First-night effect in normal subjects and psychiatric inpatients

Validation of the French version of the Munich ChronoType questionnaire and associations between chronotype and physiological parameters

Assessing chronotype is essential in clinical and research environments, but the Munich ChronoType Questionnaire (MCTQ), a widely utilised tool, is not available in French. Therefore, we carried out an observational monocentric study to validate the French MCTQ against the sleep diary for sleep schedules, the Morningness-Eveningness Questionnaire (MEQ) for chronotype, and polysomnography measures. We utilised the mid-sleep point on free days (MSF), adjusted for sleep debt (MSFsc), to gauge morningness/eveningness. The study included 80 participants (average age: 40.9 years, 50% female). The sleep schedules determined by the MCTQ and the sleep diary showed a high correlation. The MSFsc demonstrated a significant correlation with the MEQ, persisting even under sleep constraints such as an alarm on free days. The predictive accuracy was strong for a morning chronotype and moderate for an evening chronotype as assessed using the MEQ. In summary, the French MCTQ is a reliable tool for researchers and clinicians for assessing sleep schedules and chronotype in French-speaking populations. The MSFsc can effectively predict chronotype, even under sleep constraints. However, for the evening chronotype, self-assessment appears to be more accurate. The association with polysomnography measures enriches our understanding of the chronotype at the intersection of behaviour and physiology.

Effects of evening smartphone use on sleep and declarative memory consolidation in male adolescents and young adults

Exposure to short-wavelength light before bedtime is known to disrupt nocturnal melatonin secretion and can impair subsequent sleep. However, while it has been demonstrated that older adults are less affected by short-wavelength light, there is limited research exploring differences between adolescents and young adults. Furthermore, it remains unclear whether the effects of evening short-wavelength light on sleep architecture extend to sleep-related processes, such as declarative memory consolidation. Here, we recorded polysomnography from 33 male adolescents (15.42 ± 0.97 years) and 35 male young adults (21.51 ± 2.06 years) in a within-subject design during three different nights to investigate the impact of reading for 90 min either on a smartphone with or without a blue-light filter or from a printed book. We measured subjective sleepiness, melatonin secretion, sleep physiology and sleep-dependent memory consolidation. While subjective sleepiness remained unaffected, we observed a significant melatonin attenuation effect in both age groups immediately after reading on the smartphone without a blue-light filter. Interestingly, adolescents fully recovered from the melatonin attenuation in the following 50 min before bedtime, whereas adults still, at bedtime, exhibited significantly reduced melatonin levels. Sleep-dependent memory consolidation and the coupling between sleep spindles and slow oscillations were not affected by short-wavelength light in both age groups. Nevertheless, adults showed a reduction in N3 sleep during the first night quarter. In summary, avoiding smartphone use in the last hour before bedtime is advisable for adolescents and young adults to prevent sleep disturbances. Our research empirically supports general sleep hygiene advice and can inform future recommendations regarding the use of smartphones and other screen-based devices before bedtime.

Respiration-triggered olfactory stimulation reduces obstructive sleep apnea severity: A prospective pilot study

Obstructive sleep apnea is a prevalent sleep-disordered breathing condition characterized by repetitive reduction in breathing during sleep. The current care standard for obstructive sleep apnea is continuous positive air pressure devices, often suffering from low tolerance due to limited adherence. Capitalizing on the unique neurocircuitry of olfactory perception and its retained function during sleep, we conducted a pilot study to test transient, respiration-based olfactory stimulation as a treatment for obstructive sleep apnea markers. Thirty-two patients with obstructive sleep apnea (apnea-hypopnea index ≥ 15 events per hr) underwent two polysomnography sessions, "Odour" and "Control", in random order. In "Odour" nights, patients were presented with transient respiratory-based olfactory stimulation delivered via a computer-controlled commercial olfactometer (Scentific). The olfactometer, equipped with a wireless monitoring, analysed respiratory patterns and presented odour upon detection of respiratory events. No odours were presented in "Control" nights. Following exclusions, 17 patients entered the analysis (four women, 47.4 (10.5) years, body mass index: 29.4 (6.3) kg m-2). We observed that olfactory stimulation during sleep reduced the apnea-hypopnea index ("Odour": 17.2 (20.9), "Control": 28.2 (18.6), z = -3.337, p = 0.000846, BF10 [Bayesian Factor 10]= 57.9), reflecting an average decrease of 31.3% in the number of events. Relatedly, stimulation reduced the oxygen desaturation index by 26.9% ("Odour": 12.5 (15.8), "Control": 25.7 (25.9), z = -3.337, p = 0.000846, BF10 = 9.522). This effect was not linked to the severity of baseline obstructive sleep apnea markers (ρ = -0.042, p = 0.87). Olfactory stimulation did not arouse from sleep or affect sleep structure, measured as time per sleep stage (F1,16 = 0.088, p = 0.77). In conclusion, olfactory stimulation during sleep was effective in reducing the severity of obstructive sleep apnea markers without inducing arousals, and may provide a novel treatment for obstructive sleep apnea, prompting continued research.

Insomnia-related rodent models in drug discovery

Despite the widespread prevalence and important medical impact of insomnia, effective agents with few side effects are lacking in clinics. This is most likely due to relatively poor understanding of the etiology and pathophysiology of insomnia, and the lack of appropriate animal models for screening new compounds. As the main homeostatic, circadian, and neurochemical modulations of sleep remain essentially similar between humans and rodents, rodent models are often used to elucidate the mechanisms of insomnia and to develop novel therapeutic targets. In this article, we focus on several rodent models of insomnia induced by stress, diseases, drugs, disruption of the circadian clock, and other means such as genetic manipulation of specific neuronal activity, respectively, which could be used to screen for novel hypnotics. Moreover, important advantages and constraints of some animal models are discussed. Finally, this review highlights that the rodent models of insomnia may play a crucial role in novel drug development to optimize the management of insomnia.

Validity and reliability of the Oura Ring Generation 3 (Gen3) with Oura sleep staging algorithm 2.0 (OSSA 2.0) when compared to multi-night ambulatory polysomnography: A validation study of 96 participants and 421,045 epochs

PURPOSE

To evaluate the validity and the reliability of the Oura Ring Generation 3 (Gen3) with Oura Sleep Staging Algorithm 2.0 (OSSA 2.0) through multi-night polysomnography (PSG).

PARTICIPANTS AND METHODS

Participants were 96 generally healthy Japanese men and women aged between 20 and 70 years contributing with 421,045 30-s epochs. Sleep scoring was performed according to American Academy of Sleep Medicine criteria. Each participant could contribute with a maximum of three polysomnography (PSG) nights. Within-participant means were created for each sleep measure and paired t-tests were used to compare equivalent measures obtained from the PSG and Oura Rings (non-dominant and dominant hand). Agreement between sleep measures were assessed using Bland-Altman plots. Interrater reliability for epoch accuracy was determined by prevalence-adjusted and bias-adjusted kappa (PABAK).

RESULTS

The Oura Ring did not significantly differ from PSG for the measures time in bed, total sleep time, sleep onset latency, sleep period time, wake after sleep onset, time spent in light sleep, and time spent in deep sleep. Oura Rings worn on the non-dominant- and dominant-hand underestimated sleep efficiency by 1.1 %-1.5 % and time spent in REM sleep by 4.1-5.6 min. The Oura Ring had a sensitivity of 94.4 %-94.5 %, specificity of 73.0 %-74.6 %, a predictive value for sleep of 95.9 %-96.1 %, a predictive value for wake of 66.6 %-67.0 %, and accuracy of 91.7 %-91.8 %. PABAK was 0.83-0.84 and reliability was 94.8 %. Sleep staging accuracy ranged between 75.5 % (light sleep) and 90.6 % (REM sleep).

CONCLUSIONS

The Oura Ring Gen3 with OSSA 2.0 shows good agreement with PSG for global sleep measures and time spent in light and deep sleep.

The insensitivity of sleep to an unfamiliar sleeping environment in patients with insomnia disorder

BACKGROUND

Sleeping in an unfamiliar environment, such as a sleep laboratory, is thought to disturb sleep in healthy individuals and could express a hyperarousal state called the first night effect. Insomnia disorder (ID) is a highly prevalent health problem characterized by increased arousal during the night and daytime. Whether or not a similar phenomenon occurs in patients with ID is unclear. This study aimed to investigate the effect of an unfamiliar environment on the sleep of patients with ID.

METHODS

In an unfamiliar sleep laboratory, polysomnographic recording testing was performed for two consecutive nights in patients with ID and age- and sex-matched healthy control subjects (HC). We collected sleep diaries and questionnaires regarding sleep, medical conditions, psychological status, and health history. Sleep continuity and architecture in both groups were compared and analyzed for two consecutive nights.

RESULTS

Participants with ID (n = 39)  and HC (n = 35) demonstrated differentially poor sleep on laboratory adaptation after exposure to the sleep laboratory. Patients with ID had longer rapid eye movement (REM) latency on the first night than on the second sleep night. HC showed increased duration and percentage of N1, decreased duration and percentage of N3, and decreased REM percentage during initial nights compared to subsequent nights. The other sleep variables showed no differences between the first and second sleep nights in patients with ID and HC.

