The incidence of SUDEP

Multipsychiatric Comorbidity in People With Epilepsy Compared With People Without Epilepsy: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Persons with epilepsy (PwE) have a higher risk of developing psychiatric comorbidities compared with the general population. There is limited knowledge about the prevalence of multiple psychiatric conditions in PwE. We summarize the current evidence on the prevalence of multipsychiatric comorbidities in PwE compared with persons without epilepsy.

METHODS

A systematic review of multipsychiatric comorbidities in PwE compared with persons without epilepsy was performed, and the results were reported using the Preferred Reporting Items of Systematic Reviews and Meta-analyses reporting standards. The search was conducted from January 1945 to June 2023 in Ovid MEDLINE. Embase, and PsycINFO, using the search terms related to "epilepsy," "psychiatric comorbidity," and "multimorbidity," combined with psychiatric disorders. Abstracts were reviewed in duplicate, and data were independently extracted using standard proforma. Data describing multipsychiatric comorbidities in PwE compared with persons without epilepsy were recorded. Descriptive statistics and, when feasible, meta-analyses are presented. The risk of bias of the studies was assessed using the Newcastle-Ottawa Scale and the International League Against Epilepsy tool.

RESULTS

A total of 12,841 records were identified from the systematic database search, and 15 studies met the eligibility criteria. All included studies were deemed high-quality in risk of bias according to both tools. The prevalence of multipsychiatric comorbidity was greater in persons with compared with those without epilepsy. The pooled prevalence of concomitant depression and anxiety disorder in PwE in 2 population-based studies was 15 of 163 (9.2%), which was significantly higher than 250 of 10,551 (2.4%) in patients without epilepsy (odds ratio [OR] 3.7, 95% CI 2.1-6.5, p-value <0.001, I2 = 0%, Cochran Q p-value for heterogeneity = 0.84). In 2 hospital-based studies, the prevalence of concomitant depression and attention-deficit/hyperactivity disorder in PwE (14/97, 14.4%) was significantly higher than in patients without epilepsy (5/126, 3.9%), with an OR 5.2 (95% CI 1.8-15.0, p-value = 0.002, I2 = 0%, Cochran Q p-value for heterogeneity = 0.79).

DISCUSSION

PwE experience elevated levels of multipsychiatric comorbidity compared with those without epilepsy. However, very few studies have empirically evaluated the extent of multipsychiatric comorbidity in PwE compared with persons without epilepsy nor their associations and consequences to prognosis in PwE.

Revascularization Therapies for Ischemic Stroke and Association With Risk of Epilepsy: A Danish Nationwide Register-Based Study

BACKGROUND

The association between stroke revascularization therapies and poststroke epilepsy is only sparsely investigated, and results are conflicting. The aim of this study is to investigate whether stroke revascularization therapies are associated with different risks of poststroke epilepsy.

METHODS AND RESULTS

We conducted a nationwide, register-based, propensity score-matched cohort study. We identified 40 816 patients admitted with a first ischemic stroke and no prior history of epilepsy in Denmark between January 1, 2011, and December 16, 2018. Of these, 6541 were treated with thrombolysis, 379 with thrombectomy, and 1005 with both thrombolysis and thrombectomy. The 3 treatment groups were each matched 1:1 to patients with stroke not treated with revascularization. Exact matching was done for sex, while propensity scores included information on stroke severity, cortical involvement, age, comorbidities, and socioeconomic parameters. Outcome was any diagnosis of epilepsy. We used Cox regressions to estimate adjusted hazard ratios (HRs) of epilepsy after ischemic stroke. Compared with matched patients with ischemic stroke not receiving revascularization treatment, patients who received thrombolysis alone had 32% lower risk of epilepsy (adjusted HR, 0.68 [95% CI, 0.57-0.81]) and patients who received thrombolysis and thrombectomy had 45% lower risk of epilepsy (adjusted HR, 0.55 [95% CI, 0.41-0.73]). Thrombectomy alone was not associated with significantly lower risk of epilepsy compared with matched patients with ischemic stroke not receiving revascularization therapy (adjusted HR, 0.78 [95% CI, 0.57-1.29]).

CONCLUSIONS

Thrombolysis alone and in combination with thrombectomy in ischemic stroke was associated with lower risk of epilepsy, whereas thrombectomy alone was not associated with lower risk of epilepsy.

Comprehensive scoping review of fenfluramine's role in managing generalized tonic-clonic seizures in developmental and epileptic encephalopathies

Developmental and epileptic encephalopathies (DEEs) are characterized by pharmacoresistant seizures and developmental delay. Patients with DEEs experience multiple seizure types, including tonic-clonic seizures (TCS) that can be generalized tonic-clonic (GTCS) or focal evolving to bilateral tonic-clonic (FBTCS). Fenfluramine (FFA) has demonstrated efficacy in reduction of TCS in patients with Dravet syndrome (DS), Lennox-Gastaut syndrome (LGS), and other DEEs. Using the PRISMA-ScR (Preferred Reporting Items for Systematic Review and Meta-Analyses extension for Scoping Review) guidelines, we performed a scoping review to describe changes in TCS in patients treated with FFA. A comprehensive search of five literature databases was conducted up to February 14, 2023. Studies were included if they reported change in GTCS or TCS (but not FBTCS) after treatment with FFA in patients with DEEs. Duplicate patients and studies with unclear efficacy data were excluded. Fourteen of 422 studies met the eligibility criteria. Data extracted and evaluated by expert clinicians identified 421 unique patients with DS (in nine studies), CDKL5 deficiency disorder, SCN8A-related disorder, LGS, SCN1B-related disorder, and other DEEs. The median percent reduction in GTCS or TCS from baseline was available in 10 studies (n = 328) and ranged from 47.2% to 100%. Following FFA treatment, 10 studies (n = 144) reported ≥50% reduction in GTCS or TCS from baseline in 72% of patients; in nine of those (n = 112), 54% and 29% of patients achieved ≥75% and 100% reduction in GTCS or TCS from baseline, respectively. Overall, this analysis highlighted improvements in GTCS or TCS frequency when patients were treated with FFA regardless of the DEE evaluated. Future studies may confirm the impact of FFA on TCS reduction and on decreased premature mortality risk (including sudden unexpected death in epilepsy), improvement in comorbidities and everyday executive function, decreased health care costs, and improvement in quality of life.

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Hypothalamic-Pituitary-Adrenal Axis Dysfunction Elevates SUDEP Risk in a Sex-Specific Manner

Epilepsy is often comorbid with psychiatric illnesses, including anxiety and depression. Despite the high incidence of psychiatric comorbidities in people with epilepsy, few studies address the underlying mechanisms. Stress can trigger epilepsy and depression. Evidence from human and animal studies supports that hypothalamic-pituitary-adrenal (HPA) axis dysfunction may contribute to both disorders and their comorbidity ( Kanner, 2003). Here, we investigate if HPA axis dysfunction may influence epilepsy outcomes and psychiatric comorbidities. We generated a novel mouse model (Kcc2/Crh KO mice) lacking the K+/Cl- cotransporter, KCC2, in corticotropin-releasing hormone (CRH) neurons, which exhibit stress- and seizure-induced HPA axis hyperactivation ( Melon et al., 2018). We used the Kcc2/Crh KO mice to examine the impact on epilepsy outcomes, including seizure frequency/burden, comorbid behavioral deficits, and sudden unexpected death in epilepsy (SUDEP) risk. We found sex differences in HPA axis dysfunction's effect on chronically epileptic KCC2/Crh KO mice seizure burden, vulnerability to comorbid behavioral deficits, and SUDEP. Suppressing HPA axis hyperexcitability in this model using pharmacological or chemogenetic approaches decreased SUDEP incidence, suggesting that HPA axis dysfunction may contribute to SUDEP. Altered neuroendocrine markers were present in SUDEP cases compared with people with epilepsy or individuals without epilepsy. Together, these findings implicate HPA axis dysfunction in the pathophysiological mechanisms contributing to psychiatric comorbidities in epilepsy and SUDEP.

[Incidence of sudden death in epilepsy (SUDEP): update and limitations]

BACKGROUND

Sudden unexpected death in epilepsy (SUDEP) is in most cases probably due to a fatal complication of tonic-clonic seizures and plays a significant role in the premature mortality of individuals with epilepsy. The reported risks of SUDEP vary considerably depending on the study population, so that an up-dated systematic review of SUDEP incidence including most recent studies is required to improve the estimated SUDEP risk and the counseling of individuals with epilepsy.

