REM obstructive sleep apnea: risk for adverse health outcomes and novel treatments

Rapid eye movement (REM) sleep was discovered nearly 60 years ago. This stage of sleep accounts for approximately a quarter of total sleep time in healthy adults, and it is mostly concentrated in the second half of the sleep period. The majority of research on REM sleep has focused on neurocognition. More recently, however, there has been a growing interest in understanding whether obstructive sleep apnea (OSA) during the two main stages of sleep (REM and non-REM sleep) leads to different cardiometabolic and neurocognitive risk. In this review, we discuss the growing evidence indicating that OSA during REM sleep is a prevalent disorder that is independently associated with adverse cardiovascular, metabolic, and neurocognitive outcomes. From a therapeutic standpoint, we discuss limitations of continuous positive airway pressure (CPAP) therapy given that 3 or 4 h of CPAP use from the beginning of the sleep period would leave 75% or 60% of obstructive events during REM sleep untreated. We also review potential pharmacologic approaches to treating OSA during REM sleep. Undoubtedly, further research is needed to establish best treatment strategies in order to effectively treat REM OSA. Moreover, it is critical to understand whether treatment of REM OSA will translate into better patient outcomes.

Pre- to postsleep change in psychophysiological reactivity to emotional films: Late-night REM sleep is associated with attenuated emotional processing

Rapid eye movement (REM) sleep has been postulated to facilitate emotional processing of negative stimuli. However, empirical evidence is mixed and primarily based on self-report data and picture-viewing studies. This study used a full-length aversive film to elicit intense emotion on one evening, and an emotionally neutral control film on another evening while psychophysiological and experiential responses were measured. Subsequent sleep was monitored polysomnographically, and specific film scenes were presented again on the next morning. Correlation analyses revealed that participants with longer late-night REM sleep after the aversive film showed higher increase of electrodermal reactivity and less reduction of facial corrugator muscle reactivity to negative film scenes on the next morning. This indicates that REM sleep may be associated with attenuated emotional processing of prolonged and intense emotional stimuli from pre- to postsleep.

Sleep deprivation impairs performance in the 5-choice continuous performance test: similarities between humans and mice

Several groups undergo extended periods without sleep due to working conditions or mental illness. Such sleep deprivation (SD) can deleteriously affect attentional processes and disrupt work and family functioning. Understanding the biological underpinnings of SD effects may assist in developing sleep therapies and cognitive enhancers. Utilizing cross-species tests of attentional processing in humans and rodents would aid in mechanistic studies examining SD-induced inattention. We assessed the effects of 36h of: (1) Total SD (TSD) in healthy male and female humans (n=50); and (2) REM SD (RSD) in male C57BL/6 mice (n=26) on performance in the cross-species 5-choice continuous performance test (5C-CPT). The 5C-CPT includes target trials on which subjects were required to respond and non-target trials on which subjects were required to inhibit from responding. TSD-induced effects on human psychomotor vigilance test (PVT) were also examined. Effects of SD were also examined on mice split into good and poor performance groups based on pre-deprivation scores. In the human 5C-CPT, TSD decreased hit rate and vigilance with trend-level effects on accuracy. In the PVT, TSD slowed response times and increased lapses. In the mouse 5C-CPT, RSD reduced accuracy and hit rate with trend-level effects on vigilance, primarily in good performers. In conclusion, SD induced impaired 5C-CPT performance in both humans and mice and validates the 5C-CPT as a cross-species translational task. The 5C-CPT can be used to examine mechanisms underlying SD-induced deficits in vigilance and assist in testing putative cognitive enhancers.

Seizure likelihood varies with day-to-day variations in sleep duration in patients with refractory focal epilepsy: A longitudinal electroencephalography investigation

BACKGROUND

While the effects of prolonged sleep deprivation (≥24 h) on seizure occurrence has been thoroughly explored, little is known about the effects of day-to-day variations in the duration and quality of sleep on seizure probability. A better understanding of the interaction between sleep and seizures may help to improve seizure management.

METHODS

To explore how sleep and epileptic seizures are associated, we analysed continuous intracranial electroencephalography (EEG) recordings collected from 10 patients with refractory focal epilepsy undergoing ordinary life activities between 2010 and 2012 from three clinical centres (Austin Health, The Royal Melbourne Hospital, and St Vincent's Hospital of the Melbourne University Epilepsy Group). A total of 4340 days of sleep-wake data were analysed (average 434 days per patient). EEG data were sleep scored using a semi-automated machine learning approach into wake, stages one, two, and three non-rapid eye movement sleep, and rapid eye movement sleep categories.

