Journal of Sleep Research最新文献

Preterm birth is a significant risk factor for atypical neurodevelopment, yet early electrophysiological markers of brain maturation are still lacking. Non-invasive electroencephalographic (EEG) monitoring of cortical maturation in these patients holds promise as a tool for neurodevelopmental prediction. However, its clinical application is limited by technical challenges in maintaining stable, long-term electrode placement on very small neonate scalps and by the highly specialised, multi-level expertise required to care for these fragile patients. Using video-polysomnographic EEG recordings in very low birth weight (VLBW, < 1500 g) preterm infants, we characterised large-scale neuronal dynamics during distinct vigilance states and tested whether they could serve as indicators of early cortical maturation. We analysed EEG recordings obtained at 33.9 ± 1.4 weeks postmenstrual age (PMA), during active sleep (AS), sleep onset active sleep (SOAS), quiet sleep (QS), and quiet wakefulness (QW). For each vigilance state, we assessed large-scale neuronal dynamics in terms of phase synchronisation, neuronal bistability, and local phase-amplitude coupling (PAC), both globally and separately for anterior and posterior regions, and correlated them with PMA. We found that phase synchronisation peaked in the δ band during QS and in the θ band during more active states (QW, SOAS, AS). δ-band bistability was lower in posterior regions across all states, while δ-PAC was lower posteriorly during sleep but reversed during wakefulness. Also, bistability and PAC decreased with advancing PMA. These findings suggest that vigilance-state-dependent neuronal dynamics capture aspects of early cortical maturation-even with low-density EEG cap-offering novel candidate biomarkers to monitor neurodevelopment in infants born preterm.

Declarative memories are reactivated-and thereby consolidated-during sleep. Real-life memories are typically nested hierarchically (e.g., memory for making coffee nested within memory for one's morning routine). We tested the specificity of memory reactivation during sleep in humans: is it limited to low-tier items or does it extend to wider contexts? To test this, we adapted a well-replicated design using targeted memory reactivation, which uses non-invasive sensory cues to preferentially reactivate memories during sleep. Thirty-two participants (18 women and 14 men) learned two sets of object locations, each paired with a unique odour. By cueing one odour during non-REM sleep, we tested whether reactivation would benefit the entire learning context or selectively enhance the cued set. Our results show no overall benefit for the cued set over the non-cued one. A more nuanced, encoding-strength-dependent reactivation effect was observed for the cued category relative to the non-cued one. Whereas previous studies showed that odour presentation increased spectral activity in the sigma range, putatively reflecting sleep spindles, we found a sustained (~15 s) inhibition following presentation. The results indicate that cueing did not uniformly benefit the targeted memories. One explanation for these results is that cueing benefits may have generalised across the learning context as a whole rather than impacting a single set of memories. Moreover, our results provide more evidence that initial encoding strength dictates the extent of reactivation effectiveness.

Adolescents frequently use smartphones, smartwatches, personal computers, tablets, and other electronic devices during the day and at night. Whilst these devices are kept close to the eyes, they emit artificial light at night (ALAN) and generate noise. ALAN and noise are also emitted from other indoor and outdoor sources, such as home appliances, road traffic, street lighting, and advertising boards. However, the effect of these exposures has been studied mainly in the adult population, and little is known about their combined effect on adolescents. The present study aims to bridge this knowledge gap by examining the combined effect of ALAN and noise on the quality of sleep of junior high and high school students. Study participants included 81 adolescents (age 13-18 years) living in Tamra, a town in northern Israel. A 41-day experiment was carried out during which participants wore smartwatches, connected to Android smartphones, to monitor their exposures to ALAN and noise and their sleep patterns. The collected data were then analysed using statistical tools and showed that an increase in ALAN in a plausible range of 40-150 lx before sleep is estimated to reduce sleep efficiency (SE), all other factors being constant, by ~18% (t < -16, p < 0.01), whilst an increase in noise from 30 to 60 dB was estimated to reduce SE by ~22% (t < -14, p < 0.01). These estimates are higher than those found for the adult population in previous studies, according to which the effects of these environmental risk factors on sleep duration and quality were estimated to be ~8%-9%.

