Approaches to refractory epilepsy

Dietary interventions targeting the neurolipidome in epilepsy: From preclinical models to clinical applications and future therapeutic approaches

Epilepsy is a neurological disorder affecting approximately 50 million people globally and is characterised by recurrent, unprovoked seizures resulting from abnormal, excessive synchronised firing of neurons. Developing new therapeutic targets and biomarkers is key to improving the diagnosis, treatment, and management. This scoping review examines the current literature on the preclinical and clinical applications of dietary interventions that target the neurolipidome in epilepsy. Specifically, it investigates the role of lipids in the underlying pathogenesis of epilepsy. A comprehensive search of databases was conducted to identify peer-reviewed articles published in the past ten years. Original research articles focusing on both adult and paediatric epilepsy and disrupted lipid metabolism were included, resulting in a total of 101 papers. Our review identified several key lipids implicated in the pathogenesis of epilepsy, including sphingolipids, free fatty acids, endocannabinoids, cholesterol, triglycerides, and phospholipids, and also explores the complex interactions between these lipids and their roles in the disease process. Furthermore, our study highlighted that the Ketogenic Diet (KD) and Modified Atkins Diet (MAD) have proven effective adjunctive or alternative treatments in paediatric and adult populations, improving patient quality of life and reducing seizure frequency. Additionally, treatment with lipid-based supplements, such as eicosapentaenoic acid, docosahexaenoic acid, fish oil, and cannabidiol, has been associated with a reduction in seizure rates in patients with drug-resistant epilepsy. In summary, findings from this study indicate that KD and MAD lipid-based supplements are effective for managing epilepsy in paediatrics, adults, and animal models. However, further research is necessary to elucidate the pathophysiological mechanisms underlying the role of lipids in the development and progression of epilepsy.

Evaluating the effectiveness of medical therapy in infantile epileptic spasms syndrome due to surgically-remediable lesions

OBJECTIVE

This single-center retrospective study examined the response to initial standard therapy in children with infantile epileptic spasms syndrome (IESS) associated with surgically-remediable lesion and evaluated the risk factors for drug resistance. We assessed whether the failure of the first standard therapy for surgically-remediable IESS predicted eventual drug resistance.

METHODS

New-onset IESS with surgically-remediable lesions was included. Regression analysis was performed to identify risk factors for drug resistance. Kaplan-Meier survival analysis stratified by the response to first standard therapy was conducted to explore if earlier recognition of drug-resistant epilepsy (DRE) was possible.

RESULTS

We identified 61 patients (57% female) with IESS and surgically-remediable lesion (median follow-up of 52 months). First standard treatment started at a median of 15 days after IESS onset resulted in favorable initial response in 31%. Response rate to second standard therapy among those who failed first treatment was 53%, with an overall response rate to sequential standard therapy of 63.8%. Relapses (epileptic spasms/focal seizures) were frequent (59%). At last follow-up, 41% (n = 25) remained drug responsive. The cumulative proportion of survival free of drug resistance was 57% at 2 months, dropping to 38% at 36 months after IESS diagnosis. The odds for DRE increased with extensive magnetic resonance imaging (MRI) abnormality (odds ratio [OR] = 38.5) and congenital-structural abnormality (OR = 23.3) and decreased with older age at IESS onset (OR = 0.68). Kaplan-Meier survival curve differed significantly between responders and non-responders to first standard therapy (p = .02). In the drug-resistant group (n = 36), 34 underwent surgery with Engel class I outcome in 76.5%.

SIGNIFICANCE

Although two-thirds of surgically-remediable IESS exhibited an initial response to medical therapy, relapses were frequent. The majority progressed to DRE during follow-up, particularly those with younger age at IESS onset, congenital-structural etiology, or extensive MRI abnormalities. Patients at risk for DRE can be recognized early by the lack of response to first standard therapy (OR 4.15). Our findings can help reduce delays for surgical referral in patients with surgically-remediable IESS.

Improvement of FDG PET/CT and MRI concordance in temporal lobe epilepsy pre-surgical assessment using statistical parametric mapping Z-scores

AIM

This retrospective study evaluates the diagnostic performance of statistical parametric mapping (SPM) analysis of interictal F18-fluoro-deoxy-D-glucose positron emission tomography computed tomography (FDG PET/CT) in temporal lobe epilepsy (TLE) patients, aiming to enhance image reporting consistency and correlation between magnetic resonance imaging (MRI) and FDG PET/CT findings and boost confidence in the surgical decision-making.

MATERIALS AND METHODS

Forty-nine TLE patients undergoing MRI and FDG PET/CT imaging at a tertiary epilepsy service were included. Images were visually interpreted by an experienced radiologist and nuclear medicine physician. SPM-based quantitative analysis for FDG PET/CT including Z score asymmetric index (ZAI) was performed. Statistical analyses include receiver operating characteristic curve and Cohen's k statistics.

RESULTS

Significant differences in the standardised uptake value (SUV) ratio and ZAI were observed among left TLE, nonepilepsy, and right TLE (p < 0.01). The areas under the curves for left/nonleft and right/nonright groups were 0.838 and 0.780, respectively. The cutoff value to separate left TLE from nonepilepsy and right TLE was 0.305 with 89.7% sensitivity, 80.0% specificity, 94.6% positive predictive value (PPV), 66.7% negative predictive value (NPV), and a 0.697 Youden index for diagnosis. It was 0.190 to separate right TLE from the other 2 with 87.5% sensitivity, 75.6% specificity, 41.2% PPV, 96.9% NPV, and a 0.631 Youden index for diagnosis. The intermethod agreement between MRI and SUV ratio was moderate (k = 0.48; 95% CI, 0.32-0.65) and that between FDG PET/CT qualitative assessment and ZAI was moderate (k = 0.43; 95% CI, 0.10-0.76).

CONCLUSION

FDG PET/CT-based SUV ratios and ZAI show promising diagnostic value in TLE patients, facilitating the integration of FDG PET/CT practice into presurgical assessment for medically refractory epilepsy.

A Dilemma: Electrographic Seizure Activity in the Absence of Clinically Perceptible Seizures and the Ethical Challenges of Medical Decision-Making

A 37-year-old male with refractory left temporal epilepsy was admitted to the epilepsy monitoring unit to examine correlates of observable clinical seizure activity, those captured by responsive neurostimulation system (RNS) and continuous video electroencephalogram (cvEEG). The patient was diagnosed at age three, was on three anti-epileptic drugs, with an RNS implant since 2020 and was admitted to the epilepsy monitoring unit. The patient reported no seizures since 2019. cvEEG and RNS data were collected, and a comprehensive neuropsychological evaluation was conducted. cvEEG revealed brief electrographic activity originating from the left and right anterior temporal regions, occurring mainly on the left side. The activity was characterized ictally by prominent anterior temporal sharp waves, with a left-sided predominance. RNS data showed similar results but recorded electrographic activity in excess of cvEEG. Although clinical and electrographic manifestations tend to be stereotyped for seizures, there were no behavioral observations of clinical seizures during these recorded electrographic seizures on RNS data. The patient also reported no seizures. Neuropsychological results showed impairment across multiple cognitive domains. This case report highlights the need for a more detailed approach to determining allowable electrographic activity since these thresholds directly impact restrictions on patients with epilepsy. Highly sensitive measurement tools may better detect seizures, but in isolation, they cannot fully convey a complete picture of the patient's status without other data and clinical indicators. Data from emerging technology must be weighed in conjunction with clinical symptoms to optimize patient safety, quality of life, and outcomes.

Nuclear Medicine Imaging in Epilepsy

Approximately one-third of patients with focal epilepsy have medically refractory focal epilepsy (MRFE), which significantly impacts their quality of life. Once a seizure focus is identified and determined to be in the noneloquent cortex, it can be surgically resected with the goal of freedom from seizures and minimal neurocognitive deficit. During noninvasive (phase I) presurgical planning, functional (nuclear) imaging and structural imaging are complementary in the accurate localization of the epileptogenic zone (EZ). PET and SPECT are complementary functional imaging modalities. Fluorine 18-fluorodeoxyglucose PET shows hypometabolism in the EZ, while SPECT radiotracers are used to assess regional cerebral perfusion. Functional imaging plays a more important role in patients with nonlesional epilepsy (approximately one-third of patients with MRFE), in patients with multiple lesions, or in the setting of electrophysiologic-structural discordance. Nuclear medicine imaging also helps in evaluating the functional integrity of the rest of the brain and unmasking abnormalities that are not apparent at structural imaging before surgery. During invasive (phase II) evaluation, the EZ seen at functional imaging helps in guiding intracranial electrode placement. This review of nuclear medicine imaging of epilepsy is focused on the radiotracers used, imaging acquisition and postprocessing, commonly encountered causes of MRFE in adults and children, radiologic appearances of MRFE, imaging artifacts, and interpretation pitfalls. The goal is to guide radiologists in optimally performing and interpreting these studies for effective multidisciplinary discussions of these complex patient cases. ©RSNA, 2025 Supplemental material is available for this article.