CONCLUSIONS

An unfamiliar sleep environment does not aggravate the disruption of sleep continuity and sleep architecture but only affects the REM latency in patients with ID compared with HC.

Diagnostic accuracy of daytime polysomnography: a reappraisal during the COVID-19 era

Level I conventional polysomnography (PSG), the gold standard for diagnosing obstructive sleep apnea (OSA), requires an overnight stay. This study evaluated the role of daytime PSG as an alternative diagnostic tool. A prospective cohort study was undertaken with consecutive patients with suspected OSA at a tertiary care sleep center. The primary objective was to evaluate the sensitivity and diagnostic accuracy of daytime PSG for diagnosing OSA. The secondary objective was to find out the factors associated with a falsely negative daytime PSG result. All individuals were subjected to level I daytime PSG, done in the sleep lab in the presence of an experienced sleep technician during the daytime from 12 PM to 4 PM. Out of 162 patients, 105 underwent daytime PSG. OSA was diagnosed on daytime PSG in 86.7 out of the 19 remaining patients refused a repeat PSG study. Out of the 12 individuals who underwent the nighttime PSG for confirmatory diagnosis, 10 were diagnosed as OSA (false negatives), and 2 were confirmed as not-OSA (true negatives). The sensitivity, diagnostic accuracy, and negative predictive value of daytime PSG were 89.58%, 89.80%, and 16.67%, respectively. The false negatives had a higher prevalence of mild OSA. Daytime PSG is sensitive in diagnosing OSA and can be considered in individuals with severe symptoms at centers with a high patient load or when the individual wishes to avoid a nighttime study. A negative result in daytime PSG must be followed by conventional overnight PSG for confirmatory diagnosis.

First-night effect in insomnia disorder: a systematic review and meta-analysis of polysomnographic findings

Polysomnographic studies have been performed to investigate the first-night effect in insomnia disorder. However, these studies have revealed discrepant findings. This meta-analysis aimed to summarise and quantify the characteristics of the first-night effect in insomnia disorder. We performed a systematic search of the PubMed, Medline, EMBASE, Web of Science and PsycINFO databases to identify studies published through October 2019. A total of 11,862 articles were identified, and seven studies with eight independent populations were included in the meta-analysis. A total of 639 patients with insomnia disorder and 171 healthy controls underwent more than 2 consecutive nights of in-laboratory polysomnography. Pooled results demonstrated that both variables of sleep continuity and sleep architecture, other than slow-wave sleep were significantly altered in the first-night effect in insomnia disorder. Furthermore, the results indicated that patients with insomnia disorder had a disruption of sleep continuity in the first-night effect, including increased sleep onset latency and reduced total sleep time, compared to healthy controls. Overall, the findings show that patients with insomnia disorder experience the first-night effect, rather than reverse first-night effect, and the profiles of the first-night effect in patients with insomnia are different from healthy controls. These indicate that an adaptation night is necessary when sleep continuity and sleep architecture is to be studied in patients with insomnia disorder. More well-designed studies with large samples are needed to confirm the results.

The first-night effect and the consistency of short sleep in insomnia disorder

The nature and degree of objective sleep impairments in insomnia disorder remain unclear. This issue is complicated further by potential changes in sleep architecture on the first compared with subsequent nights in the laboratory. Evidence regarding differential first-night effects in people with insomnia disorder and controls is mixed. Here, we aimed to further characterize insomnia- and night-related differences in sleep architecture. A comprehensive set of 26 sleep variables was derived from two consecutive nights of polysomnography in 61 age-matched patients with insomnia and 61 good sleeper controls. People with insomnia expressed consistently poorer sleep than controls on several variables during both nights. While poorer sleep during the first night was observed in both groups, there were qualitative differences regarding the specific sleep variables expressing a first-night effect. Short sleep (total sleep time < 6 hr) was more likely during the first night and in insomnia, although approximately 40% of patients with insomnia presenting with short sleep on night 1 no longer met this criterion on night 2, which is important given the notion of short-sleeping insomnia as a robust subtype.

Reciprocal first night effect on rhythmic and non-rhythmic oromotor episodes in moderate to severe primary sleep bruxism: A retrospective physiological study

BACKGROUND

Sleep on the first night in a sleep laboratory is characterized by a lower sleep quality and frequency of rhythmic masticatory muscle activity (RMMA) than that on the second night in moderate to severe sleep bruxism (SB) patients.

OBJECTIVE

The aims of this study was to clarify the physiological factors contributing to the first night effect on oromotor activity during sleep and investigate whether physiological factors involved in the first night effect differed between rhythmic and non-rhythmic oromotor activities.

METHODS

Polysomnographic data collected on two consecutive nights from 15 moderate to severe SB subjects (F 7: M 8; age: 23.2 ± 1.3 [mean ± SD] years) were retrospectively analysed. Sleep variables, RMMA and non-specific masticatory muscle activity (NSMA) were scored in relation to episode types (i.e. phasic or tonic and cluster or isolated), sleep architecture and transient arousals. The relationships between nightly differences in oromotor and sleep variables were assessed. The distribution of oromotor events, arousals, cortical electroencephalographic power, RR intervals and heart rate variability were examined in relation to sleep cycle changes. These variables were compared between the first and second nights and between RMMA and NSMA.

RESULTS

Sleep variables showed a lower sleep quality on Night 1 than on Night 2. In comparisons with Night 1, the RMMA index increased by 18.8% (p  < .001, the Wilcoxon signed-rank test) on Night 2, while the NSMA index decreased by 17.9% (p  = .041). Changes in the RMMA index did not correlate with those in sleep variables, while changes in the NSMA index correlated with those in arousal-related variables (p  < .001, Spearman's rank correlation). An increase in the RMMA index on Night 2 was found for the cluster type and stage N1 related to sleep cyclic fluctuations in cortical and cardiac activities. In contrast, the decrease in the NSMA index was associated with increases in the isolated type and the occurrence of stage N2 and wakefulness regardless of the sleep cycle.

CONCLUSION

Discrepancies in first night effect on the occurrence of RMMA and NSMA represent unique sleep-related processes in the genesis of oromotor phenotypes in SB subjects.

Closed-Loop tACS Delivered during Slow-Wave Sleep Reduces Retroactive Interference on a Paired-Associates Learning Task

Previous studies have found a benefit of closed-loop transcranial alternating current stimulation (CL-tACS) matched to ongoing slow-wave oscillations (SWO) during sleep on memory consolidation for words in a paired associates task (PAT). Here, we examined the effects of CL-tACS in a retroactive interference PAT (ri-PAT) paradigm, where additional stimuli were presented to increase interference and reduce memory performance. Thirty-one participants were tested on a PAT before sleep, and CL-tACS was applied over the right and left DLPFC (F3 and F4) vs. mastoids for five cycles after detection of the onset of each discrete event of SWO during sleep. Participants were awoken the following morning, learned a new PAT list, and then were tested on the original list. There was a significant effect of stimulation condition (p = 0.04297; Cohen’s d = 0.768), where verum stimulation resulted in reduced retroactive interference compared with sham and a significant interaction of encoding strength and stimulation condition (p = 0.03591). Planned simple effects testing within levels of encoding revealed a significant effect of stimulation only for low-encoders (p = 0.0066; Cohen’s d = 1.075) but not high-encoders. We demonstrate here for the first time that CL-tACS during sleep can enhance the protective benefits on retroactive interference in participants who have lower encoding aptitude.

Pre-Sleep Cognitive Arousal Is Unrelated to Sleep Misperception in Healthy Sleepers When Unexpected Sounds Are Played during Non-Rapid Eye Movement Sleep: A Polysomnography Study

Background: It is well-established that environmental noise can disrupt sleep, and cause a mismatch between subjective and objective sleep, which is known as “sleep misperception”. Naturalistic studies indicate that pre-sleep cognitive arousal and sleep misperception are associated in the context of noise. However, it is not known if this is the case when ecologically valid noises are specifically played during non-rapid eye movement (NREM) sleep, which is susceptible to noise-related disruption. The present study evaluated if pre-sleep cognitive arousal was associated with sleep misperception in healthy normal sleepers, when unexpected ecologically valid common nocturnal noises were played during NREM sleep. Methods: Eighteen healthy sleepers (M_age = 23.37 years, SD_age = 3.21 years) participated. Sleep was measured objectively on three consecutive nights using polysomnography, in a sleep laboratory environment, and subjectively, through participant estimates of total sleep time (TST). Night 1 was a baseline night where no noises were played. On Night 2, noises, which were chosen to be representative of habitual nocturnal noises heard in home environments, were played to participants via in-ear headphones after 5 min of objective sleep. Results: Unexpectedly, habitual pre-sleep cognitive arousal was not associated with subjective–objective TST discrepancy on Night 2. Conclusions: These results suggest that in healthy sleepers, when ecologically valid noises are played unexpectedly during NREM sleep in an unfamiliar sleep laboratory environment the subjective experience of sleep is not associated with pre-sleep cognitive arousal, or negatively impacted by noise exposure.

