High incidence of obstructive sleep apnea syndrome in patients with late-onset 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.

Sleep and epilepsy: A clinical and pathophysiological overview

The interaction between sleep and epilepsy is complex. A better understanding of the mechanisms linking sleep and epilepsy appears increasingly important as it may improve diagnosis and therapeutic strategies in patients with epilepsy. In this narrative review, we aim to (i) provide an overview of the physiological and pathophysiological processes linking sleep and epilepsy; (ii) present common sleep disorders in patients with epilepsy; (iii) discuss how sleep and sleep disorders should be considered in new therapeutic approaches to epilepsy such as neurostimulation; and (iv) present the overall nocturnal manifestations and differential diagnosis between epileptic seizures and parasomnia.

Obstructive sleep apnea induced bilateral tonic- clonic seizure of unknown origin: A case series of a novel association

Background

Obstructive sleep apnea is a highly prevalent disorder, characterized by recurrent events of upper airway obstruction during sleep and associated with recurrent cycles of desaturation and re-oxygenation, sympathetic hyperactivity, and intra-thoracic pressure fluctuations, resulting in fragmentation of sleep and subsequent daytime fatigue with excessive sleepiness. Obstructive sleep apnea-induced bilateral tonic-clonic seizures are unheard of. We aimed to report 3 patients with previously undiagnosed obstructive sleep apnea who presented to the emergency department with new onset bilateral tonic-clonic seizure without any evidential neurological or metabolic cause.

Methods

Patient data were obtained from medical records from the Department of Internal Medicine, IPGMER and SSKM Hospital, Kolkata, and Belle Vue Clinic, Kolkata, India.

Results

Three male patients (67, 58, and 44 years old) presented with bilateral tonic-clonic seizure disorder without any underlying cause of seizures after rigorous investigations except for moderate to severe obstructive sleep apnea on polysomnography. All 2 patients were seizure-free after being treated with levetiracetam, chronic continuous positive airway pressure therapy in 2, and only continuous positive airway pressure in the other. The patients remained seizure-free on continuous positive airway pressure, even when levetiracetam was withdrawn, suggesting obstructive sleep apnea's causality in their new-onset acute seizures.

Conclusion

Although further investigation is required to clarify this association, underlying obstructive sleep apnea should be ruled out in patients with a first-ever bilateral tonic-clonic seizure. Whether or not continuous positive airway pressure alone could effectively treat hypoxia and deranged cortical excitability, which may lead to seizures in cases with longstanding obstructive sleep apnea, is yet to be explored.

Sleep Disturbances in Neurological Disease: A Target for Intervention

Sleep is a biological function required for neurological and general health, but a significant and under-recognized proportion of the population has disturbed sleep. Here, we briefly overview the biology of sleep, sleep requirements over the lifespan, and common sleep disorders. We then turn our attention to five neurological diseases that significantly contribute to global disease burden and neurology practice makeup: epilepsy, headache, ischemic stroke, Parkinson's disease, and Alzheimer's disease. For each disease, we review evidence that sleep disturbances contribute to disease risk and severity and discuss existing data that addressing sleep disturbances may have disease-modifying effects. We provide recommendations derived from the literature and existing clinical guidelines to facilitate the evaluation and management of sleep disturbances within the context of each neurological disease. Finally, we synthesize identified needs and commonalities into future directions for the field and practical sleep-related recommendations for physicians caring for patients at risk for or currently suffering from neurological disease.

Identifying obstructive sleep apnea in patients with epilepsy: A cross-sectional multicenter study

OBJECTIVE

Several screening questionnaires for obstructive sleep apnea (OSA) have been introduced. No study has compared the performance of different questionnaire in the same patients with epilepsy. Herein, we compare the performance characteristics of four common questionnaires for assessing the probability of OSA in patients with epilepsy.

METHODS

This cross-sectional multicenter study was conducted among adult epilepsy patients attending neurology and general medical clinics in Thailand. Before performing full polysomnography (PSG), all participants completed the STOP-BANG, STOP-BAG, SA-SDQ, and NoSAS questionnaires. OSA was defined by apnea/ hypopnea index (AHI) criteria of AHI: ≥ 5, ≥ 15, and ≥ 30. Discriminatory ability was assessed by area under the receiver operating characteristics (ROC) curve (AUC) and likelihood ratio. To improve discriminative ability, we created 3 ranges of the score to predict lower, middle, and higher probability of OSA as defined by each diagnostic criterion.