Anti-Epileptic Activity of Mitocurcumin in a Zebrafish-Pentylenetetrazole (PTZ) Epilepsy Model

Background/Objectives: Ongoing challenges in epilepsy therapy warrant research on alternative treatments that offer improved efficacy and reduced side effects. Designed to enhance mitochondrial targeting and increase bioavailability, mitocurcumin (MitoCur) was evaluated for the first time as an antiepileptic agent, with curcumin (Cur) and sodium valproate (VPA), a standard antiepileptic drug, included for comparison. This study investigated the effects on seizure onset, severity, and progression in a zebrafish model of pentylenetetrazole (PTZ)-induced seizures and measured the concentrations of the compounds in brain tissue. Methods: Zebrafish were pre-treated with MitoCur and Cur (both at 0.25 and 0.5 µM doses) and VPA (0.25 and 0.5 mM) and observed for four minutes to establish baseline locomotor behavior. Subsequently, the animals were exposed to a 5 mM PTZ solution for 10 min, during which seizure progression was observed and scored as follows: 1-increased swimming; 2-burst swimming, left and right movements; 3-circular movements; 4-clonic seizure-like behavior; 5-loss of body posture. The studied compounds were quantified in brain tissue through HPLC and LC-MS. Results: Compared to the control group, all treatments reduced the distance moved and the average velocity, without significant differences between compounds or doses. During PTZ exposure, seizure latencies revealed that all treatments effectively delayed seizure onset up to score 4, demonstrating efficacy in managing moderate seizure activity. Notably, MitoCur also provided significant protection against the most severe seizure score (score 5). Brain tissue uptake analysis indicated that MitoCur achieved higher concentrations in the brain compared to Cur, at both doses. Conclusions: These results highlight the potential of MitoCur as a candidate for seizure management.

Vascular imaging for Stereoelectroencephalography: A safety and planning study

BACKGROUND

Stereoelectroencephalography (SEEG) is a procedure used to localize the epileptogenic zone in patients with medically refractory epilepsy, involving the stereotactic implantation of electrodes into brain parenchyma. Magnetic Resonance Imaging (MRI), Digital Subtraction Angiography, and Computed Tomography have been used preoperatively to prevent Intracranial Hemorrhage (ICH) by identifying electrode-vessel conflicts (EVC's) on planned electrode trajectories. There is variation in the use of Digital Subtraction Angiography and non-invasive sequences for vascular planning. Digital Subtraction Angiography provides high spatial resolution, but carries risks of arterial dissection, groin and retroperitoneal hematoma, and a 0.5-1.9% risk of stroke. Our group has incorporated Intravenous Cone Beam Computed Tomography (CBCT A/V) Brain into our SEEG workflow, given its effective implementation in other neurosurgical domains. Primary aims include validating the safety of our CBCT A/V sequence for SEEG planning and determining if CBCT A/V is comparable to other modalities in detecting EVC's. Secondary aims include elucidating the relationship of conflicting vessel calibre with ICH incidence in SEEG using CBCT A/V imaging.

METHODS

A single-center retrospective study was conducted of 20 patients who underwent preoperative CBCT A/V Brain and MRI Brain with gadolinium enhancement, encompassing 273 electrode implantations from August 2020 - July 2023. The incidence and grade of post-implant, post-explant symptomatic ICH and asymptomatic ICH was noted. The total number of EVC's identifiable on MRI and CBCT A/V was recorded, along with average diameter of conflicting vessels.

RESULTS

Across 20 patients and 273 implanted electrodes, there were four ICH events, where two were symptomatic and two were asymptomatic. The mean diameter of EVC's across all patients was 1.4 mm (±0.5). A significant difference (P < 0.0001) was observed between the number of EVC's that CBCT A/V could identify (20) compared to MRI (6). Two EVC's were identified in the region of two symptomatic ICH's, with the mean diameter of these conflicted vessels being 1.5 mm (±0.4). The two symptomatic ICH-associated EVC's were observed on CBCT A/V but not MRI.

CONCLUSIONS

In our series, CBCT A/V demonstrates an acceptable safety profile for SEEG planning compared to other imaging modalities. CBCT A/V identified significantly more EVC's compared to MRI, including those contributing to transient symptomatic intracranial hemorrhage. A conflicting vessel calibre of less than 1.2 mm on CBCT A/V did not contribute to ICH in our SEEG series.

The reality of epilepsy in primary care in Rio de Janeiro: the importance of educational projects for better patient care

BACKGROUND

 The Basic Health Unit (Unidade Básica de Saúde - UBS, in Portuguese) is the first point of contact in the public healthcare system for people with epilepsy. Primary care professionals need to appropriately diagnose, treat, and refer, if necessary, to tertiary services.

OBJECTIVE

 To evaluate the knowledge of UBS professionals on the management of patients with epilepsy in Rio de Janeiro.

METHODS

 Online questionnaires were performed on the topic of epilepsy before and after exposure to classes taught by epileptologists.

RESULTS

 A total of 66 doctors participated, 54.5% of whom were residents or trained in family medicine. The majority had from 1 to 3 years of practice. Insecurity prevailed in the management of pregnant women and the elderly. Around 59.1% of the participants referred patients with seizures without examinations. A total of 78% of the participants did not correctly classify seizure types, and 2/3 did not define drug-resistant epilepsy. Induction and broad-spectrum drugs were common. The therapeutic decision depended on availability in the basic health unit (UBS) (81.8%), dosage (60.6%), side effects (34.8%), and age (36.4%). Comorbidities and sex influenced 1/4 of the sample. For 23% of the participants, the type of crisis did not affect the choice. Regarding typical non-pharmacological options, 75% of the participants were aware of cannabidiol, 40.9% of surgery, 22.7% of ketogenic diet, and 22.8% of deep brain stimulation/vagus nerve stimulation (DBS/VNS). A total of 90.2% indicated the need for training.

CONCLUSION

 There are deficits in the knowledge of UBS professionals in the management of epilepsy. Specialized training is imperative to optimize the care offered within SUS.

Efficacy and safety of adjunctive cenobamate based on patient etiology: Post-hoc analysis of YKP3089C017 randomized clinical trial

INTRODUCTION

Adjunctive cenobamate was effective and safe for the treatment of uncontrolled focal onset seizures in a randomized, double-blind, placebo-controlled, phase 2 study (YKP3089C017; NCT01866111). This post-hoc analysis assessed the efficacy of adjunctive cenobamate in the treatment of patients with different epileptic etiologies during the study.

METHODS

Adult patients with uncontrolled focal seizures who previously received 1 to 3 antiseizure medications (ASMs) were randomly assigned in a ratio of 1:1:1:1 to receive placebo or cenobamate 100, 200 or 400 mg/day. Patients were further stratified based on their etiologic causes as genetic/presumed genetic, unknown cause, structural cause, and not reported (NR) groups. The frequency per 28 days for an 18-week double-blind treatment period, responder rates (≥50 %, ≥75 %, ≥90 %, and 100 %) during the maintenance phase (12 weeks), and safety were assessed.

RESULTS

A total of 394 patients were categorized into the genetic/presumed genetic (n = 9; 2.28 %), unknown cause (n = 199; 50.51 %), structural cause (n = 177; 44.92 %), and NR (n = 13; 3.30 %) groups, with 4 patients were classified into either of the two etiological causes each. The baseline characteristics were comparable. The percentage of reduction in seizure frequency per 28 days was significantly higher in the cenobamate-treated structural (p = 0.01) and unknown cause (p = 0.0003) groups compared with the placebo group. Responder rates of ≥50 %, ≥75 %, ≥90 %, and 100 % were also higher with cenobamate therapy. Notably, no serious treatment-emergent adverse events (TEAEs) were observed in the genetic/presumed genetic group treated with cenobamate. The most common TEAEs (≥10 %) occurring in patients treated with cenobamate were nervous system disorders by system organ class, and somnolence was the most commonly reported TEAE.

CONCLUSION

Cenobamate reduces seizures in adult patients previously treated with ASMs, with high responder rates and acceptable safety, regardless of underlying causes.

Circulatory Metabolite Ratios as Indicators of Lifestyle Risk Factors Based on a Greek NAFLD Case-Control Study

An ensemble of confounding factors, such as an unhealthy diet, obesity, physical inactivity, and smoking, have been linked to a lifestyle that increases one's susceptibility to chronic diseases and early mortality. The circulatory metabolome may provide a rational means of pinpointing the advent of metabolite variations that reflect an adherence to a lifestyle and are associated with the occurrence of chronic diseases. Data related to four major modifiable lifestyle factors, including adherence to the Mediterranean diet (estimated on MedDietScore), body mass index (BMI), smoking, and physical activity level (PAL), were used to create the lifestyle risk score (LS). The LS was further categorized into four groups, where a higher score group indicates a less healthy lifestyle. Drawing on this, we analyzed 223 NMR serum spectra, 89 MASLD patients and 134 controls; these were coupled to chemometrics to identify "key" features and understand the biological processes involved in specific lifestyles. The unsupervised analysis verified that lifestyle was the factor influencing the samples' differentiation, while the supervised analysis highlighted metabolic signatures. Τhe metabolic ratios of alanine/formic acid and leucine/formic acid, with AUROC > 0.8, may constitute discriminant indexes of lifestyle. On these grounds, this research contributed to understanding the impact of lifestyle on the circulatory metabolome and highlighted "prudent lifestyle" biomarkers.

