Altered ventilatory responses to hypercapnia-hypoxia challenges in a preclinical SUDEP model involve orexin neurons.

Failure to recover from repeated hypercapnia and hypoxemia (HH) challenges caused by severe GCS and postictal apneas may contribute to sudden unexpected death in epilepsy (SUDEP). Our previous studies found orexinergic dysfunction contributes to respiratory abnormalities in a preclinical model of SUDEP, Kcna1-/- mice. Here, we developed two gas challenges consisting of repeated HH exposures and used whole body plethysmography to determine whether Kcna1-/- mice have detrimental ventilatory responses. Kcna1-/- mice exhibited an elevated ventilatory response to a mild repeated hypercapnia-hypoxia (HH) challenge compared to WT. Moreover, 71% of Kcna1-/- mice failed to survive a severe repeated HH challenge, whereas all WT mice recovered. We next determined whether orexin was involved in these differences. Pretreating Kcna1-/- mice with a dual orexin receptor antagonist rescued the ventilatory response during the mild challenge and all subjects survived the severe challenge. In ex vivo extracellular recordings in the lateral hypothalamus of coronal brain slices, we found reducing pH either inhibits or stimulates putative orexin neurons similar to other chemosensitive neurons; however, a significantly greater percentage of putative orexin neurons from Kcna1-/-mice were stimulated and the magnitude of stimulation was increased resulting in augmentation of the calculated chemosensitivity index relative to WT. Collectively, our data suggest that increased chemosensitive activity of orexin neurons may be pathologic in the Kcna1-/- mouse model of SUDEP, and contribute to elevated ventilatory responses. Our preclinical data suggest that those at high risk for SUDEP may be more sensitive to HH challenges, whether induced by seizures or other means; and the depth and length of the HH exposure could dictate the probability of survival.

Decreased ability to manage increases in reactive oxygen species may underlie susceptibility to arrhythmias in mice lacking Scn1b.

Scn1b plays essential roles in the heart, where it encodes ß1 subunits that serve as modifiers of gene expression, cell surface channel activity, and cardiac conductivity. Reduced ß1 function is linked to electrical instability in various diseases with cardiac manifestations and increased susceptibility to arrhythmias. Recently, we demonstrated that loss of Scn1b in mice leads to compromised mitochondria energetics and reactive oxygen species (ROS) production. In this study, we examined the link between increased ROS and arrhythmia susceptibility in Scn1b-/- mice. In addition, ROS scavenging capacity can be overwhelmed during prolonged oxidative stress, increasing arrhythmia susceptibility. Therefore, we isolated whole hearts and cardiomyocytes from Scn1b-/- and Scn1b+/+ mice and subjected them to an oxidative challenge with diamide, a glutathione oxidant. Next, we analyzed gene expression and activity of antioxidant enzymes in Scn1b-/- hearts. Cells isolated from Scn1b-/- hearts died faster and displayed higher rates of ROS accumulation preceding cell death compared to those from Scn1b+/+. Furthermore, Scn1b-/- hearts showed higher arrhythmia scores and spent less time free of arrhythmia. Lastly, we found that protein expression and enzymatic activity of glutathione peroxidase is increased in Scn1b-/- hearts compared to wild-type. Our results indicate that Scn1b-/- mice have decreased capability to manage ROS during prolonged oxidative stress. ROS accumulation is elevated and appears to overwhelm ROS scavenging through the glutathione system. This imbalance creates the potential for altered cell energetics that may underlie increased susceptibility to arrhythmias or other adverse cardiac outcomes.

Allelic heterogeneity in a patient with postzygotic MTOR-related hypomelanosis of Ito with neurodevelopmental abnormalities.

A case of mosaic MTOR-associated hemimegalencephaly and hypomelanosis of Ito, died at 33 probably because of sudden unexpected death in epilepsy. Assessment of the variant allele fraction (VAF) in different tissues postmortem showed high variability not correlated with clinical features, representing the most detailed assessment of VAFs in different tissues to date.