RESULTS

A total 166 patients with epilepsy were included. OSA prevalence was 38%. Overall, NoSAS had higher AUC at all AHI criteria but not significantly higher than that of other scales. Using prediction cut-points for NoSAS of ≥ 4 and ≥ 8 to predict OSA defined by AHI ≥ 5, the likelihood ratios for the 3 ranges were 0.37, 2.22 and 9.81 respectively.

CONCLUSION

Among the 4 scales, the 2-cut-point NoSAS score had the highest discriminatory ability at each AHI cutoff.

Expert Opinion: Managing sleep disturbances in people with epilepsy

Poor sleep and daytime sleepiness are common in people with epilepsy. Sleep disorders can disrupt seizure control and in turn sleep and vigilance problems can be exacerbated by seizures and by antiepileptic treatments. Nevertheless, these aspects are frequently overlooked in clinical practice and a clear agreement on the evidence-based guidelines for managing common sleep disorders in people with epilepsy is lacking. Recently, recommendations to standardize the diagnostic pathway for evaluating patients with sleep-related epilepsies and comorbid sleep disorders have been presented. To build on these, we adopted the Delphi method to establish a consensus within a group of experts and we provide practical recommendations for identifying and managing poor night-time sleep and daytime sleepiness in people with epilepsy. We recommend that a comprehensive clinical history of sleep habits and sleep hygiene should be always obtained from all people with epilepsy and their bed partners. A psychoeducational approach to inform patients about habits or practices that may negatively influence their sleep or their vigilance levels should be used, and strategies for avoiding these should be applied. In case of a suspected comorbid sleep disorder an appropriate diagnostic investigation should be performed. Moreover, the possible presence of sleep fragmentation induced by sleep-related seizures should be ruled out. Finally, the dose and timing of antiepileptic medications and other co-medications should be optimized to improve nocturnal sleep and avoid daytime sedation.

Regulation of microRNA Expression in Sleep Disorders in Patients with Epilepsy

The effects of epilepsy on sleep and the activating effects of sleep on seizures are well documented in the literature. To date, many sleep-related and awake-associated epilepsy syndromes have been described. The relationship between sleep and epilepsy has led to the recognition of polysomnographic testing as an important diagnostic tool in the diagnosis of epilepsy. The authors analyzed the available medical database in search of other markers that assess correlations between epilepsy and sleep. Studies pointing to microRNAs, whose abnormal expression may be common to epilepsy and sleep disorders, are promising. In recent years, the role of microRNAs in the pathogenesis of epilepsy and sleep disorders has been increasingly emphasized. MicroRNAs are a family of single-stranded, non-coding, endogenous regulatory molecules formed from double-stranded precursors. They are typically composed of 21–23 nucleotides, and their main role involves post-transcriptional downregulation of expression of numerous genes. Learning more about the role of microRNAs in the pathogenesis of sleep disorder epilepsy may result in its use as a biomarker in these disorders and application in therapy.

Bidirectional relationships of sleep and epilepsy in adults with epilepsy

This targeted review addresses the best accepted and most intriguing recent observations on the complex relationships between sleep and epilepsy. Ten to 15% of all epilepsies are sleep-related. Included in these is sleep-related hypermotor epilepsy, renamed from nocturnal frontal lobe epilepsy by a 2016 consensus conference since 30% of cases are extra-frontal, seizures are related to sleep rather than clock time, and the predominant semiology is hypermotor. Stereo-EEG is providing crucial insights into network activation in sleep-related epilepsies and definition of the epileptogenic zone. Pathologic high-frequency oscillations, a promising biomarker for identifying the epileptogenic zone, are most frequent in NREM sleep, lowest in wakefulness and REM sleep, similar to interictal epileptiform discharges (IEDs). Most sleep-related seizures are followed by awakening or arousal and IEDs cause arousals and increase after arousals, likely contributing to sleep/wake complaints. Sleep/wake disorders are 2-3 times more common in adults with epilepsy than the general population; these comorbidities are associated with poorer quality of life and may impact seizure control. Treatment of sleep apnea reduces seizures in many cases. An emerging area of research is in circadian biology and epilepsy. Over 90% of people with epilepsy have seizures with circadian periodicity, in part related to sleep itself, and the majority of SUDEP cases occur in sleep. Recognizing these bidirectional relationships is important for patient and caregiver education and counseling and optimizing epilepsy outcomes.

