Practice parameter: temporal lobe and localized neocortical resections for epilepsy: report of the Quality Standards Subcommittee of the American Academy of Neurology, in association with the American Epilepsy Society and the American Association of Neurological Surgeons

Optimizing drug-resistant epilepsy identification in the Veterans Health Administration

BACKGROUND

Accurate identification of drug-resistant epilepsy (DRE) is crucial for accurate disease measurement, effective clinical intervention and improved patient outcomes. Prior attempts to define DRE in administrative data using the 2010 International League against Epilepsy (ILAE) criteria have faced complexities.

METHODS

This retrospective study utilized national administrative data from the Veterans Health Administration (VHA) to identify patients with possible DRE. This was a multicenter national cohort that uses a common, non-commercial medical record system. A panel of six epileptologists conducted chart reviews to identify DRE using the 2010 ILAE criteria. Logistic regression was used to analyze epilepsy-related variables of interest to develop algorithms identifying DRE.

RESULTS

Among 260 included patients, 93 (35.8 %) had DRE, 148 (56.9 %) did not have DRE, and 19 (7.3 %) were undetermined. Out of 96 algorithms assessed, the best-performing algorithm had a high accuracy (F1 score=0.726) and defined DRE as those on ≥ 3 ASMs in addition to those on ≥ 2 ASMs for ≥ 365 days with at least one intractable ICD code. The algorithm demonstrated high sensitivity (0.74), specificity (0.81), and area under the curve (AUC 0.78). Factors such as age, number of ASMs, EEG, and MRI procedures, and intractable epilepsy ICD codes were associated with DRE.

DISCUSSION

Our optimal algorithm for DRE identification is like previously published algorithms that determined the importance of number and duration of ASMs. However, it differs in the particular combination of factors that best identified DRE. These differences highlight the importance of fine-tuning algorithms for specific care settings. Further validation in a larger, more heterogenous cohort are needed to determine our algorithm's applicability and potential impact.

Surgical: Resection/Destructive Procedures

Surgical resection and ablation are powerful tools in the treatment of medically refractory epilepsy. In this study, we review a broad array of resective and ablative procedures available to the epilepsy surgeon to address surgical epileptic disease. Here, we aim to provide a brief overview of a very broad category of treatments to provide a better understanding of the breadth of treatments available to providers and patients.

Enlarged perivascular space in the temporal lobe as a prognostic marker in temporal lobe epilepsy with hippocampal sclerosis

OBJECTIVE

This study was undertaken to investigate the regional burden of enlarged perivascular spaces (EPVSs) in patients with temporal lobe epilepsy with hippocampal sclerosis (TLE-HS) and explore its prognostic relevance.

METHODS

In this retrospective observational study, EPVSs in the temporal lobe (T-EPVS), centrum semiovale (CS-EPVS), basal ganglia (BG-EPVS), midbrain, and hippocampus were visually rated in 68 treatment-naïve patients with TLE-HS. Regional EPVS burden was dichotomized into high and low degrees (cutoff: >10 for BG-EPVS/T-EPVS; >20 for CS-EPVS). Cox proportional hazards models were used to determine the potential predictors of seizure freedom (SF; no seizure for >1 year) and delayed SF (SF achieved >6 months after initiating antiseizure medication [ASM]). Multivariate logistic regression using stepwise variable selection based on the Akaike information criterion was performed to investigate whether EPVS burden was associated with medical refractoriness (never achieving SF).

RESULTS

Of the 68 patients, 20 were classified into the refractory group (29.4%). The high T-EPVS group had an older epilepsy onset (37.3 ± 12.3 vs. 26.5 ± 13.0 years, p = .005), higher pretreatment seizure density (median = 12.0, interquartile range [IQR] = 5.0-20.0 vs. 4.0, IQR = 2.0-10.5, p = .008), and lower focal to bilateral tonic-clonic seizure prevalence (13.3% vs. 73.6%, p < .001) than the low T-EPVS group. High T-EPVS burden (odds ratio [OR] = 10.908, 95% confidence interval [CI] = 1.895-62.789) was an independent predictor of medial refractoriness, along with female sex (OR = 12.906, 95% CI = 2.214-75.220) and ASM treatment duration (OR = .985, 95% CI = .971-.999). The low T-EPVS group had higher probability of achieving delayed SF than the high T-EPVS group (pLog-rank = .030, pCox regression = .038), whereas the probability of achieving SF was comparable between the two groups (pLog-rank = .053, pCox regression = .146).

SIGNIFICANCE

Increased T-EPVS burden may serve as an imaging marker of unfavorable prognosis in patients with TLE-HS, underscoring the potential role of perivascular dysfunction in diminished ASM response.

Implementing Guidelines and Measures in Epilepsy Care

ABSTRACT

People with epilepsy must receive up-to-date, high-quality care that aligns with current understanding of basic disease mechanisms, improved diagnostic testing, and evolving medical and surgical treatments. Varying progress has been made in identifying, measuring, and mitigating epilepsy care gaps. Epilepsy guidelines and quality measures should be developed using rigorous processes informed by systematic reviews of best evidence in conjunction with prioritization of need. Epilepsy measures help operationalize guidelines and practice parameters. Most epilepsy quality indicators are process-based metrics defined by delivering care to the patient. Systematic and reliable tracking and documentation of seizure frequency using consistent language is required as a patient-reported outcome within individuals over time and across populations. Emerging literature has demonstrated gaps in epilepsy care, perhaps highlighting limitations in the dissemination and implementation of guidelines and quality measures in clinical practice. Quality improvement methods applied to clinical data registries and learning health systems may afford new opportunities to iteratively, collaboratively, and feasibly disseminate guidelines and quality measures, measure epilepsy care quality, allow for the testing of interventions to mitigate identified care gaps, and, ultimately, improve care for patients with epilepsy.

Seizure outcomes and associated factors in adults with unilateral mesial temporal lobe epilepsy undergoing surgery

OBJECTIVE

To analyze postoperative seizure outcomes and factors associated with unfavorable seizure control (Engel III-IV) in adults with drug-resistant unilateral mesial temporal epilepsy who underwent temporal lobectomy.

METHODS

This was an observational, longitudinal, and retrospective study. A descriptive analysis of sociodemographic, clinical, and paraclinical characteristics was performed. The incidence rate of inadequate seizure control was calculated, and a Kaplan-Meier curve was reported. Cox regression analysis was conducted to identify factors associated with unfavorable outcomes.

RESULTS

A total of 285 patients were included, 56.4% were women, and 49.12% underwent standard temporal lobectomy. Engel I were achieved in 70.87% of patients, while 6.31% experienced postsurgical complications. The estimated incidence rate of unfavorable outcomes was 3.87 cases per 100 person-years (95% CI: 3.51-4.27). Cox regression analysis indicated that patients with a temporal functional deficit zone, as identified by neuropsychological testing, had a 55.34% lower risk of an unfavorable outcome (adjusted HR: 0.4466, 95% CI: 0.236-0.854) compared to those with non-conclusive or extratemporal deficits. Concordance between video-electroencephalogram and brain magnetic resonance imaging findings in patients with right-sided lesions was also a protective factor (adjusted HR: 0.1868, 95% CI: 0.06-0.578). Discontinuation of anti-seizure treatment significantly increased the risk of an unfavorable outcome (adjusted HR: 6.718, 95% CI: 3.309-13.64).

CONCLUSION

Temporal lobe epilepsy surgery can achieve long-term seizure control in a significant proportion of patients. Neuropsychological assessment and concordance between MRI and video-EEG are essential presurgical factors for favorable outcomes. Additionally, patients should continue with antiepileptic treatment post-surgery to prevent seizure recurrence.

Do We Practice What We Preach? Examining Barriers to Timely Epilepsy Surgery Referrals

Surveying neurologist perspectives and knowledge of epilepsy surgery to identify barriers to surgery referral Namal U. Seneviratne Objective: Epilepsy surgery is an effective means of treating medically refractory epilepsy (MRE), but it remains underused. We aimed to analyze the perspectives and knowledge of referring neurologists in the New York metropolitan area, who serve a large epilepsy population. Methods: We adapted a previous Canadian survey by Roberts et al, adding questions regarding demographic descriptors, insurance coverage, training and practice details, and perceived social barriers for patients. We surveyed neurologists directly affiliated with Montefiore Medical Center and those referring to Montefiore's Comprehensive Epilepsy Center. Participants had 10 weeks to fill out an online Qualtrics survey with weekly reminders. Results: Of 117 neurologists contacted, 51 eligible neurologists completed the survey (63.8% Montefiore, 35.0% referring group). A high proportion of the results were from epilepsy-trained individuals (41.2%) and neurologists who graduated residency ≤19 years ago (80.4%). About 80.4% of respondents felt that epilepsy surgery is safe, but only 56.9% would refer a patient for surgical workup after two failed trials of antiseizure medications. Epileptologists and providers with a larger volume of epilepsy patients and electroencephalogram readings had better knowledge of the epilepsy surgery workup guidelines. When asked to rank social barriers to patients receiving surgery, participants were most concerned about lack of social support, financial insecurity, and a patient's dual role as a caregiver. Significance: Our study suggests continued reluctance of neurologists regarding epilepsy surgery and deficiencies in the knowledge and adherence to the recommended guidelines. In the context of prior studies, these results showed and improved understanding of the definition of MRE (80.4%) and an increased likelihood to refer eligible patients as early as possible (78.4%) in line with current consensus recommendations. The finding that epilepsy-trained and more epilepsy/electroencephalogram-facing neurologists showed a better understanding of the guidelines suggests that the increased education efforts should be targeted at nonepileptologists.

The effect of Vagus nerve stimulation (VNS) on seizure control, cognitive function, and quality of life in individuals with drug-resistant epilepsy: A systematic review article

OBJECTIVES

To evaluate the effect of vagus nerve stimulation (VNS) on seizure control, cognitive functions, and quality of life in individuals with drug-resistant epilepsy.

METHODS

An extensive search of electronic databases was carried out in order to carry out this systematic review. The databases Google Scholar, Embase, PubMed, and the Cochrane Library were searched first to carryout gray literature. To reduce the quantity of pointless studies in the advanced search, the search is limited to "human studies" and "English language" publications only. Combining keywords and Medical Subject Headings (MeSH) terms like ("Vagus Nerve Stimulation" OR "VNS") AND ("Epilepsy" OR "Seizure Control") AND ("Cognitive Function" OR "Quality of Life"). Studies that have been published up to November 30/2023 were included.

