Detection of focal to bilateral tonic-clonic seizures using a connected shirt.

OBJECTIVE: This study was undertaken to develop and evaluate a machine learning-based algorithm for the detection of focal to bilateral tonic-clonic seizures (FBTCS) using a novel multimodal connected shirt. METHODS: We prospectively recruited patients with epilepsy admitted to our epilepsy monitoring unit and asked them to wear the connected shirt while under simultaneous video-electroencephalographic monitoring. Electrocardiographic (ECG) and accelerometric (ACC) signals recorded with the connected shirt were used for the development of the seizure detection algorithm. First, we used a sliding window to extract linear and nonlinear features from both ECG and ACC signals. Then, we trained an extreme gradient boosting algorithm (XGBoost) to detect FBTCS according to seizure onset and offset annotated by three board-certified epileptologists. Finally, we applied a postprocessing step to regularize the classification output. A patientwise nested cross-validation was implemented to evaluate the performances in terms of sensitivity, false alarm rate (FAR), time in false warning (TiW), detection latency, and receiver operating characteristic area under the curve (ROC-AUC). RESULTS: We recorded 66 FBTCS from 42 patients who wore the connected shirt for a total of 8067 continuous hours. The XGBoost algorithm reached a sensitivity of 84.8% (56/66 seizures), with a median FAR of .55/24 h and a median TiW of 10 s/alarm. ROC-AUC was .90 (95% confidence interval = .88-.91). Median detection latency from the time of progression to the bilateral tonic-clonic phase was 25.5 s. SIGNIFICANCE: The novel connected shirt allowed accurate detection of FBTCS with a low false alarm rate in a hospital setting. Prospective studies in a residential setting with a real-time and online seizure detection algorithm are required to validate the performance and usability of this device.

Novel NALCN variant linked to temporal lobe epilepsy.

The sodium leak channel (NALCN) gene encodes a sodium leak channel that plays an important role in the regulation of the resting membrane potential and the control of neuronal excitability. Mutations in the NALCN gene have been reported in patients with infantile hypotonia with psychomotor retardation and characteristic facies (IHPRF) and congenital contractures of the limbs and face with hypotonia and developmental delay (CLIFAHDD syndrome). We describe the case of a father with drug-resistant left temporo-orbitofrontal epilepsy and his son with mildly-symptomatic temporal epilepsy (only recurrent déjà vu auras) whose genetic panels identified a likely pathogenic deletion of exon 27 on the NALCN gene. Our study helps broaden the clinical spectrum of diseases associated with mutations in the NALCN gene.

Usage of Genetic Panels in an Adult Epilepsy Clinic.

BACKGROUND: There is limited data on the utility, yield, and cost efficiency of genetic testing in adults with epilepsy. We aimed to describe the yield and utility of genetic panels in our adult epilepsy clinic. METHODS: We performed a retrospective, cross-sectional study of all patients followed by an epileptologist at a Canadian tertiary care centre's epilepsy clinic between January 2016 and August 2021 for whom a genetic panel was ordered. A panel was generally ordered when the etiology was unknown or in the presence of a malformation of cortical development. We determined the yield of panel positivity and of confirmed genetic diagnoses. We also estimated the proportion of these diagnoses that were clinically actionable. RESULTS: In total, 164 panels were ordered in 164 patients. Most had refractory epilepsy (80%), and few had comorbid intellectual disability (10%) or a positive family history of epilepsy (11%). The yield of panel positivity was 11%. Panel results were uncertain 49% of the time and negative 40% of the time. Genetic diagnoses were confirmed in 7 (4.3%) patients. These genetic conditions involved the following genes: SCARB2, DEPDC5, PCDH19, LGI1, SCN1A, MT-TL1, and CHRNA7. Of the seven genetic diagnoses, 5 (71%) were evaluated to be clinically actionable. CONCLUSION: We report a lower diagnostic yield for genetic panels in adults with epilepsy than what has so far been reported. Although the field of the genetics of epilepsy is a fast-moving one and more data is required, our findings suggest that guidelines for genetic testing in adults are warranted.

Epilepsy and Pregnancy: An Audit of Specialized Care.

