The current place of epilepsy surgery

A prospective cohort study estimating total pre-surgical healthcare costs before and two-year total societal costs after resective brain surgery, and quality of life of patients with drug-resistant epilepsy undergoing surgery

BACKGROUND

In contrast to clinical effectiveness of resective epilepsy surgery (RES) for patients with drug-resistant epilepsy, societal costs of RES is still unclear. The aim of this study was to report on total societal costs up until two years after surgery and analyse the trend of post-surgical costs over time. Secondary objectives included assessing quality of life (QoL) changes and identifying determinants of post-surgical costs.

METHODS

Data were derived from the patients' entire medical history based on hospital files and accompanied by validated questionnaires before and 3-, 6-, 12-, and 24-months post-surgery to additionally include medical consumption outside of the hospital, productivity losses and gains, and QoL. To explore the trend of post-surgical costs over time and identify determinants of post-surgical costs, linear mixed effects and linear regression models were performed.

RESULTS

The study included 44 patients. Mean complete costs from diagnostics and treatment strategies in the period before referral for pre-surgical evaluation up until two years after RES were €121,856 (Interquartile range = €76,058-€137,027). Post-surgical costs significantly decreased 12 months (mean 3-month difference = €-6,675, p = 0.000) and 24 months (mean 3-month difference = €-7,690, p = 0.000) after surgery compared to 3 months before surgery. Higher post-surgical costs were associated with a clinically relevant increase in disease-specific QoL after RES (p = 0.000), previous ketogenic diet (p = 0.005), RES in the left hemisphere (p = 0.014), previous RES (p = 0.007), and higher diagnostics and treatment strategies costs before referral for pre-surgical evaluation (p = 0.021). For disease-specific and generic QoL, 20 (45%) patients reached a clinically relevant QoL increase two years after surgery compared to before RES.

CONCLUSION

In conclusion, RES leads to significant reduction in costs 2 years post-surgery. History of RES and ketogenic diet, clinically relevant disease-specific QoL increase, surgery in the left hemisphere, and higher costs of diagnostics and treatment strategies before referral for pre-surgical evaluation were significant determinants for higher post-surgical costs after RES.

ESR Essentials: Image evaluation of patients with seizures and epilepsy-practice recommendations by the European Society of Neuroradiology

Epilepsy, a neurological disorder characterised by recurrent seizures, poses significant challenges in diagnosis, treatment, and management. Understanding the underlying causes and identifying precise anatomical locations of epileptogenic foci are critical for effective management strategies, particularly in drug-resistant patients. Neuroimaging techniques, particularly magnetic resonance (MR), play a pivotal role in the evaluation of epilepsy patients, offering insights into structural abnormalities, epileptogenic lesions, and functional alterations within the brain. Diverse clinical scenarios that warrant neuroimaging in epilepsy patients, ranging from first-onset seizures to drug-resistant epilepsy, will be presented, elucidating the considerations and recommendations for imaging modalities. The dedicated MR protocol for epilepsy patients will be discussed, justifying the rationale behind sequence selection and optimisation strategies and providing clues about how to read these magnetic resonance imaging (MRI) exams. Finally, MR findings associated with common epileptogenic lesions, such as hippocampal sclerosis, focal cortical dysplasia, and long-term epilepsy-associated tumours, will be described. This article reviews essential concepts, including definitions, classification, imaging indications, protocols, and neuroradiological findings, aiming to understand how neuroimaging contributes to diagnosing and managing epilepsy comprehensively. KEY POINTS: MR should be performed in adults and children with a recent diagnosis of epilepsy of unknown aetiology, a first seizure, and a negative CT. Performing a dedicated MR protocol in focal epilepsy is essential for increasing the detection of potentially epileptogenic lesions. For presurgical evaluations, MR abnormalities should correlate with the electric pattern, semiology data, or other neuroimaging examination to be considered the epileptogenic lesion.

Sociodemographic barriers in epilepsy surgery in the United States: A systematic review and meta-analysis

OBJECTIVES

The aim of this study was to perform a systematic review and meta-analysis to identify sociodemographic barriers that could contribute to the underutilization of epilepsy surgery.

METHODS

PubMed, EMBASE, and Web of Science databases were systematically reviewed from January 2002 until August 2024. The studies examining the impact of sociodemographic barriers on epilepsy surgery were included. The primary outcomes were the odds ratio (OR) and 95 % confidence intervals (CI) for receiving surgery compared to not-receiving surgery in persons with epilepsy. Race/ethnicity, sex, and insurance had sufficient data to perform a meta-analysis of OR and 95 % CI.

RESULTS

Overall, 1,520,813 patients from 12 studies were evaluated, among which relevant studies were selected for comparing sex (338,170 males and 341,821 females), race (1,056,571 White, 224,693 Hispanic, and 239,549 Black/African-American [Black/AA]), and insurance (232,908 private, 190,849 Medicaid, and 204,478 Medicare). Black/AA patients were significantly less likely to have surgery compared to Whites (OR 0.46, CI 0.35-0.61) or Hispanics (OR: 0.54, CI 0.43-0.67). White patients were more likely to have surgery than other groups examined (OR 1.61, CI 1.28-2.02). There were no significant differences in surgical odds when comparing males to females (OR 1.00, CI 0.97-1.03). Compared to the private insurance, patients with Medicaid (OR 0.61, CI 0.49-0.75) or Medicare (OR: 0.49, CI 0.32-0.77) were less likely to obtain surgery.

CONCLUSION

This meta-analysis highlights the impact of race/ethnicity, sex, and insurance status in the likelihood of receiving epilepsy surgery and can inform targeted interventions and policies aimed at ensuring equity for disadvantaged groups.

Ultrabright ratiometric Raman-guided epilepsy surgery by intraoperatively visualizing proinflammatory microglia

Resective surgery is an effective approach for long-term seizure control in drug-resistant focal epilepsy when the epileptic focus (EF) can be accurately delineated and removed. However, intraoperative mapping of EF with electrocorticography is laborious, time-consuming, and highly vulnerable to the effects of anesthesia. Here, we demonstrated that activated microglia can be reliable biomarkers for EF localization. Leveraging a newly developed ratiometric Raman nanosensor, ultraHOCls, we successfully visualize proinflammatory microglia in live epileptic mice, allowing for precise EF delineation without the interference of anesthesia. Compared to electrocorticography-guided surgery, ultraHOCl-guided surgery results in a substantial 61% reduction in total seizure burden in epileptic mouse models. Notably, ultraHOCls sprayed on freshly excised human brain tissues can effectively discriminate epileptic regions from non-epileptic tissues with high sensitivity (94.89%) and specificity (93.3%). This work provides an alternative strategy for delineating the EF intraoperatively, potentially revolutionizing surgery outcomes in epilepsy patients.

Phase-amplitude coupling within MEG data can identify eloquent cortex

Objective.Proper identification of eloquent cortices is essential to minimize post-surgical deficits in patients undergoing resection for epilepsy and tumors. Current methods are subjective, vary across centers, and require significant expertise, underscoring the need for more objective pre-surgical mapping. Phase-amplitude coupling (PAC), the interaction between the phase of low-frequency oscillations and the amplitude of high-frequency activity, has been implicated in task-induced brain activity and may serve as a biomarker for functional mapping. Our objective was to develop a novel PAC-based algorithm to non-invasively identify somatosensory eloquent cortex using magnetoencephalography (MEG) data in epilepsy patients.Approach.We analyzed somatosensory and spontaneous MEG recordings from 30 subjects with drug-resistant epilepsy. PAC was calculated on source-reconstructed data (5-12 Hz for low frequencies and 30-300 Hz for high frequencies), followed by rank-2 tensor decomposition. Density-based clustering compared active brain regions during somatosensory task and spontaneous data at a population level. We employed a linear mixed-effects model to quantify changes in PAC between somatosensory and resting-state data. We developed a patient-specific support vector machine (SVM) classifier to identify active brain regions based on PAC values during the somatosensory task.Main results.Five of six expected brain regions were active during left and right-sided stimulation (p=1.08×10-8, hypergeometric probability test). The mixed-effects model confirmed task-specific PAC in anatomically relevant brain regions (p < 0.01). The SVM classifier gave a specificity of 99.46% and a precision of 66.9%. These results demonstrate that the PAC algorithm reliably identifies somatosensory cortex activation at both individual and population levels with statistical significance.Significance.This study demonstrates the feasibility of using PAC as a non-invasive marker for identifying functionally relevant brain regions during somatosensory task in epilepsy patients. Future work will evaluate its applicability for mapping other eloquent cortices, including language, motor, and auditory areas.

Classifying High-Frequency Oscillations by Morphologic Contrast to Background, With Surgical Outcome Correlates

PURPOSE

Ictal high-frequency oscillations (HFOs) are a reliable indicator of a seizure onset zone for intracranial EEG recordings. Interictal HFOs often are also observed and may be a useful biomarker to supplement ictal data, but distinguishing pathologic from physiologic HFOs continues to be a challenging task. We present a method of classifying HFOs based on morphologic contrast to the background.

METHODS

We retrospectively screened 31 consecutive patients who underwent intracranial recordings for epilepsy at Stanford Medical Center during a 2-year period, and 13 patients met the criteria for inclusion. Interictal EEG data were analyzed using an automated event detector followed by morphologic feature extraction and k-means clustering. Instead of only using event features, the algorithm also incorporated features of the background adjacent to the events. High-frequency oscillations with higher morphologic contrast to the background were labeled as pathologic, and "hotspots" with the most active pathologic HFOs were identified and compared with clinically determined seizure onset zones.

RESULTS

Clustering with contrast features produced groups with better separation and more consistent boundaries. Eleven of the 13 patients proceeded to surgery, and patients whose hotspots matched seizure onset zones had better outcomes, with 4 out of 5 "match" patients having no disabling seizures at 1+ year postoperatively (Engel I or International League Against Epilepsy Class 1-2), while all "mismatch" patients continued to have disabling seizures (Fisher exact test P -value = 0.015).

CONCLUSIONS

High-frequency oscillations with higher contrast to background more likely represent paroxysmal bursts of pathologic activity. Patients with HFO hotspots outside of identified seizure onset zones may not respond as well to surgery.