RESULTS

The search strategy yielded a total of 392 relevant studies. The mean age of participant's ranges from 11 years to 33 years. The duration of follow-up ranging from 6 to 36 months. Eleven studies were included in the review. The mean≥50% response rate after VNS therapy was 56.94% ranged from 48.90% to 83.00%. Four and three studies provided information about Quality of Life in Epilepsy Inventory (QOLIE-31) and The Liverpool Seizure Severity Scale (LSSS) questionnaires respectively.

SIGNIFICANCE

Epilepsy is a chronic disease characterized by sudden abnormal discharge of brain neurons, which leads to transient brain dysfunction and the presence of spontaneous recurrent seizures. Vagus nerve stimulation has recently been proposed as a potential tool in the treatment of seizure, depressive symptoms, and cognitive impairments. There has been variation in the effects of VNS treatment on seizure control, cognitive functions, and quality of life among patients with drug-resistant epilepsy. So, a comprehensive review of exciting literature is important to see the pooled effect. Previous systematic review and meta-analysis papers were mostly randomized control trial type with specific diseases. The use of a wider variety of study designs than only randomized controlled trials is important. So, we included retrospective and prospective cohort studies in addition to randomized control trials. This enables a more thorough assessment of the connection between quality of life, cognitive function, and vagus nerve stimulation. In addition, the paper looks at a wide range of disease kinds and patterns. We have established a uniform and comprehensive approach throughout the selected studies by mandating the inclusion of all three crucial parameters: vagus nerve stimulation, cognitive function, and quality of life.

PLAIN LANGUAGE SUMMARY

This systematic review examined 392 relevant studies on vagus nerve stimulation (VNS) therapy, with participants ranging from 11 to 33 years old and follow-up durations of 6-36 months. Eleven studies were included, and the mean response rate after VNS therapy was 56.94%, ranging from 48.90% to 83.00%. The review also reported on quality of life and cognitive function, and seizure severity frequency result from several studies.

Stereotactic radiosurgery for medically refractory non-lesional epilepsy: A case-based Radiosurgery Society (RSS) practice review

INTRODUCTION

Medically refractory epilepsy (MRE) occurs in about 30 % of patients with epilepsy, and the treatment options available to them have evolved over time. The classic treatment for medial temporal lobe epilepsy (mTLE) is anterior temporal lobectomy (ATL), but an initiative to find less invasive options has resulted in treatments such as neuromodulation, ablative procedures, and stereotactic radiosurgery (SRS). SRS has been an appealing non-invasive option and has developed an increasing presence in the literature over the last few decades. This article provides an overview of SRS for MRE with two example cases, and we discuss the optimal technique as well as the advantages, alternatives, and risks of this therapeutic option.

CASES

We present two example cases of patients with MRE, who were poor candidates for invasive surgical treatment options and underwent SRS. The first case is a 65-year-old female with multiple medical comorbidities, whose seizure focus was localized to the left temporal lobe, and the second case is a 19-year-old male with Protein C deficiency and medial temporal lobe sclerosis. Both patients underwent SRS to targets within the medial temporal lobe, and both achieve significant improvements in seizure frequency and severity.

DISCUSSION

SRS has generally been shown to be inferior to ATL for seizure reduction in medically refractory mTLE. However, there are patients with epilepsy for which SRS can be considered, such as patients with medical comorbidities that make surgery high risk, patients with epileptogenic foci in eloquent cortex, patients who have failed to respond to surgical management, patients who choose not to undergo surgery, and patients with geographic constraints to epilepsy centers. Patients and their physicians should be aware that SRS is not risk-free. Patients should be counseled on the latency period and monitored for risks such as delayed cerebral edema, visual field deficits, and radiation necrosis.

Association Between Postsurgical Functional Connectivity and Seizure Outcome in Patients With Temporal Lobe Epilepsy

BACKGROUND AND OBJECTIVES

Despite the success of presurgical network connectivity studies in predicting short-term (1-year) seizure outcomes, later seizure recurrence occurs in some patients with temporal lobe epilepsy (TLE). To uncover contributors to this recurrence, we investigated the relationship between functional connectivity and seizure outcomes at different time points after surgery in these patients.

METHODS

Patients included were clinically diagnosed with unilateral mesial TLE after a standard clinical evaluation and underwent selective amygdalohippocampectomy. Healthy controls had no history of seizures or head injury. Using resting-state fMRI, we assessed the postsurgical functional connectivity node strength, computed as the node's total strength to all other nodes, between seizure-free (Engel Ia-Ib) and nonseizure-free (Engel Ic-IV) acquisitions. The change over time after surgery in different outcome groups in these nodes was also characterized.

RESULTS

Patients with TLE (n = 32, mean age: 43.1 ± 11.9 years; 46.8% female) and 85 healthy controls (mean age: 37.7 ± 13.5 years; 48.2% female) were included. Resting fMRI was acquired before surgery and at least once after surgery in each patient (range 1-4 scans, 5-60 months). Differences between patients with (n = 30) and without (n = 18) seizure freedom were detected in the posterior insula ipsilateral to the resection (I-PIns: 95% CI -154.8 to -50.1, p = 2.8 × 10-4) and the bilateral central operculum (I-CO: 95% CI -163.2 to -65.1, p = 2.6 × 10-5, C-CO: 95% CI -172.7 to -55.8, p = 2.8 × 10-4). In these nodes, only those who were seizure-free had increased node strength after surgery that increased linearly over time (I-CO: 95% CI 1.0-5.2, p = 4.2 × 10-3, C-CO: 95% CI 1.0-5.2, p = 5.5 × 10-3, I-PIns: 95% CI 1.6-5.5, p = 0.9 × 10-3). Different outcome groups were not distinguished by node strength before surgery.

DISCUSSION

The findings suggest that network evolution in the first 5 years after selective amygdalohippocampectomy surgery is related to seizure outcomes in TLE. This highlights the need to identify presurgical and surgical conditions that lead to disparate postsurgical trajectories between seizure-free and nonseizure-free patients to identify potential contributors to long-term seizure outcomes. However, the lack of including other surgical approaches may affect the generalizability of the results.

Transcranial magnetic stimulation and magnetoencephalography are feasible alternatives to invasive methods in optimizing responsive neurostimulation device placement

Responsive neurostimulation (RNS) is a treatment option for patients with refractory epilepsy when surgical resection is not possible due to overlap of the irritative zone and eloquent cortex. Presurgical evaluations for RNS placement typically rely on invasive methods. This study investigated the potential of transcranial magnetic stimulation (TMS) and magnetoencephalography (MEG) to provide key presurgical information non-invasively. We hypothesized that these non-invasive methods may assist in optimizing RNS placement by providing useful information for seizure localization by MEG and eloquent cortex mapping by TMS. A retrospective chart review identified nine patients who underwent RNS placement (mean age = 20.4 years [SD = 5.6], two-thirds were female). Characterization of the irritative zone using MEG was successful in eight of nine patients. Non-invasive mapping of relevant eloquent cortex was attempted in all patients. TMS was successful in eight of nine patients, and MEG was successful in two of six patients. Importantly, patients mapped with non-invasive modalities experienced an average seizure reduction of 77 % at their most recent clinic visit, compared to 75 % seizure reduction in those with invasive evaluations, indicating appropriate RNS placement. These data demonstrate that TMS and MEG can provide key information for RNS and may be feasible alternatives to invasive methods for assisting in decision making regarding RNS placement. Non-invasive methods for determining RNS placement have a high rate of success when data from multiple non-invasive modalities converge and can inform more accurate placement of intracranial electrodes prior to RNS placement or mitigate their need.

A Comprehensive Review of Recent Trends in Surgical Approaches for Epilepsy Management

Epilepsy is a neurological disorder that affects millions of people worldwide, with a significant proportion of patients experiencing drug-resistant epilepsy, where seizures remain uncontrolled despite medical treatment. This review evaluates the latest surgical techniques for managing epilepsy, focusing on their effectiveness, safety, and the ongoing challenges that hinder their broader adoption. We explored various databases including PubMed, Google Scholar, and Cochrane Library to look for relevant literature using the following keywords: Epilepsy, Resective Surgery, Corpus Collectumy, and Antiepileptic Drugs. A total of 54 relevant articles were found and thoroughly explored. Recent advancements in surgical interventions include resective procedures such as anterior temporal lobectomy, corpus callosotomy, and hemispherectomy, which have been particularly effective in reducing seizures for specific types of epilepsy. Minimally invasive techniques, including laser interstitial thermal therapy and focused ultrasound, are increasingly being used, offering promising outcomes for certain patient groups. Additionally, neuromodulation methods such as deep brain stimulation, vagus nerve stimulation, and responsive neurostimulation provide alternative treatment options, especially for patients who are not suitable candidates for resective surgery. Despite these advancements, the full potential of epilepsy surgery is often underutilized due to various challenges. Inconsistent referral practices, a lack of standardized surgical protocols, and significant socioeconomic barriers continue to limit access to these procedures. Addressing these issues through improved referral processes, better education for healthcare providers and patients, and ensuring equitable access to advanced surgical treatments is crucial for optimizing patient outcomes. Future research should focus on overcoming these barriers and assessing long-term outcomes to further enhance the care of patients with epilepsy.

Knowledge of epilepsy surgery: A survey among medical doctors in Nigeria

BACKGROUND

Epilepsy surgery has been shown to significantly improve the quality of life of patients with drug resistant epilepsy. Despite this, epilepsy surgery remains remarkably underutilized in Nigeria. There are high misconceptions about epilepsy and its management among physicians and trainees.

METHODS

This study aims to identify knowledge gaps in epilepsy surgery among medical doctors in Nigeria and factors associated with their level of knowledge of the procedure. A cross-sectional study was carried out among 566 medical doctors in Nigeria, at different levels of post-graduate training (House officers, Medical officers, Resident doctors and Consultants). An online survey with a 24-item questionnaire adapted from a standardized pro forma was utilized. Binary and multiple logistic regression were used to identify associations between the independent variable and outcome variable (good or poor knowledge) RESULTS: Majority of the respondents were medical officers (post-intern physicians) comprising 65.7 % of the participants. Significant predictors of poor knowledge included being a medical officer [P=0.006], working in north-central [P=0.017] and north-western Nigeria [P=0.045], seeing less than 20 epilepsy patients per month [1-10 patients, P=0.015; 11-20 patients, P=0.011], and enrolment in online epilepsy course [P=0.004].

CONCLUSION

Comprehensive education and awareness about epilepsy surgery are important in overcoming the knowledge gap and improving access to care.