BACKGROUND: Caring for women with epilepsy (WWE) during pregnancy poses unique challenges. We conducted an audit of the care our epilepsy clinic provided to pregnant WWE. METHODS: We performed a retrospective study on all pregnancies followed by an epileptologist at a Canadian tertiary care centre's epilepsy clinic between January 2003 and March 2021. Among 81 pregnancies in 53 patients, 72 pregnancies in 50 patients were analyzed to determine patient-related, follow-up-related, antiseizure-medication-related, and child-related pregnancy characteristics. Univariate analyses were performed to explore if these characteristics were associated with disabling seizure occurrence during pregnancy. RESULTS: Most pregnancies were intended (72%) and occurred in women who used folic acid pre-pregnancy (76%) and who followed recommended blood tests for antiseizure medication (ASM) levels (71%). In 49% of pregnancies, ASM dosage was modified; 53% of these modifications were made in response to ASM blood levels. Most often used ASMs were lamotrigine (43%), followed by carbamazepine (32%) and levetiracetam (13%). One child was born with a thyroglossal duct cyst; our congenital malformation rate was thus 2%. Disabling seizures occurred in 24% of pregnancies. Exploratory analyses suggested that disabling seizure occurrence during pregnancy was associated with younger patient age (p = 0.018), higher number of ASMs used during pregnancy (p = 0.048), lamotrigine usage in polytherapy (p = 0.008), and disabling seizure occurrence pre-pregnancy (p = 0.027). CONCLUSION: This Canadian audit provides an in-depth description of pregnancies benefiting from specialized epilepsy care. Our results suggest an association between disabling seizure occurrence during pregnancy and lamotrigine usage in polytherapy that warrants further evaluation.

Intervention Time and Adverse Events in a Canadian Epilepsy Monitoring Unit.

BACKGROUND: Intervention time (IT) in response to seizures and adverse events (AEs) have emerged as key elements in epilepsy monitoring unit (EMU) management. We performed an audit of our EMU, focusing on IT and AEs. METHODS: We performed a retrospective study on all clinical seizures of admissions over a 1-year period at our Canadian academic tertiary care center's EMU. This EMU was divided in two subunits: a daytime three-bed epilepsy department subunit (EDU) supervised by EEG technicians and a three-bed neurology ward subunit (NWU) equipped with video-EEG where patients were transferred to for nights and weekends, under nursing supervision. Among 124 admissions, 58 were analyzed. A total of 1293 seizures were reviewed to determine intervention occurrence, IT, and AE occurrence. Seizures occurring when the staff was present at bedside at seizure onset were analyzed separately. RESULTS: Median IT was 21.0 (11.0-40.8) s. The EDU, bilateral tonic-clonic seizures (BTCS), and the presence of a warning signal were associated with increased odds of an intervention taking place. The NWU, BTCS, and seizure rank (seizures were chronologically ordered by the patient for each subunit) were associated with longer ITs. Bedside staff presence rate was higher in the EDU than in the NWU (p < 0.001). AEs occurred in 19% of admissions, with no difference between subunits. AEs were more frequent in BTCS than in other seizure types (p = 0.001). CONCLUSION: This study suggests that close monitoring by trained staff members dedicated to EMU patients is key to optimize safety. AE rate was high, warranting corrective measures.

Variants in CHRNB2 and CHRNA4 Identified in Patients with Insular Epilepsy.

PURPOSE: Our purpose was to determine the role of CHRNA4 and CHRNB2 in insular epilepsy. METHOD: We identified two patients with drug-resistant predominantly sleep-related hypermotor seizures, one harboring a heterozygous missense variant (c.77C>T; p. Thr26Met) in the CHRNB2 gene and the other a heterozygous missense variant (c.1079G>A; p. Arg360Gln) in the CHRNA4 gene. The patients underwent electrophysiological and neuroimaging studies, and we performed functional characterization of the p. Thr26Met (c.77C>T) in the CHRNB2 gene. RESULTS: We localized the epileptic foci to the left insula in the first case (now seizure-free following epilepsy surgery) and to both insulae in the second case. Based on tools predicting the possible impact of amino acid substitutions on the structure and function of proteins (sorting intolerant from tolerant and PolyPhen-2), variants identified in this report could be deleterious. Functional expression in human cell lines of α4ß2 (wild-type), α4ß2-Thr26Met (homozygote), and α4ß2/ß2-Thr26Met (heterozygote) nicotinic acetylcholine receptors revealed that the mutant subunit led to significantly higher whole-cell nicotinic currents. This feature was observed in both homo- and heterozygous conditions and was not accompanied by major alterations of the current reversal potential or the shape of the concentration-response relation. CONCLUSIONS: This study suggests that variants in CHRNB2 and CHRNA4, initially linked to autosomal dominant nocturnal frontal lobe epilepsy, are also found in patients with predominantly sleep-related insular epilepsy. Although the reported variants should be considered of unknown clinical significance for the moment, identification of additional similar cases and further functional studies could eventually strengthen this association.

