Sudden unexpected death in epilepsy. A nationwide population‐based study

[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.

Enhancing the action of serotonin by three different mechanisms prevents spontaneous seizure-induced mortality in Dravet mice

OBJECTIVE

Sudden unexpected death in epilepsy (SUDEP) is an underestimated complication of epilepsy. Previous studies have demonstrated that enhancement of serotonergic neurotransmission suppresses seizure-induced sudden death in evoked seizure models. However, it is unclear whether elevated serotonin (5-HT) function will prevent spontaneous seizure-induced mortality (SSIM), which is characteristic of human SUDEP. We examined the effects of 5-HT-enhancing agents that act by three different pharmacological mechanisms on SSIM in Dravet mice, which exhibit a high incidence of SUDEP, modeling human Dravet syndrome.

METHODS

Dravet mice of both sexes were evaluated for spontaneous seizure characterization and changes in SSIM incidence induced by agents that enhance 5-HT-mediated neurotransmission. Fluoxetine (a selective 5-HT reuptake inhibitor), fenfluramine (a 5-HT releaser and agonist), SR 57227 (a specific 5-HT3 receptor agonist), or saline (vehicle) was intraperitoneally administered over an 8-day period in Dravet mice, and the effect of these treatments on SSIM was examined.

RESULTS

Spontaneous seizures in Dravet mice generally progressed from wild running to tonic seizures with or without SSIM. Fluoxetine at 30 mg/kg, but not at 20 or 5 mg/kg, significantly reduced SSIM compared with the vehicle control. Fenfluramine at 1-10 mg/kg, but not .2 mg/kg, fully protected Dravet mice from SSIM, with all mice surviving. Compared with the vehicle control, SR 57227 at 20 mg/kg, but not at 10 or 5 mg/kg, significantly lowered SSIM. The effect of these drugs on SSIM was independent of sex.

SIGNIFICANCE

Our data demonstrate that elevating serotonergic function by fluoxetine, fenfluramine, or SR 57227 significantly reduces or eliminates SSIM in Dravet mice in a sex-independent manner. These findings suggest that deficits in serotonergic neurotransmission likely play an important role in the pathogenesis of SSIM, and fluoxetine and fenfluramine, which are US Food and Drug Administration-approved medications, may potentially prevent SUDEP in at-risk patients.

Premature mortality risk in individuals with convulsive epilepsy: Results from a longitudinal, prospective, population-based study

OBJECTIVE

To assess premature mortality and identify associated risk factors among individuals with convulsive epilepsy in resource-poor settings using a longitudinal, prospective, population-based approach.

METHOD

The study recruited people with convulsive epilepsy who underwent assessment and management of epilepsy at primary healthcare centers in rural Northwest China, including newly diagnosed individuals and previously identified prevalent cases. All participants were confirmed to have epilepsy by neurologists according to strict criteria and were followed up monthly by primary care physicians. Demographic data and cause of death (COD) were obtained from death certificates or verbal autopsies conducted by neurologists, following the International Classification of Diseases, 10th Edition. The standardized mortality ratio (SMR) and proportionate mortality ratio (PMR) for each cause of death were estimated using the Cause-Of-Death Surveillance Dataset of China (2020). Survival analysis was used to identify risk factors associated with all-cause mortality and death directly due to epilepsy.