Testing an online screening tool for epilepsy surgery evaluation

BACKGROUND

 Epilepsy surgery is recognized for its effectiveness in controlling seizures in a significant number of patients with drug-resistant epilepsy. Despite this, there remains a notable deficiency in referring these patients for video-electroencephalogram (EEG) monitoring and surgical evaluation. Addressing this gap, the Canadian Appropriateness of Epilepsy Surgery (CASES), an online tool for epilepsy surgery evaluation (www.epilepsycases.com), was developed to aid physicians in the referral process of patients with refractory epilepsy to surgical assessments.

OBJECTIVE

 The present study aimed to evaluate the utility of CASES in identifying candidates for epilepsy surgery, thereby facilitating clinical decision-making for patients with drug-resistant epilepsy.

METHODS

 A cross-sectional analysis was conducted using the CASES platform to assess surgical candidacy among individuals with epilepsy. Participants were selected among those receiving care at the Epilepsy Clinic of the Neurology Service, Hospital de Clínicas de Porto Alegre, Brazil, over a 3-month period. The study cohort included 211 patients. Data were systematically extracted from patient medical records or collected during clinical appointments.

RESULTS

 Of the evaluated cohort, 59.6% were identified as potential candidates for video-EEG monitoring and subsequent surgical evaluation. Factors significantly associated with recommendations for video-EEG and surgical assessment included seizure frequency, the number of antiseizure medications (ASMs) trialed, and the occurrence of drug-related adverse effects.

CONCLUSION

 The CASES showed significant potential in guiding recommendations for video-EEG monitoring and facilitating referrals for epilepsy surgery. This tool may not only enhance patient treatments and outcomes but also contribute to cost savings in epilepsy management in both the short and long term.

The sixth sense: how much does interictal intracranial EEG add to determining the focality of epileptic networks?

Intracranial EEG is used for two main purposes: to determine (i) if epileptic networks are amenable to focal treatment and (ii) where to intervene. Currently, these questions are answered qualitatively and differently across centres. There is a need to quantify the focality of epileptic networks systematically, which may guide surgical decision-making, enable large-scale data analysis and facilitate multi-centre prospective clinical trials. We analysed interictal data from 101 patients with drug-resistant epilepsy who underwent pre-surgical evaluation with intracranial EEG at a single centre. We chose interictal data because of its potential to reduce the morbidity and cost associated with ictal recording. Sixty-five patients had unifocal seizure onset on intracranial EEG, and 36 were non-focal or multi-focal. We quantified the spatial dispersion of implanted electrodes and interictal intracranial EEG abnormalities for each patient. We compared these measures against the '5 Sense Score,' a pre-implant prediction of the likelihood of focal seizure onset, assessed the ability to predict unifocal seizure onset by combining these metrics and evaluated how predicted focality relates to subsequent treatment and outcomes. The spatial dispersion of intracranial EEG electrodes predicted network focality with similar performance to the 5-SENSE score [area under the receiver operating characteristic curve = 0.68 (95% confidence interval 0.57, 0.78)], indicating that electrode placement accurately reflected pre-implant information. A cross-validated model combining the 5-SENSE score and the spatial dispersion of interictal intracranial EEG abnormalities significantly improved this prediction [area under the receiver operating characteristic curve = 0.79 (95% confidence interval 0.70, 0.88); P < 0.05]. Predictions from this combined model differed between surgical- from device-treated patients with an area under the receiver operating characteristic curve of 0.81 (95% confidence interval 0.68, 0.85) and between patients with good and poor post-surgical outcome at 2 years with an area under the receiver operating characteristic curve of 0.70 (95% confidence interval 0.56, 0.85). Spatial measures of interictal intracranial EEG abnormality significantly improved upon pre-implant predictions of network focality by area under the receiver operating characteristic curve and increased sensitivity in a single-centre study. Quantified focality predictions related to ultimate treatment strategy and surgical outcomes. While the 5-SENSE score weighed for specificity in their multi-centre validation to prevent unnecessary implantation, sensitivity improvement found in our single-centre study by including intracranial EEG may aid the decision on whom to perform the focal intervention. We present this study as an important step in building standardized, quantitative tools to guide epilepsy surgery.

Machine learning algorithm for predicting seizure control after temporal lobe resection using peri-ictal electroencephalography

Brain resection is curative for a subset of patients with drug resistant epilepsy but up to half will fail to achieve sustained seizure freedom in the long term. There is a critical need for accurate prediction tools to identify patients likely to have recurrent postoperative seizures. Results from preclinical models and intracranial EEG in humans suggest that the window of time immediately before and after a seizure ("peri-ictal") represents a unique brain state with implications for clinical outcome prediction. Using a dataset of 294 patients who underwent temporal lobe resection for seizures, we show that machine learning classifiers can make accurate predictions of postoperative seizure outcome using 5 min of peri-ictal scalp EEG data that is part of universal presurgical evaluation (AUC 0.98, out-of-group testing accuracy > 90%). This is the first approach to seizure outcome prediction that employs a routine non-invasive preoperative study (scalp EEG) with accuracy range likely to translate into a clinical tool. Decision curve analysis (DCA) shows that compared to the prevalent clinical-variable based nomogram, use of the EEG-augmented approach could decrease the rate of unsuccessful brain resections by 20%.

Underutilization of Neurodiagnostic Resources in Drug-Resistant Epilepsy

Use of Recommended Neurodiagnostic Evaluation Among Patients With Drug-Resistant Epilepsy Matthew Spotnitz, Cameron D Ekanayake, Anna Ostropolets, Guy M McKhann, Hyunmi Choi, Ruth Ottman, Alfred I Neugut, George Hripcsak, Karthik Natarajan, Brett E Youngerman. JAMA Neurol . 2024;81(5):499–506. DOI: 10.1001/jamaneurol.2024.0551. PMID: 38557864 Importance: Interdisciplinary practice parameters recommend that patients with drug-resistant epilepsy (DRE) undergo comprehensive neurodiagnostic evaluation, including presurgical assessment. Reporting from specialized centers suggests long delays to referral and underuse of surgery; however, longitudinal data are limited to characterize neurodiagnostic evaluation among patients with DRE in more diverse US settings and populations. Objective: To examine the rate and factors associated with neurodiagnostic studies and comprehensive evaluation among patients with DRE within 3 US cohorts. Design, setting, and participants: A retrospective cross-sectional study was conducted using the Observational Medical Outcomes Partnership Common Data Model including US multistate Medicaid data, commercial claims data, and Columbia University Medical Center (CUMC) electronic health record data. Patients meeting a validated computable phenotype algorithm for DRE between January 1, 2015, and April 1, 2020, were included. No eligible participants were excluded. Exposure: Demographic and clinical variables were queried. Main outcomes and measures: The proportion of patients receiving a composite proxy for comprehensive neurodiagnostic evaluation, including (1) magnetic resonance or other advanced brain imaging, (2) video-electroencephalography, and (3) neuropsychological evaluation within 2 years of meeting the inclusion criteria. Results: A total of 33 542 patients with DRE were included in the Medicaid cohort, 22 496 in the commercial insurance cohort, and 2741 in the CUMC database. A total of 31 516 patients (53.6%) were women. The proportion of patients meeting the comprehensive evaluation main outcome in the Medicaid cohort was 4.5% (n  = 1520); in the commercial insurance cohort, 8.0% (n  = 1796); and in the CUMC cohort, 14.3% (n  = 393). Video-electroencephalography (24.9% Medicaid, 28.4% commercial, and 63.2% CUMC) and magnetic resonance imaging of the brain (35.6% Medicaid, 43.4% commercial, and 52.6% CUMC) were performed more regularly than neuropsychological evaluation (13.0% Medicaid, 16.6% commercial, and 19.2% CUMC) or advanced imaging (3.2% Medicaid, 5.4% commercial, and 13.1% CUMC). Factors independently associated with greater odds of evaluation across all 3 data sets included the number of inpatient and outpatient nonemergency epilepsy visits and focal rather than generalized epilepsy. Conclusions and relevance: The findings of this study suggest there is a gap in the use of diagnostic studies to evaluate patients with DRE. Care setting, insurance type, frequency of nonemergency visits, and epilepsy type are all associated with evaluation. A common data model can be used to measure adherence to best practices across a variety of observational data sources.

Localizing hidden Interictal Epileptiform Discharges with simultaneous intracerebral and scalp high-density EEG recordings

BACKGROUND

Scalp EEG is one of the main tools in the clinical evaluation of epilepsy. In some cases intracranial Interictal Epileptiform Discharges (IEDs) are not visible from the scalp. Recent studies have shown the feasibility of revealing them in the EEG if their timings are extracted from simultaneous intracranial recordings, but their potential for the localization of the epileptogenic zone is not yet well defined.

NEW METHOD

We recorded simultaneous high-density EEG (HD-EEG) and stereo-electroencephalography (SEEG) during interictal periods in 8 patients affected by drug-resistant focal epilepsy. We identified IEDs in the SEEG and systematically analyzed the time-locked signals on the EEG by means of evoked potentials, topographical analysis and Electrical Source Imaging (ESI). The dataset has been standardized and is being publicly shared.

RESULTS

Our results showed that IEDs that were not clearly visible at single-trials could be uncovered by averaging, in line with previous reports. They also showed that their topographical voltage distributions matched the position of the SEEG electrode where IEDs had been identified, and that ESI techniques can reconstruct it with an accuracy of ∼2 cm. Finally, the present dataset provides a reference to test the accuracy of different methods and parameters.

COMPARISON WITH EXISTING METHODS

Our study is the first to systematically compare ESI methods on simultaneously recorded IEDs, and to share a public resource with in-vivo data for their evaluation.

CONCLUSIONS

Simultaneous HD-EEG and SEEG recordings can unveil hidden IEDs whose origins can be reconstructed using topographical and ESI analyses, but results depend on the selected methods and parameters.

Altered structural network in temporal lobe epilepsy with focal to bilateral tonic-clonic seizures

OBJECTIVES

This study aims to investigate whether alterations in white matter topological networks are associated with focal to bilateral tonic-clonic seizures (FBTCS) in temporal lobe epilepsy (TLE). Additionally, we investigated the variables contributing to memory impairment in TLE.

METHODS

This cross-sectional study included 88 unilateral people with TLE (45 left/43 right), and 42 healthy controls. Graph theory analysis was employed to compare the FBTCS (+) group (n = 51) with the FBTCS (-) group (n = 37). The FBTCS (+) group was subcategorized into current-FBTCS (n = 31) and remote-FBTCS (n = 20), based on the history of FBTCS within 1 year or longer than 1 year before scanning, respectively. We evaluated the discriminatory power of topological network properties by receiver operating characteristic (ROC) analysis. Generalized linear models (GLMs) were employed to investigate variables associated with memory impairment in TLE.

