Sleep Medicine

BackgroundEmerging research indicates that light exposure may influence sleep quality. Identifying key light-exposure behaviours associated with poor sleep quality in athletes may allow practitioners to efficiently screen for sleep difficulties and prioritise athletes for further assessment. Translating these findings into a practical screening tool could enhance willingness of high-performance professionals to monitor sleep and light exposure in athletes. HypothesisKey predictor variables identified by feature reduction techniques will lead to higher predictive accuracy in determining which light behaviours are associated with poor sleep quality in athletes. Study DesignCross-sectional study. Level of EvidenceLevel 3. Methods121 athletes from varying competitive levels completed questionnaires, including the Light Exposure Behaviour Assessment (LEBA) and Pittsburgh Sleep Quality Index (PSQI). Poor sleep quality was defined using the PSQI cut-off >5. Least absolute shrinkage and selection operator (LASSO) regression identified light exposure variables from the LEBA questionnaire most strongly associated with good and poor sleep quality in athletes. Three models were compared: a full-variable model (23 items), a factor-specific model (Factor 3: screen/device use), and a feature-reduced model (LASSO-selected items). ResultsPhone use before bed, checking phone/watch during the night, were identified as variables of greatest association with poor sleep quality and used for reduced feature set modelling. On an independent test set, the feature-reduced model achieved area under the curve (AUC) 0.83, sensitivity 0.70, and specificity 0.92. ConclusionsOur findings report that phone-related behaviours before and in bed are associated with a higher likelihood of poor sleep quality. These behaviours, combined with the developed nomogram, provide a preliminary, low-burden screening tool to identify athletes who may be experiencing sleep difficulties. The high specificity indicates that athletes flagged by the tool are likely to have genuine poor sleep quality, warranting further assessment to identify underlying causes and appropriate interventions. Clinical RelevanceEducation and interventions focused on light exposure factors were identified as most influencing sleep quality in a multifaceted athletic population and could be prioritised to optimise sleep quality. The developed sleep quality nomogram may be useful as a decision-making tool to improve sleep monitoring practice among practitioners.

IntroductionObstructive sleep apnea (OSA) is characterized by recurrent upper airway obstruction during sleep, leading to intermittent hypoxia, sleep fragmentation, and autonomic dysregulation. These disturbances contribute to nocturnal blood pressure (BP) surges and increased cardiovascular risk. While sleep-stage-dependent BP modulation is well established, high-resolution data on sleep-stage- specific systolic BP variability (BPV) in OSA are limited. This study examined beat-to-beat systolic BPV during N2 and rapid eye movement (REM) sleep and its relationship with sleep fragmentation indices in patients with moderate-to-severe OSA. MethodsClinically suspected OSA patients aged 18-65 years underwent overnight level I video polysomnography. Patients with apnea-hypopnea index (AHI) <15 events/h, central sleep apnea >35%, beta-blocker use, or excessive artifacts were excluded. Continuous systolic BP was estimated using a validated pulse transit time (PTT) method calibrated against cuff BP. Artifact-free 20-minute continuous segments were extracted separately from N2 and REM sleep. Sleep fragmentation metrics included number and duration of respiratory events, arousals, and area under the curve of oxygen saturation (AUC SpO2). BPV indices included mean systolic BP, standard deviation (SD), and coefficient of variation (COV). ResultsSixteen patients contributed 16 N2 and 16 REM segments. N2 sleep showed a higher number of respiratory events (p = 0.005) and arousals (p = 0.01) than REM sleep, while event duration and AUC SpO2 were comparable. Mean systolic BP was 126 {+/-} 12.5 mmHg during N2 and 130 {+/-} 14.9 mmHg during REM, with REM significantly higher than N2 (mean difference -3.62 mmHg; p = 0.01). BP variability was highest during REM (SD 7.12 [4.91-9.25] mmHg; COV 5.95 [3.89-6.84%), intermediate during N2 (SD 5.25 [4.02-6.75] mmHg; COV 4.42 [3.17-4.83%), and lowest during wake (p < 0.001). In N2 sleep, arousal duration predicted mean systolic BP (R{superscript 2} = 0.48, p = 0.0025), while AUC SpO2 strongly predicted SD and COV (R{superscript 2} = 0.74-0.79, p < 0.0001). REM-stage correlations were weaker and not predictive. ConclusionSystolic BP variability in OSA is strongly sleep-stage dependent, with REM sleep exhibiting exaggerated BP instability despite fewer respiratory events. Stage specific mechanisms linking arousals and hypoxia to BP regulation may underlie cardiovascular vulnerability in OSA.