Utility of magnetic source imaging in nonlesional focal epilepsy: a prospective study.

OBJECTIVE: For patients with nonlesional refractory focal epilepsy (NLRFE), localization of the epileptogenic zone may be more arduous than for other types of epilepsy and frequently requires information from multiple noninvasive presurgical modalities and intracranial EEG (icEEG). In this prospective, blinded study, the authors assessed the clinical added value of magnetic source imaging (MSI) in the presurgical evaluation of patients with NLRFE. METHODS: This study prospectively included 57 consecutive patients with NLRFE who were considered for epilepsy surgery. All patients underwent noninvasive presurgical evaluation and then MSI. To determine the surgical plan, discussion of the results of the presurgical evaluation was first undertaken while discussion participants were blinded to the MSI results. MSI results were then presented. MSI influence on the initial management plan was assessed. RESULTS: MSI results influenced patient management in 32 patients. MSI results led to the following changes in surgical strategy in 14 patients (25%): allowing direct surgery in 6 patients through facilitating the detection of subtle cortical dysplasia in 4 patients and providing additional concordant diagnostic information to other presurgical workup in another 2 patients; rejection of surgery in 3 patients originally deemed surgical candidates; change of plan from direct surgery to icEEG in 2 patients; and allowing icEEG in 3 patients deemed not surgical candidates. MSI results led to changed electrode locations and contact numbers in another 18 patients. Epilepsy surgery was performed in 26 patients influenced by MSI results and good surgical outcome was achieved in 21 patients. CONCLUSIONS: This prospective, blinded study showed that information provided by MSI allows more informed icEEG planning and surgical outcome in a significant percentage of patients with NLRFE and should be included in the presurgical workup in those patients.

Le magnésium et le calcium réduisent la sévérité des troubles de la mémoire spatiale pour le modèle kaïnique d'épilepsie mésiale temporale chez la souris.

Calcium and magnesium are divalent multipotent ions playing a major role in metabolism, excitability and neuroglial plasticity. Because of these multiple properties, their deficiency induces complex brain processes leading to acute or even lasting disorders in excitability and neural networks. These ions are usually prescribed in clinical contexts of neuronal hyperexcitability such as preeclampsia and chronic stress. Our aim was to evaluate whether magnesium at 20 mg/kg and calcium at 100 mg/kg could improve the memory prognosis in the kainic model of mesial temporal epilepsy in mice. The animals were organized into 6 groups: control group (without kainate), reference group (GR) without administration of ions, groups treated with magnesium or calcium from the third day (respectively G1m, G1c), groups treated with magnesium or calcium from the third week (respectively G2m, G2c). The mice treated by ions performed better than GR mice, but magnesium was more effective. Memory (short term-long term) was differently affected by kainate or improved by magnesium-calcium. In addition, magnesium demonstrated an increasing therapeutic effect over time while calcium had an acute and apparently decreasing action in the G1c group that received calcium early.

Le calcium et le magnésium sont des ions divalents multipotents importants pour le métabolisme, l'excitabilité, et la plasticité de la névroglie. En raison de leurs multiples propriétés, leur carence provoque des processus cérébraux complexes menant à des aberrations aigües voire durables au niveau de l'excitabilité et des réseaux neuronaux. Ces ions sont habituellement prescrits dans des contextes cliniques d'hyperexcitabilité neuronale comme la prééclampsie et le stress chronique. Notre objectif était d'évaluer si le magnésium à 20 mg/kg et le calcium à 100 mg/kg pouvaient améliorer le pronostic mnésique dans le modèle kaïnique d'épilepsie mésiale temporale chez les souris. Les animaux furent organisés en six groupes : groupe témoin (sans kaïnate), groupe de référence sans administration d'ions (GR), groupes traités au magnésium ou au calcium dès le troisième jour (respectivement G1m, G1c), groupes traités au magnésium ou au calcium à partir de la troisième semaine (respectivement G2m, G2c). Les souris traitées ont toutes présenté de meilleures performances que les souris GR, mais le magnésium était plus efficace. La mémoire (court terme­long terme) était touchée différemment par le kaïnate ou améliorée par le magnésium et le calcium. De plus, le magnésium a démontré un effet thérapeutique croissant avec le temps alors que le calcium avait un effet aigu qui semblait se dégrader pour le groupe G1c qui reçut précocement du calcium.