OBJECTIVE

To provide an overview of the current research landscape concerning SUDEP incidence across different patient populations and discuss potential conclusions and existing limitations.

MATERIAL AND METHODS

A systematic literature review on SUDEP incidence was conducted in MEDLINE and EMBASE, supplemented by a manual search in June 2023. Out of a total of 3324 publications, 50 were reviewed for this study.

RESULTS

The analyzed studies showed significant heterogeneity concerning cohorts, study design and data sources. Studies conducted without specific criteria and relying on comprehensive registers indicated an incidence of 0.78-1.2 per 1000 patient-years. Research providing incidences across various age groups predominantly show an increase with age, peaking in middle age.

DISCUSSION

Due to varying methods of data collection and incidence calculation, comparing between studies is challenging. The association with age might be due to an underrepresentation of children, adolescents and patients over 60 years.

CONCLUSION

Considering all age groups and types of epilepsy it is estimated that about 1 in 1000 individuals with epilepsy dies of SUDEP annually. With an assumed epilepsy prevalence of 0.6% in Germany, this could lead to more than one SUDEP case daily. Standardization of research methods is essential to gain more profound insights.

Second antiseizure medication monotherapy in patients with adult-onset epilepsy: A register-based analysis

OBJECTIVE

Revision of therapy is fundamental in epilepsy care, since only half of patients achieve seizure freedom and tolerate the first antiseizure medication (ASM). We studied the selection and retention of second antiseizure medication monotherapy in adults who discontinued treatment with one of the three most frequently prescribed first ASMs, and the impact of age or brain comorbidities.

METHODS

Using Swedish national registers, we conducted a population-based, retrospective cohort study from 2007 to 2019 on patients age ≥ 30 at the epilepsy diagnosis that had switched to a second monotherapy after the three most common initial monotherapies (n = 7369). Retention rates (RR) were estimated via Kaplan-Meier. Discontinuation of the second monotherapy was defined as 12-month prescription gap or initiation of a third ASM. Analyses were stratified by sex, age, and presence of stroke or dementia.

RESULTS

The three most commonly prescribed second ASMs were carbamazepine, levetiracetam, and lamotrigine. The 1-year retention rate was 63-76% in all patients. For groups with stroke or dementia, the maximal 1-year RRs were 77% and 87%, respectively. After five years, retention rates ranged from 12% to 39%. There were no major differences between ASMs, apart from in patients discontinuing carbamazepine, where lamotrigine had a superior retention compared to levetiracetam as second monotherapy.

SIGNIFICANCE

The three most often prescribed second ASMs seem to be suitable treatment options according to present guidelines. The second ASMs' retention rates were initially high in all studied patient groups but dropped to approximately the expected proportion of second monotherapy responders over the next five years. This suggests that therapy revision could be expedited.

Cardiac arrhythmia and epilepsy genetic variants in sudden unexpected death in epilepsy

Introduction

Sudden Unexpected Death in Epilepsy (SUDEP) is the leading epilepsy-related cause of death, affecting approximately 1 per 1,000 individuals with epilepsy per year. Genetic variants that affect autonomic function, such as genes associated with cardiac arrhythmias, may predispose people with epilepsy to greater risk of both sudden cardiac death and SUDEP. Advances in next generation sequencing allow for the exploration of gene variants as potential biomarkers.

Methods

Genetic testing for the presence of cardiac arrhythmia and epilepsy gene variants was performed via genetic panels in 39 cases of SUDEP identified via autopsy by the Ontario Forensic Pathology Service. Variants were summarized by in-silico evidence for pathogenicity from 4 algorithms (SIFT, PolyPhen-2, PROVEAN, Mutation Taster) and allele frequencies in the general population (GnomAD). A maximum credible population allele frequency of 0.00004 was calculated based on epilepsy prevalence and SUDEP incidence to assess whether a variant was compatible with a pathogenic interpretation.

Results

Median age at the time of death was 33.3 years (range: 2, 60). Fifty-nine percent (n=23) were male. Gene panels detected 62 unique variants in 45 genes: 19 on the arrhythmia panel and 26 on the epilepsy panel. At least one variant was identified in 28 (72%) of decedents. Missense mutations comprised 57 (92%) of the observed variants. At least three in silico models predicted 12 (46%) cardiac arrhythmia panel missense variants and 20 (65%) epilepsy panel missense variants were pathogenic. Population allele frequencies were <0.00004 for 11 (42%) of the cardiac variants and 10 (32%) of the epilepsy variants. Together, these metrics identified 13 SUDEP variants of interest.

Discussion

Nearly three-quarters of decedents in this SUDEP cohort carried variants in comprehensive epilepsy or cardiac arrhythmia gene panels, with more than a third having variants in both panels. The proportion of decedents with cardiac variants aligns with recent studies of the disproportionate cardiac burden the epilepsy community faces compared to the general population and suggests a possible cardiac contribution to epilepsy mortality. These results identified 13 priority targets for future functional studies of these genes potential role in sudden death and demonstrates the necessity for further exploration of potential genetic contributions to SUDEP.

Personalization of SUDEP risk: A survey of transient subclinical comorbid changes

OBJECTIVE

Preclinical data report within subject modifiable ailments emerge weeks prior to SUDEP, including sleep disorders and cardiorespiratory changes; findings which support anecdotal clinical data. Here, we bridge preclinical findings with future clinical/preclinical studies, and survey whether caretakers or family members of victims noticed transient changes prior to SUDEP. The aim of this pilot study is to identify potential modifiable changes that may synergistically increase SUDEP risk for future research.

METHODS

A mobile electronic survey was posted on SUDEP community websites. The survey queried whether changes in seizures, sleep, physical well-being, emotional well-being, cognition, breathing, or heart rate were noticed before SUDEP.

RESULTS

The most profound finding was that 85% of victims had multiple transient ailments prior to SUDEP. Changes in seizures (28/54), and sleep (30/58) occurred in more than 50% of the victims and represent the most influential changes identified. The second and third most influential changes were a reduction in physical well-being (25/57) and emotional well-being (26/56). Changes were observed within the last two months of life in approximately one third of the cases, and more than four months prior to SUDEP in approximately one third of cases, indicating a potential time frame for proactive preventative strategies. Respondents also noted changes in cognition (16/55), breathing (9/54) or heart rate (8/55). Data indicate these changes may be associated with increased SUDEP risk within subject. Study limitations include the responses were based on memory, there was a potential for data to be over reported, and caretakers were not prompted to observe changes a priori, thus some existing changes may have gone unnoticed.

SIGNIFICANCE

Data support the preclinical findings that transient, subclinical (i.e., not severe enough to require medical intervention), modifiable ailments may increase risk of SUDEP. This suggests that just as an epilepsy type can change over a lifetime and epilepsy type-specific treatments can reduce SUDEP risk, further personalization of SUDEP risk will improve our understanding as to whether variables contribute to risk differently across lifespan. Thus, with a dynamic capacity to change, differing factors may contribute to the distribution of risk probability within an individual at any given time. Understanding whether different combinations of transient changes are specific to epilepsy type, age, or sex needs to be determined to move the field forward in hopes of developing a personalized approach to preventative strategies.

Type, Etiology, and Duration of Epilepsy as Risk Factors for SUDEP: Further Analyses of a Population-Based Case-Control Study

BACKGROUND AND OBJECTIVES

We conducted a nationwide case-control study in Sweden to investigate the risk of sudden unexpected death in epilepsy (SUDEP) in relation to epilepsy duration, epilepsy type, and etiology in combination with occurrence and frequency of tonic-clonic seizures (TCS) and nocturnal TCS.

METHODS

The study comprised 255 SUDEP cases and 1,148 epilepsy controls. Clinical information was obtained from medical records. The association between SUDEP and risk factors was estimated by odds ratios (ORs) with 95% CIs calculated by conditional logistic regression to account for matching by sex and calendar time.

