Clinical outcomes among initial survivors of cryptogenic new-onset refractory status epilepsy (NORSE).

OBJECTIVE: New-onset refractory status epilepticus (NORSE) is a rare but severe clinical syndrome. Despite rigorous evaluation, the underlying cause is unknown in 30%-50% of patients and treatment strategies are largely empirical. The aim of this study was to describe clinical outcomes in a cohort of well-phenotyped, thoroughly investigated patients who survived the initial phase of cryptogenic NORSE managed in specialist centers. METHODS: Well-characterized cases of cryptogenic NORSE were identified through the EPIGEN and Critical Care EEG Monitoring Research Consortia (CCEMRC) during the period 2005-2019. Treating epileptologists reported on post-NORSE survival rates and sequelae in patients after discharge from hospital. Among survivors >6 months post-discharge, we report the rates and severity of active epilepsy, global disability, vocational, and global cognitive and mental health outcomes. We attempt to identify determinants of outcome. RESULTS: Among 48 patients who survived the acute phase of NORSE to the point of discharge from hospital, 9 had died at last follow-up, of whom 7 died within 6 months of discharge from the tertiary care center. The remaining 39 patients had high rates of active epilepsy as well as vocational, cognitive, and psychiatric comorbidities. The epilepsy was usually multifocal and typically drug resistant. Only a minority of patients had a good functional outcome. Therapeutic interventions were heterogenous during the acute phase of the illness. There was no clear relationship between the nature of treatment and clinical outcomes. SIGNIFICANCE: Among survivors of cryptogenic NORSE, longer-term outcomes in most patients were life altering and often catastrophic. Treatment remains empirical and variable. There is a pressing need to understand the etiology of cryptogenic NORSE and to develop tailored treatment strategies.

Rare Genetic Variation and Outcome of Surgery for Mesial Temporal Lobe Epilepsy.

OBJECTIVE: Genetic factors have long been debated as a cause of failure of surgery for mesial temporal lobe epilepsy (MTLE). We investigated whether rare genetic variation influences seizure outcomes of MTLE surgery. METHODS: We performed an international, multicenter, whole exome sequencing study of patients who underwent surgery for drug-resistant, unilateral MTLE with normal magnetic resonance imaging (MRI) or MRI evidence of hippocampal sclerosis and ≥2-year postsurgical follow-up. Patients with either sustained seizure freedom (favorable outcome) or ongoing uncontrolled seizures since surgery (unfavorable outcome) were included. Exomes of controls without epilepsy were also included. Gene set burden analyses were carried out to identify genes with significant enrichment of rare deleterious variants in patients compared to controls. RESULTS: Nine centers from 3 continents contributed 206 patients operated for drug-resistant unilateral MTLE, of whom 196 (149 with favorable outcome and 47 with unfavorable outcome) were included after stringent quality control. Compared to 8,718 controls, MTLE cases carried a higher burden of ultrarare missense variants in constrained genes that are intolerant to loss-of-function (LoF) variants (odds ratio [OR] = 2.6, 95% confidence interval [CI] = 1.9-3.5, p = 1.3E-09) and in genes encoding voltage-gated cation channels (OR = 2.4, 95% CI = 1.4-3.8, p = 2.7E-04). Proportions of subjects with such variants were comparable between patients with favorable outcome and those with unfavorable outcome, with no significant between-group differences. INTERPRETATION: Rare variation contributes to the genetic architecture of MTLE, but does not appear to have a major role in failure of MTLE surgery. These findings can be incorporated into presurgical decision-making and counseling. ANN NEUROL 2022.

Knowledge and beliefs about epilepsy genetics among Hispanic and non-Hispanic patients.

