Deciphering the surgical treatment gap for drug-resistant epilepsy (DRE): A literature review

Delays in the diagnosis and surgical treatment of drug-resistant epilepsy: A cohort study

OBJECTIVE

Delay in referral for epilepsy surgery of patients with drug-resistant epilepsy (DRE) is associated with decreased quality of life, worse surgical outcomes, and increased risk of sudden unexplained death in epilepsy (SUDEP). Understanding the potential causes of delays in referral and treatment is crucial for optimizing the referral and treatment process. We evaluated the treatment intervals, demographics, and clinical characteristics of patients referred for surgical evaluation at our level 4 epilepsy center in the U.S. Intermountain West.

METHODS

We retrospectively reviewed the records of patients who underwent surgery for DRE between 2012 and 2022. Data collected included patient demographics, DRE diagnosis date, clinical characteristics, insurance status, distance from epilepsy center, date of surgical evaluation, surgical procedure, and intervals between different stages of evaluation.

RESULTS

Within our cohort of 185 patients with epilepsy (99 female, 53.5%), the mean ± standard deviation (SD) age at surgery was 38.4 ± 11.9 years. In this cohort, 95.7% of patients had received definitive epilepsy surgery (most frequently neuromodulation procedures) and 4.3% had participated in phase 2 intracranial monitoring but had not yet received definitive surgery. The median (1st-3rd quartile) intervals observed were 10.1 (3.8-21.5) years from epilepsy diagnosis to DRE diagnosis, 16.7 (6.5-28.4) years from epilepsy diagnosis to surgery, and 1.4 (0.6-4.0) years from DRE diagnosis to surgery. We observed significantly shorter median times from epilepsy diagnosis to DRE diagnosis (p < .01) and epilepsy diagnosis to surgery (p < .05) in patients who traveled further for treatment. Patients with public health insurance had a significantly longer time from DRE diagnosis to surgery (p < .001).

SIGNIFICANCE

Both shorter distance traveled to our epilepsy center and public health insurance were predictive of delays in diagnosis and treatment intervals. Timely referral of patients with DRE to specialized epilepsy centers for surgery evaluation is crucial, and identifying key factors that may delay referral is paramount to optimizing surgical outcomes.

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

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

Variation in access to specialist services for neurosurgical procedures in adults with epilepsy in England, a cohort study

PURPOSE

To understand if primary consultation at tertiary epilepsy centres (TEC) in England impacts access to neurosurgical procedures (resective surgery, vagus nerve stimulator [VNS], deep brain stimulator [DBS]).

METHODS

Adults with epilepsy, and with a first neurology outpatient visit (index) between 01/01/2013 and 31/12/2015, were followed using English Hospital Episode Statistics from index date to 31/12/2019. Analyses were stratified by geographic location, learning disability record, and whether the index or follow-up visits were at a TEC.

RESULTS

84,093 people were included, with mean 5.5 years of follow-up. 12.4% of the cohort had learning disability (range 10.1%-17.4% across regions). TEC consultations varied by National Health Service regions and Clinical Commissioning Groups. 37.5% of people (11.2%-75.0% across regions) had their index visit at a TEC; and, of those not initially seen at a TEC, 10.6% (6.5%-17.7%) subsequently attended a tertiary centre. During follow-up, 11.1% people (9.5%-13.2%) visited a neurosurgery department, and 2.3% of those (0.9%-5.0%) then underwent a neurosurgical procedure, mainly VNS implantation. Median time from index date to first visit at a neurosurgery centre was 7 months (range 6-8 months across regions) and 40 months to procedure (36.5-49 months, 37.0 months in people with index visit at a TEC and 49.0 months otherwise). People with learning disability were less likely to have resective surgery (<0.5% versus 1.0% in those without) and more likely to undergo VNS implantation (5.8% versus 0.8%).

CONCLUSION

Although clinically recommended for suitable individuals, neurosurgical procedures in epilepsy remain uncommon even after consultation at a TEC. Geographical variation in access to TECs was present.

SEEG study of a rare male temporal lobe epilepsy with orgasmic aura originating from the right amygdala

As a primitive driving force for biological reproduction, sexual behavior (and its associated mechanisms) is extremely complex, and orgasm plays an essential role. The limbic system plays a very important role in regulating human sexual behavior. However, it is not clear which components of the limbic system are related to orgasm sensation. We studied a rare case of spontaneous orgasmic aura in a male patient with temporal lobe epilepsy. Stereoelectroencephalography (SEEG) revealed that the right amygdala was the origin of orgasmic aura. Surgical removal of the medial temporal lobe, including the right amygdala, completely eliminated the patient's seizures. This study demonstrates the critical role of the amygdala in human male orgasm.

Early Identification of Candidates for Epilepsy Surgery: A Multicenter, Machine Learning, Prospective Validation Study

BACKGROUND AND OBJECTIVES

Epilepsy surgery is often delayed. We previously developed machine learning (ML) models to identify candidates for resective epilepsy surgery earlier in the disease course. In this study, we report the prospective validation.