RESULTS

Global efficiency (Eg) was significantly reduced in the FBTCS (+) group, especially in the current-FBTCS subgroup. Greater disruption of regional properties in the ipsilateral occipital and temporal association cortices was observed in the FBTCS (+) group. ROC analysis revealed that Eg, normalized characteristic shortest path length, and nodal efficiency of the ipsilateral middle temporal gyrus could distinguish between FBTCS (+) and FBTCS (-) groups. Additionally, GLMs linked the occurrence of current FBTCS with poorer verbal memory outcomes in TLE.

INTERPRETATION

Our study suggests that abnormal networks could be the structural basis of seizure propagation in FBTCS. Strategies aimed at reducing the occurrence of FBTCS could potentially improve the memory outcomes in people with TLE.

Non-lesional epilepsy does not necessarily convey poor outcomes after invasive monitoring followed by resection or thermal ablation

OBJECTIVE

We aimed to compare outcomes including seizure-free status at the last follow-up in adult patients with medically refractory focal epilepsy identified as lesional vs. non-lesional based on their magnetic resonance imaging (MRI) findings who underwent invasive evaluation followed by subsequent resection or thermal ablation (LiTT).

METHODS

We identified 88 adult patients who underwent intracranial monitoring between 2014 and 2021. Of those, 40 received resection or LiTT, and they were dichotomized based on MRI findings, as lesional (N = 28) and non-lesional (N = 12). Patient demographics, seizure characteristics, non-invasive interventions, intracranial monitoring, and surgical variables were compared between the groups. Postsurgical seizure outcome at the last follow-up was rated according to the Engel classification, and postoperative seizure freedom was determined by Kaplan-Meyer survival analysis. Statistical analyses employed Fisher's exact test to compare categorical variables, while a t-test was used for continuous variables.

RESULTS

There were no differences in baseline characteristics between groups except for more often noted PET abnormality in the lesional group (p = 0.0003). 64% of the lesional group and 57% of the non-lesional group received surgical resection or LiTT (p = 0.78). At the last follow-up, 78.5% of the patients with lesional MRI findings achieved Engel I outcomes compared to 66.7% of non-lesional patients (p = 0.45). Kaplan-Meier curves did not show a significant difference in seizure-free duration between both groups after surgical intervention (p = 0.49).

SIGNIFICANCE

In our sample, the absence of lesion on brain MRI was not associated with worse seizure outcomes in adult patients who underwent invasive intracranial monitoring followed by resection or thermal ablation.

Stereotactic radiosurgery for haemorrhagic cerebral cavernous malformation: a multi-institutional, retrospective study

BACKGROUND

Cerebral cavernous malformations (CCMs) frequently manifest with haemorrhages. Stereotactic radiosurgery (SRS) has been employed for CCM not suitable for resection. Its effect on reducing haemorrhage risk is still controversial. The aim of this study was to expand on the safety and efficacy of SRS for haemorrhagic CCM.

METHODS

This retrospective multicentric study included CCM with at least one haemorrhage treated with single-session SRS. The annual haemorrhagic rate (AHR) was calculated before and after SRS. Recurrent event analysis and Cox regression were used to evaluate factors associated with haemorrhage. Adverse radiation effects (AREs) and occurrence of new neurological deficits were recorded.

RESULTS

The study included 381 patients (median age: 37.5 years (Q1-Q3: 25.8-51.9) with 414 CCMs. The AHR from diagnosis to SRS excluding the first haemorrhage was 11.08 per 100 CCM-years and was reduced to 2.7 per 100 CCM-years after treatment. In recurrent event analysis, SRS, HR 0.27 (95% CI 0.17 to 0.44), p<0.0001 was associated with a decreased risk of haemorrhage, and the presence of developmental venous anomaly (DVA) with an increased risk, HR 1.60 (95% CI 1.07 to 2.40), p=0.022. The cumulative risk of first haemorrhage after SRS was 9.4% (95% CI 6% to 12.6%) at 5 years and 15.6% (95% CI% 9 to 21.8%) at 10 years. Margin doses> 13 Gy, HR 2.27 (95% CI 1.20 to 4.32), p=0.012 and the presence of DVA, HR 2.08 (95% CI 1.00 to 4.31), p=0.049 were factors associated with higher probability of post-SRS haemorrhage. Post-SRS haemorrhage was symptomatic in 22 out of 381 (5.8%) patients, presenting with transient (15/381) or permanent (7/381) neurological deficit. ARE occurred in 11.1% (46/414) CCM and was responsible for transient neurological deficit in 3.9% (15/381) of the patients and permanent deficit in 1.1% (4/381) of the patients. Margin doses >13 Gy and CCM volume >0.7 cc were associated with increased risk of ARE.

CONCLUSION

Single-session SRS for haemorrhagic CCM is associated with a decrease in haemorrhage rate. Margin doses ≤13 Gy seem advisable.

The anterior sylvian point as a reliable landmark for the anterior temporal lobectomy in mesial temporal lobe epilepsy: technical note, case series, and cadaveric dissection

Introduction

Mesial temporal lobe epilepsy (MTLE) is one of the most prevalent forms of focal epilepsy in surgical series, particularly among adults. Over the decades, different surgical strategies have been developed to address drug-resistant epilepsy while safeguarding neurological and cognitive functions. Among these strategies, anterior temporal lobectomy (ATL), involving the removal of the temporal pole and mesial temporal structures, has emerged as a widely employed technique. Numerous modifications have been proposed to mitigate the risks associated with aphasia, cognitive issues, and visual field defects.

Methods

Our approach is elucidated through intraoperative and cadaveric dissections, complemented by neuroradiological and cadaveric measurements of key anatomical landmarks. A retrospective analysis of patients with drug-resistant MTLE who were treated using our ATL technique at IRCCS Neuromed (Pozzilli) is presented.

Results

A total of 385 patients were treated with our ATL subpial technique anatomically focused on the anterior Sylvian point (ASyP). The mean FU was 9.9 ± 5.4 years (range 1-24). In total, 84%of patients were free of seizures during the last follow-up, with no permanent neurological deficits. Transient defects were as follows: aphasia in 3% of patients, visual field defects in 2% of patients, hemiparesis in 2% of patients, and cognitive/memory impairments in 0.8% of patients. In cadaveric dissections, the ASyP was found at a mean distance from the temporal pole of 3.4 ± 0.2 cm (range 3-3.8) at the right side and 3.5 ± 0.2 cm (3.2-3.9) at the left side. In neuroimaging, the ASyP resulted anterior to the temporal horn tip in all cases at a mean distance of 3.2 ± 0.3 mm (range 2.7-3.6) at the right side and 3.5 ± 0.4 mm (range 2.8-3.8) at the left side.

Discussion

To the best of our knowledge, this study first introduces the ASyP as a reliable and reproducible cortical landmark to perform the ATL to overcome the patients' variabilities, the risk of Meyer's loop injury, and the bias of intraoperative measurements. Our findings demonstrate that ASyP can be a safe cortical landmark that is useful in MTLE surgery because it is constantly present and is anterior to risky temporal regions such as temporal horn and language networks.

Surgical management of status epilepticus: A systematic review

Status Epilepticus (SE), unresponsive to medical management, is associated with high morbidity and mortality. Surgical management is typically considered in these refractory cases. The best surgical approach for affected patients remains unclear; however, given the lack of controlled trials exploring the role of surgery. We performed a systematic review according to PRIMSA guidelines, including case reports and series describing surgical interventions for patients in SE. Cases (157 patients, median age 12.9 years) were followed for a median of 12 months. Patients were in SE for a median of 21 days before undergoing procedures including: focal resection (36.9%), functional hemispherectomy (21%), lobar resection (12.7%), vagus nerve stimulation (VNS) (12.7%), deep brain stimulation (DBS) (6.4%), multiple subpial transection (MST) (3.8%), responsive neurostimulation (RNS) (1.9%), and cortical stimulator placement (1.27%), with 24 patients undergoing multiple procedures. Multiple SE semiologies were identified. 47.8% of patients had focal seizures, and 65% of patients had focal structural abnormalities on MRI. SE persisted for 36.8 ± 47.7 days prior to surgical intervention. SE terminated following surgery in 81.5%, terminated with additional adjuncts in 10.2%, continued in 1.9%, and was not specified in 6.4% of patients. Long-term seizure outcomes were favorable, with the majority improved and 51% seizure-free. Eight patients passed away in follow-up, of which three were in SE. Seizures emerging from one hemisphere were both more likely to immediately terminate (OR 4.7) and lead to long-term seizure-free status (OR 3.9) compared to nonunilateral seizures. No other predictors, including seizure focality, SE duration, or choice of surgical procedure, were predictors of SE termination. Surgical treatment of SE can be effective in terminating SE and leading to sustained seizure freedom, with many different procedures showing efficacy if matched appropriately with SE semiology and etiology. PLAIN LANGUAGE SUMMARY: Patients with persistent seizures (Status Epilepticus) that do not stop following medications can be treated effectively with surgery. Here, we systematically review the entirety of existing literature on surgery for treating status epilepticus to better identify how and when surgery is used and what patients do after surgery.

Epilepsy surgery in adults older than 50 years: A systematic review and meta-analysis

OBJECTIVE

Despite the general safety and efficacy of epilepsy surgery, there is evidence that epilepsy surgery remains underutilized. Although there are an increasing number of studies reporting epilepsy surgery in older adults, there is no consensus on whether epilepsy surgery is efficacious or safe for this population. Our objective was to systematically assess the efficacy as well as safety of resective surgery in people aged 50 years or older with drug-resistant epilepsy.

METHODS

We considered studies that examine the efficacy and safety of epilepsy surgery in adults aged 50 years and older. Study eligibility was limited to studies carried out after 1990, with a minimum of 10 participants and 6 months of follow-up. We searched the following databases for published studies: Ovid MEDLINE, Ovid Embase, Cumulative Index to Nursing and Allied Health Literature, PsychInfo, and Web of Science Conference Proceedings Citation Index - Science. The risk of bias of each included study was independently assessed by two reviewers using the MINORS (Methodological Index for Non-Randomized Studies) instrument.