IntroductionThe circadian clock is an internal, [~]24-hour biological timer that synchronizes physiology with the day-night cycle. Social jetlag (SJL) describes the misalignment between this internal clock and social schedules, a condition affecting approximately 70% of the population and linked to a spectrum of metabolic, mental, and cognitive health issues. This study examined how the 2022 FIFA World Cup disrupted normal childrens sleep routines and other associated factors from parents prospect. MethodsAn online, cross-sectional survey was distributed to parents (N=848). The questionnaire collected sociodemographic data, childrens habitual sleep habits, and changes perceived during the 2022 FIFA World Cup. SJL was defined as a [&ge;]1-hour delay in bedtime on weekends versus weekdays. Multivariable logistic regression analyses identified factors associated with perceived sleep changes and SJL. ResultsOver half (53.4%) of the children exhibited pre-existing weekend SJL. Children aged 5-11 (OR=1.847, p<0.001), higher socioeconomic status (OR=1.383, p<0.001), international residency (OR=2.845, p<0.001) were significant predictors of baseline weekend SJL. During the tournament, 33% and 17.8% of parents reported their children had delayed sleep ([&ge;]1 hour) on weekdays and weekends due to match watching, respectively. Regression analysis revealed that these parental perceived FIFA impact on their children sleep was significantly associated with weekdays SJL OR= 1.958, p=0.001 and weekends OR= 1.784, p=0.009 during the FIFIA season. DiscussionOur findings indicate that major social events can exacerbate circadian misalignment and SJL, likely driven by social conformation. The high prevalence of baseline SL confirms it is a widespread pediatric health issue. The vulnerability of the 5-11 age group shows SJL is not exclusively an adolescent problem. ConclusionMajor sporting events significantly disrupt childrens sleep schedules, compounding the public health issue of chronic SJL. Proactive guidance for families is needed during such events. More importantly, these findings underscore the urgent need for structural changes to align social schedules with pediatric circadian biology.

This study compared the effects of a 25-min nap opportunity and a 10-min non-sleep deep rest (NSDR) condition on perceptual, cognitive, and physical performance in physically active young adults. Sixty participants (26 female, 34 male; 22 {+/-} 4 years) were randomly assigned to one of three groups (nap, NSDR, control; n = 20 each). All groups completed identical assessments immediately, 20 min, and 40 min post-intervention. Mixed-effects models, adjusted for sex, prior-night sleep, and weekly physical activity, revealed a significant Group x Time interaction for sleepiness, fatigue, readiness to perform, and handgrip strength (p < 0.05). At 40 min post-intervention, the nap group reported lower fatigue than control and higher readiness to perform than both control and NSDR (p < 0.05). No significant effects were observed for the NSDR condition on perceptual, cognitive, or physical outcomes (p > 0.05). These findings indicate that a short nap can enhance perceived readiness and reduce fatigue after a brief latency period, whereas NSDR did not elicit significant effects under the present conditions.

IntroductionUnilateral hypoglossal nerve stimulation (HGNS) is an approved surgical therapy for obstructive sleep apnea (OSA), but its efficacy is limited by obesity and unfavorable (laterally directed) pharyngeal collapse patterns. This study tested whether the effect of body mass index (BMI) on HGNS efficacy differs by pharyngeal collapse pattern, specifically comparing laterally directed and anteroposterior (AP) collapse. MethodsWe pooled data from two independent HGNS cohorts (n=760) to evaluate the interaction between BMI and pharyngeal collapse pattern on HGNS efficacy. Collapse sites were identified via drug-induced sleep endoscopy (DISE) and grouped as laterally directed or AP directed. Multivariable mixed model regression evaluated the association between HGNS efficacy, largely based on optimal setting AHI during titration polysomnogram (primary: percent reduction in apnea-hypopnea index [AHI]; secondary: success defined as [&ge;]50% AHI reduction to <15 events/h) and the interaction between collapse pattern and BMI, adjusting for baseline AHI, partial collapse, surgical center, type of follow-up sleep study, and prior or concomitant pharyngeal surgery. ResultsGreater BMI was associated with a larger reduction in HGNS efficacy in those with lateral collapse (-19.7% [95% CI: -33.2, -6.2] per 5 kg/m{superscript 2}) than in those with AP collapse (-3.8% [-8.0, 0.36]; p-interaction=0.027). In lateral collapse, greater BMI reduced the odds of treatment success (odds ratio [95% CI]: 4.4 [1.4, 14.3] per 5 kg/m{superscript 2}), with no significant effect in AP collapse (1.1 [0.75, 1.5]; p-interaction=0.023). ConclusionThe impact of BMI on HGNS efficacy varies by collapse pattern. Tailoring BMI criteria to collapse pattern may improve HGNS candidate selection.

