Sleep and epilepsy

Lateralizing value of interictal epileptiform discharges and other parameters in hypothalamic hamartoma

OBJECTIVE

Hypothalamic hamartomas (HHs) are associated with pharmacoresistant epilepsy. Stereotactic radiofrequency thermocoagulation (SRT) shows promise as a disconnecting intervention. Although magnetic resonance imaging (MRI) is typically used to determine the attachment and intervention side, it presents challenges in cases of bilaterally attached HH, where the epileptogenic side is unclear. The lateralizing potential of electroclinical parameters in such cases remains uncertain. This retrospective study evaluates the lateralization value of specific parameters, particularly in patients with unilateral HH, to improve future diagnostics and treatment approaches for bilateral HH.

METHODS

Four lateralizing parameters-semiology, ictal electroencephalography (EEG), and interictal epileptiform discharges during awake (IEDsw) and sleep states (IEDss)-were assessed for correlation with HH attachment side using Spearman's ρ. We calculated areas under the curves (AUCs) and cutoffs for left and right IEDs prognostic lateralizing value, plotting differences between IEDsright and IEDsleft in a receiver-operating characteristic(ROC) curve to establish the required preponderance of unilateral IEDss to differentiate between left and right HHs. Binomial logistic regression was employed to predict the HH attachment side.

RESULTS

We included 25 patients (2-55 years of age) with mainly unilateral (n = 22) HHs who underwent SRT and presurgical evaluation. All parameters correlated with HH attachment side (semiology R = -.62, p = .005; ictal EEG R = .51, p = .047; IEDs R = .55, p = .018; IEDw, R = .61, p = .018). AUC values for right and left IEDs were .76 (p = .047) and .85 (p = .019), respectively, with cutoffs of .34 and .15. The AUC for "IEDsright-IEDsleft" was .98 (p = .0018) with a cutoff of .16. IEDss and semiology were significant predictors, achieving 88% correct lateralization.

SIGNIFICANCE

IEDss are promising biomarkers for HH lateralization in unilateral HH. The predominance of unilateral IEDss suggests ipsilateral HH. Even in cases with predominantly bilateral IEDss, a slight preponderance of unilateral IEDss can indicate the attachment side. In addition, combining IEDss and semiology provides a predictive model for HH lateralization.

Voltage Gated Ion Channels and Sleep

Ion channels are integral components of the nervous system, playing a pivotal role in shaping membrane potential, neuronal excitability, synaptic transmission and plasticity. Dysfunction in these channels, such as improper expression or localization, can lead to irregular neuronal excitability and synaptic communication, which may manifest as various behavioral abnormalities, including disrupted rest-activity cycles. Research has highlighted the significant impact of voltage gated ion channels on sleep parameters, influencing sleep latency, duration and waveforms. Furthermore, these ion channels have been implicated in the vulnerability to, and the pathogenesis of, several neurological and psychiatric disorders, including epilepsy, autism, schizophrenia, and Alzheimer's disease (AD). In this comprehensive review, we aim to provide a summary of the regulatory role of three predominant types of voltage-gated ion channels-calcium (Ca2+), sodium (Na+), and potassium (K+)-in sleep across species, from flies to mammals. We will also discuss the association of sleep disorders with various human diseases that may arise from the dysfunction of these ion channels, thereby underscoring the potential therapeutic benefits of targeting specific ion channel subtypes for sleep disturbance treatment.

Mortality in older adults with epilepsy: An understudied entity

Despite the recognition of Sudden Unexpected Death in Epilepsy (SUDEP) and other risks of premature mortality in people with epilepsy (PWE), mortality in older PWE remains an understudied entity. This review provides a comprehensive overview of the multifaceted causes of premature mortality in older adults with epilepsy and emphasizes the need for targeted interventions to reduce mortality and enhance the quality of life in this vulnerable population. It underscores the heightened prevalence of epilepsy among older adults and the interplay of intrinsic and extrinsic factors contributing to their mortality. Further, this paper delves into the nuances of diagnosing SUDEP in older adults and the underestimation of its incidence due to misclassification and lack of standardized protocols. Factors such as frailty, comorbidities, and the bidirectional relationship between epilepsy and conditions such as dementia and stroke further compound the mortality risks. Key factors, including status epilepticus, comorbid conditions (such as cardiovascular diseases, cerebrovascular events, and neurodegenerative disorders), and external causes like accidents, falls, and suicide, are discussed. It also examines the implications of anti-seizure medications, particularly polypharmacy, and their adverse effects on this population. Future directions include implementing enhanced diagnostic protocols, developing treatment plans, and integrating real-time monitoring technologies to reduce the risk of sudden death and multifaceted premature mortality in this patient population. Increasing awareness among healthcare providers and families about the risks and management of epilepsy in older adults, along with fostering collaborative research efforts, is essential to improve mortality outcomes. PLAIN LANGUAGE SUMMARY: There is a heightened risk of mortality in older people with epilepsy due to many causes unique to their population. Despite the risk, Sudden Unexpected Death in Epilepsy and early mortality in older adults with epilepsy are underestimated. Unique contributing factors include comorbid conditions like dementia, stroke, and frailty, adverse effects from polypharmacy, and increased risks of cardiovascular complications and external injuries such as falls and suicide. A careful consideration of all these factors can help mitigate the mortality in older adults with epilepsy.

Sleep apnea, hypoxia, and late-onset epilepsy: the Atherosclerosis Risk in Communities study

STUDY OBJECTIVE

Sleep apnea is associated with unexplained epilepsy in older adults in small studies. We sought to determine the relationship between sleep apnea and additional sleep characteristics and late-onset epilepsy (LOE), adjusting for comorbidities, using data from the large, prospective Atherosclerosis Risk in Communities (ARIC) Study cohort.

METHODS

We used Medicare claims to identify cases of LOE in ARIC participants. We used polysomnography data from 1309 ARIC participants who also participated in the Sleep Heart Health Study in 1995-1998, and demographic and comorbidity data from ARIC. Later risk of LOE was evaluated using survival analysis with a competing risk of death. We also used survival analysis in 2672 ARIC participants to identify the association between self-reported obstructive sleep apnea (2011-2013), and the risk of subsequent LOE.

RESULTS

Late-midlife oxygen desaturation to less than 80% during sleep was associated with subsequent development of LOE, adjusted subhazard ratio 3.28 (1.18-9.08), but the apnea-hypopnea index was not related. Participant report of diagnosis of sleep apnea in 2011-2013 was also associated with subsequent LOE, adjusted subhazard ratio 2.59 (1.24-5.39).

CONCLUSIONS

Sleep apnea and oxygen saturation nadir during sleep are associated with LOE, independently of hypertension and other comorbidities. These potentially modifiable risk factors could have large clinical implications for LOE.

Factors Affecting the Activation and Appearances of Epileptiform Abnormalities in Routine Electroencephalography by Different Provocation Methods

OBJECTIVE

The objective of this study was to observe the effects of various clinical factors on the activation and appearance of epileptiform abnormalities (EAs) in routine electroencephalography (rEEG) by different provocation methods.

METHODS

This observational study involved a review of 136 patients presented for EEG recording due to various indications and their EEG showing EAs during various provocation methods.

RESULTS

Generalized spike-wave discharges (GSWDs) were the most frequent activated epileptiform pattern observed in, 81 (59.1%) recordings. This pattern was seen mainly in females 49 (P = 0.00), in patients with generalized seizures 48 (P = 0.00), in prolonged EEG records 3 (P = 0.03), and in both genetic 35 (P = 0.00) and lesional epilepsies 21 (P = 0.00). Focal sharp waves with bilateral synchrony (FSWSBS) were the most activated ictal pattern (P = 0.00). Ictal EAs after hyperventilation (HV) (P = 0.03) and intermittent photic stimulation (IPS) (P = 0.01) were mainly observed in patients with uncontrolled seizures (P = 0.00), and immune-mediated epilepsy (P = 0.02). Females sex (odds ratio [OR]: 1.33, confidence interval [CI]: 0.6-2.6; P = 0.25), bilateral tonic-clonic seizures (OR: 1.17, CI: 0.5-2.4; P = 0.31) and lesional epilepsies (OR: 1.45, CI: 0.7-2.9; P = 0.20) had risk of activation of EAs by provocation methods; however this risk was not statistically significant. While sleep deprivation (SD) (OR: 6.33, CI: 2.2-18.2; P = 0.00), nonrapid eye movement sleep (NREM) (OR: 2.41, CI: 1.0-5.4; P = 0.00), and prolong EEG recording (OR: 1.91, CI: 0.9-3.9; P = 0.04) were leading to a statistically significant risk of activation and appearances of EAs due to provocation.