OBJECTIVE: Hispanics continue to face challenges when trying to access health care, including epilepsy care and genetic-related health care services. This study examined epilepsy genetic knowledge and beliefs in this historically underserved population. METHODS: Questionnaires were completed by 641 adults with epilepsy without identified cause, of whom 122 self-identified as Hispanic or Latino and 519 as non-Hispanic. Participants were asked about their views on the contribution of genetics to the cause of their epilepsy ("genetic attribution"), optimism for advancements in epilepsy genetic research ("genetic optimism"), basic genetic knowledge, and epilepsy-specific genetic knowledge. Generalized linear models were used to compare the two groups in the means of quantitative measures and percents answered correctly for individual genetic knowledge items. Analyses were adjusted for age, sex, education, religion, family history of epilepsy, and time since last seizure. RESULTS: Hispanics did not differ from non-Hispanics in genetic attribution, genetic optimism, or number of six basic genetic knowledge items answered correctly. The number of nine epilepsy-specific genetic knowledge items answered correctly was significantly lower for Hispanics than non-Hispanics (adjusted mean = 6.0 vs. 6.7, p < .001). After adjustment for education and other potential mediators, the proportion answered correctly was significantly lower for Hispanics than non-Hispanics for only two items related to family history and penetrance of epilepsy-related genes. Only 54% of Hispanics and 61% of non-Hispanics answered correctly that "If a person has epilepsy, his or her relatives have an increased chance of getting epilepsy." SIGNIFICANCE: Despite large differences in sociodemographic variables including education, most attitudes and beliefs about genetics were similar in Hispanics and non-Hispanics. Epilepsy-specific genetic knowledge was lower among Hispanics than non-Hispanics, and this difference was mostly mediated by differences in demographic variables. Genetic counseling should address key concepts related to epilepsy genetics to ensure they are well understood by both Hispanic and non-Hispanic patients.

Clinical presentation and evaluation of epilepsy with eyelid myoclonia: Results of an international expert consensus panel.

OBJECTIVE: The objective of this study was to determine areas of consensus among an international panel of experts for the clinical presentation and diagnosis of epilepsy with eyelid myoclonia (EEM; formerly known as Jeavons syndrome) to improve a timely diagnosis. METHODS: An international steering committee was convened of physicians and patients/caregivers with expertise in EEM. This committee summarized the current literature and identified an international panel of experts (comprising 25 physicians and five patients/caregivers). This international expert panel participated in a modified Delphi process, including three rounds of surveys to determine areas of consensus for the diagnosis of EEM. RESULTS: There was a strong consensus that EEM is a female predominant generalized epilepsy syndrome with onset between 3 and 12 years of age and that eyelid myoclonia must be present to make the diagnosis. There was a strong consensus that eyelid myoclonia may go unrecognized for years prior to an epilepsy diagnosis. There was consensus that generalized tonic-clonic and absence seizures are typically or occasionally seen in patients. There was a consensus that atonic or focal seizures should lead to the consideration of reclassification or alternate diagnoses. There was a strong consensus that electroencephalography is required, whereas magnetic resonance imaging is not required for diagnosis. There was a strong consensus to perform genetic testing (either epilepsy gene panel or whole exome sequencing) when one or a combination of factors was present: family history of epilepsy, intellectual disability, or drug-resistant epilepsy. SIGNIFICANCE: This international expert panel identified multiple areas of consensus regarding the presentation and evaluation of EEM. These areas of consensus may be used to inform clinical practice to shorten the time to the appropriate diagnosis.

Management of epilepsy with eyelid myoclonia: Results of an international expert consensus panel.

OBJECTIVE: There are limited data about the treatment and management of epilepsy with eyelid myoclonia (EEM). The objective of this study was to determine areas of consensus among an international panel of experts for the management of EEM (formerly known as Jeavons syndrome). METHODS: An international steering committee was convened of physicians and patients/caregivers with expertise in EEM. This committee summarized the current literature and identified an international panel of experts (comprising 25 physicians and five patients/caregivers). This panel participated in a modified Delphi process, including three rounds of surveys to determine areas of consensus for the treatment, other areas of management, and prognosis for EEM. RESULTS: There was a strong consensus for valproic acid as the first-line treatment, with levetiracetam or lamotrigine as preferable alternatives for women of childbearing age. There was a moderate consensus that ethosuximide and clobazam are also efficacious. There was a strong consensus to avoid sodium channel-blocking medications, except for lamotrigine, as they may worsen seizure control. There was consensus that seizures typically persist into adulthood, with remission occurring in <50% of patients. There was less agreement about other areas of management, including dietary therapy, lens therapy, candidacy for driving, and outcome. SIGNIFICANCE: This international expert panel identified multiple areas of consensus regarding the optimal management of EEM. These areas of consensus may inform clinical practice to improve the management of EEM. In addition, multiple areas with less agreement were identified, which highlight topics for further research.

Association of antiseizure medication adherence with illness perceptions in adults with epilepsy.