Use of cannabidiol in the treatment of drug-refractory epilepsy in children and young adults: A systematic review

Objectives

Epilepsy poses a significant challenge in pediatric and adolescent populations, impacting not only seizures but also psychological and cognitive comorbidities, leading to higher mortality rates than the general population. Drug-refractory epilepsy, resistant to conventional treatments, affects a range of 7-20% of pediatric patients. The search for alternative therapies has led to exploring the therapeutic potential of Cannabis sativa L. compounds, particularly cannabidiol (CBD). Examine the use of CBD for treating drug-refractory epilepsy in children and young adults, summarizing existing evidence on its efficacy.

Materials and Methods

A systematic review, following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, assessed studies from 2018 to 2023, focusing on CBD's efficacy and safety for treatment-resistant epilepsy in pediatric and juvenile populations. The search spanned seven databases, and the studies underwent rigorous screening and data extraction.

Results

Out of 6351 identified articles, eight were selected for review. The included studies reported positive outcomes, with CBD leading to a reduction in seizure frequency ranging from 50% to complete seizure freedom. Adverse effects were mostly mild and reversible, including drowsiness, diarrhea, and loss of appetite.

Conclusion

The CBD emerges as a promising tool for refractory epilepsy in pediatric patients, showing efficacy in reducing seizure frequency and improving overall quality of life. Despite mild and reversible adverse effects, CBD's benefits outweigh the risks. However, more research on long-term effects is needed to fully understand its implications.

Latest advances in mechanisms of epileptic activity in Alzheimer's disease and dementia with Lewy Bodies

Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) stand as the prevailing sources of neurodegenerative dementia, impacting over 55 million individuals across the globe. Patients with AD and DLB exhibit a higher prevalence of epileptic activity compared to those with other forms of dementia. Seizures can accompany AD and DLB in early stages, and the associated epileptic activity can contribute to cognitive symptoms and exacerbate cognitive decline. Aberrant neuronal activity in AD and DLB may be caused by several mechanisms that are not yet understood. Hyperexcitability could be a biomarker for early detection of AD or DLB before the onset of dementia. In this review, we compare and contrast mechanisms of network hyperexcitability in AD and DLB. We examine the contributions of genetic risk factors, Ca2+ dysregulation, glutamate, AMPA and NMDA receptors, mTOR, pathological amyloid beta, tau and α-synuclein, altered microglial and astrocytic activity, and impaired inhibitory interneuron function. By gaining a deeper understanding of the molecular mechanisms that cause neuronal hyperexcitability, we might uncover therapeutic approaches to effectively ease symptoms and slow down the advancement of AD and DLB.

Visually or auditorily induced seizures involve the activation of nonhippocampal brain areas and hippocampal removal does not alleviate seizures in a mouse model of temporal lobe epilepsy

OBJECTIVE

Several studies have attributed epileptic activities in temporal lobe epilepsy (TLE) to the hippocampus; however, the participation of nonhippocampal neuronal networks in the development of TLE is often neglected. Here, we sought to understand how these nonhippocampal networks are involved in the pathology that is associated with TLE disease.

METHODS

A kainic acid (KA) model of temporal lobe epilepsy was induced by injecting KA into dorsal hippocampus of C57BL/6J mice. Network activation after spontaneous seizure was assessed using c-Fos expression. Protocols to induce seizure using visual or auditory stimulation were developed, and seizure onset zone (SOZ) and frequency of epileptic spikes were evaluated using electrophysiology. The hippocampus was removed to assess seizure recurrence in the absence of hippocampus.

RESULTS

Our results showed that cortical and hippocampal epileptic networks are activated during spontaneous seizures. Perturbation of these networks using visual or auditory stimulation readily precipitates seizures in TLE mice; the frequency of the light-induced or noise-induced seizures depends on the induction modality adopted during the induction period. Localization of SOZ revealed the existence of cortical and hippocampal SOZ in light-induced and noise-induced seizures, and the development of local and remote epileptic spikes in TLE occurs during the early stage of the disease. Importantly, we further discovered that removal of the hippocampi does not stop seizure activities in TLE mice, revealing that seizures in TLE mice can occur independent of the hippocampus.

SIGNIFICANCE

This study has shown that the network pathology that evolves in TLE is not localized to the hippocampus; rather, remote brain areas are also recruited. The occurrence of light-induced or noise-induced seizures and epileptic discharges in epileptic mice is a consequence of the activation of nonhippocampal brain areas. This work therefore demonstrates the fundamental role of nonhippocampal epileptic networks in generating epileptic activities with or without the hippocampus in TLE disease.

The possible anti-seizure properties of Klotho

Recurrent seizures in epilepsy may lead to progressive neuronal damage, which can diminish health-related quality of life. Evaluation and control of pathological processes in the brain is valuable. It seems imperative that new markers and approaches for seizure alleviation be discovered. Klotho (Kl), an antiaging protein, has protective effects in the brain against neurological disorders. It may also have antiseizure effects by improving creatine transfer to the brain, upregulating excitatory amino acid transporters, and inhibiting insulin/insulin-like growth factor-1 (IGF-1), Wingless (Wnt), transforming growth factor-beta (TGF-β), and retinoic-acid-inducible gene-I (RIG-I)/nuclear translocation of nuclear factor-κB (NF-κB) pathways. Stimulation and activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) and apoptosis signal-regulating kinase 1 (ASK1)/p38 mitogen‑activated protein kinase (MAPK) signaling pathways could also be considered other possible antiseizure mechanisms of Kl. In the present review, the roles of Kl in the central nervous system as well as its possible anti-seizure properties are discussed for the first time.

Revision and removal of vagus nerve stimulation systems: twenty-five years' experience

BACKGROUND

Epilepsy, a disease characterized by recurrent seizures, is a common chronic neurologic condition. Antiepileptic drugs (AED) are the mainstay of treatment for epilepsy. Vagus nerve stimulation (VNS) surgery is an adjuvant therapy for the treatment of drug refractory epilepsy (DRE). VNS revision and implant removal surgeries remain common.

METHODS

Using a single neurosurgeon data registry for epilepsy surgery, we retrospectively analyzed a total of 824 VNS surgeries. Patients were referred to two Level IV Comprehensive Epilepsy centers (from 08/1997 to 08/2022) for evaluation. Patients were divided into four groups: new device placement, revision surgery, removal surgery, and battery replacement for end-of-life of the generator. The primary endpoint was to analyze the reasons that led patients to undergo revision and removal surgeries. The time period from the index surgery to the removal surgery was also calculated.

RESULTS

The median age of patients undergoing any type of surgery was 34 years. The primary reason for revision surgeries was device malfunction, followed by patients' cosmetic dissatisfaction. There was no statistical sex-difference in revision surgeries. The median age and body mass index (BMI) of patients who underwent revision surgery were 38 years and 26, respectively. On the other hand, the primary reason for removal was lack of efficacy, followed again by cosmetic dissatisfaction. The survival analysis showed that 43% of VNS device remained in place for 5 years and 50% of the VNS devices were kept for 1533 days or 4.2 years.

CONCLUSIONS

VNS therapy is safe and well-tolerated. VNS revision and removal surgeries occur in less than 5% of cases. More importantly, attention to detail and good surgical technique at the time of the index surgery can increase patient satisfaction, minimize the need for further surgeries, and improve acceptance of the VNS technology.

Differentiation of Epileptic Brain Abnormalities among Neurological Patients at Taif Region Using MRI

This study was conducted to assess the prevalence of epilepsy among different age groups and gender of neurological patients in the Taif region and define the most common brain lesion, affecting epileptic patients living in the Taif city using MRI. Data from 150 patients who were clinically diagnosed with epilepsy and had brain MRIs were analyzed using SPSS. Statistical significance was considered when the p value is 0.05. The percentage of epilepsy was generally higher in males than in females in the Taif city, and seizures were different between the studied age groups. However, epilepsy was more pronounced in females than in males at certain age groups. Moreover, white matter lesions were most commonly found in the studied group (27.7%), followed by focal lesions, edema, and stroke with equal percentages (16.9%) and less commonly with congenital diseases (12%) and atrophic changes (9.6%). Epilepsy was more pronounced in females than in males at certain age groups. White matter lesions were identified as the most common lesion, presenting in epilepsy patients in the Taif city.

Unilateral optogenetic kindling of hippocampus leads to more severe impairments of the inhibitory signaling in the contralateral hippocampus

The kindling model has been used extensively by researchers to study the neurobiology of temporal lobe epilepsy (TLE) due to its capacity to induce intensification of seizures by the progressive recruitment of additional neuronal clusters into epileptogenic networks. We applied repetitive focal optogenetic activation of putative excitatory neurons in the dorsal CA1 area of the hippocampus of mice to investigate the role of inhibitory signaling during this process. This experimental protocol resulted in a kindling phenotype that was maintained for 2 weeks after the animals were fully kindled. As a result of the different phases of optogenetic kindling (OpK), key inhibitory signaling elements, such as KCC2 and NKCC1, exhibited distinct temporal and spatial dynamics of regulation. These alterations in protein expression were related to the distinct pattern of ictal activity propagation through the different hippocampal sublayers. Our results suggest the KCC2 disruption in the contralateral hippocampus of fully kindled animals progressively facilitated the creation of pathological pathways for seizure propagation through the hippocampal network. Upon completion of kindling, we observed animals that were restimulated after a rest period of 14-day showed, besides a persistent KCC2 downregulation, an NKCC1 upregulation in the bilateral dentate gyrus and hippocampus-wide loss of parvalbumin-positive interneurons. These alterations observed in the chronic phase of OpK suggest that the hippocampus of rekindled animals continued to undergo self-modifications during the rest period. The changes resulting from this period suggest the possibility of the development of a mirror focus on the hippocampus contralateral to the site of optical stimulations. Our results offer perspectives for preventing the recruitment and conversion of healthy neuronal networks into epileptogenic ones among patients with epilepsy.