RESULTS

During 5.9 years of follow-up with 40,947 person-years, there were 781 (11.2%) deaths among 6967 participants. The risk of premature death in people with convulsive epilepsy was 2.7-fold higher than that in the general population. Young participants had a significantly higher risk (standardized mortality ratio 26.5-52.5) of premature death. The proportionate mortality ratio was higher for cerebrovascular disease (15%), sudden unexpected death in epilepsy (SUDEP) (13.4%), cardiovascular disease (11.7%), status epilepsy (SE) (11.3%), and epilepsy-related accidents (14.0%) than other premature mortality cause of deaths. Additionally, the highest standardized proportional mortality ratio (SPMR) was observed from drowning in all cause of death (10.4, 95% confidence interval [CI]: 7.6-13.8), followed by burning (9.0, 95% CI: 3.7-18.9). Factors that increased the risk of all-cause mortality included male sex, late age of onset, short disease duration, high body mass index, monotherapy, and the frequency of generalized tonic-clonic seizures (GTCS). High frequency of generalized tonic-clonic seizures (> 3 attacks in the last year) was an independent risk factor for premature death directly due to epilepsy (including sudden unexpected death in epilepsy, status epilepsy, and epilepsy-related accidents), while early age of onset (≤ 14 years) and long duration of epilepsy (> 20 years) were independent risk factors for sudden unexpected death in epilepsy. In addition, short duration of epilepsy (≤ 20 years) was an independent risk factor for status epilepsy.

CONCLUSIONS

This study demonstrated that individuals with poorly controlled seizures are more likely to experience premature death, with most deaths being epilepsy-related and preventable. These findings underline the importance of effective seizure treatment and the potential impact on reducing premature mortality among people with convulsive epilepsy.

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.

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.

Efficacy and safety of traditional Chinese medicine for the treatment of epilepsy: A updated meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the efficacy and safety of Traditional Chinese Medicine (TCM) in the treatment of epilepsy.

METHODS

A comprehensive search of the database in both Chinese and English was performed. Data from the selected studies were extracted and analyzed independently by two authors.

RESULTS

30 randomized controlled trials (RCTs) were included in the meta-analysis with a total of 2471 patients. Among them, 4 trials (n = 235) focused on TCM monotherapy, while the other 26 trials (n = 2236) assessed the benefit of TCM as an add-on therapy to antiseizure medications (ASMs). For the efficacy, the meta-analysis found (1) The effective rate in TCM monotherapy group was higher than that in control group (OR = 4.92, 95 % CI: 2.29-10.57, Z = 4.08, P 0.0001); (2) The add-on of TCM also increased the effective rate (OR = 3.37, 95 % CI: 2.65-4.30, Z = 9.85, P 0.00001) and seizure freedom rate (OR = 1.93, 95 % CI: 1.53-2.44, Z = 5.58, P 0.00001). In terms of safety, the add-on of TCM reduced the rate of total adverse events (OR = 0.46, 95 % CI: 0.31-0.67, Z = 3.96, P 0.0001) as well as adverse events of the gastrointestinal and nervous system. 26 different TCM prescriptions were used in these included RCTs. Among them, the 5 most frequently used herbs were Acorus tatarinowii (19 out of 26), Glycyrrhiza uralensis (13 out of 26), Gastrodia elata (12 out of 26), Pinellia ternata (11 out of 26) and Poria cocos (11 out of 26).

CONCLUSION

This study suggested that TCM may be a relatively efficacious and safe clinical strategy for the treatment of epilepsy. Several limitations still exist, such as the risk of bias in the included studies, the diversified composition of TCM prescriptions, and the relatively low quality of study design.

Toward automated prediction of sudden unexpected death in epilepsy

Sudden unexpected death in epilepsy (SUDEP) is a devastating yet overlooked complication of epilepsy. The rare and complex nature of SUDEP makes it challenging to study. No prediction or prevention of SUDEP is currently available in a clinical setting. In the past decade, significant advances have been made in our knowledge of the pathophysiologic cascades that lead to SUDEP. In particular, studies of brain, heart, and respiratory functions in both human patients at the epilepsy monitoring unit and animal models during fatal seizures provide critical information to integrate computational tools for SUDEP prediction. The rapid advances in automated seizure detection and prediction algorithms provide a fundamental framework for their adaption in predicting SUDEP. If a SUDEP can be predicted, then there will be a potential for medical intervention to be administered, either by their caregivers or via an implanted device automatically delivering electrical stimulation or medication, and finally save lives from fatal seizures. This article presents recent developments of SUDEP studies focusing on the pathophysiologic basis of SUDEP and computational implications of machine learning techniques that can be adapted and extended for SUDEP prediction. This article also discusses some novel ideas for SUDEP prediction and rescue including principal component analysis and closed-loop intervention.