METHODS

In this multicenter, prospective, longitudinal cohort study, random forest models were validated at a pediatric epilepsy center consisting of 2 hospitals and 14 outpatient neurology clinic sites and an adult epilepsy center with 2 hospitals and 27 outpatient neurology clinic sites. The models used neurology visit notes, EEG and MRI reports, visit patterns, hospitalizations, and medication, laboratory, and procedure orders to identify candidates for surgery. The models were trained on historical data up to May 10, 2019. Patients with an ICD-10 diagnosis of epilepsy who visited from May 11, 2019, to May 10, 2020, were screened by the algorithm and assigned surgical candidacy scores. The primary outcome was area under the curve (AUC), which was calculated by comparing scores from patients who underwent epilepsy surgery before November 10, 2020, against scores from nonsurgical patients. Nonsurgical patients' charts were reviewed to determine whether patients with high scores were more likely to be missed surgical candidates. Delay to surgery was defined as the time between the first visit that a surgical candidate was identified by the algorithm and the date of the surgery.

RESULTS

A total of 5,285 pediatric and 5,782 adult patients were included to train the ML algorithms. During the study period, 41 children and 23 adults underwent resective epilepsy surgery. In the pediatric cohort, AUC was 0.91 (95% CI 0.87-0.94), positive predictive value (PPV) was 0.08 (0.05-0.10), and negative predictive value (NPV) was 1.00 (0.99-1.00). In the adult cohort, AUC was 0.91 (0.86-0.97), PPV was 0.07 (0.04-0.11), and NPV was 1.00 (0.99-1.00). The models first identified patients at a median of 2.1 years (interquartile range [IQR]: 1.2-4.9 years, maximum: 11.1 years) before their surgery and 1.3 years (IQR: 0.3-4.0 years, maximum: 10.1 years) before their presurgical evaluations.

DISCUSSION

ML algorithms can identify surgical candidates earlier in the disease course. Even at specialized epilepsy centers, there is room to shorten the time to surgery.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that a machine learning algorithm can accurately distinguish patients with epilepsy who require resective surgery from those who do not.

NLP-based tools for localization of the epileptogenic zone in patients with drug-resistant focal epilepsy

Epilepsy surgery is an option for people with focal onset drug-resistant (DR) seizures but a delayed or incorrect diagnosis of epileptogenic zone (EZ) location limits its efficacy. Seizure semiological manifestations and their chronological appearance contain valuable information on the putative EZ location but their interpretation relies on extensive experience. The aim of our work is to support the localization of EZ in DR patients automatically analyzing the semiological description of seizures contained in video-EEG reports. Our sample is composed of 536 descriptions of seizures extracted from Electronic Medical Records of 122 patients. We devised numerical representations of anamnestic records and seizures descriptions, exploiting Natural Language Processing (NLP) techniques, and used them to feed Machine Learning (ML) models. We performed three binary classification tasks: localizing the EZ in the right or left hemisphere, temporal or extra-temporal, and frontal or posterior regions. Our computational pipeline reached performances above 70% in all tasks. These results show that NLP-based numerical representation combined with ML-based classification models may help in localizing the origin of the seizures relying only on seizures-related semiological text data alone. Accurate early recognition of EZ could enable a more appropriate patient management and a faster access to epilepsy surgery to potential candidates.

Epilepsy monitoring unit practices and safety among NAEC epilepsy centers: A census survey

OBJECTIVE

An epilepsy monitoring unit (EMU) is a specialized unit designed for capturing and characterizing seizures and other paroxysmal events with continuous video electroencephalography (vEEG). Nearly 260 epilepsy centers in the United States are accredited by the National Association of Epilepsy Centers (NAEC) based on adherence to specific clinical standards to improve epilepsy care, safety, and quality. This study examines EMU staffing, safety practices, and reported outcomes.

METHOD

We analyzed NAEC annual report data and results from a supplemental survey specific to EMU practices reported in 2019 from 341 pediatric or adult center directors. Data on staffing, resources, safety practices and complications were collated with epilepsy center characteristics. We summarized using frequency (percentage) for categorical variables and median (inter-quartile range) for continuous variables. We used chi-square or Fisher's exact tests to compare staff responsibilities.

RESULTS

The supplemental survey response rate was 100%. Spell classification (39%) and phase 1 testing (28%) were the most common goals of the 91,069 reported admissions. The goal ratio of EEG technologist to beds of 1:4 was the most common during the day (68%) and off-hours (43%). Compared to residents and fellows, advanced practice providers served more roles in the EMU at level 3 or pediatric-only centers. Status epilepticus (SE) was the most common reported complication (1.6% of admissions), while cardiac arrest occurred in 0.1% of admissions.

SIGNIFICANCE

EMU staffing and safety practices vary across US epilepsy centers. Reported complications in EMUs are rare but could be further reduced, such as with more effective treatment or prevention of SE. These findings have potential implications for improving EMU safety and quality care.

Effect of Race and Insurance Type on Access to, and Outcomes of, Epilepsy Surgery: A Literature Review

BACKGROUND

Despite higher rates of seizure freedom, a large proportion of patients with medically refractory seizures who could benefit from epilepsy surgery do not receive surgical treatment. This literature review describes the association of race and insurance status with epilepsy surgery access and outcomes.

METHODS

Searches in Scopus and PubMed databases related to disparities in epilepsy surgery were conducted. The inclusion criteria consisted of data that could be used to compare epilepsy surgery patient access and outcomes by insurance or race in the United States. Two independent reviewers determined article eligibility.