Adaptive Solutions to the Problem of Vulnerability During Sleep

Sleep is a behavioral state whose quantity and quality represent a trade-off between the costs and benefits this state provides versus the costs and benefits of wakefulness. Like many species, we humans are particularly vulnerable during sleep because of our reduced ability to monitor the external environment for nighttime predators and other environmental dangers. A number of variations in sleep characteristics may have evolved over the course of human history to reduce this vulnerability, at both the individual and group level. The goals of this interdisciplinary review paper are (1) to explore a number of biological/instinctual features of sleep that may have adaptive utility in terms of enhancing the detection of external threats, and (2) to consider relatively recent cultural developments that improve vigilance and reduce vulnerability during sleep and the nighttime. This paper will also discuss possible benefits of the proposed adaptations beyond vigilance, as well as the potential costs associated with each of these proposed adaptations. Finally, testable hypotheses will be presented to evaluate the validity of these proposed adaptations.

The Implementation of Behavior Change Techniques in mHealth Apps for Sleep: Systematic Review

Background

Mobile health (mHealth) apps targeting health behaviors using behavior change techniques (BCTs) have been successful in promoting healthy behaviors; however, their efficacy with sleep is unclear. Some work has shown success in promoting sleep through mHealth, whereas there have been reports that sleep apps can be adverse and lead to unhealthy obsessions with achieving perfect sleep.

Objective

This study aims to report and describe the use of BCTs in mHealth apps for sleep with the following research questions: How many BCTs are used on average in sleep apps, and does this relate to their effectiveness on sleep outcomes? Are there specific BCTs used more or less often in sleep apps, and does this relate to their effectiveness on sleep outcomes? Does the effect of mHealth app interventions on sleep change when distinguishing between dimension and measurement of sleep?

Methods

We conducted a systematic review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to review articles on mHealth app interventions for sleep published between 2010 and 2020.

Results

A total of 12 studies met the eligibility criteria. Most studies reported positive sleep outcomes, and there were no negative effects reported. Sleep quality was the most common dimension of sleep targeted. Subjective measures of sleep were used across all apps, whereas objective measures were often assessed but rarely reported as part of results. The average number of BCTs used was 7.67 (SD 2.32; range 3-11) of 16. Of the 12 studies, the most commonly used BCTs were feedback and monitoring (n=11, 92%), shaping knowledge (n=11, 92%), goals and planning (n=10, 83%), and antecedents (n=10, 83%), whereas the least common were scheduled consequences (n=0, 0%), self-belief (n=0, 0%), and covert learning (n=0, 0%). Most apps used a similar set of BCTs that unfortunately did not allow us to distinguish which BCTs were present when studies reported more positive outcomes.

Conclusions

Our study describes the peer-reviewed literature on sleep apps and provides a foundation for further examination and optimization of BCTs used in mHealth apps for sleep. We found strong evidence that mHealth apps are effective in improving sleep, and the potential reasons for the lack of adverse sleep outcome reporting are discussed. We found evidence that the type of BCTs used in mHealth apps for sleep differed from other health outcomes, although more research is needed to understand how BCTs can be implemented effectively to improve sleep using mHealth and the mechanisms of action through which they are effective (eg, self-efficacy, social norms, and attitudes).

Development and Study of Ezzence: A Modular Scent Wearable to Improve Wellbeing in Home Sleep Environments

Ezzence is the first smartphone-controlled olfactometer designed for both day and night conditions. We discuss the design and technical implementation of Ezzence and report on a study to evaluate the feasibility of using the device in home-based sleep environments. The study results (N = 40) show that participants were satisfied with the device and found it easy to use. Furthermore, participants reported a significant improvement in sleep quality when using the device with scent in comparison to the control condition (p = 0.003), as well as better mood the following morning (p = 0.038) and shorter time to sleep onset (p = 0.008). The device is integrated with a wearable EEG and real-time sleep staging algorithm to release scent during specific sleep stages (N1, N2, N3, and REM), which is important for certain use cases (e.g., to study the effect of scent on REM dreams, or to improve memory consolidation with a re-exposure of scent during N2 and N3). Ezzence can be used for several applications, including those that require scent triggered day and night. They include targeted memory reactivation, longitudinal health treatments, therapy, and mental or physical exercises. Finally, this article proposes an interaction framework to understand relationships between scents and environments based on proxemic dimensions and passive or active interactions during sleep.

Examining First Night Effect on Sleep Parameters with hd-EEG in Healthy Individuals

Difficulty sleeping in a novel environment is a common phenomenon that is often described as the first night effect (FNE). Previous works have found FNE on sleep architecture and sleep power spectra parameters, especially during non-rapid eye movement (NREM) sleep. However, the impact of FNE on sleep parameters, including local differences in electroencephalographic (EEG) activity across nights, has not been systematically assessed. Here, we performed high-density EEG sleep recordings on 27 healthy individuals on two nights and examined differences in sleep architecture, NREM (stages 2 and 3) EEG power spectra, and NREM power topography across nights. We found higher wakefulness after sleep onset (WASO), reduced sleep efficiency, and less deep NREM sleep (stage 3), along with increased high-frequency NREM EEG power during the first night of sleep, corresponding to small to medium effect sizes (Cohen’s d ≤ 0.5). Furthermore, study individuals showed significantly lower slow-wave activity in right frontal/prefrontal regions as well as higher sigma and beta activities in medial and left frontal/prefrontal areas, yielding medium to large effect sizes (Cohen’s d ≥ 0.5). Altogether, these findings suggest the FNE is characterized by less efficient, more fragmented, shallower sleep that tends to affect especially certain brain regions. The magnitude and specificity of these effects should be considered when designing sleep studies aiming to compare across night effects.

Short Sleep Duration on the Night Before Surgery Is Associated With Postoperative Cognitive Decline in Elderly Patients: A Prospective Cohort Study

As the world is rapidly aging, and the number of elderly patients who undergo surgery is rising, postoperative cognitive decline among those patients has become an increasing healthcare problem. Although understanding the risk factors and mechanisms underlying the pathogenesis of postoperative cognitive decline is critically important from a preventative viewpoint, such knowledge and evidence are lacking. A growing body of evidence suggest an association between cognitive function and sleep duration. The purpose of this study was to investigate the association between postoperative cognitive function and sleep duration on the night before surgery using a wearable sleep tracker. In this 6-month prospective cohort study, we analyzed data from 194 patients aged ≥ 65 years who underwent elective non-cardiac and non-cranial surgery under general anesthesia. According to the sleep duration on the night before surgery, patients were categorized into following four groups: <5, 5–7, 7–9, and >9 h. Perioperative cognitive function and domains were assessed using a neuropsychological test battery, and the incidence and prevalence of cognitive decline over 6 months after surgery were analyzed using the multiple logistic regression analysis. During the 6-month follow-up period, 41 patients (21%) developed cognitive decline. The incidence of cognitive decline was significantly elevated for the patients with sleep duration < 5 h (vs. 7–9 h; surgical duration-adjusted odds ratio, 3.50; 95% confidence interval, 1.20–10.2; P < 0.05). The association between sleep duration and prevalence of cognitive decline was limited to the early postoperative period (at 1 week and 1 month). Among the cognitive domains assessed, attentional function was significantly impaired in patients with a sleep duration < 5 h [vs. 7–9 h at 1 week; 4/37 (10.8%) vs. 0/73 (0%); P < 0.05]. In conclusion, sleep duration < 5 h on the night before surgery was significantly associated with worse attentional function after surgery and higher incidence of cognitive decline. The present results indicate that sleep deprivation on the night before surgery may have a temporary but significantly negative influence on the patient's postoperative cognitive function and is a potential target for preventing cognitive decline.

A meta-analysis of the first-night effect in healthy individuals for the full age spectrum

OBJECTIVES

The first-night effect (FNE) affects the accuracy of polysomnography (PSG) findings. However, the levels of FNE in different ages are unclear.

METHODS

We searched PubMed, Cochrane Library, Embase and Web of Science. The studies that reported sleep parameters by PSG for at least 2 consecutive nights from healthy individuals were included. The weighted mean differences were used to assess the effect size of differences in each sleep parameters between the first and second nights, as well as between the second and the third.

RESULTS

A total of 53 studies from 1422 subjects with mean age of 9.2-85.5 years were included. Meta-analyses showed that prolonged sleep onset latency, wake time after sleep onset and rapid eye movement sleep (REM) latency, accompanied by decreased total sleep time, sleep efficiency, and REM and increased non-rapid eye movement sleep stage 1 (N1) during the first night compared to the second (all P-value ≤ 0.001). No significant differences were observed in N2 and slow wave sleep, apnea-hypopnea index or periodic limb movement index (all P-value > 0.5). A non-linear association between FNE and age was observed: young adults (age 20-29 years) had the lowest level of FNE compared to other age ranges. Moreover, no significant differences were observed in most sleep parameters between the second and third night except more N2 and less REM in the second night (both P-value < 0.05).

CONCLUSIONS

The FNE exists in most cases but only in the first night of PSG recording and is less pronounced among young adults.

Mobile Intervention to Improve Sleep and Functional Health of Veterans With Insomnia: Randomized Controlled Trial

Background

Insomnia is a prevalent and debilitating disorder among veterans. Cognitive behavioral therapy for insomnia (CBTI) can be effective for treating insomnia, although many cannot access this care. Technology-based solutions and lifestyle changes, such as physical activity (PA), offer affordable and accessible self-management alternatives to in-person CBTI.