OBJECTIVE: We assessed the relationship of epilepsy illness perceptions to antiseizure medication (ASM) adherence. METHODS: Surveys were completed by 644 adult patients with epilepsy of unknown cause. We used the Morisky Medication Adherence Scale-8 (MMAS-8) to define "high" adherence (score = 8) and "low-medium" adherence (score < 8). We evaluated epilepsy illness perceptions using seven items from the Brief Illness Perception Questionnaire (BIPQ), each scored from 0-10, measuring participants' views of the overall effect of epilepsy on their lives, how long it would last, how much control they had over their epilepsy, the effectiveness of their treatment, level of concern about epilepsy, level of understanding of epilepsy, and emotional impact of epilepsy. We investigated the association of each BIPQ item with medication adherence using logistic regression models that controlled for potential confounders (age, race/ethnicity, income, and time since the last seizure). RESULTS: One hundred forty-nine patients (23%) gave responses indicating high adherence. In the adjusted models, for each 1-unit increase in participants' BIPQ item scores, the odds of high adherence increased by 17% for understanding of their epilepsy (OR = 1.17, 95% CI 1.07-1.27, p < 0.001), decreased by 11% for overall life impact of epilepsy (OR = 0.89, 95% CI 0.82-0.97, p = 0.01) and decreased by 6% for emotional impact of epilepsy (OR = 0.94, 95% CI 0.86-0.99, p = 0.03). No other illness perception was associated with high adherence. Depression, anxiety, and stigma mediated the inverse relationships of high adherence to the overall life impact of epilepsy and the emotional impact of epilepsy. These measures did not mediate the relationship of high adherence to the perceived understanding of epilepsy. CONCLUSION: These results indicate that a greater perceived understanding of epilepsy is independently associated with high ASM adherence. Programs aimed at improving patients' understanding of their epilepsy may help improve medication adherence.

Genomic analysis of "microphenotypes" in epilepsy.

Large international consortia examining the genomic architecture of the epilepsies focus on large diagnostic subgroupings such as "all focal epilepsy" and "all genetic generalized epilepsy". In addition, phenotypic data are generally entered into these large discovery databases in a unidirectional manner at one point in time only. However, there are many smaller phenotypic subgroupings in epilepsy, many of which may have unique genomic risk factors. Such a subgrouping or "microphenotype" may be defined as an uncommon or rare phenotype that is well recognized by epileptologists and the epilepsy community, and which may or may not be formally recognized within the International League Against Epilepsy classification system. Here we examine the genetic structure of a number of such microphenotypes and report in particular on two interesting clinical phenotypes, Jeavons syndrome and pediatric status epilepticus. Although no single gene reached exome-wide statistical significance to be associated with any of the diagnostic categories, we observe enrichment of rare damaging variants in established epilepsy genes among Landau-Kleffner patients (GRIN2A) and pediatric status epilepticus patients (MECP2, SCN1A, SCN2A, SCN8A).

Antiseizure medication treatment pathways for US Medicare beneficiaries with newly treated epilepsy.

OBJECTIVE: This study was undertaken to characterize antiseizure medication (ASM) treatment pathways in Medicare beneficiaries with newly treated epilepsy. METHODS: This was a retrospective cohort study using Medicare claims. Medicare is the United States' federal health insurance program for people aged 65 years and older plus younger people with disabilities or end-stage renal disease. We included beneficiaries with newly treated epilepsy (International Classification of Diseases codes for epilepsy/convulsions 2014-2017, no ASM in the previous 2 years). We displayed the sequence of ASM fills using sunburst plots overall, then stratified by mood disorder, age, and neurologist prescriber. We tabulated drug costs for each pathway. RESULTS: We included 21 458 beneficiaries. Levetiracetam comprised the greatest number of pill days (56%), followed by gabapentin (11%) and valproate (8%). There were 22 288 unique treatment pathways. The most common pathways were levetiracetam monotherapy (43%), gabapentin monotherapy (10%), and valproate monotherapy (5%). Gabapentin was the most common second- and third-line ASM. Whereas only 2% of pathways involved first-line lacosamide, those pathways accounted for 19% of cost. Gabapentin and valproate use was increased and levetiracetam use was decreased in beneficiaries with mood disorders compared to beneficiaries without mood disorders. Levetiracetam use was increased and gabapentin, valproate, lamotrigine, and topiramate use was decreased in beneficiaries aged >65 years compared with those aged 65 years or less. Lamotrigine, levetiracetam, and lacosamide use was increased and gabapentin use was decreased in beneficiaries whose initial prescriber was a neurologist compared to those whose prescriber was not a neurologist. SIGNIFICANCE: Levetiracetam monotherapy was the most common pathway, although substantial heterogeneity existed. Lacosamide accounted for a small percentage of ASMs but a disproportionately large share of cost. Neurologists were more likely to prescribe lamotrigine compared with nonneurologists, and lamotrigine was prescribed far less frequently than may be endorsed by guidelines. Future work may explore patient- and physician-driven factors underlying ASM choices.