Background: Nursing interns are at high risk of psychological distress due to academic and clinical stressors. While poor sleep quality is linked to anxiety and depression, the buffering role of social support remains underexplored in this population. Aims: To explore the role of social support in regulating the relationship between sleep and mental health among nursing interns. Methods: A total of 396 nursing interns completed self-administered questionnaires including the Pittsburgh Sleep Quality Index (PSQI), Social Support Rate Scale (SSRS), Generalized Anxiety Disorder-7 (GAD-7), and Patient Health Questionnaire-9 (PHQ-9). Hierarchical regression and simple slope analyses were used to test moderation effects. Results: Poor sleep quality was significantly associated with higher anxiety ({beta}=0.449, P<0.001) and depression ({beta}=0.535, P<0.001). Social support significantly moderated these relationships. Under low social support, the effects of sleep quality on anxiety ({beta} = 0.602) and depression ({beta} = 0.779) were stronger than under high support (anxiety: {beta} = 0.396; depression: {beta} = 0.515). Conclusions: Social support buffers the adverse psychological effects of poor sleep among nursing interns. Interventions should integrate sleep hygiene education with strategies to enhance social support.

IntroductionSleep is a vital physiological process essential for memory consolidation, cognitive performance, and the regulation of cardiovascular functions. Students in health sciences programs constitute a population particularly susceptible to sleep disturbances due to heavy academic workloads, irregular schedules, and psychosocial stressors. ObjectiveTo investigate the relationship between sleep patterns, academic performance, and cardiovascular risk factors among health sciences students. MethodsA cross-sectional study was conducted involving 349 students enrolled in Medicine, Psychology, and Nursing programs. Participants completed a sociodemographic questionnaire, the Pittsburgh Sleep Quality Index (PSQI), and the Epworth Sleepiness Scale (ESS). Anthropometric data, including weight, height, waist circumference, and blood pressure were measured. Statistical analyses comprised descriptive and inferential methods. ResultsA high prevalence of poor sleep quality and excessive daytime sleepiness was identified. Sleep quality was significantly associated with academic performance (p = 0.003). Male sex, smoking, and higher body mass index (BMI) were also correlated with poorer sleep patterns. ConclusionPoor sleep quality adversely affects academic performance and is associated with cardiovascular risk factors. The implementation of institutional strategies aimed at promoting sleep hygiene and providing psychosocial support is recommended to mitigate these impacts.

BackgroundDespite cardiovascular disease being a leading cause of death globally, secondary prevention strategies following myocardial infarction are under-researched compared to primary prevention. ObjectivesTo explore relationships between indicators of sleep quality, inflammation, and myocardial infarction recurrence and the conditional role of psychological stress in these pathways to assess evidence for reducing MI recurrence by improving sleep quality and implementing stress management techniques. MethodsA secondary analysis (N = 156) of cross-sectional study data was conducted. Participants mean age was 65 years and all had experienced one or more myocardial infarctions within the previous 3-7 years. Sleep quality was measured using the Pittsburgh Sleep Quality Index. Inflammatory markers were collected via blood assay and included C-reactive protein, interleukin-6, and tumor necrosis factor-alpha. Psychological stress was evaluated using a self-reported Likert-scale question. Correlational analysis and conditional path analyses examined relationships between variables of interest. ResultsSignificant associations between sleep quality, inflammation, psychological stress, and MI recurrence were observed. Sleep quality predicted elevated inflammation markers. Psychological stress moderated the relationship between sleep quality and MI recurrence, with higher stress amplifying the risk. Sleep quality did not directly predict MI recurrence. ConclusionFindings suggest that improving sleep quality may be an effective secondary prevention strategy for reducing MI recurrence. The effect may be increased when combined with targeted stress management interventions. Further research is warranted to explore biobehavioral mechanisms underlying these associations to develop targeted interventions for aging individuals at risk.