Objective

This study aims to extend and replicate prior pilot work to examine whether the use of a mobile app for CBTI (cognitive behavioral therapy for insomnia coach app [CBT-i Coach]) improves subjective and objective sleep outcomes. This study also aims to investigate whether the use of the CBT-i Coach app with adjunctive PA improves sleep outcomes more than CBT-i Coach alone.

Methods

A total of 33 veterans (mean age 37.61 years, SD 9.35 years) reporting chronic insomnia were randomized to use either the CBT-i Coach app alone or the CBT-i Coach app with a PA intervention over 6 weeks, with outcome measures of objective and subjective sleep at pre- and posttreatment.

Results

Although the PA manipulation was unsuccessful, both groups of veterans using the CBT-i Coach app showed significant improvement from baseline to postintervention on insomnia (P<.001), sleep quality (P<.001), and functional sleep outcomes (P=.002). Improvements in subjective sleep outcomes were similar in those with and without posttraumatic stress disorder and mild-to-moderate sleep apnea. We also observed a significant but modest increase in objective sleep efficiency (P=.02).

Conclusions

These findings suggest that the use of a mobile app–delivered CBTI is feasible and beneficial for improving sleep outcomes in veterans with insomnia, including those with comorbid conditions such as posttraumatic stress disorder or mild-to-moderate sleep apnea.

Trial Registration

ClinicalTrials.gov NCT03305354; https://clinicaltrials.gov/ct2/show/NCT03305354

The influence of oxytocin-based interventions on sleep-wake and sleep-related behaviour and neurobiology: A systematic review of preclinical and clinical studies

The oxytocin (OXT) system has garnered considerable interest due to its influence on diverse behaviours. However, scant research has considered the influence of oxytocin on sleep-wake and sleep-related behaviour and neurobiology. Consequently, the objective of this systematic review was to assess the extant preclinical and clinical evidence for the influence of oxytocin-based interventions on sleep-wake outcomes. The primary search was conducted on 22/7/2020 using six electronic databases; 30 studies (19 preclinical, 11 clinical) were included based on inclusion criteria. Studies were evaluated for risk of bias using the SYRCLE tool and the Cochrane risk of bias tools for preclinical and clinical studies, respectively. Results indicated manipulation of the OXT system can influence sleep-wake outcomes. Preclinical evidence suggests a wake-promoting influence of OXT system activation whereas the clinical evidence suggests little or no sleep-promoting influence of OXT. OXT dose was identified as a likely modulatory factor of OXT-induced effects on sleep-wake behaviour. Future studies are necessary to validate and strengthen these tentative conclusions about the influence of OXT on sleep-wake behaviour.

Validation of the Withings Sleep Analyzer, an under-the-mattress device for the detection of moderate-severe sleep apnea syndrome

STUDY OBJECTIVES

To assess the diagnostic performance of a nonintrusive device placed under the mattress to detect sleep apnea syndrome.

METHODS

One hundred eighteen patients suspected to have obstructive sleep apnea syndrome completed a night at a sleep clinic with a simultaneous polysomnography (PSG) and recording with the Withings Sleep Analyzers. PSG nights were scored twice: first as simple polygraphy, then as PSG.

RESULTS

Average (standard deviation) apnea-hypopnea index from PSG was 31.2 events/h (25.0) and 32.8 events/h (29.9) according to the Withings Sleep Analyzers. The mean absolute error was 9.5 events/h. The sensitivity, specificity, and area under the receiver operating characteristic curve at thresholds of apnea-hypopnea index ≥ 15 events/h were, respectively, sensitivity (Se)₁₅ = 88.0%, specificity (Sp)₁₅ = 88.6%, and area under the receiver operating characteristic curve (AUROC) ₁₅ = 0.926. At the threshold of apnea-hypopnea index ≥ 30 events/h, results included Se₃₀ = 86.0%, Sp₃₀ = 91.2%, AUROC₃₀ = 0.954. The average total sleep time from PSG and the Withings Sleep Analyzers was 366.6 (61.2) and 392.4 (67.2) minutes, sleep efficiency was 82.5% (11.6) and 82.6% (11.6), and wake after sleep onset was 62.7 (48.0) and 45.2 (37.3) minutes, respectively.

CONCLUSIONS

Withings Sleep Analyzers accurately detect moderate-severe sleep apnea syndrome in patients suspected of sleep apnea syndrome. This simple and automated approach could be of great clinical value given the high prevalence of sleep apnea syndrome in the general population.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Validation of Withings Sleep for the Detection of Sleep Apnea Syndrome; URL: https://clinicaltrials.gov/ct2/show/NCT04234828; Identifier: NCT04234828.

Preoperative REM sleep is associated with complication development after colorectal surgery

BACKGROUND

While total sleep duration and rapid eye movement (REM) sleep duration have been associated with long-term mortality in non-surgical cohorts, the impact of preoperative sleep on postoperative outcomes has not been well studied.

METHODS

In this secondary analysis of a prospective observational cohort study, patients who recorded at least 1 sleep episode using a consumer wearable device in the 7 days before elective colorectal surgery were included. 30-day postoperative outcomes among those who did and did not receive at least 6 h of total sleep, as well as those who did and did not receive at least 1 h of rapid eye movement (REM) sleep, were compared.

RESULTS

34 out of 95 (35.8%) patients averaged at least 6 h of sleep per night, while 44 out of 82 (53.7%) averaged 1 h or more of REM sleep. Patients who slept less than 6 h had similar postoperative outcomes compared to those who slept 6 h or more. Patients who averaged less than 1 h of REM sleep, compared to those who achieved 1 h or more of REM sleep, had significantly higher rates of complication development (29.0% vs. 9.1%, P = 0.02), and return to the OR (10.5% vs. 0%, P = 0.04). After adjustment for confounding factors, increased REM sleep duration remained significantly associated with decreased complication development (increase in REM sleep from 50 to 60 min: OR 0.72, P = 0.009; REM sleep ≥ 1 h: OR 0.22, P = 0.03).

CONCLUSION

In this cohort of patients undergoing elective colorectal surgery, those who developed a complication within 30 days were less likely to average at least 1 h of REM sleep in the week before surgery than those who did not develop a complication. Preoperative REM sleep duration may represent a risk factor for surgical complications; however additional research is necessary to confirm this relationship.

Discrepancies in the Time Course of Sleep Stage Dynamics, Electroencephalographic Activity and Heart Rate Variability Over Sleep Cycles in the Adaptation Night in Healthy Young Adults

OBJECTIVE

The aim of the present study was to characterize the cyclic sleep processes of sleep-stage dynamics, cortical activity, and heart rate variability during sleep in the adaptation night in healthy young adults.

METHODS

Seventy-four healthy adults participated in polysomnographic recordings on two consecutive nights. Conventional sleep variables were assessed according to standard criteria. Sleep-stage continuity and dynamics were evaluated by sleep runs and transitions, respectively. These variables were compared between the two nights. Electroencephalographic and cardiac activities were subjected to frequency domain analyses. Cycle-by-cycle analysis was performed for the above variables in 34 subjects with four sleep cycles and compared between the two nights.

RESULTS

Conventional sleep variables reflected lower sleep quality in the adaptation night than in the experimental night. Bouts of stage N1 and stage N2 were shorter, and bouts of stage Wake were longer in the adaptation night than in the experimental night, but there was no difference in stage N3 or stage REM. The normalized transition probability from stage N2 to stage N1 was higher and that from stage N2 to N3 was lower in the adaptation night, whereas that from stage N3 to other stages did not differ between the nights. Cycle-by-cycle analysis revealed that sleep-stage distribution and cortical beta EEG power differed between the two nights in the first sleep cycle. However, the HF amplitude of the heart rate variability was lower over the four sleep cycles in the adaptation night than in the experimental night.

CONCLUSION

The results suggest the distinct vulnerability of the autonomic adaptation processes within the central nervous system in young healthy subjects while sleeping in a sleep laboratory for the first time.

Robust, ECG-based detection of Sleep-disordered breathing in large population-based cohorts

STUDY OBJECTIVES

Up to 5% of adults in Western countries have undiagnosed sleep-disordered breathing (SDB). Studies have shown that electrocardiogram (ECG)-based algorithms can identify SDB and may provide alternative screening. Most studies, however, have limited generalizability as they have been conducted using the apnea-ECG database, a small sample database that lacks complex SDB cases.

METHODS

Here, we developed a fully automatic, data-driven algorithm that classifies apnea and hypopnea events based on the ECG using almost 10 000 polysomnographic sleep recordings from two large population-based samples, the Sleep Heart Health Study (SHHS) and the Multi-Ethnic Study of Atherosclerosis (MESA), which contain subjects with a broad range of sleep and cardiovascular diseases (CVDs) to ensure heterogeneity.

RESULTS

Performances on average were sensitivity(Se)=68.7%, precision (Pr)=69.1%, score (F1)=66.6% per subject, and accuracy of correctly classifying apnea-hypopnea index (AHI) severity score was Acc=84.9%. Target AHI and predicted AHI were highly correlated (R2 = 0.828) across subjects, indicating validity in predicting SDB severity. Our algorithm proved to be statistically robust between databases, between different periodic leg movement index (PLMI) severity groups, and for subjects with previous CVD incidents. Further, our algorithm achieved the state-of-the-art performance of Se=87.8%, Sp=91.1%, Acc=89.9% using independent comparisons and Se=90.7%, Sp=95.7%, Acc=93.8% using a transfer learning comparison on the apnea-ECG database.