FINDINGS

Seizure probability changes with day-to-day variations in sleep duration. Logistic regression models revealed that an increase in sleep duration, by 1·66 ± 0·52 h, lowered the odds of seizure by 27% in the following 48 h. Following a seizure, patients slept for longer durations and if a seizure occurred during sleep, then sleep quality was also reduced with increased time spent aroused from sleep and reduced rapid eye movement sleep.

INTERPRETATION

Our results suggest that day-to-day deviations from regular sleep duration correlates with changes in seizure probability. Sleeping longer, by 1·66 ± 0·52 h, may offer protective effects for patients with refractory focal epilepsy, reducing seizure risk. Furthermore, the occurrence of a seizure may disrupt sleep patterns by elongating sleep and, if the seizure occurs during sleep, reducing its quality.

Nocturnal sleep architecture in idiopathic hypersomnia: a systematic review and meta-analysis

BACKGROUND

Current sleep medicine nosology places increased importance on nocturnal polysomnographic sleep recordings in the diagnosis of central nervous system disorders of hypersomnolence, particularly idiopathic hypersomnia (IH).

OBJECTIVE

Determine what differences in sleep staging and architecture exist between IH and healthy controls using meta-analysis.

METHODS

Systematic review identified relevant studies that included nocturnal polysomnography data for IH and healthy control groups. Meta-analysis compared standardized mean differences (Hedge's g) for total sleep time (TST), sleep onset latency (SOL), sleep efficiency (SE), rapid eye movement (REM) sleep percentage, slow wave sleep (SWS) percentage, and REM latency (REML). Moderator analyses were also conducted for variables with significant heterogeneity among studies.

RESULTS

The meta-analysis included 10 studies. Relative to controls, IH demonstrated increased TST (pooled g = 0.92; 95% CI: 0.46 to 1.38, p < 0.0001) and REM percentage (pooled g = 0.36, 95% CI: 0.09 to 0.64, p = 0.01), decreased SOL (pooled g = -0.46; 95% CI: -0.81 to -0.12, p = 0.009) and SWS percentage (pooled g = -0.28, 95% CI: -0.50 to -0.07, p = 0.01), without significant differences in SE (pooled g = 0.03; 95% CI: -0.32 to 0.38, p = 0.86) or REML (pooled g = 0.14, 95% CI: -0.21 to 0.49, p = 0.42). Moderator analysis demonstrated a significant effect of sex on SE, with a higher proportion of women to men significantly predicting lower SE between in IH and controls (p < 0.0001).

CONCLUSIONS

IH is associated with several changes in sleep staging and architecture relative to healthy persons, including alterations in REM and SWS not currently delineated in nosological constructs. Further research is indicated to clarify how these findings are related the pathophysiology of IH and related disorders.

Morning blood pressure is associated with sleep quality in obese adolescents

OBJECTIVE

To examine relationships among blood pressure (BP), adiposity, and sleep quality with the use of overnight polysomnography in obese adolescents.

STUDY DESIGN

Overnight polysomnogram and morning BP measurements were performed in obese (body mass index [BMI] >95th percentile) nondiabetic adolescents (eligible age range 12-18 years, n = 49). Subjects were stratified into 2 groups, one with normal BP, and one with elevated BP, and demographic and clinical characteristics were compared between the groups. Multiple linear regression analysis was used to assess the effects of sleep quality on BP.

RESULTS

Participants (n = 27) had a normal morning BP, and 22 (44.9%) had elevated morning BP. There were no differences in age (P = .53), sex (P = .44), race (P = .58), or BMI (P = .56) between the 2 BP groups. The group with elevated BP spent shorter percentages of time in rapid eye movement (REM; P = .006) and slow-wave sleep (SWS; P = .024). Multiple linear regression analysis showed that a lower percentage of both REM and SWS was associated with increased morning BP after we adjusted for pubertal stage, sex, race, and BMI.

CONCLUSION

Lack of deeper stages of sleep, REM sleep, and SWS is associated with greater morning BP in obese adolescents, independent of BMI. Poor sleep quality should be considered in the work-up of obese youth with hypertension. Intervention studies are needed to evaluate whether improving the quality of sleep will decrease BP elevation.