Known pathogenic gene variants and new candidates detected in sudden unexpected infant death using whole genome sequencing.

The purpose of this study is to gain insights into potential genetic factors contributing to the infant's vulnerability to Sudden Unexpected Infant Death (SUID). Whole Genome Sequencing (WGS) was performed on 144 infants that succumbed to SUID, and 573 healthy adults. Variants were filtered by gnomAD allele frequencies and predictions of functional consequences. Variants of interest were identified in 88 genes, in 64.6% of our cohort. Seventy-three of these have been previously associated with SIDS/SUID/SUDP. Forty-three can be characterized as cardiac genes and are related to cardiomyopathies, arrhythmias, and other conditions. Variants in 22 genes were associated with neurologic functions. Variants were also found in 13 genes reported to be pathogenic for various systemic disorders and in two genes associated with immunological function. Variants in eight genes are implicated in the response to hypoxia and the regulation of reactive oxygen species (ROS) and have not been previously described in SIDS/SUID/SUDP. Seventy-two infants met the triple risk hypothesis criteria. Our study confirms and further expands the list of genetic variants associated with SUID. The abundance of genes associated with heart disease and the discovery of variants associated with the redox metabolism have important mechanistic implications for the pathophysiology of SUID.

Quantitative cellular pathology of the amygdala in temporal lobe epilepsy and correlation with magnetic resonance imaging volumetry, tissue microstructure, and sudden unexpected death in epilepsy risk factors.

OBJECTIVE: Amygdala enlargement can occur in temporal lobe epilepsy, and increased amygdala volume is also reported in sudden unexpected death in epilepsy (SUDEP). Apnea can be induced by amygdala stimulation, and postconvulsive central apnea (PCCA) and generalized seizures are both known SUDEP risk factors. Neurite orientation dispersion and density imaging (NODDI) has recently provided additional information on altered amygdala microstructure in SUDEP. In a series of 24 surgical temporal lobe epilepsy cases, our aim was to quantify amygdala cellular pathology parameters that could predict enlargement, NODDI changes, and ictal respiratory dysfunction. METHODS: Using whole slide scanning automated quantitative image analysis methods, parallel evaluation of myelin, axons, dendrites, oligodendroglia, microglia, astroglia, neurons, serotonergic networks, mTOR-pathway activation (pS6) and phosphorylated tau (pTau; AT8, AT100, PHF) in amygdala, periamygdala cortex, and white matter regions of interest were compared with preoperative magnetic resonance imaging data on amygdala size, and in 13 cases with NODDI and evidence of ictal-associated apnea. RESULTS: We observed significantly higher glial labeling (Iba1, glial fibrillary acidic protein, Olig2) in amygdala regions compared to cortex and a strong positive correlation between Olig2 and Iba1 in the amygdala. Larger amygdala volumes correlated with lower microtubule-associated protein (MAP2), whereas higher NODDI orientation dispersion index correlated with lower Olig2 cell densities. In the three cases with recorded PCCA, higher MAP2 and pS6-235 expression was noted than in those without. pTau did not correlate with SUDEP risk factors, including seizure frequency. SIGNIFICANCE: Histological quantitation of amygdala microstructure can shed light on enlargement and diffusion imaging alterations in epilepsy to explore possible mechanisms of amygdala dysfunction, including mTOR pathway activation, that in turn may increase the risk for SUDEP.

Disruption of adenosine metabolism increases risk of seizure-induced death despite decreased seizure severity.