Reproduction and genetic causal attribution of epilepsy.

OBJECTIVE: This study addresses the contribution of genetics-related concerns to reduced childbearing among people with epilepsy. METHODS: Surveys were completed by 606 adult patients with epilepsy of unknown cause at our medical center. Poisson regression analysis was used to assess the relations of number of offspring to: (1) genetic attribution (GA: participants' belief that genetics was a cause of their epilepsy), assessed via a novel scale developed from four survey items (Cronbach's alpha = .89), (2) participants' estimates of epilepsy risk in the child of a parent with epilepsy (1%, 5%-10%, 25%, and 50%-100%), and (3) participants' reports of the influence on their reproductive decisions of "the chance of having a child with epilepsy" (none/weak/moderate, strong/very strong). Analyses were adjusted for age, education, race/ethnicity, religion, type of epilepsy (generalized, focal, and both/unclassifiable), and age at epilepsy onset (<10, 10-19, and ≥20 years). RESULTS: Among participants 18-45 years of age, the number of offspring decreased significantly with increasing GA (highest vs lowest GA quartile rate ratio [RR] = .5, p < .001), and increasing estimated epilepsy risk in offspring (with 5%-10% as referent because it is closest to the true value, RR for 25%: .7, p = .05; RR for 50%-100%: .6, p = .03). Number of offspring was not related to the reported influence of "the chance of having a child with epilepsy" on reproductive decisions. Among participants >45 years of age, the number of offspring did not differ significantly according to GA quartile or estimated offspring epilepsy risk. However, those reporting a strong/very strong influence on their reproductive decisions of "the chance of having a child with epilepsy" had only 60% as many offspring as others. SIGNIFICANCE: These findings suggest that overestimating the risk of epilepsy in offspring can have important consequences for people with epilepsy. Patient and provider education about recurrence risks and genetic testing options to clarify risks are critical, given their potential influence on reproductive decisions.

Clinical and EEG factors associated with antiseizure medication resistance in idiopathic generalized epilepsy.

OBJECTIVE: We sought to determine which combination of clinical and electroencephalography (EEG) characteristics differentiate between an antiseizure medication (ASM)-resistant vs ASM-responsive outcome for patients with idiopathic generalized epilepsy (IGE). METHODS: This was a case-control study of ASM-resistant cases and ASM-responsive controls with IGE treated at five epilepsy centers in the United States and Australia between 2002 and 2018. We recorded clinical characteristics and findings from the first available EEG study for each patient. We then compared characteristics of cases vs controls using multivariable logistic regression to develop a predictive model of ASM-resistant IGE. RESULTS: We identified 118 ASM-resistant cases and 114 ASM-responsive controls with IGE. First, we confirmed our recent finding that catamenial epilepsy is associated with ASM-resistant IGE (odds ratio [OR] 3.53, 95% confidence interval [CI] 1.32-10.41, for all study subjects) after covariate adjustment. Other independent factors seen with ASM resistance include certain seizure-type combinations (absence, myoclonic, and generalized tonic-clonic seizures [OR 7.06, 95% CI 2.55-20.96]; absence and generalized tonic-clonic seizures [OR 4.45, 95% CI 1.84-11.34]), as well as EEG markers of increased generalized spike-wave discharges (GSWs) in sleep (OR 3.43, 95% CI 1.12-11.36 for frequent and OR 7.21, 95% CI 1.50-54.07 for abundant discharges in sleep) and the presence of generalized polyspike trains (GPTs; OR 5.49, 95% CI 1.27-38.69). The discriminative ability of our final multivariable model, as measured by area under the receiver-operating characteristic curve, was 0.80. SIGNIFICANCE: Multiple clinical and EEG characteristics independently predict ASM resistance in IGE. To improve understanding of a patient's prognosis, clinicians could consider asking about specific seizure-type combinations and track whether they experience catamenial epilepsy. Obtaining prolonged EEG studies to record the burden of GSWs in sleep and assessing for the presence of GPTs may provide additional predictive value.