RESULTS

Of the 289 studies reviewed, 26 were included. Most of the studies were retrospective cohort studies (23 of 26) and national admissions database studies (13 of 26). Of the 17 studies that evaluated epilepsy surgery patient demographics, 11 showed that Black patients were less likely to receive surgery than were White patients or had an increased time to surgery from seizure onset. Nine studies showed that patients with private insurance were more likely to undergo epilepsy surgery and have shorter time to surgery compared with patients with public insurance. No significant association was found between the seizure recurrence rate after surgery with insurance or race.

CONCLUSIONS

Black patients and patients with public insurance are receiving epilepsy surgery at lower rates after a prolonged waiting period compared with other patients with medically refractory epilepsy. These results are consistent across the current reported literature. Future efforts should focus on additional characterization and potential causes of these disparities to develop successful interventions.

Patterns of utilization and cost of healthcare services and pharmacotherapy among patients with drug-resistant epilepsy during the two-year period before neurostimulation: A descriptive analysis of the journey to implantation based on analyses of a large United States healthcare claims database

OBJECTIVE

To conduct a descriptive assessment of patterns of utilization and cost of healthcare services and pharmacotherapies among patients with drug-resistant epilepsy (DRE) before neurostimulator implantation.

METHODS

Using a large United States healthcare claims database, we identified all patients with DRE who were implanted with neurostimulators between January 1, 2012, and December 31, 2019. Patients without an epilepsy diagnosis on their implantation date were excluded, as were those without (1) anti-seizure medication (ASM) dispenses within 12 months of implantation date, and (2) continuous enrollment for the 24-month period before this date. Demographic and clinical characteristics were assessed over the two-year period before implantation, as were patterns of utilization and cost of healthcare services and pharmacotherapy. Care was assessed as all-cause or epilepsy-related, with the latter defined as all medical (inpatient and outpatient) care resulting in diagnoses of epilepsy and all ASM dispenses.

RESULTS

Eight hundred sixty patients met all selection criteria. Among these patients, comorbidities were common, including depression (27%), anxiety (30%), and learning disabilities (25%). Fifty-nine percent of patients had ≥1 all-cause hospitalizations; 57% had ≥1 epilepsy-related admissions. Patients averaged 8.6 epilepsy-related visits to physicians' offices, including 5.1 neurologist visits. Mean all-cause and epilepsy-related healthcare costs during the pre-implantation period were $123,500 and $91,995, respectively; corresponding median values were $74,567 and $53,029. Median monthly all-cause healthcare costs increased by 138% during the 24-month period (from $1,042 to $2,481 in the month prior to implantation); median epilepsy-related costs, by 290% (from $383 to $1,492).

CONCLUSIONS

The two-year period before neurostimulator implantation is a long and costly journey. Estimates likely minimize the burden experienced during this period, given that seizure frequency and severity-and corresponding impacts on quality of life-were unavailable in these data. Further research is needed to understand the clinical, economic, and psychological impact of the time between DRE onset and implantation among qualifying patients.

Characterization and Prediction of Short-term Outcomes in Memory After Temporal Lobe Resection in Children With Epilepsy

BACKGROUND AND OBJECTIVES

The aim of this study was to characterize short-term outcomes in episodic memory, as assessed by the Children's Memory Scale (CMS), after temporal lobe resection in children with epilepsy using empirical methods for assessing cognitive change (i.e., reliable change indices [RCI] and standardized regression-based change scores [SRB]) and develop and internally validate clinically applicable models to predict postoperative memory decline.

METHODS

This retrospective cohort study included children aged 6-16 years who underwent resective epilepsy surgery that included the temporal lobe (temporal only: "temporal" and multilobar: "temporal plus") and who completed preoperative and postoperative neuropsychological assessments including the CMS. Change scores on the CMS delayed memory subtests (Faces, Stories, and Word Pairs) were classified as decline, no change, or improvement using epilepsy-specific RCI and SRB. Logistic regression models for predicting postoperative memory decline were developed and internally validated with bootstrapping.

RESULTS

Of the 126 children included, most of them demonstrated either no significant change (54%-69%) or improvement (8%-14%) in memory performance using RCI on individual measures at a median of 7 months after surgery. A subset of children (23%-33%) showed postoperative declines. Change distributions obtained using RCI and SRB were not statistically significantly different from each other. Preoperative memory test score, surgery side, surgery extent, and preoperative full-scale IQ were predictors of memory decline. Prediction models for memory decline included subsets of these variables with bias-corrected concordance statistics ranging from 0.70 to 0.75. The models were well calibrated although slightly overestimated the probability of verbal memory decline in high-risk patients.

DISCUSSION

This study used empiric methodology to characterize memory outcome in children after temporal lobe resection. Provided online calculator and nomograms may be used by clinicians to estimate the risk of postoperative memory decline for individual patients before surgery.

An Introduction to Minimally Invasive Pediatric Epilepsy Surgery

The field of minimally invasive surgery has evolved over the past 50 years, including neurosurgery, with an evolution to “minimally invasive neurosurgery” when feasible. Epilepsy surgery has followed this trend, with a transition from standard neurosurgical techniques to minimally invasive techniques in all phases of neurosurgical involvement. These include the diagnostic intracranial electroencephalogram with a subdural exploration to stereoelectroencephalography, the actual resection from an open craniotomy to a less destructive technique, or the multiple modalities of neuromodulation instead of a destructive surgery.