Deciphering the Interacting Mechanisms of Circadian Disruption and Alzheimer's Disease

Alzheimer's disease (AD) is one of the crucial causative factors for progressive dementia. Neuropathologically, AD is characterized by the extracellular accumulation of amyloid beta plaques and intracellular neurofibrillary tangles in cortical and limbic regions of the human brain. The circadian system is one of the many affected physiological processes in AD, the dysfunction of which may reflect in the irregularity of the sleep/wake cycle. The interplay of circadian and sleep disturbances inducing AD progression is bidirectional. Sleep-associated pathological alterations are frequently evident in AD. Understanding the interrelation between circadian disruption and AD may allow for earlier identification of AD pathogenesis as well as better suited approaches and potential therapies to combat dementia. In this article, we examine the existing literature related to the molecular mechanisms of the circadian clock and interacting mechanisms of circadian disruption and AD pathogenesis.

Cyclic nature of the REM sleep-like state in the cuttlefish Sepia officinalis

Sleep is a state of immobility characterized by three key criteria: an increased threshold of arousal, rapid reversal to an alert state and evidence of homeostatic 'rebound sleep' in which there is an increase in the time spent in this quiescent state following sleep deprivation. Common European cuttlefish, Sepia officinalis, show states of quiescence during which they meet the last two of these three criteria, yet also show spontaneous bursts of arm and eye movements that accompany rapid changes in chromatophore patterns in the skin. Here, we report that this rapid eye movement sleep-like (REMS-like) state is cyclic in nature. Iterations of the REMS-like state last 2.42±0.22 min (mean±s.e.m.) and alternate with 34.01±1.49 min of the quiescent sleep-like state for durations lasting 176.89±36.71 min. We found clear evidence that this REMS-like state (i) occurs in animals younger than previously reported; (ii) follows an ultradian pattern; (iii) includes intermittent dynamic chromatophore patterning, representing fragments of normal patterning seen in the waking state for a wide range of signaling and camouflage; and (iv) shows variability in the intensity of expression of these skin patterns between and within individuals. These data suggest that cephalopods, which are mollusks with an elaborate brain and complex behavior, possess a sleep-like state that resembles behaviorally the vertebrate REM sleep state, although the exact nature and mechanism of this form of sleep may differ from that of vertebrates.

Functional roles of REM sleep

Rapid eye movement (REM) sleep is an enigmatic and intriguing sleep state. REM sleep differs from non-REM sleep by its characteristic brain activity and from wakefulness by a reduced anti-gravity muscle tone. In addition to these key traits, diverse physiological phenomena appear across the whole body during REM sleep. However, it remains unclear whether these phenomena are the causes or the consequences of REM sleep. Experimental approaches using humans and animal models have gradually revealed the functional roles of REM sleep. Extensive efforts have been made to interpret the characteristic brain activity in the context of memory functions. Numerous physical and psychological functions of REM sleep have also been proposed. Moreover, REM sleep has been implicated in aspects of brain development. Here, we review the variety of functional roles of REM sleep, mainly as revealed by animal models. In addition, we discuss controversies regarding the functional roles of REM sleep.

Repeated Administration of Korea Red Ginseng Extract Increases Non-Rapid Eye Movement Sleep via GABAAergic Systems

The current inquiry was conducted to assess the change in sleep architecture after long periods of administration to determine whether ginseng can be used in the therapy of sleeplessness. Following post-surgical recovery, red ginseng extract (RGE, 200 mg/ kg) was orally administrated to rats for 9 d. Data were gathered on the 1st, 5th, and 9th day, and an electroencephalogram was recorded 24 h after RGE administration. Polygraphic signs of unobstructed sleep-wake activities were simultaneously recorded with sleep-wake recording electrodes from 11:00 a.m. to 5:00 p.m. for 6 h. Rodents were generally tamed to freely moving polygraphic recording conditions. Although the 1st and 5th day of RGE treatment showed no effect on power densities in non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, the 9th day of RGE administration showed augmented α-wave (8.0 to 13.0 Hz) power densities in NREM and REM sleep. RGE increased total sleep and NREM sleep. The total percentage of wakefulness was only decreased on the 9th day, and the number of sleep-wake cycles was reduced after the repeated administration of RGE. Thus, the repeated administration of RGE increased NREM sleep in rats. The α-wave activities in the cortical electroencephalograms were increased in sleep architecture by RGE. Moreover, the levels of both α- and β-subunits of the γ-aminobutyric acid (GABA)_A receptor were reduced in the hypothalamus of the RGE-treated groups. The level of glutamic acid decarboxylase was over-expressed in the hypothalamus. These results demonstrate that RGE increases NREM sleep via GABA_Aergic systems.