Computer-assisted analysis of routine EEG to identify hidden biomarkers of epilepsy: A systematic review.

Background: Computational analysis of routine electroencephalogram (rEEG) could improve the accuracy of epilepsy diagnosis. We aim to systematically assess the diagnostic performances of computed biomarkers for epilepsy in individuals undergoing rEEG. Methods: We searched MEDLINE, EMBASE, EBM reviews, IEEE Explore and the grey literature for studies published between January 1961 and December 2022. We included studies reporting a computational method to diagnose epilepsy based on rEEG without relying on the identification of interictal epileptiform discharges or seizures. Diagnosis of epilepsy as per a treating physician was the reference standard. We assessed the risk of bias using an adapted QUADAS-2 tool. Results: We screened 10 166 studies, and 37 were included. The sample size ranged from 8 to 192 (mean=54). The computed biomarkers were based on linear (43%), non-linear (27%), connectivity (38%), and convolutional neural networks (10%) models. The risk of bias was high or unclear in all studies, more commonly from spectrum effect and data leakage. Diagnostic accuracy ranged between 64% and 100%. We observed high methodological heterogeneity, preventing pooling of accuracy measures. Conclusion: The current literature provides insufficient evidence to reliably assess the diagnostic yield of computational analysis of rEEG. Significance: We provide guidelines regarding patient selection, reference standard, algorithms, and performance validation.

Epilepsy and cerebral developmental venous anomalies (DVAs): A systematic review.

OBJECTIVE: Cerebral developmental venous anomalies (DVAs) are frequent and rarely symptomatic. When symptomatic, DVAs may present with seizures; however, little is known about the characteristics of DVA-related epilepsy. In this systematic review, we aim to describe the clinical and paraclinical features of patients with DVA-related epilepsy. METHODS: This review was registered on PROSPERO (CRD42021218711). We searched the MEDLINE/PubMed and Scopus databases for case reports/series on patients with DVAs complicated by seizures. Studies describing patients with a potentially epileptogenic comorbid lesion close to their seizure focus were excluded. Descriptive statistical analyses were performed to synthetize patient characteristics. The methodological quality of each study was evaluated using a standardized appraisal tool. RESULTS: In total, 66 patients were included from 39 articles. The frontal lobe was the most common location for DVAs. The superior sagittal sinus drained half of the DVAs. Seizures were inaugural in most cases, and the most common manifestations accompanying seizures were headaches. EEG was abnormal in 93% of cases, but only 26% had characteristic epileptic spikes. More than half the patients suffered a medical complication due to their DVA, with hemorrhage and thrombosis being the most common. Refractory seizures were encountered in 19% of individuals. At 12 months of follow-up, 75% of patients were seizure free. Most included studies were at low risk of bias. SIGNIFICANCE: Epilepsy can be a complication of DVAs; these DVAs are mostly frontal or parietal, draining via the superior sagittal sinus or the vein of Galen.

Sudden unexpected death in epilepsy (SUDEP): A bibliometric analysis.

OBJECTIVE: The literature on sudden unexpected death in epilepsy (SUDEP) has been evolving at a staggering rate. We conducted a bibliometric analysis of the SUDEP literature with the aim of presenting its structure, performance, and trends. METHODS: The Scopus database was searched in April 2023 for documents explicitly detailing SUDEP in their title, abstract, or keywords. After the removal of duplicate documents, bibliometric analysis was performed using the R package bibliometrix and the program VOSviewer. Performance metrics were computed to describe the literature's annual productivity, most relevant authors and countries, and most important publications. Science mapping was performed to visualize the relationships between research constituents by constructing a country collaboration network, co-authorship network, keyword co-occurrence network, and document co-citation network. RESULTS: A total of 2140 documents were analyzed. These documents were published from 1989 onward, with an average number of citations per document of 25.78. Annual productivity had been on the rise since 2006. Out of 6502 authors, five authors were in both the list of the ten most productive and the list of the ten most cited authors: Devinsky O, Sander JW, Tomson T, Ryvlin P, and Lhatoo SD. The USA and the United Kingdom were the most productive and cited countries. Collaborations between American authors and European authors were particularly rich. Prominent themes in the literature included those related to pathophysiology (e.g., cardiac arrhythmia, apnea, autonomic dysfunction), epilepsy characteristics (e.g., epilepsy type, refractoriness, antiseizure medications), and epidemiology (e.g., incidence, age, sex). Emerging themes included sleep, genetics, epilepsy refractoriness, and non-human studies. SIGNIFICANCE: The body of literature on SUDEP is rich, fast-growing, and benefiting from frequent international collaborations. Some research themes such as sleep, genetics, and animal studies have become more prevalent over recent years.