CONCLUSION

Different provocation methods can activate and augment the variety of EEG patterns of diverse clinical significance. Detection of activated ictal EAs is dependent on various patient factors, including seizure control, and the provocation method applied. Further larger prospective cohort studies with adequate sample sizes are warranted.

Neural hyperexcitability in Angelman syndrome: Genetic factors and pharmacologic treatment approaches

Angelman syndrome (AS) is a rare neurodevelopmental disorder that is typically caused by deletion or a loss-of-function mutation of the maternal copy of the ubiquitin ligase E3A (UBE3A) gene. The disorder is characterized by severe intellectual disability, deficits in speech, motor abnormalities, altered electroencephalography (EEG) activity, spontaneous epileptic seizures, sleep disturbances, and a happy demeanor with frequent laughter. Regarding electrophysiologic abnormalities in particular, enhanced delta oscillatory power and an elevated excitatory/inhibitory (E/I) ratio have been documented in AS, with E/I ratio especially studied in rodent models. These electrophysiologic characteristics appear to relate with the greatly elevated rates of epilepsy in individuals with AS, and associated hypersynchronous neural activity. Here we briefly review findings on EEG, E/I ratio, and epileptic seizures in AS, including data from rodent models of the disorder. We summarize pharmacologic approaches that have been used to treat behavioral aspects of AS, including neuropsychiatric phenomena and sleep disturbances, as well as seizures in the context of the disorder. Antidepressants such as SSRIs and atypical antipsychotics are among the medications that have been used behaviorally, whereas anticonvulsant drugs such as valproic acid and lamotrigine have frequently been used to control seizures in AS. We end by suggesting novel uses for some existing pharmacologic agents in AS, including noradrenergic transmission reducing drugs (alpha2 agonists, beta blockers, alpha1 antagonists) and cholinesterase inhibitors, where these various classes of drugs may have the ability to ameliorate both behavioral disturbances and seizures.

Visualization of the Spatiotemporal Propagation of Interictal Spikes in Temporal Lobe Epilepsy: A MEG Pilot Study

Magnetoencephalography (MEG) is clinically used to localize interictal spikes in discrete brain areas of epilepsy patients through the equivalent current dipole (ECD) method, but does not account for the temporal dynamics of spike activity. Recent studies found that interictal spike propagation beyond the temporal lobe may be associated with worse postsurgical outcomes, but studies using whole-brain data such as in MEG remain limited. In this pilot study, we developed a tool that visualizes the spatiotemporal dynamics of interictal MEG spikes normalized to spike-free sleep activity to assess their onset and propagation patterns in patients with temporal lobe epilepsy (TLE). We extracted interictal source data containing focal epileptiform activity in awake and asleep states from seven patients whose MEG ECD clusters localized to the temporal lobe and normalized the data against spike-free sleep recordings. We calculated the normalized activity over time per cortical label, confirmed maximal activity at onset, and mapped the activity over a 10 ms interval onto each patient's brain using a custom-built Multi-Modal Visualization Tool. The onset of activity in all patients appeared near the clinically determined epileptogenic zone. By 10 ms, four of the patients had propagated source activity restricted to within the temporal lobe, and three had propagated source activity spread to extratemporal regions. Using this tool, we show that noninvasively identifying the onset and propagation of interictal spike activity in MEG can be achieved, which may help provide further insight into epileptic networks and guide surgical planning and interventions in patients with TLE.

Shorter duration of slow wave sleep is related to symptoms of depression in patients with epilepsy

Slow wave sleep duration and spectral abnormalities are related to both epilepsy and depression, but it is unclear how depressive symptoms in patients with epilepsy are affected by slow wave sleep duration and clinical factors, and how the spectral characteristics of slow wave sleep reflect a potential interaction of epilepsy and depression. Long-term video-EEG monitoring was conducted in 51 patients with focal epilepsy, 13 patients with generalized epilepsy, and 9 patients without epilepsy. Slow wave sleep segments were manually marked in the EEG and duration as well as EEG power spectra were extracted. Depressive symptoms were documented with the Beck Depression Inventory (BDI). At least mild depressive symptoms (BDI > 9) were found among 23 patients with focal epilepsy, 5 patients with generalised epilepsy, and 6 patients who had no epilepsy diagnosis. Slow wave sleep duration was shorter for patients with at least mild depressive symptoms (p =.004), independently from epilepsy diagnosis, antiseizure medication, age, and sex. Psychoactive medication was associated with longer slow wave sleep duration (p =.008). Frontal sigma band power (13-15 Hz) during slow wave sleep was higher for patients without epilepsy and without depressive symptoms as compared to patients without depressive symptoms but with focal epilepsy (p =.005). Depressive symptoms affect slow wave sleep duration of patients with epilepsy similarly as in patients without epilepsy. Since reduced slow wave sleep can increase the likelihood of seizure occurrence, these results stress the importance of adequate treatment for patients with epilepsy who experience depressive symptoms.

Subclinical epileptiform activity and sleep disturbances in Alzheimer's disease

INTRODUCTION

Subclinical epileptiform activity (SEA) and sleep disturbances are frequent in Alzheimer's disease (AD). Both have an important relation to cognition and potential therapeutic implications. We aimed to study a possible relationship between SEA and sleep disturbances in AD.

METHODS

In this cross-sectional study, we performed a 24-h ambulatory EEG and polysomnography in 48 AD patients without diagnosis of epilepsy and 34 control subjects.

RESULTS

SEA, mainly detected in frontotemporal brain regions during N2 with a median of three spikes/night [IQR1-17], was three times more prevalent in AD. AD patients had lower sleep efficacy, longer wake after sleep onset, more awakenings, more N1%, less REM sleep and a higher apnea-hypopnea index (AHI) and oxygen desaturation index (ODI). Sleep was not different between AD subgroup with SEA (AD-Epi+) and without SEA (AD-Epi-); however, compared to controls, REM% was decreased and AHI and ODI were increased in the AD-Epi+ subgroup.

DISCUSSION

Decreased REM sleep and more severe sleep-disordered breathing might be related to SEA in AD. These results could have diagnostic and therapeutic implications and warrant further study at the intersection between sleep and epileptiform activity in AD.

Resting-state background features demonstrate multidien cycles in long-term EEG device recordings

BACKGROUND

Longitudinal EEG recorded by implanted devices is critical for understanding and managing epilepsy. Recent research reports patient-specific, multi-day cycles in device-detected epileptiform events that coincide with increased likelihood of clinical seizures. Understanding these cycles could elucidate mechanisms generating seizures and advance drug and neurostimulation therapies.

OBJECTIVE/HYPOTHESIS

We hypothesize that seizure-correlated cycles are present in background neural activity, independent of interictal epileptiform spikes, and that neurostimulation may temporarily interrupt these cycles.

METHODS

We analyzed regularly-recorded seizure-free data epochs from 20 patients implanted with a responsive neurostimulation (RNS) device for at least 1.5 years, to explore the relationship between cycles in device-detected interictal epileptiform activity (dIEA), clinician-validated interictal spikes, background EEG features, and neurostimulation.

RESULTS

Background EEG features tracked the cycle phase of dIEA in all patients (AUC: 0.63 [0.56-0.67]) with a greater effect size compared to clinically annotated spike rate alone (AUC: 0.55 [0.53-0.61], p < 0.01). After accounting for circadian variation and spike rate, we observed significant population trends in elevated theta and beta band power and theta and alpha connectivity features at the cycle peaks (sign test, p < 0.05). In the period directly after stimulation we observe a decreased association between cycle phase and EEG features compared to background recordings (AUC: 0.58 [0.55-0.64]).