The effect of childhood obstructive sleep apnea on ambulatory blood pressure is modulated by the distribution of respiratory events during rapid eye movement and nonrapid eye movement sleep

OBJECTIVE

We aimed to investigate if different childhood obstructive sleep apnea (OSA) subtypes, namely rapid eye movement (REM)-related, nonrapid eye movement (NREM)-related and stage-independent OSA would exert different effects on ambulatory blood pressure (ABP).

METHODS

Data from our previous school-based cross-sectional study were reanalyzed. Subjects who had an obstructive apnea-hypopnea index (OAHI) between 1 and 10 events per hour and a total REM sleep duration of >30min were included in our analysis. REM-related and NREM-related OSA were defined as a ratio of OAHI in REM sleep (OAHIREM) to OAHI in NREM sleep (OAHINREM) of >2 and <0.5, respectively. The others were classified as stage-independent OSA.

RESULTS

A total of 162 subjects were included in the analysis. In the mild OSA (OAHI, 1-5events/h) subgroup, no significant differences in any ABP parameters were found between OSA subtypes. On the other hand, in subjects with moderate OSA (OAHI, 5-10events/h), the REM-related OSA subtype had a significantly lower daytime systolic blood pressure (SBP) z score (-0.13±0.90 cf 1.15±0.67; P=.012) and nighttime SBP z score (0.29±1.06 cf 1.48±0.88, P=.039) than the stage-independent OSA subtype. Linear regression analyses revealed that OAHINREM but not OAHIREM was significantly associated with both daytime (P=.008) and nighttime SBP (P=.042) after controlling for age, gender, and body size.

CONCLUSION

Children with obstructive events mainly in REM sleep may have less cardiovascular complications than those with stage-independent OSA.

Non-REM sleep-disordered breathing affects performance on the psychomotor vigilance task

PURPOSE

Although many studies have investigated the clinical importance of sleep apnea on rapid eye movement (REM) and non-REM (NREM) sleep, the relationship between behavioral performance and apneic events during different sleep phases remains unclear. In the present study, we sought to investigate the effect of sleep phase fragmentation due to sleep-disordered breathing (SDB) during REM and NREM on the vigilance and sustainability of attention based on psychomotor vigilance task (PVT) performance.

METHODS

From a pool of subjects who underwent consecutive diagnostic polysomnography (PSG) for obstructive sleep apnea, 163 adult subjects with both REM and NREM sleep ≥ 30 min were enrolled for our study and performed a standardized 10-min PVT. The main outcome variables of the PVT were mean reaction time (RT), PVT Lapse count, and the slope of the reciprocal RT. Subjective sleepiness was measured using the Epworth Sleepiness Scale (ESS).

RESULTS

After multivariate linear regression analysis with adjustment for age, sex, body mass index, and the apnea-hypopnea index (AHI) of the counterpart sleep phase, we found that AHI during NREM (AHI_NREM) compared to AHI during REM (AHI_REM) was significantly associated with PVT lapses.

CONCLUSIONS

Our results suggest that SDB during NREM has a significant impact on vigilance lapses compared to that of REM.

Relevance of electroencephalogram assessment in amyloid and tau pathology in rat

In order to contribute to a better knowledge on the relationship between amyloid and tau pathology, and electroencephalography (EEG) disturbances, the aim of this study was to evaluate the effects of injection of beta amyloid Abeta(1-42) peptide, tau (a recombinant AAV (Adeno-Associated Virus) containing the human transgene tau with the P301 L mutation on rats and the combination of both, on the power of brain's rhythm (delta, theta, alpha, beta and gamma waves) during the different sleep/wake states of animals by EEG recording. Currently, no preclinical studies explore the effect of the tau pathology on EEG. The experimentations were performed 3 weeks and 3 months post injections. Beta amyloid deposits and hyperphosphorylated Tau are observed by immunohistofluorescence, only in the hippocampus. Furthermore, using a radial arm water maze, the main effect was observed on working memory which was significantly impaired in Abeta-Tau group only 3 months post injections. However, on EEG, as early as the 3^rd week, an overall decrease of the EEG bands power was observed in the treated groups, particularly the theta waves during the rapid eye movement (REM) sleep. Beta amyloid was mainly involved in these perturbations. Obviously, EEG seems to be an interesting tool in the early diagnostic of amyloid and tau pathologies, with a good sensitivity and the possibility to perform a follow up during a large period.

Unaltered EEG spectral power and functional connectivity in REM microstates in frequent nightmare recallers: are nightmares really a REM parasomnia?

