Sleep deprivation, vigilant attention, and brain function: a review

Temporal bisection task as a predictor of cognitive deficits

Evidence suggests that neuropsychiatric symptoms and deficits in attentional control and executive function can impair time discrimination, demonstrating the intricate link between cognitive processes, subjective well-being, and perception of time. However, the relationship between sleep quality and time discrimination remains elusive. This study aimed to understand differences in the temporal bisection task (TBT) performance. We expected that individuals with impaired cognition, executive function, quality of life, or sleep quality would have reduced time sensitivity. At the same time, those with stress, anxiety, or depression would show a shift in the point of subjective equality. Data were collected from 97 female participants (ranging from 20 to 72 years of age) in more than one moment, resulting in 163 measurements used for the analysis. Participants' neuropsychiatric status was assessed using a battery of tests and scales, including the Mini-Mental State Examination (MMSE), the Frontal Assessment Battery (FAB), the World Health Organization Quality of Life Questionnaire (WHOQOL), the Pittsburgh Sleep Quality Index (PSQI), and the Depression, Anxiety, and Stress Scale-21 items (DASS-21). The results showed that attention and executive control significantly affect time discrimination. In addition, the research indicated that better sleep quality is associated with improved time discrimination sensitivity.

Enhanced diversity on connector hubs following sleep deprivation: Evidence from diffusion and functional magnetic resonance imaging

Sleep deprivation has been demonstrated to exert widespread and intricate impacts on the brain network. The human brain network is a modular network composed of interconnected nodes. This network consists of provincial hubs and connector hubs, with provincial hubs having diverse connectivities within their own modules, while connector hubs distribute their connectivities across different modules. The latter is crucial for integrating information from various modules and ensuring the normal functioning of the modular brain. However, there has been a lack of systematic investigation into the impact of sleep deprivation on brain connector hubs. In this study, we utilized functional connectivity from resting-state functional magnetic resonance imaging, as well as structural connectivity from diffusion-weighted imaging, to systematically explore the variation of connector hub properties in the cerebral cortex after one night of sleep deprivation. The normalized participation coefficients (PCnorm) were utilized to identify connector hubs. In both the functional and structural networks, connector hubs exhibited a significant increase in average PCnorm, indicating the diversity enhancement of the connector hub following sleep deprivation. This enhancement is associated with increased network cost, reduced modularity, and decreased small-worldness, but enhanced global efficiency. This may potentially signify a compensatory mechanism within the brain following sleep deprivation. The significantly affected connector hubs were primarily observed in both the Control Network and Salience Network. We believe that the observed results reflect the increasing demand on the brain to invest more effort at preventing performance deterioration after sleep loss, in exchange for increased communication efficiency, especially involving systems responsible for neural resource allocation and cognitive control. These results have been replicated in an independent dataset. In conclusion, this study has enhanced our understanding of the compensatory mechanism in the brain response to sleep deprivation. This compensation is characterized by an enhancement in the connector hubs responsible for inter-modular communication, especially those related to neural resource and cognitive control. As a result, this compensation comes with a higher network cost but leads to an improvement in global communication efficiency, akin to a more random-like network manner.

Sleep apnea evokes right hemisphere dominance and psychological disorders: An exploratory study

BACKGROUND

Obstructive sleep apnea (OSA) is considered one of the major causes of sleep disorders and psychological disorders in individuals. Brain asymmetry (BA) demonstrates individual hemispheric activity and psychological disorders. This study aimed to explore the characteristics of BA and psychology in OSA.

METHODS

Enrolment of patients for sleep assessment at the Sleep Medicine Center. Clinical characteristics, handedness, and psychological scales were prospectively collected from subjects. Subsequently, EEG power in alpha, beta, and theta bilaterally was calculated for the rest and sleep phases.

RESULTS

A total of 152 OSA and 21 non-OSA subjects were included in the study. In the frontal, central and occipital regions, OSA exhibited increased interhemispheric asymmetry with increasing apnea-hypopnea index (AHI) during rest and sleep. Simultaneously, the results showed that greater activity in the right hemisphere was positively associated with anxiety and extraversion, while inversely with positive and lie scale. In addition, the results show that OSA contributes to abnormal BA fluctuations during sleep.

CONCLUSIONS

Our results suggest that sleep disorders associated with apnea-hypopnea and arousal may contribute to increased BA during sleep. Such changes may persist into wakefulness with psychological traits.

Caffeine and modafinil modulate the effects of sleep deprivation on thalamic resting-state functional connectivity: A double-blind pilot study

BACKGROUND

Studies have found that the use of clinically approved caffeine and modafinil can alleviate cognitive impairment due to sleep deprivation (SD) to some extent. However, the neural mechanisms by which these two cognitive enhancers work to counteract the effects of SD on cognitive impairment remain unclear.

METHODS

A double-blind within-subjects experiment using resting-state functional magnetic resonance imaging (rs-fMRI) was designed. Participants underwent three 36-h SD trials, each of which involved taking 200 mg of caffeine, modafinil, or placebo at the 28th and 32 nd h of SD. Sixteen subregions of the thalamus were selected as the regions of interest and changes in functional connectivity (FC) between the thalamus and the other brain regions were explored after the participants took caffeine or modafinil.

RESULTS

The subjective sleepiness of the participants increased with the duration of SD. compared with placebo, modafinil and caffeine had insignificant effects on wakefulness or sleepiness. However, in terms of neural FC, we found varying degrees of attenuation or enhancement of the FC between the thalamus and other regions. Taking caffeine during SD weakened the FC between the right rostral temporal thalamus (rTtha) subregion and the left lingual gyrus compared with placebo. Caffeine enhanced the FC between three subregions of the thalamus, namely the left sensory thalamus, the left rTtha, and the right lateral pre-frontal thalamus, and the right inferior temporal, left orbitofrontal, and right superior occipital gyris. Modafinil weakened the FC between the right posterior parietal thalamus and left middle temporal gyrus, and enhanced the FC between the left medial pre-frontal thalamus, left rTtha, and right occipital thalamus and left middle frontal gyrus.

CONCLUSIONS

After 36 h of total SD, modafinil and caffeine administration enhanced or attenuated the time-domain correlations between various subregions of the thalamus and brain regions of the frontal and temporal lobes in healthy adults, compared with placebo. These results provide valuable evidence for further unraveling the neuropharmacological mechanisms of caffeine and modafinil, as well as important insights for exploring effective pharmacological intervention strategies against SD.

Electroacupuncture inhibits hippocampal oxidative stress and autophagy in sleep-deprived rats through the protein kinase B and mechanistic target of rapamycin signaling pathway

OBJECTIVE

To investigate the effects of acupuncture on learning and memory impairment, oxidative stress and autophagy induced by sleep depriv ation in rats, and to analyze the related mechanism.

METHODS

Thirty Wistar rats were randomly divided into a normal group, sleep deprivation group and acupuncture group. The rat model of sleep deprivation was established by a modified multiplatform sleep deprivation method. The Baihui (GV20), Shenmen (HT7) and Sanyinjiao (SP6) acupoints of rats were located to give electroacupuncture (density wave, frequency 20 Hz, intensity 1 mA) to maintain the needle feeling, and to keep the needle for 15 min and continuous acupuncture for 7 d. The spatial learning and memory abilities of the rats were detected by the water maze test. The content of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) in the brain were detected by an assay kit, and the autophagy related proteins light chain 3 alpha (LC3A), light chain 3 beta (LC3B) and Beclin 1 and the activation of the protein kinase B (PKB/AKT) and mechanistic target of rapamycin (mTOR) signaling pathway in the rat's brain were detected by Western blotting.

RESULTS

Compared with the normal group, the time spent in the target quadrant (P < 0.05) and the number of times entering the target quadrant (P < 0.05) in the rats of sleep deprivation group were significantly reduced, and the content of MDA was significantly increased (P < 0.01), while the activities of SOD and GPX (P < 0.01) in the brain were significantly decreased, and LC3A Ⅱ/Ⅰ, LC3B Ⅱ/Ⅰ and Beclin 1 increased significantly (P < 0.01), while p-AKT (ser473)/AKT, p-mTOR (ser2448)/mTOR and p-p70s6K (thr389)/p70S6 decreased significantly (P < 0.01). Compared with the sleep deprivation group, the time spent in the target quadrant and the times of entering the target quadrant (P < 0.05) in the rats of acupuncture group after 7 d of treatment were significantly increased, Additionally, the content of MDA was significantly decreased (P < 0.05), while the activities of SOD and GPX (P < 0.05) in the brain were significantly increased. Moreover, the levels of LC3A Ⅱ/Ⅰ, LC3BⅡ/Ⅰ and Beclin 1 decreased significantly (P < 0.05), and that of p-AKT (ser473)/AKT, p-mTOR (ser2448)/mTOR and p-p70s6K (thr389)/p70s6k increased significantly (P < 0.05).

CONCLUSION

Acupuncture can significantly improve the learning and memory damage caused by sleep deprivation and inhibit oxidative stress and autophagy, and its effect is related to the activation of AKT/mTOR signaling.