Unexpected cardiorespiratory findings postictally and at rest weeks prior to SUDEP.

Introduction: Mechanisms underlying sudden unexpected death in epilepsy (SUDEP) are unclear, but autonomic disorders are thought to play a critical role. However, those dysfunctions have mainly been reported in the peri-ictal context of generalized tonic-clonic seizures. Here, we explored whether heart rate variability (HRV), heart rate (HR), and breathing rate (BR) changes could be observed perictally during focal seizures with or without impaired awareness as well as interictally to assess the risk of SUDEP. We report the case of a 33-year-old patient with drug-resistant bilateral temporal lobe epilepsy who died at home probably from an unwitnessed nocturnal seizure ("probable SUDEP"). Methods: Ictal and interictal HRV as well as postictal cardiorespiratory analyses were conducted to assess autonomic functions and overall SUDEP risk. The SUDEP patient was compared to two living male patients from our local database matched for age, sex, and location of the epileptic focus. Results: Interictal HRV analysis showed that all sleep HRV parameters and most awake HRV parameters of the SUDEP patient were significantly lower than those of our two control subjects with bitemporal lobe epilepsy without SUDEP (p < 0.01). In two focal with impaired awareness seizures (FIAS) of the SUDEP patient, increased postictal mean HR and reduced preictal mean high frequency signals (HF), known markers of increased seizure severity in convulsive seizures, were seen postictally. Furthermore, important autonomic instability and hypersensitivity were seen through fluctuations in LF/HF ratio following two seizures of the SUDEP patient, with a rapid transition between sympathetic and parasympathetic activity. In addition, a combination of severe hypopnea (202 s) and bradycardia (10 s), illustrating autonomic dysfunction, was found after one of the SUDEP patient's FIAS. Discussion: The unusual cardiorespiratory and HRV patterns found in this case indicated autonomic abnormalities that were possibly predictive of an increased risk of SUDEP. It will be interesting to perform similar analyses in other SUDEP cases to see whether our findings are anecdotal or instead suggestive of reliable biomarkers of high SUDEP risk in focal epilepsy, in particular focal with or without impaired awareness seizures.

Use of non-medical cannabis in epilepsy: A scoping review.

Objective: The use of medical cannabis among people with epilepsy (PWE) has been garnering increasing interest. In this scoping review, we aimed to summarize the literature on recreational/non-medical cannabis (NMC) use in PWE, focusing on the experience, habits, and beliefs of PWE regarding NMC. Methods: Four databases (OVID Medline, OVID Embase, Ovid APA PsycInfo, and Web of Science) were searched for studies describing NMC use in PWE. NMC was defined as cannabis products procured from sources other than by prescription. Studies that consisted in original research and that detailed the experience, habits, and/or beliefs of PWE regarding NMC use were included in the analysis. Data pertaining to study identification, demographics, NMC use, and epilepsy characteristics were extracted. Descriptive statistical analyses and reflexive thematic analyses were performed to map these data. Results: In total, 3,228 records were screened, and 66 were included for analysis: 45 had mainly adult samples, whereas 21 had mainly pediatric samples. Most studies were published after 2010, originated from the USA, and were cross-sectional. The median number of PWE using cannabis in these studies was 24.5 (1-37,945). No studies showcased elderly PWE, and most had predominantly Caucasian samples. The lifetime prevalence of NMC use in PWE was variable, ranging between 0.69 and 76.8%. Factors frequently associated with NMC use in PWE were male sex, younger adult age, and lower education status. Children with epilepsy took NMC primarily for seizure control, using high CBD/THC ratios, and only orally. Adults with epilepsy took NMC for various reasons including recreationally, using variable CBD/THC ratios, and predominantly through smoking. The majority of PWE across all studies perceived that NMC aided in seizure control. Other aspects pertaining to NMC use in PWE were rarely reported and often conflicting. Conclusion: The literature on NMC use in PWE is sparse and heterogeneous, with many salient knowledge gaps. Further research is necessary to better understanding the experience, habits, and beliefs of PWE pertaining to NMC.