Transorbital Transsylvian Selective Amygdalohippocampectomy: A Feasibility Anatomic Investigation

BACKGROUND AND OBJECTIVES

Several surgical techniques have been developed to treat mesial temporal lobe epilepsy, the most common form of drug-resistant epilepsy. Although surgical treatment for mesial temporal lobe epilepsy has proven to be highly effective in controlling seizures and improving patients' quality of life, it carries potential risk to critical neurovascular structures, which can result in significant complications. With the advent of endoscopic techniques, the transorbital route has emerged as a potential alternative for mesial temporal lobe surgery. This study aims to assess the feasibility, potential advantages, and disadvantages of the transorbital transsylvian selective amygdalohippocampectomy (TTSA) and to provide a step-by-step anatomic description of this approach.

METHODS

A TTSA was performed on three injected cadaveric specimens (six sides). Computer tomography and MRI scans were performed before and after each dissection to demonstrate the extent of amygdalohippocampectomy. Neuronavigation was used to identify the optimal trajectory and the position of intra-axial structures, including the amygdala and hippocampus. For each side, a TTSA was performed and all the anatomic landmarks verified from the standard transcranial perspective through a frontotemporal craniotomy.

RESULTS

The dissection procedure was organized into four sequential steps: (1) the extradural approach, (2) identification and opening of the sylvian fissure, (3) identification and removal of the amygdala, and (4) identification and removal of the hippocampus and parahippocampal gyrus. The intradural steps were performed in accordance with the technique described by Yasargil. Furthermore, a unique and educational comparison between the transorbital anatomic view and the related standard transcranial perspective was provided.

CONCLUSION

The described technique represents an innovative and feasible approach for amygdalohippocampectomy, achieving comparable surgical resection with traditional open surgery in cadaveric specimens, with potential advantages for neurological and neuropsychological outcomes. However, clinical series and further studies are imperative to validate these findings.

Epilepsy

Epilepsy is a common neurologic condition characterized by at least 1 unprovoked seizure and a high risk for recurrent seizures. Distinguishing epilepsy from conditions that can mimic seizures is important for accurate diagnosis and effective treatment. This article reviews the evaluation of patients suspected of having epilepsy and discusses behavioral strategies and pharmacologic and surgical therapies that can help reduce morbidity associated with recurrent seizures.

Epilepsy Surgery for Drug-Resistant Epilepsy in Africa: A Systematic Review

BACKGROUND AND OBJECTIVES

Nearly one-third of individuals with epilepsy have drug-resistant epilepsy, treated most effectively with surgery. This study aims to discuss the demographic profile, surgical access, and strategies used in drug-resistant epilepsy in Africa.

METHODS

A systematic review was performed using PubMed, Google Scholar, Embase, and Web of Science in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

RESULTS

Nine studies encompassing 498 patients from 6 African countries (Egypt, Kenya, Morocco, South Africa, Tunisia, and Uganda) were included. The mean Methodological Index for Non-Randomized Studies score for these articles was 9.6 ± 1.6. The average patient age was 24.9 years (95% CI: 18.9-30.8 years), with a male predominance of 53.4%. The average age of seizure onset was 10.4 years (95% CI: 6.1-14.7 years). Most patients experienced focal onset seizures (73.1%), with head trauma (33.1%) being the most reported risk factor. The predominant etiologies were hippocampal sclerosis (66.8%, 95% CI: 42.7-91), microdysgenesis (26.7%, 95% CI: 20.7-32.7), and brain tumors (22.3%, 95% CI: 6.4-38.2). Lesions were primarily located in the left hemisphere (61.9%, 95% CI: 26.7-97.1), with temporal lobe involvement in 54.8% of cases (95% CI: 28.7-80.8). Temporal lobectomy was the most frequently performed surgery (59.6%), followed by lesionectomy (9.6%). Postoperatively, 80.6% of patients achieved Engel class I outcomes, indicating seizure freedom, and long-term follow-up (1 to 5 years) showed that 70.3% maintained Engel class I outcomes. Surgical complications were reported in 8.8% of cases.

CONCLUSION

These findings demonstrate the efficacy and long-term benefits of epilepsy surgery in Africa, where epilepsy is a significant public health challenge. The high rates of seizure freedom and reduced seizure frequency from surgery highlight its potential to improve the quality of life for individuals with drug-resistant epilepsy in Africa.

Nucleus accumbens shell electrical lesion attenuates seizures and gliosis in chronic temporal lobe epilepsy rats

OBJECTIVE

Temporal lobe epilepsy (TLE) is the most prevalent form of epilepsy. Prior research has indicated the involvement of the nucleus accumbens shell (NAcSh) in the process of epileptogenesis, thereby implying its potential as a therapeutic target for TLE. In the present study, we investigated the antiepileptic effect of the NAcSh electrical lesion.

METHODS

Chronic TLE was induced by stereotactic injection of kainic acid (KA) into the hippocampus 3 weeks after KA administration, and NAcSh electrical lesions were performed. Seizures in rats were monitored by video electroencephalogram (EEG) 1 week following the NAcSh electrical lesion. Besides, the spatial memory function assessment in rats was conducted using the Morris water maze (MWM) test in the final week of the experiment. Later, hippocampal glial cell activation and neuron loss in rats were evaluated through immunohistochemistry.

RESULTS

TLE rats subjected to NAcSh electrical lesion exhibited a significant reduction in the frequency of seizures compared to untreated TLE rats. Furthermore, NAcSh electrical lesion led to less activation of hippocampal glial cells and fewer neuronal loss in TLE rats. It is worth noting that the NAcSh electrical lesion did not cause additional memory impairment.

SIGNIFICANCE

In the present study, the NAcSh electrical lesion exhibited a definitive therapeutic effect on the chronic TLE rat model, potentially due to decreased hippocampal TLE-induced activation of glial cells and neuron loss. In conclusion, our results indicated that the NAcSh is a promising therapeutic target for TLE and possesses high potential for clinical application.

Controllability of nonlinear epileptic-seizure spreading dynamics in large-scale subject-specific brain networks

Closed-loop electrical stimulation has become an important alternative to resective surgery for control of pharmacologically-resistant focal epileptic seizures. Seizure spread across large-scale brain networks, rather than its focal onset, is what commonly leads to major disruptions in sensorimotor and cognitive processing, as well as loss-of-consciousness, one of the main impairing aspects of the disorder. Electrical stimulation, triggered by early detection of seizure onset in epileptogenic zones (EZs), has been applied to prevent spread and its subsequent effects. Here, we show how linear feedback seizure-spread controllability in subject-specific (white-matter tractography) Epileptor network models is affected by variations in brain excitability, network coupling strength, control latency and gain, and actuation targets. Feedback control can qualitatively change the nonlinear seizure dynamics, and the paths to seizure termination and spread prevention. Notably, control onset latency is a critical parameter leading to a phase transition in spread controllability. Consequently, the efficacy of EZ-only actuation is limited depending on network excitability, coupling strength, and practical latencies for detection and actuation. Additional feedback-stabilization control of theoretically-derived optimal node subsets in the network are necessary for spread prevention. Finally, we contrast our linear-feedback controllability assessment with other measures based on minimum-energy (Gramian) controllability and nonlinear pulse-perturbation approaches.

Epilepsy Surgery Education: A Survey of US Epilepsy Fellowship Program Directors

PURPOSE

To understand the current state of epilepsy surgery education delivered to epilepsy fellows in the United States.

METHODS

An online survey focused on characteristics of epilepsy surgery education was distributed to all 93 epilepsy fellowship program directors listed on the ACGME website (accessed in May 2022). Programs were stratified per the number of fellows currently enrolled: 0 to 3 (group A) and ≥4 (group B).

RESULTS

Forty-one of 93 (44%) epilepsy fellowship programs were included in the study. The average number of resective surgeries, ablations, or corpus callosotomies per year was mostly 0 to 30 (54%) in group A and mostly >30 (80%) in group B (P = 0.05). The average number of intracranial implantations per year was mostly 0 to 20 (58%) in group A and mostly >20 (80%) in group B (P < 0.05). The average number of neurostimulation implantations per year was 15 (range 0-90; vagal nerve stimulation), 7 (range 0-25; responsive neurostimulation), and 4 (range 0-10; deep brain stimulation). In 78% of programs, fellows are not required to present a minimum number of epilepsy surgery cases in multidisciplinary conference before graduation. Roughly half of programs (51%) reported not using objective measures to assess fellow competency in epilepsy surgery.

CONCLUSIONS

Our results suggest significant variability in epilepsy surgery volume and, consequently, fellow exposure to surgical cases and lack of standardized, objective measures in fellow teaching and assessment in the field of epilepsy surgery across programs in the United States. We advocate development of a core epilepsy surgery curriculum including minimum standards at the national level.

National trends of Laser interstitial thermal therapy (LITT) and Vagus Nerve stimulation (VNS) for refractory epilepsy in adult patients: A Nationwide Inpatient Sample based propensity score matched analysis

OBJECTIVE

The aim of our study was to report the national trends of Vagus nerve stimulation (VNS) and Laser interstitial thermal therapy (LITT) and compare their outcomes in patients with medically refractory epilepsy (RE).

METHODS

Nationwide Inpatient Sample database (NIS, 1998-2018) was used to extract the data using the ICD-9/10 codes. Adult patients (>18 years) with a primary diagnosis of RE who underwent either VNS or LITT were included. Patient demographics, complications, length of hospital stay (LOS), discharge disposition and index-hospitalization costs were analyzed.

RESULTS

A cohort of 226,248 patients with RE were included, of which only 0.66 % underwent VNS (n = 1500) and 0.34 % (n = 770) underwent LITT. VNS accounted for 66 % of the surgical procedures. The use of LITT gradually increased from 2012 (0.69/1000 RE cases) to 2018 (4.43/1000 RE cases) compared to VNS (2012: 9.85/1000 RE to 2018: 5.31/1000 RE cases). Median age was similar across the cohorts (LITT: 38 years; VNS: 36 years, p = 0.33). Index hospitalization median charges were significantly lower following LITT compared to VNS (LITT: $ 115,838; VNS: $ 131,984, p < 0.0033). No differences in terms of median LOS, discharge to home, complications and median index hospitalization charges were noted between the procedures (LITT vs. VNS).