CONCLUSIONS

Our robust and automatic algorithm constitutes a minimally intrusive and inexpensive screening system for the detection of SDB events using the ECG to alleviate the current problems and costs associated with diagnosing SDB cases and to provide a system capable of identifying undiagnosed SDB cases.

Characterizing Sleep Spindles in Sheep

Sleep spindles are distinctive transient patterns of brain activity that typically occur during non-rapid eye movement (NREM) sleep in humans and other mammals. Thought to be important for the consolidation of learning, they may also be useful for indicating the progression of aging and neurodegenerative diseases. The aim of this study was to characterize sleep spindles in sheep (Ovis aries). We recorded electroencephalographs wirelessly from six sheep over a continuous period containing 2 nights and a day. We detected and characterized spindles using an automated algorithm. We found that sheep sleep spindles fell within the classical range seen in humans (10–16 Hz), but we did not see a further separation into fast and slow bands. Spindles were detected predominantly during NREM sleep. Spindle characteristics (frequency, duration, density, topography) varied between individuals, but were similar within individuals between nights. Spindles that occurred during NREM sleep in daytime were indistinguishable from those found during NREM sleep at night. Surprisingly, we also detected numerous spindle-like events during unequivocal periods of wake during the day. These events were mainly local (detected at single sites), and their characteristics differed from spindles detected during sleep. These “wake spindles” are likely to be events that are commonly categorized as “spontaneous alpha activity” during wake. We speculate that wake and sleep spindles are generated via different mechanisms, and that wake spindles play a role in cognitive processes that occur during the daytime.

Variability and Misclassification of Sleep Apnea Severity Based on Multi-Night Testing

BACKGROUND

Portable monitoring is a convenient means for diagnosing sleep apnea. However, data on whether one night of monitoring is sufficiently precise for the diagnosis of sleep apnea are limited.

RESEARCH QUESTION

The current study sought to determine the variability and misclassification in disease severity over three consecutive nights in a large sample of patients referred for sleep apnea.

METHODS

A sample of 10,340 adults referred for sleep apnea testing was assessed. A self-applied type III monitor was used for three consecutive nights. The apnea-hypopnea index (AHI) was determined for each night, and a reference AHI was computed by using data from all 3 nights. Pairwise correlations and the proportion misclassified regarding disease severity were computed for each of the three AHI values against the reference AHI.

RESULTS

Strong correlations were observed between the AHI from each of the 3 nights (r = 0.87-0.89). However, substantial within-patient variability in the AHI and significant misclassification in sleep apnea severity were observed based on any 1 night of monitoring. Approximately 93% of the patients with a normal study on the first night and 87% of those with severe sleep apnea on the first night were correctly classified compared with the reference derived from all three nights. However, approximately 20% of the patients with mild and moderate sleep apnea on the first night were misdiagnosed either as not having sleep apnea or as having mild disease, respectively.

CONCLUSIONS

In patients with mild to moderate sleep apnea, one night of portable testing can lead to misclassification of disease severity given the substantial night-to-night variability in the AHI.

The wrist is not the brain: Estimation of sleep by clinical and consumer wearable actigraphy devices is impacted by multiple patient- and device-specific factors

Clinical actigraphy devices provide adequate estimates of some sleep measures across large groups. In practice, providers are asked to apply clinical or consumer wearable data to individual patient assessments. Inter-individual variability in device performance will impact such patient-specific interpretation. We assessed two devices, clinical and consumer, to determine the magnitude and predictors of this individual-level variability. One hundred and two patients (55 [53.9%] female; 56.4 [±16.3] years old) undergoing polysomnography wore Jawbone UP3 and/or Actiwatch2. Device total sleep time, sleep efficiency, wake after sleep onset and sleep latency were compared with polysomnography. Demographics, sleep architecture and clinical measures were compared to device performance. Actiwatch overestimated total sleep time by 27.2 min (95% confidence limits [CL], 138.3 min over to 84.0 under), overestimated sleep efficiency by 6.8% (95% CL, 34.1% over to 20.5% under), overestimated sleep onset latency by 2.6 min (95% CL, 63.3 over to 58.2 under) and underestimated wake after sleep onset by 50.7 min (95% CL, 162.5 under to 61.2 over). Jawbone overestimated total sleep time by 59.1 min (95% CL, 208.6 min over to 90.5 under) and overestimated sleep efficiency by 14.9% (95% CL, 52.6% over to 22.7% under). In multivariate models, age, sleep onset latency, wake after sleep onset, % N1 and apnea-hypopnea index explained only some of the variance in device performance. Gender also affected performance. Actiwatch and Jawbone mis-estimate sleep measures with very wide confidence limits and accuracy varies with multiple patient-level characteristics. Given these large individual inaccuracies, data from these devices must be applied only with extreme caution in clinical practice.

Systematic review of the efficacy of commonly prescribed pharmacological treatments for primary treatment of sleep disturbance in patients with diagnosed autoimmune disease

Sleep disturbances are commonly reported by patients with autoimmune disease, and are negatively related to both disease activity and quality of life. Despite the potential for sleep disturbance to exacerbate inflammatory pathways, acute management of sleep disturbance with pharmacological aids is not well understood in this patient group. The objective of this review was to determine the efficacy of pharmacological treatments for sleep disturbance to improve sleep outcomes in adult patients with diagnosed autoimmune disease. Four databases and grey literature were searched for randomized controlled trials which used a pharmacological treatment specifically to treat sleep disturbance in patients with diagnosed autoimmune disease, both in hospitalized and non-hospitalized settings. A sleep outcome was required to be the primary endpoint of the study. Of the 409 studies identified, a total of six were included in the systematic review. Risk of bias across the studies was largely unclear, making an assessment challenging; meta-analysis was not undertaken due to clinical and methodological heterogeneity between studies. While there appeared to be perceived improvement in self-reported sleep quantity and quality in existing studies with pharmacological treatment, there was also evidence of placebo effect on some measures. Relatively small numbers of patients have undergone gold-standard polysomnographic (PSG) recording of sleep which limits our knowledge of objectively determined sleep quantity and quality in patients with autoimmune disease receiving pharmacological treatment for sleep disturbance. Presently there is insufficient evidence to determine whether pharmacological treatment of sleep disturbance is beneficial for improving sleep quantity and quality in this patient group beyond rheumatoid arthritis.

A validation study of a consumer wearable sleep tracker compared to a portable EEG system in naturalistic conditions

OBJECTIVE

To compare a wearable device, the Fitbit Versa (FV), to a validated portable single-channel EEG system across multiple nights in a naturalistic environment.

METHODS

Twenty participants (10 men and 10 women) aged 25-67 years were recruited for the present study. Study duration was 14 days during which participants were asked to wear the FV daily and nightly. The study intended to reproduce free-living conditions; thus, no guidelines for sleep or activity were imposed on the participants. A total of 138 person-nights, equivalent to 76,539 epochs, were used in the validation process. Sleep measures were compared between the FV and portable EEG using Bland-Altman plots, paired t-tests and epoch-by-epoch (EBE) analyses.

RESULTS

The FV showed no significant bias with the EEG for the global sleep measures time in bed (TIB) and total sleep time (TST), and for calculated sleep efficiency (cSE = [TST/TIB] x 100). The FV had 92.1% sensitivity, 54.1% specificity, and 88.5% accuracy with a Cohen's kappa of 0.41, but a prevalence- and bias adjusted kappa of 0.77. The predictive values for sleep (PVS; positive predictive value) and wakefulness (PVW; negative predictive value) were 95.0% and 42.0%, respectively. The FV showed significant bias compared to the portable EEG for time spent in specific sleep stages, for SE as provided by FV, for sleep onset latency, sleep period time, and wake after sleep onset.

CONCLUSIONS

The consumer sleep tracker could be a useful tool for measuring sleep duration in longitudinal epidemiologic naturalistic studies albeit with some limitations in specificity.

Chronic insomnia remitting after maxillomandibular advancement for mild obstructive sleep apnea: a case series

Background

Chronic insomnia and obstructive sleep apnea are both common sleep disorders. Chronic insomnia is thought to result from stress-related physiologic hyperarousal (somatic arousal) that makes it difficult for an individual to fall or stay asleep. Obstructive sleep apnea is thought to result from obstructive respiratory events causing arousals, sleep fragmentation, and recurrent oxygen desaturation. Although the two disorders seem different, they predispose to the same long-term, stress-related illnesses, and when they occur in the same individual, each affects the other’s response to treatment; they interact. This report of three cases describes patients with both chronic insomnia and obstructive sleep apnea in whom the chronic insomnia remitted with no specific treatment following treatment of obstructive sleep apnea with maxillomandibular advancement.

