seizure freedom with a lower risk of functional deficits. Patients with bilateral ulegyria should not be excluded from consideration as surgical candidates.

Chronic post-encephalitic epilepsy following Japanese encephalitis: Clinical features, neuroimaging data, and outcomes

PURPOSE

Japanese encephalitis (JE), the main cause of viral encephalitis in Asia, usually presents with acute symptomatic seizures; however, there have been very few systematic reports regarding late unprovoked seizures and epilepsy. We aimed to describe the clinical features and outcomes of post-encephalitic epilepsy following JE.

METHODS

Patients with epilepsy with a previous confirmed diagnosis of JE visiting West China Hospital from 2013 to 2019 were enrolled in the observational case-controlled study. Patients with epilepsy with a history of other non-specific viral encephalitis were enrolled as controls. For all enrolled subjects, disease related information was recorded.

RESULTS

Forty-eight patients with JE (20 males; median age, 21.0 years; average epilepsy duration, 8.55 years) were identified. The median duration from JE to the first unprovoked seizure was 7.73 years, which significantly differed from that of the controls (7.73 vs. 2.69 years, respectively; p = 4.59 × 10^-6). Most patients had focal epilepsy, and 29 (78.38%) were drug resistant. Among 45 patients with available neuroimaging data, three in fourth had no obvious abnormality, and the temporal lobe and hippocampus (22.22%) were the most affected brain regions. Six patients had surgery, and three achieved class-one seizure-free status.

CONCLUSION

The latency to the first unprovoked seizure was longer in patients with JE than controls. Regarding chronic epilepsy, three in four had structural abnormalities, and the long-term outcomes of post-encephalitic epilepsy following JE were poor. Surgery remains an option for drug-resistant epilepsy.

Preoperative tumor-associated epilepsy in patients with supratentorial meningioma: factors influencing seizure outcome after meningioma surgery

OBJECTIVE

Both pre- and postoperative seizures comprise common side effects that negatively impact patient quality of life in those suffering from intracranial meningioma. Therefore, seizure freedom represents an important outcome measure in meningioma surgery. In the current study the authors analyzed their institutional database to identify risk factors for postoperative seizure occurrence after surgical meningioma therapy in patients with preoperative symptomatic epilepsy.

METHODS

Between February 2009 and April 2017, 187 patients with preoperative seizures underwent resection of supratentorial meningioma at the authors' institution. Seizure outcome was assessed retrospectively 12 months after tumor resection according to the International League Against Epilepsy (ILAE) classification and stratified into favorable (ILAE class I) versus unfavorable (ILAE classes II-VI). A univariate and multivariate analysis was performed to identify factors influencing seizure outcome.

RESULTS

Overall 169 (90%) of 187 patients with preoperative seizures achieved favorable outcome in terms of seizure freedom after meningioma resection. Multivariate analysis revealed peritumoral edema > 1 cm in maximal diameter and WHO grade II and III tumors, as well as a low extent of resection (Simpson grades III-V) as independent predictors for postoperative unfavorable seizure outcome.

CONCLUSIONS

Surgery is highly effective in the treatment of seizures as common side effects of supratentorial meningioma. Furthermore, the present study identified several significant and independent risk factors for postoperative seizure occurrence, enabling one to select for high-risk patients that require special attention in clinical and surgical management.

Resective surgery for drug-resistant posttraumatic epilepsy: predictors of seizure outcome

OBJECTIVE

The object of this study was to evaluate surgical outcomes and prognosis factors in patients with drug-resistant posttraumatic epilepsy (PTE) who had undergone resective surgery.

METHODS

The authors retrospectively reviewed the records of all patients with drug-resistant PTE who had undergone resective surgery at Sanbo Brain Hospital, Capital Medical University, in the period from January 2008 to December 2016. All patients had a follow-up period of at least 2 years. Seizure outcomes were evaluated according to the International League Against Epilepsy (ILAE) classification. Patients in ILAE classes 1 and 2 during the last 2 years of follow-up were classified as having a favorable outcome; patients in all other classes were considered to have an unfavorable outcome. Univariate analysis and a multivariate logistic regression model in a backward fashion were used to identify the potential predictors of seizure outcomes.

RESULTS

Among 90 patients with a follow-up of 2-10 years (mean ± standard deviation, 5.79 ± 2.84 years), 70% (63 patients) were seizure free, of whom 68.9% (62 patients) had an ILAE class 1 outcome and 1.1% (1 patient) had an ILAE class 2 outcome. Permanent neurological deficits were observed in 10 patients (11.1%). Univariate and multivariate analyses revealed that only the duration of seizures ≤ 8 years was an independent predictor of a favorable seizure outcome (OR 0.34, 95% CI 0.13-0.92).

CONCLUSIONS

Resective surgery is an effective treatment for patients with drug-resistant PTE with an acceptable incidence of complications. The information on prognosis factors suggests that early surgery may offer more benefits to patients with drug-resistant PTE.