Predictive factors for successful vagus nerve stimulation in patients with refractory epilepsy: real-life insights from a multicenter study

Introduction

Vagus nerve stimulation (VNS) therapy is an established treatment for patients with drug-resistant epilepsy that reduces seizure frequency by at least 50% in approximately half of patients; however, the characteristics of the patients with the best response have not yet been identified. Thus, it is important to identify the profile of patients who would have the best response to guide early indications and better patient selection.

Methods

This retrospective study evaluated vagus nerve stimulation (VNS) as an adjuvant therapy for patients with drug-resistant epilepsy from six epilepsy centers in Brazil. Data from 192 patients aged 2-66 years were analyzed, and all patients received at least 6 months of therapy to be included.

Results

Included patients were aged 2-66 years (25.6 ± 14.3), 105 (54.7%) males and 87 (45.8%) females. Median follow-up interval was 5 years (range, 2005-2018). Overall, the response rate (≥50% seizure reduction) after VNS implantation was 65.6% (126/192 patients). Most patients had 50-90% seizure reduction (60.9%) and nine patients became seizure-free. There were no serious complications associated with VNS implantation. The rate of a ≥ 50% seizure reduction response was significantly higher in patients with no history of neurosurgery. The presence of focal without generalized seizures and focal discharges on interictal EEG was associated with better response. Overall, etiological predictors of a better VNS response profile were tumors while a worse response to VNS was related to the presence of vascular malformations and Lennox-Gastaut Syndrome.

Discussion

We observed an association between a better response to VNS therapy no history of neurosurgery, focal interictal epileptiform activity, and focal seizure pattern. Additionally, it is important to highlight that age was not a determinant factor of the response, as children and adults had similar response rates. Thus, VNS therapy should be considered in both adults and children with DRE.

Resective epilepsy surgery in a limited-resource settings: A cohort from a multi-disciplinary epilepsy team in a developing country

BACKGROUND

Multidisciplinary pre-surgical evaluation is vital for epilepsy surgery decision and outcomes. Resective epilepsy surgery with assisted monitoring is currently a standard treatment for focal drug resistant epilepsy (DRE). In resource-limited countries, lack of epilepsy surgery center is a huge challenge. We presented and illustrated how to create a multidisciplinary protocol with resource-limited settings in a developing country and epilepsy surgery outcome using brain mapping and monitoring techniques for ensuring satisfactory resection.

METHODS

We created multicentric incomplete but complementary units covering all epilepsy-related sub-specialties and covering a wide geographical area in our country. Then, we conducted a prospective and multicentric study with low resource settings on patients with focal DRE, who underwent resective epilepsy surgery and were followed up for at least 12 months and were evaluated for postoperative seizure outcome and complications if present. Preoperative comprehensive clinical, neurophysiological, neuropsychological, and radiological evaluations were performed by multidisciplinary epilepsy team. Intraoperative brain mapping including awake craniotomy and direct stimulation techniques, neurophysiological monitoring, and electrocorticography was carried out during surgical resection.

RESULTS

The study included 47 patients (18 females and 29 males) with mean age 20.4 ± 10.02 years. Twenty-two (46.8%) patients were temporal epilepsy while 25 (53.2%) were extra-temporal epilepsy. The epilepsy surgery outcome at the last follow up was Engel Class I (seizure free) in 35 (74.5%), Class II (almost seizure free) in 8 (17%), Class III (worthwhile improvement) in 3 (6.4%), and Class IV (no worthwhile improvement) in 1 patient (2.1%).

CONCLUSION

With low resource settings and lack of single fully equipped epilepsy center, favorable outcomes after resective surgery in patients with focal DRE could be achieved using careful presurgical multidisciplinary selection, especially with using intraoperative brain mapping and electrocorticography techniques.

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 β (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.

Challenges in epilepsy diagnosis and management in a low-resource setting: An experience from Bhutan

Epilepsy is an important cause of morbidity and mortality especially in low- and middle-income countries. People with epilepsy (PWE) face difficulties in access to healthcare, appropriate diagnostic tests and anti-seizure medications (ASM). Bhutan is one such country in the Himalayas that has reported doubling of the prevalence of epilepsy from 155.7 per 100,000 population in 2017 to 312.4 in 2021. The country has one centre for electroencephalography and magnetic resonance imaging for a population of 0.7 million and does not have any neurologists as of 2023. There are 16 ASMs registered in the country but only selected medications are available at the primary level hospitals (phenobarbital, phenytoin and diazepam). There are challenges in the availability of these medicines all time round the year in all levels of hospitals. Neurosurgical treatment options are limited by the lack of adequate pre-surgical evaluation facilities and lack of trained human resources. The majority of PWE have reported facing societal stigma with significant impact on the overall quality of life. It is important to screen for psychiatric comorbidities and provide psychological support wherever possible. There is a need for a comprehensive national guideline that will cater to the needs of PWE and their caregivers within the resources available in the country. A special focus on the institutional and human resource capacity development for the study and care of epilepsy is recommended.

Long-term ANT-DBS effects in pilocarpine-induced epileptic rats: A combined 9.4T MRI and histological study

Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) appears to be effective against seizures in animals and humans however, its therapeutic mechanisms remain elusive. This study aimed to combine 9.4T multimodal magnetic resonance imaging (MRI) with histology to investigate the longitudinal effects of long-term ANT-DBS in pilocarpine-induced epileptic rats. Status epilepsy (SE) was induced by LiCl-pilocarpine injection in 11 adult male Sprague-Dawley rats. Four weeks after SE, chronic epileptic rats underwent either ANT-DBS (n = 6) or sham-DBS (n = 5) surgery. Electroencephalography (EEG) and spontaneous recurrent seizures (SRS) were recorded for 1 week. The T2-weighted image and images from resting-state functional MRI (rs-fMRI) were acquired at three states: before SE, at 4 weeks post-SE, and at 5 weeks post-DBS. Volumes of the hippocampal subregions and hippocampal-related functional connectivity (FC) were compared longitudinally. Finally, antibodies against neuronal nuclei (NeuN) and glial fibrillary acidic proteins were used to evaluate neuronal loss and astrogliosis in the hippocampus. Long-term ANT-DBS significantly reduced seizure generalization in pilocarpine-induced epileptic rats. By analyzing the gray matter volume using T2-weighted images, long-term ANT-DBS displayed morphometric restoration of the hippocampal subregions. Neuronal protection of the hippocampal subregions and inhibition of astrogliosis in the hippocampal subregions were observed in the ANT-DBS group. ANT-DBS caused reversible regulation of FC in the insula-hippocampus and subthalamic nucleus-hippocampus. Long-term ANT-DBS provides comprehensive protection of hippocampal histology, hippocampal morphometrics, and hippocampal-related functional networks.

Cannabis use patterns in drug-resistant and pharmacoresponsive epilepsy: Single tertiary referral center survey investigation

This study sought to identify differences in cannabis use and perceptions about cannabis in mitigating seizure-related symptoms in patients with epilepsy, and to evaluate differences in these patterns between drug-resistant versus pharmacoresponsive epilepsy. A collection of self-report surveys completed by patients with epilepsy (n = 76) were used to retrospectively compare differences in those with drug-resistant versus pharmacoresponsive epilepsy regarding 1) proportion who used cannabis, 2) frequency of use, 3) method of use, and 4) reason for use. A Cochran-Armitage test for trend indicated that of patients who used cannabis, a higher proportion of patients in the drug-resistant group used more frequently than in the pharmacoresponsive group. Almost half (48%) of those in the drug-resistant group reported daily use compared to approximately a third (36%) of those in the pharmacoresponsive group. Additionally, no patient in either group reported that cannabis was harmful in relation to seizure-related symptoms. Results from this study highlight the need for epilepsy providers to formally assess patients' perceptions and use of non-prescribed cannabis to inform clinical care decisions, particularly in the drug-resistant epilepsy population.

Exploring the genetic etiology of drug-resistant epilepsy: incorporation of exome sequencing into practice

BACKGROUND

By affecting about 50 million people worldwide, epilepsy is considered a global concern in neurology. Intolerable enough, up to ¼ of all patients do not respond to antiepileptic drugs and have recurring seizures. Therefore, revealing the underlying etiology is quite demanding in a clinical context to improve diagnosis and disease management.