BackgroundThe maintenance of wakefulness test (MWT) measures the ability of an individual to maintain wakefulness in soporific conditions and despite limitations remains the mainstay of vigilance testing. Wake and sleep states are traditionally characterised by oscillatory activity on electroencephalogram (EEG) but there is a less utilised non-oscillatory component of background neural aperiodic activity which can be derived from EEG raw data and represented as an exponent or a gradient (1/f slope). There is emerging evidence that aperiodic activity can be used to predict cortical activity. The aim of this study is to assess the use of aperiodic activity as a novel neurobiological marker of vigilance. MethodsEEGs (4 x 50) from 50 patients who underwent the MWT between 2009 and 2023 at a single centre were analysed to determine their aperiodic activity. Statistical analyses utilising linear mixed models and linear regression were performed to assess the relationship between aperiodic exponent, aperiodic intercept and mean sleep latency. ResultsLinear mixed-effects modelling revealed that more negative aperiodic exponents represented by steeper 1/f slopes were associated with longer sleep onset latencies ({beta}=-8.08, p=0.002). Similarly, higher aperiodic intercept scores were associated with longer sleep onset latencies ({beta}=2.36, p=0.01). ConclusionThis study provides proof-of-concept that aperiodic activity may be predictive of vigilance. Given its practicality, cost-effectiveness and lower demand on health staff and patient time, it is suggested that aperiodic activity as a test of vigilance testing offers not only greater diagnostic objectivity but benefits to already resource-limited healthcare systems. Brief SummaryThe current gold standard for vigilance testing is the maintenance of wakefulness test (MWT) which measures the ability of an individual to maintain wakefulness in soporific conditions. Despite its advantages, the MWT is resource intensive and time consuming which has led to the exploration of alternative markers of wakefulness. Our study provides proof of concept that neural aperiodic activity may be a viable alternative or adjunct to current vigilance tests. Further, we describe the ease at which analysis of the aperiodic activity is performed and the potential advantages of its utility in clinical practice.

Structured AbstractO_ST_ABSBackgroundC_ST_ABSHair cortisol analysis allows assessment of long-term cortisol exposure and may provide insight into chronic hypothalamic-pituitary-adrenal activation in medical residents and residency on-call responsibilities. ObjectiveTo determine the hair cortisol concentration(HCC) representing 3 months of medical residency and secondarily, its association with various on-call models (in-hospital, night float, home call and no call). DesignCross-sectional study of 66 medical residents who were recruited to provide hair samples collected after a three-month block in medical residency. SettingAcademic, tertiary health care system. ParticipantsVolunteer sample of first through third year medical and primary care residents. Exposure3 cm of hair was divided into 3 segments of 1 cm each; each segment represented 1 month of cumulative cortisol production. Main Outcome MeasureHCC results were compared to a published, cortisol assay-specific normative population reference interval. HCC results were interpreted according to a priori categorizations of moderate (+1.5SD), considerable (+2SD) or extreme (> +3SD) HCC elevations. Associations with various on-call models were an exploratory secondary outcome. ResultsThe median age was 28 (26-30) years with median sleep duration of 2 hours on in-hospital call. 40% of trainees had at least one HCC segment above the threshold deemed marked elevation. Median HCC was significantly higher for in-hospital and night float vs. no call (285 ng/g and 335 ng/g vs 78 ng/g p<0.05) and approached significance compared to home call (190 ng/g, p= 0.06). Conclusions and RelevanceWe have described chronic exposure to endogenous cortisol in medical residency. Nearly half of trainees experienced at least one month of severe hypothalamic-pituitary-adrenal axis activation in a 3-month timeframe; many had marked chronic cortisol elevations across the entire 3 month observation frame. HCC was higher in months where in-hospital on-call was required. This may have implications for long-term health of trainees and raises questions about the structure of duty hours and sequence of care acuity blocks within residency training programs.