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.

Sudden unexpected death in epilepsy

PURPOSE OF REVIEW

Sudden unexpected death in epilepsy (SUDEP) is a major contributor to premature mortality in people with epilepsy. This review provides an update on recent findings on the epidemiology of SUDEP, clinical risk factors and potential mechanisms.

RECENT FINDINGS

The overall risk rate of SUDEP is approximately 1 per 1000 patients per year in the general epilepsy population and that children and older adults have a similar incidence. Generalized convulsive seizures (GCS), perhaps through their effects on brainstem cardiopulmonary networks, can cause significant postictal respiratory and autonomic dysfunction though other mechanisms likely exist as well. Work in animal models of SUDEP has identified multiple neurotransmitter systems, which may be future targets for pharmacological intervention. There are also chronic functional and structural changes in autonomic function in patients who subsequently die from SUDEP suggesting that some SUDEP risk is dynamic. Modifiable risks for SUDEP include GCS seizure frequency, medication adherence and nighttime supervision.

SUMMARY

Current knowledge of SUDEP risk factors has identified multiple targets for SUDEP prevention today as we await more specific therapeutic targets that are emerging from translational research studies.

A review of the causes and risk factors for sudden unexpected death in the young

Sudden unexpected death in the young (SUDY) is a tragic event resulting in the fatality of seemingly healthy individuals between the ages of one and 40 years. Whilst studies have been performed on sudden unexpected death in infants, children, and adults respectively, little is known about trends in risk factors and causes of death of SUDY cases. Understanding the factors surrounding these deaths could lead to targeted interventions for at-risk individuals. Hence, a systematic approach to investigate the reported possible causes of SUDY was employed using three major databases and Primo, wherein 67 relevant articles were identified and 2 additional guidelines were read. Sudden unexpected death in epilepsy and sudden cardiac events were well-established causes of death with risk factors such as male predominance, substance use and a familial history identified. It was acknowledged that while the cause of death is established following post-mortem examination in many cases, some remain non-specific or undetermined. Considering the genetic etiology, these cases would be ideal candidates for molecular autopsies in the future. Thus, this review emphasized the significance of acquiring the relevant information to aid in resolving cause of death of these SUDY cases and subsequently highlighted the potential for further studies on risk factors and the value of molecular autopsies.

OUP accepted manuscript

Sudden unexpected death in epilepsy is the most catastrophic outcome of epilepsy. Each year there are as many as 1.65 cases of such death for every 1000 individuals with epilepsy. Currently, there are no methods to predict or prevent this tragic event, due in part to a poor understanding of the pathologic cascade that leads to death following seizures. We recently identified enhanced seizure-induced mortality in four inbred strains from the genetically diverse Collaborative Cross mouse population. These mouse models of sudden unexpected death in epilepsy provide a unique tool to systematically examine the physiological alterations during fatal seizures, which can be studied in a controlled environment and with consideration of genetic complexity. Here, we monitored the brain oscillations and heart functions before, during, and after non-fatal and fatal seizures using a flurothyl-induced seizure model in freely moving mice. Compared with mice that survived seizures, non-survivors exhibited significant suppression of brainstem neural oscillations that coincided with cortical epileptic activities and tachycardia during the ictal phase of a fatal seizure. Non-survivors also exhibited suppressed delta (0.5–4 Hz)/gamma (30–200 Hz) phase-amplitude coupling in cortex but not in brainstem. A connectivity analysis revealed elevated synchronization of cortex and brainstem oscillations in the delta band during fatal seizures compared with non-fatal seizures. The dynamic ictal oscillatory and connectivity features of fatal seizures provide insights into sudden unexpected death in epilepsy and may suggest biomarkers and eventual therapeutic targets.