CONCLUSION

LITT is increasingly being performed for RE with decreasing trends for VNS. The complications profile was similar among both the procedures. Both LITT and VNS are minimally invasive and safe treatment modalities in carefully selected patients with RE.

Surgery for Medication Refractory Epilepsy in Africa: A Review of Seizure Freedom Outcomes

BACKGROUND

Epilepsy is a chronic condition that confers social stigma, reduced engagement in work and social activities, increased risks of comorbidities, and premature death. It is often treated with medications, but in about a third of patients, epilepsy may be refractory to medications. It is estimated that each year 211,456 new individuals across Africa meet criteria for surgically treatable epilepsy, and the current volume of surgically treatable epilepsy is 1,819,067 cases across the region. Here, we review previously published epilepsy surgery programs in Africa, noting their outcomes.

METHODS

Eligible studies reporting seizure freedom and/or quality of life outcomes after epilepsy surgeries conducted in Africa were identified through database searches on PubMed/MEDLINE, Google Scholar, and reviewing references in previously identified publications.

RESULTS

While more than a thousand articles were retrieved in the database search, 17 full-length articles were reviewed for eligibility, and 8 articles (likely representing 7 unique patient cohorts) were ultimately included in this study. The reviewed studies demonstrated successful implementation of programs to evaluate patients with epilepsy for surgical treatment. About 60-100% of patients in these cohorts achieved good seizure freedom outcomes within a year from surgery and secondarily had improved quality of life and reduced severity of depression.

CONCLUSIONS

This review demonstrates that it is feasible to establish and sustain epilepsy surgery programs in Africa, with seizure freedom outcomes comparable to those reported in studies conducted in parts of the world with higher income.

Temporal Trends in Hippocampal Sclerosis Surgery: An Observational Study From a Tertiary Epilepsy Centre

OBJECTIVE

Temporal lobe epilepsy with hippocampal sclerosis (HS) is a surgically remediable syndrome. We determined temporal trends in the prevalence of hippocampal sclerosis surgeries and related factors.

METHODS

We analysed a prospective cohort of adults who underwent epilepsy surgery at the NHNN, London, between 1990 and 2019. HS group was compared with other pathologies. Demographics, surgical trends for HS and associations with sex, age, prior neurological insults and febrile seizures were analysed. Temporal trends were assessed by one-way or Welch ANOVA, with post hoc analysis. Surgery latency over three decades was evaluated with the Kruskal-Wallis H test, using Dunn's procedure for pairwise comparisons. Chi-squared analyses examined associations with sex, age at operation, febrile seizures, and between resection side and handedness.

RESULTS

Of 1069 people operated, 586 had hippocampal sclerosis. After increasing, surgeries declined in the last decade (from 322 to 131), as did the number of people with hippocampal sclerosis and a history of childhood febrile seizures (from 87 to 23). The median interval from epilepsy onset to surgery increased from 22 to 24 and 27 years over each decade. Female sex and febrile seizures were associated with pathology (HS vs. non-HS) but not age at surgery, previous neurological insults, or the resection side and handedness.

DISCUSSION

Our study confirms the decline in hippocampal surgeries. This trend may be due to changes in the syndrome's natural history, possibly from improved paediatric care, and an increase in complex cases. The impact of delayed referrals, surgical risk fears and newer anti-seizure medications remains unclear.

Intracerebral delivery of antiseizure medications by microinvasive neural implants

Focal epilepsy is a difficult disease to treat as two-thirds of patients will not respond to oral anti-seizure medications (ASMs) or have severe off-target effects that lead to drug discontinuation. Current non-pharmaceutical treatment methods (resection or ablation) are underutilized due to the associated morbidities, invasive nature and inaccessibility of seizure foci. Less invasive non-ablative modalities may potentially offer an alternative. Targeting the seizure focus in this way may avoid unassociated critical brain structures to preserve function and alleviate seizure burden. Here we report use of an implantable, miniaturized neural drug delivery system [microinvasive neural implant infusion platform (MINI)] to administer ASMs directly to the seizure focus in a mouse model of temporal lobe epilepsy. We examined the effect local delivery of phenobarbital and valproate had on focal seizures, as well as adverse effects, and compared this to systemic delivery. We show that local delivery of phenobarbital and valproate using our chronic implants significantly reduced focal seizures at all doses given. Furthermore, we show that local delivery of these compounds resulted in no adverse effects to motor function, whereas systemic delivery resulted in significant motor impairment. The results of this study demonstrate the potential of ASM micro dosing to the epileptic focus as a treatment option for people with drug resistant epilepsy. This technology could also be applied to a variety of disease states, enabling a deeper understanding of focal drug delivery in the treatment of neurological disorders.

Applications of magnetic resonance-guided laser interstitial thermal therapy in disconnective epilepsy surgery

Minimally invasive surgical techniques, such as MR-guided laser interstitial thermal therapy (LITT), have emerged as promising alternatives to open disconnective surgeries in drug-resistant epilepsy (DRE). This review synthesizes current literature on the application of LITT for corpus callosal disconnection and functional hemispheric disconnection. Studies highlight LITT's effectiveness for achieving seizure control and functional outcomes, often with reduced complications compared to traditional open procedures. Challenges include technical limitations to achieving total disconnection and adequate assessment of disconnection postoperatively. The literature is largely composed of observational studies and there is a need for rigorous, multi-center trials to establish robust guidelines and improve generalizability in clinical practice. There is also a need for a more robust exploration of how patient-specific factors contribute to response or nonresponse to intervention.

Expert opinion on use of vagus nerve stimulation therapy in the management of pediatric epilepsy: A Delphi consensus study

PURPOSE

To provide consensus-based recommendations for use of vagus nerve stimulation (VNS) therapy in the management of pediatric epilepsy.

METHODS

Delphi methodology with two rounds of online survey was used to build consensus. A steering committee developed 43 statements related to pediatric epilepsy and the use of VNS therapy, which were evaluated by a panel of 12 neurologists/neurosurgeons with expertise in pediatric epilepsy, who graded their agreement with each statement on a scale of 1 ("I do not agree at all") to 5 ("I strongly agree"). For each statement, consensus was established if ≥70% of the agreement scores were 4 or 5 and <30% were 1 or 2 in the final survey.

RESULTS

Twenty-four statements regarding the need for seizure reduction in pediatric epilepsy, the recommended treatment algorithm, the benefits and safety of VNS therapy, management of side effects of VNS therapy, patient selection for VNS therapy, and the use, dosing, and titration of VNS therapy achieved consensus. VNS and other neuromodulation therapies should be considered for pediatric patients with drug-resistant epilepsy who are not candidates for resective surgery, or who do not remain seizure free after resective surgery. When VNS therapy is initiated, the target dose range should be achieved via the fastest and safest titration schedule for each patient. Scheduled programming can be helpful in dose titration.

CONCLUSION

The expert consensus statements represent the panelists' collective opinion on the best practice use of VNS therapy to optimize outcomes in the management of pediatric epilepsy.

Differential electrographic seizure patterns in malformations of cortical development, early life brain injury, and later life brain injury

Structural epilepsy is a chronic neurologic condition that may be caused by in utero malformations of cortical development (MCD) or post-natal brain injuries resulting in encephalomalacia. We hypothesized that the timing of epileptogenic insult would lead to distinct electrographic seizure patterns. Specifically, we predicted that later life insults would lead to longer duration seizures with higher proportion of focal: focal to bilateral tonic-clonic (FBTC) seizures and low rates of bihemispheric onset seizures, as compared to early life insults. We performed a retrospective chart review of 70 adult patients - 33 with epilepsy secondary to brain injury (9 with injury occurring before 16 years and 24 with injury occurring at or after 16 years) with resultant encephalomalacia on MR imaging and 37 with epilepsy secondary to MCD - admitted to the University of Pittsburgh Epilepsy Monitoring Unit for presurgical evaluation. There were no significant differences in duration of epilepsy or number of trialed seizure medications between the groups. We examined scalp EEG data for all patients, as well as intracranial EEG data in a subset. We analyzed seizure duration, seizure frequency, and seizure type (focal, FBTC, and bihemispheric onset) in three cohorts: MCD patients, patients with brain injury occurring in early life (<16 years old), and patients with brain injury occurring in later life (≥16 years old). Patients with later life brain injury had significantly longer and less frequent seizures as compared to MCD cohorts. There were no differences between MCD and early life brain injury cohorts. Seizure duration findings were corroborated in a subset of patients who additionally underwent intracranial EEG monitoring. Additionally, later life brain injury patients had significantly different seizure types as compared to MCD cohorts, with high rates of FBTC and low rates of bihemispheric onset. Again, there was no significant differences in seizure type between early life brain injury and MCD cohorts. These novel findings indicate the relevance of timing of epileptogenic insult on the electrophysiological characteristics of structural epilepsies.