Case presentations

Our three Caucasians patients each presented with severe, chronic insomnia associated with somatic arousal and fatigue occurring either alone, in association with bipolar disorder, or with temporomandibular joint syndrome. Polysomnography revealed that each patient also had mild obstructive sleep apnea, despite only one snoring audibly. One patient experienced a modest improvement in her somatic arousal, insomnia severity, and fatigue with autotitrating nasal continuous positive airway pressure, but the other two did not tolerate nasal continuous positive airway pressure. None of the patients received treatment for insomnia. All three patients subsequently underwent maxillomandibular advancement to treat mild obstructive sleep apnea and experienced prolonged, complete resolution of somatic arousal, chronic insomnia, and fatigue. The patient with bipolar disorder also experienced complete remission of his symptoms of depression during the 1 year he was followed postoperatively.

Conclusions

These three cases lend support to the hypothesis that chronic insomnia and obstructive sleep apnea share a pathophysiology of chronic stress. Among patients with obstructive sleep apnea, the stress response is directed at inspiratory airflow limitation during sleep (hypopnea, snoring, and inaudible fluttering of the throat). Therefore, when chronic insomnia and obstructive sleep apnea occur in one individual, aggressive treatment of obstructive sleep apnea may lead to a reduction in chronic stress that causes the patient’s chronic insomnia to remit.

Mobile App Use for Insomnia Self-Management: Pilot Findings on Sleep Outcomes in Veterans

Background

Sleep disturbance is a major health concern among US veterans who have served since 2001 in a combat theater in Iraq or Afghanistan. We report subjective and objective sleep results from a pilot trial assessing self-management–guided use of a mobile app (CBT-i Coach, which is based on cognitive behavioral therapy for insomnia) as an intervention for insomnia in military veterans.

Objective

The primary aim of this study was to evaluate changes in subjective and objective sleep outcomes from pre to postintervention.

Methods

Subjective outcomes included the Insomnia Severity Index, the Pittsburgh Sleep Quality Inventory, and sleep-related functional status. A wearable sleep monitor (WatchPAT) measured objective sleep outcomes, including sleep efficiency, percent rapid eye movement (REM) during sleep, sleep time, and sleep apnea. A total of 38 participants were enrolled in the study, with 18 participants being withdrawn per the protocol because of moderate or severe sleep apnea and 9 others who dropped out or withdrew. Thus, 11 participants completed the full 6-week CBT-i Coach self-management intervention (ie, completers).

Results

Completer results indicated significant changes in subjective sleep measures, including reduced reports of insomnia (Z=–2.68, P=.007) from pre (mean 16.63, SD 5.55) to postintervention (mean 12.82, SD 3.74), improved sleep quality (Z=–2.37, P=.02) from pre (mean 12.82, SD 4.60) to postintervention (mean 10.73, SD 3.32), and sleep-related functioning (Z=2.675, P=.007) from pre (mean 13.86, SD 3.69) to postintervention (mean 15.379, SD 2.94). Among the objective measures, unexpectedly, objective sleep time significantly decreased from pre to postintervention (χ²₂=7.8, P=.02). There were no significant changes in percent REM sleep or sleep efficiency.

Conclusions

These findings suggest that the CBT-i Coach app can improve subjective sleep and that incorporating objective sleep measures into future, larger clinical trials or clinical practice may yield important information, particularly by detecting previously undetected sleep apnea.

Trial Registration

ClinicalTrials.gov NCT02392000; http://clinicaltrials.gov/ct2/show/NCT02392000

The acute effects of aerobic exercise on sleep in patients with depression: study protocol for a randomized controlled trial

BACKGROUND

Unipolar depression is one of the most important mental disorders. Insomnia is a symptom of cardinal importance in depression. It increases the risk to develop depression, negatively affects disease trajectory, is the most common symptom after remission, increases the risk of relapse, and is associated with higher suicide rates. Existing therapies for insomnia in depression have limitations. Further adjuvant therapies are therefore needed. Acute aerobic exercise has been shown to have beneficial effects on sleep in healthy individuals and patients with insomnia. We therefore hypothesize that a single session of aerobic exercise has a positive impact on sleep in patients with unipolar depression. This trial aims to investigate the effects of a single bout of aerobic exercise on the subsequent night's sleep in patients with depression.

METHODS/DESIGN

This is a two-arm parallel group, randomized, outcome assessor blinded, controlled, superiority trial. Patients between 18 and 65 years of age with a primary diagnosis of unipolar depression (without a psychotic episode) are included. Exclusion criteria are regular use of hypnotic agents, opioids, and certain beta-blockers, as well as the presence of factors precluding exercise, history of epilepsy, restless legs syndrome, moderate obstructive sleep apnea, and a BMI > 40. The intervention is a single bout of aerobic exercise, performed for 30 min on a bicycle ergometer at 80% individual anaerobic threshold. The control group sits and reads for 30 min. The primary outcome is sleep efficiency measured by polysomnography. Secondary outcomes include further polysomnographic variables, subjective pre-sleep arousal, nocturnal cardiovascular autonomic modulation, subjective sleep quality, daytime sleepiness, and adverse events. According to the sample size calculation, a total of 92 patients will be randomized using minimization.

DISCUSSION

This trial will add new information to the body of knowledge concerning the treatment of insomnia in patients with depression. Thereby, the results will inform decision makers on the utility of acute aerobic exercise.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03673397 . Protocol version 1 registered on 17 September 2018.

Validation of a Device for the Ambulatory Monitoring of Sleep Patterns: A Pilot Study on Parkinson's Disease

The development of wearable devices has increase interest in the use of ambulatory methods to detect sleep disorders more objectively than those permitted by subjective scales evaluating sleep quality, while subjects maintain their usual lifestyle. This study aims to validate an ambulatory circadian monitoring (ACM) device for the detection of sleep and wake states and apply it to the evaluation of sleep quality in patients with Parkinson disease (PD). A polysomnographic validation study was conducted on a group of patients with different sleep disorders in a preliminary phase, followed by a pilot study to apply this methodology to PD patients. The ACM device makes it possible to estimate the main sleep parameters very accurately, as demonstrated by: (a) the lack of significant differences between the mean values detected by PSG and ACM in time in bed (TIB), total sleep time (TST), sleep efficiency (SE), and time awake after sleep onset (WASO); (b) the slope of the correlation lines between the parameters estimated by the two procedures, very close to 1, which demonstrates the linearity of the predictions; (c) the low bias value in the estimates obtained through ACM. Sleep in PD is associated with lower distal skin temperature, efficiency and overall sleep time; greater WASO, activity during sleep and duration of naps and a worse circadian function index. In summary, the ACM device has proven to be clinically useful to evaluate sleep in an objective manner, thanks to the integrated management of different complementary variables, having advantages over conventional actigraphy.

Effects of a Workplace-Based Sleep Health Program on Sleep in Members of the German Armed Forces

STUDY OBJECTIVES

To develop and evaluate a brief manual-based sleep health program within the workplace health promotion of the German Armed Forces.

METHODS

The sleep health program comprised four weekly group sessions. Sixty-three members (48 males) were randomly allocated to either a treatment group or a waiting control group matching for age, sex, and baseline Pittsburgh Sleep Quality Index (PSQI). The control group had to wait before participating in the sleep health program until the treatment group finished the intervention. Sleep was assessed by ambulatory polysomnography (PSG) as well as with evening and morning protocols at baseline (t0), directly after the treatment group participated in the sleep health program (t1), and after the control group finished participation (t2). The PSQI, the Insomnia Severity Index (ISI), and the Epworth Sleepiness Scale (ESS) were applied at the same three time points, and during a 3-month follow-up evaluation (t3).

RESULTS

Fifty-seven out of the 63 randomized individuals (42 males, mean age = 40.6 years; complete PSG data: n = 36; complete questionnaire data: n = 39) participated in the sleep health program. Objective wake after sleep onset, sleep efficiency, latency to persistent sleep, self-reported sleep latency, restfulness, PSQI, and ISI scores improved with medium or large effects in both groups. ESS scores decreased with moderate effects in the treatment group only.

CONCLUSIONS

The sleep health program had a positive and stable effect on objective and self-reported sleep parameters, and it is suitable as a preventive measure in members of the German Armed Forces.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: Development and Evaluation of a Sleep-coaching Program; Identifier: NCT02896062; URL: https://clinicaltrials.gov/ct2/show/record/NCT02896062.

Association of Short Sleep Duration and Atrial Fibrillation

BACKGROUND

Short sleep may be a risk factor for atrial fibrillation. However, previous investigations have been limited by lack of objective sleep measurement and small sample size. We sought to determine the association between objectively measured sleep duration and atrial fibrillation.

METHODS

All 31,079 adult patients undergoing diagnostic polysomnography from 1999 to 2015 at multiple sites within a large hospital network were identified from electronic medical records. Prevalent atrial fibrillation was identified by continuous ECG during polysomnography. Incident atrial fibrillation was identified by diagnostic codes and 12-lead ECGs. Logistic regression and Cox proportional hazards modeling were used to examine the association of sleep duration and atrial fibrillation prevalence and incidence, respectively, adjusting for age, sex, BMI, hypertension, coronary artery disease, cerebrovascular disease, peripheral vascular disease, heart failure, and sleep apnea severity.