Sudden unexpected death in epilepsy in persons younger than 50 years: A retrospective nationwide cohort study in Denmark

OBJECTIVE

Persons with epilepsy have an increased mortality including a high risk of sudden unexplained death (SUD), also referred to as sudden unexpected death in epilepsy (SUDEP). We aimed to evaluate the risk of SUDEP in comparison to other causes of death and the risk of SUD in persons with and without epilepsy.

METHODS

We undertook a retrospective population-based cohort study of all Danish citizens with and without epilepsy aged 1-49 years during 2007-2009. All deaths in the population were evaluated, and all cases of SUD identified. Primary causes of death in persons with epilepsy were evaluated independently by three neurologists and one neuropediatrician, using the unified SUDEP criteria.

RESULTS

The three most frequent causes of death in persons with epilepsy were cancer (2.38 per 1000 person-years), SUDEP (1.65 per 1000 person-years), and pneumonia (1.09 per 1000 person-years) compared with cancer (.17 per 1000 person-years), accident-related deaths (.14 per 1000 person-years), and cardiovascular disease (.09 per 1000 person-years) in persons without epilepsy. Considering definite, definite plus, and probable cases, the SUDEP incidence was .27 per 1000 person-years (95% confidence interval [CI] = .11-.64) in children aged 1-17 years and 1.21 per 1000 person-years (95% CI = .96-1.51) in adults aged 18-49 years. Adjusted for age and sex, persons with epilepsy younger than 50 years had a 10.8-fold (95% CI = 9.97-11.64, p < .0001) increased all-cause mortality and a 34.4-fold (95% CI = 23.57-50.28, p < .0001) increased risk of SUD compared with persons without epilepsy. SUDEP accounted for 23.3% of all SUD.

SIGNIFICANCE

This nationwide study of all deaths in persons with epilepsy younger than 50 years found a lower SUDEP risk in children compared with adults, and that epilepsy was a major risk factor for SUD in the background population. This underlines the importance of addressing risk factors for SUDEP to prevent premature death.

Definite SUDEP population in Bexar County, Texas: A 36-year data registry

OBJECTIVE

Sudden unexplained death in epilepsy (SUDEP) is one of the leading causes of mortality in epilepsy. In this study, cases of definite SUDEP are reported for Bexar County from a 36-year period.

METHODS

Death reports by Bexar County Medical Examiner (BCME) from 1983 to 2018 were reviewed to identify cases with definite SUDEP. The findings were based upon investigators' reports, which included medical history, medication list, sleep position, time of death, and pathology reports. In addition to these potential risk factors, body mass indices (BMI), as well as heart, lung, and brain weights were compared between SUDEP victims with therapeutic vs subtherapeutic anti-seizure medication (ASM) levels.

RESULTS

Definite SUDEP was identified in 286 cases. The incidence of definite SUDEP was 0.51 ± 0.26/1000 person-years among PWE and 0.56 ± 0.29 per 100,000 person-years among the general population in Bexar County. The median age was 37 years old (interquartile range 27-48), and the majority were male (65%). While 171 (60%) people were prescribed at least one ASM, ASM levels were subtherapeutic in 239 cases (83.6%). Risk factors for SUDEP did not differ between SUDEP victims with therapeutic vs subtherapeutic ASM levels. While BMIs were only slightly increased in adherent vs nonadherent SUDEP victims, they were significantly associated with subtherapeutic ASM levels. Abnormal lung, heart, and brain weights were reported in 48 (16.8%), 67 (23.4%), and 43 (15.0%) SUDEP cases, respectively.