METHODS

Initially, 85 patients suspected of epilepsy underwent thorough clinical and paraclinical evaluation and 24 individuals with drug-resistant epilepsy entered the study. Using whole-exome sequencing, the genetic etiology of drug-resistant epilepsy was investigated and discerned whether this method could facilitate the management of drug-resistant epilepsy through personalized medicine. Eventually, functional annotation was performed and drug-gene interaction networks were constructed to find potential therapeutic targets.

RESULTS

We found eleven novel variants in various genes including IRF2BPL, ST3GAL3, and GPAA1, for which a few epilepsy-related variants are available in public databases. The overall diagnostic yield for likely pathogenic and pathogenic variants and the detection rate of novel variants were 25% and 84.6%, respectively. Based on the results, two patients were considered potential candidates for personalized medicine. The highest number of interaction with drugs was demonstrated for SCN1A, SCN2A, and GRIN2A genes.

CONCLUSIONS

This study highlighted the importance of consanguineous marriage in drug-resistant epilepsy and suggested the possibility of reduced penetrance and variable expressivity in some of the autosomal dominant cases. We also suggest that whole-exome sequencing could facilitate personalized management of drug-resistant epilepsy. Regarding drug-gene interactions, some genes such as SCN1A and SCN2A might serve as therapeutic targets in drug-resistant epilepsy.

Utilizing machine learning algorithms to predict subject genetic mutation class from in silico models of neuronal networks

Background

Epilepsy is the fourth-most common neurological disorder, affecting an estimated 50 million patients globally. Nearly 40% of patients have uncontrolled seizures yet incur 80% of the cost. Anti-epileptic drugs commonly result in resistance and reversion to uncontrolled drug-resistant epilepsy and are often associated with significant adverse effects. This has led to a trial-and-error system in which physicians spend months to years attempting to identify the optimal therapeutic approach.

Objective

To investigate the potential clinical utility from the context of optimal therapeutic prediction of characterizing cellular electrophysiology. It is well-established that genomic data alone can sometimes be predictive of effective therapeutic approach. Thus, to assess the predictive power of electrophysiological data, machine learning strategies are implemented to predict a subject’s genetically defined class in an in silico model using brief electrophysiological recordings obtained from simulated neuronal networks.

Methods

A dynamic network of isogenic neurons is modeled in silico for 1-s for 228 dynamically modeled patients falling into one of three categories: healthy, general sodium channel gain of function, or inhibitory sodium channel loss of function. Data from previous studies investigating the electrophysiological and cellular properties of neurons in vitro are used to define the parameters governing said models. Ninety-two electrophysiological features defining the nature and consistency of network connectivity, activity, waveform shape, and complexity are extracted for each patient network and t-tests are used for feature selection for the following machine learning algorithms: Neural Network, Support Vector Machine, Gaussian Naïve Bayes Classifier, Decision Tree, and Gradient Boosting Decision Tree. Finally, their performance in accurately predicting which genetic category the subjects fall under is assessed.

Results

Several machine learning algorithms excel in using electrophysiological data from isogenic neurons to accurately predict genetic class with a Gaussian Naïve Bayes Classifier predicting healthy, gain of function, and overall, with the best accuracy, area under the curve, and F1. The Gradient Boosting Decision Tree performs the best for loss of function models indicated by the same metrics.

Conclusions

It is possible for machine learning algorithms to use electrophysiological data to predict clinically valuable metrics such as optimal therapeutic approach, especially when combining several models.

Interictal Connectivity Revealed by Granger Analysis of Stereoelectroencephalography: Association With Ictal Onset Zone, Resection, and Outcome

BACKGROUND

Stereoelectroencephalography (sEEG) facilitates electrical sampling and evaluation of complex deep-seated, dispersed, and multifocal locations. Granger causality (GC), previously used to study seizure networks using interictal data from subdural grids, may help identify the seizure-onset zone from interictal sEEG recordings.

OBJECTIVE

To examine whether statistical analysis of interictal sEEG helps identify surgical target sites and whether surgical resection of highly ranked nodes correspond to favorable outcomes.

METHODS

Ten minutes of extraoperative recordings from sequential patients who underwent sEEG evaluation were analyzed (n = 20). GC maps were compared with clinically defined surgical targets using rank order statistics. Outcomes of patients with focal resection/ablation with median follow-up of 3.6 years were classified as favorable (Engel 1, 2) or poor (Engel 3, 4) to assess their relationship with the removal of highly ranked nodes using the Wilcoxon rank-sum test.

RESULTS

In 12 of 20 cases, the rankings of contacts (based on the sum of outward connection weights) mapped to the seizure-onset zone showed higher causal node connectivity than predicted by chance ( P ≤ .02). A very low aggregate probability ( P < 10 -18 , n = 20) suggests that causal node connectivity predicts seizure networks. In 8 of 16 with outcome data, causal connectivity in the resection was significantly greater than in the remaining contacts ( P ≤ .05). We found a significant association between favorable outcome and the presence of highly ranked nodes in the resection ( P < .05).

CONCLUSION

Granger analysis can identify seizure foci from interictal sEEG and correlates highly ranked nodes with favorable outcome, potentially informing surgical decision-making without reliance on ictal recordings.

Neuroprotective Effect of Exogenous Galectin-1 in Status Epilepticus

Intrahippocampal pilocarpine microinjection (H-PILO) induces status epilepticus (SE) that can lead to spontaneous recurrent seizures (SRS) and neurodegeneration in rodents. Studies using animal models have indicated that lectins mediate a variety of biological activities with neuronal benefits, especially galectin-1 (GAL-1), which has been identified as an effective neuroprotective compound. GAL-1 is associated with the regulation of cell adhesion, proliferation, programmed cell death, and immune responses, as well as attenuating neuroinflammation. Here, we administrated GAL-1 to Wistar rats and evaluated the severity of the SE, neurodegenerative and inflammatory patterns in the hippocampal formation. Administration of GAL-1 caused a reduction in the number of class 2 and 4 seizures, indicating a decrease in seizure severity. Furthermore, we observed a reduction in inflammation and neurodegeneration 24 h and 15 days after SE. Overall, these results suggest that GAL-1 has a neuroprotective effect in the early stage of epileptogenesis and provides new insights into the roles of exogenous lectins in temporal lobe epilepsy (TLE).

A complex systems view on the current hypotheses of epilepsy pharmacoresistance

Drug-resistant epilepsy remains to this day as a highly prevalent condition affecting around one-third of patients with epilepsy, despite all the research and the development of several new antiseizure medications (ASMs) over the last decades. Epilepsies are multifactorial complex diseases, commonly associated with psychiatric, neurological, and somatic comorbidities. Thus, to solve the puzzling problem of pharmacoresistance, the diagnosis and modeling of epilepsy and comorbidities need to change toward a complex system approach. In this review, we have summarized the sequence of events for the definition of epilepsies and comorbidities, the search for mechanisms, and the major hypotheses of pharmacoresistance, drawing attention to some of the many converging aspects between the proposed mechanisms, their supporting evidence, and comorbidities-related alterations. The use of systems biology applied to epileptology may lead to the discovery of new targets and the development of new ASMs, as may advance our understanding of the epilepsies and their comorbidities, providing much deeper insight on multidrug pharmacoresistance.

Characterization of Cortical Glial Scars in the Diisopropylfluorophosphate (DFP) Rat Model of Epilepsy

Glial scars have been observed following stab lesions in the spinal cord and brain but not observed and characterized in chemoconvulsant-induced epilepsy models. Epilepsy is a disorder characterized by spontaneous recurrent seizures and can be modeled in rodents. Diisopropylfluorophosphate (DFP) exposure, like other real-world organophosphate nerve agents (OPNAs) used in chemical warfare scenarios, can lead to the development of status epilepticus (SE). We have previously demonstrated that DFP-induced SE promotes epileptogenesis which is characterized by the development of spontaneous recurrent seizures (SRS), gliosis, and neurodegeneration. In this study, we report classical glial scars developed in the piriform cortex, but not in the hippocampus, by 8 days post-exposure. We challenged both male and female rats with 4–5 mg/kg DFP (s.c.) followed immediately by 2 mg/kg atropine sulfate (i.m.) and 25 mg/kg pralidoxime (i.m.) and one hour later by midazolam (i.m). Glial scars were present in the piriform cortex/amygdala region in 73% of the DFP treated animals. No scars were found in controls. Scars were characterized by a massive clustering of reactive microglia surrounded by hypertrophic reactive astrocytes. The core of the scars was filled with a significant increase of IBA1 and CD68 positive cells and a significant reduction in NeuN positive cells compared to the periphery of the scars. There was a significantly higher density of reactive GFAP, complement 3 (C3), and inducible nitric oxide synthase (iNOS) positive cells at the periphery of the scar compared to similar areas in controls. We found a significant increase in chondroitin sulfate proteoglycans (CS-56) in the periphery of the scars compared to a similar region in control brains. However, there was no change in TGF-β1 or TGF-β2 positive cells in or around the scars in DFP-exposed animals compared to controls. In contrast to stab-induced scars, we did not find fibroblasts (Thy1.1) in the scar core or periphery. There were sex differences with respect to the density of iNOS, CD68, NeuN, GFAP, C3 and CS-56 positive cells. This is the first report of cortical glial scars in rodents with systemic chemoconvulsant-induced SE. Further investigation could help to elucidate the mechanisms of scar development and mitigation strategies.