Longitudinal single-subject neuroimaging study reveals effects of daily environmental, physiological, and lifestyle factors on functional brain connectivity

Our behavior and mental states are constantly shaped by our environment and experiences. However, little is known about the response of brain functional connectivity to environmental, physiological, and behavioral changes on different timescales, from days to months. This gives rise to an urgent need for longitudinal studies that collect high-frequency data. To this end, for a single subject, we collected 133 days of behavioral data with smartphones and wearables and performed 30 functional magnetic resonance imaging (fMRI) scans measuring attention, memory, resting state, and the effects of naturalistic stimuli. We find traces of past behavior and physiology in brain connectivity that extend up as far as 15 days. While sleep and physical activity relate to brain connectivity during cognitively demanding tasks, heart rate variability and respiration rate are more relevant for resting-state connectivity and movie-watching. This unique data set is openly accessible, offering an exceptional opportunity for further discoveries. Our results demonstrate that we should not study brain connectivity in isolation, but rather acknowledge its interdependence with the dynamics of the environment, changes in lifestyle, and short-term fluctuations such as transient illnesses or restless sleep. These results reflect a prolonged and sustained relationship between external factors and neural processes. Overall, precision mapping designs such as the one employed here can help to better understand intraindividual variability, which may explain some of the observed heterogeneity in fMRI findings. The integration of brain connectivity, physiology data and environmental cues will propel future environmental neuroscience research and support precision healthcare.

Association between Enhanced Effective Connectivity from the Cuneus to the Middle Frontal Gyrus and Impaired Alertness after Total Sleep Deprivation

BACKGROUND

Sleep deprivation (SD) can impair an individual's alertness, which is the basis of attention and the mechanism behind continuous information processing. However, research concerning the effects of total sleep deprivation (TSD) on alertness networks is inadequate. In this study, we investigate the cognitive neural mechanism of alertness processing after TSD.

METHODS

Twenty-four college students volunteered to participate in the study. The resting-state electroencephalogram (EEG) data were collected under two conditions (rested wakefulness [RW], and TSD). We employed isolated effective coherence (iCoh) analysis and functional independent component analysis (fICA) to explore the effects of TSD on participants' alertness network.

RESULTS

This study found the existence of two types of effective connectivity after TSD, as demonstrated by iCoh: from the left cuneus to the right middle frontal gyrus in the β3 and γ bands, and from the left angular gyrus to the left insula in the δ, θ, α, β1, β3, and γ bands. Furthermore, Pearson correlation analysis showed that increased effective connectivity between all the bands had a positive correlation with increases in the response time in the psychomotor vigilance task (PVT). Finally, fICA revealed that the neural oscillations of the cuneus in the α2 bands increased, and of the angular gyrus in the α and β1 bands decreased in TSD.

CONCLUSIONS

TSD impairs the alertness function among individuals. Increased effective connectivity from the cuneus to the middle frontal gyrus may represent overloads on the alertness network, resulting in participants strengthening top-down control of the attention system. Moreover, enhanced effective connectivity from the angular gyrus to the insula may indicate a special perception strategy in which individuals focus on salient and crucial environmental information while ignoring inessential stimuli to reduce the heavy burden on the alertness network.

CLINICAL TRIAL REGISTRATION

No: ChiCTR2400088448. Registered 19 August 2024, https://www.chictr.org.cn.

Effects of perceived sleep quality on creative behavior via work engagement: the moderating role of gender

BACKGROUND

Sleep quality significantly impacts employees' attitudes and behaviors. Using ego depletion theory, we examined the influence of sleep quality on work engagement and creative behavior, also investigating gender differences in these effects.

METHODS

A multi-wave survey approach was employed with a six-week interval between waves for data collection. Participants were recruited online across two waves, totaling 322 employees from the United Kingdom and the United States.

RESULTS

Regression analyses revealed a statistically significant positive relationship between sleep quality and creative behavior, mediated by work engagement. Additionally, gender moderated both the direct and indirect effects of sleep quality.

CONCLUSION

The study found a positive relationship between sleep quality and creative behavior, mediated by work engagement, with notable gender differences. Sleep quality had a stronger impact on work engagement for men than women, and a stronger indirect effect on creative behavior through work engagement. These findings add to the existing literature on the influence of sleep quality on creative behavior.

Locus coeruleus microstructural integrity is associated with vigilance vulnerability to sleep deprivation

Insufficient sleep compromises cognitive performance, diminishes vigilance, and disrupts daily functioning in hundreds of millions of people worldwide. Despite extensive research revealing significant variability in vigilance vulnerability to sleep deprivation, the underlying mechanisms of these individual differences remain elusive. Locus coeruleus (LC) plays a crucial role in the regulation of sleep-wake cycles and has emerged as a potential marker for vigilance vulnerability to sleep deprivation. In this study, we investigate whether LC microstructural integrity, assessed by fractional anisotropy (FA) through diffusion tensor imaging (DTI) at baseline before sleep deprivation, can predict impaired psychomotor vigilance test (PVT) performance during sleep deprivation in a cohort of 60 healthy individuals subjected to a rigorously controlled in-laboratory sleep study. The findings indicate that individuals with high LC FA experience less vigilance impairment from sleep deprivation compared with those with low LC FA. LC FA accounts for 10.8% of the variance in sleep-deprived PVT lapses. Importantly, the relationship between LC FA and impaired PVT performance during sleep deprivation is anatomically specific, suggesting that LC microstructural integrity may serve as a biomarker for vigilance vulnerability to sleep loss.

Children's nocturnal awakenings and sleep duration during the first two years of life in the NASCITA cohort study

PURPOSE

Previous studies have analyzed the characteristics and prevalence of sleep disturbances among Italian children. Less attention has been paid, however, to the factors involved in sleep disturbances in the first two years of life. The goals of the present study were, therefore: 1) to provide a developmental trajectory of Italian infants' night awakenings and duration during the first two years of life and 2) to analyze which factors affect night awakenings the most over time.

METHODS

Data for this study were collected in the NASCITA cohort. During the well-child visits conducted at 6, 12, and 24 months, pediatricians asked parents to report if the child had any sleep disturbances, especially frequent night awakenings. Univariate and multivariable analyses were performed to test the association between child and family variables and the likelihood of frequent awakenings.

RESULTS

2973 toddlers, out of 5054 initially enrolled newborns, were included in this study; 875 (29.4 %) of whom presented frequent awakenings in at least one visit (peak of prevalence of 19.8 % at 12 months). Bed-sharing (adjusted OR 2.53; 95%CI:2.05-3.12) and living in the northern Italy (aOR 2.25; 95%CI:1.80-2.81) were the variables more strongly associated with an increased likelihood of frequent awakenings in the binomial logistic regression, while sleeping alone was associated with a decreased chance (aOR 0.62; 95%CI 0.45-0.89). A short sleep duration (<11 h/day) was reported for 801 (26.9 %) at 12 months, for 743 (25.0 %) at 24 months of age; in 383 cases, the short sleep duration was reported at both time points. An association was observed between frequent awakenings at 12 or 24 months and short sleep duration (OR 1.23; 95%CI 1.05-1.44 -ꭓ2 6.25, p = 0.012).

CONCLUSIONS

The current study identified some early predictors of frequent awakenings during the first two years of life. Since optimal sleep practices in children are essential for their development, effective, early interventions must be defined and integrated into pediatric care practices.

Behavioral and Electrophysiological Markers of Attention Fluctuations in Children with Hypersomnolence

Background. No device is yet available to effectively capture the attentional repercussions of hypersomnolence (HYP). The present study aimed to compare attentional performance of children with HYP, attention deficit hyperactivity disorder (ADHD), and controls using behavioral and electrophysiological (EEG) markers, and to assess their relationship with conventional sleepiness measurements. Methods. Children with HYP underwent a multiple sleep latency test (MSLT) and completed the adapted Epworth sleepiness scale (AESS). Along with age-matched children with ADHD, they were submitted to a resting EEG followed by the Bron-Lyon Attention Stability Test (BLAST). The control group only performed the BLAST. Multivariate models compared reaction time (RT), error percentage, BLAST-Intensity, BLAST-Stability, theta activity, and theta/beta ratio between groups. Correlations between these measures and conventional sleepiness measurements were conducted in children with HYP. Results. Children with HYP had lower RT and BLAST-Stability than controls but showed no significant difference in BLAST/EEG markers compared to children with ADHD. The AESS was positively correlated with the percentage of errors and negatively with BLAST-Intensity. Conclusions. Children with HYP showed impulsivity and attention fluctuations, without difference from children with ADHD for BLAST/EEG markers. The BLAST-EEG protocol could be relevant for the objective assessment of attentional fluctuations related to hypersomnolence.

The Mixed Role of Sleep and Time of Day in Working Memory Performance of Older Adults with Mild Cognitive Impairment

The importance of night sleep for maintaining good physical and cognitive health is well documented as well as its negative changes during aging. Since Mild Cognitive Impairment (MCI) patients bear additional disturbances in their sleep, this study aimed at examining whether there are potential mixed effects of sleep and afternoon time of day (ToD) on the storage, processing, and updating components of working memory (WM) capacity in older adults with MCI. In particular, the study compared patients' performance in the three working memory components, in two-time conditions: "early in the morning and after night sleep", and "in the afternoon and after many hours since night sleep". The Working Memory Capacity & Updating Task from the R4Alz battery was administered twice to 50 older adults diagnosed with MCI. The repeated measures analysis showed statistically significant higher performance in the morning condition for the working memory updating component (p < 0.001). Based on the findings, it seems that the afternoon ToD condition negatively affects tasks with high cognitive demands such as the WM updating task in MCI patients. These findings could determine the optimal timing for cognitive rehabilitation programs for MCI patients and the necessary sleep duration when they are engaged in cognitively demanding daily activities.