CONCLUSIONS

Our findings suggest that seizure-correlated dIEA cycles are not solely due to epileptiform discharges but are associated with background measures of brain state; and that neurostimulation may temporarily interrupt these cycles. These results may help elucidate mechanisms underlying seizure generation, provide new biomarkers for seizure risk, and facilitate monitoring, treating, and managing epilepsy with implantable devices.

Abnormal Topological Organization of Structural Covariance Networks in Patients with Temporal Lobe Epilepsy Comorbid Sleep Disorder

OBJECTIVE

The structural covariance network (SCN) alterations in patients with temporal lobe epilepsy and comorbid sleep disorder (PWSD) remain poorly understood. This study aimed to investigate changes in SCNs using structural magnetic resonance imaging.

METHODS

Thirty-four PWSD patients, thirty-three patients with temporal lobe epilepsy without sleep disorder (PWoSD), and seventeen healthy controls underwent high-resolution structural MRI imaging. Subsequently, SCNs were constructed based on gray matter volume and analyzed via graph-theoretical approaches.

RESULTS

PWSD exhibited significantly increased clustering coefficients, shortest path lengths, transitivity, and local efficiency. In addition, various distributions and numbers of SCN hubs were identified in PWSD. Furthermore, PWSD networks were less robust to random and target attacks than those of healthy controls and PWoSD patients.

CONCLUSION

This study identifies aberrant SCN changes in PWSD that may be related to the susceptibility of patients with epilepsy to sleep disorders.

Nonconvulsive Status Epilepticus With Generalized Spike-and-Wave Discharges: Pathophysiological and Nosological Considerations

Absence status epilepticus (ASE) is the most common type of status epilepticus in patients with idiopathic generalized epilepsy (IGE). Like absence seizure, ASE is characterized by generalized spike-and-wave discharges (GSWDs) on the electroencephalogram (EEG). Once considered specific for IGE, GSWDs have increasingly been observed in other forms of epilepsy, as well as in patients with no prior epilepsy. Here, we report three patients with different types of nonconvulsive status epilepticus (NCSE) in which the EEG correlate was GSWDs: a 44-year-old woman with juvenile absence epilepsy who manifested ASE, a 73-year-old woman with anoxic brain injury complicated by NCSE with well-formed GSWDs (as seen in IGE and de novo ASE), and a 41-year-old woman with frontal lobe epilepsy who developed focal NCSE with impaired consciousness. Evidently, patients with generalized epilepsy, focal epilepsy, and no prior epilepsy can all manifest NCSE with similar electroclinical characteristics, i.e., GSWDs and impaired consciousness. This observation adds to the existing evidence that seizures, whether classified as focal or generalized, often involve focal and generalized elements in their pathophysiology. To fully understand seizure pathophysiology, we must steer away from the focal-versus-generalized paradigm that has dominated the nosology of seizures and epilepsy for a very long time.

Analogous cortical reorganization accompanies entry into states of reduced consciousness during anesthesia and sleep

Theories of consciousness suggest that brain mechanisms underlying transitions into and out of unconsciousness are conserved no matter the context or precipitating conditions. We compared signatures of these mechanisms using intracranial electroencephalography in neurosurgical patients during propofol anesthesia and overnight sleep and found strikingly similar reorganization of human cortical networks. We computed the "effective dimensionality" of the normalized resting state functional connectivity matrix to quantify network complexity. Effective dimensionality decreased during stages of reduced consciousness (anesthesia unresponsiveness, N2 and N3 sleep). These changes were not region-specific, suggesting global network reorganization. When connectivity data were embedded into a low-dimensional space in which proximity represents functional similarity, we observed greater distances between brain regions during stages of reduced consciousness, and individual recording sites became closer to their nearest neighbors. These changes corresponded to decreased differentiation and functional integration and correlated with decreases in effective dimensionality. This network reorganization constitutes a neural signature of states of reduced consciousness that is common to anesthesia and sleep. These results establish a framework for understanding the neural correlates of consciousness and for practical evaluation of loss and recovery of consciousness.

Sleep and seizure risk in epilepsy: bed and wake times are more important than sleep duration

Sleep duration, sleep deprivation and the sleep-wake cycle are thought to play an important role in the generation of epileptic activity and may also influence seizure risk. Hence, people diagnosed with epilepsy are commonly asked to maintain consistent sleep routines. However, emerging evidence paints a more nuanced picture of the relationship between seizures and sleep, with bidirectional effects between changes in sleep and seizure risk in addition to modulation by sleep stages and transitions between stages. We conducted a longitudinal study investigating sleep parameters and self-reported seizure occurrence in an ambulatory at-home setting using mobile and wearable monitoring. Sixty subjects wore a Fitbit smartwatch for at least 28 days while reporting their seizure activity in a mobile app. Multiple sleep features were investigated, including duration, oversleep and undersleep, and sleep onset and offset times. Sleep features in participants with epilepsy were compared to a large (n = 37 921) representative population of Fitbit users, each with 28 days of data. For participants with at least 10 seizure days (n = 34), sleep features were analysed for significant changes prior to seizure days. A total of 4956 reported seizures (mean = 83, standard deviation = 130) and 30 485 recorded sleep nights (mean = 508, standard deviation = 445) were included in the study. There was a trend for participants with epilepsy to sleep longer than the general population, although this difference was not significant. Just 5 of 34 participants showed a significant difference in sleep duration the night before seizure days compared to seizure-free days. However, 14 of 34 subjects showed significant differences between their sleep onset (bed) and/or offset (wake) times before seizure occurrence. In contrast to previous studies, the current study found undersleeping was associated with a marginal 2% decrease in seizure risk in the following 48 h (P < 0.01). Nocturnal seizures were associated with both significantly longer sleep durations and increased risk of a seizure occurring in the following 48 h. Overall, the presented results demonstrated that day-to-day changes in sleep duration had a minimal effect on reported seizures, while patient-specific changes in bed and wake times were more important for identifying seizure risk the following day. Nocturnal seizures were the only factor that significantly increased the risk of seizures in the following 48 h on a group level. Wearables can be used to identify these sleep-seizure relationships and guide clinical recommendations or improve seizure forecasting algorithms.

Spike patterns surrounding sleep and seizures localize the seizure-onset zone in focal epilepsy

OBJECTIVE

Interictal spikes help localize seizure generators as part of surgical planning for drug-resistant epilepsy. However, there are often multiple spike populations whose frequencies change over time, influenced by brain state. Understanding state changes in spike rates will improve our ability to use spikes for surgical planning. Our goal was to determine the effect of sleep and seizures on interictal spikes, and to use sleep and seizure-related changes in spikes to localize the seizure-onset zone (SOZ).

METHODS

We performed a retrospective analysis of intracranial electroencephalography (EEG) data from patients with focal epilepsy. We automatically detected interictal spikes and we classified different time periods as awake or asleep based on the ratio of alpha to delta power, with a secondary analysis using the recently published SleepSEEG algorithm. We analyzed spike rates surrounding sleep and seizures. We developed a model to localize the SOZ using state-dependent spike rates.

RESULTS

We analyzed data from 101 patients (54 women, age range 16-69). The normalized alpha-delta power ratio accurately classified wake from sleep periods (area under the curve = .90). Spikes were more frequent in sleep than wakefulness and in the post-ictal compared to the pre-ictal state. Patients with temporal lobe epilepsy had a greater wake-to-sleep and pre- to post-ictal spike rate increase compared to patients with extra-temporal epilepsy. A machine-learning classifier incorporating state-dependent spike rates accurately identified the SOZ (area under the curve = .83). Spike rates tended to be higher and better localize the seizure-onset zone in non-rapid eye movement (NREM) sleep than in wake or REM sleep.

SIGNIFICANCE

The change in spike rates surrounding sleep and seizures differs between temporal and extra-temporal lobe epilepsy. Spikes are more frequent and better localize the SOZ in sleep, particularly in NREM sleep. Quantitative analysis of spikes may provide useful ancillary data to localize the SOZ and improve surgical planning.

[Alternative methods of therapy for comorbid sleep disorders as a method of choice in adult patients with epilepsy]

OBJECTIVE

Systematization and generalization of data from domestic and foreign literature on alternative methods of treatment of sleep disorders in epilepsy.

MATERIAL AND METHODS

The search for data from domestic and foreign literary sources was carried out in the electronic databases Medline (PubMed), Scopus, Web of Science, eLibrary, CyberLeninka, Google Scholar.