Identification of patients with drug-resistant epilepsy in electronic medical record data using the Observational Medical Outcomes Partnership Common Data Model.

OBJECTIVE: More than one third of appropriately treated patients with epilepsy have continued seizures despite two or more medication trials, meeting criteria for drug-resistant epilepsy (DRE). Accurate and reliable identification of patients with DRE in observational data would enable large-scale, real-world comparative effectiveness research and improve access to specialized epilepsy care. In the present study, we aim to develop and compare the performance of computable phenotypes for DRE using the Observational Medical Outcomes Partnership (OMOP) Common Data Model. METHODS: We randomly sampled 600 patients from our academic medical center's electronic health record (EHR)-derived OMOP database meeting previously validated criteria for epilepsy (January 2015-August 2021). Two reviewers manually classified patients as having DRE, drug-responsive epilepsy, undefined drug responsiveness, or no epilepsy as of the last EHR encounter in the study period based on consensus definitions. Demographic characteristics and codes for diagnoses, antiseizure medications (ASMs), and procedures were tested for association with DRE. Algorithms combining permutations of these factors were applied to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for DRE. The F1 score was used to compare overall performance. RESULTS: Among 412 patients with source record-confirmed epilepsy, 62 (15.0%) had DRE, 163 (39.6%) had drug-responsive epilepsy, 124 (30.0%) had undefined drug responsiveness, and 63 (15.3%) had insufficient records. The best performing phenotype for DRE in terms of the F1 score was the presence of ≥1 intractable epilepsy code and ≥2 unique non-gabapentinoid ASM exposures each with ≥90-day drug era (sensitivity = .661, specificity = .937, PPV = .594, NPV = .952, F1 score = .626). Several phenotypes achieved higher sensitivity at the expense of specificity and vice versa. SIGNIFICANCE: OMOP algorithms can identify DRE in EHR-derived data with varying tradeoffs between sensitivity and specificity. These computable phenotypes can be applied across the largest international network of standardized clinical databases for further validation, reproducible observational research, and improving access to appropriate care.

Patient characteristics and antiseizure medication pathways in newly diagnosed epilepsy: Feasibility and pilot results using the common data model in a single-center electronic medical record database.

INTRODUCTION: Efforts to characterize variability in epilepsy treatment pathways are limited by the large number of possible antiseizure medication (ASM) regimens and sequences, heterogeneity of patients, and challenges of measuring confounding variables and outcomes across institutions. The Observational Health Data Science and Informatics (OHDSI) collaborative is an international data network representing over 1 billion patient records using common data standards. However, few studies have applied OHDSI's Common Data Model (CDM) to the population with epilepsy and none have validated relevant concepts. The goals of this study were to demonstrate the feasibility of characterizing adult patients with epilepsy and ASM treatment pathways using the CDM in an electronic health record (EHR)-derived database. METHODS: We validated a phenotype algorithm for epilepsy in adults using the CDM in an EHR-derived database (2001-2020) against source records and a prospectively maintained database of patients with confirmed epilepsy. We obtained the frequency of all antecedent conditions and procedures for patients meeting the epilepsy phenotype criteria and characterized ASM exposure sequences over time and by age and sex. RESULTS: The phenotype algorithm identified epilepsy with 73.0-85.0% positive predictive value and 86.3% sensitivity. Many patients had neurologic conditions and diagnoses antecedent to meeting epilepsy criteria. Levetiracetam incrementally replaced phenytoin as the most common first-line agent, but significant heterogeneity remained, particularly in second-line and subsequent agents. Drug sequences included up to 8 unique ingredients and a total of 1,235 unique pathways were observed. CONCLUSIONS: Despite the availability of additional ASMs in the last 2 decades and accumulated guidelines and evidence, ASM use varies significantly in practice, particularly for second-line and subsequent agents. Multi-center OHDSI studies have the potential to better characterize the full extent of variability and support observational comparative effectiveness research, but additional work is needed to validate covariates and outcomes.

Differences in elective epilepsy monitoring unit admission rates by race/ethnicity and primary payer in New Jersey.