BACKGROUND

Frequent nightmares show signs of hyperarousal in NREM sleep. Nevertheless, idiopathic nightmare disorder is considered a REM parasomnia, but the pathophysiology of REM sleep in relation to frequent nightmares is controversial. Cortical oscillatory activity in REM sleep is largely modulated by phasic and tonic REM periods and seems to be linked to different functions and dysfunctions of REM sleep. Here, we examined cortical activity and functional synchronization in frequent nightmare recallers and healthy controls, during phasic and tonic REM.

METHODS

Frequent nightmare recallers (N = 22) and healthy controls (N = 22) matched for high dream recall spent two nights in the laboratory. Phasic and tonic REM periods from the second nights' recordings were selected to examine differences in EEG spectral power and weighted phase lag index (WPLI) across groups and REM states.

RESULTS

Phasic REM showed increased power and synchronization in delta and gamma frequency bands, whereas tonic REM featured increased power and synchronization in the alpha and beta bands. In the theta band, power was higher during tonic, and synchronization was higher during phasic REM sleep. No differences across nightmare and control participants or patterns representing interactions between the groups and REM microstates emerged.

CONCLUSIONS

Our findings do not support the idea that abnormal REM sleep power and synchronization play a role in the pathophysiology of frequent nightmares. Altered REM sleep in nightmare disorder could have been confounded with comorbid pathologies and increased dream recall, or might be linked to more specific state factors (nightmare episodes).

Challenges in sleep stage R scoring in patients with autosomal dominant spinocerebellar ataxias (SCA1, SCA2 and SCA3) and oculomotor abnormalities: a whole night polysomnographic evaluation

OBJECTIVES

Spinocerebellar ataxias are progressive neurodegenerative disorders characterized by progressive cerebellar features with additional neuro-axis involvement. Oculomotor abnormality is one of the most frequent manifestations. This study was done to assess the polysomnographic abnormalities in patients with Spinocerebellar ataxia (SCA1, SCA2 and SCA3) and also to evaluate whether oculomotor abnormalities interfere with sleep stage R scoring.

METHODS

The study was carried out using 36 genetically positive SCA patients. All patients underwent neurological examination with special focus on oculomotor function (optokinetic nystagmus-OKN and extraocular movement restriction-EOM). The sleep quality was measured with Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). Disease severity was assessed with International Cooperative Ataxia Rating Scale (ICARS). All the patients underwent over-night video-polysomnography (VPSG).

RESULTS

Out of 36 patients studied, the data of 34 patients [SCA1 (n = 12), SCA2 (n = 13), SCA3 (n = 9)] were used for final analysis. Patients from SCA1, SCA2, and SCA3 category did not show significant differences in age and diseases severity (ICARS). All patients had vertical OKN impairment. Oculomotor impairment was higher in SCA2 patients. Sleep macro-architecture analysis showed absent stage R sleep, predominantly in SCA2 (69%) followed by SCA3 (44%) and SCA1 (8%). Patients showed a strong negative correlation of stage R sleep percentage with disease severity and oculomotor dysfunction.

CONCLUSION

Voluntary saccadic eye movement velocity and rapid eye movements (REMs) in sleep are strongly correlated. The more severe the saccadic velocity impairment, the less likely was it to generate REMs (rapid eye movements) during stage R. Accordingly 69% of SCA2 patients with severe occulomotor impairments showed absent stage R as per the AASM sleep scoring. We presume that the impaired REMs generation in sleep could be due to oculomotor abnormality and has resulted in spuriously low or absent stage R sleep percentage in SCA patients with conventional VPSG scoring rules. The present study recommends the modification of AASM scoring rules for stage R in patients with oculomotor abnormalities.

The association of changes of sleep architecture related to donepezil: A systematic review and meta-analysis

BACKGROUND

Donepezil had been recognized to have impact on sleep quality in demented patients. However, there was insufficient evidences about the actual effect of donepezil in the sleep architectures. Our meta-analysis aimed to evaluate the changes of sleep architectures related to donepezil use.

METHODS

Followed the PRISMA2020 and AMSTAR2 guidelines, electronic search had been performed on the databases of PubMed, Embase, ScienceDirect, ClinicalKey, Cochrane CENTRAL, ProQuest, Web of Science, and ClinicalTrials.gov. The outcome measurement was changes of sleep parameters detected by polysomnography. A random-effects meta-analysis was conducted.