RESULTS

The data of modern randomized trials, meta-analyzes on the effectiveness of various non-traditional methods as a method of choice for epilepsy with comorbid sleep disorders have been analyzed.

CONCLUSIONS

Complementary (alternative) treatments have many advantages over the classical pharmacotherapy of sleep disorders in epilepsy, in the form of non-invasiveness, low incidence of side-effects, ease of use, and lack of a dose-dependent effect. Of course, the targets of most of the above methods are not focused and not very specific, and the sample size is too small to obtain impartial and meaningful clinical conclusions, but this once again emphasizes the urgent need for large-scale clinical trials, which is necessary to develop evidence-based treatments for comorbid sleep disorders in epilepsy.

Effect of Epilepsy on Sleep Quality During Pregnancy and Postpartum

BACKGROUND AND OBJECTIVES

This study seeks to understand how sleep is affected in pregnant women with epilepsy (WWE) relative to healthy pregnant women during pregnancy and postpartum and to nonpregnant WWE during comparative periods. Sleep affects maternal health and mood during pregnancy. Maternal sleep disturbances are related to poor fetal growth and increased fetal deaths. Epilepsy is the most common neurologic condition in pregnancy. Sleep disruption can worsen epileptic seizures. The interplay between epilepsy, pregnancy, and sleep is poorly understood.

METHODS

The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) study is an NIH-funded, prospective, observational, multicenter study, enrolling women from December 2012 through January 2016. Sleep quality was assessed using the average Pittsburgh Sleep Quality Index collected during pregnancy, postpartum, or analogous periods. Sleep scores range from 0 to 21 with higher scores indicating worse sleep quality; scores >5 are associated with poor sleep quality.

RESULTS

Of 351 pregnant WWE, 105 healthy pregnant women, and 109 nonpregnant WWE enrolled in the MONEAD study, data from 241 pregnant WWE, 74 healthy pregnant women, and 84 nonpregnant WWE were analyzed. Pregnant WWE had worse sleep (a higher mean sleep score) during pregnancy compared with healthy pregnant women in unadjusted analysis (p = 0.006), but no longer significant in adjusted analysis (p = 0.062); pregnant WWE (least square mean sleep score [95% CI] = 5.8 [5.5-6.1]) vs healthy pregnant women (5.1 [4.6-5.7]). During postpartum period, WWE (5.6 [5.4-5.9]) had similarly impaired sleep compared with healthy women (5.7 [5.2-6.2]; adjusted p = 0.838). Sleep was significantly worse in pregnant WWE vs nonpregnant WWE (for comparable period) in pregnancy and postpartum in unadjusted and adjusted analyses; adjusted scores for pregnant WWE in pregnancy (5.7 [5.4-6.0]) and those in postpartum (5.7 [5.4-6.0]) compared with those for nonpregnant WWE (4.7 [4.2-5.3]; p = 0.002) and (4.1 [3.6-4.7]; p < 0.001), respectively. Sleep quality between pregnancy and postpartum varied only in healthy pregnant women (change in mean score = 0.8 [0.2-1.3]; p = 0.01), whose sleep was worse in postpartum.

DISCUSSION

Pregnant WWE had worse sleep during pregnancy and postpartum period than nonpregnant WWE during comparable periods in the adjusted analysis.

TRIAL REGISTRATION INFORMATION

The study is registered at ClinicalTrials.gov as NCT01730170.

Chronobiology of epilepsy and sudden unexpected death in epilepsy

Epilepsy is a neurological disease characterized by spontaneous, unprovoked seizures. Various insults render the brain hyperexcitable and susceptible to seizure. Despite there being dozens of preventative anti-seizure medications available, these drugs fail to control seizures in nearly 1 in 3 patients with epilepsy. Over the last century, a large body of evidence has demonstrated that internal and external rhythms can modify seizure phenotypes. Physiologically relevant rhythms with shorter periodic rhythms, such as endogenous circadian rhythms and sleep-state, as well as rhythms with longer periodicity, including multidien rhythms and menses, influence the timing of seizures through poorly understood mechanisms. The purpose of this review is to discuss the findings from both human and animal studies that consider the effect of such biologically relevant rhythms on epilepsy and seizure-associated death. Patients with medically refractory epilepsy are at increased risk of sudden unexpected death in epilepsy (SUDEP). The role that some of these rhythms play in the nocturnal susceptibility to SUDEP will also be discussed. While the involvement of some of these rhythms in epilepsy has been known for over a century, applying the rhythmic nature of such phenomenon to epilepsy management, particularly in mitigating the risk of SUDEP, has been underutilized. As our understanding of the physiological influence on such rhythmic phenomenon improves, and as technology for chronic intracranial epileptiform monitoring becomes more widespread, smaller and less invasive, novel seizure-prediction technologies and time-dependent chronotherapeutic seizure management strategies can be realized.

Chronic recording of the vagus nerve to analyze modulations by the light-dark cycle

OBJECTIVE

The vagus nerve is considered to play a key role in the circadian rhythm. Chronic continuous analysis of the vagus nerve activity could contribute to a better understanding of the role of the vagus nerve in light-dark modulations. This paper presents a continuous analysis of spontaneous vagus nerve activity performed in four rats.

APPROACH

We analyzed the vagus electroneurogram (VENG) and electroencephalogram (EEG) over a recording period of 28 days. Spike activity and heart rate estimation were derived from the VENG, and slow-wave activity was derived from the EEG. The presence of repetitive patterns was investigated with periodograms, cosinor fitting, autocorrelation, and statistical tests. The light-dark variations derived from the VENG spikes were compared with EEG slow waves, an established metric in circadian studies.

RESULTS

Our results demonstrate that light-dark variations can be detected in long-term vagus nerve activity monitoring. A recording period of about seven days is required to characterize accurately the VENG light-dark variations.

SIGNIFICANCE

As a major outcome of this study, vagus nerve recordings hold the promise to help understand circadian regulation.

The role of monoaminergic neurons in modulating respiration during sleep and the connection with SUDEP

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death among epilepsy patients, occurring even more frequently in cases with anti-epileptic drug resistance. Despite some advancements in characterizing SUDEP, the underlying mechanism remains incompletely understood. This review summarizes the latest advances in our understanding of the pathogenic mechanisms of SUDEP, in order to identify possible targets for the development of new strategies to prevent SUDEP. Based on our previous research along with the current literature, we focus on the role of sleep-disordered breathing (SDB) and its related neural mechanisms to consider the possible roles of monoaminergic neurons in the modulation of respiration during sleep and the occurrence of SUDEP. Overall, this review suggests that targeting the monoaminergic neurons is a promising approach to preventing SUDEP. The proposed roles of SDB and related monoaminergic neural mechanisms in SUDEP provide new insights for explaining the pathogenesis of SUDEP.

Evaluation of Sleep Disturbances in Patients with Nocturnal Epileptic Seizures in a Romanian Cross-Sectional Study

(1) Background: Based on the premise that epilepsy is frequently associated with hypnopathies, in this study we aim to analyze the prevalence of sleep disturbances among patients with epilepsy, with exclusively or predominantly nocturnal seizures, in relation to demographic factors as well as clinical and electroencephalography (EEG) aspects. (2) Methods: 69 patients with nocturnal epilepsy were included in our study. Sleep disturbances were measured with the Pittsburgh Sleep Quality Index (PSQI) questionnaire, followed by a long-term video-EEG monitoring during sleep. We analyzed the PSQI results in relation to patients' gender and age and determined the correlations between the PSQI scores and the modifications on video-EEG recordings, in comparison to a control group of 25 patients with epilepsy but without nocturnal seizures. (3) Results: We found a statistically significant difference between the PSQI of patients with nocturnal seizures compared to those without nocturnal epileptic manifestations. In the experimental group, the mean PSQI score was 7.36 ± 3.91 versus 5.04 ± 2.56 in controls. In women, the average PSQI score was 8.26, whilst in men it only reached 6.41, highlighting a statistically significant difference between genders (p ˂ 0.01). By examining the relationships between the PSQI scores and certain sleep-related factors, evidenced on the nocturnal video-EEG, we found a statistically significant difference between PSQI values of patients who reached the N2 stage, and those who reached the N3 stage of nonrapid eye movement (NREM) sleep, highlighting that those with a more superficial nocturnal sleep also had higher PSQI scores. There were no statistically significant differences regarding the PSQI scores between patients with or without interictal epileptiform discharges, and also in the few patients with nocturnal seizures where we captured ictal activity. (4) Conclusions: we evidenced in this study a poor quality of sleep in patients with nocturnal epilepsy, mostly in women, independent of age. We observed that sleep disturbances were due to superficial and fragmented sleep with frequent microarousals, not necessarily caused by the electrical epileptiform activity.