RESULTS

We identified 404 cases of prevalent atrial fibrillation among 30,061 individuals (mean age ± SD, 51.0 ± 14.5 years; 51.6% women) undergoing polysomnography. After adjustment, each 1-h reduction in sleep duration was associated with a 1.17-fold (95% CI, 1.11-1.30) increased risk of prevalent atrial fibrillation. Among 27,589 patients without atrial fibrillation at baseline, we identified 1,820 cases of incident atrial fibrillation over 4.6 years median follow-up. After adjustment, each 1-h reduction in sleep duration was associated with a 1.09-fold (95% CI, 1.05-1.13) increased risk for incident atrial fibrillation.

CONCLUSIONS

Short sleep duration is independently associated with prevalent and incident atrial fibrillation. Further research is needed to determine whether interventions to extend sleep can lower atrial fibrillation risk.

The Benefits of Closed-Loop Transcranial Alternating Current Stimulation on Subjective Sleep Quality

Background: Poor sleep quality is a common complaint, affecting over one third of people in the United States. While sleep quality is thought to be related to slow-wave sleep (SWS), there has been little investigation to address whether modulating slow-wave oscillations (SWOs) that characterize SWS could impact sleep quality. Here we examined whether closed-loop transcranial alternating current stimulation (CL-tACS) applied during sleep impacts sleep quality and efficiency. Methods: CL-tACS was used in 21 participants delivered at the same frequency and in phase with endogenous SWOs during sleep. Sleep quality was assessed in the morning following either verum or sham control stimulation during sleep, with order counterbalanced within participants. Results: Higher sleep quality and efficiency were found after verum stimulation nights compared to control. The largest effects on sleep quality were found immediately following an adaptation night in the laboratory for which sleep quality was reduced. Conclusions: Applying CL-tACS at the same frequency and phase as endogenous SWOs may offer a novel method to improve subjective sleep quality after a night with poor quality sleep. CL-tACS might be helpful for increasing sleep quality and efficiency in otherwise healthy people, and in patients with clinical disorders that involve sleep deficits.

Role of the IL-6-Receptor expression in CD14+ monocytes in modulating sleep in patients with bipolar disorder

OBJECTIVE

Bipolar disorder is a severe mental disorder associated with persistent sleep disturbances and elevated levels of mRNA coding for pro-inflammatory cytokines within peripheral monocytes. The mechanisms causing and sustaining a reduced sleep quality remain elusive. The pro-inflammatory cytokine receptor IL-6R is known to negatively affect sleep quality and architecture. Since elevations in IL-6R have repeatedly been demonstrated in bipolar disorder the association of sleep quality and architecture with levels of mRNA coding for IL-6R in monocytes was to be tested.

METHODS

Euthymic patients with bipolar disorder (n = 24) and healthy control subjects (n = 25) were assessed using all night polysomnography (PSG) and six day actigraphy. CD14+ monocytes were isolated on the evening of PSG assessment and levels of mRNA coding for IL-6R and other cytokines were determined using hybridization based assays. Interactions between IL-6R and sleep measures were calculated using linear regression models, adjusting for potential confounders.

RESULTS

Patients with bipolar disorder were found to have a reduced subjective sleep quality as assessed by the Pittsburgh Sleep Quality Index (PSQI) and more frequent arousals and short changes to wake during sleep. Both PSQI and the frequency of arousals were significantly predicted by levels of IL-6R. Contrary to previous publications, elevated levels of mRNA coding for pro-inflammatory cytokines in peripheral CD14+ monocytes of patients with bipolar disorder could not be replicated.

LIMITATIONS

Participants were only investigated with one night of PSG which may have given rise to first night effects.

CONCLUSIONS

Reduced sleep quality in euthymic patients with bipolar disorder may be related to an increased expression of IL-6R by peripheral monocytes.

Increased prevalence of obstructive sleep apnea in patients with pectus excavatum: A pilot study

Objective:

Laryngomalacia is the most common congenital laryngeal anomaly and is associated with pectus excavatum (PE). Patients with laryngomalacia and patients with obstructive sleep apnea (OSA) both experience upper airway obstruction, and patients with laryngomalacia had been found to have a higher prevalence of PE. However, no studies have established the prevalence of OSA in patients with PE. We conducted this pilot study to evaluate the prevalence of OSA in patients with PE.

Materials and Methods:

A total of 42 patients ≥20 years old with PE who were admitted for Nuss surgery to correct PE in Taipei Tzu Chi Hospital between October 2015 and September 2016 were invited to participate in the study; 31 of the 42 patients agreed. All 31 patients completed an Epworth sleepiness scale questionnaire to evaluate excessive daytime sleepiness (EDS) and underwent overnight polysomnography to evaluate OSA before Nuss surgery.

Results:

The prevalence of snoring in the study participants was 100%. Ten of 31 patients (32.3%) reported EDS. The overall prevalence of OSA with an apnea/hypopnea index ≥5/h was 25.8%, and all patients with OSA were men.

Conclusions:

The prevalence of OSA in patients with PE seemed to be higher than that previously reported in the general population, implying that OSA might be a potential etiology or, at least, an aggravating factor for the development or progression of PE or might be responsible for the postoperative recurrence of PE in some patients. Further studies are needed to clarify this relationship.

All-night functional magnetic resonance imaging sleep studies

BACKGROUND

Previous functional magnetic resonance imaging (fMRI) sleep studies have been hampered by the difficulty of obtaining extended amounts of sleep in the sleep-adverse environment of the scanner and often have resorted to manipulations such as sleep depriving subjects before scanning. These manipulations limit the generalizability of the results.

NEW METHOD

The current study is a methodological validation of procedures aimed at obtaining all-night fMRI data in sleeping subjects with minimal exposure to experimentally induced sleep deprivation. Specifically, subjects slept in the scanner on two consecutive nights, allowing the first night to serve as an adaptation night.

RESULTS/COMPARISON WITH EXISTING METHOD(S)

Sleep scoring results from simultaneously acquired electroencephalography data on Night 2 indicate that subjects (n = 12) reached the full spectrum of sleep stages including slow-wave (M = 52.1 min, SD = 26.5 min) and rapid eye movement (REM, M = 45.2 min, SD = 27.9 min) sleep and exhibited a mean of 2.1 (SD = 1.1) nonREM-REM sleep cycles.

CONCLUSIONS

It was found that by diligently applying fundamental principles and methodologies of sleep and neuroimaging science, performing all-night fMRI sleep studies is feasible. However, because the two nights of the study were performed consecutively, some sleep deprivation from Night 1 as a cause of the Night 2 results is likely, so consideration should be given to replicating the current study with a washout period. It is envisioned that other laboratories can adopt the core features of this protocol to obtain similar results.

First-Night Effect on Sleep in Different Female Reproductive States

OBJECTIVES

In sleep laboratory studies, the new environment is generally considered to disturb sleep during the first night. However, older women have rarely been studied. Although menopause and hormone therapy affect sleep, their impact on the first-night effect is virtually unknown.

PARTICIPANTS

Four groups of women with no sleep laboratory experience: young on hormonal contraceptives (n = 11, 23.1 [0.5] years), perimenopausal (n = 15, 48.0 [0.4] years), postmenopausal without hormone therapy (HT; off-HT, n = 22, 63.4 [0.8] years) and postmenopausal with HT (n = 16, 63.1 [0.9] years).

PROCEDURE

A cross-sectional study.

METHODS

Polysomnography was performed over two consecutive nights and the first-night effect and group differences were evaluated. Questionnaire-based insomnia and sleepiness scores were correlated to sleep variables and their between-night changes.

RESULTS

Although sleep in young women was deeper and less fragmented than in the other groups, first-night effect was similar in all study groups. Total sleep time, sleep efficiency, and S1 and S2 sleep increased, and wake after sleep onset, awakenings per hour of sleep, S2 and REM latencies, and percentage of SWS decreased from the first to the second night. Perimenopausal women had more insomnia complaints than other women. Insomnia complaints were associated with more disturbed sleep but not with the first-night effect.

CONCLUSIONS

A first night in a sleep laboratory elicits a marked interference of sleep architecture in women of all ages, with a carryover effect of lighter sleep on the second study night. Menopausal state, HT use, or insomnia complaints do not modify this effect.

Home Polysomnography Reveals a First-Night Effect in Patients With Low Sleep Bruxism Activity

STUDY OBJECTIVES

To examine the presence of a first-night effect (FNE) and the level of internight variability in sleep bruxism (SB) activity when a self-applicable electrode set is used in home polysomnography (PSG) in a sample of subjects with possible SB.

METHODS

Fourteen females and two males aged 38.3 ± 9.1 years (mean ± standard deviation) with self-reported SB underwent home-PSG on three consecutive nights. The subjects applied PSG sensors themselves, including self-applicable electrode sets used to record sleep and masseter muscle activity. Repeated-measures analysis of variance was used to compare SB and sleep variables between the nights.

RESULTS

Surprisingly, there were statistically significant elevations in the rhythmic masticatory muscle activity (RMMA) episode index (P = .009), burst index (P = .016), and bruxism time index (P = .049) throughout the course of 3 nights. More bruxers were diagnosed on the second (6 bruxers, ≥ 2 episodes/h) and third night (7 bruxers) compared to the first night (2 bruxers). Most subjects (14/16) had their highest RMMA index on the second or third night. The mean coefficient of variation for RMMA episode index was 50.7%. No statistically significant differences were detected in other sleep variables.