OBJECTIVE: Respiratory arrest plays an important role in sudden unexpected death in epilepsy (SUDEP). Adenosine is of interest in SUDEP pathophysiology due to its influence on seizures and breathing. The objective of this investigation was to examine the role of adenosine in seizure severity, seizure-induced respiratory disruption, and seizure-induced death using mouse models. Understanding adenosinergic contributions to seizure cessation and seizure-induced death may provide insights into how SUDEP can be prevented while avoiding increased seizure severity. METHODS: Our approach was to examine: (1) seizure severity and seizure-induced death after 15 mA electroshock seizures and during repeated pentylenetetrazol (PTZ) administration in wild-type mice (Adk+/+) and transgenic mice with reduced adenosine metabolism (Adk+/-); (2) the postictal hypercapnic ventilatory response (HCVR) in wild-type mice (the postictal HCVR could not be examined in Adk+/- mice due to their high mortality rate); and (3) the effects of adenosinergic drugs on seizure severity and seizure-induced death following maximal electroshock (MES). RESULTS: Adk+/- mice were more vulnerable to seizure-induced death in the 15 mA electroshock and repeated PTZ models. Despite increased mortality, Adk+/- mice had comparable seizure severity in the PTZ model and reduced seizure severity in the 15 mA electroshock model. Breathing and HCVR were suppressed by 15 mA electroshock seizures in wild-type mice. Pharmacological inhibition of adenosine metabolism decreased MES seizure severity but did not increase mortality. A1 selective and nonselective adenosine receptor antagonists increased seizure-induced death following MES. SIGNIFICANCE: Adenosine has opposing effects on seizure severity and seizure-induced death. On the one hand, our seizure severity data highlight the importance of adenosine in seizure suppression. On the other hand, our mortality data indicate that excessive extracellular adenosine signaling can increase the risk of seizure-induced respiratory arrest.

Serotonin 2C receptor in a rat model of temporal lobe epilepsy: From brainstem expression to pharmacological blockade in relation to ventilatory function.

Because of its involvement in breathing control and neuronal excitability, dysregulation of the serotonin (5-HT) 2C receptor (5-HT2C) might play a key role in sudden unexpected death in epilepsy. Seizure-induced respiratory arrest is thus prevented by a 5-HT2B/C agonist in different seizure model. However, the specific contribution of 5-HT2C in chronic epilepsy-related respiratory dysfunction remains unknown. In a rat model of temporal lobe epilepsy (EPI rats), in which we previously reported interictal respiratory dysfunctions and a reduction of brainstem 5-HT tone, quantitative reverse transcriptase polymerase chain reaction showed overexpression of TPH2 (5-HT synthesis enzyme), SERT (5-HT reuptake transporter), and 5-HT2C transcript levels in the brainstem of EPI rats, and of RNA-specific adenosine deaminase (ADAR1, ADAR2) involved in the production of 5-HT2C isoforms. Interictal ventilation was assessed with whole-body plethysmography before and 2 h after administration of SB242084 (2 mg/kg), a specific antagonist of 5-HT2C. As expected, SB242084 administration induced a progressive decrease in ventilatory parameters and an alteration of breathing stability in both control and EPI rats. However, the size of the SB242084 effect was lower in EPI rats than in controls. Increased 5-HT2C gene expression in the brainstem of EPI rats could be part of a compensatory mechanism against epilepsy-related low 5-HT tone and expression of 5-HT2C isoforms for which 5-HT affinity might be lower.

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.

Effect of adenosinergic manipulations on amygdala-kindled seizures in mice: Implications for sudden unexpected death in epilepsy.