Elective admission to the epilepsy monitoring unit (EMU) is an essential service provided by epilepsy centers, particularly for those with drug-resistant epilepsy. Given previously characterized racial and socioeconomic healthcare disparities in the management of epilepsy, we sought to understand access and utilization of this service in New Jersey (NJ). We examined epilepsy hospitalizations in NJ between 2014 and 2016 using state inpatient and emergency department (ED) databases. We stratified admissions by race/ethnicity and primary payer and used these to estimate and compare (1) admission rates per capita in NJ, as well as (2) admission rates per number of ED visits for each group. Patients without insurance underwent elective EMU admission at the lowest rates across all racial/ethnic groups and payer types studied. Black patients with Medicaid and private insurance were admitted at disproportionately low rates relative to their number of ED visits. Hispanic/Latino and Asian/Pacific Islanders with private insurance, Hispanic/Latinos with Medicaid, and Asian/Pacific Islanders with Medicare were also admitted at low rates per capita within each respective payer category. Future studies should focus on addressing causal factors driving healthcare disparities in epilepsy, particularly for patients without adequate health insurance coverage and those who have been historically underserved by the healthcare system.

Cognitive decline in older adults with epilepsy: The Cardiovascular Health Study.

OBJECTIVE: Cognitive decline is a major concern for older adults with epilepsy. Whether and how much faster older adults with epilepsy experience cognitive decline beyond expected age-related cognitive change remain unclear. We sought to estimate and compare rates of cognitive decline in older adults with and without epilepsy. METHODS: The Cardiovascular Health Study is a population-based longitudinal cohort study of 5888 US adults aged 65+. Cognitive function was assessed annually with Modified Mini-Mental State Exam (3MS) and Digit Symbol Substitution Test (DSST). We used linear mixed models to estimate average rates of decline in 3MS and DSST scores by epilepsy status (prevalent, incident, or no epilepsy), adjusted for risk factors associated with cognitive decline. RESULTS: The rate of decline in 3MS was significantly faster in prevalent epilepsy (P < .001) and after incident epilepsy (P = .002) compared with no epilepsy. Prevalent epilepsy and apolipoprotein E gene (APOE) ε4 (ApoE4) had a synergistic interaction, whereby prevalent epilepsy and ApoE4 together were associated with 1.51 points faster annual decline in 3MS than would be expected if prevalent epilepsy and ApoE4 did not interact (P < .001). Older adults with prevalent epilepsy had a significantly lower initial DSST score and faster rate of decline compared to those with no epilepsy (P < .001). SIGNIFICANCE: Faster decline in global cognitive ability seen in this study validates concerns of patients. ApoE4 allele status was an effect modifier of the relationship between cognitive decline and prevalent epilepsy. Further research is warranted to explore biological mechanisms and possible interventions to mitigate cognitive decline.

All-cause mortality and SUDEP in a surgical epilepsy population.

Epilepsy surgery is considered to reduce the risk of epilepsy-related mortality, including sudden unexpected death in epilepsy (SUDEP), though data from existing surgical series are conflicting. We retrospectively examined all-cause mortality and SUDEP in a population of 590 epilepsy surgery patients and a comparison group of 122 patients with pharmacoresistant focal epilepsy who did not undergo surgery, treated at Columbia University Medical Center between 1977 and 2014. There were 34 deaths in the surgery group, including 14 cases of SUDEP. Standardized mortality ratio (SMR) for the surgery group was 1.6, and SUDEP rate was 1.9 per 1000 patient-years. There were 13 deaths in the comparison group, including 5 cases of SUDEP. Standardized mortality ratio for the comparison group was 3.6, and SUDEP rate was 4.6 per 1000 patient-years. Both were significantly greater than in the surgery group (p < 0.05). All but one of the surgical SUDEP cases, and all of the comparison group SUDEP cases, had a history of bilateral tonic-clonic seizures (BTCS). Of postoperative SUDEP cases, one was seizure-free, and two were free of BTCS at last clinical follow-up. Time to SUDEP in the surgery group was longer than in the comparison group (10.1 vs 5.9 years, p = 0.013), with 10 of the 14 cases occurring >10 years after surgery. All-cause mortality was reduced after epilepsy surgery relative to the comparison group. There was an early benefit of surgery on the occurrence of SUDEP, which was reduced after 10 years. A larger, multicenter study is needed to further investigate the time course of postsurgical SUDEP.