Sleep architecture is essential for metabolic and cardiovascular health, yet the impact of day-to-day dietary variation on objective sleep physiology remains unclear. Using 4.8 thousand person-nights with real-time dietary logs and multi-stage wearable sleep recordings, we examined how prior-day nutrition relates to next-night sleep under free-living conditions. Higher fiber density was associated with increased restorative sleep, including +0.59 pp deep sleep, +0.76 pp REM sleep, -1.35 pp light sleep, and -1.14 bpm lower mean nocturnal heart rate. Greater plant diversity and higher whole-plant food intake were similarly associated with lower nocturnal heart rate (-0.72 to -0.94 bpm). Meal-timing behaviors primarily influenced sleep duration, sleep-onset latency, and autonomic tone: heavier evening meals were associated with +7.7 min longer total sleep time and +0.73 bpm higher nocturnal heart rate. In contrast, short-term variation in macronutrient energy distribution and micronutrient consumption showed no robust associations with sleep outcomes. When analyses were restricted to more extreme dietary contrasts, effect magnitudes increased while remaining directionally consistent. These findings indicate that routine daily dietary choices, particularly plant-forward composition and meal timing, have immediate and measurable effects on objective sleep architecture.

BackgroundWhile accurate sleep measurement is vital for older adults, the validity of actigraphy (AG) in free-living environments remains controversial, particularly given the flexible sleep-wake schedules common in this demographic. To address this uncertainty, we assessed the accuracy of wrist AG against in-home portable electroencephalography (EEG) among community-dwelling older adults. MethodsCommunity-dwelling older adults underwent concurrent sleep monitoring using a portable EEG device and a wrist-worn AG for five consecutive nights whenever possible, with monitoring extended to up to seven nights when feasible. Key sleep parameters, including total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency, were derived from both devices. Measurement agreement was assessed using Bland-Altman plots and multilevel modeling, while reliability and accuracy were quantified via intraclass correlation coefficients (ICCs) and mean absolute percentage error (MAPE). ResultsForty-nine adults contributed 217 nights of recordings. On average, AG slightly overestimated TST and sleep efficiency and underestimated SOL and WASO compared with EEG. Single-measure ICCs were 0.73 for TST and 0.38 for WASO (0.84 and 0.55 for averages across nights), and the MAPE was 11% for TST but exceeded 50% for SOL and WASO, indicating poor accuracy for these indices. ConclusionIn community-dwelling older adults, wrist AG yielded acceptably accurate estimates of average TST, supporting its use in epidemiological monitoring of sleep duration. However, large errors for SOL and WASO indicate that portable EEG- or polysomnography-based assessment remains indispensable when precise evaluation of sleep initiation and nocturnal wakefulness is required.

Background/ObjectiveBarriers in access to care have prompted development of innovative care delivery models for patients with obstructive sleep apnea (OSA). One such innovation is management of uncomplicated OSA by primary care providers (PCPs), which reserves specialist capacity for more complex patients. We developed a clinical guideline and subsequently, an online clinical pathway to support PCPs in OSA management. We aimed to evaluate the impact of these initiatives on PCP behaviour by assessing changes in the complexity of newly referred patients. MethodsWe compared data for new OSA referrals to the Foothills Medical Centre Sleep Centre in Calgary, Canada, received during three distinct referral periods: prior to the clinical guideline (November 2016 - March 2017; Period 1), after implementation of the clinical guideline (April 2017 - November 2018; Period 2), and after publication of the online primary care pathway (December 2018 - November 2019; Period 3). The primary outcome was OSA severity as defined by the oxygen desaturation index (ODI) on home sleep apnea testing performed at the time of referral. Secondary outcomes included severity of daytime sleepiness and proportion of patients with severe OSA or severe daytime sleepiness at the time of referral. Multivariable linear and logistic regression models were constructed to quantify the associations between study outcomes and Period after adjustment for baseline covariates. ResultsAmong the 2489 patients with sleep study data available, patients referred in Period 3 had more severe OSA (ODI, mean nocturnal oxygen saturation, proportion with severe OSA) compared to patients referred in earlier Periods. Severity of sleepiness did not increase across Periods. In multivariable analysis adjusting for demographics and comorbidities, ODI was significantly associated with Period (regression coefficient 1.70 (0.39, 3), p = 0.011) but severe OSA was not (odds ratio 1.17 (0.99, 1.39), p = 0.069). ConclusionsOSA severity increased following implementation of educational resources to support primary care OSA management. These findings suggest that with appropriate supports, PCPs may be more comfortable managing less severe OSA patients independently and only refer more severe cases for specialist consultation.