RESULTS

The risk of SUDEP was elevated in people with focal (OR 1.48, 95% CI 1.00-2.20), generalized and focal (OR 3.51, 95% CI 1.55-7.96), or unknown (OR 2.43, 95% CI 1.29-4.57) vs generalized epilepsy type. Increased risk of SUDEP was also observed in relation to epilepsy with traumatic causes (OR 2.27, 95% CI 1.33-3.89 vs genetic etiology) or short duration (OR 1.71, 95% CI 1.01-2.87 for 0-5 vs 6-15 years duration). Among those with 1-3 TCS during the preceding year, structural epilepsy etiology was associated with a more than 10-fold increase 10.84 (4.85-24.27) in SUDEP risk compared with people with genetic epilepsy without TCS. The risk with ≥4 TCS the preceding year was similar among those with generalized and focal epilepsies. Those with ≥4 TCS had an OR of 210.73 (95% CI 28.40-∞) during years 0-5 compared with those free from TCS and an epilepsy duration of 6-15 years. The combination of short epilepsy duration (0-5 years) and nocturnal TCS conferred an OR of 45.99 (95% CI 12.19-173.61) compared with having longer duration (6-15 years) and being free from nocturnal TCS.

DISCUSSION

Although certain etiologies, such as post-traumatic epilepsy, seem to entail a higher SUDEP risk, our data indicate that frequent and nocturnal TCS carry a similar level of risk whether focal or generalized from onset. The tonic-clonic part of the seizure seems to be decisive for the fatal outcome. SUDEP risk associated with TCS is highest during the first years after the epilepsy diagnosis which calls for effective TCS treatment and vigilance from the onset of diagnosis.

Sudden unexpected death in epilepsy disclosure causes anxiety in patients with epilepsy: a Chinese questionnaire survey

Background and objective

Sudden unexpected death in epilepsy (SUDEP) has been regarded as a leading cause of premature death in patients with epilepsy (PWE). Although patients, relatives and caregivers have the right to be informed of SUDEP, neurologists prefer not to release the facts for fear of associated anxiety. In the study, a Chinese questionnaire survey was carried out to elucidate effect of SUDEP disclosure on anxiety in PWE and variables determining the anxiety of patients and provided suggestions for SUDEP disclosure.

Methods

A survey study in China was conducted. We recruited 305 PWE from 3 tertiary epilepsy centers who attended outpatient clinic from December 2021 to February 2022. Two hundred and thirty-two PWE completed the screening evaluation, survey and Hamilton anxiety rating scale (HAMA) twice with 171 PWE completing third HAMA at follow-up. HAMA scores at baseline, T1, T2 were compared using analysis of variance and dependent samples t-test. The variables related to anxiety were screened out by univariate analysis and used for multivariate logistic regression.

Result

We found 127 (54.7%) among the 232 participants experienced anxiety after SUDEP disclosure. HAMA scores at T1 were significantly higher than at baseline and T2, while there was no statistical difference between baseline and T2. Medical insurance, seizure severity, and whether the PWE supported SUDEP being disclosed to their relatives and caregivers only were associated with the occurrence of anxiety.

Conclusion

SUDEP disclosures may cause short-term acute anxiety, but have no long-term effects in PWE. Acute anxiety caused by SUDEP disclosure may be more common in PWE with NCMI and severe seizures. Meanwhile, compared with indirect SUDEP disclosure to their relatives and caregivers, direct SUDEP disclosure to PWE reduces the risk of anxiety. Recommendations are provided to avoid anxiety caused by SUDEP disclosure.

Further advances in epilepsy

In 2017, one of us reviewed advances in epilepsy (Manford in J Neurol 264:1811-1824, 2017). The current paper brings that review up to date and gives a slight change in emphasis. Once again, the story is of evolution rather than revolution. In recognition that most of our current medications act on neurotransmitters or ion channels, and not on the underlying changes in connectivity and pathways, they have been renamed as antiseizure (ASM) medications rather than antiepileptic drugs. Cenobamate is the one newly licensed medication for broader use in focal epilepsy but there have been a number of developments for specific disorders. We review new players and look forward to new developments in the light of evolving underlying science. We look at teratogenicity; old villains and new concerns in which clinicians play a vital role in explaining and balancing the risks. Medical treatment of status epilepticus, long without evidence, has benefitted from high-quality trials to inform practice; like buses, several arriving at once. Surgical treatment continues to be refined with improvements in the pre-surgical evaluation of patients, especially with new imaging techniques. Alternatives including stereotactic radiotherapy have received further focus and targets for palliative stimulation techniques have grown in number. Individuals' autonomy and quality of life continue to be the subject of research with refinement of what clinicians can do to help persons with epilepsy (PWE) achieve control. This includes seizure management but extends to broader considerations of human empowerment, needs and desires, which may be aided by emerging technologies such as seizure detection devices. The role of specialist nurses in improving that quality has been reinforced by specific endorsement from the International League against Epilepsy (ILAE).

Derivation and validation of a new prediction model for sudden unexpected death in epilepsy based on a longitudinal prospective population-based cohort

OBJECTIVE

We conducted a population-based, prospective cohort study with a large sample size in Ningxia Province of the Northwest, a rural area in China, by developing a model to specifically assess risk factors of sudden unexpected death in epilepsy (SUDEP) in people with convulsive epilepsy by clinical variables.

METHODS

Participants with convulsive epilepsy were recruited from January 1, 2008, to April 28, 2022, in rural Northwest China. They received regular assessments and management of epilepsy at the primary healthcare level and were followed up monthly. Information on the cause of death and relevant clinical details was obtained from death certificates or neurologist-conducted verbal autopsies. Survival analysis was employed to identify potential risk factors associated with SUDEP.

RESULTS

Five variables were independently associated with SUDEP: generalized tonic-clonic seizures (GTCS) with ≥1 attack during the preceding month, GTCS with >3 attacks during the preceding year, body mass index (BMI) ≥24, age of onset ≤14 years, and duration >20 years. The area under receiver operator characteristic (ROC) curve (AUC) value (95% CI) of the model was 0.789 (0.735-0.843) in the derivation dataset and 0.830 (0.758-0.902) in the validation dataset. There was agreement between the observed and predicted probabilities of SUDEP.

CONCLUSIONS

This study establishes that high GTCS frequency, early age of onset, long duration of epilepsy, and being overweight are associated with an increased risk of SUDEP in individuals with convulsive epilepsy. The study also developed and validated a personalized prediction model to accurately assess the risk of SUDEP.

Is anti-seizure medication the culprit of SUDEP?

BACKGROUND

Heart rate variability (HRV) reduction is a potential biomarker for sudden cardiac death. This study aimed to study the effects of anti-seizure medications (ASMs), adjusted with reported factors associated with sudden unexpected death in epilepsy (SUDEP) on HRV parameters.

METHODS

We recruited patients who were admitted in our epilepsy monitoring unit between January 2013 and December 2021. Two 5-min electrocardiogram epochs during wakefulness and sleep were selected in each patient. HRV analysis with Python® software was performed. The imputed datasets were used for linear regression analysis to assess association between each ASM item and all HRV parameters. The effects of ASM on HRV parameters were subsequently adjusted with the significant clinical characteristics and the concomitant use of other ASMs, respectively.

RESULTS

Carbamazepine (CBZ), levetiracetam (LEV), lamotrigine (LTG), and clonazepam (CZP) were statistically significantly associated with changes of sleep HRV parameters. Only CBZ showed negative effects with reduction in HRV, evidenced as lower standard deviation of RR interval (SDNN), even when adjusted with concomitant use of other ASMs (p = 0.045) and had a trend of significance when adjusted with significant clinical characteristics of concurrent taking of beta-blocker drug (p = 0.052). LEV and CZP showed opposite effects with increased HRV even when adjusted with significant clinical characteristics and the concomitant use of other ASMs.

CONCLUSIONS

CBZ showed negative effects on HRV. We proposed that CBZ should be cautiously used in patients with known risks for SUDEP. In addition, HRV assessment should be performed prior to commencing CBZ and re-performed in follow-up in cases of prolonged use.

Nocturnal seizure detection: What are the needs and expectations of adults with epilepsy receiving secondary care?

INTRODUCTION

Seizure detection devices (SDDs) may lower the risk of sudden unexpected death in epilepsy (SUDEP) and provide reassurance to people with epilepsy and their relatives. We aimed to explore the perspectives of those receiving secondary care on nocturnal SDDs and epilepsy in general.

MATERIALS AND METHODS

We recruited adults with tonic or tonic-clonic seizures who had at least one nocturnal seizure in the preceding year. We used semi-structured interviews and questionnaires to explore their views on SDDs and their experiences of living with epilepsy. None of the participants had any previous experience with SDDs. We analyzed the data using qualitative content analysis.