RESULTS

Eleven case series and 14 cohort studies met the criteria for inclusion, for a total of 1111 older adults who underwent epilepsy surgery along with 4111 adults younger than 50 years as control groups. The pooled cumulative incidence of older adults achieving seizure freedom after resective surgery was 70.1% (95% confidence interval [CI] = 65.3-74.7). There was no evident difference in the incidence of seizure freedom among older adults as compared to younger adults (risk ratio [RR] = 1.05, 95% CI = .97-1.14) in cohort studies. The pooled cumulative incidence of perioperative complications in older adults was 26.2% (95% CI = 21.3-31.7). Among them, 7.5% (95% CI = 5.8-9.5) experienced major complications. Older adults were significantly more at risk of experiencing any complication than younger adults (RR = 2.8, 95% CI = 1.5-5.4).

SIGNIFICANCE

Despite important considerations, epilepsy surgery may be considered appropriate among carefully selected individuals older than 50 years.

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.

Use of Recommended Neurodiagnostic Evaluation Among Patients With Drug-Resistant Epilepsy

Importance

Interdisciplinary practice parameters recommend that patients with drug-resistant epilepsy (DRE) undergo comprehensive neurodiagnostic evaluation, including presurgical assessment. Reporting from specialized centers suggests long delays to referral and underuse of surgery; however, longitudinal data are limited to characterize neurodiagnostic evaluation among patients with DRE in more diverse US settings and populations.

Objective

To examine the rate and factors associated with neurodiagnostic studies and comprehensive evaluation among patients with DRE within 3 US cohorts.

Design, Setting, and Participants

A retrospective cross-sectional study was conducted using the Observational Medical Outcomes Partnership Common Data Model including US multistate Medicaid data, commercial claims data, and Columbia University Medical Center (CUMC) electronic health record data. Patients meeting a validated computable phenotype algorithm for DRE between January 1, 2015, and April 1, 2020, were included. No eligible participants were excluded.

Exposure

Demographic and clinical variables were queried.

Main Outcomes and Measures

The proportion of patients receiving a composite proxy for comprehensive neurodiagnostic evaluation, including (1) magnetic resonance or other advanced brain imaging, (2) video electroencephalography, and (3) neuropsychological evaluation within 2 years of meeting the inclusion criteria.

Results

A total of 33 542 patients with DRE were included in the Medicaid cohort, 22 496 in the commercial insurance cohort, and 2741 in the CUMC database. A total of 31 516 patients (53.6%) were women. The proportion of patients meeting the comprehensive evaluation main outcome in the Medicaid cohort was 4.5% (n = 1520); in the commercial insurance cohort, 8.0% (n = 1796); and in the CUMC cohort, 14.3% (n = 393). Video electroencephalography (24.9% Medicaid, 28.4% commercial, 63.2% CUMC) and magnetic resonance imaging of the brain (35.6% Medicaid, 43.4% commercial, 52.6% CUMC) were performed more regularly than neuropsychological evaluation (13.0% Medicaid, 16.6% commercial, 19.2% CUMC) or advanced imaging (3.2% Medicaid, 5.4% commercial, 13.1% CUMC). Factors independently associated with greater odds of evaluation across all 3 data sets included the number of inpatient and outpatient nonemergency epilepsy visits and focal rather than generalized epilepsy.

Conclusions and Relevance

The findings of this study suggest there is a gap in the use of diagnostic studies to evaluate patients with DRE. Care setting, insurance type, frequency of nonemergency visits, and epilepsy type are all associated with evaluation. A common data model can be used to measure adherence with best practices across a variety of observational data sources.

Specific consistency score for rational selection of epilepsy resection surgery candidates

OBJECTIVE

Degree of indication for epilepsy surgery is determined by taking multiple factors into account. This study aimed to investigate the usefulness of the Specific Consistency Score (SCS), a proposed score for focal epilepsy to rate the indication for epilepsy focal resection.

METHODS

This retrospective cohort study included patients considered for resective epilepsy surgery in Kyoto University Hospital from 2011 to 2022. Plausible epileptic focus was tentatively defined. Cardinal findings were scored based on specificity and consistency with the estimated laterality and lobe. The total points represented SCS. The association between SCS and the following clinical parameters was assessed by univariate and multivariate analysis: (1) probability of undergoing resective epilepsy surgery, (2) good postoperative seizure outcome (Engel I and II or Engel I only), and (3) lobar concordance between the noninvasively estimated focus and intracranial electroencephalographic (EEG) recordings.

RESULTS

A total of 131 patients were evaluated. Univariate analysis revealed higher SCS in the (1) epilepsy surgery group (8.4 [95% confidence interval (CI) = 7.8-8.9] vs. 4.9 [95% CI = 4.3-5.5] points; p < .001), (2) good postoperative seizure outcome group (Engel I and II; 8.7 [95% CI = 8.2-9.3] vs. 6.4 [95% CI = 4.5-8.3] points; p = .008), and (3) patients whose focus defined by intracranial EEG matched the noninvasively estimated focus (8.3 [95% CI = 7.3-9.2] vs. 5.4 [95% CI = 3.5-7.3] points; p = .004). Multivariate analysis revealed areas under the curve of .843, .825, and .881 for Parameters 1, 2, and 3, respectively.

SIGNIFICANCE

SCS provides a reliable index of good indication for resective epilepsy surgery and can be easily available in many institutions not necessarily specializing in epilepsy.

Long-term outcome of treatment-naïve patients with mesial temporal lobe epilepsy with hippocampal sclerosis: A retrospective study in a single center

PURPOSE

This study aimed to describe long-term treatment outcomes of treatment-naïve patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS).

METHODS

A retrospective review was conducted of treatment-naïve patients with MTLE-HS who visited the Yonsei Epilepsy Clinic from April 2000 to April 2022 and were followed up for at least 2 years. Seizure freedom (SF) was defined as no seizures or auras only for >1 year, and complete SF was defined as no seizures including auras for >1 year.

RESULTS

Eighty-four treatment-naïve patients with MTLE-HS with a median follow-up of 122 months were included. Except for one patient who underwent early surgical treatment, of the remaining 83 patients, 31 (37.3 %) achieved SF and remained in remission, 38 (45.8 %) had fluctuations in seizure control, and 14 (16.9 %) never achieved SF. Additionally, 18 (21.7 %) patients achieved complete SF and remained in remission, 42 (50.6 %) showed fluctuations, and 23 (27.7 %) never achieved complete SF. Fifty-three (63.9 %) patients achieved SF and 34 (41.0 %) achieved complete SF at their last visit. Older age at epilepsy onset, male sex, low pretreatment seizure density, history of central nervous system infection before age 5, absence of aura, and fewer antiseizure medications in the final regimen were associated with favorable outcome. Of the 84 patients, 11 (13.1 %) underwent temporal lobectomy.

CONCLUSIONS

Medical treatment outcomes in treatment-naïve MTLE-HS were relatively better than previously reported outcomes in MTLE-HS, although frequent fluctuations in seizure control were observed.

Stereo-electroencephalographic seizure localization in patients with mesial temporal sclerosis: A single center experience

Objective

Epilepsy patients with mesial temporal sclerosis (MTS) on imaging who are drug-resistant usually undergo epilepsy surgery without previous invasive evaluation. However, up to one-third of patients are not seizure-free after surgery. Prior studies have identified risk factors for surgical failure, but it is unclear if they are associated with bilateral or discordant seizure onset.

Methods

In this retrospective case series, we identified 17 epilepsy patients who had MRI-confirmed MTS but received invasive stereo-EEG (SEEG) evaluation before definitive intervention. We analyzed their presurgical risk factors in relation to SEEG seizure onset localization and MRI/SEEG concordance.

Results

SEEG ictal onset was concordant with MTS localization (i.e. seizures started only from the hippocampus with MTS) in 5 out of 13 patients with unilateral MTS (UMTS) and in 3 out of 4 patients with bilateral MTS.No statistically significant association regarding concordance of SEEG ictal onset and MTS location was found in patients with such risk factors as a history of non-mesial temporal aura, frequent focal to bilateral tonic-clonic seizures, prior viral brain infection, or family history of epilepsy. Nine out of 13 UMTS patients had resective surgery only, 5 out of 9 (56 %) have Engel class I outcome at most recent follow-up (median 46.5 months, range 22-91 months). In Engel class I cohort, the SEEG ictal onset was concordant with MTS location in 3 out of 5 patients, and 2 patients had ipsilateral temporal neocortical ictal onset.

Conclusions

Our findings suggest that patients with MTS might have discordant SEEG ictal onset (in 61.5% patients with UMTS in presented cohort), which may explain poor surgical outcome after destructive surgery in these cases.

Significance

Although no statistically significant association was found in this under-powered study, these findings could be potentially valuable for future meta-analyses.

Combining OPM and lesion mapping data for epilepsy surgery planning: a simulation study

When planning for epilepsy surgery, multiple potential sites for resection may be identified through anatomical imaging. Magnetoencephalography (MEG) using optically pumped sensors (OP-MEG) is a non-invasive functional neuroimaging technique which could be used to help identify the epileptogenic zone from these candidate regions. Here we test the utility of a-priori information from anatomical imaging for differentiating potential lesion sites with OP-MEG. We investigate a number of scenarios: whether to use rigid or flexible sensor arrays, with or without a-priori source information and with or without source modelling errors. We simulated OP-MEG recordings for 1309 potential lesion sites identified from anatomical images in the Multi-centre Epilepsy Lesion Detection (MELD) project. To localise the simulated data, we used three source inversion schemes: unconstrained, prior source locations at centre of the candidate sites, and prior source locations within a volume around the lesion location. We found that prior knowledge of the candidate lesion zones made the inversion robust to errors in sensor gain, orientation and even location. When the reconstruction was too highly restricted and the source assumptions were inaccurate, the utility of this a-priori information was undermined. Overall, we found that constraining the reconstruction to the region including and around the participant's potential lesion sites provided the best compromise of robustness against modelling or measurement error.

An Applied Anatomic Guide to Anterior Temporal Lobectomy and Amygdalohippocampectomy: Laboratory Cranial and White Matter Dissections to Inform Surgical Practice

BACKGROUND AND OBJECTIVES

Anterior temporal lobectomy and amygdalohippocampectomy is a challenging procedure because of the deep surgical trajectory and complex regional neurovascular anatomy. A thorough knowledge of the involved anatomic structures is crucial for a safe and effective procedure. Our objective is to explore the white matter pathways in or around the operative corridor and to illuminate the 3-dimensional relationships of the pertinent operative parenchymal and skull base anatomy, aiming to inform and simplify surgical practice.