The influence of these minimally invasive techniques has resulted in a change in the overall philosophy of pediatric epilepsy surgery. The expectations of what is considered “successful” epilepsy surgery has changed from total seizure control, in other words, a “cure,” to palliative epilepsy surgery with a decrease in the targeted seizures, especially “disabling seizures.” This has led to an overall greater acceptance of epilepsy surgery. This article summarizes the major reasons behind the explosion of minimally invasive pediatric epilepsy surgery, which are amplified in the subsequent articles. Some of this chapter includes the authors' opinions.

Systematic Review and Meta-Analysis of Responsive Neurostimulation in Epilepsy

BACKGROUND

Neuromodulatory implants provide promising alternatives for patients with drug-resistant epilepsy (DRE) in whom resective or ablative surgery is not an option. Responsive neurostimulation (RNS) operates a unique "closed-loop" system of electrocorticography-triggered stimulation for seizure control. A comprehensive review of the current literature would be valuable to guide clinical decision-making regarding RNS.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocols, a systematic PubMed literature review was performed to identify appropriate studies involving patients undergoing RNS for DRE. Full texts of included studies were analyzed and extracted data regarding demographics, seizure reduction rate, responder rate (defined as patients with >50% seizure reduction), and complications were compiled for comprehensive statistical analysis.

RESULTS

A total of 313 studies were screened, and 17 studies were included in the final review, representative of 541 patients. Mean seizure reduction rate was 68% (95% confidence interval 61%-76%), and the mean responder rate was 68% (95% confidence interval 60%-75%). Complications occurred in 102 of 541 patients, for a complication rate of 18.9%. A strong publication bias toward greater seizure reduction rate and increased responder rate was demonstrated among included literature.

CONCLUSIONS

A meta-analysis of recent RNS for DRE literature demonstrates seizure reduction and responder rates comparable with other neuromodulatory implants for epilepsy, demonstrating both the value of this intervention and the need for further research to delineate the optimal patient populations. This analysis also demonstrates a strong publication bias toward positive primary outcomes, highlighting the limitations of current literature. Currently, RNS data are optimistic for the treatment of DRE but should be interpreted cautiously.

Timing of referral to evaluate for epilepsy surgery: Expert Consensus Recommendations from the Surgical Therapies Commission of the International League Against Epilepsy

Epilepsy surgery is the treatment of choice for patients with drug-resistant seizures. A timely evaluation for surgical candidacy can be life-saving for patients who are identified as appropriate surgical candidates, and may also enhance the care of nonsurgical candidates through improvement in diagnosis, optimization of therapy, and treatment of comorbidities. Yet, referral for surgical evaluations is often delayed while palliative options are pursued, with significant adverse consequences due to increased morbidity and mortality associated with intractable epilepsy. The Surgical Therapies Commission of the International League Against Epilepsy (ILAE) sought to address these clinical gaps and clarify when to initiate a surgical evaluation. We conducted a Delphi consensus process with 61 epileptologists, epilepsy neurosurgeons, neurologists, neuropsychiatrists, and neuropsychologists with a median of 22 years in practice, from 28 countries in all six ILAE world regions. After three rounds of Delphi surveys, evaluating 51 unique scenarios, we reached the following Expert Consensus Recommendations: (1) Referral for a surgical evaluation should be offered to every patient with drug-resistant epilepsy (up to 70 years of age), as soon as drug resistance is ascertained, regardless of epilepsy duration, sex, socioeconomic status, seizure type, epilepsy type (including epileptic encephalopathies), localization, and comorbidities (including severe psychiatric comorbidity like psychogenic nonepileptic seizures [PNES] or substance abuse) if patients are cooperative with management; (2) A surgical referral should be considered for older patients with drug-resistant epilepsy who have no surgical contraindication, and for patients (adults and children) who are seizure-free on 1-2 antiseizure medications (ASMs) but have a brain lesion in noneloquent cortex; and (3) referral for surgery should not be offered to patients with active substance abuse who are noncooperative with management. We present the Delphi consensus results leading up to these Expert Consensus Recommendations and discuss the data supporting our conclusions. High level evidence will be required to permit creation of clinical practice guidelines.

Automated Detection and Surgical Planning for Focal Cortical Dysplasia with Multicenter Validation

BACKGROUND

In patients with surgically amenable focal cortical dysplasia (FCD), subtle neuroimaging representation and the risk of open surgery lead to gaps in surgical treatment and delays in surgery.

OBJECTIVE

To construct an integrated platform that can accurately detect FCD and automatically establish trajectory planning for magnetic resonance-guided laser interstitial thermal therapy.

METHODS

This multicenter study included retrospective patients to train the automated detection model, prospective patients for model evaluation, and an additional cohort for construction of the automated trajectory planning algorithm. For automated detection, we evaluated the performance and generalization of the conventional neural network in different multicenter cohorts. For automated trajectory planning, feasibility/noninferiority and safety score were calculated to evaluate the clinical value.