RESULTS

Eleven participants were included with a nocturnal seizure frequency ranging from once every few weeks to less than once a year. Some participants experienced little burden of disease, whereas others were extremely impaired. Opinions on the perceived benefit of seizure detection varied widely and did not always match the clinical profile. Some participants with high SUDEP risk displayed no interest at all, whereas others with a low risk for unattended seizures displayed a strong interest. Reasons for wanting to use SDDs included providing reassurance, SUDEP prevention, and improving night rest. Reasons for not wanting to use SDDs included not being able to afford it, having to deal with false alarms, not having anyone to act upon the alarms, having a relative that will notice any seizures, not feeling like the epilepsy is severe enough to warrant SDD usage or not trusting the device.

CONCLUSIONS

The interest in nocturnal seizure detection varies among participants with low seizure frequencies and does not always match the added value one would expect based on the clinical profile. Further developments should account for the heterogeneity in user groups.

Sudden unexpected death in epilepsy: A critical view of the literature

Sudden unexpected death in epilepsy (SUDEP) is a sudden, unexpected, witnessed or unwitnessed, non-traumatic and non-drowning death, occurring in benign circumstances, in an individual with epilepsy, with or without evidence for a seizure and excluding documented status epilepticus in which postmortem examination does not reveal other causes of death. Lower diagnostic levels are assigned when cases met most or all of these criteria, but data suggested more than one possible cause of death. The incidence of SUDEP ranged from 0.09 to 2.4 per 1000 person-years. Differences can be attributed to the age of the study populations (with peaks in the 20-40-year age group) and the severity of the disease. Young age, disease severity (in particular, a history of generalized TCS), having symptomatic epilepsy, and the response to antiseizure medications (ASMs) are possible independent predictors of SUDEP. The pathophysiological mechanisms are not fully known due to the limited data available and because SUDEP is not always witnessed and has been electrophysiologically monitored only in a few cases with simultaneous assessment of respiratory, cardiac, and brain activity. The pathophysiological basis of SUDEP may vary according to different circumstances that make that particular seizure, in that specific moment and in that patient, a fatal event. The main hypothesized mechanisms, which could contribute to a cascade of events, are cardiac dysfunction (included potential effects of ASMs, genetically determined channelopathies, acquired heart diseases), respiratory dysfunction (included postictal arousal deficit for the respiratory mechanism, acquired respiratory diseases), neuromodulator dysfunction, postictal EEG depression and genetic factors.

Chronic evoked seizures in young pre-symptomatic APP/PS1 mice induce serotonin changes and accelerate onset on Alzheimer's disease-related neurpathology

OBJECTIVE

People with early-onset Alzheimer's disease (AD) are at elevated seizure risk. Further, chronic seizures in pre-symptomatic stages may disrupt serotonin pathway-related protein expression, precipitating the onset of AD-related pathology and burden of neuropsychiatric comorbidities.

METHODS

2-3-month-old APP/PS1, PSEN2-N141I, and transgenic control mice were sham or corneal kindled for 2 weeks to model chronic seizures. Seizure-induced changes in glia, serotonin pathway proteins, and amyloid beta; levels in hippocampus and prefrontal cortex were quantified.

RESULTS

APP/PS1 mice experienced worsened mortality versus kindled Tg- controls. APP/PS1 females were also more susceptible to chronic kindled seizures. These changes correlated with a marked downregulation of hippocampal tryptophan hydroxylase 2 and monoamine oxidase A protein expression compared to controls; these changes were not detected in PSEN2-N141I mice. Kindled APP/PS1 mice exhibited amyloid beta; overexpression and glial overactivity without plaque deposition. PSEN2 protein expression was AD model-dependent.

SIGNIFICANCE

Seizures evoked in pre-symptomatic APP/PS1 mice promotes premature mortality in the absence of pathological amyloid deposition. Disruptions in serotonin pathway metabolism are associated with increased glial reactivity and PSEN2 downregulation without amyloid beta; deposition. This study provides the first direct evidence that seizures occurring prior to amyloid beta, plaque accumulation worsen disease burden in an AD genotype-specific manner.

Genetics and SUDEP: Challenges and Future Directions

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related deaths in children and adults with epilepsy. The incidence of SUDEP in children and adults is equal, approximately 1.2 per 1000-person years. Although inroads have been made in our understanding of SUDEP, its pathophysiology remains unknown. The most important risk factor for SUDEP is the presence of tonic-clonic seizures. Recently there has been growing interest in the contribution of genetic risk factors to SUDEP deaths. Pathogenic variants in epilepsy-related and cardiac genes have been found in some cases of SUDEP post-mortem. Pleiotropy may occur in which a single gene when altered may cause multiple phenotypes (i.e., epilepsy and cardiac arrhythmia). Recently it has been shown that some developmental and epileptic encephalopathies (DEEs) may also be at heightened risk of SUDEP. In addition, polygenic risk has been postulated to effect SUDEP risk with current models evaluating the additive effect of variants in multiple genes. However, the mechanisms underpinning polygenic risk in SUDEP are likely more complex than this. Some preliminary studies also highlight the feasibility of detecting genetic variants in brain tissue post-mortem. Despite the advances in the field of SUDEP genetics, the use of molecular autopsy remains underutilized in SUDEP cases. Several challenges exist concerning genetic testing post-mortem in SUDEP cases, such as interpretation, cost of testing, and availability. In this focused review, we highlight the current landscape of genetic testing in SUDEP cases, its challenges, and future directions.

Impact of psychiatric comorbidities on the treatment of epilepsies in adults

INTRODUCTION

Epilepsy is often accompanied by psychiatric comorbidities and the management of epilepsy in these patients presents unique challenges due to the interplay between the underlying neurological condition and the psychiatric symptoms and the combined use of multiple medications.

AREAS COVERED

This paper aims to explore the complexities associated with managing epilepsy in the presence of psychiatric comorbidities, focusing on the impact of psychiatric disorders on epilepsy treatment strategies and the challenges posed by the simultaneous administration of multiple medications.

EXPERT OPINION

Patients with epilepsy and psychiatric comorbidities seem to present with a more severe form of epilepsy that is resistant to drug treatments and burdened by an increased morbidity and mortality. Whether prompt treatment of psychiatric disorders can influence the long-term prognosis of the epilepsy is still unclear as well as the role of specific treatment strategies, such as neuromodulation, in this group of patients. Clinical practice recommendations and guidelines will prompt the development of new models of integrated care to be implemented.

Mortality in children with epilepsy: Cohort study using the clinical practice research datalink

OBJECTIVE

To estimate Mortality Rate (MR) in UK children with epilepsy (CWE) compared to children without epilepsy (CWOE), describe causes of death, determine Mortality Rate Ratios (MRRs) for cause-specific mortality, and to analyse the contribution of co-morbidities (respiratory disease, neoplasm, and congenital disorders) to mortality rate.

METHOD

Retrospective cohort study of children born between 1998 and 2017, using linked data from the Clinical Practice Research Datalink Gold (Set 18). Epilepsy diagnoses were identified using previously validated codes. Causes of death were defined as natural or non-natural. Epilepsy-related deaths in CWE were those where underlying or contributing cause of death was epilepsy, status epilepticus, seizures, ill-defined/unknown cause or sudden death. We used Cox proportional hazard analysis to investigate associations of epilepsy and mortality.

RESULTS

There were 1,191,304 children followed for 13,994,916 person-years (median: 12) if which 9665 (0.8%) had epilepsy. Amongst CWE, 3.4% died. MR of CWE was 4.1 (95%CI 3.7-4.6)/1,000 person-years. CWE had an increased adjusted all-cause mortality (MRR 50.9,95%CI 44.8-57.7) compared to CWOE. Amongst the 330 deaths in CWE, 323 (98%) were natural, 7 (2%) non-natural, 80 (24%) epilepsy-related. MRR of non-natural deaths was 2.09 (95%CI 0.92,4.74, p = 0.08).

SIGNIFICANCE

Amongst CWE, 3.4% died during the study period. All-cause mortality rate in CWE was 4/1,000 person-years representing a fifty-fold increased mortality risk, after taking into account sex and socioeconomic status, compared to similarly aged children who did not have epilepsy. Causes of death mostly were not seizure-related. Non-natural death in CWE was uncommon.