METHODS

Four normal, adult, cadaveric, formalin-fixed cerebral hemispheres (2 left and 2 right) treated with the Klinger's technique and 2 formalin-fixed and colored-latex-injected cadaveric heads (4 sides) were used. Focused white matter and cadaveric dissections were used to study the relevant anatomy implicated during an anterior temporal lobectomy. Four illustrative cases were also included. Digital photographs from every dissection step were obtained.

RESULTS

Major white matter pathways that are inevitably traversed during the approach are the inferior longitudinal fasciculus, uncinate fasciculus, and inferior arm of the cingulum. Tracts that can be potentially injured, should the dissection plane tilt inadvertently superiorly or posteriorly, are the inferior fronto-occipital fasciculus, Meyer's loop, superior longitudinal fasciculus/arcuate fasciculus complex, and basal ganglia. Consistent cranial and parenchymal landmarks that can act as a roadmap during the procedure are recorded and paired with their intraoperative equivalent to provide a thorough, yet simple, stepwise guide for the surgeon.

CONCLUSION

White matter dissections, cadaveric cranial dissections, and intraoperative images are put together to provide a simplified stepwise surgical manual for anterior temporal lobectomy. Laboratory investigations that focus on the intricate 3-dimensional relationships of the pertinent operative anatomy from the surgeon's eye may enrich anatomic knowledge and push surgical boundaries, to minimize complication rates and ultimately improve patient outcomes.

Suppression of absence seizures by using different stimulations in a reduced corticothalamic-basal ganglion-pedunculopontine nucleus model

Coupled neural network models are playing an increasingly important part in the modulation of absence seizures today. However, it is currently unclear how basal ganglia, corticothalamic network and pedunculopontine nucleus can coordinate with each other to develop a whole coupling circuit, theoretically. In addition, it is still difficult to select effective parameters of electrical stimulation on the regulation of absence seizures in clinical trials. Therefore, to develop a coupled model and reduce computation cost, a new model constructed by a simplified basal ganglion, two corticothalamic circuits and a pedunculopontine nucleus was proposed. Further, to seek better inhibition therapy, three electrical stimulations, high frequency stimulation (HFS), 1:0 coordinate reset stimulation (CRS) and 3:2 CRS, were applied to the thalamic reticular nucleus (RE) in the first corticothalamic circuit in the coupled model. The simulation results revealed that increasing the frequency and pulse width of an electrical stimulation within a certain range can also suppress seizures. Under the same parameters of electrical stimulation, the inhibitory effect of HFS on seizures was better than that of 1:0 CRS and 3:2 CRS. The research established a reduced corticothalamic-basal ganglion-pedunculopontine nucleus model, which lays a theoretical foundation for future optimal parameters selection of electrical stimulation. We hope that the findings will provide new insights into the role of theoretical models in absence seizures.

Long-term outcomes of mesial temporal laser interstitial thermal therapy for drug-resistant epilepsy and subsequent surgery for seizure recurrence: a multi-centre cohort study

BACKGROUND

Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive alternative to surgical resection for drug-resistant mesial temporal lobe epilepsy (mTLE). Reported rates of seizure freedom are variable and long-term durability is largely unproven. Anterior temporal lobectomy (ATL) remains an option for patients with MRgLITT treatment failure. However, the safety and efficacy of this staged strategy is unknown.

METHODS

This multicentre, retrospective cohort study included 268 patients consecutively treated with mesial temporal MRgLITT at 11 centres between 2012 and 2018. Seizure outcomes and complications of MRgLITT and any subsequent surgery are reported. Predictive value of preoperative variables for seizure outcome was assessed.

RESULTS

Engel I seizure freedom was achieved in 55.8% (149/267) at 1 year, 52.5% (126/240) at 2 years and 49.3% (132/268) at the last follow-up ≥1 year (median 47 months). Engel I or II outcomes were achieved in 74.2% (198/267) at 1 year, 75.0% (180/240) at 2 years and 66.0% (177/268) at the last follow-up. Preoperative focal to bilateral tonic-clonic seizures were independently associated with seizure recurrence. Among patients with seizure recurrence, 14/21 (66.7%) became seizure-free after subsequent ATL and 5/10 (50%) after repeat MRgLITT at last follow-up≥1 year.

CONCLUSIONS

MRgLITT is a viable treatment with durable outcomes for patients with drug-resistant mTLE evaluated at a comprehensive epilepsy centre. Although seizure freedom rates were lower than reported with ATL, this series represents the early experience of each centre and a heterogeneous cohort. ATL remains a safe and effective treatment for well-selected patients who fail MRgLITT.

Progress in TLE treatment from 2003 to 2023: scientific measurement and visual analysis based on CiteSpace

Objective

Temporal lobe epilepsy (TLE) is the most common cause of drug-resistant epilepsy and can be treated surgically to control seizures. In this study, we analyzed the relevant research literature in the field of temporal lobe epilepsy (TLE) treatment to understand the background, hotspots, and trends in TLE treatment research.

Methods

We discussed the trend, frontier, and hotspot of scientific output in TLE treatment research in the world in the last 20 years by searching the core collection of the Web of Science database. Excel and CiteSpace software were used to analyze the basic data of the literature.

Result

We identified a total of 2,051 publications on TLE treatment from 75 countries between 2003 and 2023. We found that the publication rate was generally increasing. The United States was the most publishing country; among the research institutions on TLE treatment, the University of California system published the most relevant literature and collaborated the most with other institutions. The co-citation of literature, keyword co-occurrence, and its clustering analysis showed that the early studies focused on open surgical treatment, mainly by lobectomy. In recent years, the attention given to stereotactic, microsurgery, and other surgical techniques has gradually increased, and the burst analysis indicated that new research hotspots may appear in the future in the areas of improved surgical procedures and mechanism research.

Comparing vagus nerve stimulation and resective surgery outcomes in patients with co-occurring autism and epilepsy to patients with epilepsy alone: A population-based study

Autism and epilepsy commonly co-occur. Understanding trends in healthcare utilization and in-hospital outcomes amongst patients with autism and epilepsy can help optimize care and reduce costs. We compared hospital outcomes amongst patients with autism and epilepsy to those with epilepsy alone undergoing vagus nerve stimulation (VNS) and resective/disconnective surgery. Differences in discharge status, in-hospital mortality, mean length of stay (LOS), cost and surgical/medical complications were examined. Elective surgical admissions amongst patients with epilepsy alone and co-occurring autism and epilepsy were identified in the 2003-14 National Inpatient Sample (NIS) using previously validated ICD-9-CM case definitions. One patient with co-occurring epilepsy and autism was matched to three epilepsy patients for age, sex and (1) VNS and (2) resective/disconnective surgery. Multinomial logistic regressions were performed to examine the outcomes of interest. Data were collected on: (1) VNS-52 (mean age: 12.79 ± 1.03; 19.27% female) hospital admissions in persons with comorbid autism and epilepsy, 156 (mean age: 12.84 ± 0.71; 19.31% female) matched controls with epilepsy alone; (2) resective/disconnective surgery-113 (mean age: 12.99 ± 0.84; 24.55% female) with comorbid autism and epilepsy, 339 (mean age: 13.37 ± 0.68; 23.86% female) matched controls with epilepsy alone. Compared to patients with epilepsy alone, patients with autism and epilepsy who underwent either surgery showed no differences for in-hospital mortality, discharge status, mean LOS, hospitalization cost, and surgical/medical complications. Our study shows the feasibility and safety of epilepsy VNS and resective surgery in those with ASD do not differ with those with epilepsy alone, contrary to the prevalent safety concerns of epilepsy surgery in patients with ASD.

Epilepsy associated with cerebral cavernous malformations managed with stereotactic radiosurgery: an international, multicenter study

OBJECTIVE

Stereotactic radiosurgery (SRS) has been proposed as an alternative to resection for epilepsy control in patients with cerebral cavernous malformations (CCM) located in critical areas.

METHODS

This multicentric, retrospective study evaluated seizure control in patients with a solitary CCM and a history of at least one seizure prior to SRS.

RESULTS

109 patients (median age at diagnosis 28.9 years, interquartile range (IQR) 16.4 years] were included. Prior to SRS, 2 (1.8%) were seizure-free without medication, 35 (32.1%) were seizure-free with antiseizure medications (ASM), 17 (15.6%) experienced an improvement of at least 50% in seizure frequency/intensity with ASM, and 55 (50.5%) experienced an improvement of less than 50% in seizure frequency/intensity with ASM. At a median follow-up of 3.5 years post-SRS (IQR: 4.9), 52 (47.7%) patients were Engel class I, 13 (11.9%) class II, 17 (15.6%) class III, 22 (20.2%) class IVA or IVB and 5 (4.6%) class IVC. For the 72 patients who had seizures despite medication prior to SRS, a delay > 1.5 years between epilepsy presentation and SRS decreased the probability to become seizure-free, HR 0.25 (95% CI 0.09-0.66), p = 0.006. The probability of achieving Engel I at the last follow-up was 23.6 (95% CI 12.7-33.1) and 31.3% (95% CI 19.3-50.8) at 2 and 5 years respectively. 27 patients were considered as having drug-resistant epilepsy. At a median follow-up of 3.1 years (IQR: 4.7), 6 (22.2%) of them were Engel I, 3 (11.1%) Engel II, 7 (25.9%) Engel III, 8 (29.6%) Engel IVA or IVB and 3 (11.1%) Engel IVC.

INTERPRETATION

47.7% of patients managed with SRS for solitary CCM presenting with seizures achieved Engel class I at the last follow-up.

Increasing challenges to trial recruitment and conduct over time

OBJECTIVE

This study was undertaken to evaluate how the challenges in the recruitment and retention of participants in clinical trials for focal onset epilepsy have changed over time.

METHODS

In this systematic analysis of randomized clinical trials of adjunct antiseizure medications for medication-resistant focal onset epilepsy, we evaluated how the numbers of participants, sites, and countries have changed since the first such trial in 1990. We also evaluated the proportion of participants who completed each trial phase and their reasons for early trial exit. We analyzed these trends using mixed effects generalized linear models accounting for the influence of the number of trial sites and trial-specific variability.

RESULTS

The number of participants per site has steadily decreased over decades, with recent trials recruiting fewer than five participants per site (reduction by .16 participants/site/year, p < .0001). Fewer participants also progressed from recruitment to randomization over time (odds ratio = .94/year, p = .014). Concurrently, there has been an increase in the placebo response over time (increase in median percent reduction of .4%/year, p = .02; odds ratio of increase in 50% responder rate of 1.03/year, p = .02), which was not directly associated with the number of sites per trial (p > .20).