OBJECTIVE: Sudden unexpected death in epilepsy (SUDEP) results in more years of potential life lost than any neurological condition with the exception of stroke. It is generally agreed that SUDEP happens due to some form of respiratory, cardiac, and electrocerebral dysfunction following a seizure; however, the mechanistic cause of these perturbations is unclear. One possible explanation lies with adenosinergic signaling. Extracellular levels of the inhibitory neuromodulator adenosine rapidly rise during seizures, a countermeasure that is necessary for seizure termination. Previous evidence has suggested that excessive adenosinergic inhibition could increase the risk of SUDEP by silencing brain areas necessary for life, such as the respiratory nuclei of the brainstem. The goal of this investigation was to further clarify the role of adenosine in seizure-induced respiratory and electrocerebral dysfunction. METHODS: To determine the role of adenosine in postictal physiological dysregulation, we pharmacologically manipulated adenosine signaling prior to amygdala-kindled seizures in mice while recording electroencephalogram (EEG), electromyogram, and breathing using whole body plethysmography. The adenosinergic drugs used in this study included selective and nonselective adenosine receptor antagonists and inhibitors of adenosine metabolism. RESULTS: We found that high doses of adenosine receptor antagonists caused some seizures to result in seizure-induced death; however, counterintuitively, animals in these conditions that did not experience seizure-induced death had little or no postictal generalized EEG suppression. Inhibitors of adenosine metabolism had no effect on postictal breathing but did worsen some postictal electrocerebral outcomes. SIGNIFICANCE: The unexpected effect of high doses of adenosine antagonists on seizure-induced death observed in this study may be due to the increase in seizure severity, vasoconstriction, or phosphodiesterase inhibition caused by these drugs at high doses. These findings further clarify the role of adenosine in seizure-induced death and may have implications for the consumption of caffeine in epilepsy patients and the prevention of SUDEP.

A systematic literature review on the global epidemiology of Dravet syndrome and Lennox-Gastaut syndrome: Prevalence, incidence, diagnosis, and mortality.

Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS) are rare developmental and epileptic encephalopathies associated with seizure and nonseizure symptoms. A comprehensive understanding of how many individuals are affected globally, the diagnostic journey they face, and the extent of mortality associated with these conditions is lacking. Here, we summarize and evaluate published data on the epidemiology of DS and LGS in terms of prevalence, incidence, diagnosis, genetic mutations, and mortality and sudden unexpected death in epilepsy (SUDEP) rates. The full study protocol is registered on PROSPERO (CRD42022316930). After screening 2172 deduplicated records, 91 unique records were included; 67 provided data on DS only, 17 provided data on LGS only, and seven provided data on both. Case definitions varied considerably across studies, particularly for LGS. Incidence and prevalence estimates per 100 000 individuals were generally higher for LGS than for DS (LGS: incidence proportion = 14.5-28, prevalence = 5.8-60.8; DS: incidence proportion = 2.2-6.5, prevalence = 1.2-6.5). Diagnostic delay was frequently reported for LGS, with a wider age range at diagnosis reported than for DS (DS, 1.6-9.2 years; LGS, 2-15 years). Genetic screening data were reported by 63 studies; all screened for SCN1A variants, and only one study specifically focused on individuals with LGS. Individuals with DS had a higher mortality estimate per 1000 person-years than individuals with LGS (DS, 15.84; LGS, 6.12) and a lower median age at death. SUDEP was the most frequently reported cause of death for individuals with DS. Only four studies reported mortality information for LGS, none of which included SUDEP. This systematic review highlights the paucity of epidemiological data available for DS and especially LGS, demonstrating the need for further research and adoption of standardized diagnostic criteria.

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.

Minimum clinical utility standards for wearable seizure detectors: A simulation study.

OBJECTIVE: Epilepsy management employs self-reported seizure diaries, despite evidence of seizure underreporting. Wearable and implantable seizure detection devices are now becoming more widely available. There are no clear guidelines about what levels of accuracy are sufficient. This study aimed to simulate clinical use cases and identify the necessary level of accuracy for each. METHODS: Using a realistic seizure simulator (CHOCOLATES), a ground truth was produced, which was then sampled to generate signals from simulated seizure detectors of various capabilities. Five use cases were evaluated: (1) randomized clinical trials (RCTs), (2) medication adjustment in clinic, (3) injury prevention, (4) sudden unexpected death in epilepsy (SUDEP) prevention, and (5) treatment of seizure clusters. We considered sensitivity (0%-100%), false alarm rate (FAR; 0-2/day), and device type (external wearable vs. implant) in each scenario. RESULTS: The RCT case was efficient for a wide range of wearable parameters, though implantable devices were preferred. Lower accuracy wearables resulted in subtle changes in the distribution of patients enrolled in RCTs, and therefore higher sensitivity and lower FAR values were preferred. In the clinic case, a wide range of sensitivity, FAR, and device type yielded similar results. For injury prevention, SUDEP prevention, and seizure cluster treatment, each scenario required high sensitivity and yet was minimally influenced by FAR. SIGNIFICANCE: The choice of use case is paramount in determining acceptable accuracy levels for a wearable seizure detection device. We offer simulation results for determining and verifying utility for specific use case and specific wearable parameters.