RESULTS

Total twelve studies had been involved. The percentage of REM sleep would significantly increase after donepezil treatment (Hedges' g = 0.694, p < 0.001). Compared to placebo/controls, subjects with donepezil would had significantly increased percentage of REM sleep stage (Hedges' g = 0.556, p = 0.018). Furthermore, donepezil was also associated with the decreased stage 2 sleep percentage, sleep efficiency, or total sleep time in different analysis conditions.

CONCLUSION

Our meta-analysis provided detailed changes of sleep architectures related to donepezil treatment. Further larger sample size studies with stricter control of potential moderators are needed to clarify these issues.

Association between REM sleep and obstructive sleep apnea in obese and overweight adolescents

PURPOSE

Overweight and obese children have demonstrated reduced rapid eye movement (REM) sleep, affecting energy balance regulation and predisposition to weight gain. Obstructive sleep apnea (OSA) is a known cause of decreased REM sleep. The purpose of this study is to examine the association between the percentage of REM sleep, BMI z-score, and OSA severity in overweight and obese adolescents.

METHODS

We performed a cross-sectional study of 92 (43% female) overweight and obese adolescents (13-17 years old) who underwent overnight polysomnography (PSG) at Children's Hospital Los Angeles between 2010 and 2017.

RESULTS

The average Body Mass Index (BMI) z-score was 2.27 ± 0.47, with 71% having BMI z-score ≥ 2. REM% during PSG was 15.6 ± 6.8, and obstructive apnea-hypopnea index was 17.1 ± 24.3. The distribution across categories of OSA severity was 27% none (≤ 1.5 events/h), 24% mild (> 1.5-5 events/h), 8% moderate (> 5-10 events/h), and 41% severe (> 10 events/h). REM% was not associated with BMI z-score, either on univariate or multivariate regression with adjustment for age, gender, and apnea-hypopnea index (AHI). When subdivided into OSA categories, a 1-unit increase in BMI z-score was associated with a 5.96 (p = 0.03) increase in REM% in mild OSA and an 8.86 (p = 0.02) decrease in REM% in severe OSA. There was no association between BMI z-score and REM% in none and moderate OSA.

CONCLUSION

Among overweight and obese adolescents, BMI z-score was associated with decreased REM% in severe OSA and unexpectedly increased REM% in mild OSA, but there was no association in none or moderate OSA.

Early life sleep disruption has long lasting, sex specific effects on later development of sleep in prairie voles

In mammals, sleep duration is highest in the early postnatal period of life and is critical for shaping neural circuits that control the development of complex behaviors. The prairie vole is a wild, highly social rodent that serves as a unique model for the study of complex, species-typical social behaviors. Previous work in our laboratory has found that early life sleep disruption (ELSD) in prairie voles during a sensitive window of postnatal development leads to long lasting changes in social and cognitive behaviors as well as structural changes in excitatory and inhibitory neural circuits in the brain. However, it is currently unknown how later sleep is impacted by ELSD, both shortly after ELSD and over the long term. Therefore, the aim of this study was to describe the effects of ELSD on later life sleep, compared to sleep in normally developing prairie voles. First, we conducted tethered electroencephalogram/electromyogram (EEG/EMG) recordings in juvenile prairie voles undergoing ELSD, compared to Control conditions. Second, we conducted 24 h of home cage tethered EEG/EMG recordings in either adolescent or adult male and female prairie voles that had previously undergone ELSD or Control conditions as juveniles. We found that, as adults, male ELSD prairie voles showed persistently lower REM sleep duration and female ELSD prairie voles showed persistently higher NREM sleep duration compared to Controls, but no other sleep parameters differed. We concluded that 1) persistent effects of ELSD on sleep into adulthood may contribute to the social and cognitive deficits observed in adult voles, and 2) sleep disruption early in life can influence later sleep patterns in adulthood.

Current Understanding of Narcolepsy 1 and its Comorbidities: What Clinicians Need to Know

Narcolepsy is a chronic neurologic disorder associated with the dysregulation of the sleep–wake cycle that often leads to a decreased quality of life and results in a considerable health burden. There is often a delay to diagnosis of narcolepsy, mainly due to the lack of recognition of this disorder. One of the main factors hindering the diagnosis of narcolepsy is the association of comorbidities, which include other sleep disorders, psychiatric disorders, cardiovascular disorders, and metabolic disorders. The signs and symptoms of these comorbidities often overlap with those of narcolepsy, and some of the medications used for their treatment may obscure the symptoms of narcolepsy, leading to a delay in diagnosis. This review is targeted to clinicians unaccustomed to working with sleep disorders and aims to increase recognition and improve the management of narcolepsy.

Rapid eye movement related obstructive sleep apnea: Where do we stand?