Cost-effectiveness of screening for HLA-B*1502 prior to initiation of carbamazepine in epilepsy patients of Asian ancestry in the United States.

OBJECTIVE: Carbamazepine, widely used in the treatment of partial and generalized tonic-clonic seizures, has been associated with life-threatening Stevens-Johnson syndrome/toxic epidermal necrolysis among some Asians. The HLA-B*1502 genotype that occurs with varying frequency among Asians is recommended for screening prior to starting carbamazepine. Our goal is to explore the cost-effectiveness of screening for the presence of this genetic allele. METHODS: We constructed a Markov model in a hypothetical cohort of adult Asian patients with epilepsy in the United States being considered for carbamazepine to investigate the cost-effectiveness of two alternative strategies: (1) no HLA-B*1502 gene allele screening and using carbamazepine and (2) HLA-B*1502 gene allele screening and starting levetiracetam in the case of a positive screen. RESULTS: For the lifetime horizon, HLA-B*1502 gene screening was the cost-effective choice compared to no gene screening, with an incremental cost-effectiveness ratio of $27 058 per quality-adjusted life-year (QALY), below the $50 000/QALY threshold in 99.69% of probabilistic sensitivity analyses. Although gene screening strategy was more expensive than a no screening strategy, it was more effective, yielding more QALYs, across all Asian ethnic groups. SIGNIFICANCE: Our analysis confirms the 2007 US Food and Drug Administration recommendation to screen for HLA-B*1502 allele before starting treatment with carbamazepine in patients of Asian ancestry in the United States.

Postictal clinical and electroencephalographic activity following intracranially recorded bilateral tonic-clonic seizures.

OBJECTIVE: The dynamics of the postictal period, which may demonstrate such dramatic clinical phenomena as focal neurological deficits, prolonged coma and immobility, and even sudden death, are poorly understood. We sought to classify and characterize postictal phases of bilateral tonic-clonic seizures based on electroencephalographic (EEG) criteria and associated clinical features. METHODS: We performed a detailed electroclinical evaluation of the postictal period in a series of 31 bilateral tonic-clonic seizures in 16 patients undergoing epilepsy surgery evaluations for focal pharmacoresistant epilepsy with intracranial electrodes and time-locked video. RESULTS: The postictal EEG demonstrated three clearly differentiated phases as follows: attenuation, a burst-attenuation pattern, and a return to continuous background, with abrupt, synchronized transitions between phases. Postictal attenuation was common, occurring in 84% of seizures in 94% of patients in this study. There was increased power in gamma frequencies (>25 Hz) during postictal attenuation periods relative to preictal baseline in 88% of seizures demonstrating the attenuation pattern (n = 25 seizures, P < 0.002). Such increases were seen in >90% of channels in 13 seizures (52%) and <10% of channels in three seizures (12%). Postictal immobility was seen in 87% of seizures, with either a flaccid (58%) or rigid/dystonic (29%) appearance. Clinical motor manifestations, including focal dystonic posturing, automatisms, head and eye deviation, and myoclonic jerking, continued or emerged within the first minute following seizure termination in 48% of seizures, regardless of EEG appearance. SIGNIFICANCE: Intracranial postictal attenuation, which may be diffuse or focal, is so common that it should be regarded as a ubiquitous feature of bilateral tonic-clonic seizures, rather than an unusual event. The prominence of high-frequency activity coupled with emerging clinical features, including rigid immobility and semiologies such as automatisms, during the postictal period supports the presence of ongoing seizure-related neuronal activity in unrecorded brain regions.

Laser ablation is effective for temporal lobe epilepsy with and without mesial temporal sclerosis if hippocampal seizure onsets are localized by stereoelectroencephalography.