Neurocardiac pathologies associated with potassium channelopathies.

Voltage-gated potassium channels are expressed throughout the human body and are essential for physiological functions. These include delayed rectifiers, A-type channels, outward rectifiers, and inward rectifiers. They impact electrical function in the heart (repolarization) and brain (repolarization and stabilization of the resting membrane potential). KCNQx and KCNHx encode Kv7.x and Kv11.x proteins, which form delayed rectifier potassium channels. KCNQx and KCNHx channelopathies are associated with both cardiac and neuronal pathologies. These include electrocardiographic abnormalities, cardiac arrhythmias, sudden cardiac death (SCD), epileptiform discharges, seizures, bipolar disorder, and sudden unexpected death in epilepsy (SUDEP). Due to the ubiquitous expression of KCNQx and KCNHx channels, abnormalities in their function can be particularly harmful, increasing the risk of sudden death. For example, KCNH2 variants have a dual role in both cardiac and neuronal pathologies, whereas KCNQ2 and KCNQ3 variants are associated with severe and refractory epilepsy. Recurrent and uncontrolled seizures lead to secondary abnormalities, which include autonomics, cardiac electrical function, respiratory drive, and neuronal electrical activity. Even with a wide array of anti-seizure therapies available on the market, one-third of the more than 70 million people worldwide with epilepsy have uncontrolled seizures (i.e., intractable/drug-resistant epilepsy), which negatively impact neurodevelopment and quality of life. To capture the current state of the field, this review examines KCNQx and KCNHx expression patterns and electrical function in the brain and heart. In addition, it discusses several KCNQx and KCNHx variants that have been clinically and electrophysiologically characterized. Because these channel variants are associated with multi-system pathologies, such as epileptogenesis, Kv7 channel modulators provide a potential anti-seizure therapy, particularly for people with intractable epilepsy. Ultimately an increased understanding of the role of Kv channels throughout the body will fuel the development of innovative, safe, and effective therapies for people at a high risk of sudden death (SCD and SUDEP).

Identifying co-morbidities and risk in people with epilepsy: The Maltese experience.

BACKGROUND: People with epilepsy are at increased risk of multiple co-morbidities that may influence risk of adverse outcomes including impact on quality of life and premature mortality. These risk factors include potentially modifiable clinical characteristics associated with sudden unexpected death in epilepsy (SUDEP). For services to tackle risk, the clinical complexity of the target epilepsy population needs to be defined. While this has been comprehensively studied in large, economically developed countries little knowledge of these issues exist in small economically developed countries, like Malta (population: 500,000). METHODS: This was a single centre study focused exclusively on patients attending Gozo General Hospital (GGH) Malta. STROBE guidance for reporting cross sectional studies was used to design and report the study. This was a retrospective review of standard care and SUDEP and seizure risks provided to all adults (over 18 years) with epilepsy attending GGH (2018-2021). RESULTS: The review identified 68 people and 92% were compliant with their anti-seizure medication. A fifth (21%) had an intellectual disability. Despite only one patient having a psychotic illness, 19% were on antipsychotic medication. Only 18% of patients had a specific epilepsy care plan, 6% nocturnal surveillance and none had received advice on SUDEP. DISCUSSION: Patient outcomes may be improved with increasing rates of personalized epilepsy care plans, appropriate nocturnal surveillance and reducing the prescription of antipsychotic medication as it is associated with greater risk of mortality. Issues such as stigma and shame appear to play a significant role in small communities and their access to care.