Rapid eye movement (REM) related obstructive sleep apnea (OSA) is defined by the presence of episodes of apnea or hypopnea predominantly or exclusively during REM sleep. Epidemiology of this disorder shows a complex interaction with age, sex, and body mass index. The prevalence is variable and depends on the criteria used to define this disorder. Moreover, the clinical significance of this entity remains poorly defined. However, episodes of apnea or hypopnea encountered during REM sleep are longer and are associated with a more profound drop in oxygen saturation than non-REM sleep. Likewise, this disorder may be independently associated with hypertension and poor glycemic control. More importantly, positive airway pressure therapy as currently prescribed may not treat the majority of apnea episodes during REM sleep. The treatment is further complicated by the different definitions used for the diagnosis of this disorder and the lack of consensus if patients with this diagnosis should be treated if their overall apnea-hypopnea index does not meet the threshold for the clinical diagnosis of OSA. The definition and treatment used for the diagnosis and management of REM-related OSA needs to be standardized. Moreover, a consensus needs to be developed as to whether patients with this disorder should be treated if their overall apnea-hypopnea index does not meet the threshold for the clinical diagnosis of OSA. Further investigation may help answer if this disorder is independently associated with neurocognitive and cardiometabolic adverse outcomes and help guide the therapeutic approach.

Rapid eye movement-sleep is reduced in patients with acute uncomplicated diverticulitis-an observational study

Introduction. Sleep disturbances are commonly found in patients in the postoperative period. Sleep disturbances may give rise to several complications including cardiopulmonary instability, transient cognitive dysfunction and prolonged convalescence. Many factors including host inflammatory responses are believed to cause postoperative sleep disturbances, as inflammatory responses can alter sleep architecture through cytokine-brain interactions. Our aim was to investigate alteration of sleep architecture during acute infection and its relationships to inflammation and clinical symptoms. Materials & Methods. In this observational study, we included patients with acute uncomplicated diverticulitis as a model to investigate the isolated effects of inflammatory responses on sleep. Eleven patients completed the study. Patients were admitted and treated with antibiotics for two nights, during which study endpoints were measured by polysomnography recordings, self-reported discomfort scores and blood samples of cytokines. One month later, the patients, who now were in complete remission, were readmitted and the endpoints were re-measured (the baseline values). Results. Total sleep time was reduced 4% and 7% the first (p = 0.006) and second (p = 0.014) nights of diverticulitis, compared to baseline, respectively. The rapid eye movement sleep was reduced 33% the first night (p = 0.016), compared to baseline. Moreover, plasma IL-6 levels were correlated to non-rapid eye movement sleep, rapid eye movement sleep and fatigue. Conclusion. Total sleep time and rapid eye movement sleep were reduced during nights with active diverticulitis and correlated with markers of inflammation.

Apnea hypopnea indices categorized by REM/NREM sleep and sleep positions in 100 children with adenotonsillectomy for obstructive sleep apnea disease

OBJECTIVES

In pediatric obstructive sleep apnea (OSA), the relationship between rapid eye movement sleep and upper airway collapse, and between sleep position and airway dimensions are well known. However, the interrelations between these factors and the obstructive apnea hypopnea index (O-AHI) have not been thoroughly investigated.

METHODS

A retrospective study including 100 children who underwent adenotonsillectomy between March 2010 and July 2017. Total O-AHI was divided into four subcategories by sleep stage and position.

RESULTS

Preoperatively 14 of 47 mild cases of OSA (1 ≤ total O-AHI) and 17 of 18 moderate (5 ≤ total O-AHI) had time showing severe apnea (10 ≤ subcategorized O-AHI). Twenty-two of 24 severe cases (10 ≤ total O-AHI) exhibited very severe apnea (30 ≤ subcategorized O-AHI). All 11 very severe cases (30 ≤ total O-AHI) experienced more than 50 apnea events per hour in at least one of the O-AHI subcategories. After surgery, 23 of 70 cases classified as completely resolved (total O-AHI < 1) still had mild apnea in the O-AHI subcategories, and six of 13 cases who continued to experience apnea events had moderate-to-severe apnea. Seventeen cases worsened in the O-AHI subcategories, and total O-AHI deteriorated in two cases of the 17. The amount of REM sleep and use of the supine position increased significantly postoperatively in the quartile groups with the lowest baseline values (p < 0.0001).

CONCLUSIONS

When an unexpected AHI value is encountered, the O-AHI subcategories may be informative regarding the indications for surgery and evaluating the efficacy thereof.