Sleep Deprivation Effects on Brain State Dynamics Are Associated With Dopamine D2 Receptor Availability Via Network Control Theory

BACKGROUND

Sleep deprivation (SD) negatively affects brain function. Most brain imaging studies have investigated the effects of SD on static brain function. SD effects on functional brain dynamics and their relationship with molecular changes remain relatively unexplored.

METHODS

We used functional magnetic resonance imaging to examine resting-brain state dynamics after one night of SD compared with rested wakefulness (N = 41) and assessed the association of brain state dynamics with striatal brain dopamine D2 receptor availability measured by positron emission tomography [11C]raclopride using network control theory.

RESULTS

SD reduced dwell time and persistence probabilities, with the strongest effects in two brain states, one characterized by high default mode network and low dorsal attention network activity and the other by high frontoparietal network and low somatomotor network activity. Using network control theory, we showed that after SD, there was an overall increase in the control energy required for brain state transitions, with effects varying for different brain state transitions. Control energy requirement was negatively associated with transition probabilities under SD and restful wakefulness and accounted for SD-induced changes in transition probabilities. Alteration in the energy landscape was associated with SD-induced changes in striatal D2 receptor distribution.

CONCLUSIONS

These findings demonstrate altered occurrence of internally and externally oriented brain states following acute SD and suggest an association with energy requirements for brain state transitions modulated by striatal D2 receptors.

Biomathematical modeling of fatigue due to sleep inertia

Biomathematical models of fatigue capture the physiology of sleep/wake regulation and circadian rhythmicity to predict changes in neurobehavioral functioning over time. We used a biomathematical model of fatigue linked to the adenosinergic neuromodulator/receptor system in the brain as a framework to predict sleep inertia, that is, the transient neurobehavioral impairment experienced immediately after awakening. Based on evidence of an adenosinergic basis for sleep inertia, we expanded the biomathematical model with novel differential equations to predict the propensity for sleep inertia during sleep and its manifestation after awakening. Using datasets from large laboratory studies of sleep loss and circadian misalignment, we calibrated the model by fitting just two new parameters and then validated the model's predictions against independent data. The expanded model was found to predict the magnitude and time course of sleep inertia with generally high accuracy. Analysis of the model's dynamics revealed a bifurcation in the predicted manifestation of sleep inertia in sustained sleep restriction paradigms, which reflects the observed escalation of the magnitude of sleep inertia in scenarios with sleep restriction to less than ∼ 4 h per day. Another emergent property of the model involves a rapid increase in the predicted propensity for sleep inertia in the early part of sleep followed by a gradual decline in the later part of the sleep period, which matches what would be expected based on the adenosinergic regulation of non-rapid eye movement (NREM) sleep and its known influence on sleep inertia. These dynamic behaviors provide confidence in the validity of our approach and underscore the predictive potential of the model. The expanded model provides a useful tool for predicting sleep inertia and managing impairment in 24/7 settings where people may need to perform critical tasks immediately after awakening, such as on-demand operations in safety and security, emergency response, and health care.

Assessing the influence of sleep and sampling time on metabolites in oral fluid: implications for metabolomics studies

INTRODUCTION

The human salivary metabolome is a rich source of information for metabolomics studies. Among other influences, individual differences in sleep-wake history and time of day may affect the metabolome.

OBJECTIVES

We aimed to characterize the influence of a single night of sleep deprivation compared to sufficient sleep on the metabolites present in oral fluid and to assess the implications of sampling time points for the design of metabolomics studies.

METHODS

Oral fluid specimens of 13 healthy young males were obtained in Salivette® devices at regular intervals in both a control condition (repeated 8-hour sleep) and a sleep deprivation condition (total sleep deprivation of 8 h, recovery sleep of 8 h) and their metabolic contents compared in a semi-targeted metabolomics approach.

RESULTS

Analysis of variance results showed factor 'time' (i.e., sampling time point) representing the major influencer (median 9.24%, range 3.02-42.91%), surpassing the intervention of sleep deprivation (median 1.81%, range 0.19-12.46%). In addition, we found about 10% of all metabolic features to have significantly changed in at least one time point after a night of sleep deprivation when compared to 8 h of sleep.

CONCLUSION

The majority of significant alterations in metabolites' abundances were found when sampled in the morning hours, which can lead to subsequent misinterpretations of experimental effects in metabolomics studies. Beyond applying a within-subject design with identical sample collection times, we highly recommend monitoring participants' sleep-wake schedules prior to and during experiments, even if the study focus is not sleep-related (e.g., via actigraphy).

Impact of chronic sleep deprivation on male reproductive health: Insights from testicular and epididymal responses in mice

BACKGROUND

Sleep deprivation (SD) can cause damage to the male reproductive system. However, the duration required for such damage and the specific sequence and severity of damage to the testis and epididymis remain unclear.

OBJECTIVE

To investigate the effects of different durations of SD on different parts of the testis and epididymis caput, corpus, and cauda.

METHODS

Adult ICR mice were randomly assigned to five groups: the SD group (SD for 18 h/day for 1, 2, 3, or 4 weeks), the SD + Vit E group (supplemented with Vit E 50 mg/kg/d during 4 weeks of SD, the SD+NS group (saline supplementation during 4 weeks of SD), the SD + RS group (5 weeks of recovery sleep after 4 weeks of SD), and a normal sleep control (Ctrl) group. Following the interventions, sperm parameters, testicular and epididymal histopathology, inflammatory response, and oxidative stress markers were compared between the groups.

RESULTS

Compared to the Ctrl group, the SD group showed a decrease in sperm motility and concentration from SD 2 W and SD 3 W, respectively. Decreases in sperm concentration and motility were more pronounced in the cauda compared to the caput and corpus. Pathological damage was less severe in the epididymis caput than in the corpus and cauda. After 4 weeks of SD, inflammation and oxidative stress increased in both testes and epididymis. Both sleep recovery and vitamin E supplementation showed significant improvements, though they did not fully reach the level of the Ctrl group.

CONCLUSION

Chronic SD for more than 2 weeks causes varying degrees of damage to the testis, epididymis caput, corpus, and cauda in male mice. This damage is not fully reversible after 5 weeks of sleep recovery and antioxidant stress treatment. These findings help us to identify and prevent SD damage to the male reproduction at an early stage.

Long-term influence of sleep/wake history on the dynamic neurobehavioural response to sustained sleep restriction

Chronic sleep restriction, common in today's 24/7 society, causes cumulative neurobehavioural impairment, but the dynamics of the build-up and dissipation of this impairment have not been fully elucidated. We addressed this knowledge gap in a laboratory study involving two, 5-day periods of sleep restriction to 4 hr per day, separated by a 1-day dose-response intervention sleep opportunity. We measured sleep physiological and waking neurobehavioural responses in 70 healthy adults, each randomized to one of seven dose-response intervention sleep doses ranging from 0 to 12 hr, or a non-sleep-restricted control group. As anticipated, sleep physiological markers showed homeostatic dynamics throughout the study, and waking neurobehavioural impairment accumulated across the two sleep restriction periods. Unexpectedly, there was only a slight and short-lived effect of the 1-day dose-response intervention sleep opportunity. Whether the dose-response intervention sleep opportunity involved extension, further restriction or total deprivation of sleep, neurobehavioural functioning during the subsequent second sleep restriction period was dominated by prior sleep-wake history. Our findings revealed a profound and enduring influence of long-term sleep-wake history as a fundamental aspect of the dynamic regulation of the neurobehavioural response to sleep loss.

Can stimulants make you smarter, despite stealing your sleep?

Nonmedical use of psychostimulants for cognitive enhancement is widespread and growing in neurotypical individuals, despite mixed scientific evidence of their effectiveness. Sleep benefits cognition, yet the interaction between stimulants, sleep, and cognition in neurotypical adults has received little attention. We propose that one effect of psychostimulants, namely decreased sleep, may play an important and unconsidered role in the effect of stimulants on cognition. We discuss the role of sleep in cognition, the alerting effects of stimulants in the context of sleep loss, and the conflicting findings of stimulants for complex cognitive processes. Finally, we hypothesize that sleep may be one unconsidered factor in the mythology of stimulants as cognitive enhancers and propose a methodological approach to systematically assess this relation.

Altered Functional Connectivity of the Thalamus Subregions Associated with Impaired Attention After Sleep Deprivation

Objective

The thalamus plays a critical role in attentional maintenance. Previous studies have revealed the dysfunction of the thalamus in attention decline after acute sleep deprivation (SD). However, the functional connectivity (FC) between the thalamus subregions and cortical regions underlying attentional impairment after acute SD remains unclear. Here, we aimed to probe the relationship between attentional function and the altered thalamocortical FC after acute SD.

Methods

In this study, 25 healthy participants with regular sleep conducted an attentional network test and received a resting-state fMRI scan before and after 24 hours of SD. Then, we analyzed the FC between the thalamus and cerebrum and relationships with attentional function in the enrolled subjects.

Results

Our results showed that the participants showed a significantly lower alerting effect, a higher executive effect, and lower accuracy after acute SD. Compared to the rested wakefulness state, we observed decreased FCs between the "somatosensory" thalamic seed and left frontal pole, right frontal pole, left middle temporal gyrus (posterior division), and right middle temporal gyrus (posterior division). Furthermore, the reduced FC between the right middle temporal gyrus and "somatosensory" thalamic seed was negatively associated with the change in orienting effect of the participants.