Ironing out the Links: Ferroptosis in epilepsy and SUDEP.

Iron is a crucial element for almost all organisms because it plays a vital role in oxygen transport, enzymatic processes, and energy generation due to its electron transfer capabilities. However, its dysregulation can lead to a form of programmed cell death known as ferroptosis, which is characterized by cellular iron accumulation, reactive oxygen species (ROS) production, and unrestricted lipid peroxidation. Both iron and ferroptosis have been identified as key players in the pathogenesis of various neurodegenerative diseases. While in epilepsy this phenomenon remains relatively understudied, seizures can be considered hypoxic-ischemic episodes resulting in increased ROS production, lipid peroxidation, membrane disorganization, and cell death. All of this is accompanied by elevated intracellular free Fe2+ concentration and hemosiderin precipitation, as existing reports suggest a significant accumulation of iron in the brain and heart associated with epilepsy. Generalized tonic-clonic seizures (GTCS), a primary risk factor for Sudden Unexpected Death in Epilepsy (SUDEP), not only have an impact on the brain but also lead to cardiogenic dysfunctions associated with "Iron Overload and Cardiomyopathy" (IOC) and "Epileptic heart" characterized by electrical and mechanical dysfunction and a high risk of malignant bradycardia. In line with this phenomenon, studies conducted by our research group have demonstrated that recurrent seizures induce hypoxia in cardiomyocytes, resulting in P-glycoprotein (P-gp) overexpression, prolonged Q-T interval, severe bradycardia, and hemosiderin precipitation, correlating with an elevated spontaneous death ratio. In this article, we explore the intricate connections among ferroptosis, epilepsy, and SUDEP. By synthesizing current knowledge and drawing insights from recent publications, this study provides a comprehensive understanding of the molecular underpinnings. Furthermore, this review offers insights into potential therapeutic avenues and outlines future research directions.

Patient and provider attitudes regarding sudden unexpected death in epilepsy disclosure at a low-resource, minority community health center.

BACKGROUND: Sudden Unexpected Death in Epilepsy (SUDEP) is a complication of epilepsy responsible for approximately 1 death per 1000 patients. The literature has demonstrated minimal SUDEP disclosure between providers and patients, although patients have consistently reported desire to know about their risk. However, the majority of these studies has been conducted in Caucasian populations which did not seek to include lower socio-economic class individuals. Thus, the purpose of this study is to determine patient and provider attitudes regarding SUDEP disclosure at a community health center serving minority, predominantly Hispanic, patients. METHODS: This cross-sectional study utilized surveys distributed to patients with epilepsy (n = 20), patients with diabetes (n = 20), those with no chronic disease (n = 20) and providers (n = 13). Online surveys were distributed to 13 providers whereas phone surveys were conducted for patients with epilepsy. In-person surveys were distributed to patients with diabetes and no chronic disease to serve as comparison groups. Surveys were available in both Spanish and English. Patient surveys consisted of demographic information and questions evaluating their current knowledge and preferences regarding disclosure of a potentially fatal disorder. RESULTS: Twenty patients with epilepsy, 20 patients with diabetes, 20 patients without chronic diseases, and 9 providers responded to the online or in-person surveys. Of the patients with epilepsy, 90 % (n = 18/20) were Hispanic which was not significantly different from the comparison groups. 45 % (n = 9/20) believed they had a higher rate of death due to epilepsy with only 3 patients having heard of SUDEP prior to the survey, and only 1 learning this from a physician. All patients wanted to know everything there was to know regarding their condition, including a higher risk of unexpected death. Most patients (85%, n = 17/20) believe everyone with epilepsy should be informed of SUDEP and this information should come from their provider (90 %, n = 18/20). Results were similar for both comparison groups, except patients with diabetes unanimously desired to know about a theoretical risk of death at the time of diagnosis. Of the providers, 66.7% (n = 6/9) never discuss SUDEP, with the remaining 33.3% (n = 3/9) discussing SUDEP rarely. The primary reason for not discussing SUDEP was not knowing enough about it (66.7%, n = 5/9). CONCLUSION: Almost all patients with epilepsy had no knowledge of SUDEP, yet desired to know this information within the first two visits. Providers in the primary care setting rarely discuss SUDEP, most often due to lack of knowledge. These results are very similar to those found in mainly white, higher socioeconomic populations and indicate that race should not be a barrier to SUDEP disclosure.