The impacts of ambient relative humidity and temperature on supine position-related obstructive sleep apnea in adults

Obstructive sleep apnea (OSA) is associated with seasonal variations. The objective of this study was to examine associations of ambient relative humidity (RH) and temperature on sleep parameters. We conducted a cross-sectional study by retrospectively recruiting 5204 adults from a sleep center in Taipei, Taiwan. Associations of 1-night polysomnography with ambient RH and temperature in 1-day, 7-day, 1-month, 6-month, and 1-year averages were examined using linear regression models and a mediation analysis. RH increase was associated with snoring index decrease and apnea/hypopnea index (AHI) increase. Temperature increase was associated with decreases in sleep efficiency and the AHI, and increases in the wake time after sleep onset and snoring index. RH increase was inversely associated with non-rapid eye movement (NREM) sleep stage I (N1), III (N3), and rapid eye movement (REM) sleep, but positively associated with the NREM sleep stage II (N2) stage. Temperature increase was associated with N1, N2, and N3 sleep. An increase in RH was associated with an increase in the arousal index and a decrease in the < 95% arterial oxygen saturation (SaO2) among total, REM, and NREM sleep, whereas a temperature increase was associated with a decrease in the arousal index and an increase in < 95% SaO2 among total, REM, and NREM sleep. An increase in RH was associated with increases in the time spent in a supine posture and the supine AHI. An increase in temperature was associated with decreases in the supine posture, supine AHI, and non-supine AHI. The N3 sleep stage was an important mediator in increasing the supine AHI with a long-term increase in RH. But the N1 and N2 sleep stages mediated a decrease in the supine AHI with an increase in RH. In conclusion, ambient RH and temperature were associated with alterations in sleep parameters in adults, which were mediated by the sleep cycle. An understanding of outdoor environments has important implications for diagnostic classifications in the supine dominance of OSA in adults.

Breathtaking dreams: reduced REM phenotype in REM-related sleep apnea

PURPOSE

The expression of the respiratory events in OSA is influenced by different mechanisms. In particular, REM sleep can highly increase the occurrence of events in a subset of OSA patients, a condition dubbed REM-OSA (often defined as an AHI 2 times higher in REM than NREM sleep). However, a proper characterization of REM-OSA and its pathological sequelae is still inadequate, partly because of limitations in the current definitions.

METHODS

We propose a new interpretation of the REM-OSA definition, extending it from a AHI-ratio to a two-dimensional space, considering both time and events ratios in REM over NREM separately. Within this space, we analyzed current definitions of REM-OSA in three large clinical dataset and identified the underlying sources of heterogeneity.

RESULTS

We observed that REM-OSA and REM-independent-OSA subgroups exist. Some subgroups exhibited abnormal REM characteristics (e.g., REM-OSA with reduced time in REM). Others had OSA features that are intermediate between REM-independent-OSA participants and those with a clear disproportion of REM events.

CONCLUSION

We found that a time and events' ratio of REM and NREM allow a more precise characterization of REM-OSA subgroups. Our new interpretation can be used to bolster new research into REM-OSA pathophysiological mechanisms.

A novel postoperative delayed neurocognitive recovery model established based on preoperative rapid eye movement sleep deprivation in adult mice

BACKGROUNDS

Postoperative delayed neurocognitive recovery (dNCR) usually occurs in older patients, however, the extremely high cost of older animals has hindered postoperative dNCR research to some extent. Preoperative sleep disturbance increases the risk of postoperative dNCR in patients. Therefore, this study aimed to construct a dNCR model in adult mice based on preoperative sleep disturbance.

METHODS

A modified multiple platform method was used to induce rapid eye movement sleep deprivation (REM-SD), and the surgical model was established by laparotomy in 3-month-old C57BL/6 J mice. The Morris water maze and fear conditioning test were used to assess the cognitive function of mice. Immunofluorescence was used to detect microglia and astrocyte activation, and quantitative real-time PCR was used to measure the mRNA levels of inflammatory cytokines.

RESULTS

Neither laparotomy nor 12 h of REM-SD caused cognitive impairment in mice, but the combination of the two methods induced hippocampus-dependent cognitive dysfunction. Furthermore, hippocampal microglia of mice with 12 h of preoperative REM-SD were polarized to the M1-type, accompanied by increased interleukin-6 and decreased interleukin-10 at the mRNA level.

CONCLUSIONS

We successfully established an adult mouse model of postoperative dNCR based on preoperative REM-SD, which provides an alternative model to explore the pathogenesis and therapeutic measures of dNCR.