RESULTS

Of the 260 patients screened for eligibility, 202 were finally included. Eighty-eight patients were selected for conventional neural network training, 88 for generalizability testing, and 26 for the establishment of an automated trajectory planning algorithm. The model trained using preprocessed and multimodal neuroimaging displayed the best performance in diagnosing FCD (figure of merit = 0.827 and accuracy range = 75.0%-91.7% across centers). None of the clinical variables had a significant effect on prediction performance. Moreover, the automated trajectory was feasible and noninferior to the manual trajectory (χ2 = 3.540, P = .060) and significantly safer (overall: test statistic = 30.423, P < .001).

CONCLUSION

The integrated platform validated based on multicenter, prospective cohorts exhibited advantages of easy implementation, high performance, and generalizability, thereby indicating its potential in the diagnosis and minimally invasive treatment of FCD.

Treatment gaps in epilepsy

Over 50 million people around the world have epilepsy, and yet, epilepsy recognition and access to care are ongoing issues. Nearly 80% of people with epilepsy live in low-and middle-income countries and face the greatest barriers to quality care. However, there are substantial disparities in care within different communities in high-income countries as well. Across the world, under-recognition of seizures continues to be an issue, leading to diagnostic and treatment delays. This stems from issues surrounding stigma, public education, basic access to care, as well as healthcare worker education. In different regions, people may face language barriers, economic barriers, and technological barriers to timely diagnosis and treatment. Even once diagnosed, people with epilepsy often face gaps in optimal seizure control with the use of antiseizure medications. Additionally, nearly one-third of people with epilepsy may be candidates for epilepsy surgery, and many either do not have access to surgical centers or are not referred for surgical evaluation. Even those who do often experience delays in care. The purpose of this review is to highlight barriers to care for people with epilepsy, including issues surrounding seizure recognition, diagnosis of epilepsy, and the initiation and optimization of treatment.

Underutilization of advanced presurgical studies and high rates of vagus nerve stimulation for drug-resistant epilepsy: a single-center experience and recommendations

INTRODUCTION

Epilepsy surgery continues to be profoundly underutilized despite its safety and effectiveness. We sought to investigate factors that may contribute to this phenomenon, with a particular focus on the antecedent underutilization of appropriate preoperative studies.

METHODS

We reviewed patient data from a pediatric epilepsy clinic over an 18-month period. Patients with drug-resistant epilepsy (DRE) were categorized according to brain magnetic resonance imaging (MRI) findings (lesional, MRI-negative, or multifocal abnormalities) and type of epilepsy diagnosis based on semiology and electroencephalography (EEG) (focal or generalized). We then analyzed the rates of diagnostic test utilization, surgical referral, and subsequent epilepsy surgery as well as vagus nerve stimulation (VNS).

RESULTS

Of the 249 patients with a diagnosis of epilepsy, 138 (55.4%) were found to have DRE. Excluding the 10 patients with DRE who did not undergo MRI, 76 patients (59.4%) were found to be MRI-negative (non-lesional epilepsy), 37 patients (28.9%) were found to have multifocal abnormalities, and 15 patients (11.7%) were found to have a single epileptogenic lesion on MRI (lesional epilepsy). Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) were each completed in nine patients (7.0%) and magnetoencephalography (MEG) in four patients (3.1%). Despite the low utilization rate of adjunctive studies, over half (56.3%) ultimately underwent VNS alone, and 8.6% ultimately underwent definitive intracranial resection or disconnection surgery.

CONCLUSIONS

The underutilization of appropriate non-invasive, presurgical testing in patients with focal DRE may in part explain the continued underutilization of definitive, resective/disconnective surgery. For patients without access to a high-volume, multidisciplinary surgical epilepsy center, adjunctive presurgical studies [e.g., PET, SPECT, MEG, electrical source imaging (ESI), EEG-functional magnetic resonance imaging (fMRI)], even when available, are rarely ordered, and this may contribute to excessive rates of VNS in lieu of definitive intracranial surgery.

Resource use and costs associated with epilepsy in the Queensland hospital system: protocol for a population-based data linkage study

INTRODUCTION

Epilepsy places a large burden on health systems, with hospitalisations for seizures alone occurring more frequently than those related to diabetes. However, the cost of epilepsy to the Australian health system is not well understood. The primary aim of this study is to quantify the health service use and cost of epilepsy in Queensland, Australia. Secondary aims are to identify differences in health service use and cost across population and disease subgroups, and to explore the associations between health service use and common comorbidities.

METHODS AND ANALYSIS

This project will use data linkage to identify the health service utilisation and costs associated with epilepsy. A base cohort of patients will be identified from the Queensland Hospital Admitted Patient Data Collection. We will select all patients admitted between 2014 and 2018 with a diagnosis classification related to epilepsy. Two comparison cohorts will also be identified. Retrospective hospital admissions data will be linked with emergency department presentations, clinical costing data, specialist outpatient and allied health occasions of service data and mortality data. The level of health service use in Queensland, and costs associated with this, will be quantified using descriptive statistics. Difference in health service costs between groups will be explored using logistic regression. Linear regression will be used to model the associations of interest. The analysis will adjust for confounders including age, sex, comorbidities, indigenous status, and remoteness.