Conclusion

Our findings reveal that the disrupted FC between thalamus subregions and cortical regions may contribute to impaired attention after SD.

Effect of L-theanine on selective attention in a traffic-related reaction task in sleep-deprived young adults: a double-blind placebo-controlled, crossover study

BACKGROUND

L-theanine is a non-protein-forming amino acid found in tea. Limited evidence suggests that it improves selective attention. Sleep deprivation impairs attention and psychomotor reactions, affecting automobile driving. We aimed to determine whether L-theanine improves neurobehavioral measures of visual attention in acutely sleep-deprived healthy adults in a traffic-scene-based attention task.

METHODS

In a double-blind, placebo-controlled, counterbalanced, two-way crossover study, we compared the effects of a 200-mg dose of L-theanine with a placebo (150 ml of distilled water) on a computerised, traffic-scene-based visual recognition reaction task in 24 healthy volunteers (age 20-25 years; 13 males) sleep-deprived overnight. The participants made speeded button-presses to imminent accident scenes (i.e. hits), while ignoring safe scenes. They were tested pre-dose and 45 min post-dose, each treatment administered one week apart.

RESULTS

Hit rates were more than 90% in all sessions, and were similar in two treatments, pre- vs post-dose. L-theanine significantly reduced false alarms (i.e. responses to safe scenes) (p = 0.014) and increased A' (i.e. target-distractor discriminability) (p = 0.009), whereas placebo did not (p > 0.05). L-theanine reduced hit reaction time by 38.65 ms (p = 0.007), and placebo by 19.08 ms (p = 0.016), however reaction time changes from baseline were not significantly different between treatments (p > 0.05).

CONCLUSIONS

L-theanine in high doses appears to improve selective visual attention by concurrently improving information processing speed and target-distractor discriminability in acutely sleep-deprived individuals. This is consistent with previous functional neuroimaging findings, where L-theanine suppressed distractor-processing and default-mode-network activity in visual selective attention tasks.

A multidimensional investigation of sleep and biopsychosocial profiles with associated neural signatures

Sleep is essential for optimal functioning and health. Interconnected to multiple biological, psychological and socio-environmental factors (i.e., biopsychosocial factors), the multidimensional nature of sleep is rarely capitalized on in research. Here, we deployed a data-driven approach to identify sleep-biopsychosocial profiles that linked self-reported sleep patterns to inter-individual variability in health, cognition, and lifestyle factors in 770 healthy young adults. We uncovered five profiles, including two profiles reflecting general psychopathology associated with either reports of general poor sleep or an absence of sleep complaints (i.e., sleep resilience) respectively. The three other profiles were driven by the use of sleep aids and social satisfaction, sleep duration and cognitive performance, and sleep disturbance linked to cognition and mental health. Furthermore, identified sleep-biopsychosocial profiles displayed unique patterns of brain network organization. In particular, somatomotor network connectivity alterations were involved in the relationships between sleep and biopsychosocial factors. These profiles can potentially untangle the interplay between individuals' variability in sleep, health, cognition and lifestyle - equipping research and clinical settings to better support individual's well-being.

Fluctuation in cortical excitation/inhibition modulates capability of attention across time scales ranging from hours to seconds

Sustained attention, as the basis of general cognitive ability, naturally varies across different time scales, spanning from hours, e.g. from wakefulness to drowsiness state, to seconds, e.g. trial-by-trail fluctuation in a task session. Whether there is a unified mechanism underneath such trans-scale variability remains unclear. Here we show that fluctuation of cortical excitation/inhibition (E/I) is a strong modulator to sustained attention in humans across time scales. First, we observed the ability to attend varied across different brain states (wakefulness, postprandial somnolence, sleep deprived), as well as within any single state with larger swings. Second, regardless of the time scale involved, we found highly attentive state was always linked to more balanced cortical E/I characterized by electroencephalography (EEG) features, while deviations from the balanced state led to temporal decline in attention, suggesting the fluctuation of cortical E/I as a common mechanism underneath trans-scale attentional variability. Furthermore, we found the variations of both sustained attention and cortical E/I indices exhibited fractal structure in the temporal domain, exhibiting features of self-similarity. Taken together, these results demonstrate that sustained attention naturally varies across different time scales in a more complex way than previously appreciated, with the cortical E/I as a shared neurophysiological modulator.

The impact of REM sleep loss on human brain connectivity

Brain function is vulnerable to the consequences of inadequate sleep, an adverse trend that is increasingly prevalent. The REM sleep phase has been implicated in coordinating various brain structures and is hypothesized to have potential links to brain variability. However, traditional imaging research have encountered challenges in attributing specific brain region activity to REM sleep, remained understudied at the whole-brain connectivity level. Through the spilt-night paradigm, distinct patterns of REM sleep phases were observed among the full-night sleep group (n = 36), the early-night deprivation group (n = 41), and the late-night deprivation group (n = 36). We employed connectome-based predictive modeling (CPM) to delineate the effects of REM sleep deprivation on the functional connectivity of the brain (REM connectome) during its resting state. The REM sleep-brain connectome was characterized by stronger connectivity within the default mode network (DMN) and between the DMN and visual networks, while fewer predictive edges were observed. Notably, connections such as those between the cingulo-opercular network (CON) and the auditory network, as well as between the subcortex and visual networks, also made significant contributions. These findings elucidate the neural signatures of REM sleep loss and reveal common connectivity patterns across individuals, validated at the group level.

Propofol improves sleep deprivation-induced sleep structural and cognitive deficits via upregulating the BMAL1 expression and suppressing microglial M1 polarization

BACKGROUND

Sleep deprivation (SD) is a growing global health problem with many deleterious effects, such as cognitive impairment. Microglia activation-induced neuroinflammation may be an essential factor in this. Propofol has been shown to clear sleep debt after SD in rats. This study aims to evaluate the effects of propofol-induced sleep on ameliorating sleep quality impairment and cognitive decline after 48 h SD.

METHODS

Almost 8-12-week-old rats were placed in the SD system for 48 h of natural sleep or continuous SD. Afterwards, rats received propofol (20 mg·kg-1·h-1, 6 h) via the tail or slept naturally. The Morris water maze (MWM) and Y-maze test assessed spatial learning and memory abilities. Rat EEG/EMG monitored sleep. The expression of brain and muscle Arnt-like protein 1 (BMAL1), brain-derived neurotrophic factor (BDNF) in the hippocampus and BMAL1 in the hypothalamus were assessed by western blot. Enzyme-linked immunosorbent assay detected IL-6, IL-1β, arginase 1 (Arg1), and IL-10 levels in the hippocampus. Immunofluorescence was used to determine microglia expression as well as morphological changes.

RESULTS

Compared to the control group, the sleep-deprived rats showed poor cognitive performance on both the MWM test and the Y-maze test, accompanied by disturbances in sleep structure, including increased total sleep time, and increased time spent and delta power in non-rapid eye movement sleep. In addition, SD induces abnormal expression of the circadian rhythm protein BMAL1, activates microglia, and causes neuroinflammation and nerve damage. Propofol reversed these changes and saved sleep and cognitive impairment. Furthermore, propofol treatment significantly reduced hippocampal IL-1β and IL-6 levels, increased BDNF, Arg1, and IL-10 levels, and switched microglia surface markers from the inflammatory M1 type to the anti-inflammatory M2 type.

CONCLUSION

Propofol reduces SD-induced cognitive impairment and circadian rhythm disruption, possibly by lowering neuronal inflammation and switching the microglia phenotype from an M1 to an M2 activated state, thus exerting neuroprotective effects.

Nighttime Treatment of Ruptured Intracranial Aneurysms Are Associated With Poor Outcomes

BACKGROUND AND OBJECTIVES

Rebleeding of ruptured intracranial aneurysms (RIA) is associated with poor outcomes. Although immediate treatment of RIAs is preferred, optimal treatment timing is multifactorial and may be a complicating factor for achieving the best outcomes. The objective of this study was to compare outcomes for patients with RIAs as a function of treatment time of day. To the best of our knowledge, this is the first study that examines how treatment time of day influences treatment outcomes.

METHODS

This retrospective single-center study included all patients who were treated, either surgically or endovascularly, for RIAs within 24 hours after admission. Exclusion criteria were blister, mycotic or giant aneurysms, or incomplete records. The modified Rankin Scale was used to evaluate treatment outcomes using multivariate analysis. Nighttime treatment was defined when greater than 50% of the procedure was performed between 10 pm and 7 am, with other times classified as daytime treatment. Off-hours treatment was defined when more than 50% of the procedure was performed between 7 pm and 7 am, with other times classified as on-hours.

RESULTS

This study included 493 patients, with 84.2% (415) treated during the daytime, 15.8% (78) during the nighttime, 67.5% (333) during on-hours, and 32.5% (160) during off-hours. These groups did not differ according to age, sex, World Federation of Neurosurgical Societies and Fisher scales, aneurysm size, location, and surgical or endovascular treatment. Outcomes were favorable (modified Rankin Scale 0-2) for 72.0% (299) of patients treated during the daytime and 60.0% (46) of patients treated during the nighttime. Aneurysm treatment during the nighttime (OR: 0.50 [95% CI: 0.28-0.91], P = .023) but not during off-hours (OR: 0.76 [0.50-1.14], P = .18) was independently associated with unfavorable outcomes.