Brain Connectivity Correlates of Breathing and Cardiac Irregularities in SUDEP: A Resting-State fMRI Study

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of premature mortality among people with epilepsy. Evidence from witnessed and monitored SUDEP cases indicate seizure-induced cardiovascular and respiratory failures; yet, the underlying mechanisms remain obscure. SUDEP occurs often during the night and early morning hours, suggesting that sleep or circadian rhythm-induced changes in physiology contribute to the fatal event. Resting-state fMRI studies have found altered functional connectivity between brain structures involved in cardiorespiratory regulation in later SUDEP cases and in individuals at high-risk of SUDEP. However, those connectivity findings have not been related to changes in cardiovascular or respiratory patterns. Here, we compared fMRI patterns of brain connectivity associated with regular and irregular cardiorespiratory rhythms in SUDEP cases with those of living epilepsy patients of varying SUDEP risk, and healthy controls. We analysed resting-state fMRI data from 98 patients with epilepsy (9 who subsequently succumbed to SUDEP, 43 categorized as low SUDEP risk (no tonic-clonic seizures (TCS) in the year preceding the fMRI scan), and 46 as high SUDEP risk (>3 TCS in the year preceding the scan)) and 25 healthy controls. The global signal amplitude (GSA), defined as the moving standard deviation of the fMRI global signal, was used to identify periods with regular ('low state') and irregular ('high state') cardiorespiratory rhythms. Correlation maps were derived from seeds in twelve regions with a key role in autonomic or respiratory regulation, for the low and high states. Following principal component analysis, component weights were compared between the groups. We found widespread alterations in connectivity of precuneus/posterior cingulate cortex in epilepsy compared to controls, in the low state (regular cardiorespiratory activity). In the low state, and to a lesser degree in the high state, reduced anterior insula connectivity (mainly with anterior and posterior cingulate cortex) in epilepsy appeared, relative to healthy controls. For SUDEP cases, the insula connectivity differences were inversely related to the interval between the fMRI scan and death. The findings suggest that anterior insula connectivity measures may provide a biomarker of SUDEP risk. The neural correlates of autonomic brain structures associated with different cardiorespiratory rhythms may shed light on the mechanisms underlying terminal apnea observed in SUDEP.

Sudden unexpected death in epilepsy (SUDEP): A bibliometric analysis

OBJECTIVE

The literature on sudden unexpected death in epilepsy (SUDEP) has been evolving at a staggering rate. We conducted a bibliometric analysis of the SUDEP literature with the aim of presenting its structure, performance, and trends.

METHODS

The Scopus database was searched in April 2023 for documents explicitly detailing SUDEP in their title, abstract, or keywords. After the removal of duplicate documents, bibliometric analysis was performed using the R package bibliometrix and the program VOSviewer. Performance metrics were computed to describe the literature's annual productivity, most relevant authors and countries, and most important publications. Science mapping was performed to visualize the relationships between research constituents by constructing a country collaboration network, co-authorship network, keyword co-occurrence network, and document co-citation network.

RESULTS

A total of 2140 documents were analyzed. These documents were published from 1989 onward, with an average number of citations per document of 25.78. Annual productivity had been on the rise since 2006. Out of 6502 authors, five authors were in both the list of the ten most productive and the list of the ten most cited authors: Devinsky O, Sander JW, Tomson T, Ryvlin P, and Lhatoo SD. The USA and the United Kingdom were the most productive and cited countries. Collaborations between American authors and European authors were particularly rich. Prominent themes in the literature included those related to pathophysiology (e.g., cardiac arrhythmia, apnea, autonomic dysfunction), epilepsy characteristics (e.g., epilepsy type, refractoriness, antiseizure medications), and epidemiology (e.g., incidence, age, sex). Emerging themes included sleep, genetics, epilepsy refractoriness, and non-human studies.

SIGNIFICANCE

The body of literature on SUDEP is rich, fast-growing, and benefiting from frequent international collaborations. Some research themes such as sleep, genetics, and animal studies have become more prevalent over recent years.

The application of SUDEP in forensic diagnosis: a mini review

In the epilepsy population, the risk of sudden death from epilepsy is rare but is ~24 times greater than the risk of sudden death from other causes. Sudden unexpected death in epilepsy (SUDEP) has been widely recognized in clinical studies. Despite its significance as a cause of death, SUDEP is rarely used in forensic practice. This review focuses on the forensic characteristics of SUDEP, analyzed the reasons for its underuse in forensic practice, and illustrated the prospect of establishing uniform diagnostic criteria for sudden unexpected death in epilepsy and molecular anatomy in aiding forensic diagnosis.

Sudden unexpected death in epilepsy

PURPOSE OF REVIEW

Sudden unexpected death in epilepsy (SUDEP) is a leading cause of death in patients with epilepsy. This review highlights the recent literature regarding epidemiology on a global scale, putative mechanisms and thoughts towards intervention and prevention.

RECENT FINDINGS

Recently, numerous population-based studies have examined the incidence of SUDEP in many countries. Remarkably, incidence is quite consistent across these studies, and is commensurate with the recent estimates of about 1.2 per 1000 patient years. These studies further continue to support that incidence is similar across the ages and that comparable factors portend heightened risk for SUDEP. Fervent research in patients and animal studies continues to hone the understanding of potential mechanisms for SUDEP, especially those regarding seizure-induced respiratory dysregulation. Many of these studies and others have begun to lay out a path towards identification of improved treatment and prevention means. However, continued efforts are needed to educate medical professionals about SUDEP risk and the need to disclose this to patients.

SUMMARY

SUDEP is a devastating potential outcome of epilepsy. More is continually learned about risk and mechanisms from clinical and preclinical studies. This knowledge can hopefully be leveraged into preventive measures in the near future.

Adherence patterns in antiseizure medications influencing risk of sudden unexplained death in epilepsy: A data linkage study using dispensed prescriptions

OBJECTIVE

Medication adherence is considered an important risk factor for sudden unexpected death in epilepsy (SUDEP), although measurement accuracy is difficult. Using prescription dispensations, this study aims to estimate antiseizure medication (ASM) adherence and identify adherence patterns that influence epilepsy mortality.

METHODS

This is a retrospective cohort study of tertiary epilepsy outpatients seen at St Vincent's Hospital Melbourne, Victoria, Australia, from January 1, 2012 until December 31, 2017. Privacy-preserving data linkage with the Australian national prescription, death, and coroner's databases was performed. We fitted a four-cluster longitudinal group-based trajectory model for ASM adherence from recurring 90-day windows of prescription dispensations during a 3-year "landmark period" from January 1, 2012 to December 31, 2014, using the AdhereR package. We estimated the risk of SUDEP and all-cause death for each adherence pattern during an "observation period" from January 1, 2015 to December 31, 2017. The Cox proportional hazards and logistic regression models were adjusted for age, sex, socioeconomic status, epilepsy duration, comorbidity, drug resistance, and inadequate seizure control.

RESULTS

One thousand one hundred eighty-seven participants were observed for a median of 3.2 years (interquartile range = 2.4-4.0 years). We observed 66 deaths with 10 SUDEP cases during the observation period. We identified four patterns of ASM adherence: good, 51%; declining, 24%; poor, 16%; and very poor, 9%. Declining adherence was associated with an increased risk for SUDEP, with hazard ratio (HR) = 8.43 (95% confidence interval [CI] = 1.10-64.45) at 1 year and HR = 9.17 (95% CI = 1.16-72.21) at 3 years. Compared to no ASM therapeutic change, the addition of a second to fourth ASM offered increased protection against SUDEP in patients with continuing drug-resistant epilepsy.

SIGNIFICANCE

ASM nonadherence was observed in half of outpatients with epilepsy. A declining pattern of adherence, observed in a quarter of patients, was associated with more than eight times increased risk of SUDEP. Any ongoing medication interventions must include strategies to maintain and improve ASM adherence if we are to reduce the risk of SUDEP.

Long-term efficacy and safety of cannabidiol in patients with treatment-resistant epilepsies: Four-year results from the expanded access program

OBJECTIVE

Cannabidiol (CBD) expanded access program, initiated in 2014, provided add-on CBD to patients with treatment-resistant epilepsies (TREs) at 35 US epilepsy centers. Prior publications reported results through December 2016; herein, we present efficacy and safety results through January 2019.