Computer-assisted analysis of routine electroencephalogram to identify hidden biomarkers of epilepsy: protocol for a systematic review.

INTRODUCTION: The diagnosis of epilepsy frequently relies on the visual interpretation of the electroencephalogram (EEG) by a neurologist. The hallmark of epilepsy on EEG is the interictal epileptiform discharge (IED). This marker lacks sensitivity: it is only captured in a small percentage of 30 min routine EEGs in patients with epilepsy. In the past three decades, there has been growing interest in the use of computational methods to analyse the EEG without relying on the detection of IEDs, but none have made it to the clinical practice. We aim to review the diagnostic accuracy of quantitative methods applied to ambulatory EEG analysis to guide the diagnosis and management of epilepsy. METHODS AND ANALYSIS: The protocol complies with the recommendations for systematic reviews of diagnostic test accuracy by Cochrane. We will search MEDLINE, EMBASE, EBM reviews, IEEE Explore along with grey literature for articles, conference papers and conference abstracts published after 1961. We will include observational studies that present a computational method to analyse the EEG for the diagnosis of epilepsy in adults or children without relying on the identification of IEDs or seizures. The reference standard is the diagnosis of epilepsy by a physician. We will report the estimated pooled sensitivity and specificity, and receiver operating characteristic area under the curve (ROC AUC) for each marker. If possible, we will perform a meta-analysis of the sensitivity and specificity and ROC AUC for each individual marker. We will assess the risk of bias using an adapted QUADAS-2 tool. We will also describe the algorithms used for signal processing, feature extraction and predictive modelling, and comment on the reproducibility of the different studies. ETHICS AND DISSEMINATION: Ethical approval was not required. Findings will be disseminated through peer-reviewed publication and presented at conferences related to this field. PROSPERO REGISTRATION NUMBER: CRD42022292261.

Cross-bispectrum connectivity of intracranial EEG: A novel approach to seizure onset zone localization.

Connectivity analyses of intracranial electroencephalography (iEEG) could guide surgical planning for epilepsy surgery by improving the delineation of the seizure onset zone. Traditional approaches fail to quantify important interactions between frequency components. To assess if effective connectivity based on cross-bispectrum -a measure of nonlinear multivariate cross-frequency coupling- can quantitatively identify generators of seizure activity, cross-bispectrum connectivity between channels was computed from iEEG recordings of 5 patients (34 seizures) with good postsurgical outcome. Personalized thresholds of 50% and 80% of the maximum coupling values were used to identify generating electrode channels. In all patients, outflow coupling between α (8-15 Hz) and ß (16-31 Hz) frequencies identified at least one electrode inside the resected seizure onset zone. With the 50% and 80% thresholds respectively, an average of 5 (44.7%; specificity = 82.6%) and 2 (22.5%; specificity = 99.0%) resected electrodes were correctly identified. Results show promise for the automatic identification of the seizure onset zone based on cross-bispectrum connectivity analysis.

Machine-learning for the prediction of one-year seizure recurrence based on routine electroencephalography.

Predicting seizure recurrence risk is critical to the diagnosis and management of epilepsy. Routine electroencephalography (EEG) is a cornerstone of the estimation of seizure recurrence risk. However, EEG interpretation relies on the visual identification of interictal epileptiform discharges (IEDs) by neurologists, with limited sensitivity. Automated processing of EEG could increase its diagnostic yield and accessibility. The main objective was to develop a prediction model based on automated EEG processing to predict one-year seizure recurrence in patients undergoing routine EEG. We retrospectively selected a consecutive cohort of 517 patients undergoing routine EEG at our institution (training set) and a separate, temporally shifted cohort of 261 patients (testing set). We developed an automated processing pipeline to extract linear and non-linear features from the EEGs. We trained machine learning algorithms on multichannel EEG segments to predict one-year seizure recurrence. We evaluated the impact of IEDs and clinical confounders on performances and validated the performances on the testing set. The receiver operating characteristic area-under-the-curve for seizure recurrence after EEG in the testing set was 0.63 (95% CI 0.55-0.71). Predictions were still significantly above chance in EEGs with no IEDs. Our findings suggest that there are changes other than IEDs in the EEG signal embodying seizure propensity.