CONCLUSION

Nighttime treatment was associated with poorer outcomes. Further studies are needed to evaluate outcomes if treatment is postponed to daytime hours.

Hilaire MA, Arrona-Palacios A, Czeisler CA, Duffy JF. Time of Day and Sleep Deprivation Effects on Risky Decision Making

Previous research has revealed that daily variations in human neurobehavioral functions are driven in part by the endogenous circadian system. The objective of this study was to explore whether there exists a circadian influence on performance regarding a risky decision-making task and to determine whether the performance changes with sleep deprivation (SD). Thirteen participants underwent a 39 h constant routine (CR) protocol, during which they remained awake in constant conditions and performed the BART (balloon analogue risk task) every two hours. The mean pumps (gains) (p < 0.001) and balloons popped (losses) (p = 0.003) exhibited variation during the CR. The reaction time (RT) also showed significant variation across the CR (p < 0.001), with slower mean RTs in the morning hours following SD. A greater risk propensity was observed around midday before SD and a lower risk propensity after 29.5 h of being awake. The sensitivity to punishment varied during the CR, but did not follow a predictable trend. Further research using real monetary incentives and neurophysiological measures is warranted to elucidate these findings.

Alteration in neural oscillatory activity and phase-amplitude coupling after sleep deprivation: Evidence for impairment and compensation effects

Insufficient sleep can significantly affect vigilance and increase slow-wave electroencephalographic power as homeostatic sleep pressure accumulates. Phase-amplitude coupling is involved in regulating the spatiotemporal integration of physiological processes. This study aimed to examine the functional associations of resting-state electroencephalographic power and delta/theta-gamma phase-amplitude coupling from the prefrontal cortex (PFC) to posterior regions with vigilance performance after sleep deprivation. Forty-six healthy adults underwent 24-hr sleep deprivation with resting-state electroencephalographic recordings, and vigilant attention was measured using the Psychomotor Vigilance Task. Power spectral and phase-amplitude coupling analyses were conducted, and correlation analysis was utilized to reveal the relationship between electroencephalographic patterns and changes in vigilance resulting from sleep deprivation. Sleep deprivation significantly declined vigilance performance, accompanied by increased resting-state electroencephalographic power in all bands and delta/theta-gamma phase-amplitude coupling. The increased theta activity in centro-parieto-occipital areas significantly correlated with decreased mean and slowest response speed. Conversely, the increased delta-low gamma and theta-high gamma phase-amplitude couplings negatively correlated with the deceleration of the fastest Psychomotor Vigilance Task reaction times. These findings suggest that sleep deprivation affects vigilance by altering electroencephalographic spectral power and information communication across frequency bands in different brain regions. The distinct effects of increased theta power and delta/theta-gamma phase-amplitude coupling might reflect the impairment and compensation of sleep deprivation on vigilance performance, respectively.

Development of sleepiness in professional truck drivers: Real-road testing for driver drowsiness and attention warning (DDAW) system evaluation

All new vehicle types within the European Union must now be equipped with a driver drowsiness and attention warning system starting from 2022. The specific requirements for the test procedure necessary for type approval are defined in the Annex of EU Regulation C/2021/2639. The objectives of this study were to: (i) investigate how sleepiness develops in professional truck drivers under real-road driving conditions; and (ii) assess the feasibility of a test procedure for validating driver drowsiness and attention warning systems according to the EU regulation. Twenty-four professional truck drivers participated in the test. They drove for 180 km on a dual-lane motorway, first during daytime after a normal night's sleep and then at nighttime after being awake since early morning. The results showed higher sleepiness levels during nighttime driving compared with daytime, with a faster increase in sleepiness with distance driven, especially during the night. Psychomotor vigilance task results corroborated these findings. From a driver drowsiness and attention warning testing perspective, the study design with sleep-deprived drivers at night was successful in inducing the targeted sleepiness level of a Karolinska Sleepiness Scale score of ≥ 8. Many drivers who reported a Karolinska Sleepiness Scale ≥ 8 during the drives also acknowledged feeling sleepy in the post-drive questionnaire. Reaching high levels of sleepiness on real roads during daytime is more problematic, not the least from legal and ethical perspectives as higher traffic densities during the daytime lead to increased risks.

Sleep quality among patients with chronic illness in Ethiopia: systematic review and meta-analysis

Background

Poor sleep quality impedes the progression of chronic illnesses, while chronic illnesses themselves are caused by poor sleep quality. Despite this fact, there is no research that has been conducted in Ethiopia that provides a thorough estimate of the self-reported sleep quality among patients with chronic illnesses. In order to present a complete picture of poor sleep quality among diabetes, hypertension, heart failure, cancer, HIV/AIDS and epilepsy patients, this systematic review and meta-analysis was carried out.

Methods

Systematic review and meta-analysis was conducted to estimate the quality of sleep among patients with chronic illness in Ethiopia. The Preferred Reporting Items for Systematic Review and Meta Analysis standard was followed in the reporting of this systematic review and meta-analysis. An extensive exploration of digital repositories, including PubMed, EMBASE, Cochrane, Africa Journal of Online, Google Scholar, and an advanced Google search, was conducted to obtain published studies until December 1st, 2023 detailing poor sleep quality of patients with chronic illness. STATA version 17 commands were used to create the pooled estimate. The I2 test and Egger's test, respectively, were used to identify the presence of heterogeneity and publication bias. To manage heterogeneity, a subgroup analysis and random effect model were used.

Results

A total 21 articles with a total of 7393 participants were included in the final systematic review and meta-analysis. The pooled estimate of poor sleep quality among patients with chronic illness was 52% (95% of CI: 48%, 59%; I2 = 97.26%). In subgroup analysis, the highest pooled estimate of poor sleep quality was observed in cancer patients 63% (95% CI: (95% CI: 45% - 80%). Regarding to data collection period, the highest pooled estimate of poor sleep quality was seen during spring 68% (95% CI: 42% - 94%).

Conclusions

Patients with chronic illnesses in Ethiopia had a high pooled estimate of poor sleep quality. Patients with cancer had the highest pooled estimate of poor-quality sleep compared with other patients. Patients with chronic illnesses had trouble sleeping in the spring, according to this systematic review and meta-analysis. Therefore, attention and intervention should be given to enhance the quality of sleep for patients with chronic illnesses.

Guhan Yangsheng Jing mitigates hippocampal neuronal pyroptotic injury and manifies learning and memory capabilities in sleep deprived mice via the NLRP3/Caspase1/GSDMD signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Guhan Yangsheng Jing (GHYSJ) is a traditional Chinese patent medicine, that has the function of nourishing the kidney and replenishing the essence, invigorating the brain and calming the mind. It is often used to treat dizziness, memory loss, sleep disorders, fatigue, and weakness, etc. However, its mechanism for improving sleep has not yet been determined.

AIM OF THE STUDY

This study aims to explore the effects of GHYSJ on Sleep Deprivation (SD)-induced hippocampal neuronal pyroptotic injury, learning and cognitive abilities, and sleep quality in mice.

METHODS

In this study, a PCPA-induced SD mouse model was established. We assessed the influence of GHYSJ on sleep quality and mood by using the pentobarbital-induced sleep test (PIST) and sucrose preference test (SPT). The pharmacological effects of GHYSJ on learning and memory impairment were evaluated by the Morris Water Maze (MWM) and Open Field Test (OFT). Pathological changes in the hippocampal tissue of the SD rats were observed via HE staining and Nissl staining. The severity of neuronal damage was evaluated by detecting the expression of the neuronal marker Microtubule-associated protein 2 (MAP2), via immunohistochemistry and immunofluorescence. Furthermore, the levels of neurotransmitter 5-hydroxytryptophan (5-HTP), 5-hydroxy tryptamine (5-HT), γ-aminobutyric acid (GABA), and Glutamic acid (Glu) in hippocampal tissues, as well as the expression of inflammatory factors Interleukin-1β (IL-1β) and Interleukin-18 (IL-18) in serum, were determined by ELISA. The expressions of mRNA and protein NOD-like receptor thermal protein domain associated protein 3 (NLRP3), Gasdermin D (GSDMD), Cysteinyl aspartate specific proteinase1 (Caspase1), High mobility group box-1 protein (HMGB1) and Apoptosis-associated speck-like protein containing CARD (ASC) related to the cellular ferroptosis pathway were tested and analyzed by RT-PCR and WB respectively.

RESULTS

PCPA significantly diminishes the sleep span of experimental animals by expediting the expenditure of 5-HT, consequently establishing an essentially direct SD model. The intervention of GHYSJ displays remarkable efficacy in mitigating insomnia symptoms, encompassing difficulties in initiating sleep and insufficient sleep duration. Likewise, it ameliorates memory function impairments induced by sleep deprivation, along with symptoms such as fatigue and depletion of vitality. GHYSJ exerts a protective influence on hippocampal neurons facilitated by inhibiting the down regulation of MAP2 and maintaining the equilibrium of neurotransmitters (5-HTP, 5-HT, GABA, and Glu). It diminishes the expression of intracellular pyroptosis-associated inflammatory factors (IL-1β and IL-18) and curbs the activation of the NLRP3/Caspase1/GSDMD pyroptosis-related signaling pathways, thereby alleviating the damage caused by hippocampal neuronal pyroptosis.