SIGNIFICANCE

This study is one of the largest autopsy-based registries of definite SUDEP. Subtherapeutic ASM levels measured in post-mortem blood samples suggest that nonadherence to ASM therapy was a leading risk factor for SUDEP. As BMI was elevated in this cohort, and obesity was significantly associated with subtherapeutic ASM levels, it may also be a risk factor for SUDEP. Case-controlled studies are needed to validate the specific role of obesity and related comorbidities in this population.

Severity of Peri-ictal Respiratory Dysfunction With Epilepsy Duration and Patient Age at Epilepsy Onset

Respiratory dysfunction preceding death is fundamental in sudden unexpected death in epilepsy (SUDEP) pathophysiology. Hypoxia occurs with one-third of seizures. In temporal lobe epilepsy, there is volume loss in brainstem regions involved in autonomic control and increasing neuropathological changes with duration of epilepsy suggesting increasingly impaired regulation of ventilation. In animal models, recurrent hypoxic episodes induce long-term facilitation (LTF) of ventilatory function, however, LTF is less robust in older animals. LTF of ventilation may, to some degree, ameliorate the deleterious effects of progressive brainstem atrophy. We investigated the possibility that the duration of epilepsy, or age at epilepsy onset, may impact the severity of seizure-associated respiratory dysfunction. Patients with focal epilepsy undergoing video-EEG telemetry in the epilepsy monitoring unit (EMU) were studied. We found a significant relationship between age at epilepsy onset and duration of peri-ictal oxygen desaturation for focal seizures not progressing to bilateral tonic-clonic seizures, with longer duration of peri-ictal oxygen desaturation in patients with epilepsy onset at an older age but no significant relationships between duration of epilepsy or age at EMU admission and ventilatory dysfunction. Our findings suggest an intriguing possibility that LTF of ventilation may be protective when epilepsy starts at a younger age.

SUDEP cases require thorough post-mortem work-up to eventually detect an underlying cause

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Takotsubo broke-heart syndrome and neurogenic pulmonary edema should be considered as causes of SUDEP.

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Each SUDEP case should undergo a thorough post-mortem work-up to eventually elucidate the cause of SUDEP.

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Patients at risk of SUDEP should be carefully guided and monitored intra-vitam.

Nocturnal events in children: When and how to evaluate

Nocturnal events of wide variety and concern are frequently reported by patients and their caregivers. To evaluate suspected abnormal events, primary care physicians must first be familiar with normal behaviors, movements and breathing patterns. Abnormal nocturnal events can then be categorized as nocturnal seizure, parasomnia, sleep-related movement disorder or sleep-related breathing disorder. Diagnoses in the above categories can be made clinically; however, it is important to know when to refer for additional evaluation. Comprehensive literature review was undertaken of nocturnal and sleep-related disorders. This guide reviews nocturnal seizures, normal and abnormal nonepileptic movements and behaviors, discusses broad indications for referral for electroencephalography (EEG) or polysomnography (PSG), and guides counseling and management for patients and their families, ultimately aiding in interpretation of both findings and prognosis. Epilepsy syndromes can result in seizures during sleep or adjacent periods of wakefulness. Parasomnias and sleep-related movement disorders tend to also occur in childhood and may be distinguished clinically. Referral to additional specialists for specific studies including EEG or PSG can be necessary, while other times a knowledgeable and vigilant clinician can contribute to a prompt diagnosis based on clinical features. Nocturnal events often can be managed with parental reassurance and watchful waiting, but treatment or evaluation may be needed. Sleep-related breathing disorders are important to recognize as they present very differently in children than in adults and early intervention can be life-saving. This review should allow both primary and subspecialty non-neurologic pediatric and adolescent health care providers to better utilize EEG and PSG as part of a larger comprehensive clinical approach, distinguishing and managing both epileptic and nonepileptic nocturnal disorders of concern while fostering communication across providers to facilitate and coordinate better holistic long-term care of pediatric and adolescent patients.