Evaluating the efficacy of transcranial direct current stimulation for refractory epilepsy: A meta-analysis of RCTs and non-RCTs

An increasing number of research indicate that non-invasive neurostimulation techniques, like transcranial direct current stimulation (tDCS), can effectively control refractory epilepsy. While previous meta-analyses have primarily focused on randomized controlled trials (RCTs), this study expands the scope by including both RCTs and non-RCTs to provide a more comprehensive assessment of tDCS efficacy in treating refractory epilepsy. Through a systematic search of "PUBMED, Embase and Cochrane", we sought relevant studies related to the research topic. We utilized the Cochrane Collaboration tool to assess the risk of bias for the RCTs and the Methodological Index for Non-Randomized Studies (MINORS) tool to evaluate the quality of the non-RCTs included in this meta-analysis. In addition, a protocol for this meta-analysis was registered on PROSPERO (CRD42024496837 http://www.crd.york.ac.uk/ PROSPERO). A total of 14 studies, including 8 RCTs and 6 non-RCTs , involving 307 subjects with refractory epilepsy, were included in this meta-analysis. The combined analysis of RCTs and non-RCTs indicated that tDCS was effective in reducing seizure frequency (SF) in refractory epilepsy patients, with significant improvements observed both four weeks (MD = -4.54; p ＜ 0.01; 95 % CI = -5.69 to -3.38) and eight weeks (MD = -3.49; p ＜ 0.01; 95 % CI = -5.37 to -1.61) after stimulation. There were no statistically significant differences in Interictal Epileptiform Discharges (IEDs) shortly after stimulation (MD = -3.59; p = 0.42; 95 % CI = -12.33-5.16). However, a reduction was observed at four weeks (MD = -5.28; p ＜ 0.01; 95 % CI = -6.88 to -3.68) and eight weeks post-stimulation (MD = -3.37; p ＜ 0.01; 95 % CI = -5.35 to -1.40). The patient's adverse reactions were mild, and they could be relieved shortly after discontinuation of the stimulus. The quality of evidence across outcomes was assessed as moderate. The results indicate that tDCS demonstrates promising efficacy and safety in managing seizures in refractory epilepsy. While this meta-analysis provides valuable findings, additional large-scale randomized controlled trials are needed to further confirm the efficacy of tDCS for refractory epilepsy.

Matrix-assisted laser desorption/ionization mass spectrometry imaging as a new tool for molecular histopathology in epilepsy surgery

OBJECTIVE

Epilepsy surgery is a treatment option for patients with seizures that do not respond to pharmacotherapy. The histopathological characterization of the resected tissue has an important prognostic value to define postoperative seizure outcome in these patients. However, the diagnostic classification process based on microscopic assessment remains challenging, particularly in the case of focal cortical dysplasia (FCD). Imaging mass spectrometry is a spatial omics technique that could improve tissue phenotyping and patient stratification by investigating hundreds of biomolecules within a single tissue sample, without the need for target-specific reagents.

METHODS

An in situ proteomic technique called matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is here investigated as a potential new tool to expand conventional diagnosis on standard paraffin brain tissue sections. Unsupervised and region of interest-based MALDI-MSI analyses of sections from 10 FCD type IIb (FCDIIb) cases were performed, and the results were validated by immunohistochemistry.

RESULTS

MALDI-MSI identified distinct histopathological features and the boundaries of the dysplastic lesion. The capability to visualize the spatial distribution of well-known diagnostic markers enabling multiplex measurements on single tissue sections was demonstrated. Finally, a fingerprint list of potential discriminant peptides that distinguish FCD core from peri-FCD tissue was generated.

SIGNIFICANCE

This is the first study that explores the potential application of MALDI-MSI in epilepsy postsurgery fixed tissue, by utilizing the well-characterized FCDIIb features as a model. Extending these preliminary analyses to a larger cohort of patients will generate spectral libraries of molecular signatures that discriminate tissue features and will contribute to patient phenotyping.

Research progress on the effects and mechanisms of magnetic field on neurodegenerative diseases

With the progress of modern science and technology, magnetic therapy technology develops rapidly, and many types of magnetic therapy methods continue to emerge, making magnetic therapy one of the main techniques of physiotherapy. With the continuous development of magnetic field research and clinical applications, magnetic therapy, as a non-invasive brain stimulation therapy technology, has attracted much attention due to its potential in the treatment of motor dysfunction, cognitive impairment and speech disorders in patients with neurodegenerative diseases. However, the role of magnetic fields in the prognosis and treatment of neurodegenerative diseases and their mechanisms remain largely unexplored. In this paper, the therapeutic effect and neuroprotective mechanism of the magnetic field on neurodegenerative diseases are reviewed, and the new magnetic therapy techniques are also summarized. Although the neuroprotective mechanism of magnetic field cannot be fully elaborated, it is helpful to promote the application of magnetic field in neurodegenerative diseases and provide a new theoretical basis for the related magnetic field research in the later period.

Do germline genetic variants influence surgical outcomes in drug-resistant epilepsy?

OBJECTIVE

We retrospectively explored patients with drug-resistant epilepsy (DRE) who previously underwent presurgical evaluation to identify correlations between surgical outcomes and pathogenic variants in epilepsy genes.

METHODS

Through an international collaboration, we evaluated adult DRE patients who were screened for surgical candidacy. Patients with pathogenic (P) or likely pathogenic (LP) germline variants in genes relevant to their epilepsy were included, regardless of whether the genetic diagnosis was made before or after the presurgical evaluation. Patients were divided into two groups: resective surgery (RS) and non-resective surgery candidates (NRSC), with the latter group further divided into: palliative surgery (vagus nerve stimulation, deep brain stimulation, responsive neurostimulation or corpus callosotomy) and no surgery. We compared surgical candidacy evaluations and postsurgical outcomes in patients with different genetic abnormalities.

RESULTS

We identified 142 patients with P/LP variants. After presurgical evaluation, 36 patients underwent RS, while 106 patients were NRSC. Patients with variants in ion channel and synaptic transmission genes were more common in the NRSC group (48 %), compared with the RS group (14 %) (p<0.001). Most patients in the RS group had tuberous sclerosis complex. Almost half (17/36, 47 %) in the RS group had Engel class I or II outcomes. Patients with channelopathies were less likely to undergo a surgical procedure than patients with mTORopathies, but when deemed suitable for resection had better surgical outcomes (71 % versus 41 % with Engel I/II). Within the NRSC group, 40 underwent palliative surgery, with 26/40 (65 %) having ≥50 % seizure reduction after mean follow-up of 11 years. Favourable palliative surgery outcomes were observed across a diverse range of genetic epilepsies.

SIGNIFICANCE

Genomic findings, including a channelopathy diagnosis, should not preclude presurgical evaluation or epilepsy surgery, and appropriately selected cases may have good surgical outcomes. Prospective registries of patients with monogenic epilepsies who undergo epilepsy surgery can provide additional insights on outcomes.

Cenobamate: real-world data from a retrospective multicenter study

BACKGROUND

Clinical trials have shown that cenobamate (CNB) is an efficacious and safe anti-seizure medication (ASM) for drug-resistant focal epilepsy. Here, we analyzed one of the largest real-world cohorts, covering the entire spectrum of epilepsy syndromes, the efficacy and safety of CNB, and resulting changes in concomitant ASMs.

METHODS

We conducted a retrospective observational study investigating CNB usage in two German tertiary referral centers between October 2020 and June 2023 with follow-up data up to 27 months of treatment. Our primary outcome was treatment response. Secondary outcomes comprised drug response after 12 and 18 months, seizure freedom rates, CNB dosage and retention, adverse drug reactions (ADRs), and changes in concomitant ASMs.

RESULTS

116 patients received CNB for at least two weeks. At 6 months, 98 patients were eligible for evaluation. Thereof 50% (49/98) were responders with no relevant change at 12 and 18 months. Seizure freedom was achieved in 18.4% (18/98) at 6 months, 16.7% (11/66), and 3.0% (1/33) at 12 and 18 months. The number of previous ASMs did not affect the seizure response rate. Overall, CNB was well-tolerated, however, in 7.7% (9/116), ADRs led to treatment discontinuation. The most frequent changes of concomitant ASMs included the discontinuation or reduction of sodium channel inhibitors, clobazam reduction, and perampanel discontinuation, while brivaracetam doses were usually left unchanged.

CONCLUSIONS

CNB proved to be a highly effective and generally well-tolerated ASM in patients with severe drug-resistant epilepsy, comprising a broad array of epilepsy syndromes beyond focal epilepsy.

Ultrasound-Navigated Multiple Hippocampal Transections: An Anatomical Study

BACKGROUND

 Multiple hippocampal transection (MHT) is a surgical technique used for the treatment of drug-resistant mesial temporal lobe epilepsy in situations where standard procedures would pose a high risk for memory deterioration. During MHT, the longitudinal fibers of the hippocampus, implicated in epilepsy spreading, are interrupted, while the transverse memory circuits are spared. The extent of MHT is governed by intraoperative electrocorticography; abolition of epileptic discharges serves as an end point to terminate the transection. In other words, the aim of MHT is not the anatomical completeness of hippocampal transection. In contrast, we hypothesize that only the complete transection of hippocampal cross-section is needed to durably terminate epilepsy, avoiding possible postoperative reorganization of longitudinal pathways. Here, we report an anatomical study designed to evaluate the feasibility of complete transection of hippocampus with the aid of ultrasound neuronavigation and we propose new instruments to reach this goal.

METHODS

 Five cadaveric brains were analyzed in this study. MHT was performed on both sides of each brain either with or without ultrasound neuronavigation. The percentage of transected cross-section of the hippocampus was measured using magnetic resonance imaging (MRI) and both sides were compared.

RESULTS

 The ultrasound-guided MHTs were more likely to achieve complete hippocampal transection compared with the nonnavigated MHT transection (73 vs 58%; p < 0.01). Our study also allowed us to propose specialized transectors to minimize invasivity of this procedure.

CONCLUSION

 Completeness of MHT can be better reached with the aid of an ultrasound neuronavigation system; modified instruments for this procedure were also designed.

Review: seizure-related consolidation and the network theory of epilepsy

Epilepsy is a complex, multifaceted disease that affects patients in several ways in addition to seizures, including psychological, social, and quality of life issues, but epilepsy is also known to interact with sleep. Seizures often occur at the boundary between sleep and wake, patients with epilepsy often experience disrupted sleep, and the rate of inter-ictal epileptiform discharges increases during non-REM sleep. The Network Theory of Epilepsy did not address a role for sleep, but recent emphasis on the interaction between epilepsy and sleep suggests that post-seizure sleep may also be involved in the process by which seizures arise and become more severe with time ("epileptogenesis") by co-opting processes related to the formation of long-term memories. While it is generally acknowledged that recurrent seizures arise from the aberrant function of neural circuits, it is possible that the progression of epilepsy is aided by normal, physiological function of neural circuits during sleep that are driven by pathological signals. Studies recording multiple, single neurons prior to spontaneous seizures have shown that neural assemblies activated prior to the start of seizures were reactivated during post-seizure sleep, similar to the reactivation of behavioral neural assemblies, which is thought to be involved in the formation of long-term memories, a process known as Memory Consolidation. The reactivation of seizure-related neural assemblies during sleep was thus described as being a component of Seizure-Related Consolidation (SRC). These results further suggest that SRC may viewed as a network-related aspect of epilepsy, even in those seizures that have anatomically restricted neuroanatomical origins. As suggested by the Network Theory of Epilepsy as a means of interfering with ictogenesis, therapies that interfered with SRC may provide some anti-epileptogenic therapeutic benefit, even if the interference targeted structures that were not involved originally in the seizure. Here, we show how the Network Theory of Epilepsy can be expanded to include neural plasticity mechanisms associated with learning by providing an overview of Memory Consolidation, the mechanisms thought to underlie MC, their relation to Seizure-Related Consolidation, and suggesting novel, anti-epileptogenic therapies targeting interference with network activation in epilepsy following seizures during post-seizure sleep.