This study aimed to assess caregivers' awareness, use and acceptability of common infant behavioural sleep strategies/interventions and explore differences in awareness and acceptability based on country of residence. A cross-sectional online survey was conducted with caregivers (n = 914) of infants aged between 6 and 18 months residing in Australia, Canada, Turkey, the United Kingdom and the United States. Caregivers were provided descriptions of common infant behavioural sleep interventions and reported their awareness of, use, and level of acceptability (using a validated measure: the acceptability of intervention measure [AIM]) for each intervention. Awareness of interventions ranged from 50% to 70% of caregivers, with significant variability by country. Overall, 70% of caregivers had used at least one intervention, with usage rates varying from 25% to 80% depending on the intervention and 30% to 55% of caregivers ceasing use prematurely. Unmodified extinction (AIM = 2.12; 5 = high acceptability), parental presence (AIM = 2.75) and modified extinction (AIM = 2.85) had lower levels of acceptability compared to responsive settling with gradual reduction (AIM = 3.48) and response-based with settling in arms (AIM = 3.51) and bed (AIM = 3.23). Significant differences in acceptability (AIM) scores by country were evident for most of the interventions. As none of the interventions were universally acceptable, a model of care that provides caregivers with information about a range of interventions and the opportunity to choose based on their preferences, parenting styles and cultural beliefs may increase the likelihood of successful intervention adoption.

We examined the urinary metabolome of those with obstructive sleep apnoea hypopnoea syndrome (OSAHS), and how continuous positive airway pressure (CPAP) affects it. We compared it with their non-OSAHS counterparts to identify any distinguishing biomarkers that could be used to diagnose and monitor, as well as highlight those at increased cardiometabolic risk. Observational, prospective and longitudinal study including 70 consecutive attenders referred to our sleep service. OSAHS was defined as apnoea-hypopnoea index ≥ 15 events/h and Epworth sleepiness score (ESS) > 10. Patients treated with CPAP were followed up 6-10 weeks following treatment set-up. Untargeted urinary metabolomic profiling was performed using high-throughput flow-infusion electrospray high-resolution mass spectrometry (FIE-MS). A panel of metabolites was identified (mainly glycerophospholipids, acylcarnitines and fatty acids), with a single metabolite, octadecanamide, being able to differentiate between OSAHS and non-OSAHS with an accuracy (95% CI) of 0.86 [0.76-0.93]. Levels of the panel of metabolites were significantly lower with CPAP, with the effect on 2-anilino-6-cyclohexylmethoxypurine (a hypoxanthine) being particularly marked (AUC 0.93 [0.858-0.971]). Metabolomics in urine offers a promising and non-invasive way to differentiate and diagnose OSAHS from non-OSAHS, while identifying pathways activated by chronic intermittent hypoxia, oxidative stress and inflammation. Correlation of these key metabolites with the known cardiometabolic consequences of OSAHS could potentially highlight those at an increased risk of adverse complications and provide areas for future personalised targeted treatments that CPAP is unable to impact currently, whilst also being a surrogate marker of treatment compliance.

For athletes in endurance sports, who compete over several days and in unpredictable conditions, managing sleep-wake rhythms is critical to ensure optimal performance and minimise the risks to safety. Despite its growing popularity, the role of sleep management on ultracycling performance has received little attention. We analysed the sleep strategies of ultracyclists to better understand (1) how sleep strategies and durations are related to race time and (2) how sleep debt and circadian timing are related to subjective sleepiness and cognitive performance. Twenty-three cyclists completed the study. To track cyclists' sleep, participants wore a wrist-worn accelerometer throughout a long-distance endurance cycling competition. From before the race start until the end, participants rated their sleepiness every 4 h. They also completed a cognitive task at basecamp on five occasions (before start, 620 km, 1438 km, 2066 km and after crossing the finish line). We observed that participants with higher mean sleep times per 24 h finished with higher race rankings. Perceived sleepiness was greater for those who slept less than 5.29 h per day on average, showing a distinct 24 h rhythm. In addition, cognitive performance was worse and response times were slower for those who slept less across days. The findings from this study demonstrate that sleep duration and timing are imperative for preserving physical and cognitive well-being during ultracycling races. Adopting sleep timing strategies, particularly ones that align sleep with homeostatic and circadian drives for sleep, may improve athletes' ultracycling performance.