METHODS

Patients received plant-derived highly purified CBD (Epidiolex®; 100 mg/ml oral solution), increasing from 2 to 10 mg/kg/day to tolerance or maximum 25-50 mg/kg/day dose, depending on the study site. Efficacy endpoints included percentage change from baseline in median monthly convulsive and total seizure frequency and ≥50%, ≥75%, and 100% responder rates across 12-week visit windows for up to 192 weeks. Adverse events (AEs) were documented at each visit.

RESULTS

Of 892 patients in the safety analysis set, 322 (36%) withdrew; lack of efficacy (19%) and AEs (7%) were the most commonly reported primary reasons for withdrawal. Median (range) age was 11.8 years (range = 0-74.5), and patients were taking a median of three (range = 0-10) antiseizure medications (ASMs) at baseline; the most common ASMs were clobazam (47%), levetiracetam (34%), and valproate (28%). Median top CBD dose was 25 mg/kg/day; median exposure duration was 694 days. Median percentage reduction from baseline ranged 50%-67% for convulsive seizures and 46%-66% for total seizures. Convulsive seizure responder rates (≥50%, ≥75%, and 100% reduction) ranged 51%-59%, 33%-42%, and 11%-17% of patients across visit windows, respectively. AEs were reported in 88% of patients and serious AEs in 41%; 8% withdrew because of an AE. There were 20 deaths during the study deemed unrelated to treatment by the investigator. The most common AEs (≥20% of patients) were diarrhea (33%), seizure (24%), and somnolence (23%).

SIGNIFICANCE

Add-on CBD was associated with sustained seizure reduction up to 192 weeks with an acceptable safety profile and can be used for long-term treatment of TREs.

Mortality, and life expectancy in Epilepsy and Status epilepticus-current trends and future aspects

Patients with epilepsy carry a risk of premature death which is on average two to three times higher than in the general population. The risk of death is not homogenously distributed over all ages, etiologies, and epilepsy syndromes. People with drug resistant seizures carry the highest risk of death compared to those who are seizure free, whose risk is similar as in the general population. Most of the increased risk is directly related to the cause of epilepsy itself. Sudden unexplained death in epilepsy patients (SUDEP) is the most important cause of epilepsy-related deaths especially in the young and middle-aged groups. Population based studies with long-term follow up demonstrated that the first years after diagnosis carry the highest risk of death, while in the later years the mortality decreases. Improved seizure control and being exposed to a specialized comprehensive care centre may help to reduce the risk of death in patients with epilepsy. The mortality of status epilepticus is substantially increased with case fatality rates between 4.6% and 39%, depending on its cause and duration, and the age of the population studied. The epidemiological data on overall and cause specific mortality as well as their determinants and risk factors are critically reviewed and methodological issues pertinent to the studies on mortality of epilepsy and Status epilepticus are discussed.

Sudden unexpected death in epilepsy in children

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related mortality in children and adults living with epilepsy. The incidence of SUDEP is comparable in both children and adults; it is approximately 1.2 per 1000 person years. The pathophysiology of SUDEP is not well understood but may involve mechanisms such as cerebral shutdown, autonomic dysfunction, altered brainstem function, and cardiorespiratory demise. Risk factors for SUDEP include the presence of generalized tonic-clonic seizures, nocturnal seizures, possible genetic predisposition, and non-adherence to antiseizure medications. Pediatric-specific risk factors are not fully elucidated. Despite recommendations from consensus guidelines, many clinicians still do not follow the practice of counseling their patients about SUDEP. SUDEP prevention has been an area of important research focus and includes several strategies, such as obtaining seizure control, optimizing treatment regimens, nocturnal supervision, and seizure detection devices. This review discusses what is currently known about SUDEP risk factors and reviews current and future preventive strategies for SUDEP.

Risk of poststroke epilepsy after reperfusion therapies: A national cohort study

BACKGROUND AND PURPOSE

The risk of poststroke epilepsy (PSE) after endovascular treatment (EVT) is not well characterized. In this nationwide study, we assessed the risk of PSE after EVT and identified associated predictors.

METHODS

We included all individuals (n = 3319) treated with EVT (±intravenous thrombolysis [IVT]) between 2015 and 2019 in the Swedish National Quality Register for EVT. Two control groups were identified from the Swedish Stroke Register: the first treated with IVT alone (n = 3132) and the second with no treatment (n = 3184), both matched for age, sex, stroke severity, and time of stroke.

RESULTS

PSE developed in 7.9% (n = 410). The survival-adjusted 2-year risk was 6.5% (95% confidence interval [CI] = 5.28-7.70) after EVT, 10.0% (95% CI = 8.25-11.75) after IVT, and 12.3% after no revascularization (95% CI = 10.33-14.25). The hazard ratio (HR) of PSE after EVT was almost half compared to no treatment (HR = 0.51, 95% CI = 0.41-0.64). The risk of PSE after EVT was lower compared to no treatment in a multivariable Cox model that adjusted for age, sex, hemicraniectomy, and stroke severity (HR = 0.76, 95% CI = 0.60-0.96). Multivariable predictors of PSE after EVT were large infarction on computed tomography Day 1, high posttreatment National Institutes of Health Stroke Scale score, and need of assistance 3 months after stroke. IVT before EVT was associated with a lower risk of PSE (HR = 0.66, 95% CI = 0.46-0.94).

CONCLUSIONS

This nationwide study identified a reduced risk of PSE after EVT. Markers of severe infarction after EVT were associated with PSE, whereas IVT given before EVT was protective.

Autonomic dysfunction in epilepsy mouse models with implications for SUDEP research

Epilepsy has a high prevalence and can severely impair quality of life and increase the risk of premature death. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in drug-resistant epilepsy and most often results from respiratory and cardiac impairments due to brainstem dysfunction. Epileptic activity can spread widely, influencing neuronal activity in regions outside the epileptic network. The brainstem controls cardiorespiratory activity and arousal and reciprocally connects to cortical, diencephalic, and spinal cord areas. Epileptic activity can propagate trans-synaptically or via spreading depression (SD) to alter brainstem functions and cause cardiorespiratory dysfunction. The mechanisms by which seizures propagate to or otherwise impair brainstem function and trigger the cascading effects that cause SUDEP are poorly understood. We review insights from mouse models combined with new techniques to understand the pathophysiology of epilepsy and SUDEP. These techniques include in vivo, ex vivo, invasive and non-invasive methods in anesthetized and awake mice. Optogenetics combined with electrophysiological and optical manipulation and recording methods offer unique opportunities to study neuronal mechanisms under normal conditions, during and after non-fatal seizures, and in SUDEP. These combined approaches can advance our understanding of brainstem pathophysiology associated with seizures and SUDEP and may suggest strategies to prevent SUDEP.

Cause-specific mortality and life years lost in people with epilepsy: a Danish cohort study

Mortality rates are two to three times higher in people with epilepsy than in the general population. This study aimed to quantify how this increased mortality translates into reduced life expectancy and to identify the underlying causes of deaths, thereby offering suggestions for how to reduce mortality associated with epilepsy. In this population-based cohort study, we included all individuals aged 0-94 years who were living in Denmark between 2000 and 2015. Using the nationwide registers, we identified people diagnosed with epilepsy and estimated the excess of life years lost due to 13 overall and nine specific causes of death. Among 6 022 160 people, we identified 129 598 with epilepsy (52.6% males), with a mean age of epilepsy onset of 36.5 years (standard deviation = 26.3 years). During the 16 years of follow-up, 851 087 individuals died, and of these 36 923 had been diagnosed with epilepsy. The average reduction in life expectancy in people with epilepsy was 11.84 years in males (95% confidence interval: 11.66-12.00) and 10.91 years in females (95% confidence interval: 10.70-11.11) compared to the general population. Life expectancy was reduced irrespective of epilepsy aetiology (symptomatic ∼14 years; idiopathic ∼8-10 years), and in particular in people with epilepsy and psychiatric comorbidity (∼13-16 years). Excess mortality was evident across all causes of death including cardiovascular disorders, accidents, and suicide. People with epilepsy experience a substantial reduction in lifespan that can only partly be explained by underlying conditions. Prevention of epilepsy-related deaths should focus on the consequences of psychiatric comorbidity and on modifiable risk factors associated with preventable causes of death such as accidents and neurological and cardiovascular disorders.