SUDEP classification: Discordances between forensic investigators and epileptologists

We compared sudden unexpected death in epilepsy (SUDEP) diagnosis rates between North American SUDEP Registry (NASR) epileptologists and original death investigators, to determine degree and causes of discordance. In 220 SUDEP cases with post-mortem examination, we recorded the epileptologist adjudications and medical examiner- and coroner- (ME/C) listed causes of death (CODs). COD diagnosis concordance decreased with NASR's uncertainty in the SUDEP diagnosis: highest for Definite SUDEP (84%, n = 158), lower in Definite Plus (50%, n = 36), and lowest in Possible (0%, n = 18). Rates of psychiatric comorbidity, substance abuse, and toxicology findings for drugs of abuse were all higher in discordant cases than concordant cases. Possible SUDEP cases, an understudied group, were significantly older, and had higher rates of cardiac, drug, or toxicology findings than more certain SUDEP cases. With a potentially contributing or competing COD, ME/Cs favored non-epilepsy-related diagnoses, suggesting a bias toward listing CODs with structural or toxicological findings; SUDEP has no pathognomonic features. A history of epilepsy should always be listed on death certificates and autopsy reports. Even without an alternate COD, ME/Cs infrequently classified COD as "SUDEP." Improved collaboration and communication between epilepsy and ME/C communities improve diagnostic accuracy, as well as bereavement and research opportunities.

Association between epilepsy and challenging behaviour in adults with intellectual disabilities: systematic review and meta-analysis

BACKGROUND

Previous systematic reviews showed no significant association between epilepsy and challenging behaviours in adults with intellectual disabilities.

AIMS

To identify whether there is an association between epilepsy and challenging behaviour in adults with intellectual disabilities by carrying out a systematic review of published data. PROSPERO registration number: CRD42020178092.

METHOD

We searched five databases and hand-searched six journals. Two authors independently screened titles, abstracts and full articles using a standardised eligibility checklist. Several meta-analyses were carried out.

RESULTS

The narrative analysis of data from 34 included articles (14 168 adults with intellectual disabilities, 4781 of whom also had epilepsy) showed no significant association between epilepsy and challenging behaviour. Meta-analysis was possible on data from 16 controlled studies. This showed no significant intergroup difference but after sensitivity analysis meta-analysis of 10 studies showed a significantly higher rate of overall challenging behaviour in the epilepsy group (effect size: 0.16) compared with the non-epilepsy group. Aggression and self-injurious behaviour both showed a statistically significant higher rate in the epilepsy group, with very small effect sizes (0.16 and 0.28 respectively). No significant intergroup difference was observed in the rate of stereotypy.

CONCLUSIONS

The findings are contradictory and must be interpreted with caution because of the difficulty in pooling data from varied studies, which is likely to introduce confounding. Where significant differences were found, effect sizes are small and may not be clinically significant, and there are major methodological flaws in the included studies, which should be addressed in future large-scale properly controlled studies.

Seizure-related apneas have an inconsistent linkage to amygdala seizure spread

OBJECTIVE

Sudden unexpected death in epilepsy (SUDEP) is a frequent cause of death in epilepsy. Respiratory dysfunction is implicated as a critical factor in SUDEP pathophysiology. Human studies have shown that electrical stimulation of the amygdala resulted in apnea, indicating that the amygdala has a role in respiration control. Unilateral amygdala stimulation resulted in immediate onset of respiratory dysfunction occurring only during nose breathing. In small numbers of patients, some but not all spontaneous seizures resulted in apnea occurring shortly after seizure spread to the amygdala. With this study we aimed to determine whether seizure onset or spread to the amygdala was necessary and sufficient to cause apnea.

METHODS

We investigated the temporal relationship between apnea/hypopnea (AH) onset and initial seizure involvement within the amygdala in patients with implanted depth electrodes.