ObjectiveDigital cognitive behavioral therapy for insomnia (CBT-I) is an effective and scalable treatment for chronic insomnia. However, treatment outcomes are typically evaluated using aggregated symptom scores, which obscure differential effects on individual symptoms and limit insights into underlying mechanisms. This study applied network intervention analysis (NIA) to investigate how somnovia, a self-guided digital CBT-I intervention, is associated with changes in individual symptoms of insomnia, depression, and anxiety over time. MethodThis secondary analysis used data from a randomized controlled trial including 290 adults with chronic insomnia who were randomized to somnovia plus treatment as usual or treatment as usual alone. Using item-level data from the Insomnia Severity Index (ISI), Patient Health Questionnaire-9 (PHQ-9), and Generalized Anxiety Disorder-7 (GAD-7) collected at baseline, 3 months, and 6 months, NIA was conducted to identify direct and indirect associations between treatment assignment and individual symptoms. ResultsAt 3 months, somnovia was primarily associated with reductions in sleep-related worry, dissatisfaction with sleep quality, and difficulties relaxing, indicating early effects on cognitive and physiological arousal processes. Improvements in other symptoms appeared to occur indirectly through these core arousal-related processes. By 6 months, treatment-related associations were more broadly distributed across the symptom network, consistent with generalized improvements extending beyond sleep-specific complaints. ConclusionTogether, these findings suggest that somnovia exerts its clinical effects by reducing hyperarousal as a central transdiagnostic process, through which improvements in insomnia may contribute to sustained benefits in broader mental health outcomes, including symptoms of depression and anxiety. Trial RegistrationClinicalTrials.gov (NCT05558865).

BackgroundExcessive daytime sleepiness (EDS) is a major yet under-recognized contributor to road traffic accidents. Traditional diagnostic tools, such as the Maintenance of Wakefulness Test (MWT), assess wakefulness under passive conditions but may not accurately reflect real-world driving risks. To address this gap, we have piloted a Driving Simulation-based MWT (DS-MWT), designed to evaluate sleepiness in an ecologically valid driving scenario. The present study aims to validate the novel DS-MWT against the classical MWT in a functionally relevant cohort of patients with obstructive sleep apnoea (OSA). MethodsThe present monocentric, randomized, controlled, within-subject crossover trial will include 54 participants: 36 patients with OSA undergoing[&ge;] 7-day CPAP withdrawal (W) or continuation (C), and 18 healthy controls. The study employs a well-established CPAP-withdrawal model in patients with prior optimal treatment adherence to transiently induce EDS under controlled conditions. A healthy control group is included to enable between-group comparisons. The primary expected outcome is the difference in mean latencies between MWT and DS-MWT, determined during four standardized test sessions per condition. Secondary exploratory outcomes are defined as the presence, direction, and magnitude of differences or correlations between treatment status (CPAP withdrawal vs. continuation) and driving performance metrics (e.g., lateral position, speed, lane departures, etc.), EEG and eye-tracking features, subjective sleepiness scores, at-home polysomnography (PSG) parameters, and metabolomic biomarkers (saliva, exhaled breath and dried blood spots). Data will be analyzed using linear mixed models, repeated-measures ANOVA, and predictive modeling with cross-validation. DiscussionThis trial addresses a critical limitation in sleep and traffic medicine by introducing a realistic, supposedly more ecologically valid alternative to standard sleepiness assessment tools. The DS-MWT may enhance clinical decision-making regarding fitness to drive (FTD) and provide a framework for identifying physiological and behavioral markers of sleepiness in realistic conditions. Trial registrationClinicalTrials.gov Identifier: NCT06872593, released on 12.03.2025, https://clinicaltrials.gov/study/NCT06872593 Swiss National Clinical Trial Portal SNCTP000006301, released on 19.03.2025, https://www.humanforschung-schweiz.ch/en/trial-search/study-detail/66469