Chronic short sleep duration lengthens reaction time, but the deficit is not associated with motor preparation

The purpose of this study was to investigate the association between chronic sleep duration and reaction time performance and motor preparation during a simple reaction time task with a startling acoustic stimulus in adults. This cross-sectional study included self-reported short sleepers (n = 25, ≤ 6 hr per night) and adequate sleepers (n = 25, ≥ 7.5 hr per night) who performed a simple reaction time task requiring a targeted ballistic wrist extension in response to either a control-tone (80 dB) or a startling acoustic stimulus (120 dB). Outcome measures included reaction times for each stimulus (overall and for each trial block), lapses, and proportion of startle responses. Chronic short sleepers slept on average 5.7 hr per night in the previous month, which was 2.8 hr per night less than the adequate sleepers. Results revealed an interaction between sleep duration group and stimulus type; the short sleepers had significantly slower control-tone reaction times compared with adequate sleepers, but there was no significant difference in reaction time between groups for the startling acoustic stimulus. Further investigation showed that chronic short sleepers had significantly slower control-tone reaction times after two blocks of trials lasting about 5 min, until the end of the task. Lapses were not significantly different between groups. Chronic short sleep duration was associated with poorer performance; however, these reaction time deficits cannot be attributed to motor preparation, as startling acoustic stimulus reaction times were not different between sleep duration groups. While time-on-task performance decrements were associated with chronic sleep duration, alertness was not. Sleeping less than the recommended sleep duration on a regular basis is associated with poorer cognitive performance, which becomes evident after 5 min.

Emergent effects of synaptic connectivity on the dynamics of global and local slow waves in a large-scale thalamocortical network model of the human brain

Slow-wave sleep (SWS), characterized by slow oscillations (SO, <1Hz) of alternating active and silent states in the thalamocortical network, is a primary brain state during Non-Rapid Eye Movement (NREM) sleep. In the last two decades, the traditional view of SWS as a global and uniform whole-brain state has been challenged by a growing body of evidence indicating that SO can be local and can coexist with wake-like activity. However, the understanding of how global and local SO emerges from micro-scale neuron dynamics and network connectivity remains unclear. We developed a multi-scale, biophysically realistic human whole-brain thalamocortical network model capable of transitioning between the awake state and slow-wave sleep, and we investigated the role of connectivity in the spatio-temporal dynamics of sleep SO. We found that the overall strength and a relative balance between long and short-range synaptic connections determined the network state. Importantly, for a range of synaptic strengths, the model demonstrated complex mixed SO states, where periods of synchronized global slow-wave activity were intermittent with the periods of asynchronous local slow-waves. Increase of the overall synaptic strength led to synchronized global SO, while decrease of synaptic connectivity produced only local slow-waves that would not propagate beyond local area. These results were compared to human data to validate probable models of biophysically realistic SO. The model producing mixed states provided the best match to the spatial coherence profile and the functional connectivity estimated from human subjects. These findings shed light on how the spatio-temporal properties of SO emerge from local and global cortical connectivity and provide a framework for further exploring the mechanisms and functions of SWS in health and disease.

Impact of a structured sleep education program on mothers' knowledge and attitudes toward infant sleeping

Introduction

Sleeping is necessary for the infant growth and development. Sufficient and quality of sleep can have an impact on physical, cognitive, and emotional functioning. Infancy is a critical time for establishing healthy habits and routines. However, many infants were suffering from sleeping issues that impact their health.

Objectives

This study aims to evaluate the effect of educational programs given to mothers regarding their infants' sleep on mothers' knowledge and attitudes toward infant's sleeping.

Method

A quasi-experimental design for nonequivalent groups was used, and data was collected from 208 mothers with infants aged 5-12 months from all Jordanian governorates who had not been exposed to educational programs prior to this study. Data was collected in two stages: pre-test and post-test, with two weeks in between for both groups.

Results

The final results indicated that the educational intervention had a significant impact on mothers' knowledge over time. It was found that mothers in the intervention group had significantly higher mean of infant sleep health knowledge at follow up time compared to their baseline time (B = 0.236, P 0.001). Also, the yielded analysis showed that there was no significant change in mothers' mean attitudes toward infants sleeping over time (P = 0.011). The mothers' measured sleep health knowledge correlated positively and significantly statistically with their sleep health attitudes score (r = 0.436, P 0.010).

Sleep deprivation changes frequency-specific functional organization of the resting human brain

Previous resting-state functional magnetic resonance imaging (rs-fMRI) studies have widely explored the temporal connection changes in the human brain following long-term sleep deprivation (SD). However, the frequency-specific topological properties of sleep-deprived functional networks remain virtually unclear. In this study, thirty-seven healthy male subjects underwent resting-state fMRI during rested wakefulness (RW) and after 36 hours of SD, and we examined frequency-specific spectral connection changes (0.01-0.08 Hz, interval = 0.01 Hz) caused by SD. First, we conducted a multivariate pattern analysis combining linear SVM classifiers with a robust feature selection algorithm, and the results revealed that accuracies of 74.29%-84.29% could be achieved in the classification between RW and SD states in leave-one-out cross-validation at different frequency bands, moreover, the spectral connection at the lowest and highest frequency bands exhibited higher discriminative power. Connection involving the cingulo-opercular network increased most, while connection involving the default-mode network decreased most following SD. Then we performed a graph-theoretic analysis and observed reduced low-frequency modularity and high-frequency global efficiency in the SD state. Moreover, hub regions, which were primarily situated in the cerebellum and the cingulo-opercular network after SD, exhibited high discriminative power in the aforementioned classification consistently. The findings may indicate the frequency-dependent effects of SD on the functional network topology and its efficiency of information exchange, providing new insights into the impact of SD on the human brain.

Latent profile analysis of depression in US adults with obstructive sleep apnea hypopnea syndrome

Objective

This study used latent profile analysis to explore the level of depression among US adults with obstructive sleep apnea hypopnea syndrome (OSAHS) symptoms and to identify different latent categories of depression to gain insight into the characteristic differences between these categories.

Methods

The data of this study were obtained from the National Health and Nutrition Examination Survey (NHANES) database, and the subjects with OSAHS symptoms were aged 18 years and older. The latent profile analysis (LPA) method was used to fit the latent depression categories in subjects with OSAHS symptoms. The chi-square test, rank sum test, and binary logistic regression were used to analyze the influencing factors of depression subgroups in subjects with OSAHS symptoms.

Results

Three latent profiles were identified: low-level (83.7%), moderate-level (14.5%) and high-level (1.8%) depression. The scores of 9 items in the high-level depression group were higher than those in the other two groups. Among them, item 4 "feeling tired or lack of energy" had the highest score in all categories.

Conclusion

Depression in subjects with OSAHS symptoms can be divided into low-level, moderate-level and high-level depression. There are significant differences among different levels of depression in gender, marital status, PIR, BMI, smoking, general health condition, sleep duration and OSAHS symptom severity.

A resting-state EEG dataset for sleep deprivation

To investigate the impact of sleep deprivation (SD) on mood, alertness, and resting-state electroencephalogram (EEG), we present an eyes-open resting-state EEG dataset. The dataset comprises EEG recordings and cognitive data from 71 participants undergoing two testing sessions: one involving SD and the other normal sleep. In each session, participants engaged in eyes-open resting-state EEG. The Psychomotor Vigilance Task (PVT) was employed for alertness measurement. Emotional and sleepiness were measured using Positive and Negative Affect Scale (PANAS) and Stanford Sleepiness Scale (SSS). Additionally, to examine the influence of individual sleep quality and traits on SD, Pittsburgh Sleep Quality Index (PSQI) and Buss-Perry Aggression Questionnaire (BPAQ) were utilized. This dataset's sharing may contribute to open EEG measurements in the field of SD.

Olfactory Epithelium Stimulation Using Rhythmic Nasal Air-Puffs Improves the Cognitive Performance of Individuals with Acute Sleep Deprivation

This study aimed to investigate the effects of intranasal air-puffing on cognitive impairments and brain cortical activity following one night of partial sleep deprivation (PSD) in adults. A total of 26 healthy adults underwent the numerical Stroop test (NST) and electroencephalography (EEG) before and after one night of PSD. Following PSD, subjects in the treatment group (n = 13) received nasal air-puffs (5 Hz, 3 min) before beginning the NST and EEG recording. Administration of nasal air-puffs in the treatment group restored the PSD-induced increase in error rate and decrease in reaction time and missing rate in the NST. Intranasal air-puffs recovered the PSD-induced augmentation of delta and theta power and the reduction of beta and gamma power in the EEG, particularly in the frontal lobes. Intranasal air-puffing also almost reversed the PSD-induced decrease in EEG signal complexity. Furthermore, it had a restorative effect on PSD-induced alteration in intra-default mode network functional connectivity in the beta and gamma frequency bands. Rhythmic nasal air-puffing can mitigate acute PSD-induced impairments in cognitive functions. It exerts part of its ameliorating effect by restoring neuronal activity in cortical brain areas involved in cognitive processing.

A multidimensional investigation of sleep and biopsychosocial profiles with associated neural signatures

Sleep is essential for optimal functioning and health. Interconnected to multiple biological, psychological and socio-environmental factors (i.e., biopsychosocial factors), the multidimensional nature of sleep is rarely capitalized on in research. Here, we deployed a data-driven approach to identify sleep-biopsychosocial profiles that linked self-reported sleep patterns to inter-individual variability in health, cognition, and lifestyle factors in 770 healthy young adults. We uncovered five profiles, including two profiles reflecting general psychopathology associated with either reports of general poor sleep or an absence of sleep complaints (i.e., sleep resilience) respectively. The three other profiles were driven by sedative-hypnotics-use and social satisfaction, sleep duration and cognitive performance, and sleep disturbance linked to cognition and mental health. Furthermore, identified sleep-biopsychosocial profiles displayed unique patterns of brain network organization. In particular, somatomotor network connectivity alterations were involved in the relationships between sleep and biopsychosocial factors. These profiles can potentially untangle the interplay between individuals' variability in sleep, health, cognition and lifestyle - equipping research and clinical settings to better support individual's well-being.