RESULTS

Data from 17 patients (11 female) with 47 seizures were analyzed. With seven seizures (three patients), AH preceded amygdala seizure involvement by 2 to 55 seconds. There was no AH with four seizures (three patients) that involved the amygdala. With eight seizures (four patients) AH occurred within 2 seconds following amygdala seizure onset. With 28 seizures, AH started >2 seconds after amygdala seizure onset (range 3-158 seconds). Following seizure onset, there was a significant difference between AH onset time and amygdala seizure onset (P < .001). The mean ± standard deviation (SD) AH onset was 27.8 ± 41.06 seconds, and the mean time to amygdala involvement was 8.83 ± 20.19 seconds.

SIGNIFICANCE

There is a wide range of AH onset times relative to amygdala seizure involvement. With some seizures, amygdala seizure involvement occurs without AH. With other seizures, AH precedes amygdala seizures, suggesting that, with spontaneous seizures, involvement of the amygdala may not be crucial to induction of AH with all seizures. Other pathophysiology impacting brainstem respiratory networks may be of greater relevance to seizure-triggered apneas.

Autonomic dysregulation in children with epilepsy with postictal generalized EEG suppression following generalized convulsive seizures

OBJECTIVE

Postictal generalized electroencephalographic suppression (PGES) has been associated with sudden unexpected death in epilepsy (SUDEP) in adults. Decreased heart rate variability (HRV) is one clinical marker of SUDEP in adults with epilepsy. The objective of this study was to analyze the characteristics of HRV associated with generalized convulsive seizures (GCS) ± PGES in children.

METHODS

Nine hundred and seventy-seven consecutive children who underwent prolonged scalp video-EEG (vEEG) and 1-lead electrocardiogram (ECG) monitoring at the Hospital for Sick Children, Toronto, Ontario, Canada were reviewed retrospectively from 2009 to 2011. Thirty-five children had GCS captured during their vEEG with or without PGES and met inclusion criteria. Children were subdivided into three age groups and compared with age-matched controls: 3-6 years; 7-12 years; and 13-18 years. Interictal HRV was measured at 5 min during N2 sleep. Preictal HRV was measured at 1 h prior to GCS onset, and postictal HRV was measured at 3 min post-GCS cessation. Low frequency (LF: ms², 0.04-0.15 Hz) and high frequency (HF: ms², 0.15-0.4 Hz) bands of heart rate oscillations were analyzed during the interictal and preictal periods. The root mean square of successive differences (RMSSDs) was analyzed during the following time points: interictal; preictal; and postictal.

RESULTS

Thirty-five children had GCS: 18 children with PGES [3-6 years (n = 2); 7-12 years (n = 6); 13-18 years (n = 10)] and 17 children without PGES [3-6 years (n = 6); 7-12 years (n = 5); 13-18 years (n = 6)]. Seventeen additional age-matched controls were identified [3-6 years (n = 3); 7-12 years (n = 5); 13-18 years (n = 9)]. Seventy-four GCS were captured consisting of 36 GCS + PGES and 38 GCS - PGES. There was no difference of interictal HRV among children with GCS ± PGES and controls. The preictal LF and HF in 36 GCS + PGES were significantly higher compared with 38 GCS - PGES (p < 0.01). The postictal RMSSD in 36 GCS + PGES was significantly higher compared with 38 GCS - PGES (p < 0.01). The pre- to postictal RMSSD change was significantly lower in children with GCS + PGES than in those with GCS - PGES (p = 0.035).

CONCLUSIONS

In summary, the preictal HRV in GCS + PGES was significantly higher than in children with GCS - PGES. The higher remaining postictal RMSSD in children with GCS + PGES is a potential indicator of autonomic dysregulation. In certain children with epilepsy, autonomic dysregulation may contribute to poor recovery from a GCS with subsequent PGES, thereby contributing to SUDEP. Heart rate variability and autonomic regulation in children with epilepsy should be further studied prospectively in order to better understand the mechanism by which PGES may lead to SUDEP.