Changes in Pre- and Postsurgery for Drug Resistant Epilepsy: Cognition and Sleep

BACKGROUND

Most patients with drug-resistant epilepsy (DRE) have cognitive impairment and sleep disturbance. There was a significant correlation between sleep disorders and cognitive dysfunction. This study performed surgical treatment on patients with DRE and observed seizures, sleep, and cognition in patients with DRE in 6th month after operation to clarify the correlation between sleep and cognition in DRE patients.

METHODS

21 individuals with DRE were recruited to enroll in this trial. Each participant completed epileptic focus resection. Seizure frequency was the principle index; the mean seizure frequency was 1 month before surgery and six months after surgery. Cognitive function was assessed by MMSE, and sleep status was assessed by PSQI and ActiGraph; assessments were performed before and 6 months after surgery.

RESULTS

There were significant differences between conditions on all outcome measures; after 6 months of surgery, compared with before treatment, the monthly average seizure frequency of DRE decreased, which was statistically significant (P < 0.001) compared with that before treatment. The MMSE score of DRE patients was significantly higher than before (P < 0.01), especially the ability of attention, calculation, and recall in MMSE score, which was significantly higher than before operation (respectively, P < 0.001 and P < 0.01). The subjective sleep evaluation index PSQI and objective measurement of sleep latency, total sleep time, and sleep efficiency of patients with DRE by ActiGraph were statistically significant (respectively, P < 0.01) compared with that before treatment. There was a correlation between seizure frequency and MMSE (r = -0.8887, P < 0.0001), PSQI (0.5515, P < 0.01), sleep latency (0.5353, P < 0.05), total sleep time (-0.7814, P < 0.0001), and sleep efficiency (-0.4380, P < 0.05).

CONCLUSIONS

Surgery can effectively reduce the epileptic seizures frequency in patients with DRE and indirectly improve the computational power, attention, recall ability, and sleep status of patients. However, this result did not show a correlation between improved cognitive function and sleep, so the patient's cognitive function may be caused by surgery to improve the frequency of seizures. So, whether the improvement of patients' sleep conditions can also significantly improve the frequency of attacks and cognitive function in patients with DRE needs further exploration.

Gut microbiome effects on neuronal excitability & activity: Implications for epilepsy

It is now well established that the bacterial population of the gastrointestinal system, known as the gut microbiome, is capable of influencing the brain and its dependent functions. Links have been demonstrated between the microbiome and a variety of normal and pathological neural functions, including epilepsy. Many of these microbiome-brain links involve the direct or indirect modulation of the excitability and activity of individual neurons by the gut microbiome. Such links may be particularly significant when it comes to microbiome modulation of epilepsy, often considered a disorder of neuronal excitability. In this review we consider the current evidence of a relationship between the gut microbiome and the excitability or activity of neurons in the context of epilepsy. The review focuses particularly on evidence of direct, causal microbiome effects on neuronal excitability or activity, but also considers demonstrations of microbiome to host interactions that are likely to have an indirect influence. While we identify a few common themes, it is apparent that deriving general mechanistic principles of microbiome influence on these parameters in epilepsy will require considerable further study to tease out the many interacting factors, systems, and conditions.

Physical and mental health comorbidities of patients with epilepsy in Germany - A retrospective cohort study

AIMS

The aim of this study was to estimate the prevalence of physical and psychological comorbidities in patients with epilepsy in Germany in order to better understand the complex clinical picture and its consequences.

METHODS

This retrospective cohort study included adult individuals with a diagnosis of epilepsy between January 2018 and December 2018 (index date). Patients with epilepsy were matched 1:1 with patients without epilepsy by age, sex, and physician. The study outcomes included the associations between epilepsy and different physical and mental disorders documented within 365 days after the index date as well as multimorbidity defined as at least two, three, four, and five different diagnoses. The present study used multivariate logistic regression models with all study disorders as dependent variables and epilepsy as an impact variable.

RESULTS

After 1:1 matching, the present study included 7942 patients with and 7942 patients without epilepsy (mean age: 58.0 years; 49.7% female). Epilepsy was significantly positively associated with nine disorders, and the strongest associations were with mental retardation (Odds Ratio (OR): 21.11 (95% Confidence Intervals (CI): 12.52-35.59)), cerebrovascular diseases (OR: 3.14 (95% CI: 2.80-3.55)), and dementia (OR: 1.72 (95% CI: 1.47-2.01)). Epilepsy was associated with significantly increased odds of multimorbidity.

CONCLUSION

In summary, individuals with epilepsy have an increased prevalence of comorbidities that increase with age. Further research should be undertaken in this area, including the etiology of comorbidities.

The Reciprocal Interaction Between Sleep and Alzheimer's Disease

It is becoming increasingly recognized that patients with a variety of neurodegenerative diseases exhibit disordered sleep/wake patterns. While sleep impairments have typically been thought of as sequelae of underlying neurodegenerative processes in sleep-wake cycle regulating brain regions, including the brainstem, hypothalamus, and basal forebrain, emerging evidence now indicates that sleep deficits may also act as pathophysiological drivers of brain-wide disease progression. Specifically, recent work has indicated that impaired sleep can impact on neuronal activity, brain clearance mechanisms, pathological build-up of proteins, and inflammation. Altered sleep patterns may therefore be novel (potentially reversible) dynamic functional markers of proteinopathies and modifiable targets for early therapeutic intervention using non-invasive stimulation and behavioral techniques. Here we highlight research describing a potentially reciprocal interaction between impaired sleep and circadian patterns and the accumulation of pathological signs and features in Alzheimer's disease, the most prevalent neurodegenerative disease in the elderly.

[Sleep and wake disorders in epilepsy]

OBJECTIVE

To summarize published data on the prevalence, characteristics and diagnostic criteria of sleep disorders in epilepsy.

MATERIAL AND METHODS

A search of published articles was performed in Medline (Pubmed), Scopus, Web of Science and e-library databases.

RESULTS

Epidemiologic, clinical and diagnostic aspects of excessive daytime sleepiness, obstructive sleep apnea and central apnea, restless leg syndrome and parasomnias related to slow-wave and REM-sleep in patients with epilepsy were analyzed.

CONCLUSIONS

Further studies are needed to gain an insight into the complex associations of sleep disorders in epilepsy to optimize diagnostic and treatment approaches and to improve the quality of life in that patient population.

Standard procedures for the diagnostic pathway of sleep-related epilepsies and comorbid sleep disorders: A European Academy of Neurology, European Sleep Research Society and International League against Epilepsy-Europe consensus review

BACKGROUND

Some epilepsy syndromes (sleep-related epilepsies [SRE]) have a strong link with sleep. Comorbid sleep disorders are common in patients with SRE and can exert a negative impact on seizure control and quality of life.

PURPOSES

To define the standard procedures for the diagnostic pathway of patients with possible SRE (scenario 1) and the general management of patients with SRE and comorbidity with sleep disorders (scenario 2).

METHODS

The project was conducted under the auspices of the European Academy of Neurology (EAN), the European Sleep Research Society (ESRS) and the International League against Epilepsy (ILAE) Europe. The framework of the document entailed the following phases: conception of the clinical scenarios; literature review; statements regarding the standard procedures. For literature search a step-wise approach starting from systematic reviews to primary studies was applied. Published studies were identified from the National Library of Medicine's MEDLINE database and Cochrane Library.

RESULTS

Scenario 1: despite a low quality of evidence, recommendations on anamnestic evaluation, tools for capturing the event at home or in the laboratory are provided for specific SRE. Scenario 2: Early diagnosis and treatment of sleep disorders (especially respiratory disorders) in patients with SRE are likely to be beneficial for seizures control.