Impact of Berberine on Some Epigenetic, Transcription Regulation and Inflammatory Biomarkers in a Mice Model of Epilepsy

Background

Epilepsy is one of the most widespread neurological disease worldwide. Status epilepticus (SE) is a life-threatening neurologic disorder. Neuroprotective approaches are increasingly to discover a promising therapy to manage epileptic disorders. This study aimed to assess the impact of berberine on some epigenetic, transcription regulation & inflammatory biomarkers in a mice model of epilepsy.

Methods

This work was performed on; Group I: (control), Group II: berberine-treated control,Group III: epilepsy group, Group IV: berberine-treated epilepsy. Groups were subjected to assessment of Tumor growth factor-1β (TGF-1β), hypoxia inducible factor-1α (HIF-1α), brain derived neurotrophic factor (BDNF) levels, histone deacetylase (HDAC) activity & neuronal restrictive silencing factor (NRSF) gene expression.

Results

Study showed significant increase in levels of HIF-1α, TGF-1β, HDAC activity & NRSF gene expression in epilepsy group & decrease in these levels in berberine treated epilepsy group. Significant decrease in BDNF levels in epilepsy & elevation in them in berberine treated epilepsy group.

Conclusion

Our study showed the anti-epileptic impact of berberine via its regulatory effect on some epigenetic, transcription factors & inflammatory biomarkers in a mice model of epilepsy.

Characterizing Hippocampal Oscillatory Signatures Underlying Seizures in Temporal Lobe Epilepsy

Temporal Lobe Epilepsy (TLE) is a neurological condition characterized by focal brain hyperexcitability, resulting in abnormal neuronal discharge and uncontrollable seizures. The hippocampus, with its inherently highly synchronized firing patterns and relatively high excitability, is prone to epileptic seizures, and it is usually the focus of TLE. Researchers have identified hippocampal high-frequency oscillations (HFOs) as a salient feature in people with TLE and animal models of this disease, arising before or at the onset of the epileptic event. To a certain extent, these pathological HFOs have served as a marker and a potential target for seizure attenuation using electrical or optogenetic interventions. However, many questions remain about whether we can reliably distinguish pathological from non-pathological HFOs and whether they can tell us about the development of the disease. While this would be an arduous task to perform in humans, animal models of TLE provide an excellent opportunity to study the characteristics of HFOs in predicting how epilepsy evolves. This minireview will (1) summarize what we know about the oscillatory disruption in TLE, (2) summarize knowledge about oscillatory changes in the latent period and their role in predicting seizures, and (3) propose future studies essential to uncovering potential treatments based on early detection of pathological HFOs.

Automatic Electrophysiological Noise Reduction and Epileptic Seizure Detection for Stereoelectroencephalography

The objective of this study was to develop a computational algorithm capable of locating artifacts and identifying epileptic seizures, which specifically implementing in clinical stereoelectroencephalography (SEEG) recordings. Based on the nonstationary nature and broadband features of SEEG signals, a comprehensive strategy combined with the complex wavelet transform (CWT) and multi-layer thresholding method was implemented for both noise reduction and seizure detection. The artifacts removal pipeline integrated edge artifact removal, discrete spectrum analysis, and peak density evaluation. For automatic seizure detection, integrated power analysis and multi-dynamic thresholding were applied. The F1score was applied to evaluate overall performance of the algorithm. The algorithm was tested using expert-marked, double-blinded, clinical SEEG data from seven patients undergoing presurgical evaluation. This approach achieved the F1 score of 0.86 for noise reduction and 0.88 for seizure detection. This offline-approach method with minimum parameter tuning procedures and no prior information required, proved to be a feasible and solid solution for clinical SEEG data evaluation. Moreover, the algorithm can be improved with additional tuning and implemented with machine learning postprocessing pipelines.

A Standardized Electrode Nomenclature for Stereoelectroencephalography Applications

PURPOSE

Stereoelectroencephalography (SEEG) is widely performed on individuals with medically refractory epilepsy for whom invasive seizure localization is desired. Despite increasing adoption in many centers across the world, no standardized electrode naming convention exists, generating confusion among both clinical and research teams.

METHODS

We have developed a novel nomenclature, named the Standardized Electrode Nomenclature for SEEG Applications system. Concise, unique, informative, and unambiguous labels provide information about entry point, deep targets, and relationships between electrodes. Inter-rater agreement was evaluated by comparing original electrode names from 10 randomly sampled cases (including 136 electrodes) with those prospectively assigned by four additional blinded raters.

RESULTS

The Standardized Electrode Nomenclature for SEEG Application system was prospectively implemented in 40 consecutive patients undergoing SEEG monitoring at our institution, creating unique electrode names in all cases, and facilitating implantation design, SEEG recording and mapping interpretation, and treatment planning among neurosurgeons, neurologists, and neurophysiologists. The inter-rater percent agreement for electrode names among two neurosurgeons, two epilepsy neurologists, and one neurosurgical fellow was 97.5%.

CONCLUSIONS

This standardized naming convention, Standardized Electrode Nomenclature for SEEG Application, provides a simple, concise, reproducible, and informative method for specifying the target(s) and relative position of each SEEG electrode in each patient, allowing for successful sharing of information in both the clinical and research settings. General adoption of this nomenclature could pave the way for improved communication and collaboration between institutions.

Centromedian Nucleus and Epilepsy

SUMMARY

Centromedian thalamic nucleus is an intralaminar nucleus with vast connectivity to cerebral cortex and basal ganglia. It receives afferents from the brain stem through the central tegmental tract and is part of the diffuse thalamic projection system. Because the reticulothalamic system has been related to initiation and propagation of epileptic activity (centroencephalic theory of epilepsy), deep brain stimulation has been proposed to interfere with seizure genesis or propagation. Centromedian thalamic nucleus is a large nucleus laying nearby the anatomical references for stereotaxis and therefore a convenient surgical target to approach. Electrodes are implanted in the anterior ventral lateral part of the nucleus (parvocellular area), guided by intraoperative recruiting responses elicited by unilateral 6 to 8 Hz electrical stimulation delivered through the deep brain stimulation electrode. Therapeutic stimulation is delivered with the following parameters: 60 Hz, 450 μs, 3.0 V. Seizure control runs between 69% and 83% in different reports, decreasing mainly generalized seizures from the start, with significant improvement in neuropsychological performance. Significant decrease in seizure occurs from hours to days after the onset of deep brain stimulation. Some reports refer that seizure improvement may occur by the simple insertion of the deep brain stimulation electrodes, and therefore, it was used to treat refractory epileptic status.

Caregiver perspectives on dietary therapies for epilepsy

The objective of this research was to identify caregiver perspectives on dietary therapies for epilepsy, as well as provide future directions for improving caregiver support. A Qualtrics survey was distributed via social media platforms. The survey was aimed towards caregivers with children who are currently using or have previously used dietary therapy for epilepsy. A total of 192 respondents were included, though the number of respondents varied by question. Caregivers reported dietary therapy as 'somewhat to very challenging' with 76% of children and 99% of caregivers reporting at least one difficulty. Eighty percent of caregivers' children experienced at least one type of adverse event, with the most common event being constipation. Finally, caregivers reported high scores for quality of life, happiness with the diet, and feeling supported during treatment. Recommendations for how to improve the experience of families included increased clinic support, support group offerings, meal resources, educational resources, access to diet related equipment, financial assistance/relief, therapy/transition assistance, respect for the caregivers' concerns/thoughts, and restaurant options. In short, most caregivers are pleased with dietary therapy; however, there are specific changes that would significantly help caregivers during treatment. This information could be used by clinics to better support caregivers during treatment.

Epileptogenic Zone Localization in Refractory Epilepsy by FDG-PET: The Comparison of SPM and SPM-CAT With Different Parameter Settings

Refractory epilepsy is a complex case of epileptic disease. The quantitative analysis of fluorodeoxyglucose positron emission tomography (FDG-PET) images complements visual assessment and helps localize the epileptogenic zone (EZ) for better curative treatment. Statistical parametric mapping (SPM) and its computational anatomy toolbox (SPM-CAT) are two commonly applied tools in neuroimaging analysis. This study compares SPM and SPM-CAT with different parameters to find the optimal approach for localizing EZ in refractory epilepsy. The current study enrolled 45 subjects, including 25 refractory epilepsy patients and 20 healthy controls. All of the 25 patients underwent surgical operations. Pathological results and the postoperative outcome evaluation by the Engel scale were likewise presented. SPM and SPM-CAT were used to assess FDG-PET images with three different uncorrected p-values and the corresponding cluster sizes (k), as in voxels in the cluster, namely p < 0.0002, k > 25; p < 0.001, k > 100; p < 0.005, and k > 200. When combining three settings, SPM and SPM-CAT yielded overall positive finding scores of 96.0% (24/25) and 100.0% (25/25) respectively. However, for the individual setting, SPM-CAT achieved the diverse positive finding scores of 96.0% (24/25), 96.0% (24/25), and 88.0% (22/24), which are higher than those of SPM [88.0% (22/25), 76.0% (19/25), and 72.0% (18/25)]. SPM and SPM-CAT localized EZ correctly with 28.0% (7/25) and 64.0% (16/25), respectively. SPM-CAT with parameter settings p < 0.0002 and k > 25 yielded a correct localization at 56.0% (14/25), which is slightly higher than that for the other two settings (48.0 and 20.0%). Moderate concordance was found between the confirmed and pre-surgical EZs, identified by SPM-CAT (kappa value = 0.5). Hence, SPM-CAT is more efficient than SPM in localizing EZ for refractory epilepsy by quantitative analysis of FDG-PET images. SPM-CAT with the setting of p < 0.0002 and k > 25 might perform as an objective complementary tool to the visual assessment for EZ localization.

