Sleep advances : a journal of the Sleep Research Society最新文献

Study objectives: Sleep spindles are potential biomarkers for memory decline in aging. However, significant within-person variability in spindle attributes complicates their utility in predicting cognitive deterioration. This study aimed to uncover distinct spindle types and their relevance to memory decline using exploratory, data-driven clustering.

Methods: Polysomnography was collected from younger (n = 43, ages 20-45 years) and older cognitively healthy adults (n = 34, ages 60-81 years). Clustering analysis was performed using multiple features and spatiotemporal context, irrespective of participant age.

Results: Resulting clusters were hierarchically defined by the sleep stage, slow oscillation concurrence, and hemisphere. Stage N3 spindles (15%; predominantly coinciding with slow oscillations) formed a distinct group, followed by N2 spindles coinciding with slow oscillations (27%). Remaining N2 spindles were categorized into unilateral (41%) and bilateral clusters (17%). In older adults, there was a lower proportion of N2 bilateral spindles and a higher proportion of N2 spindles concurrent with slow oscillations. Lower proportion of N2 bilateral spindles was associated with better composite memory performance in younger adults, whereas higher spindle power, regardless of cluster belonging, was associated with reduced memory benefit from sleep compared with wakefulness.

Conclusions: Our results indicate differing expression of spatiotemporal spindle clusters in older age, as well as intertwined dynamics between spindle propagation, slow oscillation concurrence, and frequency shifts in aging. In addition, spindle heterogeneity aligned with global sleep stage dynamics. These results emphasize the interconnectedness of spindle activity with overall sleep patterns, underscoring the importance of spatiotemporal context within and across sleep stages.

Integrated alongside home-based passive sleep monitoring, high-frequency assessment of patient reported outcomes (PROs) could enhance both research and clinical care surrounding obstructive sleep apnea (OSA). However, traditional approaches to capturing OSA-related PROs are poorly suited for this purpose. Hence, we investigated the feasibility of a smartphone-based check-in approach to monitor daily PROs (e.g. mental, emotional, and physical) over a 6-month period in people referred for suspected OSA. We quantified and assessed change in the proportion of participants (n = 68; 54% female) who, on average, achieved an "adequate" self-report rate of ≥4 self-reports per week (out of a possible seven). Generalized additive models (GAMs) were used to investigate if OSA severity (apnea-hypopnea index; AHI) was associated with the probability of adequate initial uptake within the first two weeks, sustained engagement over time, and the probability of a self-report on any given day. Self-reports were made on 52.1% of all possible days, equating to (M ± SD) 3.6 ± 3.0 per week. Within the first week, 63.2% of participants achieved "adequate" self-report compliance; during weeks 4 and 12, these rates were 70.6% and 54.4% , respectively. Greater baseline AHI was associated with slower time-dependent decline in the probability of adequate self-report compliance in an exposure-response manner. Within-subjects, daily self-reports were more probable following nights of elevated AHI (absolute and mean-referenced). All GAM smooth terms: p < .00001. Findings demonstrate the feasibility of bi-daily PRO assessment via app-based check-ins for approximately 1 month in the context of clinical OSA and suggest that greater disease burden enhances sustained engagement with this monitoring approach. This paper is part of the Consumer Sleep Technology Collection.

Musical chords represent the most basic musical elements, conveying emotional information. During wakefulness, different musical chord categories elicit distinct neuronal correlates and emotions, with major chords typically inducing more positive and minor chords negative ones. However, it remains unclear whether the brain continues to process musical chords differently when presented during sleep. To address this question, we conducted a proof-of-concept study and presented musical major, minor, and dissonant chords to 47 healthy participants during nocturnal non-rapid eye movement sleep. Prior to sleep, participants rated the chords in valence and arousal. Sleep was recorded using polysomnography. Our analysis of event-related responses during sleep revealed significant differences between the three musical chord categories. Major chords induced the strongest negative amplitude approximately 800 ms after chord onset, indicated as peak-to-peak (PTP) amplitude from the earlier positive peak. Minor chords showed intermediate PTP amplitudes, while dissonant chords elicited the lowest PTP amplitudes. In the time-frequency domain, these differences were also apparent, including differences in slow-wave, theta, alpha, and sleep spindle bands across chord categories. Notably, experience in playing a musical instrument induced stronger differentiation of musical harmony during sleep compared with participants who never played a musical instrument. In conclusion, our findings suggest that the different processing of single musical chords persists during sleep, influenced by harmonic features and musical expertise in the context of Western musical conventions. Future research should explore whether longer and more complex harmonic features (e.g. chord sequences or musical pieces) are differentially processed by the sleeping brain.