Sudden unexpected death in epilepsy: A bibliometric overview

The mechanism of sudden unexpected death in epilepsy (SUDEP) is elusive and many questions remain unanswered. Autopsy is generally unhelpful in providing evidence for the cause of death, as pathological changes may be on the molecular level. Although histopathological examination occasionally demonstrates pathology such as vascular malformation, old traumatic injury, and tumor, in most cases of SUDEP, the examination is negative. We examined the current status of SUDEP research by performing a bibliometric analysis of studies in the Web of Science Core Collection database published between 2002 and 2022. Our aim was to demonstrate areas of interest and frontiers of SUDEP research. A total of 1803 papers were included in the analysis. The number of published papers focused on SUDEP has been increasing since 2002. Main areas of interest include clinical manifestations, prevalence, treatment, and underlying mechanisms. Research teams from the United States and Europe are leading the way in SUDEP research, while Asia trails behind. Future studies regarding the mechanism and neuropathology of SUDEP are warranted.

Epilepsy and its neurobehavioral comorbidities: Insights gained from animal models

It is well established that epilepsy is associated with numerous neurobehavioral comorbidities, with a bidirectional relationship; people with epilepsy have an increased incidence of depression, anxiety, learning and memory difficulties, and numerous other psychosocial challenges, and the occurrence of epilepsy is higher in individuals with those comorbidities. Although the cause-and-effect relationship is uncertain, a fuller understanding of the mechanisms of comorbidities within the epilepsies could lead to improved therapeutics. Here, we review recent data on epilepsy and its neurobehavioral comorbidities, discussing mainly rodent models, which have been studied most extensively, and emphasize that clinically relevant information can be gained from preclinical models. Furthermore, we explore the numerous potential factors that may confound the interpretation of emerging data from animal models, such as the specific seizure induction method (e.g., chemical, electrical, traumatic, genetic), the role of species and strain, environmental factors (e.g., laboratory environment, handling, epigenetics), and the behavioral assays that are chosen to evaluate the various aspects of neural behavior and cognition. Overall, the interplay between epilepsy and its neurobehavioral comorbidities is undoubtedly multifactorial, involving brain structural changes, network-level differences, molecular signaling abnormalities, and other factors. Animal models are well poised to help dissect the shared pathophysiological mechanisms, neurological sequelae, and biomarkers of epilepsy and its comorbidities.

Stratifying sudden death risk in adults with drug-resistant focal epilepsy: The SUDEP-CARE score

BACKGROUND AND PURPOSE

A clinical risk score for sudden unexpected death in epilepsy (SUDEP) in patients with drug-resistant focal epilepsy could help improve prevention.

METHODS

A case-control study was conducted including (i) definite or probable SUDEP cases collected by the French National Sentinel Mortality Epilepsy Network and (ii) control patients from the French national research database of epilepsy monitoring units. Patients with drug-resistant focal epilepsy were eligible. Multiple logistic regressions were performed. After sensitivity analysis and internal validation, a simplified risk score was developed from the selected variables.

RESULTS

Sixty-two SUDEP cases and 620 controls were included. Of 21 potential predictors explored, seven were ultimately selected, including generalized seizure frequency (>1/month vs. <1/year: adjusted odds ratio [AOR] 2.6, 95% confidence interval [CI] 1.25-5.41), nocturnal or sleep-related seizures (AOR 4.49, 95% CI 2.68-7.53), current or past depression (AOR 2.0, 95% CI 1.19-3.34) or the ability to alert someone of an oncoming seizure (AOR 0.57, 95% CI 0.33-0.98). After internal validation, a clinically usable score ranging from -1 to 8 was developed, with high discrimination capabilities (area under the receiver operating curve 0.85, 95% CI 0.80-0.90). The threshold of 3 has good sensitivity (82.3%, 95% CI 72.7-91.8), whilst keeping a good specificity (82.7%, 95% CI 79.8-85.7).

CONCLUSIONS

These results outline the importance of generalized and nocturnal seizures on the occurrence of SUDEP, and show a protective role in the ability to alert someone of an oncoming seizure. The SUDEP-CARE score is promising and will need external validation. Further work, including paraclinical explorations, could improve this risk score.

Drug-resistant epilepsy and mortality-Why and when do neuromodulation and epilepsy surgery reduce overall mortality

Patients with drug-resistant epilepsy have an increased mortality rate, with the majority of deaths being epilepsy related and 40% due to sudden unexpected death in epilepsy (SUDEP). The impact of epilepsy surgery on mortality has been investigated since the 1970s, with increased interest in this field during the past 15 years. We systematically reviewed studies investigating mortality rate in patients undergoing epilepsy surgery or neuromodulation therapies. The quality of available evidence proved heterogenous and often limited by significant methodological issues. Perioperative mortality following epilepsy surgery was found to be <1%. Meta-analysis of studies that directly compared patients who underwent surgery to those not operated following presurgical evaluation showed that the former have a two-fold lower risk of death and a three-fold lower risk of SUDEP compared to the latter (odds ratio [OR] 0.40, 95% confidence interval [CI]: 0.29-0.56; p < .0001 for overall mortality and OR 0.32, 95% CI: 0.18-0.57; p < .001 for SUDEP). Limited data are available regarding the risk of death and SUDEP in patients undergoing neuromodulation therapies, although some evidence indicates that vagus nerve stimulation might be associated with a lower risk of SUDEP. Several key questions remain to be addressed in future studies, considering the need to better inform patients about the long-term benefit-risk ratio of epilepsy surgery. Dedicated long-term prospective studies will thus be required to provide more personalized information on the impact of surgery and/or neuromodulation on the risk of death and SUDEP.

Sudden Unexpected Death in Epilepsy: Pathogenesis, Risk Factors, and Prevention

Sudden unexpected death in epilepsy (SUDEP) is a tragic and unexpected cause of death in patients with a known diagnosis of epilepsy. It occurs in up to 6.3 to 9.3/1,000 patients with drug-resistant epilepsy. The main three risk factors associated with SUDEP are the presence of generalized tonic-clonic seizures, the presence of a seizure in the past year, and an intellectual disability. There are several mechanisms that can result in SUDEP. The most likely sequence of events appears to be a convulsive seizure, overactivation of the autonomic nervous system, cardiorespiratory dysfunction, and death. While the risk of SUDEP is relatively high in patients with drug-resistant epilepsy, studies indicate that more than 50% of patients and caregivers are unaware of the diagnosis. Counseling about the diagnosis and preventative measures at the time of diagnosis is important. There are numerous interventions that may reduce the risk of SUDEP, including conservative measures such as nocturnal surveillance with a bed partner (where applicable) and automated devices. Optimizing seizure control with antiseizure medications and surgical interventions can result in a reduced risk of SUDEP.

White matter alterations in focal to bilateral tonic-clonic seizures

We examined the white matter of patients with and without focal to bilateral tonic-clonic seizures (FBTCS), and control participants. A neural network based tract segmentation model (Tractseg) was used to isolate tract-specific, track-weighted tensor-based measurements from the tracts of interest. We compared the group differences in the track-weighted tensor-based measurements derived from whole and hemispheric tracts. We identified several regions that displayed significantly altered white matter in patients with focal epilepsy compared to controls. Furthermore, patients without FBTCS showed significantly increased white matter disruption in the inferior fronto-occipital fascicle and the striato-occipital tract. In contrast, the track-weighted tensor-based measurements from the FBTCS cohort exhibited a stronger resemblance to the healthy controls (compared to the non-FBTCS group). Our findings revealed marked alterations in a range of subcortical tracts considered critical in the genesis of seizures in focal epilepsy. Our novel application of tract-specific, track-weighted tensor-based measurements to a new clinical dataset aided the elucidation of specific tracts that may act as a predictive biomarker to distinguish patients likely to develop FBTCS.

Cardiac morbidity and mortality associated with the use of lamotrigine

OBJECTIVE

The US Food and Drug Administration recently issued a warning against the use of the antiseizure medication lamotrigine in people at risk of cardiac rhythm and conduction abnormalities. This study assessed the risk of cardiac morbidity and mortality in new users of lamotrigine.

METHODS

In a Danish population-based cohort study, we followed cohort members aged ≥15 years for the first 2 years after they initiated lamotrigine therapy. The main outcomes were cardiac conduction disorders in people without pre-existing cardiac morbidity and all-cause mortality in people with pre-existing cardiac morbidity. Cox proportional hazards models provided hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for comparison of the risk in current versus past users of lamotrigine.