Obstructive sleep apnea (OSA) has numerous complications that negatively impact patients' quality of life. Early diagnosis can significantly reduce these complications. The aim of the study was to evaluate the relationship between the hyoid bone position and the severity of apnea, and to determine if hyoid-related cephalometric variables can be used as predictors of apnea severity. A systematic review of the literature was conducted following PRISMA guidelines. The search was conducted across databases including Medline, ScienceDirect, BVS, and WOK. Two researchers analysed the results applying inclusion and exclusion criteria, with a third researcher resolving discrepancies. After screening, a total of 22 articles were selected for qualitative review. The risk of bias and quality of the studies was assessed using the Downs and Black checklist. Among the 22 selected articles, 9% were classified as poor quality, 46% as fair, and 45% as good quality. A positive correlation was observed between a lower hyoid bone position and the apnea-hypopnea index (AHI), indicating that a lower hyoid position is associated with a higher AHI. The H-MP variable (distance between point H and the mandibular plane) presented the strongest predictive power for OSA severity. However, insufficient evidence was found to establish an association between the anteroposterior position of the hyoid bone and OSA severity. The severity of obstructive sleep apnea (OSA) is associated with a lower position of the hyoid bone, as reflected in the positive correlation between H-MP and the apnea-hypopnea index (AHI), while the sagittal position showed no significant relevance.

Obstructive sleep apnea (OSA) affects around 936 million individuals worldwide, making it the most prevalent breathing-related sleep disorder. The aim was to estimate the prevalence of OSA in São Paulo, Brazil, based on data from the São Paulo Epidemiologic Sleep Study (EPISONO) 4th edition. This was a cross-sectional study with a probabilistic sample obtained through a 4-stage cluster sampling method aiming to represent the population according to age (20-80 years), gender and socio-economic condition. Participants underwent in-lab full-night polysomnography and completed sleep-related questionnaires. The diagnosis of OSA followed the most recent guidelines of the American Academy of Sleep Medicine. Prevalences were calculated and a multivariable logistic regression evaluated risk factors associated with OSA. The total sample included 769 individuals (452 women). The general adjusted prevalence of OSA was 37.12%, being higher in men (44.88%) than women (30.79%). Greater prevalence was observed in advanced age groups. Moderate and severe OSA affected 11.5% and 7.9% of the participants, respectively. Ageing, body mass index and being male were associated with a higher risk of OSA, especially in moderate-to-severe cases. The 4th edition of EPISONO found that more than one-third of the population had OSA, reaching 45% in males. These results underscore the need for public health actions based on scalable prevention strategies and equitable access to OSA therapies.

Several data suggested a possible role of inflammatory factors in restless legs syndrome (RLS). In this regard, the results of a limited number of studies assessing serum or plasma levels of cytokines have been inconclusive. To investigate the possible role of several cytokines (tumour necrosis factor α-TNF-α, and interleukins-IL-1α, IL-1β, IL-6 and IL-10) as markers of idiopathic RLS (iRLS), we have measured their serum levels in a large series of iRLS patients and controls. We assessed serum levels of TNF-α, IL-1α, IL-1β, IL-6 and IL-10 in 100 patients diagnosed with iRLS and 110 age- and sex-matched healthy controls using a monoclonal Enzyme-Linked ImmunoSorbent Assay (ELISA) method. Serum levels of IL-1α and IL-1β were below detection limits both in iRLS patients and controls. Serum TNF-α, IL-6 and IL-10 levels did not differ significantly between iRLS patients and controls in the whole series, although TNF-α levels were lower in male iRLS patients compared with male iRLS controls. Serum TNF-α, IL-6 and IL-10 levels were not correlated with age at onset and severity of RLS. The data from the current study suggest that serum levels of the cytokines studied cannot be considered useful markers of iRLS.

Sleep bruxism (SB) has been reportedly associated with temporomandibular disorder (TMD); however, solid evidence is lacking. Previous studies have primarily used traditional metrics, such as the masticatory muscle activity (MMA) index and bruxism time index (BTI) to investigate the link between SB and TMD. However, we aimed to examine how the electromyography (EMG) frequency spectrum is associated with TMD in SB participants. We hypothesised that the EMG signal frequencies during MMA events would be lower in SB participants with TMD pain compared to those without TMD pain. In this exploratory study, we retrospectively analysed home polysomnography data from 44 participants who indicated possible SB. The median signal frequencies and absolute power were calculated using the Fast Fourier Transform of the EMG signals during MMA events. Moreover, the MMA index and BTI were calculated, and all parameters were compared between SB participants with and without TMD pain. The results showed that the absolute power and median frequencies were significantly lower in SB participants with TMD pain compared to those without TMD pain (p < 0.05), whereas the MMA index and BTI did not differ between the groups (p > 0.05). These findings suggest that masticatory muscles are getting fatigued in TMD participants with SB and therefore, EMG frequency-based analysis may provide a promising direction for future assessment of TMD consequences of SB. However, these preliminary results should be validated in future studies involving a larger and more heterogeneous pool of participants.