OBJECTIVE: Selective laser amygdalohippocampotomy (SLAH) using magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is emerging as a treatment option for drug-resistant mesial temporal lobe epilepsy (MTLE). SLAH is less invasive than open resection, but there are limited series reporting its safety and efficacy, particularly in patients without clear evidence of mesial temporal sclerosis (MTS). METHODS: We report seizure outcomes and complications in our first 30 patients who underwent SLAH for drug-resistant MTLE between January 2013 and December 2016. We compare patients who required stereoelectroencephalography (SEEG) to confirm mesial temporal onset with those treated based on imaging evidence of MTS. RESULTS: Twelve patients with SEEG-confirmed, non-MTS MTLE and 18 patients with MRI-confirmed MTS underwent SLAH. MTS patients were older (median age 50 vs 30 years) and had longer standing epilepsy (median 40.5 vs 5.5 years) than non-MTS patients. Engel class I seizure freedom was achieved in 7 of 12 non-MTS patients (58%, 95% confidence interval [CI] 30%-86%) and 10 of 18 MTS patients (56%, 95% CI 33%-79%), with no significant difference between groups (odds ratio [OR] 1.12, 95% CI 0.26-4.91, P = .88). Length of stay was 1 day for most patients (range 0-3 days). Procedural complications were rare and without long-term sequelae. SIGNIFICANCE: We report similar rates of seizure freedom following SLAH in patients with MTS and SEEG-confirmed, non-MTS MTLE. Consistent with early literature, these rates are slightly lower than typically observed with surgical resection (60%-80%). However, SLAH is less invasive than open surgery, with shorter hospital stays and recovery, and severe procedural complications are rare. SLAH may be a reasonable first-line surgical option for patients with both MTS and SEEG confirmed, non-MTS MTLE.

The phenotype of bilateral hippocampal sclerosis and its management in "real life" clinical settings.

OBJECTIVE: There is little detailed phenotypic characterization of bilateral hippocampal sclerosis (HS). We therefore conducted a multicenter review of people with pharmacoresistant epilepsy and bilateral HS to better determine their clinical characteristics. METHODS: Databases from 11 EPIGEN centers were searched. For identified cases, clinicians reviewed the medical notes, imaging, and electroencephalographic (EEG), video-EEG, and neuropsychometric data. Data were irretrievably anonymized, and a single database was populated to capture all phenotypic information. These data were compared with phenotyped cases of unilateral HS from the same centers. RESULTS: In total, 96 patients with pharmacoresistant epilepsy and bilateral HS were identified (43 female, 53 male; age range = 8-80 years). Twenty-five percent had experienced febrile convulsions, and 27% of patients had experienced status epilepticus. The mean number of previously tried antiepileptic drugs was 5.32, and the average number of currently prescribed medications was 2.99; 44.8% of patients had cognitive difficulties, and 47.9% had psychiatric comorbidity; 35.4% (34/96) of patients continued with long-term medical therapy alone, another 4 being seizure-free on medication. Sixteen patients proceeded to, or were awaiting, neurostimulation, and 11 underwent surgical resection. One patient was rendered seizure-free postresection, with an improvement in seizures for 3 other cases. By comparison, of 201 patients with unilateral HS, a significantly higher number (44.3%) had febrile convulsions and only 11.4% had experienced status epilepticus. Importantly, 41.8% (84/201) of patients with unilateral HS had focal aware seizures, whereas such seizures were less frequently observed in people with bilateral HS, and were never observed exclusively (P = .002; Fisher's exact test). SIGNIFICANCE: The current work describes the phenotypic spectrum of people with pharmacoresistant epilepsy and bilateral HS, highlights salient clinical differences from patients with unilateral HS, and provides a large platform from which to develop further studies, both epidemiological and genomic, to better understand etiopathogenesis and optimal treatment regimes in this condition.

Genetic Testing in Pediatric Epilepsy.

PURPOSE OF REVIEW: This article summarizes the emerging landscape of pediatric epilepsy, highlighting genetic contributions, and reviews approaches to genetic evaluation for pediatric epilepsy in this context. RECENT FINDINGS: Advances in understanding the genetic basis for epilepsy over the last several years have been due in large part to the identification of de novo genetic variation underlying sporadic severe epilepsy in children; the genetic underpinnings of the more common epilepsies remain largely unknown. Next-generation sequencing approaches have been added to the repertoire of clinical tests for the evaluation of pediatric epilepsy, improving our ability to make positive diagnoses. Yields of over 50% are now being reported in selected groups of patients. Genetic variation contributing to the risk for pediatric epilepsy spans continua of scale and influence. The highest yield of genetic testing is currently in children with sporadic severe epilepsy caused by de novo variation. The approach to genetic evaluation and interpretation of results requires an understanding of (1) the epilepsy phenotype and (2) the particular advantages and limitations of the different genetic tests available. Our understanding of genetic variation will continue to improve over time and "negative" results are best conceptualized as "unresolved" or "negative for now."