To characterize sleeping posture, behaviour, and environment in healthy pregnant participants and their bed partners across multiple nights in the home setting during late pregnancy, we completed a manual review of overnight video recordings from a four-night, in-home, level 3 sleep apnea study. Sleeping postures were scored according to a thirteen-posture classification system to determine the cumulative time per night spent in each sleeping posture. Additional aspects of sleeping posture, behaviour, and environment were also assessed. Forty-one pregnant participants and 36 bed partners completed the study, contributing 168 nights of video. Significant differences were found between the pregnant participants and bed partners in cumulative time spent in each posture as well as frequency and duration of episodes spent in each posture. Pregnancy status, side of the bed, and presence of a pregnancy pillow, bed partner, shared bed sheets, and pets in the sleeping space had various effects on the time spent in each posture. Pregnant participants spent more time in transition postures (going-to-sleep, waking-to-void, returning-to-bed, and waking-in-the-morning) than bed partners. There was a moderately positive correlation in posture changes between pregnant participants and their bed partners. Pets significantly increased the number of posture changes per night for both groups. Pregnant participants had more absences and time absent from bed. Sleep in late pregnancy is characterized by an increased frequency and duration of episodes spent in a restricted number of sleeping postures and is impacted by the sleep environment. Modifying the sleeping environment may improve comfort, minimize disturbances, and benefit sleep. Statement of SignificanceSubjectively-recalled supine going-to-sleep posture in late pregnancy is associated with stillbirth and fetal growth restriction. Sleeping posture, however, is dynamic, and few studies provide comprehensive analyses of sleeping posture in pregnancy using objective measurements. This novel study used a gold-standard objective measure of sleeping posture, was conducted across multiple nights in the participants own homes, and accounts for usual sleeping behaviours and environment by including the participants bed partner. A critical remaining knowledge gap is whether an individuals nightly sleeping posture varies significantly across the third trimester. Future work should use nightly, continuous, and objective methods to measure sleeping posture across the entire third trimester to bridge this gap and investigate the relationship between sleeping posture and pregnancy outcomes.

BackgroundThe cognitive demands of medical education require optimal learning environments. While the influence of background music on cognition has been widely studied, existing research exhibits a significant Eurocentric bias, predominantly focusing on Western classical music like the "Mozart Effect." This leaves a critical gap in understanding the impact of culturally salient, non-Western musical traditions on learning within their native contexts. MethodsA single-blind, randomized controlled trial was conducted with 147 clinical (4th, 5th and 6th) year medical students stratified by ethnicity at the Faculty of Medicine, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria between March and September 2025. Participants were randomly assigned to one of three background music conditions: Igbo Highlife (instrumental), Western classical (Mozarts Sonata K.448), or silence (control with pink noise masking). Cognitive performance was assessed through a short-term memory recall test of 20 medical terms and a timed clinical problem-solving task comprising 20 multiple-choice questions. Baseline mood was controlled for using the Positive and Negative Affect Schedule (PANAS). Data were analyzed using ANOVA and post-hoc Tukey HSD tests. ResultsMusic condition had a highly significant effect on student performance (p < 0.001). The Igbo Highlife group demonstrated superior outcomes, achieving the highest scores in memory recall (mean = 16.7) and problem-solving accuracy (mean = 15.7), alongside the fastest completion time (23.4 seconds/question), significantly outperforming both the classical and silence groups. A significant correlation was found between cultural familiarity with Highlife and enhanced cognitive performance (accuracy: {rho} = 0.268, p = 0.001). ConclusionsIncorporating music that holds cultural significance and familiarity to learners, specifically Igbo Highlife, is a highly effective auditory stimulus for enhancing learning efficiency in medical education. Students and educational institutions should consider integrating culturally familiar instrumental music into study environments to optimize cognitive performance and learning outcomes. Competing Interest StatementThe authors have declared no competing interest.

Sleep arousals trigger rapid autonomic shifts, yet their specific sympathetic signatures remain poorly characterized due to the mixed sympathetic-parasympathetic nature of traditional cardiovascular markers. Electrodermal activity (EDA), driven exclusively by sympathetic sudomotor pathways, offers a more direct opportunity to characterize arousal-related autonomic responses during sleep. This study quantifies the evolution of EDA-based features associated with arousal events in 100 adults using polysomnography and high-resolution EDA recordings. We implemented a time-varying frequency decomposition framework to isolate sleep-specific sympathetic components, extracting statistical and peak-based features from arousal segments and matched stable-sleep controls. Compared to controls, arousal segments exhibited robust sympathetic modulation in EDA persisting 40 seconds post-arousal. While long arousals produced robust responses, short arousals showed negligible sudomotor responses. REM and NREM sleep showed consistent feature trajectories, with greater variability during REM. The observed activation is primarily driven by clustered sympathetic bursts and amplitude enhancement rather than shifts in peak frequency. These findings establish EDA as a highly sensitive marker of sleep-related autonomic activation and provide a quantitative baseline for characterizing sympathetic responses to sleep arousals.