CONCLUSIONS

The results indicate that a FNE may be present in SB activity, possibly lasting several nights in some subjects. Furthermore, FNE appears to be combined with high internight variability of SB activity without indications of internight changes in sleep macrostructure. To confirm the level of ongoing SB activity, several nights of PSG may be required, especially in subjects with low first-night SB activity.

COMMENTARY

A commentary on this article appears in this issue on page 1281.

Joint effects of OSA and self-reported sleepiness on incident CHD and stroke

BACKGROUND

Although excessive daytime sleepiness (EDS) is a common symptom of obstructive sleep apnea (OSA), and both EDS and OSA have separately been associated with increased risk of cardiovascular disease (CVD), their joint association with CVD risk is unknown.

METHODS

Among 3874 Sleep Heart Health Study (SHHS) participants without prevalent CVD, moderate to severe OSA was defined by an apnea hypopnea index (AHI) ≥ 15 on an in-home polysomnography. EDS was defined as an Epworth Sleepiness Scale score ≥11. Incident CVD events included total CVD events (coronary heart disease (CHD) and stroke), as well as CHD and stroke separately. Cox proportional hazards models adjusted for age, sex, alcohol, smoking, and body mass index.

RESULTS

Compared to those with AHI <15, the hazard ratios (95% CI) for the association of moderate-severe OSA (AHI ≥15) were as follows: CVD 1.06 (0.85-1.33); CHD 1.08 (0.85-1.33); and stroke 1.18 (0.75-1.84). Weak associations between EDS and CVD risk = [1.22 (1.01-1.47)] and CHD risk [1.25 (1.02-1.53)] were present, however there were none for stroke risk [1.10 (0.75-1.63)]. When jointly modeled, both AHI ≥15 and EDS (compared with having AHI <15 and no EDS) was associated with HRs of 1.26 (0.91-1.73) for CVD, 1.24 (0.87-1.75) for CHD and 1.49 (0.78-2.86) for stroke. There were no statistically significant interactions between daytime sleepiness and OSA on the multiplicative or additive scales.

CONCLUSIONS

Having both EDS and moderate-severe OSA was not associated with an increased risk of CVD in the SHHS data.

Anticipated next-day demand affects the magnitude of the cortisol awakening response, but not subjective or objective sleep

Whilst the association between sleep and stress is well established, few studies have examined the effects of an anticipated stressor upon sleep and relevant physiological markers. The aim of the present study was to examine whether an anticipated stressor in the form of next-day demand affects subjective and objective sleep, and multiple indices of the cortisol awakening response. Subjective and objective sleep and the cortisol awakening response were measured over three consecutive nights in 40 healthy adults in a sleep laboratory. During their second night, participants were informed that they would either be required to complete a series of demanding cognitive tasks, in a competition format, during the next day (anticipation condition; n = 22), or were given no instruction (sedentary condition; n = 18). Sleep was measured subjectively using sleep diaries, objectively using polysomnography, and saliva was measured at awakening, +15, +30, +45 and +60 min each morning, from which cortisol awakening response measurement indices were derived: awakening cortisol levels, the mean increase in cortisol levels and total cortisol secretion. There were no between-group differences in subjective or objective sleep in the night preceding the anticipated demand; however, compared with the sedentary condition, those in the anticipation group displayed a larger mean increase in cortisol levels, representing the cortisol awakening response magnitude, on the morning of the anticipated demand. Overall, the results suggest that whilst anticipated stress affected the subsequent cortisol awakening response, subjective and objective sleep remained undisturbed. It is possible that the timing of an anticipated stressor, rather than its expected duration, may influence subsequent sleep disruption.

Associations of sedentary time and moderate-vigorous physical activity with sleep-disordered breathing and polysomnographic sleep in community-dwelling adults

PURPOSE

The purpose of this study was to evaluate the relationship between daytime activity (sedentary time, moderate- to vigorous-intensity physical activity [MVPA]) and indices of polysomnographically (PSG) assessed sleep, including sleep-disordered breathing (SDB).

METHODS

One hundred and thirty-six adults (65% female, 59.8 ± 9.1 years, body mass index [BMI] 30.3 ± 6.9 kg m-2) provided daily estimates of time spent in light-, moderate-, and vigorous-intensity activity for 6-14 days (mean 9.9 ± 1.8 days) prior to laboratory PSG. Daily sedentary time was calculated as the amount of time spent awake and not in light-, moderate-, or vigorous-intensity activity; time spent in moderate- and vigorous-intensity activity were combined for MVPA. Indices of PSG sleep included timing (sleep midpoint), duration (total sleep time), continuity (sleep efficiency), depth (% slow-wave sleep), and SDB (apnea-hypopnea index [AHI]). Using median splits of sedentary time and MVPA, analyses of covariance examined their relationship with sleep following adjustment for age, sex, race, employment, education, BMI, existing cardiovascular disease, depression history, and mean daily wake time. Binary logistic regression examined the odds of having at least mild-severity SDB (AHI ≥ 5) according to sedentary time, MVPA, and their combination.

RESULTS

Adults with above-median sedentary time (i.e., >841.9 min/day) had significantly greater AHI (P = .04) and lower odds of mild SDB (P = .03) compared to adults with low sedentary time; adults with high MVPA (>30.5 min/day) had significantly lower AHI compared to adults with low MVPA (P = .04). When examined in the same model, adults with high sedentary time and low MVPA had significantly higher AHI (P < .01) and higher odds of having mild SDB (P = .03) than all the other groups. No other sleep measures were related to sedentary time, MVPA, or their combination.

CONCLUSIONS

Sedentary time and MVPA were associated with SDB. Whether reducing sedentary time leads to lower SDB severity deserves future exploration.

Oral appliance therapy versus nasal continuous positive airway pressure in obstructive sleep apnoea syndrome: a randomised, placebo-controlled trial on self-reported symptoms of common sleep disorders and sleep-related problems

Obstructive sleep apnoea syndrome (OSAS) is associated with several sleep disorders and sleep-related problems. Therefore, the aim of this study was to compare the effects of a mandibular advancement device (MAD) with those of nasal continuous positive airway pressure (nCPAP) on self-reported symptoms of common sleep disorders and sleep-related problems in mild and moderate OSAS patients. In this randomised placebo-controlled trial, sixty-four OSAS patients (52·0 ± 9·6 years) were randomly assigned to an MAD, nCPAP or an intra-oral placebo appliance in a parallel design. All participants filled out the validated Dutch Sleep Disorders Questionnaire (SDQ) twice: one before treatment and one after six months of treatment. With 88 questions, thirteen scales were constructed, representing common sleep disorders and sleep-related problems. Linear mixed model analyses were performed to study differences between the groups for the different SDQ scales over time. The MAD group showed significant improvements over time in symptoms corresponding with 'insomnia', 'excessive daytime sleepiness', 'psychiatric sleep disorder', 'periodic limb movements', 'sleep apnoea', 'sleep paralysis', 'daytime dysfunction', 'hypnagogic hallucinations/dreaming', 'restless sleep', 'negative conditioning' and 'automatic behaviour' (range of P values: 0·000-0·014). These improvements in symptoms were, however, not significantly different from the improvements in symptoms observed in the nCPAP and placebo groups (range of P values: 0·090-0·897). It can be concluded that there is no significant difference between MAD and nCPAP in their positive effects on self-reported symptoms of common sleep disorders and sleep-related problems in mild and moderate OSAS patients. These beneficial effects may be a result of placebo effects.

Effects of Short-Term Acclimatization at the Summit of Mt. Fuji (3776 m) on Sleep Efficacy, Cardiovascular Responses, and Ventilatory Responses

Horiuchi, Masahiro, Shiro Oda, Tadashi Uno, Junko Endo, Yoko Handa, and Yoshiyuki Fukuoka. Effects of short-term acclimatization at the summit of Mt. Fuji (3776 m) on sleep efficacy, cardiovascular responses, and ventilatory responses. High Alt Med Biol. 18:171-178, 2017.-We investigated the effects of a short period of acclimatization, at 3776 m on Mt. Fuji, on sleep parameters and related physiological responses. Physiological responses were assessed in seven healthy lowlander men during both daytime and sleep while at sea level (SL), as well as for three consecutive nights at high altitude (HA; 3776 m, day 1 [D1], D2, D3, and morning only of D4). Blood pressure variables, heart rate (HR), pulmonary ventilation (V_E), and breathing frequency (Bf) progressively increased each day, with significant differences between SL and HA (p < 0.05, respectively). In contrast, end-tidal PCO₂ (P_ETCO₂) progressively decreased each day with statistical differences between SL and D3 at HA (p < 0.05). During sleep at HA, mean arterial pressure (MAP) was stable, whereas it decreased during sleep at SL. Sleep efficacy, which was assessed by actigraphy, was linearly impaired with statistical differences between SL and D3 (p < 0.05). These impairments in sleep efficacy at HA were associated with higher MAP and HR, as well as lower Bf and P_ETCO₂ during the daytime (pooled data, p < 0.05, respectively). These results suggest that hypoxia-induced cardiovascular and ventilatory responses may be crucial contributors to changes in sleep efficacy at HA.