Current role of magnetic resonance imaging on assessing and monitoring the efficacy of phototherapy

Phototherapy, also known as photobiological therapy, is a non-invasive and highly effective physical treatment method. Its broad use in clinics has led to significant therapeutic results. Phototherapy parameters, such as intensity, wavelength, and duration, can be adjusted to create specific therapeutic effects for various medical conditions. Meanwhile, Magnetic Resonance Imaging (MRI), with its diverse imaging sequences and excellent soft-tissue contrast, provides a valuable tool to understand the therapeutic effects and mechanisms of phototherapy. This review explores the clinical applications of commonly used phototherapy techniques, gives a brief overview of how phototherapy impacts different diseases, and examines MRI's role in various phototherapeutic scenarios. We argue that MRI is crucial for precise targeting, treatment monitoring, and prognosis assessment in phototherapy. Future research and applications will focus on personalized diagnosis and monitoring of phototherapy, expanding its applications in treatment and exploring multimodal imaging technology to enhance diagnostic and therapeutic precision and effectiveness.

Exploring the content of epilepsy fellowship program websites: an analysis of information available to applicants

BACKGROUND

Program websites are essential resources in the process of residency and fellowship application. We evaluated the information furnished on these resources by Epilepsy fellowship programs. The extent of information provided was compared across geographic zones, academic affiliation, and national ranking.

METHODS

A list of Epilepsy fellowship programs was derived from the Fellowship and Residency Electronic Interactive Database (FREIDA). Links to program websites were obtained directly from FREIDA or using Google's search engine. Online data was categorized to reflect program information, education, recruitment, compensation, epilepsy center-specific information, and social media presence. Data points under each category were collected to develop a standardized scoring system. The frequency of criterion present was compared across geographic zones, academic affiliation, and national ranking using parametric and non-parametric statistical tests. Significance was determined at a p-value ≤ 0.05 for all cases. The study utilized IBM SPSS version 28 and Python 3.11.3.

RESULTS

We analyzed 80 Epilepsy fellowship programs. The most reported feature was the program director's name and email (100.0%). The least reported features included board pass rates (1.3%), preparatory boot camp (8.8%), and post-fellowship placements (11.3%). Programs were found to be well-represented on X (88.8%), Facebook (81.3%), and Instagram (71.3%). Most (85.0%) of the programs were searchable through Google. The scores for program information, education, recruitment, compensation, epilepsy center-specific information, and social media visibility did not significantly vary based on location, academic affiliation, or rank status.

CONCLUSIONS

Our results demonstrate that despite an online presence, there is much room for improvement in the content available to the applicant. To improve the Match process and attract a roster of well-informed fellows, Epilepsy fellowship programs should furnish program websites with up-to-date information relevant to program information, education, recruitment, compensation, and epilepsy center-specific information.

New Pharmacological Therapies in the Treatment of Epilepsy in the Pediatric Population

Epilepsy is a disorder characterized by abnormal brain neuron activity, predisposing individuals to seizures. The International League Against Epilepsy (ILAE) categorizes epilepsy into the following groups: focal, generalized, generalized and focal, and unknown. Infants are the most vulnerable pediatric group to the condition, with the cause of epilepsy development being attributed to congenital brain developmental defects, white matter damage, intraventricular hemorrhage, perinatal hypoxic-ischemic injury, perinatal stroke, or genetic factors such as mutations in the Sodium Channel Protein Type 1 Subunit Alpha (SCN1A) gene. Due to the risks associated with this condition, we have investigated how the latest pharmacological treatments for epilepsy in children impact the reduction or complete elimination of seizures. We reviewed literature from 2018 to 2024, focusing on the age group from 1 month to 18 years old, with some studies including this age group as well as older individuals. The significance of this review is to present and compile research findings on the latest antiseizure drugs (ASDs), their effectiveness, dosing, and adverse effects in the pediatric population, which can contribute to selecting the best drug for a particular patient. The medications described in this review have shown significant efficacy and safety in the studied patient group, outweighing the observed adverse effects. The main aim of this review is to provide a comprehensive summary of the current state of knowledge regarding the newest pharmacotherapy for childhood epilepsy.

[Neuropsychological profile of Mexican paediatric patients with pharmacoresistant focal epilepsy]

INTRODUCTION

At least 20% of paediatric patients with epilepsy present resistance to multiple anti-crisis drugs in trials, which has a negative impact on their neuropsychological state, quality of life and prognosis; it is therefore necessary to document their neuropsychological profile in order to improve the clinical approach to them.

AIMS

To describe the neuropsychological profile (cognitive, academic, behavioural, emotional, adaptive, sleep disturbances and quality of life) of paediatric patients with drug-resistant focal epilepsy in the frontal, temporal and occipital lobes, and to compare performance between patients with frontal and temporal foci, and to assess the link between the duration of the condition, the frequency of seizures and the amount of anti-crisis drugs and the neuropsychological profile.

PATIENTS AND METHODS

The neuropsychological profile of 19 paediatric patients with a diagnosis of pharmacoresistant epilepsy with a mean age of 10.89 years was evaluated.

RESULTS

57.9% of the 19 patients were men. 63.2% presented frontal focus; 26.3% presented temporal focus; and 10.5% presented occipital focus. Deficiencies in attention, comprehension, verbal memory, working memory and processing speed, in addition to adaptive difficulties were observed. When the patients with frontal and temporal focus were compared, the former were found to present greater deficits in planning, while the patients with temporal focus presented more severe symptoms of anxiety. Patients with a longer disease duration were found to present greater impairment to their intelligence quotient and adaptive behavioural skills.

CONCLUSIONS

Pharmacoresistant epilepsy in paediatric patients affects intelligence quotient and adaptive skills, as well as attention, memory and executive functions, and neuropsychological intervention programmes must therefore be implemented to improve these patients' quality of life.

Outcome of emergency neurosurgery in patients with refractory and super-refractory status epilepticus: a systematic review and individual participant data meta-analysis

Background

Refractory (RSE) and super-refractory status epilepticus (SRSE) are serious neurological conditions requiring aggressive management. Beyond anesthetic agents, there is a lack of evidence guiding management in these patients. This systematic review and individual participant data meta-analysis (IPDMA) seeks to evaluate and compare the currently available surgical techniques for the acute treatment of RSE and SRSE.

Methods

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Individual Participant Data (PRISMA-IPD). Only patients who underwent surgery while in RSE and SRSE were included. Descriptive statistics were used to compare various subgroups. Multivariable logistic regression models were constructed to identify predictors of status epilepticus (SE) cessation, long-term overall seizure freedom, and favorable functional outcome (i.e., modified Rankin score of 0-2) at last follow-up.

Results

A total of 87 studies including 161 participants were included. Resective surgery tended to achieve better SE cessation rate (93.9%) compared to non-resective techniques (83.9%), but this did not reach significance (p = 0.071). Resective techniques were also more likely to achieve seizure freedom (69.1% vs. 34.4%, p = <0.0001). Older age at SE (OR = 1.384[1.046-1.832], p = 0.023) was associated with increased likelihood of SE cessation, while longer duration of SE (OR = 0.603[0.362-1.003], p = 0.051) and new-onset seizures (OR = 0.244[0.069-0.860], p = 0.028) were associated with lower likelihood of SE cessation, but this did not reach significance for SE duration. Only shorter duration of SE prior to surgery (OR = 1.675[1.168-2.404], p  = 0.0060) and immediate termination of SE (OR = 3.736 [1.323-10.548], p = 0.014) were independently associated with long-term seizure status. Rates of favorable functional outcomes (mRS of 0-2) were comparable between resective (44.4%) and non-resective (44.1%) techniques, and no independent predictors of outcome were identified.

Conclusion

Our findings suggest that emergency neurosurgery may be a safe and effective alternative in patients with RSE/SRSE and may be considered earlier during the disease course. However, the current literature is limited exclusively to small case series and case reports with high risk of publication bias. Larger clinical trials assessing long-term seizure and functional outcomes are warranted to establish robust management guidelines.

High-Value Epilepsy Care in the United States: Predictors of Increased Costs and Complications from the National Inpatient Sample Database 2016-2019

BACKGROUND

For patients with medically refractory epilepsy, newer minimally invasive techniques such as laser interstitial thermal therapy (LITT) have been developed in recent years. This study aims to characterize trends in the utilization of surgical resection versus LITT to treat medically refractory epilepsy, characterize complications, and understand the cost of this innovative technique to the public.

METHODS

The National Inpatient Sample database was queried from 2016 to 2019 for all patients admitted with a diagnosis of medically refractory epilepsy. Patient demographics, hospital length of stay, complications, and costs were tabulated for all patients who underwent LITT or surgical resection within these cohorts.

RESULTS

A total of 6019 patients were included, 223 underwent LITT procedures, while 5796 underwent resection. Significant predictors of increased patient charges for both cohorts included diabetes (odds ratio: 1.7, confidence interval [CI]: 1.44-2.19), infection (odds ratio: 5.12, CI 2.73-9.58), and hemorrhage (odds ratio: 2.95, CI 2.04-4.12). Procedures performed at nonteaching hospitals had 1.54 greater odds (CI 1.02-2.33) of resulting in a complication compared to teaching hospitals. Insurance status did significantly differ (P = 0.001) between those receiving LITT (23.3% Medicare; 25.6% Medicaid; 44.4% private insurance; 6.7 Other) and those undergoing resection (35.3% Medicare; 22.5% Medicaid; 34.7% private Insurance; 7.5% other). When adjusting for patient demographics, LITT patients had shorter length of stay (2.3 vs. 8.9 days, P < 0.001), lower complication rate (1.9% vs. 3.1%, P = 0.385), and lower mean hospital ($139,412.79 vs. $233,120.99, P < 0.001) and patient ($55,394.34 vs. $37,756.66, P < 0.001) costs.