ETHICS AND DISSEMINATION

Ethical approval has been obtained through the QUT University Human Research Ethics Committee (1900000333). Permission to waive consent has been granted under the Public Health Act 2005, with approval provided by all relevant data custodians. Findings of the proposed research will be communicated through presentations at national and international conferences, presentations to key stakeholders and decision-makers, and publications in international peer-reviewed journals.

Disparities in the nationwide distribution of epilepsy centers

BACKGROUND

Prior studies in the field of epilepsy surgical disparities have examined barriers in undergoing epilepsy surgical resections in disadvantaged populations involving trust in health providers, education level, social support, and fear of treatment. Few studies have analyzed the geographical locations of specialized epilepsy centers and their role in nationwide epilepsy surgical access and disparities.

OBJECTIVE

To better visualize the locations of epilepsy level IV centers in the United States with respect to epilepsy prevalence and socioeconomic disadvantage.

METHODS

We created heat maps of the United States to visualize geographical locations of level IV epilepsy centers with respect to the 2015 state-wide epilepsy prevalence and 2017 county-wide Area Deprivation Index (ADI) scores, a composite measure of socioeconomic disadvantage. Univariate logistic regression was used to test for associations between the presence or absence of epilepsy centers and socioeconomic disadvantage.

RESULTS

We found eight states within the United States without any level IV epilepsy centers. In states with level IV centers, centers were clustered in populated and metropolitan regions. Disadvantaged counties (with increased ADI scores) were less likely to have level IV centers compared to counties that were less disadvantaged (lower ADI scores) (p < 0.00001).

CONCLUSION

Further work is required to remedy the decreased access to specialized epilepsy care due to geographical disparities, and to better understand its contribution to overall disparities affecting epilepsy surgery referrals.

Machine learning models for decision support in epilepsy management: A critical review

PURPOSE

There remain major challenges for the clinician in managing patients with epilepsy effectively. Choosing anti-seizure medications (ASMs) is subject to trial and error. About one-third of patients have drug-resistant epilepsy (DRE). Surgery may be considered for selected patients, but time from diagnosis to surgery averages 20 years. We reviewed the potential use of machine learning (ML) predictive models as clinical decision support tools to help address some of these issues.

METHODS

We conducted a comprehensive search of Medline and Embase of studies that investigated the application of ML in epilepsy management in terms of predicting ASM responsiveness, predicting DRE, identifying surgical candidates, and predicting epilepsy surgery outcomes. Original articles addressing these 4 areas published in English between 2000 and 2020 were included.

RESULTS

We identified 24 relevant articles: 6 on ASM responsiveness, 3 on DRE prediction, 2 on identifying surgical candidates, and 13 on predicting surgical outcomes. A variety of potential predictors were used including clinical, neuropsychological, imaging, electroencephalography, and health system claims data. A number of different ML algorithms and approaches were used for prediction, but only one study utilized deep learning methods. Some models show promising performance with areas under the curve above 0.9. However, most were single setting studies (18 of 24) with small sample sizes (median number of patients 55), with the exception of 3 studies that utilized large databases and 3 studies that performed external validation. There was a lack of standardization in reporting model performance. None of the models reviewed have been prospectively evaluated for their clinical benefits.

CONCLUSION

The utility of ML models for clinical decision support in epilepsy management remains to be determined. Future research should be directed toward conducting larger studies with external validation, standardization of reporting, and prospective evaluation of the ML model on patient outcomes.

Adopting MR-guided stereotactic laser ablations for epileptic lesions: initial clinical experience and lessons learned

OBJECTIVE

MR-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive technique for ablating brain lesions under real-time MRI feedback and control of the ablation process. The Medtronic Visualase system was recently approved for use in Europe and Israel. We report our initial technical experience using the system in the first 16 cases in which the system was used to ablate focal epileptogenic lesions.

METHODS

We included all consecutive patients with intractable epilepsy who underwent MRgLITT procedures between 2018 and 2020. We reviewed medical charts and imaging studies of patients. Post-ablation MRIs were used to calculate ablation volumes.

RESULTS

Seventeen MRgLITT procedures were performed in 16 patients. One cooling catheter/laser fiber assemblies were placed per patient. Indications for surgery were intractable epilepsy due to TLE (n = 7), suspected low-grade glioma (n = 4), radiological cortical dysplasia (n = 1), hypothalamic hamartoma (n = 1), and MR-negative foci (n = 3). Ablations were made using 30 to 70% of the maximal energy of the Visualase system. We used serial ablations as needed along the tract of the catheter by pulling back the optic fiber; the length of the lesion ranged between 7.4 and 38.1 mm. Ablation volume ranged between 0.27 and 6.78 mm³. Immediate post-ablation MRI demonstrated good ablation of the epileptic lesion in 16/17 cases. In one case with mesial temporal sclerosis, no ablation was performed due to suboptimal position of the catheter. That patient was successfully reoperated at a later date. Mean follow-up was 14.9 months (± 11.6 months). Eleven patients had follow-up longer than 12 months. Good seizure control (Engel I, A) was achieved in 7/11 patients (63%) and 1/11 (9%) had significant improvement in seizure frequency (Angle IIIa). Three patients (27%) did not experience improvement in their seizure frequency (Engel IV, B), and one of these patients died during the follow-up period from sudden unexpected death of epilepsy (SUDEP). No immediate or delayed neurological complications were documented in any of the cases during the follow-up period.