SIGNIFICANCE

This historical analysis highlights the increasing challenges with participant recruitment and retention, as well as increasing placebo response. It serves as a call to action to change clinical trial design to address these challenges.

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.

Evaluating the concordance of functional MRI-based language lateralization and Wada testing in epilepsy patients: A single-center analysis

BACKGROUND

For patients with drug-resistant epilepsy, surgery may be effective in controlling their disease. Surgical evaluation may involve localization of the language areas using functional magnetic resonance imaging (fMRI) or Wada testing. We evaluated the accuracy of task-based fMRI versus Wada-based language lateralization in a cohort of our epilepsy patients.

METHODS

In a single-center, retrospective analysis, we identified patients with medically intractable epilepsy who participated in presurgical language mapping (n = 35) with fMRI and Wada testing. Demographic variables and imaging metrics were obtained. We calculated the laterality index (LI) from task-evoked fMRI activation maps across language areas during auditory and reading tasks to determine lateralization. Possible scores for LI range from -1 (strongly left-hemisphere dominant) to 1 (strongly right-hemisphere dominant). Concordance between fMRI and Wada was estimated using Cohen's Kappa coefficient. Association between the LI scores from the auditory and reading tasks was tested using Spearman's rank correlation coefficient.

RESULTS

The fMRI-based laterality indices were concordant with results from Wada testing in 91.4% of patients during the reading task (κ = .55) and 96.9% of patients during the auditory task (κ = .79). The mean LIs for the reading and auditory tasks were -0.52 ± 0.43 and -0.68 ± 0.42, respectively. The LI scores for the language and reading tasks were strongly correlated, r(30) = 0.57 (p = 0.001).

CONCLUSION

Our findings suggest that fMRI is generally an accurate, low-risk alternative to Wada testing for language lateralization. However, when fMRI indicates atypical language lateralization (e.g., bilateral dominance), patients may benefit from subsequent Wada testing or intraoperative language mapping.

Neurosurgical management of elevated tone in childhood: interventions, indications and uncertainties

Elevated tone (hypertonia) is a common problem in children with physical disabilities. Medications intended to reduce tone often have limited efficacy, with use further limited by a significant side effect profile. Consequently, there has been growing interest in the application of Neurosurgical Interventions for the Management of Posture and Tone (NIMPTs). Three main procedures are now commonly used: selective dorsal rhizotomy (SDR), intrathecal baclofen (ITB) and deep brain stimulation (DBS). This review compares these interventions, along with discussion on the potential role of lesioning surgery. These interventions variably target spasticity and dystonia, acting at different points in the distributed motor network. SDR, an intervention for reducing spasticity, is most widely used in carefully selected ambulant children with cerebral palsy. ITB is more commonly used for children with more severe disability, typically non-ambulant, and can improve both dystonia and spasticity. DBS is an intervention which may improve dystonia. In children with certain forms of genetic dystonia DBS may dramatically improve dystonia. For other causes of dystonia, and in particular dystonia due to acquired brain injury, improvements following surgery are more modest and variable. These three interventions vary in terms of their side-effect profile and reversibility. There are currently populations of children for who it is unclear which intervention should be considered (SDR vs ITB, or ITB vs DBS). Concerns have been raised as to the equity of access to NIMPTs for children across the UK, and whether the number of surgeries performed each year meets the clinical need.

Personalized dynamic network models of the human brain as a future tool for planning and optimizing epilepsy therapy

Epilepsy is a common neurological disorder, with one third of patients not responding to currently available antiepileptic drugs. The proportion of pharmacoresistant epilepsies has remained unchanged for many decades. To cure epilepsy and control seizures requires a paradigm shift in the development of new approaches to epilepsy diagnosis and treatment. Contemporary medicine has benefited from the exponential growth of computational modeling, and the application of network dynamics theory to understanding and treating human brain disorders. In epilepsy, the introduction of these approaches has led to personalized epileptic network modeling that can explore the patient's seizure genesis and predict the functional impact of resection on its individual network's propensity to seize. The application of the dynamic systems approach to neurostimulation therapy of epilepsy allows designing stimulation strategies that consider the patient's seizure dynamics and long-term fluctuations in the stability of their epileptic networks. In this article, we review, in a nontechnical fashion suitable for a broad neuroscientific audience, recent progress in personalized dynamic brain network modeling that is shaping the future approach to the diagnosis and treatment of epilepsy.

Predictors of referral for long-term EEG monitoring for Medicare beneficiaries with drug-resistant epilepsy

OBJECTIVE

For people with drug-resistant epilepsy, the use of epilepsy surgery is low despite favorable odds of seizure freedom. To better understand surgery utilization, we explored factors associated with inpatient long-term EEG monitoring (LTM), the first step of the presurgical pathway.

METHODS

Using 2001-2018 Medicare files, we identified patients with incident drug-resistant epilepsy using validated criteria of ≥2 distinct antiseizure medication (ASM) prescriptions and ≥1 drug-resistant epilepsy encounter among patients with ≥2 years pre- and ≥1 year post-diagnosis Medicare enrollment. We used multilevel logistic regression to evaluate associations between LTM and patient, provider, and geographic factors. We then analyzed neurologist-diagnosed patients to further evaluate provider/environmental characteristics.

RESULTS

Of 12 044 patients with incident drug-resistant epilepsy diagnosis identified, 2% underwent surgery. Most (68%) were diagnosed by a neurologist. In total, 19% underwent LTM near/after drug-resistant epilepsy diagnosis; another 4% only underwent LTM much prior to diagnosis. Patient factors most strongly predicting LTM were age <65 (adjusted odds ratio 1.5 [95% confidence interval 1.3-1.8]), focal epilepsy (1.6 [1.4-1.9]), psychogenic non-epileptic spells diagnosis (1.6 [1.1-2.5]) prior hospitalization (1.7, [1.5-2]), and epilepsy center proximity (1.6 [1.3-1.9]). Additional predictors included female gender, Medicare/Medicaid non-dual eligibility, certain comorbidities, physician specialties, regional neurologist density, and prior LTM. Among neurologist-diagnosed patients, neurologist <10 years from graduation, near an epilepsy center, or epilepsy-specialized increased LTM likelihood (1.5 [1.3-1.9], 2.1 [1.8-2.5], 2.6 [2.1-3.1], respectively). In this model, 37% of variation in LTM completion near/after diagnosis was explained by individual neurologist practice and/or environment rather than measurable patient factors (intraclass correlation coefficient 0.37).

SIGNIFICANCE

A small proportion of Medicare beneficiaries with drug-resistant epilepsy completed LTM, a proxy for epilepsy surgery referral. While some patient factors and access measures predicted LTM, non-patient factors explained a sizable proportion of variance in LTM completion. To increase surgery utilization, these data suggest initiatives targeting better support of neurologist referral.

Aromatherapy for the brain: Lavender's healing effect on epilepsy, depression, anxiety, migraine, and Alzheimer's disease: A review article

Neurological diseases affect the nervous system, including the brain, spinal cord, cranial nerves, nerve roots, autonomic nervous system, neuromuscular junctions, and muscles. Herbal medicine has long been used to cure these diseases. One of these plants is lavender, which is composed of various compounds, including terpenes, such as linalool, limonene, triterpenes, linalyl acetate, alcohols, ketones, polyphenols, coumarins, cineole, and flavonoids. In this review, the literature was searched using scientific search engines and databases (Google Scholar, Science Direct, Scopus, and PubMed) for papers published between 1982 and 2020 via keywords, including review, lavender, and neurological disorders. This plant exerts its healing effect on many diseases, such as anxiety and depression through an inhibitory effect on GABA. The anti-inflammatory effects of this plant have also been documented. It improves depression by regulating glutamate receptors and inhibiting calcium channels and serotonergic factors, such as SERT. Its antiepileptic mechanism is due to an increase in the inhibitory effect of GABA and potassium current and a decrease in sodium current. Therefore, many vegetable oils are also used in herbal medicine. In this review, the healing effect of lavender on several neurological disorders, including epilepsy, depression, anxiety, migraine, and Alzheimer's disease was investigated. All findings strongly support the traditional uses of lavender. More clinical studies are needed to investigate the effect of the plants' pharmacological active constituents on the treatment of life-threatening diseases in humans. The limitations of this study are the low quality and the limited number of clinical studies. Different administration methods of lavender are one of the limitations of this review.

Drug-Inducible Gene Therapy Effectively Reduces Spontaneous Seizures in Kindled Rats but Creates Off-Target Side Effects in Inhibitory Neurons

Over a third of patients with temporal lobe epilepsy (TLE) are not effectively treated with current anti-seizure drugs, spurring the development of gene therapies. The injection of adeno-associated viral vectors (AAV) into the brain has been shown to be a safe and viable approach. However, to date, AAV expression of therapeutic genes has not been regulated. Moreover, a common property of antiepileptic drugs is a narrow therapeutic window between seizure control and side effects. Therefore, a long-term goal is to develop drug-inducible gene therapies that can be regulated by clinically relevant drugs. In this study, a first-generation doxycycline-regulated gene therapy that delivered an engineered version of the leak potassium channel Kcnk2 (TREK-M) was injected into the hippocampus of male rats. Rats were electrically stimulated until kindled. EEG was monitored 24/7. Electrical kindling revealed an important side effect, as even low expression of TREK M in the absence of doxycycline was sufficient to cause rats to develop spontaneous recurring seizures. Treating the epileptic rats with doxycycline successfully reduced spontaneous seizures. Localization studies of infected neurons suggest seizures were caused by expression in GABAergic inhibitory neurons. In contrast, doxycycline increased the expression of TREK-M in excitatory neurons, thereby reducing seizures through net inhibition of firing. These studies demonstrate that drug-inducible gene therapies are effective in reducing spontaneous seizures and highlight the importance of testing for side effects with pro-epileptic stressors such as electrical kindling. These studies also show the importance of evaluating the location and spread of AAV-based gene therapies in preclinical studies.

Surgical treatment of epilepsy - Initial experience from a comprehensive epilepsy program in coastal South India

Objectives

The objectives of this study were to share our initial experience with epilepsy surgery and provide an overview on the surgical treatments of epilepsies.

Materials and Methods

This was a retrospective analysis of the demographics and clinical and investigative features of patients who underwent epilepsy surgery between January 2016 and August 2021. Postoperative seizure outcome was categorized according to modified Engel's classification, and the minimum period of follow-up was 1 year.