Psychosis rarely occurs in patients with late-onset focal epilepsy

AIMS

We examined psychosis occurrence in patients with late-onset focal epilepsy.

SUBJECTS AND METHODS

Case records of consecutive patients with focal epilepsy without central nervous system (CNS) disease (n = 873) were retrospectively examined, with gender, age at epilepsy onset, duration of epilepsy, epilepsy type (temporal or extratemporal), and age at the initial examination used as clinical and demographic variables. Patients with onset ≤49 years old (control) were compared with those with late-onset.

RESULTS

In the control group (n = 775), 38 had a history of psychosis, while none in the late-onset group (n = 98) reported that (p = 0.016). Psychosis was only interictal in 32 and predominantly postictal in 6, while 2 patients showed both interictal and postictal psychosis. Duration of illness (p = 0.000001) and temporal lobe epilepsy (p = 0.000343) were significant determinants associated with psychosis. Gender (p = 0.210) and age at examination (p = 0.084) were found to be not contributory to psychosis.

DISCUSSION

The prevalence for a history of psychosis in the present cohort (2.5%) agrees well with that noted in previous studies, and duration of illness proved to be the most powerful determining factor leading to that. A keen awareness of unrecognized underlying CNS or metabolic disease is important when psychosis appears in patients with nonlesional late-onset epilepsy, which should lead to an in-depth investigation of possible underlying and still uncovered CNS disease.

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.

Association of obstructive sleep apnea and cerebral small vessel disease: a systematic review and meta-analysis

Study Objectives

The objective of the present study was to investigate the association between obstructive sleep apnea (OSA) and the presence of various neuroimaging marker of cerebral small vessel disease (CSVD).

Methods

We systematically searched PubMed, Embase, Web of Science, Scopus, and Cochrane library (from inception to May 2019) for studies evaluating the association between OSA and CSVD, which included white matter hyperintensities (WMH), silent brain infarction (SBI), cerebral microbleeds (CMBs), and perivascular spaces (PVS). Pooled odds ratios (ORs) with 95% confidence interval (CIs) were estimated using random-effects meta-analysis.

Results

After screening 7290 publications, 20 studies were finally included involving 6036 subjects. The sample size ranged from 27 to 1763 (median 158, interquartile range: 67–393). The meta-analysis showed that moderate to severe OSA was positively associated with WMH (13 studies, n = 4412, OR = 2.23, 95% CI = 1.53 to 3.25, I2 = 80.3%) and SBI (12 studies, n = 3353, OR 1.54, 95% CI = 1.06 to 2.23, I2 = 52%). There was no association with CMBs (three studies, n = 342, OR = 2.17, 95% CI = 0.61 to 7.73, I2 = 60.2%) or PVS (two studies, n = 267, OR = 1.56, 95% CI = 0.28 to 8.57, I2 = 69.5%). There was no relationship between mild OSA and CSVD.

Conclusion

Current evidence suggests that moderate to severe sleep apnea is positively related to WMH and SBI, but not CMBs or PVS, which suggests that OSA may contribute to the pathogenesis of CSVD. Further large cohort studies should be prioritized to confirm the findings.

Late-onset unexplained epilepsy: What are we missing?

With the aging of the US population, the incidence of epilepsy will increase, with 25 to 50% of new cases with no identifiable etiology diagnosed as late-onset unexplained epilepsy (LOUE). In the current targeted review, we discuss the possible role of cerebral small vessel ischemic disease, accumulation of amyloidβ and hyperphosphorylated tau, and sleep apnea as potential pathophysiologic mechanisms explaining LOUE. We highlight the impact of these processes on cognition and avenues for diagnosis and treatment.