Background/ObjectivesElectromyography (EMG), video-polysomnography (vPSG), and wrist actigraphy are each used to develop diagnostic algorithms for Rapid eye movement sleep behavior disorder (RBD). However, the extent to which they capture overlapping versus distinct motor phenomena remains unknown. We evaluated the respective contributions of actigraphy, EMG and vPSG to the measurement of REM-sleep motor activity. MethodsSeventeen adults with RBD (Mount Sinai n = 9; Stanford n = 8) and eight control participants from an open Newcastle dataset underwent vPSG and concomitant wrist actigraphy. Flexor digitorum superficialis EMG activity and video-detected movements were manually scored in 3-second mini epochs. Actigraphy was quantified using an acceleration-magnitude-based activity count model. Statistical and agreement analyses were performed to assess the motor events captured by all three, any two, or by each modality independently during REM sleep. ResultsIn participants with RBD, actigraphy-derived movement load was significantly higher during REM sleep than during non-REM stages, a pattern not observed in control participants. Across 12,941 3-second mini epochs, EMG, actigraphy, and video detected 1,703, 1,613, and 811 motor events, of which 413 were detected concurrently by all three modalities. Pairwise agreement was moderate and increased from EMG-actigraphy ({kappa} = 0.27 {+/-} 0.10) to actigraphy-video ({kappa} = 0.41 {+/-} 0.12) and EMG-video ({kappa} = 0.45 {+/-} 0.15). Of EMG-detected events, 49.0% were also detected by actigraphy; of actigraphy-detected events, 37.2% were detected by EMG and 34.9% by video. Actigraphy activity counts were highest for events detected by all three modalities and lowest for actigraphy-only events. ConclusionActigraphy-measured REM-related motor activity was elevated in RBD but not in controls. EMG, actigraphy, and video captured partially overlapping motor events in RBD patient, with actigraphy showing the highest sensitivity and manually scored video the lowest.

BackgroundAuditory steady-state responses (ASSRs) provide an objective method for estimating hearing thresholds in individuals unable to provide behavioural responses. Bone conduction (BC) testing is required to differentiate conductive from sensorineural hearing loss. Accurate BC ASSR threshold estimation relies on "correction" factors, which are not yet well established. This meta-analysis evaluated the reliability of BC ASSR thresholds to estimate hearing thresholds at 500, 1000, 2000 and 4000 Hz. MethodsA systematic search of PubMed, the Cochrane Library, and Embase was conducted to identify studies involving normal-hearing (NH) and hearing-impaired (HI) participants of all ages. Outcomes were (1) the difference between ASSR behavioural and ASSR thresholds, and (2) ASSR thresholds. The risk of bias was evaluated using the Newcastle-Ottawa Scale. The mean and 95% confidence intervals (CI) were calculated for the thresholds at the four frequencies. The certainty of the evidence was assessed using GRADE approach. ResultsOf records identified, 11 records met the inclusion criteria, yielding a total of 27 studies. Sample sizes ranged from 60 to 249 participants across frequencies and age groups. The quality of records ranged from low to high. Data were synthesised using random-effects models due to heterogeneity. In NH adults, the mean differences ({+/-}95% CI) between BC ASSR thresholds and behavioural thresholds were 17.0 ({+/-}4.8), 15.5 ({+/-}6.0), 13.4 ({+/-}3.3), and 12.1 ({+/-}4.1) dB at 500, 1000, 2000, and 4000 Hz, respectively. In NH infants, mean ({+/-}95% CI) BC ASSR thresholds were 17.2 ({+/-}2.2), 10.5 ({+/-}3.6), 26.4 ({+/-}2.7), and 19.9 ({+/-}4.0) dB HL at the same frequencies. The certainty of the evidence was very low. ConclusionsBC ASSR can be a reliable method for estimating BC thresholds. However, age and frequency significantly impact BC ASSR thresholds, highlighting the need to develop of "correction" factors to accurately predict BC behavioural thresholds. RegistrationPROSPERO CRD42023422150.