CONCLUSIONS

MRgLITT is a promising technique and can be used safely as an alternative to open resection in both lesional and non-lesional intractable epilepsy cases. In our local series, the success rate of epilepsy surgery was comparable to recent publications.

A journey into the unknown: An ethnographic examination of drug-resistant epilepsy treatment and management in the United States

Patients often recognize unmet needs that can improve patient-provider experiences in disease treatment management. These needs are rarely captured and may be hard to quantify in difficult-to-treat disease states such as drug-resistant epilepsy (DRE). To further understand challenges living with and managing DRE, a team of medical anthropologists conducted ethnographic field assessments with patients to qualitatively understand their experience with DRE across the United States. In addition, healthcare provider assessments were conducted in community clinics and Comprehensive Epilepsy Centers to further uncover patient-provider treatment gaps. We identified four distinct stages of the treatment and management journey defined by patients' perceived control over their epilepsy: Gripped in the Panic Zone, Diligently Tracking to Plan, Riding a Rollercoaster in the Dark, and Reframing Priorities to Redefine Treatment Success. We found that patients sought resources to streamline communication with their care team, enhanced education on treatment options beyond medications, and long-term resources to protect against a decline in control over managing their epilepsy once drug-resistant. Likewise, treatment management optimization strategies are provided to improve current DRE standard of care with respect to identified patient-provider gaps. These include the use of digital disease management tools, standardizing neuropsychiatrists into patients' initial care team, and introducing surgical and non-pharmacological treatment options upon epilepsy and DRE diagnoses, respectively. This ethnographic study uncovers numerous patient-provider gaps, thereby presenting a conceptual framework to advance DRE treatment. Further Incentivization from professional societies and healthcare systems to support standardization of the treatment optimization strategies provided herein into clinical practice is needed.

Extrapial Hippocampal Resection in Anterior Temporal Lobectomy: Technical Description and Clinical Outcomes in a 62-Patient Case Series

BACKGROUND

Anterior temporal lobectomy (ATL) is the most effective treatment for drug-resistant mesial temporal lobe epilepsy. Extrapial en bloc hippocampal resection facilitates complete removal of the hippocampus. With increasing use of minimally invasive treatments, considering open resection techniques that optimize the integrity of tissue specimens is important both for obtaining the correct histopathological diagnosis and for further study.

OBJECTIVE

To describe the operative strategy and clinical outcomes associated with an extrapial approach to hippocampal resection during ATL.

METHODS

A database of epilepsy surgeries performed by a single surgeon between October 2011 and February 2019 was reviewed to identify all patients who underwent ATL using an extrapial approach to hippocampal resection. To reduce confounding variables for outcome analysis, subjects with prior resections, tumors, and cavernous malformations were excluded. Seizure outcomes were classified using the Engel scale.

RESULTS

The surgical technique is described and illustrated with intraoperative images. A total of 62 patients met inclusion criteria (31 females) for outcome analysis. Patients with most recent follow-up <3 yr (n = 33) and >3 yr (n = 29) exhibited 79% and 52% class I outcomes, respectively. An infarct was observed on postoperative magnetic resonance imaging in 3 patients (1 asymptomatic and 2 temporarily symptomatic). An en bloc specimen in which the subiculum and all hippocampal subfields were preserved was obtained in each case. Examples of innovative research opportunities resulting from this approach are presented.

CONCLUSION

Extrapial resection of the hippocampus can be performed safely with seizure freedom and complication rates at least as good as those reported with the use of subpial techniques.

Budget Impact Analysis of Treatment Flow Optimization in Epilepsy Patients: Estimating Potential Impacts with Increased Referral Rate to Specialized Care

Objectives: We developed a Markov model to simulate a treatment flow of epilepsy patients who refer to specialized care from non-specialized care, and to surgery from specialized care for estimation of patient distributions and expenditures caused by increasing the referral rate for specialized care. Methods: This budget impact analysis of treatment flow optimization in epilepsy patients was performed as a long-term simulation using the Markov model by comparing the current treatment flow and the optimized treatment flow. In the model, we simulated the prognosis of new onset 5-year-old epilepsy patients (assuming to represent epilepsy occurring between 0 and 10 years of age) treated over a lifetime period. Direct costs of pharmacotherapies, management fees and surgeries are included in the analysis to evaluate the annual budget impact in Japan. Results: In the current treatment flow, the number of refractory patients treated with four drugs by non-specialized care were estimated as 8766 and yielded JPY5.8 billion annually. However, in the optimized treatment flow, the number of patients treated with four drugs by non-specialized care significantly decreased and who continued the monotherapy increased. The costs for the four-drug therapy by non-specialized care were eliminated. Hence cost-saving of JPY9.5 billion (-5% of the current treatment flow) in total national expenditures would be expected. Conclusion: This study highlights that any policy decision-making for referral optimization to specialized care in appropriate epilepsy patients would be feasible with a cost-savings or very few budget impacts. However, important information in the decision-making such as transition probability to the next therapy or excuse for sensitive limitations is not available currently. Therefore, further research with reliable data such as big data analysis or a national survey with real-world treatment patterns is needed.