White Matter Integrity in a Rat Model of Epileptogenesis: Structural Connectomics and Fixel-Based Analysis

Introduction: Electrophysiological and neuroimaging studies have demonstrated that large-scale brain networks are affected during the development of epilepsy. These networks can be investigated by using diffusion magnetic resonance imaging (dMRI). The most commonly used model to analyze dMRI is diffusion tensor imaging (DTI). However, DTI metrics are not specific to microstructure or pathology and the DTI model does not take into account crossing fibers, which may lead to erroneous results. To overcome these limitations, a more advanced model based on multi-shell multi-tissue constrained spherical deconvolution was used in this study to perform tractography with more precise fiber orientation estimates and to assess changes in intra-axonal volume by using fixel-based analysis. Methods: dMRI images were acquired before and at several time points after induction of status epilepticus in the intraperitoneal kainic acid (IPKA) rat model of temporal lobe epilepsy. Tractography was performed, and fixel metrics were calculated in several white matter tracts. The tractogram was analyzed by using the graph theory. Results: Global degree, global and local efficiency were decreased in IPKA animals compared with controls during epileptogenesis. Nodal degree was decreased in the limbic system and default-mode network, mainly during early epileptogenesis. Further, fiber density (FD) and fiber-density-and-cross-section (FDC) were decreased in several white matter tracts. Discussion: These results indicate a decrease in overall structural connectivity, integration, and segregation and decreased structural connectivity in the limbic system and default-mode network. Decreased FD and FDC point to a decrease in intra-axonal volume fraction during epileptogenesis, which may be related to neuronal degeneration and gliosis. Impact statement To the best of our knowledge, this is the first longitudinal multi-shell diffusion magnetic resonance imaging study that combines whole-brain tractography and fixel-based analysis to investigate changes in structural brain connectivity and white matter integrity during epileptogenesis in a rat model of temporal lobe epilepsy. Our findings present better insights into how the topology of the structural brain network changes during epileptogenesis and how these changes are related to white matter integrity. This could improve the understanding of the basic mechanisms of epilepsy and aid the rational development of imaging biomarkers and epilepsy therapies.

Efficacy and safety of levetiracetam as adjunctive therapy for refractory focal epilepsy

BACKGROUND

Epilepsy affects about 50 million people worldwide and around 30% of these patients have refractory epilepsy, with potential consequences regarding quality of life, morbidity and premature mortality.

OBJECTIVE

The aim of treatment with antiseizure medications (ASMs) is to allow patients to remain without seizures, with good tolerability. Levetiracetam is a broad-spectrum ASM with a unique mechanism of action that differs it from other ASMs. It has been shown to be effective and safe for treating adults and children with epilepsy.

METHODS

This was a phase III, multicenter, randomized, double-blind, placebo-controlled trial to evaluate the efficacy and safety of levetiracetam in children and adults (4-65 years) as an adjuvant treatment for focal-onset seizures. It was conducted among 114 patients undergoing treatment with up to three ASMs. The primary efficacy analysis was based on the proportion of patients who achieved a reduction of ≥ 50% in the mean number of focal seizures per week, over a 16-week treatment period. The patients were randomized to receive placebo or levetiracetam, titrated every two weeks from 20 mg/kg/day or 1,000 mg/day up to 60 mg/kg/day or 3,000 mg/day.

RESULTS

Levetiracetam was significantly superior to placebo (p = 0.0031); 38.7% of the participants in the levetiracetam group and 14.3% in the control group shows reductions in focal seizures. Levetiracetam was seen to have a favorable safety profile and an adverse event rate similar to that of placebo.

CONCLUSION

Corroborating the results in the literature, levetiracetam was shown to be effective and safe for children and adults with refractory focal-onset epilepsy.

Hippocampal CA3 transcriptional modules associated with granule cell alterations and cognitive impairment in refractory mesial temporal lobe epilepsy patients

In about a third of the patients with epilepsy the seizures are not drug-controlled. The current limitation of the antiepileptic drug therapy derives from an insufficient understanding of epilepsy pathophysiology. In order to overcome this situation, it is necessary to consider epilepsy as a disturbed network of interactions, instead of just looking for changes in single molecular components. Here, we studied CA3 transcriptional signatures and dentate gyrus histopathologic alterations in hippocampal explants surgically obtained from 57 RMTLE patients submitted to corticoamygdalohippocampectomy. By adopting a systems biology approach, integrating clinical, histopathological, and transcriptomic data (weighted gene co-expression network analysis), we were able to identify transcriptional modules highly correlated with age of disease onset, cognitive dysfunctions, and granule cell alterations. The enrichment analysis of transcriptional modules and the functional characterization of the highly connected genes in each trait-correlated module allowed us to unveil the modules’ main biological functions, paving the way for further investigations on their roles in RMTLE pathophysiology. Moreover, we found 15 genes with high gene significance values which have the potential to become novel biomarkers and/or therapeutic targets in RMTLE.

Interneuron transplantation: a prospective surgical therapy for medically refractory epilepsy

Excitatory-inhibitory imbalance is central to epilepsy pathophysiology. Current surgical therapies for epilepsy, such as brain resection, laser ablation, and neurostimulation, target epileptic networks on macroscopic scales, without directly correcting the circuit-level aberrations responsible for seizures. The transplantation of inhibitory cortical interneurons represents a novel neurobiological method for modifying recipient neural circuits in a physiologically corrective manner. Transplanted immature interneurons have been found to disperse in the recipient brain parenchyma, where they develop elaborate structural morphologies, express histochemical markers of mature interneurons, and form functional inhibitory synapses onto recipient neurons. Transplanted interneurons also augment synaptic inhibition and alter recipient neural network synchrony, two physiological processes disrupted in various epilepsies. In rodent models of epilepsy, interneuron transplantation corrects recipient seizure phenotypes and associated behavioral abnormalities. As such, interneuron transplantation may represent a novel neurobiological approach to the surgical treatment of human epilepsy. Here, the authors describe the preclinical basis for applying interneuron transplantation to human epilepsy, discuss its potential clinical applications, and consider the translational hurdles to its development as a surgical therapy.

Sleep profile and Polysomnography in patients with drug-resistant temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS) and the effect of epilepsy surgery on sleep-a prospective cohort study

OBJECTIVES

We analyzed changes in sleep profile and architecture of patients with drug-resistant TLE-HS using three validated sleep questionnaires- Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), NIMHANS Comprehensive Sleep Disorders, and polysomnography (PSG). We studied the effect of epilepsy surgery in a subset of patients.

METHODS

In this prospective observational cohort study, sleep profile of 40 patients with drug-resistant TLE-HS was compared to 40 healthy matched controls. Sleep architecture of 22 patients was studied by overnight PSG and compared to 22 matched controls. Sleep profile was reassessed in 20 patients after a minimum period of three months after epilepsy surgery.

RESULTS

The mean PSQI was higher among patients compared to controls(P=0.0004) while mean ESS showed no difference. NCSDQ showed fewer patients feeling refreshed after a night's sleep compared to controls (p=0.006). PSG revealed a higher time in bed (p=0.0001), longer total sleep time (p=0.006) and more time spent in NREM stage 1 (p=0.001) and stage 2 (p=0.005) while spending less time in stage 3 (p=0.039) among TLE patients. Sleep efficiency was worse in patients on ≥3 ASMs compared to those on 2 ASMs (p-0.044). There was no change in mean ESS (p=0.48) or PSQI (p=0.105) after surgery.

CONCLUSIONS

Patients with drug-resistant TLE-HS have an altered sleep profile and architecture. Patients on ≥3 ASMs have a lower sleep efficiency. Reassessment at short intervals after epilepsy surgery did not reveal significant changes in sleep profile.

Does Stress Trigger Seizures? Evidence from Experimental Models

This chapter describes the experimental evidence of stress modulation of epileptic seizures and the potential role of corticosteroids and neurosteroids in regulating stress-linked seizure vulnerability. Epilepsy is a chronic neurological disorder that is characterized by repeated seizures. There are many potential causes for epilepsy, including genetic predispositions, infections, brain injury, and neurotoxicity. Stress is a known precipitating factor for seizures in individuals suffering from epilepsy. Severe acute stress and persistent exposure to stress may increase susceptibility to seizures, thereby resulting in a higher frequency of seizures. This occurs through the stress-mediated release of cortisol, which has both excitatory and proconvulsant properties. Stress also causes the release of endogenous neurosteroids from central and adrenal sources. Neurosteroids such as allopregnanolone and THDOC, which are allosteric modulators of GABA-A receptors, are powerful anticonvulsants and neuroprotectants. Acute stress increases the release of neurosteroids, while chronic stress is associated with severe neurosteroid depletion and reduced inhibition in the brain. This diminished inhibition occurs largely as a result of neurosteroid deficiencies. Thus, exogenous administration of neurosteroids (neurosteroid replacement therapy) may offer neuroprotection in epilepsy. Synthetic neurosteroid could offer a rational approach to control neurosteroid-sensitive, stress-related epileptic seizures.