CONCLUSIONS

The present study highlights LITT's advantages through its association with lower costs and shorter length of stay. The present study also highlights the associated predictors of LITT versus resection, such as that most LITT cases happen at academic centers for patients with private insurance. As the adoption of LITT continues, more data will become available to further understand these issues.

Canadian Practice and Recommendations on Functional MRI to Lateralize Language in Epilepsy

BACKGROUND/OBJECTIVE

Identifying a patient's dominant language hemisphere is an important evaluation performed prior to epilepsy surgery and is commonly assessed using functional magnetic resonance imaging (fMRI). However, the lack of standardization and resultant heterogeneity of fMRI paradigms used in clinical practice limits the ability of cross-center comparisons to be made regarding language laterality results.

METHODS

Through surveying Canadian Epilepsy Centres in combination with reviewing supporting literature, current fMRI language lateralization practices for the clinical evaluation of patients with epilepsy were assessed. To encourage standardization of this practice, we outlined a two-part paradigm series that demonstrates widespread acceptance, reliability and accessibility in lateralizing various aspects of language functioning in individuals with average or near-average IQ and normal literacy skills.

RESULTS

The collected data confirm a lack of standardization in fMRI laterality assessments leading to clinical heterogeneity in stimulation and control tasks, paradigm design and timing, laterality index calculations, thresholding values and analysis software and technique. We suggest a Sentence Completion (SC) and Word Generation (WG) paradigm series as it was most commonly employed across Canada, demonstrated reliability in lateralizing both receptive and expressive language areas in supporting literature, and could be readily intelligible to an inclusive population.

CONCLUSION

Through providing recommendations for a two-part paradigm series, we hope to contribute to the standardization of this practice across Canada to reduce clinical heterogeneity, encourage communicability between institutions, and enhance methodologies for the surgical treatment of epilepsy for the benefit of all individuals living with epilepsy in Canada.

Pediatric neuromodulation for drug-resistant epilepsy: Survey of current practices, techniques, and outcomes across US epilepsy centers

Neuromodulation via Responsive Neurostimulation (RNS) or Deep Brain Stimulation (DBS) is an emerging treatment strategy for pediatric drug-resistant epilepsy (DRE). Knowledge gaps exist in patient selection, surgical technique, and perioperative care. Here, we use an expert survey to clarify practices. Thirty-two members of the Pediatric Epilepsy Research Consortium were surveyed using REDCap. Respondents were from 17 pediatric epilepsy centers (missing data in one): Four centers implant RNS only while 13 implant both RNS and DBS. Thirteen RNS programs commenced in or before 2020, and 10 of 12 DBS programs began thereafter. The busiest six centers implant 6-10 new RNS devices per year; all DBS programs implant <5 annually. The youngest RNS patient was 3 years old. Most centers (11/12) utilize MP2RAGE and/or FGATIR sequences for planning. Centromedian thalamic nuclei were the unanimous target for Lennox-Gastaut syndrome. Surgeon exposure to neuromodulation occurred mostly in clinical practice (14/17). Clinically significant hemorrhage (n = 2) or infection (n = 3) were rare. Meaningful seizure reduction (>50%) was reported by 81% (13/16) of centers. RNS and DBS are rapidly evolving treatment modalities for safe and effective treatment of pediatric DRE. There is increasing interest in multicenter collaboration to gain knowledge and facilitate dialogue. PLAIN LANGUAGE SUMMARY: We surveyed 32 pediatric epilepsy centers in USA to highlight current practices of intracranial neuromodulation. Of the 17 that replied, we found that most centers are implanting thalamic targets in pediatric drug-resistant epilepsy using the RNS device. DBS device is starting to be used in pediatric epilepsy, especially after 2020. Different strategies for target identification are enumerated. This study serves as a starting point for future collaborative research.

From Alzheimer's Disease to Anxiety, Epilepsy to Schizophrenia: A Comprehensive Dive Into Neuro-Psychiatric Disorders

This comprehensive narrative review endeavors to dissect the intricate web of neuropsychiatric disorders that significantly impact cognition, emotion regulation, behavior, and mental health. With a keen focus on Alzheimer's disease (AD), anxiety disorders, epilepsy, schizophrenia, and autism spectrum disorder (ASD), this article delves into their underlying mechanisms, clinical presentations, diagnostic challenges, and therapeutic interventions. Highlighting the considerable disability and societal costs that these conditions impose, it reflects on the over six million individuals grappling with Alzheimer's, the 19 million American adults living with anxiety disorders, the three million with epilepsy, and the global reach of schizophrenia affecting approximately 20 million people. Furthermore, it examines the emerging landscape of ASD, noting the escalating diagnosis rates and the pressing need for innovative treatments and equitable healthcare access. Through a detailed exploration of current research, technological innovations, and the promise of personalized medicine, this review aims to illuminate the complexities of these conditions, advocate for early intervention strategies, and call for a unified approach to tackling the multifaceted challenges they present. The ultimate goal is to inform and inspire healthcare professionals, researchers, and policymakers to foster advancements that improve outcomes and quality of life for individuals affected by these profound neuropsychiatric disorders, steering towards a future where these conditions are no longer insurmountable.

Low-frequency stimulation in the zona incerta attenuates seizure via driving GABAergic neuronal activity

BACKGROUND

Managing refractory epilepsy presents a significant a substantial clinical challenge. Deep brain stimulation (DBS) has emerged as a promising avenue for addressing refractory epilepsy. However, the optimal stimulation targets and effective parameters of DBS to reduce seizures remian unidentified.

OBJECTIVES

This study endeavors to scrutinize the therapeutic potential of DBS within the zona incerta (ZI) across diverse seizure models and elucidate the associated underlying mechanisms.

METHODS

We evaluated the therapeutic potential of DBS with different frequencies in the ZI on kainic acid (KA)-induced TLE model or M1-cortical seizures model, pilocarpine-induced M1-cortical seizure models, and KA-induced epilepsy model. Further, employing calcium fiber photometry combined with cell-specific ablation, we sought to clarified the causal role of ZI GABAergic neurons in mediating the therapeutic effects of DBS.

RESULTS

Our findings reveal that DBS in the ZI alleviated the severity of seizure activities in the KA-induced TLE model. Meanwhile, DBS attenuated seizure activities in KA- or pilocarpine-induced M1-cortical seizure model. In addition, DBS exerts a mitigating influence on KA induced epilepsy model. DBS in the ZI showed anti-seizure effects at low frequency spectrum, with 5 Hz exhibiting optimal efficacy. The low-frequency DBS significantly increased the calcium activities of ZI GABAergic neurons. Furthermore, selective ablation of ZI GABAergic neurons with taCasp3 blocked the anti-seizure effect of low-frequency DBS, indicating the anti-seizure effect of DBS is mediated by the activation of ZI GABAergic neurons.

CONCLUSION

Our results demonstrate that low-frequency DBS in the ZI attenuates seizure via driving GABAergic neuronal activity. This suggests that the ZI represents a potential DBS target for treating both hippocampal and cortical seizure through the activation of GABAergic neurons, thereby holding therapeutic significance for seizure treatment.

Is intraoperative electrocorticography (ECoG) for long-term epilepsy-associated tumors (LEATs) more useful in children?-A Randomized Controlled Trial

OBJECTIVES

The utility of intraoperative electrocorticography (ECoG)-guided resective surgery for pediatric long-term epilepsy-associated tumors (LEATs) with antiseizure medication (ASM) resistant epilepsy is not supported by robust evidence. As epilepsy networks and their ramifications are different in children from those in adults, the impact of intraoperative ECoG-based tailored resections in predicting prognosis and influencing outcomes may also differ. We evaluated this hypothesis by comparing the outcomes of resections with and without the use of ECoG in children and adults by a randomized study.

METHODS

From June 2020 to January 2022, 42 patients (17 children and 25 adults) with LEATs and antiseizure medication (ASM)-resistant epilepsy were randomly assigned to one of the 2 groups (ECoG or no ECoG), prior to surgical resection. The 'no ECoG' arm underwent gross total lesion resection (GTR) without ECoG guidance and the ECoG arm underwent GTR with ECoG guidance and further additional tailored resections, as necessary. Factors evaluated were tumor location, size, lateralization, seizure duration, preoperative antiepileptic drug therapy, pre- and postresection ECoG patterns and tumor histology. Postoperative Engel score and adverse event rates were compared in the pediatric and adult groups of both arms. Eloquent cortex lesions and re-explorations were excluded to avoid confounders.

RESULTS

Forty-two patients were included in the study of which 17 patients were in the pediatric cohort (age < 18 years) and 25 in the adult cohort. The mean age in the pediatric group was 11.11 years (SD 4.72) and in the adult group was 29.56 years (SD 9.29). The mean duration of epilepsy was 9.7 years (SD 4.8) in the pediatric group and 10.96 (SD 8.8) in the adult group. The ECoG arm of LEAT resections had 23 patients (9 children and 14 adults) and the non-ECoG arm had 19 patients (8 children and 11 adults). Three children and 3 adults from the ECoG group further underwent ECoG-guided tailored resections (average 1.33 additional tailored resections/per patient.).The histology of the tailored resection specimen was unremarkable in 3/6 (50%).Overall, the commonest histology in both groups was ganglioglioma and the temporal lobe, the commonest site of the lesion. 88.23% of pediatric cases (n = 15/17) had an excellent outcome (Engel Ia) following resection, compared to 84% of adult cases (n = 21/25) at a mean duration of follow-up of 25.76 months in children and 26.72 months in adults (p = 0.405).There was no significant difference in seizure outcomes between the ECoG and no ECoG groups both in children and adults, respectively (p > 0.05). Additional tailored resection did not offer any seizure outcome benefit when compared to the non-tailored resections.