CONCLUSIONS

Definitive procedures for evaluating patients with SRE are lacking. We provide advice that could be of help for standardising and improving the diagnostic approach of specific SRE. The importance of identifying and treating specific sleep disorders for the management and outcome of patients with SRE is underlined.

Standard procedures for the diagnostic pathway of sleep-related epilepsies and comorbid sleep disorders: an EAN, ESRS and ILAE-Europe consensus review

BACKGROUND AND PURPOSE

Some epilepsy syndromes (sleep-related epilepsies, SREs) have a strong link with sleep. Comorbid sleep disorders are common in patients with SRE and can exert a negative impact on seizure control and quality of life. Our purpose was to define the standard procedures for the diagnostic pathway of patients with possible SRE (scenario 1) and the general management of patients with SRE and comorbidity with sleep disorders (scenario 2).

METHODS

The project was conducted under the auspices of the European Academy of Neurology, the European Sleep Research Society and the International League Against Epilepsy Europe. The framework entailed the following phases: conception of the clinical scenarios; literature review; statements regarding the standard procedures. For the literature search a stepwise approach starting from systematic reviews to primary studies was applied. Published studies were identified from the National Library of Medicine's MEDLINE database and Cochrane Library.

RESULTS

Scenario 1: Despite a low quality of evidence, recommendations on anamnestic evaluation and tools for capturing the event at home or in the laboratory are provided for specific SREs. Scenario 2: Early diagnosis and treatment of sleep disorders (especially respiratory disorders) in patients with SRE are likely to be beneficial for seizure control.

CONCLUSIONS

Definitive procedures for evaluating patients with SRE are lacking. Advice is provided that could be of help for standardizing and improving the diagnostic approach of specific SREs. The importance of identifying and treating specific sleep disorders for the management and outcome of patients with SRE is underlined.

Parasomnias, sleep-related movement disorders and physiological sleep variants in focal epilepsy: A polysomnographic study

PURPOSE

The link existing between epilepsy and sleep is widely recognized. However, little is known about the prevalence and the clinical consequences of the comorbidity between focal epilepsy and sleep disorders, especially those sleep phenomena classified as isolated symptoms or normal variants. Objective of the study was to evaluate the frequency of sleep disorders and physiological sleep variants in a group of adult patients with focal epilepsy as compared to healthy controls by means of nocturnal polysomnography.

METHODS

We performed a retrospective observational study in the Neurological Clinic of the University of Catania in adult patients with a diagnosis of focal epilepsy and in a group of control subjects. All subjects underwent an overnight polysomnography. The following sleep disorders were considered: NREM-related parasomnias; REM-related parasomnias; sleep-related movement disorders; isolated symptoms or normal variants.

RESULTS

100 patients [mean age 30.3 ± 14.7 years, 40 men] and 62 controls [mean age 36.4 ± 15.9, 20 men] were studied. A significant higher percentage of sleep disorders was recorded in patients as compared to controls (73 % vs 48.4 %; p = 0.002). In particular, we found a higher frequency of periodic limb movements (PLM) (20 % vs 4.8 %; p = 0.007), bruxism (20 % vs 4.8 %; p = 0.007) and neck myoclonus (22 % vs 4.8 %; p = 0.003). Moreover, alternating limb muscle activation was associated with sleep-related hypermotor epilepsy (OR = 7.9; p = 0.01).

CONCLUSION

Sleep disorders and physiological sleep variants are common in adult patients with focal epilepsy.

Seizure forecasting and cyclic control of seizures

Epilepsy is a unique neurologic condition characterized by recurrent seizures, where causes, underlying biomarkers, triggers, and patterns differ across individuals. The unpredictability of seizures can heighten fear and anxiety in people with epilepsy, making it difficult to take part in day-to-day activities. Epilepsy researchers have prioritized developing seizure prediction algorithms to combat episodic seizures for decades, but the utility and effectiveness of prediction algorithms has not been investigated thoroughly in clinical settings. In contrast, seizure forecasts, which theoretically provide the probability of a seizure at any time (as opposed to predicting the next seizure occurrence), may be more feasible. Many advances have been made over the past decade in the field of seizure forecasting, including improvements in algorithms as a result of machine learning and exploration of non-EEG-based measures of seizure susceptibility, such as physiological biomarkers, behavioral changes, environmental drivers, and cyclic seizure patterns. For example, recent work investigating periodicities in individual seizure patterns has determined that more than 90% of people have circadian rhythms in their seizures, and many also experience multiday, weekly, or longer cycles. Other potential indicators of seizure susceptibility include stress levels, heart rate, and sleep quality, all of which have the potential to be captured noninvasively over long time scales. There are many possible applications of a seizure-forecasting device, including improving quality of life for people with epilepsy, guiding treatment plans and medication titration, optimizing presurgical monitoring, and focusing scientific research. To realize this potential, it is vital to better understand the user requirements of a seizure-forecasting device, continue to advance forecasting algorithms, and design clear guidelines for prospective clinical trials of seizure forecasting.

Sex differences in factors associated with daytime sleepiness and insomnia symptoms in persons with epilepsy

Clinical factors associated with daytime sleepiness and insomnia in persons with epilepsy (PWE) were examined in this cross-sectional study of 126 participants (men, 50.8%). Excessive daytime sleepiness (EDS; score of ≥11 on the Epworth Sleepiness Scale (ESS)) was noted in 17.5% of participants (mean score, 6.1 ± 4.2), and moderate-to-severe insomnia (Insomnia Severity Index (ISI) scores of ≥15) was noted in 20.6% (mean score, 7.8 ± 6.4). Linear regression analyses revealed that ESS scores were independently associated with obstructive sleep apnea (OSA; snoring, tiredness, observed apnea, high blood pressure, body mass index, age, neck circumference, and gender (STOP-Bang) score of ≥3), an antiepileptic drug (AED) load of >3, depression (Patient Health Questionnaire-9 (PHQ-9) score of ≥10), female sex, and nocturnal seizures. Insomnia Severity Indices were independently associated with depression and anxiety (Generalized Anxiety Disorder-7 (GAD-7) score of ≥7). Notably, significant sex differences were found. Epworth Sleepiness Scale scores were associated with OSA in men but were associated with depression in women. In addition, anxiety was associated with insomnia in women only. Overall, OSA and depression were the most important significant clinical factors associated with daytime sleepiness and insomnia, respectively. However, there were sex differences for the associations between individual factors and sleep disturbances.

Serotonin and sudden unexpected death in epilepsy

Epilepsy is a highly prevalent disease characterized by recurrent, spontaneous seizures. Approximately one-third of epilepsy patients will not achieve seizure freedom with medical management and become refractory to conventional treatments. These patients are at greatest risk for sudden unexpected death in epilepsy (SUDEP). The exact etiology of SUDEP is unknown, but a combination of respiratory, cardiac, neuronal electrographic dysfunction, and arousal impairment is thought to underlie SUDEP. Serotonin (5-HT) is involved in regulation of breathing, sleep/wake states, arousal, and seizure modulation and has been implicated in the pathophysiology of SUDEP. This review explores the current state of understanding of the relationship between 5-HT, epilepsy, and respiratory and autonomic control processes relevant to SUDEP in epilepsy patients and in animal models.

Cortical functional connectivity indexes arousal state during sleep and anesthesia

Disruption of cortical connectivity likely contributes to loss of consciousness (LOC) during both sleep and general anesthesia, but the degree of overlap in the underlying mechanisms is unclear. Both sleep and anesthesia comprise states of varying levels of arousal and consciousness, including states of largely maintained conscious experience (sleep: N1, REM; anesthesia: sedated but responsive) as well as states of substantially reduced conscious experience (sleep: N2/N3; anesthesia: unresponsive). Here, we tested the hypotheses that (1) cortical connectivity will exhibit clear changes when transitioning into states of reduced consciousness, and (2) these changes will be similar for arousal states of comparable levels of consciousness during sleep and anesthesia. Using intracranial recordings from five adult neurosurgical patients, we compared resting state cortical functional connectivity (as measured by weighted phase lag index, wPLI) in the same subjects across arousal states during natural sleep [wake (WS), N1, N2, N3, REM] and propofol anesthesia [pre-drug wake (WA), sedated/responsive (S), and unresponsive (U)]. Analysis of alpha-band connectivity indicated a transition boundary distinguishing states of maintained and reduced conscious experience in both sleep and anesthesia. In wake states WS and WA, alpha-band wPLI within the temporal lobe was dominant. This pattern was largely unchanged in N1, REM, and S. Transitions into states of reduced consciousness N2, N3, and U were characterized by dramatic changes in connectivity, with dominant connections shifting to prefrontal cortex. Secondary analyses indicated similarities in reorganization of cortical connectivity in sleep and anesthesia. Shifts from temporal to frontal cortical connectivity may reflect impaired sensory processing in states of reduced consciousness. The data indicate that functional connectivity can serve as a biomarker of arousal state and suggest common mechanisms of LOC in sleep and anesthesia.