Study objectives: Sleep irregularity is associated with elevated blood pressure (BP). Whether sleep regularity decreases BP is not known. We hypothesized that an intervention involving 2 weeks of sleep regularization would decrease BP in people with hypertension.

Methods: Eleven people with hypertension (four males/seven females, age: mean 53 [range 45-62 years]), body mass index (32 ± 6 kg/m²), but no other chronic disease were studied. We measured ambulatory BP and assessed sleep using actigraphy over a free-living baseline week. For the next 2 weeks, participants were asked to go to bed at the same time every night before reassessing their ambulatory BP. The standard deviations of bedtimes and sleep onset were used to measure variability. The minimal detectable change (MDC) in BP was calculated from 48 h of ambulatory BP monitoring to analyze individual responses.

Results: Bedtime variability (32.4 ± SD 17 vs. 7 ± 10 min, p = .001) and sleep onset variability (30 ± 17 vs. 7 ± 8 min, p = .011) decreased following the intervention; no other sleep parameters changed. Bedtime regularization significantly reduced 24-h systolic BP (-4 ± 4 mmHg) and diastolic BP (-3 ± 3 mmHg), mainly due to reduced nighttime systolic BP (-5 ± 7 mmHg) and diastolic BP (-4 ± 5 mmHg), all p < .05. ≥50 per cent of participants decreased their BP by more than the MDC₉₅ for 24-h BP.

Conclusions: In this proof-of-concept study, 2 weeks of bedtime regularization decreased 24-h and nighttime BP in people with hypertension, suggesting that this may be a simple, yet low-risk, adjunctive strategy to control BP in many people with hypertension. This ought to be tested in a larger randomized controlled trial.

Insomnia is increasingly recognized as a public health concern; however, undergraduate university students remain relatively understudied. This study aimed to estimate the overall pooled prevalence of insomnia symptoms in this population to inform the need for targeted care. For this systematic review and meta-analysis, we searched five databases to identify papers published between January 1, 1993, and January 17, 2025, which investigated the prevalence or proportion of insomnia in undergraduate university students using validated measures. Studies with biased samples were excluded. Study quality was assessed using the Joanna Briggs Institute Critical Appraisal Tool. Data were synthesized using random-effects meta-analysis and meta-regression. Subgroup analyses were conducted based on continent, screening instrument, field of study, and sampling method. The review was registered on PROSPERO (CRD42025617914). The search yielded 2379 non-duplicate citations, of which 48 met the inclusion criteria, contributing 55 prevalence estimates based on data from 95 938 students. The pooled prevalence of insomnia in undergraduate university students was 46.9% (95% CI = 40.1% to 53.6%). Heterogeneity was high (I ² = 99.8%). Meta-regression indicated that rates varied by continent and screening instrument. Findings suggest that nearly half of undergraduate students experience insomnia symptoms, highlighting the need for university-level responses that combine universal sleep health promotion with targeted interventions. Further methodologically rigorous and culturally sensitive research is required to guide policy and practice.

Idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) is characterized by the loss of atonia during REM sleep, causing dream-enacting behavior. Although iRBD occurs without any clear signs of neurodegenerative disorders, most patients with iRBD eventually develop Parkinson's disease or dementia with Lewy bodies, typically accompanied by cognitive decline. Hence, identifying a biomarker that reflects a neurophysiological state of iRBD has therapeutic potential. Here, we show that spatially clustered alpha (8-12 Hz) oscillatory activities in the scalp can predict cognitive performance in patients with iRBD. A cohort of 62 Korean patients with iRBD underwent resting-state electroencephalography (rsEEG) recordings and participated in the Montreal Cognitive Assessment tests, a common measure for cognitive function. Spectral analysis of the rsEEG data revealed that overall power and transient bursting parameters of alpha activity negatively correlated with Montreal Cognitive Assessment test scores. These results accounted for potential confounding factors such as the spatial distribution of the electrodes, age, sex, emotional states, and medication use. This finding was specific to the alpha activity because theta (4-8 Hz) and beta (12-30 Hz) oscillatory activities were not correlated with the cognitive test scores. Thus, these results suggest that clustered resting-state alpha activity is associated with cognitive impairments in iRBD. Our findings emphasize the importance of rsEEG dynamics in cognitive assessment and highlight the potential utility of rsEEG as an early biomarker for cognitive decline in iRBD patients.

Sleep is a fundamental biological process associated with diverse physiological and psychological functions, yet systematic, population-level, objective descriptions of its variation across demographic and psychological factors are still emerging. Here, we characterize age- and sex-related differences in sleep and their associations with mood using week-long actigraphy data from UK Biobank participants aged 44-82. Robust age- and sex-related differences in sleep were identified (n = 38 546) and replicated (n = 38 547), reflecting reliable nonlinear interactions between age and sex. Younger women slept about 17 min more than their male counterparts, though this difference diminished with age, with both sexes reducing total sleep duration in later life. Middle-aged individuals exhibited shorter sleep durations during the week, with weekend sleep increasing by as much as 50 min. Participants in their seventh and eighth decades showed more consistent sleep patterns throughout the week. Sleep patterns also suggest maintenance of total sleep duration: individuals reporting waking too early maintain sleep duration by going to sleep earlier, while individuals reporting sleeping too much fall asleep later but also wake later, again maintaining sleep duration. Self-reported depression and anhedonia were associated with reduced total sleep duration across multiple age groups and both sexes. By systematically mapping actigraphy-derived sleep features across demographic strata and linking them to subjective reports of sleep and mood, this study provides an integrated framework that complements and extends prior findings, offering a valuable reference point for future investigations of sleep-mood associations in large cohorts.

Insomnia is prevalent in multiple sclerosis (MS) and may negatively affect quality of life and brain health. Cognitive behavioral therapy for insomnia (CBT-I) is recommended as the first-line treatment, but access is limited due to a shortage of trained therapists. Fully automated digital CBT-I (dCBT-I) has been developed to expand availability. Its effectiveness in MS, and whether improvements in insomnia severity lead to benefits in fatigue, mental health, and cognitive function, remains unknown. This randomized controlled trial will examine the effectiveness of dCBT-I compared with patient education about insomnia (PE) in people with MS. We plan to invite all individuals in the Norwegian MS registry (>90% of people diagnosed with MS in Norway) to the trial with the aim of including 550 participants. Participants will be randomly allocated 1:1 to dCBT-I or PE. Outcomes will be assessed at baseline, 9 weeks, 6 months, and 12 months, with additional health registry data collected 5 years after randomization. The between-group difference in self-reported insomnia severity at 9-weeks is the primary endpoint (intention to treat). Secondary outcomes include between-group differences in fatigue, mental health, cognitive function, sleep and daytime activity with actigraphy, medication use, pain, alcohol use, quality of life, social and work functioning, and resource utilization and whether changes in fatigue, mental health and cognitive function are mediated by changes in insomnia severity. The study protocol is approved by the Norwegian Ethics Committees for Clinical Trials on Medicinal Products and Medical Devices (Ref: 623308) and is preregistered at ClinicalTrials.gov (ref: NCT06113666). A Digital Therapeutic to Improve Insomnia in Multiple Sclerosis: A Randomized Controlled Trial. (NorseMS) Sponsor: St.Olavs Hospital, Postboks 3250 Torgården, 7006 Trondheim.