Results

The study group included 30 patients with an age ranging from 6 years to 45 years (mean: 22.28 years, median: 20 years) and a male: female ratio of 20:10. The epilepsy duration before surgery ranged from 3 years to 32 years (median: 7 years). Majority of our patients underwent resective surgeries (28/30 = 93.3%), and disconnection procedures were done in two patients. This included one functional hemispherotomy and one posterior quadrantic disconnection. Temporal lobe resective surgery was the most common procedure (16/30 = 53.3%), followed by eight frontal lobe and two parietal lobe surgeries. Among resective surgeries, majority were lesional surgeries and the pathologies included mesial temporal sclerosis (4), dysembryoplastic neuroepithelial tumor (8), ganglioglioma (6), cavernoma (4), focal cortical dysplasia (2), gliosis (1), and one case of hypothalamic hamartoma. Intraoperative electrocorticography was used in all cases for optimizing surgical resection/disconnection. Nearly two-thirds of our patients (66.6%) had an Engel's Class I outcome, five patients had Engel's Class II outcome, three patients had Class III outcome, and one patient did not have any worthwhile improvement. Temporal lobe surgery patients had a better seizure outcome compared to extratemporal surgeries (84% vs. 74%). Overall, complications were minimal and short lasting, and comprised meningitis in three patients (5.6%) and transient worsening of hemiparesis following hemispherotomy in two patients. There was no mortality or long-lasting major morbidity in our patients.

Conclusion

In carefully selected patients with drug-resistant epilepsy, surgery offers an excellent chance of becoming seizure-free with significant improvement in overall quality of life. Majority of the common epilepsy surgery procedures can be performed through a multidisciplinary approach even in centers with limited resources.

Lesional Epilepsy in Children: Removing Doubt to Cut It Out

Prevalence and Risk Factors for Pharmacoresistance in Children With Focal Cortical Dysplasia-Related Epilepsy Cohen NT, Chang P, You X, Zhang A, Havens KA, Oluigbo CO, Whitehead MT, Gholipour T, Gaillard WD. Neurology . 2022;99(18):e2006-e2013. doi:10.1212/WNL.0000000000201033 Background and objectives: Focal cortical dysplasia is the most common cause of surgically-remediable epilepsy in children. Little is known about the risk factors for the timing and development of pharmacoresistance in this population. This study sought to evaluate the prevalence and risk factors for pharmacoresistance in pediatric FCD-related epilepsy. Methods: In this retrospective single-center cohort design, patients were identified from search of centralized radiology report database and a central epilepsy surgical database. Inclusion criteria consisted of: 3T MRI-confirmed FCD from January, 2011 to January, 2020; ages 0 days to 22 years at MRI; at least 18 months of documented follow-up after MRI, unless had single seizure or incidentally discovered FCD. Records were excluded if there was dual pathology (except for mesial temporal sclerosis), hemimegalencephaly, or tuberous sclerosis complex present in imaging or history. Results: One hundred forty-three patients with confirmed FCD met inclusion criteria. One hundred twenty-four children had epilepsy (87% of FCD patients) with median age of seizure onset 2.7 years (IQR 0.75-6 years, range 0 to 17 years). Twelve children (8.5%) had a single lifetime seizure (provoked or unprovoked) or recurrent provoked seizures. Seven children (4.9%) had incidental FCD. Ninety-two patients (74%) of those with epilepsy met criteria for pharmacoresistance. Of children with epilepsy of all types, 93 children (75%) were seizure-free at the last visit. Eighty-two patients underwent epilepsy surgery, of whom 59 (72%) achieved seizure freedom. 7% (9/124) achieved seizure freedom with a second ASM, and 5.6% (7/124) with a third or more ASMs. Failure of only one antiseizure medication is associated with enormous increased incidence and earlier development of pharmacoresistance (OR 346, 95% CI 19.6-6100). Cox regression showed FCD lobar location, pathologic subtype, and age of seizure onset are not. Conclusions: Failure of one antiseizure medication is associated with substantial risk of pharmacoresistance. These data support an operational re-definition of pharmacoresistance, for surgical planning, in FCD-related epilepsy to the failure of one antiseizure medication, and support early, potentially curative surgery to improve outcomes in this patient population.

Seizure in geriatric population - An unheeded integer

BACKGROUND

Epilepsy is one of the most prevalent neurological conditions among the elderly. Age-related epileptogenic disorders as well as the ageing itself pose a risk for seizures in the elderly. The lack of witnesses, non-specific symptoms, and transient symptoms make the diagnosis challenging in the elderly.

AIM

This study aimed to assess the various presentation and aetiology for the seizure disorder in the elderly population.

MATERIALS AND METHODS

A total of 125 elderly patients ≥60 years with new onset seizure were included in the study. Demographic data, co-morbidities, and clinical presentation of seizure were elicited. Hemogram, liver and renal function tests, random blood sugar, electrolytes, and serum calcium were analysed. Computed tomography (CT), magnetic resonance imaging (MRI) brain, and electroencephalogram (EEG) were performed.

RESULTS

Seizure was seen predominantly in the males with age group of 60-70 years. Generalized tonic-clonic seizure was the commonest presentation, followed by focal seizures. The leading causes of seizures were cerebral vascular accidents, metabolic conditions, and alcohol. CT brain was abnormal in 49%, and 73% of the patients showed abnormality in MRI brain. EEG was abnormal in 17.3% of patients. Temporal lobe infarction was the commonest, trailed by parieto-temporal and frontal lobe involvement.

CONCLUSION

Seizures in the elderly have varied clinical signs and aetiology. An awareness about these atypical presentation and aetiology is essential for the early diagnosis and management to prevent morbidity.

Number of epilepsy surgeries has decreased despite an increase in pre-surgical evaluations at a tertiary pediatric epilepsy center in Ontario

OBJECTIVE

A recent U.S. study reported that the number of epilepsy surgeries has remained stable or declined in recent years despite an increase in pre-surgical evaluation. This study aimed to evaluate trends in pre-surgical evaluation and epilepsy surgery from 2001 to 2019 and to determine whether these trends have changed in the later period (2014-2019) compared to earlier period (2001-2013).

METHODS

This study evaluated trends in pre-surgical evaluation and epilepsy surgery at a tertiary pediatric epilepsy center. Children with drug resistant epilepsy who were evaluated for surgery were included. Clinical data, reasons for not undergoing surgery, and surgical characteristics of surgery patients were collected. Overall trends and trends in later period compared to earlier period for pre-surgical evaluation and epilepsy surgery were assessed.

RESULTS

There were 1151 children who were evaluated for epilepsy surgery and 546 underwent surgery. There was an upward trend in pre-surgical evaluation in the earlier period (rate ratio [RR]=1.04 (95%CI:1.02-1.07), p<0.001) and the trajectory of presurgical evaluation in the later period was not significantly different to the earlier period (RR=1.00 [95%CI:0.95-1.06], p = 0.88). Among the reasons for not undergoing surgery, failure to localize the seizures occurred more frequently in later period than earlier period (22.6% vs. 17.1% respectively, p = 0.024). For number of surgeries, there was an upward trend between 2001 and 2013 (RR=1.08 [95%CI:1.05-1.11], p<0.001), and a decreasing trend in the later period compared to earlier period (RR=0.91 [95%CI:0.84-0.99], p = 0.029).

CONCLUSION

Despite an increasing trend in pre-surgical evaluation, there was a decreasing trend in the number of epilepsy surgery in the later period as there was a larger proportion of patients in whom the seizures could not be localized. Trends in presurgical evaluation and epilepsy surgery will continue to evolve with introduction of technologies such as stereo-EEG and minimally invasive laser therapy.

The influence of disease course and surgery on quality of life in children with focal cortical dysplasia and long-term epilepsy-associated tumours: A systematic review and meta-analysis

INTRODUCTION

Carefully selected patients with lesional epilepsy, including focal cortical dysplasia (FCD) and long-term epilepsy-associated tumours (LEAT), can benefit from epilepsy surgery. The influence of disease course and subsequent epilepsy surgery on quality of life (QoL) and intelligence quotient (IQ) is not well understood.

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies reporting QoL or IQ measures in paediatric patients with FCD and LEAT at epilepsy onset, at establishment of drug resistance (pre-operative/non-surgically managed) and post-operatively were included. To evaluate the "effect size" and clinical significance of surgery, a meta-analysis of the data was conducted using fixed effects models for weighted mean differences, 95% confidence intervals and sensitivity analyses.

RESULTS

Nineteen eligible studies (911 patients) were included, 17 assessing IQ and 2 evaluating QoL. Twelve studies reported preoperative and postoperative IQ measures and five reported IQ in non-surgically managed cohorts after drug resistance was established; no papers reported IQ at epilepsy onset. No significant IQ/DQ changes were detected after surgery (pre-operative pooled mean 69.32; post-operative pooled mean 69.98; p = 0.32). Age at epilepsy surgery, type of surgery and epilepsy-related pathology did not influence the post-operative IQ. QoL was reported in 2 studies with the pooled mean estimates for pre- and post-operative QoL being 42.52 and 55.50, respectively.

CONCLUSIONS

The present study demonstrated no statistical change in IQ and QoL following surgery in paediatric patients with FCD and LEAT. There was no data on IQ and QoL at disease onset. Attempting to understand the impact of epilepsy, ongoing seizures and surgery on IQ and QoL will facilitate planning of future studies that aim to optimise quality of life and developmental outcomes in these children. Studies assessing children at epilepsy onset with longitudinal follow-up are required to optimise the timing of epilepsy surgery on QoL and IQ.

Withdrawal of antiseizure medications - for whom, when, and how?

INTRODUCTION

Epilepsy is a chronic disorder of the brain characterized by an enduring predisposition to generate epileptic seizures. Most patients can achieve complete seizure control (seizure freedom) with antiseizure medications (ASMs). In some of them, the withdrawal of ASMs can be considered. Guidance is required to identify patients in whom drug discontinuation can be safely attempted and to inform when and how ASM withdrawal can be done.

AREAS COVERED

In this perspective, the authors discuss the evidence on ASM withdrawal in epilepsy patients who are seizure-free and provide some suggestions on how to do it effectively in clinical practice, minimizing the risk of seizure recurrence.

EXPERT OPINION

The decision of discontinuing ASMs in epilepsy patients should rely on an accurate estimate of seizure recurrence risk. Whenever possible, such a risk should be assessed on an individual basis. The decision should also consider the psychosocial and personal consequences of seizure relapse. No robust evidence is available on the safest tapering regimen.