Prevalence of Bipolar Symptoms or Disorder in Epilepsy: A Systematic Review and Meta-analysis.

BACKGROUND AND OBJECTIVES: This systematic review with meta-analysis (PROSPERO: CRD42021249336) was performed to estimate the pooled lifetime prevalence of bipolar symptoms (BS) and bipolar disorder (BD) in people with epilepsy (PWE). METHODS: A search was performed on June 5, 2021, in 4 databases (MEDLINE/PubMed, Ovid EMBASE, Ovid APA PsycInfo, and Web of Science) for original research reporting on BS/BD in PWE, with no restriction on language or time of publication. Inclusion criteria were as follows: (1) original research, (2) cross-sectional study design component, (3) reported lifetime prevalence of BS/BD or enough information to calculate an estimate, and (4) reported the method by which participants were deemed bipolar. Studies based on an exclusively pediatric population were excluded. To calculate pooled lifetime prevalence of BS/BD, 2 meta-analytic random-effects models were fitted, one for BS and the other for BD. Risk of bias was assessed using a standardized appraisal tool for studies reporting prevalence. Certainty of evidence was evaluated using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. RESULTS: A total of 750 records were screened and 17 studies were included for analysis: 7 provided prevalence estimates for only BS, 8 for only BD, and 2 for both BS and BD. After outlier exclusion and subgroup analysis using screening method as a moderator, the pooled prevalence of BS in PWE was 12.3% (95% CI 10.6%-14.1%) (7,506 PWE). The pooled prevalence of BD in PWE was 4.5% (95% CI 2.2%-7.4%) (48,334 PWE). Considerable heterogeneity was present, more so for BD than for BS, and could be explained through differences in population demographics and study methodology. DISCUSSION: This study's main limitation was regarding the certainty of evidence. However, our estimates of prevalence should prompt further research on BS/BD in PWE. Given the significant morbidity associated with BD, clinicians should carefully screen PWE for BS.

Multispectral intraoperative imaging for the detection of the hemodynamic response to interictal epileptiform discharges.

Interictal epileptiform discharges (IEDs) are brief neuronal discharges occurring between seizures in patients with epilepsy. The characterization of the hemodynamic response function (HRF) specific to IEDs could increase the accuracy of other functional imaging techniques to localize epileptiform activity, including functional near-infrared spectroscopy and functional magnetic resonance imaging. This study evaluated the possibility of using an intraoperative multispectral imaging system combined with electrocorticography (ECoG) to measure the average HRF associated with IEDs in eight patients. Inter-patient variability of the HRF is illustrated in terms of oxygenated hemoglobin peak latency, oxygenated hemoglobin increase/decrease following IEDs, and signal-to-noise ratio. A sub-region was identified using an unsupervised clustering algorithm in three patients that corresponded to the most active area identified by ECoG.

Déjà-vu evoked by electrical stimulation of the insula.

OBJECTIVE: Déjà-vu is a mental phenomenon commonly experienced during temporal lobe seizures and can be evoked by electrical stimulation of the temporal lobe. We analyzed reproducible déjà-vu experiences evoked by stimulating the insula in two patients with pharmacoresistant temporal lobe epilepsy. METHODS: We reviewed video-electroencephalography (EEG) recordings from extraoperative electrical cortical stimulation sessions. In addition, we performed the directed transfer function (DTF) effective connectivity measure of monopolar signals in Patient 1. To highlight elective changes due to each stimulation, we subtracted pre-stimulation DTF matrices from early poststimulation matrices. This analysis was performed for both non-inducing-déjàvu stimulation (control matrix) and déjà-vu-inducing stimulation (active matrix). Finally, the control matrix was subtracted from the active matrix. RESULTS: Comparison of effective connectivity during control stimulation versus déjà-vu-inducing stimulation revealed a reversal of connectivity levels in three main regions: the contralateral inferior insula (the ipsilateral insula could not be analyzed), bilateral mesiotemporal regions and the ipsilateral superior frontal gyrus. The drivers of evoked déjà-vu were the mesiotemporal regions (mainly ipsilateral) and the ipsilateral superior frontal gyrus. SIGNIFICANCE: Although our findings are possibly anecdotal, the insula may (in rare instances) remotely generate unexpected déjà-vu. If confirmed by further studies, this might change the assessment strategy for possible causes of anterior temporal lobectomy failure.