Spatial distribution of interictal spikes fluctuates over time and localizes seizure onset

The location of interictal spikes is used to aid surgical planning in patients with medically refractory epilepsy; however, their spatial and temporal dynamics are poorly understood. In this study, we analysed the spatial distribution of interictal spikes over time in 20 adult and paediatric patients (12 females, mean age = 34.5 years, range = 5-58) who underwent intracranial EEG evaluation for epilepsy surgery. Interictal spikes were detected in the 24 h surrounding each seizure and spikes were clustered based on spatial location. The temporal dynamics of spike spatial distribution were calculated for each patient and the effects of sleep and seizures on these dynamics were evaluated. Finally, spike location was assessed in relation to seizure onset location. We found that spike spatial distribution fluctuated significantly over time in 14/20 patients (with a significant aggregate effect across patients, Fisher's method: P < 0.001). A median of 12 sequential hours were required to capture 80% of the variability in spike spatial distribution. Sleep and postictal state affected the spike spatial distribution in 8/20 and 4/20 patients, respectively, with a significant aggregate effect (Fisher's method: P < 0.001 for each). There was no evidence of pre-ictal change in the spike spatial distribution for any patient or in aggregate (Fisher's method: P = 0.99). The electrode with the highest spike frequency and the electrode with the largest area of downstream spike propagation both localized the seizure onset zone better than predicted by chance (Wilcoxon signed-rank test: P = 0.005 and P = 0.002, respectively). In conclusion, spikes localize seizure onset. However, temporal fluctuations in spike spatial distribution, particularly in relation to sleep and post-ictal state, can confound localization. An adequate duration of intracranial recording-ideally at least 12 sequential hours-capturing both sleep and wakefulness should be obtained to sufficiently sample the interictal network.

Breakthrough spikes in rapid eye movement sleep from the epilepsy monitoring unit are associated with peak seizure frequency

Study Objectives

Rapid eye movement sleep (REM) usually suppresses interictal epileptiform discharges (IED) and seizures. However, breakthrough IEDs in REM sometimes continue. We aimed to determine if the amount of IED and seizures in REM, or REM duration, is associated with clinical trajectories.

Methods

Continuous electroencephalogram (EEG) recordings from the epilepsy monitoring unit (EMU) were clipped to at least 3 h of concatenated salient findings per day including all identified REM. Concatenated EEG files were analyzed for nightly REM duration and the “REM spike burden” (RSB), defined as the proportion of REM occupied by IED or seizures. Patient charts were reviewed for clinical data, including patient-reported peak seizure frequency. Logistic and linear regressions were performed, as appropriate, to explore associations between two explanatory measures (duration of REM and RSB) and six indicators of seizure activity (clinical trajectory outcomes).

Results

The median duration of REM sleep was 43.3 (IQR 20.9–73.2) min per patient per night. 59/63 (93.7%) patients achieved REM during EMU admission. 39/59 (66.1%) patients had breakthrough IEDs or seizures in REM with the median RSB at 0.7% (IQR 0%–8.4%). Every 1% increase in RSB was associated with 1.69 (95% CI = 0.47–2.92) more seizures per month during the peak seizure period of one’s epilepsy (p = 0.007).

Conclusions

Increased epileptiform activity during REM is associated with increased peak seizure frequency, suggesting an overall poorer epilepsy trajectory. Our findings suggest that RSB in the EMU is a useful biomarker to help guide about what to expect over the course of one’s epilepsy.

Ear-EEG-based sleep scoring in epilepsy: A comparison with scalp-EEG

Ear-EEG is a wearable electroencephalogram-recording device. It relies on recording electrodes that are nested within a custom-fitted earpiece in the external ear canal. The concept has previously been tested for seizure detection in epileptic patients and for sleep recordings in a healthy population. This study is the first to examine the use of ear-EEG recordings for sleep staging in patients with epilepsy, comparing it with standard recordings from scalp-EEG. We use individuals with epilepsy because of their multiple sleep disturbances, and their complex relationship between seizures and sleep, which make this group very likely to benefit from wearable electroencephalogram devices for sleep if it were introduced in the clinic. The accuracy of the ear-EEG against that of the scalp-EEG is compared for sleep staging, and we evaluate features of sleep architecture in individuals with epilepsy. A mean kappa value of 0.74 is found for the agreement between hypnograms derived from ear-EEG and scalp-EEG. Furthermore, it was discovered that sleep stage transition frequency could be contributing to the kappa variation. These findings are related to other ear-recording systems in the literature, and the potentials and future obstacles of the device are discussed.

Sleepwalking and Sleep Paralysis: Prevalence in Colombian Families With Genetic Generalized Epilepsy

BACKGROUND

Sleep deprivation commonly increases seizure frequency in patients with genetic generalized epilepsy, though it is unknown whether there is an increased prevalence of sleepwalking or sleep paralysis in genetic generalized epilepsy patients. Establishing this could provide insights into the bio-mechanisms or genetic architecture of both disorders. The aim of this study was to determine the prevalence of sleepwalking and sleep paralysis in a cohort of patients with genetic generalized epilepsy and their relatives in extended families.

METHODS

A structured interview based on International League Against Epilepsy (ILAE) and International Classification of Sleep Disorders (ICSD-3) criteria was applied to 67 index cases and their relatives to determine genetic generalized epilepsy subtypes and assess the occurrence of sleepwalking or sleep paralysis. Bivariate analysis was performed using chi-square and Fisher exact tests.

RESULTS

The prevalence of sleepwalking and sleep paralysis was 15.3% (95% confidence interval 12.1-18.9) and 11.7% (95% confidence interval 8.7-15.3), respectively. Unusually, no sleepwalkers were found among individuals displaying epilepsy with generalized tonic-clonic seizures. Approximately a quarter of the patients had either parasomnia or genetic generalized epilepsy. Over half the genetic generalized epilepsy families had at least 1 individual with sleepwalking, and more than 40% of the families had one individual with sleep paralysis.

CONCLUSION

The prevalence of sleepwalking or sleep paralysis is reported for individuals with genetic generalized epilepsy and their relatives. The co-existence of either parasomnia in the genetic generalized epilepsy patients and the co-aggregation within their families let suggest that shared heritability and pathophysiological mechanisms exist between these disorders. We hypothesize that sleepwalking/sleep paralysis and genetic generalized epilepsy could be variable expression of genes in shared pathways.

Electroencephalogram abnormalities in patients with NREM parasomnias

OBJECTIVE

Electroencephalographic (EEG) changes in patients with NREM parasomnias (NRP) occur in sleep architecture as changes in slow wave sleep or cyclic pattern, which are not considered abnormal. However, abnormalities in EEG in these patients have recently been reported, indicating that EEG patterns in NRPs are not definitive. Moreover, most of the polysomnography (PSG) findings in NRP patients were reported in the adult population requiring data from pediatric population to avoid bias in conclusion.

METHODS

In sum, 39 patients with a NRP were undergone comprehensive assessments including a PSG with additional EEG montages. EEG recordings were evaluated in patients without a history of epilepsy and further compared between pediatric and adult patients.

RESULTS

Twenty-three (59%) of the patients were pediatric and 77% were male. The mean age was 18.4 (±13.1) years. Of the patients, 19 (49%) had somnambulism, 13 (33%) had confusional arousal and seven (18%) had sleep terrors. Macrostructure of sleep detected by PSG was normal in all patients. After excluding 11 (28%) patients with a positive history of epilepsy, seven (25%) of 28 showed EEG abnormalities within K-complexes in NREM-II stage, six of whom were pediatric patients compared to only one adult (p < 0.05).