Stereoelectroencephalography versus Subdural Electrode Implantation to Determine Whether Patients with Drug-resistant Epilepsy Are Candidates for Epilepsy Surgery

Epilepsy is a chronic condition that affects about 50 million individuals worldwide. While its challenges are profound, there are increasing instances where antiepileptic drugs (AEDs) fail to provide relief to epileptic manifestations. For these pharmacoresistant cases, epilepsy surgery often is an effective route for treatment. However, the complexity and challenges associated with presurgical evaluations have prevented more widespread utilization of epilepsy surgery in pharmacoresistant cases. While preliminary work-ups and non-invasive diagnostic imaging have allowed for limited identification of the epileptogenic zone (EZ), there is yet to be an established pre-determined algorithm for surgical evaluation of patients with epilepsy. However, two modalities are currently being used for localization of the EZ and in determining candidates for surgery: stereoelectroencephalography (SEEG) and subdural electrodes (SDEs). SDE has been used in the United States for decades; however, SEEG now provides a less invasive option for mapping brain regions. We seek to address which intracranial monitoring technique is superior. Through a review of the outcomes of various clinical studies, SEEG was found to have greater safety and efficiency benefits than SDE, such as lower morbidity rates, lower prevalence of neurological deficits, and shorter recovery times. Moreover, SEEG was also found to have further functional benefits by allowing for deeper targeting of cerebral tissue along with bilateral hemispheric monitoring. This has led to increased rates of seizure freedom and control among SEEG patients. Nevertheless, further studies on the limitations and advancements of SEEG and SDE are still required to provide a more comprehensive understanding regarding their application.

Underutilization of epilepsy surgery: Part I: A scoping review of barriers

One-third of persons with epilepsy have seizures despite appropriate medical therapy. Drug resistant epilepsy (DRE) is associated with neurocognitive and psychological decline, poor quality of life, increased risk of premature death, and greater economic burden. Epilepsy surgery is an effective and safe treatment for a subset of people with DRE but remains one of the most underutilized evidence-based treatments in modern medicine. The reasons for this quality gap are insufficiently understood. In this comprehensive review, we compile known significant barriers to epilepsy surgery, originating from both patient/family-related factors and physician/health system components. Important patient-related factors include individual and epilepsy characteristics which bias towards continued preferential use of poorly effective medications, as well as patient perspectives and misconceptions of surgical risks and benefits. Health system and physician-related barriers include demonstrable knowledge gaps among physicians, inadequate access to comprehensive epilepsy centers, complex presurgical evaluations, insufficient research, and socioeconomic bias when choosing appropriate surgical candidates.

Transcranial direct current stimulation (tDCS) in the management of epilepsy: A systematic review

PURPOSE

Current therapies for the management of epilepsy are still suboptimal for several patients due to inefficacy, major adverse events, and unavailability. Transcranial direct current stimulation (tDCS), an emergent non-invasive neuromodulation technique, has been tested in epilepsy samples over the past two decades to reduce either seizure frequency or electroencephalogram (EEG) epileptiform discharges.

METHODS

A systematic review was performed in accordance with PRISMA guidelines (PROSPERO record CRD42020160292). A thorough electronic search was completed in MEDLINE, EMBASE, CENTRAL and Scopus databases for trials that applied tDCS interventions to children and adults with epilepsy of any cause, from inception to April 30, 2020.

RESULTS

Twenty-seven studies fulfilled eligibility criteria, including nine sham-controlled and 18 uncontrolled trials or case reports/series. Samples consisted mainly of drug-resistant focal epilepsy patients that received cathodal tDCS stimulation targeted at the site with maximal EEG abnormalities. At follow-up, 84 % (21/25) of the included studies reported a reduction in seizure frequency and in 43 % (6/14) a decline in EEG epileptiform discharge rate was observed. No serious adverse events were reported.

CONCLUSIONS

Cathodal tDCS is both a safe and probably effective technique for seizure control in patients with drug-resistant focal epilepsy. However, published trials are heterogeneous regarding samples and methodology. More and larger sham-controlled randomized trials are needed, preferably with mechanistic informed stimulation protocols, to further advance tDCS therapy in the management of epilepsy.

Patient navigation in epilepsy care

The concept of patient navigation was first introduced in 1989 by the American Cancer Society and was first implemented in 1990 by Dr. Harold Freeman in Harlem, NY. The role of a patient navigator (PN) is to coordinate care between the care team, the patient, and their family while also providing social support. In the last 30 years, patient navigation in oncological care has expanded internationally and has been shown to significantly improve patient care experience, especially in the United States cancer care system. Like oncology care, patients who require epilepsy care face socioeconomic and healthcare system barriers and are at significant risk of morbidity and mortality if their care needs are not met. Although shortcomings in epilepsy care are longstanding, the COVID-19 pandemic has exacerbated these issues as both patients and providers have reported significant delays in care secondary to the pandemic. Prior to the pandemic, preliminary studies had shown the potential efficacy of patient navigation in improving epilepsy care. Considering the evidence that such programs are helpful for severely disadvantaged cancer patients and in enhancing epilepsy care, we believe that professional societies should support and encourage PN programs for coordinated and comprehensive care for patients with epilepsy.