Sleep-disordered breathing among patients admitted for inpatient video-EEG monitoring

Objective

To examine the prevalence and risk factors of sleep-disordered breathing (SDB) in individuals with epilepsy and psychogenic nonepileptic seizures (PNES).

Methods

We conducted a cross-sectional study of consecutive patients admitted for inpatient video-EEG monitoring at The Royal Melbourne Hospital, Australia, between December 1, 2011, and July 31, 2017. Participants underwent routine clinical investigations during their monitoring period including polysomnography, neurocognitive testing, and screening instruments of daytime somnolence, sleep quality, and quality of life.

Results

Our study population consisted of 370 participants who received a diagnosis of epilepsy (n = 255), PNES (n = 93), or both disorders (n = 22). Moderate to severe SDB (defined by an apnea-hypopnea index ≥15) was observed in 26.5% (98/370) of individuals, and did not differ across subgroups: epilepsy 26.3% (67/255), PNES 29.0% (27/93), or both disorders 18.2% (4/22; p = 0.610). Following adjustment for confounders, pathologic daytime sleepiness predicted moderate to severe SDB in epilepsy (odds ratio [OR] 10.35, 95% confidence interval [CI] 2.09–51.39; p = 0.004). In multivariable analysis, independent predictors for moderate to severe SDB in epilepsy were older age (OR 1.07, 95% CI 1.04–1.10; p < 0.001) and higher body mass index (OR 1.06, 95% CI 1.01–1.11; p = 0.029), and in PNES older age (OR 1.10, 95% CI 1.03–1.16; p = 0.002).

Conclusion

Polysomnography during inpatient video-EEG monitoring identified a substantial number of patients with undiagnosed SDB. This was remarkable in the subgroup with PNES, who were often female and obese. Identification of risk factors may improve management of SDB in these populations. The association with pathologic daytime sleepiness suggests that SDB may be an important contributor to these common and disabling symptoms in patients with epilepsy.

Co-morbid sleep disorders and epilepsy: A narrative review and case examples

Co-morbid sleep disorders, including sleep apnea, insomnia, restless legs syndrome, and the parasomnias, occur frequently in people with epilepsy. This article reviews the cardinal presenting symptoms and diagnostic features of each of these disorders to enable epileptologists to readily screen and identify sleep co-morbidities in their patients. It summarizes current evidence concerning the reciprocal relationship between sleep disturbances and epilepsy and available treatment options for common sleep disorders in people with epilepsy. Several illustrative cases demonstrate the practical consequences of co-morbid sleep disorders in epilepsy patients and suggest diagnostic and treatment approaches that may improve daytime functioning, alertness, quality of life, and seizure burden.

Obstructive sleep apnea and cerebral white matter change: a systematic review and meta-analysis

Obstructive sleep apnea (OSA) can cause sleep fragmentation and intermittent hypoxemia, which are linked to oxidative stress. White matter changes (WMCs) representing cerebrovascular burden and are at risk factor for oxidative ischemic injury. The current study explores the mutual relationships between OSA and WMCs. We performed a systematic review of electronic databases for clinical studies investigating OSA and WMCs. Random-effects models were used for pooled estimates calculation. A total of 22 studies were included in the meta-analysis. The results revealed a significantly higher prevalence rate of WMCs [odds ratio (OR) 2.06, 95% confidence interval (CI) 1.52-2.80, p < 0.001] and significantly higher severity of WMCs (Hedges' g = 0.23, 95% CI 0.06-0.40, p = 0.009) in the patients with OSA than in controls. Furthermore, the results revealed a significantly higher apnea-hypopnea index (Hedges' g = 0.54, 95% CI 0.31-0.78, p < 0.001) and significantly higher prevalence rate of moderate-to-severe OSA (OR 2.86, 95% CI 1.44-5.66, p = 0.003) in the patients with WMCs than in controls, however there was no significant difference in the prevalence rate of mild OSA between the patients with WMCs and controls (OR 0.71, 95% CI 0.20-2.54, p = 0.603). OSA was associated with a higher prevalence and more severe WMCs, and the patients with WMCs had an increased association with moderate-to-severe OSA. Future large-scale randomized controlled trials with a longitudinal design are essential to further evaluate treatment in patients with OSA.