RESULTS

There were 91 949 (36 618 males [39.8%]) new users of lamotrigine (median age = 45.7 years, interquartile range = 32.0-60.2 years). Among users without pre-existing cardiac disease (n = 86 769), 194 (.23%) developed a cardiac conduction disorder. Comparison of the risk in current and past lamotrigine treatment periods yielded an adjusted HR of new onset cardiac conduction disorder of 1.03 (95% CI = .76-1.40). Among users with pre-existing cardiac disease (n = 5180), 1150 (22.2%) died. Comparison of the risk in current and past lamotrigine treatment periods yielded an adjusted HR for all cause-mortality of 1.05 (95% CI = .93-1.19).

SIGNIFICANCE

In this large population-based study, lamotrigine use was associated neither with a risk of cardiac conduction disorders in people without pre-existing cardiac morbidity nor with all-cause mortality in people with pre-existing cardiac morbidity.

Epilepsy in patients with congenital heart disease: A nationwide cohort study

BACKGROUND

Congenital heart disease (CHD) is the most common congenital defect, and reports suggest an increased risk of subsequent epilepsy. We used Swedish comprehensive population-based registers to investigate the risk of epilepsy in patients with CHD compared to matched controls and identify underlying factors of epilepsy.

METHODS

All patients with CHD born between 1970 and 2017 and 10 age- and sex-matched controls were included. Epilepsy was ascertained by International Statistical Classification of Diseases and Related Health Problems codes, and the cumulative hazard of epilepsy was described using Cox regression.

RESULTS

The study cohort consisted of 71,941 patients with CHD and 714,462 matched controls. The cumulative incidence of epilepsy in the study period was 3% in patients with CHD and 0.9% in controls. The risk of epilepsy was 3.6 times higher (95%, confidence interval: 3.4-3.8) in patients with CHD than in controls. Among patients with CHD, several brain comorbidities, including intellectual disability and stroke, as well as having undergone more than two cardiac interventions were significantly associated with epilepsy in a multivariable model.

CONCLUSIONS

In this nationwide, register-based cohort study, we found an almost fourfold increased risk of epilepsy in patients with CHD compared to controls; however, the absolute risk was low. Among the identified risk factors, stroke may be potentially preventable.

Risk and cause of death in post-traumatic epilepsy: a register-based retrospective cohort study

Objective

Post-traumatic epilepsy (PTE) is common, but its impact on survival after traumatic brain injury (TBI) of different severity and in different demographic patient groups is unknown. We analyzed the risk of death associated with PTE with adjustment for TBI severity, causes of death, and the contribution of epilepsy as direct or contributing cause of death.

Methods

Register-based, retrospective cohort study. All individuals hospitalized in Sweden for a TBI between 2000 and 2010 without prior seizures were identified in the National Patient Register, with follow-up until 2017. Subsequent epilepsy was identified by ICD-10 codes. Time-dependent Cox proportional hazard ratio (HR) was used to assess hazard of death, with epilepsy as a time-updated covariate. Adjusted analyses for age, gender, injury severity and comorbidities were also performed. Causes of death were analyzed using the Cause of Death Register.

Results

Among 111 947 individuals with TBI, subsequent epilepsy diagnosis was associated with a crude HR of 2.3 (95% CI: 2.2–2.4) for death. Stratified analyses showed a HR of 7.8 (95% CI: 6.5–9.4) for death in younger individuals. Epilepsy was a more common underlying cause of death in younger individuals.

Conclusion

PTE is associated with a higher risk of death and epilepsy seems to contribute to a significant proportion of deaths, especially in younger age groups. Future studies on whether improved epilepsy treatment can reduce mortality are needed.

Effect of Fenfluramine on Seizures and Comorbidities in SCN8A-Developmental and Epileptic Encephalopathy: A Case Series

SCN8A-developmental and epileptic encephalopathy is caused by mutations in the SCN8A gene encoding the Na_v 1.6 sodium channel, and is characterized by intractable multivariate seizures and developmental regression. Fenfluramine is a repurposed drug with proven antiseizure efficacy in Dravet syndrome and Lennox-Gastaut syndrome. The effect of fenfluramine treatment was assessed in a retrospective series of three patients with intractable SCN8A epilepsy and severe neurodevelopmental comorbidity (n=2 females; age 2.8-13 years; 8-16 prior failed antiseizure medications (ASM); treatment duration: 0.75-4.2 years). In the 6 months prior to receiving fenfluramine, patients experienced multiple seizure types, including generalized tonic-clonic, focal and myoclonic seizures, and status epilepticus. Overall seizure reduction was 60%-90% in the last 3, 6, and 12 months of fenfluramine treatment. Clinically meaningful improvement was noted in ≥1 non-seizure comorbidity per patient after fenfluramine, as assessed by physician-ratings of ≥"Much Improved" on the Clinical Global Impression of Improvement scale. Improvements included ambulation in a previously non-ambulant patient and better attention, sleep, and language. One patient showed mild irritability which resolved; no other treatment-related adverse events were reported. There were no reports of valvular heart disease or pulmonary arterial hypertension. Fenfluramine may be a promising ASM for randomized clinical trials in SCN8A-related disorders.

CSF biomarkers in patients with epilepsy in Alzheimer’s disease: a nation-wide study

Alzheimer’s disease is the most common neurodegenerative dementia. A subset of Alzheimer’s disease patients develop epilepsy. The risk is higher in young-onset Alzheimer’s disease, but pathophysiological mechanisms remain elusive. The purpose of this study was to assess biomarkers reflecting neurodegeneration in Alzheimer’s disease patients with and without epilepsy. By cross-referencing the largest national laboratory database with Swedish National Patient Register, we could identify CSF biomarker results from 17901 Alzheimer’s disease patients, and compare levels of neurofilament light, glial fibrillary acidic protein, total tau, phosphorylated tau and amyloid beta 42 in patients with (n = 851) and without epilepsy. The concentrations of total tau and phosphorylated tau were higher in Alzheimer’s disease patients with epilepsy than Alzheimer’s disease patients without epilepsy and amyloid beta 42 levels were significantly lower in Alzheimer’s disease patients with epilepsy. No differences in the levels of neurofilament light and glial fibrillary acidic protein were observed. Our study suggests that epilepsy is more common in Alzheimer’s disease patients with more pronounced Alzheimer’s pathology, as determined by the CSF biomarkers. Further studies are needed to investigate the biomarker potential of these CSF markers as predictors of epilepsy course or as indicators of epileptogenesis in Alzheimer’s disease.

How the characteristics of pediatric neurologists in Latin America influence the communication of sudden unexpected death in epilepsy to patients and caregivers

Objective

This study aimed to describe the characteristics of pediatric neurologists (PNs) in Latin America (LA) who attend to children and adolescents with epilepsy and convey to them the risk of sudden unexpected death in epilepsy (SUDEP).

Methods

Personal data and details of discussion of SUDEP with families, including relevance of SUDEP disclosure, frequency of such communication, perceived benefits and risks of disclosure, extent of training received on such disclosure, and professional experience with SUDEP, were collected through an online survey of PNs from LA. Their personal experience in carrying out this conversation was obtained through responses to an open question, further used to identify the main barriers.

Results

Of the 442 surveys received, 367 (83%) were analyzed. Most participants (73.8%) responded that the communication of SUDEP risk was relevant or very relevant; however, only 17.9% reported communicating it always or very frequently. Factors that increased the frequency of SUDEP communication included patients with higher levels of complexity (OR = 2.18, P = .003) and the physician's personal experience with SUDEP (OR = 2.305, P < .001). Direct questions from the family and avoiding scaring them about a rare outcome were the main motivations behind discussing and not discussing SUDEP, respectively. In the open question, respondents identified worries about the patient's ability to understand the information and cultural gaps as barriers. “Informing with the intention of improving adherence to treatment” and “establishing an empathic relationship” were significantly related. Further, the concept of “do not scare” was significantly related to “personal difficulties in discussing SUDEP.”

Significance

Although most PNs agree that communication about SUDEP is relevant, only a minority actually engages in it. Participants identified a lack of appropriate training in such communication as a barrier. A better understanding of communication expectations, education of health professionals, and communication techniques have a strong relevance in diminishing the gap between guidelines and practice.