CONCLUSION

This study showed that patients with NRP may display EEG abnormalities in NREM-II stage. These abnormalities were more frequent in pediatric patients compared to adults. In NRP patients, utmost care should be taken in EEG evaluations to prevent false diagnosis of epilepsy.

The Use of Caffeine by People with Epilepsy: the Myths and the Evidence

PURPOSE OF REVIEW

Caffeine is the most widely consumed central nervous stimulant. For people with epilepsy, it is often unclear whether drinking coffee carries a risk of triggering seizures.

RECENT FINDINGS

The relationship between caffeine, seizures, epilepsy, and anti-seizure drugs is not fully understood. Clinical studies are scarce. In animal models, caffeine can increase seizure susceptibility but can also protect from seizures. Effects seem dose-dependent and are influenced by the duration of intake and the developmental stage at which caffeine exposure started. Caffeine reduces the efficacy of several anti-seizure medications, especially topiramate. It is unclear how these findings, mainly from animal studies, can be translated to the clinical condition. At present, there is no evidence to advise people with epilepsy against the use or overuse of caffeine. Until clinical studies suggest otherwise, caffeine intake should be considered as a factor in achieving and maintaining seizure control in epilepsy.

Chronobiology of limbic seizures: Potential mechanisms and prospects of chronotherapy for mesial temporal lobe epilepsy

Mesial Temporal Lobe Epilepsy (mTLE) characterized by progressive development of complex partial seizures originating from the hippocampus is the most prevalent and refractory type of epilepsy. One of the remarkable features of mTLE is the rhythmic pattern of occurrence of spontaneous seizures, implying a dependence on the endogenous clock system for seizure threshold. Conversely, circadian rhythms are affected by epilepsy too. Comprehending how the circadian system and seizures interact with each other is essential for understanding the pathophysiology of epilepsy as well as for developing innovative therapies that are efficacious for better seizure control. In this review, we confer how the temporal dysregulation of the circadian clock in the hippocampus combined with multiple uncoupled oscillators could lead to periodic seizure occurrences and comorbidities. Unraveling these associations with additional research would help in developing chronotherapy for mTLE, based on the chronobiology of spontaneous seizures. Notably, differential dosing of antiepileptic drugs over the circadian period and/or strategies that resynchronize biological rhythms may substantially improve the management of seizures in mTLE patients.

Electronic health record cue identifies epilepsy patients at risk for obstructive sleep apnea

Background

Prior studies have reported that patients with epilepsy have a higher prevalence of obstructive sleep apnea (OSA) that contributes to poor seizure control. Detection and treatment of OSA can improve seizure control in some patients with epilepsy. In this study, we sought to develop, implement, and evaluate the effectiveness of an electronic health record (EHR) alert to screen for OSA in patients with epilepsy.

Methods

A 3-month retrospective chart review was conducted of all patients with epilepsy >18 years of age who were evaluated in our epilepsy clinics prior to the intervention. An assessment for obstructive sleep apnea (AOSA) consisting of 12 recognized risk factors for OSA was subsequently developed and embedded in the EHR. The AOSA was utilized for a 3-month period. Patients identified with 2 or more risk factors were referred for polysomnography. A comparison was made to determine if there was a difference in the number of patients at risk for OSA detected and referred for polysomnography with and without an EHR alert to screen for OSA.

Results

There was a significant increase in OSA patient recognition. Prior to the EHR alert, 25/346 (7.23%) patients with epilepsy were referred for a polysomnography. Postintervention, 405/414 patients were screened using an EHR alert for AOSA and 134/405 (33.1%) were referred for polysomnography (p < 0.001).

Conclusion

An intervention with AOSA cued in the EHR demonstrated markedly improved identification of epilepsy patients at risk for OSA and referral for polysomnography.

Neuroendocrine aspects of improving sleep in epilepsy

Sleep plays an intricate role in epilepsy and can affect the frequency and occurrence of seizures. With nearly 35% of U.S. adults failing to obtain the recommended 7 h of sleep every night, understanding the complex relationship between sleep and epilepsy is of utmost relevance. Sleep deprivation is a common trigger of seizures in many persons with epilepsy and sleep patterns play a role in the occurrence of seizures. Some patients have their first seizure or repeated seizures after an "all-nighter" at college or after a long period of chronic sleep deprivation. The strength of the relationship between sleep and seizures varies between patients, but improving sleep and optimizing seizure control can have significant positive effects on the quality of life for all these patients. Research has shown that the changes in the brain's electrical and hormonal activity occurring during normal sleep-wake cycles can be linked to both sleep and seizure patterns. Many questions remain to be answered about sleep and epilepsy. How can sleep deprivation trigger an epileptic seizure? How do circadian and hormonal changes influence sleep pattern and seizure occurrence? Can hormones or sleeping pills help with sleep in epilepsy? In this article we discuss these and many other questions on sleep in epilepsy, with an emphasis on sleep architecture, hormone changes, mechanistic factors, and possible prevention strategies.

Gauging seizure risk

The current paradigm for treatment of epilepsy begins with trials of antiepileptic drugs, followed by evaluation for resective brain surgery in drug-resistant patients. If surgery is not possible or fails to control seizures, some patients benefit from implanted neurostimulation devices. In addition to their therapeutic benefit, some of these devices have diagnostic capability enabling recordings of brain activity with unprecedented chronicity. Two recent studies using different devices for chronic EEG (i.e., over months to years) yielded convergent findings of daily and multiday cycles of brain activity that help explain seizure timing. Knowledge of these patient-specific cycles can be leveraged to gauge and forecast seizure risk, empowering patients to adopt risk-stratified treatment strategies and behavioral modifications. We review evidence that epilepsy is a cyclical disorder, and we argue that implanted monitoring devices should be offered earlier in the treatment paradigm. Chronic EEG would allow pharmacologic treatments tailored to days of high seizure risk-here termed chronotherapy-and would help characterize long timescale seizure dynamics to improve subsequent surgical planning. Coupled with neuromodulation, the proposed approach could improve quality of life for patients and decrease the number ultimately requiring resective surgery. We outline challenges for chronic monitoring and seizure forecasting that demand close collaboration among engineers, neurosurgeons, and neurologists.

Sleep is associated with reduction of epileptiform discharges in benign adult familial myoclonus epilepsy

To clarify the effects of sleep on cortical irritability in benign adult familial myoclonus epilepsy (BAFME), we retrospectively compared epileptiform discharges of electroencephalographies (EEGs) between awake and sleep periods in 5 patients (mean age: 49.6 ± 20.3 years). We also analyzed polysomnography (PSG) of 1 patient. Epileptiform discharges were significantly more frequent during the awake period (1.3 ± 1.2/min) than those during light sleep stages (0.02 ± 0.04/min) (P < 0.05). Regarding PSG analysis, epileptiform discharges were also reduced during all sleep stages compared to those during awake periods. Our study suggests a relative reduction in cortical irritability during sleep in BAFME.

Sleep Related Epilepsy and Pharmacotherapy: An Insight

In the last several decades, sleep-related epilepsy has drawn considerable attention among epileptologists and neuroscientists in the interest of new paradigms of the disease etiology, pathogenesis and management. Sleep-related epilepsy is nocturnal seizures that manifest solely during the sleep state. Sleep comprises two distinct stages i.e., non-rapid eye movement (NREM) and rapid eye movement (REM) that alternate every 90 min with NREM preceding REM. Current findings indicate that the sleep-related epilepsy manifests predominantly during the synchronized stages of sleep; NREM over REM stage. Sleep related hypermotor epilepsy (SHE), benign partial epilepsy with centrotemporal spikes or benign rolandic epilepsy (BECTS), and Panayiotopoulos Syndrome (PS) are three of the most frequently implicated epilepsies occurring during the sleep state. Although some familial types are described, others are seemingly sporadic occurrences. In the present review, we aim to discuss the predominance of sleep-related epilepsy during NREM, established familial links to the pathogenesis of SHE, BECTS and PS, and highlight the present available pharmacotherapy options.