Objective evaluation of excessive daytime sleepiness

Excessive daytime sleepiness (EDS) is multifactorial. It combines, among other things, an excessive propensity to fall asleep ("physiological sleepiness") and a continuous non-imperative sleepiness (or drowsiness/hypo-arousal) leading to difficulties remaining awake and maintaining sustained attention and vigilance over the long term ("manifest sleepiness"). There is no stand-alone biological measure of EDS. EDS measures can either capture the severity of physiological sleepiness, which corresponds to the propensity to fall asleep, or the severity of manifest sleepiness, which corresponds to behavioral consequences of sleepiness and reduced vigilance. Neuropsychological tests (The psychomotor vigilance task (PVT), Oxford Sleep Resistance Test (OSLeR), Sustained Attention to Response Task (SART)) explore manifest sleepiness through several sustained attention tests but the lack of normative values and standardized protocols make the results difficult to interpret and use in clinical practice. Neurophysiological tests explore the two main aspects of EDS, i.e. the propensity to fall asleep (Multiple sleep latency test, MSLT) and the capacity to remain awake (Maintenance of wakefulness test, MWT). The MSLT and the MWT are widely used in clinical practice. The MSLT is recognized as the "gold standard" test for measuring the severity of the propensity to fall asleep and it is a diagnostic criterion for narcolepsy. The MWT measures the ability to stay awake. The MWT is not a diagnostic test as it is recommended only to evaluate the evolution of EDS and efficacy of EDS treatment. Even if some efforts to standardize the protocols for administration of these tests have been ongoing, MSLT and MWT have numerous limitations: age effect, floor or ceiling effects, binding protocol, no normal or cutoff value (or determined in small samples), and no or low test-retest values in some pathologies. Moreover, the recommended electrophysiological set-up and the determination of sleep onset using the 30‑sec epochs scoring rule show some limitations. New, more precise neurophysiological techniques should aim to detect very brief periods of physiological sleepiness and, in the future, the brain local phenomenon of sleepiness likely to underpin drowsiness, which could be called "physiological drowsiness".

Association Between EEG Microarousal During Nocturnal Sleep and Next-Day Selective Attention in Mild Sleep-Restricted Healthy Undergraduates

Purpose

To explore whether sleep electroencephalogram (EEG) microarousals of different standard durations predict daytime mood and attention performance in healthy individuals after mild sleep restriction.

Participants and Methods

Sixteen (nine female) healthy college students were recruited to examine the correlations between nocturnal EEG microarousals of different standard durations (≥3 s, ≥5 s, ≥7 s, ≥9 s) under mild sleep restriction (1.5 h) and the following morning's subjective alertness, mood, sustained attention, and selective attention task performance.

Results

Results revealed that mild sleep restriction significantly reduced subjective alertness and positive mood, while having no significant effect on negative mood, sustained attention and selective attention performance. The number of microarousals (≥5 s) was negatively associated with positive mood at 6:30. The number of microarousals was significantly and positively correlated with the response time difference value of disengagement component of the selective attention task at around 7:30 (≥5 s and ≥7 s) and 9:00 (≥5 s). The number of microarousals (≥7 s) was significantly and positively correlated with the inaccuracy difference value of orientation component of the selective attention task at around 9:00.

Conclusion

The number of EEG microarousals during sleep in healthy adults with mild sleep restriction was significantly and negatively related to their daytime positive affect while positively associated with the deterioration of disengagement and orientation of selective attention performance, but this link is dependent on the standard duration of microarousals, test time and the type of task.

Dynamic associations between glucose and ecological momentary cognition in Type 1 Diabetes

Type 1 diabetes (T1D) is a chronic condition characterized by glucose fluctuations. Laboratory studies suggest that cognition is reduced when glucose is very low (hypoglycemia) and very high (hyperglycemia). Until recently, technological limitations prevented researchers from understanding how naturally-occurring glucose fluctuations impact cognitive fluctuations. This study leveraged advances in continuous glucose monitoring (CGM) and cognitive ecological momentary assessment (EMA) to characterize dynamic, within-person associations between glucose and cognition in naturalistic environments. Using CGM and EMA, we obtained intensive longitudinal measurements of glucose and cognition (processing speed, sustained attention) in 200 adults with T1D. First, we used hierarchical Bayesian modeling to estimate dynamic, within-person associations between glucose and cognition. Consistent with laboratory studies, we hypothesized that cognitive performance would be reduced at low and high glucose, reflecting cognitive vulnerability to glucose fluctuations. Second, we used data-driven lasso regression to identify clinical characteristics that predicted individual differences in cognitive vulnerability to glucose fluctuations. Large glucose fluctuations were associated with slower and less accurate processing speed, although slight glucose elevations (relative to person-level means) were associated with faster processing speed. Glucose fluctuations were not related to sustained attention. Seven clinical characteristics predicted individual differences in cognitive vulnerability to glucose fluctuations: age, time in hypoglycemia, lifetime severe hypoglycemic events, microvascular complications, glucose variability, fatigue, and neck circumference. Results establish the impact of glucose on processing speed in naturalistic environments, suggest that minimizing glucose fluctuations is important for optimizing processing speed, and identify several clinical characteristics that may exacerbate cognitive vulnerability to glucose fluctuations.

Changes in electroencephalography microstates are associated with reduced levels of vigilance after sleep deprivation

Total sleep deprivation (TSD) negatively affects cognitive functions, especially vigilance attention, but studies on vigilance changes in terms of electroencephalography (EEG) microstates after TSD are limited. This study investigates the impact of TSD on vigilance attention, EEG microstates and its relationship. Thirty healthy adult males completed a psychomotor vigilance task (PVT) before, 24 h after, and 36 h after TSD while their EEG was recorded during rest. Microstate analysis revealed significant changes in the occurrence and contribution of microstate class B after TSD. Moreover, changes in the probability of transitioning between microstate classes A and D were observed, correlating with decreased vigilance. Specifically, a positive correlation was found between transitioning from class B to class C and vigilance, while a trend of negative correlation was observed between transitioning between classes A and D and vigilance. These findings indicate abnormal activity in the salience network and dorsal attention network following sleep deprivation. TSD impairs vigilance attention, as demonstrated by the effects on EEG microstate class B and the transitions between classes A and D. The study suggests its potential as an early warning indicator for predicting vigilance attention after sleep deprivation.

Identifying predictors of patient safety competency based on sleep quality in student faculty of nursing and midwifery during the internship period: a multidisciplinary study

BACKGROUND

Ensuring patient safety is of paramount importance in healthcare services. Sleep disorders not only have detrimental effects on the health of healthcare students but also significantly impair their performance, leading to an increased risk of medication errors. These errors can pose a grave threat to the safety and well-being of patients. It is crucial to address and mitigate sleep disorders among internship healthcare students to safeguard the quality of care and minimize potential patient harm.

OBJECTIVES

This study aimed to investigate the predictors of Patient Safety Competency (PSC) based on the sleep quality of internship healthcare students.

METHODS

A study was conducted on 331 students from the Ardabil School of Nursing and Midwifery at Ardabil University of Medical Sciences in northwest Iran from August to December 2022. The participants were selected by stratified random sampling. Data were collected using a demographic information form, the Pittsburgh Sleep Quality Index (PSQI), and the Health Professional Education in Patient Safety Survey (H-PEPSS). The collected data were analyzed using SPSS software version 22.0. Person correlation coefficients were used to examine the relationship between PSC level, its dimensions, and sleep quality, while multiple linear regression was conducted to identify the predictors of PSC.

RESULTS

The competency of nurses in patient safety was average in both classroom and clinical settings. However, their ability to work as a team with other healthcare professionals scored the lowest. In addition, the quality of sleep was found to be a predictor of patient safety competency among healthcare students during their internships.

CONCLUSIONS

It is important to note that healthcare students tend to have moderate patient safety competence (PSC), which is positively correlated with their sleep quality. Therefore, it is vital to identify the key factors that directly affect PSC. This would enable nursing and midwifery faculty administrators to take preventive measures to enhance patient safety competence in both classroom and clinical settings. Additionally, organizing educational workshops that engage students and improve their sleep quality could improve patient care. Practical courses are recommended for health professionals and students in clinical settings to enhance patient safety competencies. Additionally, student internships should receive hands-on training to improve teamwork and rest conditions.

Cognitive impairment after sleep deprivation: The role of precuneus related connectivity on the intra-individual variability changes

OBJECTIVE

Intra-individual variability (IIV) in cognitive performance is thought to reflect the efficiency with which attentional resources are allocated in different circumstances requiring cognitive control. IIV in cognitive performance is associated with the strength of the negative correlation between task-positive network and default mode network (DMN) activity. In this study, we investigated the impact of sleep deprivation (SD) on functional connectivity (FC) between the DMN and psychomotor vigilance task-related network (PVT-RN), and its relationship with IIV in cognitive performance.