CONCLUSIONS

The use of intraoperative electrocorticography in LEATs did not contribute to postoperative seizure outcome benefit in children and adults. No additional advantage or utility was offered by ECoG in children when compared to its use in adults. ECoG-guided additional tailored resections did not offer any additional seizure outcome benefit both in children and adults.

Measuring quality and safety of epilepsy monitoring units in Brazil: Adoption of quality indicators

PURPOSE

Drug-resistant epilepsy affects a substantial proportion (30-40 %) of patients with epilepsy, often necessitating video-electroencephalography (video-EEG) monitoring. In 2016, Sauro et al. introduced a set of measures aimed at improving the quality and safety indicators reported in video-EEG evaluations. This study aims to report our experience with the implementation of these measures.

METHODS

We analyzed video-EEG data regarding quality and safty from a period spanning January 2016 to January 2018, involving a total of 101 patients monitored in our video-EEG unit.

RESULTS

Among the patients included in the study, a definitive diagnosis was attainable for 92.1 %, with 36.6 % experiencing a change in diagnosis and 65.3 % undergoing a change in treatment as a result of the video-EEG evaluation. Additionally, the referral question was fully addressed in 60.4 % of admissions, and video-EEG was considered to be very useful or extremely useful in 66.4 % of cases. Adverse events were observed in 26.7 % of patients, with the most common being the progression of focal seizures to bilateral tonic-clonic seizures (11.9 %) and the occurrence of seizure clusters (5.9 %).

CONCLUSION

Our findings support the implementation of Sauro et al.'s set of measures, as they provide valuable criteria for improving the reporting of video-EEG quality and safety indicators. However, challenges may arise due to variations in terminology across studies and the lack of standardized criteria for defining essential questions in video-EEG evaluations. Further research utilizing these measures is necessary to enhance their effectiveness and encourage consistent reporting of results from epilepsy monitoring units.

Role of machine learning in the management of epilepsy: a systematic review protocol

INTRODUCTION

Machine learning is a rapidly expanding field and is already incorporated into many aspects of medicine including diagnostics, prognostication and clinical decision-support tools. Epilepsy is a common and disabling neurological disorder, however, management remains challenging in many cases, despite expanding therapeutic options. We present a systematic review protocol to explore the role of machine learning in the management of epilepsy.

METHODS AND ANALYSIS

This protocol has been drafted with reference to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) for Protocols. A literature search will be conducted in databases including MEDLINE, Embase, Scopus and Web of Science. A PRISMA flow chart will be constructed to summarise the study workflow. As the scope of this review is the clinical application of machine learning, the selection of papers will be focused on studies directly related to clinical decision-making in management of epilepsy, specifically the prediction of response to antiseizure medications, development of drug-resistant epilepsy, and epilepsy surgery and neuromodulation outcomes. Data will be extracted following the CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies checklist. Prediction model Risk Of Bias ASsessment Tool will be used for the quality assessment of the included studies. Syntheses of quantitative data will be presented in narrative format.

ETHICS AND DISSEMINATION

As this study is a systematic review which does not involve patients or animals, ethics approval is not required. The results of the systematic review will be submitted to peer-review journals for publication and presented in academic conferences.

PROSPERO REGISTRATION NUMBER

CRD42023442156.

Digital Therapeutics for Improving Effectiveness of Pharmaceutical Drugs and Biological Products: Preclinical and Clinical Studies Supporting Development of Drug + Digital Combination Therapies for Chronic Diseases

Limitations of pharmaceutical drugs and biologics for chronic diseases (e.g., medication non-adherence, adverse effects, toxicity, or inadequate efficacy) can be mitigated by mobile medical apps, known as digital therapeutics (DTx). Authorization of adjunct DTx by the US Food and Drug Administration and draft guidelines on "prescription drug use-related software" illustrate opportunities to create drug + digital combination therapies, ultimately leading towards drug-device combination products (DTx has a status of medical devices). Digital interventions (mobile, web-based, virtual reality, and video game applications) demonstrate clinically meaningful benefits for people living with Alzheimer's disease, dementia, rheumatoid arthritis, cancer, chronic pain, epilepsy, depression, and anxiety. In the respective animal disease models, preclinical studies on environmental enrichment and other non-pharmacological modalities (physical activity, social interactions, learning, and music) as surrogates for DTx "active ingredients" also show improved outcomes. In this narrative review, we discuss how drug + digital combination therapies can impact translational research, drug discovery and development, generic drug repurposing, and gene therapies. Market-driven incentives to create drug-device combination products are illustrated by Humira® (adalimumab) facing a "patent-cliff" competition with cheaper and more effective biosimilars seamlessly integrated with DTx. In conclusion, pharma and biotech companies, patients, and healthcare professionals will benefit from accelerating integration of digital interventions with pharmacotherapies.

The efficacy and safety of third-generation antiseizure medications and non-invasive brain stimulation to treat refractory epilepsy: a systematic review and network meta-analysis study

Background

The new antiseizure medications (ASMs) and non-invasive brain stimulation (NIBS) are controversial in controlling seizures. So, this network meta-analysis aimed to evaluate the efficacy and safety of five third-generation ASMs and two NIBS therapies for the treatment of refractory epilepsy.

Methods

We searched PubMed, EMBASE, Cochrane Library and Web of Science databases. Brivaracetam (BRV), cenobamate (CNB), eslicarbazepine acetate (ESL), lacosamide (LCM), perampanel (PER), repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS) were selected as additional treatments for refractory epilepsy in randomized controlled studies and other cohort studies. Randomized, double-blind, placebo-controlled, add-on studies that evaluated the efficacy or safety of medication and non-invasive brain stimulation and included patients with seizures were uncontrolled by one or more concomitant ASMs were identified. A random effects model was used to incorporate possible heterogeneity. The primary outcome was the change in seizure frequency from baseline, and secondary outcomes included the proportion of patients with ≥50% reduction in seizure frequency, and the rate of treatment-emergent adverse events.

Results

Forty-five studies were analyzed. The five ASMs and two NIBS decreased seizure frequency from baseline compared with placebo. The 50% responder rates of the five antiseizure drugs were significantly higher than that of placebo, and the ASMs were associated with fewer adverse events than placebo (p < 0.05). The surface under the cumulative ranking analysis revealed that ESL was most effective in decreasing the seizure frequency from baseline, whereas CNB provided the best 50% responder rate. BRV was the best tolerated. No significant publication bias was identified for each outcome index.

Conclusion

The five third-generation ASMs were more effective in controlling seizures than placebo, among which CNB, ESL, and LCM were most effective, and BRV exhibited better safety. Although rTMS and tDCS did not reduce seizure frequency as effectively as the five drugs, their safety was confirmed.

Systematic review registration

PROSPERO, https://www.crd.york.ac.uk/prospero/ (CRD42023441097).

Trends in the Utilization of Surgical Modalities for the Treatment of Drug-Resistant Epilepsy: A Comprehensive 10-Year Analysis Using the National Inpatient Sample

BACKGROUND AND OBJECTIVES

Epilepsy is considered one of the most prevalent and severe chronic neurological disorders worldwide. Our study aims to analyze the national trends in different treatment modalities for individuals with drug-resistant epilepsy and investigate the outcomes associated with these procedural trends in the United States.

METHODS

Using the National Inpatient Sample database from 2010 to 2020, patients with drug-resistant focal epilepsy who underwent laser interstitial thermal therapy (LITT), open surgical resection, vagus nerve stimulation (VNS), or responsive neurostimulation (RNS) were identified. Trend analysis was performed using piecewise joinpoint regression. Propensity score matching was used to compare outcomes between 10 years prepandemic before 2020 and the first peak of the COVID-19 pandemic.

RESULTS

This study analyzed a total of 33 969 patients with a diagnosis of drug-resistant epilepsy, with 3343 patients receiving surgical resection (78%), VNS (8.21%), RNS (8%), and LITT (6%). Between 2010 and 2020, there was an increase in the use of invasive electroencephalography monitoring for seizure zone localization (P = .003). There was an increase in the use of LITT and RNS (P < .001), while the use of surgical resection and VNS decreased over time (P < .001). Most of these patients (89%) were treated during the pre-COVID pandemic era (2010-2019), while a minority (11%) underwent treatment during the COVID pandemic (2020). After propensity score matching, the rate of pulmonary complications, postprocedural hematoma formation, and mortality were slightly higher during the pandemic compared with the prepandemic period (P = .045, P = .033, and P = .026, respectively).

CONCLUSION

This study indicates a relative decrease in the use of surgical resections, as a treatment for drug-resistant focal epilepsy. By contrast, newer, minimally invasive surgical approaches including LITT and RNS showed gradual increases in usage.

Individuals' invisible work continues after epilepsy surgery: A qualitative interview study

OBJECTIVE

How do persons with epilepsy (PWE) experience their everyday lives after epilepsy surgery?

METHODS

Qualitative thematic interviews were conducted with eight PWEs (30 to 60 years old). They were recruited when coming for post-operative control 1 to 5 years after epilepsy surgery. The interviews were transcribed. They were analysed by thematic analysis and inspired by Goffman who examines everyday life activities as a theatre play.

RESULTS

Before surgery, a substantial invisible and hidden work of adjustments was performed to prevent seizures, to secure help from others if seizures occurred, and to protect oneself from others' gaze during a seizure. This invisible work continued after surgery even for those who became seizure-free; but now for the purpose of protecting oneself from relapse of epilepsy. From the participants perspective there was no or minor change in daily activities among those not becoming seizure-free after surgery. In contrast, those who became seizure-free enjoyed the freedom to participate in social activities without planning or restrictions.

CONCLUSIONS

A striking finding was that daily life after surgery comprises considerably invisible work to protect a social self, and this preventive and protective invisible work continued, although those who became seizure-free were living an ordinary socially healthy life.

Long-term seizure and developmental outcomes of epilepsy surgery in children under 3 years old: A single-center study of 113 patients

AIMS

To investigate the clinical characteristics, surgical strategy, developmental and seizure outcomes, and predictors of surgical outcome in children with drug-resistant epilepsy (DRE) under 3 years old.