The influence of risk factors, biomarkers and care settings on SUDEP counseling.

Although sudden unexpected death in epilepsy (SUDEP) is the most feared epilepsy outcome, there is a dearth of SUDEP counseling provided by neurologists. This may reflect limited time, as well as the lack of guidance on the timing and structure for counseling. We evaluated records from SUDEP cases to examine frequency of inpatient and outpatient SUDEP counseling, and whether counseling practices were influenced by risk factors and biomarkers, such as post-ictal generalized EEG suppression (PGES). We found a striking lack of SUDEP counseling despite modifiable SUDEP risk factors; counseling was limited to outpatients despite many patients having inpatient visits within a year of SUDEP. PGES was inconsistently documented and was never included in counseling. There is an opportunity to greatly improve SUDEP counseling by utilizing inpatient settings and prompting algorithms incorporating risk factors and biomarkers.

Evaluation of Commercially Available Seizure Detection Wearables in Canada: Current Evidence.

Wearable-based seizure detection devices hold promise in reducing seizure-related adverse events and relieving the daily stress experienced by people with epilepsy. In this work, we present the latest evidence regarding the performance of three seizure detection wearables (eight studies) commercially available in Canada to provide guidance to clinicians. Overall, their ability to detect focal-to-bilateral and/or generalized tonic-clonic seizures ranges between 21.0% and 98.15% in sensitivity, with the 24h false alarm rates ranging from 0 to 1.28. While performance in epilepsy monitoring units show promise, the lack of evidence in outpatient settings precludes strong recommendations for their use in daily life.

Sudden unexpected death in epilepsy and ictal asystole in patients with autoimmune encephalitis: a systematic review.

OBJECTIVE: As autoimmune encephalitis (AE) often involves the mesial temporal structures which are known to be involved in both sudden unexpected death in epilepsy (SUDEP) and ictal asystole (IA), it may represent a good model to study the physiopathology of these phenomena. Herein, we systematically reviewed the occurrence of SUDEP and IA in AE. METHODS: We searched 4 databases (MEDLINE, Scopus, Embase, and Web of Science) for studies published between database inception and December 20, 2022, according to the PRISMA guidelines. We selected articles reporting cases of definite/probable/possible/near-SUDEP or IA in patients with possible/definite AE, or with histopathological signs of AE. RESULTS: Of 230 records assessed, we included 11 cases: 7 SUDEP/near-SUDEP and 4 IA. All patients with IA were female. The median age at AE onset was 30 years (range: 15-65), and the median delay between AE onset and SUDEP was 11 months; 0.9 months for IA. All the patients presented new-onset seizures, and 10/11 also manifested psychiatric, cognitive, or amnesic disorders. In patients with SUDEP, 2/7 were antibody-positive (1 anti-LGI1, 1 anti-GABABR); all IA cases were antibody-positive (3 anti-NMDAR, 1 anti-GAD65). Six patients received steroid bolus, 3 intravenous immunoglobulin, and 3 plasmapheresis. A pacemaker was implanted in 3 patients with IA. The 6 survivors improved after treatment. DISCUSSION: SUDEP and IA can be linked to AE, suggesting a role of the limbic system in their pathogenesis. IA tends to manifest in female patients with temporal lobe seizures early in AE, highlighting the importance of early diagnosis and treatment.

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.