METHODS

Two analyses, network-level independent component analysis (NL-ICA) and region-level (RL)-ICA, were employed to compare the coefficient of variation (CV) of the PVT between normal sleep and SD conditions across 67 healthy participants.

RESULTS

After SD, in NL-ICA, the FC between the PVT-RN and DMN was positively correlated with the CV of the PVT, as well as the changes therein, compared with normal sleep. Using a mask derived from the DMN and PVT-RN, the RL-ICA revealed that 12 edges/connections between DMN and PVT independent components were associated with the CV of the PVT, with nine of these connections involving the precuneus.

CONCLUSIONS

These findings suggest that the precuneus may play a crucial role in the interactions of various brain functions during the PVT, with the connections between the precuneus and frontoparietal and somatosensory networks being significantly altered after SD. Moreover, following SD, weakened negative FC between the precuneus and bilateral inferior parietal lobule may disrupt the balance between cognitive and executive control functions, leading to a decline in cognitive performance.

Shift work is associated with extensively disordered sleep, especially when working nights

Background

Shift work is generally associated with working and sleeping out of phase with the endogenous, circadian sleep-wake cycle. This exerts detrimental effects on sleep health. The present study aimed at evaluating the presence of short and long sleep as well as sleep disorders within a broad range of shift work schedules and elucidating the role of sociodemographic factors therein.

Methods

A large dataset containing information on sleep was collected through advertisement in a Belgium newspaper (De Standaard). Adult, working individuals were selected (n = 37,662) and categorized based on their work schedule (regular day, early morning, evening, night, and rotating shift). In this cross-sectional study, prevalence rates of short sleep (≤6 h), long sleep (≥9 h) and sleep disorders (screened with Holland Sleep Disorders Questionnaire), and associations between these sleep variables and sociodemographics (age, sex, education, living companion(s)) were analyzed using binominal logistic regression analyses.

Results

In the total sample all sociodemographic factors affected prevalences of short, long and disordered sleep, consistent with previous studies. Compared to day workers, shift workers more frequently reported short sleep, most prominently night workers (26 vs. 50%) (p < 0.001). Furthermore, all sleep disorders as well as sleep disorder comorbidity were more common in shift workers, again most pronounced in night workers (all p < 0.05). In night shift workers the level of education had the strongest associations with disturbed sleep with a two-fold higher prevalence of short and disordered sleep in low relative to academic educated groups (all p < 0.02).

Conclusion

Shift work is related not only to curtailed sleep and shift work disorder, but also to a plethora of sleep disorders, including insomnia, sleep-related breathing disorders and sleep-related movement disorders. Our findings imply that education on coping strategies may be especially important for young and/or lower educated shift workers.

Biomarkers linking habitual short sleep duration with risk of cardiometabolic disease: current progress and future directions

Approximately one in three adults in the United States sleeps less than the recommended 7 h per night. Decades of epidemiological data and data from experimental sleep restriction studies demonstrate short sleep duration is associated with adverse cardiometabolic risk, including risk of type 2 diabetes and cardiovascular disease. However, the precise mechanisms underlying this risk are not fully elucidated and there is a lack of sleep-based interventions designed to mitigate such risk. One strategy to overcome these limitations is to develop biomarkers that link habitual short sleep duration with adverse cardiometabolic risk. Such biomarkers could inform biochemical mechanisms, identify new targets for interventions, support precision medicine by identifying individuals most likely to benefit from sleep-based interventions, and ultimately lead to improved cardiometabolic health in people with habitual short sleep durations. Early progress demonstrates proof-of-principle that omics-based technologies are a viable approach to create biochemical signatures (biomarkers) of short sleep duration, primarily derived from acute studies of experimental sleep restriction. Yet, much work remains. Notably, studies that translate early findings from experimental sleep restriction to free-living adults with habitual short sleep duration have high potential to advance the field. Such studies also create an exciting opportunity for larger randomized controlled trials that simultaneously identify biomarkers of habitual short sleep duration and evaluate the efficacy of sleep-based interventions. Ultimately, early progress in developing molecular biomarkers of short sleep duration combined with the prior decades of progress in the sleep and metabolism fields provide the foundation for exciting progress in the biomarker development space.

Time-of-day effects on speed and accuracy performance during simulated shiftwork

Performance on tasks involving speed and accuracy fluctuate throughout the 24-h day negatively affecting shift workers and organizations. Two simulated work shifts common in occupational settings were used to assess performance on a vigilance and math task. In study 1, 33 sleep-deprived participants completed a nightshift. In study 2, 32 partially sleep-deprived participants completed a dayshift. These studies found that performance differed between the type of task and the type of simulated shift where performance during the nightshift was worse than during the dayshift. In addition, collapsing speed and accuracy on the math task into inverse efficiency scores provided a unique measure that captured the impact of circadian rhythms during shiftwork. The current study also indicated that participants adopted cognitive strategies including speed-accuracy tradeoff and regulatory foci regarding work motivation (prevention focus and promotion focus) when completing the tasks depending on time-of-day, type of shift, circadian rhythms, and amount of sleep deprivation. This suggests that researchers and organizations should consider cognitive strategies in addition to the physiological components of sleep deprivation and circadian rhythms when investigating and documenting the impact of time-of-day due to different types of shiftwork conditions on performance and safety.

The sleep, circadian, and cognitive performance consequences of watchkeeping schedules in submariners: A scoping review

Watchkeeping schedules are essential for maintaining submarine operations, but come with human risk factors including, disrupted sleep, circadian misalignment, and cognitive deficits. There is now an emerging literature examining the strengths and weaknesses of submarine watchkeeping schedules trialled in the field and under simulated laboratory conditions. The aim of this scoping review was to summarise this literature. A systematic search of peer-reviewed journal articles and industry reports listed in MEDLINE, PsychINFO, PubMed, Scopus, Embase and Google Scholar undertaken in May 2023 returned 7298 papers. Following screening procedures, 13 studies were identified for inclusion. The findings revealed that sleep was sufficiently preserved regardless of watchkeeping schedule (total sleep time = 5.46-7.89 h), circadian misalignment was greater for non-24 h schedules, and longer off-watch periods were associated with better cognitive performance. Taken together, when comparing between watchkeeping schedules, the present findings suggest that the 4 h-on/8 h-off and 8 h-on/16 h-off schedules may be a good compromise when balancing human risk factors and operational demands. However, submarines are complex and challenging environments to study and there is a need to expand the literature. More research comparing watchkeeping schedules is needed. Future studies should focus on cognitive performance measures, such as problem-solving, prioritisation and executive decision-making to address present shortcomings, and an examination of sleep and circadian countermeasures to assist with adaptation either initiated pre-deployment or by modifying the submarine environment itself should be considered.

What is sleep exactly? Global and local modulations of sleep oscillations all around the clock

Wakefulness, non-rapid eye-movement (NREM) and rapid eye-movement (REM) sleep differ from each other along three dimensions: behavioral, phenomenological, physiological. Although these dimensions often fluctuate in step, they can also dissociate. The current paradigm that views sleep as made of global NREM and REM states fail to account for these dissociations. This conundrum can be dissolved by stressing the existence and significance of the local regulation of sleep. We will review the evidence in animals and humans, healthy and pathological brains, showing different forms of local sleep and the consequences on behavior, cognition, and subjective experience. Altogether, we argue that the notion of local sleep provides a unified account for a host of phenomena: dreaming in REM and NREM sleep, NREM and REM parasomnias, intrasleep responsiveness, inattention and mind wandering in wakefulness. Yet, the physiological origins of local sleep or its putative functions remain unclear. Exploring further local sleep could provide a unique and novel perspective on how and why we sleep.

Causal relationship between sleep traits and cognitive impairment: A Mendelian randomization study

OBJECTIVE

Observational studies had demonstrated a link between sleep disturbances and cognitive decline. Here, we aimed to investigate the causal association between genetically predicted sleep traits and cognitive impairment using Mendelian randomization (MR).

METHODS

Using strict criteria, we selected genetic variants from European ancestry Genome-wide association studies (GWAS) from the Sleep Disorders Knowledge Portal and UK Biobank as instrumental variables for several sleep traits, including insomnia, sleep duration, daytime sleepiness, daytime napping, and chronotype. Summary statistics related to cognitive impairment were derived from five different GWAS, including the Social Science Genetic Association Consortium. The role of self-reported sleep trait phenotypes in the etiology of cognitive impairment was explored using inverse-variance weighted (IVW) tests, MR-Egger tests, and weighted medians, and sensitivity analyses were conducted to ensure robustness.

RESULTS

In the main IVW analysis, sleep duration (reaction time: β = -0.05, 95% CI -0.07 to -0.04, p = 1.93×10-12 ), daytime sleepiness (average cortical thickness: β = -0.12, 95% CI -0.22 to -0.02, p = 0.023), and daytime napping (fluid intelligence: β = -0.47, 95% CI -0.87 to -0.07, p = 0.021; hippocampal volume in Alzheimer's disease: β = -0.99, 95% CI -1.64 to -0.35, p = 0.002) were significantly negatively correlated with cognitive performance. However, any effects of insomnia and chronotype on cognitive impairment were not determined.

CONCLUSIONS

Our findings highlighted that focusing on sleep behaviors or distinct sleep patterns-particularly sleep duration, daytime sleepiness, and daytime napping, was a promising approach for preventing cognitive impairment. This study also shed light on risk factors for and potential early markers of cognitive impairment risk factors.