METHODS

One hundred thirteen consecutive children younger than 3 years of age with DRE underwent curative surgical treatment after multidisciplinary preoperative evaluation using the strategy developed in the pediatric epilepsy center of Peking University First Hospital (PKFHPEC) between 2014 and 2018. These patients were selected for retrospective study. The relevant clinical data were collected and analyzed. The surgical prognoses were classified using the Engel classification, and the developmental assessment results were collected. Statistical analysis of the clinical data was performed to analyze the predictors of seizure outcomes and their correlation with developmental outcomes.

RESULTS

All the patients were followed up for more than 3 years, and 98 (86.7%) patients had no seizure recurrence. One year after surgery, the seizure-free rate was 86.7%, which was as high as that at the last follow-up. Cortical dysplasia was the most frequent etiology of DRE in this cohort, accounting for 77.0%. According to the Engel classification, acute postoperative seizure (APOS; p < 0.001) was a predictor of seizure recurrence. No deaths occurred. No unpredicted long-term severe complications occurred except for one ventricular peritoneal shunt. The patients' neurodevelopmental statuses were improved after successful surgery, while the scores of the pre- and postoperative developmental assessments were closely correlated.

CONCLUSIONS

For children who are younger than 3 years old and have DRE and structural abnormalities, early curative treatment can lead to long-term good seizure outcomes and a low complication rate. The development of appropriate strategies for both presurgical evaluation and resection is crucial for the success of surgery.

Effects of inverse methods and spike phases on interictal high-density EEG source reconstruction

OBJECTIVE

To determine the effect of inverse methods and timepoints of interictal epileptic discharges (IEDs) used for high-density electric source imaging (hd-ESI) in pharmacoresistant focal epilepsies.

METHODS

We retrospectively evaluated the hd-ESI and [18F]fluorodeoxyglucose positron emission tomography (18FDG-PET) of 21 operated patients with pharmacoresistant focal epilepsy (Engel I). Volumetric hd-ESI was performed with three different inverse methods such as the inverse solution linearly constrained minimum variance (LCMV, a beamformer method), standardized low resolution electromagnetic tomography (sLORETA) and weighted minimum-norm estimation (wMNE) and at different IED phases. Hd-ESI accuracy was determined by volumetric overlap and distance between hd-ESI source maximum, as well as 18FDG-PET hypometabolic region relative to the resection zone (RZ).

RESULTS

In our cohort, the shortest distances and greatest volumetric overlaps to the RZ were found in the half-rise and peak-phase for all inverse methods. The distance to the RZ was not different between the centroid of the clinical hypothesis-based cluster and the source maximum in peak-phase. However, the distance of the hypothesis-based cluster was significantly shorter compared to the cluster selected by the smallest p-value.

CONCLUSIONS

Hd-ESI provides the greatest accuracy in determining the RZ at the IED half-rise and peak-phase for all applied inverse methods, whereby sLORETA and LCMV were equally accurate.

SIGNIFICANCE

Our results offer guidance in selecting inverse methods and IED phases for hd-ESI, compare the performance of hd-ESI and 18FDG-PET and encourage future studies in investigating the relationship between interictal ESI and 18FDG-PET hypometabolism.

Who are the Better Candidates for Epilepsy Surgery?

The resective epilepsy surgery can be the effective procedure to get seizure-free outcome in these drug resistant epilepsy (DRE) patients. Class I evidence firmly establishes the superiority of epilepsy surgery over medical treatments in both seizure control and quality of life for DRE patients. For the effective identification of optimal surgical candidates, it's essential to understand the prognostic factors of epilepsy surgery based on the surgical methods employed. Established positive prognostic indicators for temporal resection include the presence of hippocampal sclerosis on magnetic resonance imaging (MRI), focal lesions on MRI, unilateral temporal spikes, concordant ictal electroencephalography (EEG), and a history of prolonged febrile convulsion. Potential negative predictors encompass preoperative secondary generalized tonic-clonic seizures, a normal MRI, postoperative EEG spikes, and age at the time of surgery. For neocortical epilepsy, the prognostic factors identified through multivariate analysis were the presence of a discrete lesion, localized hypometabolism on Fluorodeoxyglucose positron emission tomography (FDG-PET), and localized ictal EEG. A significant correlation was found between achieving a seizure-free outcome in no visible lesion on MRI (MR-negative) epilepsy patients and having concordance in two or more presurgical evaluations, specifically in interictal EEG, ictal EEG, FDG-PET, and ictal single-photon emission computed tomography. There was a marked improvement in the seizure-free outcome in MR-negative temporal lobe epilepsy (TLE) by the application of this strategy. The better surgical candidates for epilepsy surgery are the followings: patients displaying a discrete lesion on MRI with concordant video-EEG monitoring (VEM) results, patients diagnosed with unilateral hippocampal sclerosis who have concordant VEM results, patients with unilateral hippocampal sclerosis but discordant VEM results, patients with focal cortical dysplasia and concordant VEM results, and patients diagnosed with MR-negative TLE who exhibit two or more consistent results from presurgical evaluations.

Cerebrovascular glycocalyx damage and microcirculation impairment in patients with temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is increasingly associated with blood-brain barrier dysfunction and microvascular alterations, yet the pathophysiological link is missing. An important barrier function is exerted by the glycocalyx, a gel-like layer coating the endothelium. To explore such associations, we used intraoperative videomicroscopy to quantify glycocalyx and microcirculation properties of the neocortex and hippocampus of 15 patients undergoing resective brain surgery as treatment for drug-resistant TLE, and 15 non-epileptic controls. Fluorescent lectin staining of neocortex and hippocampal tissue was used for blood vessel surface area quantification. Neocortical perfused boundary region, the thickness of the glycocalyx' impaired layer, was higher in patients (2.64 ± 0.52 µm) compared to controls (1.31 ± 0.29 µm), P < 0.01, indicative of reduced glycocalyx integrity in patients. Moreover, erythrocyte flow velocity analysis revealed an impaired ability of TLE patients to (de-)recruit capillaries in response to changing metabolic demands (R2 = 0.75, P < 0.01), indicating failure of neurovascular coupling mechanisms. Blood vessel quantification comparison between intraoperative measurements and resected tissue showed strong correlation (R2 = 0.94, P < 0.01). This is the first report on in vivo assessment of glycocalyx and microcirculation properties in TLE patients, confirming the pivotal role of cerebrovascular changes. Further assessment of the cerebral microcirculation in relation to epileptogenesis might open avenues for new therapeutic targets for drug-resistant epilepsy.

GluK2 Is a Target for Gene Therapy in Drug-Resistant Temporal Lobe Epilepsy

OBJECTIVE

Temporal lobe epilepsy (TLE) is characterized by recurrent seizures generated in the limbic system, particularly in the hippocampus. In TLE, recurrent mossy fiber sprouting from dentate gyrus granule cells (DGCs) crea an aberrant epileptogenic network between DGCs which operates via ectopically expressed GluK2/GluK5-containing kainate receptors (KARs). TLE patients are often resistant to anti-seizure medications and suffer significant comorbidities; hence, there is an urgent need for novel therapies. Previously, we have shown that GluK2 knockout mice are protected from seizures. This study aims at providing evidence that downregulating KARs in the hippocampus using gene therapy reduces chronic epileptic discharges in TLE.

METHODS

We combined molecular biology and electrophysiology in rodent models of TLE and in hippocampal slices surgically resected from patients with drug-resistant TLE.

RESULTS

Here, we confirmed the translational potential of KAR suppression using a non-selective KAR antagonist that markedly attenuated interictal-like epileptiform discharges (IEDs) in TLE patient-derived hippocampal slices. An adeno-associated virus (AAV) serotype-9 vector expressing anti-grik2 miRNA was engineered to specifically downregulate GluK2 expression. Direct delivery of AAV9-anti grik2 miRNA into the hippocampus of TLE mice led to a marked reduction in seizure activity. Transduction of TLE patient hippocampal slices reduced levels of GluK2 protein and, most importantly, significantly reduced IEDs.

INTERPRETATION

Our gene silencing strategy to knock down aberrant GluK2 expression demonstrates inhibition of chronic seizure in a mouse TLE model and IEDs in cultured slices derived from TLE patients. These results provide proof-of-concept for a gene therapy approach targeting GluK2 KARs for drug-resistant TLE patients. ANN NEUROL 2023;94:745-761.

Yield of video electro encephalography for phase 1 pre-surgical evaluation of drug resistant epilepsy in 1200 adults: retrospective study from a tertiary center situated in a lower-middle-income country

INTRODUCTION

Video Electroencephalography (VEEG) is crucial for presurgical evaluation of Drug Refractory Epilepsy (DRE). The yield of VEEG in large volume centers, particularly those situated in Low-and Middle-Income countries (LMIC) is not well studied.

METHODOLOGY

We studied 1200 adults with drug resistant focal epilepsy whose seizures were recorded during VEEG in the epilepsy monitoring unit. VEEG review and analysis was done independently by trained epileptologists. Video EEG and MRI data were examined for concordance in order to generate a hypothesis for the presumed epileptogenic zone.

RESULTS

Analysis of seizure semiology provided information on the symptomatogenic zone in most cases except for 33 (2.75%) patients. A total of 1050 (87.5%) patients showed interictal epileptiform discharges (IEDs) with most (58.3%) showing unilateral IEDs. Most patients (n = 1162, 96.83%) showed ictal EEG discharges of which 951(81.8%) had unilateral ictal onset. Abnormal MRI was seen in 978 (81.5%) patients. Concordance of electroclinical data obtained by analysis of VEEG with MRI abnormality could be established in most patients (63%). Concordance was higher for patients with ictal onset from temporal regions (83.71%) as compared to posterior cortex (55.4%) and frontal regions (43.5%.) CONCLUSION: This study highlights the high yield of VEEG in phase 1 presurgical evaluation in DRE. Systematic evaluation of data from VEEG provided lateralizing and localizing information in most cases. Concordance between VEEG and MRI findings was noted in most patients. These findings support steps to increase referral for pre-surgical evaluation in DRE.