Effects of prednisolone on behavioral and inflammatory profile in animal model of PTZ-induced seizure

Epilepsy is a chronic neurological condition that affects 1%-2% of the world population. Although research about the disease is advancing and a wide variety of drugs is available, about 30 % of patients have refractory epilepsy which cannot be controlled with the most common drugs. This highlights the need for a better understanding of the disorder and new types of treatment for it. Against this backdrop, a growing body of evidence has reported that inflammation may play a role both in the origin and in the progression of seizures. It has shown a tendency to be both the root and the result of epilepsy. This investigation aimed to assess the impact of prednisolone, a steroidal anti-inflammatory drug, in an animal model of pentylenetetrazole (PTZ)-induced seizures, at 1 mg/kg and 5 mg/kg doses. We also examined the degree of seizure severity and the modulation of pro-inflammatory cytokines in the treated animals. Four treatment groups were used (saline, diazepam, prednisolone 1 mg/kg, and prednisolone 5 mg/kg) and, in addition to their own daily treatments, subconvulsant doses of pentylenetetrazole (25 mg/kg) were administered every other day during a test protocol that lasted 14 days. After treatment, the cytokines interleukin 1 beta (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) were measured in the animals' sera, hippocampi, and prefrontal cortices. Animals treated with prednisolone presented less severe seizures than the animals in the saline group, and there was a decrease in pro-inflammatory cytokine levels in central structures, but not peripheral ones. In short, an animal model of chemically-induced epileptic seizures was used, in which the animals were treated with doses of prednisolone, and these animals presented less severe seizures than the negative control group (saline), in addition to showing decreased levels of pro-inflammatory cytokines IL-6, IL-1β and TNF-α, in the hippocampi and prefrontal cortices, but not the sera.

Gut Microbiota and Epilepsy: A Systematic Review on Their Relationship and Possible Therapeutics

Dysbiosis of gut microbiota may lead to a range of diseases including neurological disorders. Thus, it is hypothesized that regulation of the intestinal microbiota may prevent or treat epilepsy. The purpose of this systematic review is to evaluate the evidence investigating the relationship between gut microbiota and epilepsy and possible interventions. A systematic review of the literature was done on four databases (PubMed, Scopus, EMBASE, and Web of Science). Study selection was restricted to original research articles while following the PRISMA guidelines. Six studies were selected. These studies cohesively support the interaction between gut microbiota and epileptic seizures. Gut microbiota analysis identified increases in Firmicutes, Proteobacteria, Verrucomicrobia, and Fusobacteria with decreases in Bacteroidetes and Actinobacteria in epileptic patients. Ketogenic diet, probiotics, and fecal microbiota transplantation (FMT) improved the dysbiosis of the gut microbiota and seizure activity. However, the studies either had a small sample size, lack of subject variability, or short study or follow-up period, which may question their reliability. Nevertheless, these limited studies conclusively suggest that gut microbiota diversity and dysbiosis may be involved in the pathology of epilepsy. Future studies providing more reliable and in depth insight into the gut microbial community will spark promising alternative therapies to current epilepsy treatment.

Optimizing data collection in dietary therapy clinics for epilepsy: A recommendation for standardized data collection forms

OBJECTIVE

The objectives of this study were to 1) examine medical records from one medium-sized dietary clinic as an example of data being collected clinically, 2) identify data limitations, and then 3) create standardized data collection forms with the long-term goals of improving clinical care and facilitating multicenter data analysis.

METHODS

A retrospective chart review was conducted at the Dietary Therapies for Epilepsy Clinic at Children's National Medical Center (CNMC) in Washington, D.C. Patients who initiated dietary therapy between 2015 and 2018 were assessed. Categorical variables were examined via Chi Square or Fisher's Exact tests and continuous variables were assessed via an independent t-test or Mann-Whitney U test, depending on normality.

RESULTS

Forty-two patients underwent dietary therapy initiation during this time period, but only 26 had follow-up visit data. Of these patients, 54% reported non-seizure symptom improvement(s), and only 16 had quantitative seizure frequency information available, with 63% being clinical responders. No significant associations were observed between patient or diet characteristics and seizure or non-seizure improvement. Some variables, such as seizure duration, seizure severity, beta-hydroxybutyrate, and dietary compliance were not typically included in the records and therefore could not be evaluated statistically. Variations in seizure type(s), etiology, and clinical diagnoses/syndromes also made it unfeasible to evaluate differences in improvement based on these variables. Standardized data collection forms were created to address these limitations and are included as appendices.

SIGNIFICANCE

The results suggest limitations with the clinical data currently being collected. Medium-sized clinics may not see enough patients to study specific epilepsy populations. Standardized patient forms could target these issues, thereby improving clinical care and expanding research opportunities. Future research can test these forms for clinical use and as a collection tool for larger scale research across clinics.

Characterization of the Expression of the ATP-Gated P2X7 Receptor Following Status Epilepticus and during Epilepsy Using a P2X7-EGFP Reporter Mouse

Mounting evidence suggests that the ATP-gated P2X7 receptor contributes to increased hyperexcitability in the brain. While increased expression of P2X7 in the hippocampus and cortex following status epilepticus and during epilepsy has been repeatedly demonstrated, the cell type-specific expression of P2X7 and its expression in extra-hippocampal brain structures remains incompletely explored. In this study, P2X7 expression was visualized by using a transgenic mouse model overexpressing P2X7 fused to the fluorescent protein EGFP. The results showed increased P2X7-EGFP expression after status epilepticus induced by intra-amygdala kainic acid and during epilepsy in different brain regions including the hippocampus, cortex, striatum, thalamus and cerebellum, and this was most evident in microglia and oligodendrocytes. Co-localization of P2X7-EGFP with cell type-specific markers was not detected in neurons or astrocytes. These data suggest that P2X7 activation is a common pathological hallmark across different brain structures, possibly contributing to brain inflammation and neurodegeneration following acute seizures and during epilepsy.

A Novel Approach to Refractory Epilepsy by Targeting Pgp Peripherally and Centrally: Therapeutic Targets and Future Perspectives

Refractory epilepsy is a type of epilepsy involving seizures uncontrolled by first or second- line anticonvulsant drugs at a regular therapeutic dose. Despite considerable growth in epileptic pharmacotherapy, one-third of the patients are resistant to current therapies. In this, the mechanisms responsible for resistant epilepsy are either increased expulsion of antiepileptic drugs (AEDs) by multidrug resistance (MDR) transporters from the epileptogenic tissue or reduced sensitivity of drug in epileptogenic brain tissue. The difficulty to treat refractory epilepsy is because of drug resistance due to cellular drug efflux, use of drug monotherapy, and subtherapeutic dose administration. Increased expression of Pgp is also responsible for resistance epilepsy or refractory epilepsy. Increased glutamate expression via inhibition of cyclooxygenase-II (COX-II) enzyme also upregulate P-glycoprotein (Pgp) expression and augment instance of recurrent seizures. Peripheral and central inhibition of Pgp is a powerful tool to control this drug resistant epilepsy. Drug resistance primarily involves multidrug resistance (MDR1) gene responsible for encoding P-glycoprotein (Pg- P1 or MDR1). Currently, there is no drug under clinical practice which inhibits MDR1. The present review cites some drugs like Calcium Channel Blockers (CCBs), COX-II inhibitors, and glutamate receptors antagonists that inhibit P-gp. The exploitation of these targets may emerge as a beneficial approach for patients with drug-resistant epilepsy. The present review further highlights the mechanistic role of Pgp in drug-resistant epilepsy, glutamate role in drug efflux, and management approach.

Synthesis, Antibacterial Activity and Molecular Docking Studies of New Pyrazole Derivatives

Background:

The pyrazole structure is an important heterocyclic structure and plays critical roles in agriculture, industrial and medicine. Furthermore, compounds containing pyrazole are known to exhibit various biological properties such as antibacterial, antifungal, anticancer, antiinflammatory, antidepressant, antipyretic, antiviral, anti-tubercular and anti-HIV activities. Because of these properties, pyrazole molecules have become a very popular topic for organic chemists.

Methods:

A series newly substituted pyrazole molecules were synthesized and characterized. Their antimicrobial activities were investigated by disk diffusion method against some gram positive bacteria and gram negative bacteria.

Results:

The present results indicated that the some test compounds were active in a broad spectrum against important human pathogenic microorganisms. The substituted pyrazoles including carbazone (7a, b) and thiazolidine (8a, b) showed a wide variety of biological activities. The results showed that synthesized pyrazole, compounds 7b and 8b are highly active and more potent in both biological and molecular docking simulation studies.

Conclusion:

The synthesized pyrazole molecules showed moderate antibacterial activities against the tested microorganism compared to antibiotic drug. Some test compounds (7b and 8b) might be used as new antibacterial agents.