Frontal lobe function, sleep loss and fragmented sleep

Sleep Time and Depression Symptoms as Predictors of Cognitive Development Among Adolescents: A Cross-Lagged Study From China

Sleep time and depression symptoms are important factors affecting cognitive development in adolescents. Based on the China Education Panel Survey (CEPS) database, this study used a two-wave cross-lagged model to examine the bidirectional relationship between sleep time, depression symptoms, and cognitive development. Descriptive statistics showed that Chinese adolescents' cognitive development increased significantly from 7th to 8th grade in junior high school, but unfortunately, their depression level and average sleep time per night demonstrated a slightly deteriorating trend. Correlation analysis showed that there was a relatively stable negative correlation between cognitive development, sleep time, and depression symptoms. Moreover, the cross-lagged model revealed that there was a bidirectional relationship between cognitive development and sleep time, a bidirectional relationship between depression symptoms and sleep time, and a unidirectional relationship between depression symptoms and cognitive development. Male adolescents in the subgroup were consistent with the total sample. Among female adolescents, only cognitive development and sleep time have a bidirectional relationship, while depression symptoms and cognitive development, and depression symptoms and sleep time have a unidirectional relationship. Therefore, it is of significance to take targeted action to promote cognitive development and healthy growth in adolescents worldwide.

Decoupling of global signal and cerebrospinal fluid inflow is associated with cognitive decline in patients with obstructive sleep apnoea

OBJECTIVES

The role of cortical glymphatic dysfunction in the cognitive impairment of the obstructive sleep apnea (OSA) requires further study. To compare the coupling between the resting-state blood-oxygen-level-dependent (BOLD) signals and cerebrospinal fluid (CSF) signals (BOLD-CSF coupling), a proxy for the cortical glymphatic function, across patients with differing severities of OSA and relate them with disease characteristics and treatment.

METHODS

A total of 153 participants (89 OSA patients and 64 matched controls) were prospectively included. OSA patients were classified into three groups (mild, moderate, and severe OSA) according to the apnea-hypopnea index (AHI). All participants underwent neuropsychological assessment and BOLD functional magnetic resonance imaging. BOLD-CSF coupling was assessed at global and regional levels and correlated with the cognitive impairment. Alterations in BOLD-CSF coupling and cognitive performance after treatment were assessed in OSA patients.

RESULT

Severe OSA patients exhibited weaker global and anterior BOLD-CSF coupling than mild OSA patients, moderate OSA patients, and healthy controls (HCs). Furthermore, the weaker global and anterior BOLD-CSF coupling was associated with poor cognitive performance in all OSA patients. Notably, cognitive performance and cortical glymphatic function improved significantly in patients with OSA after treatment.

CONCLUSION

Our findings demonstrated cortical glymphatic dysfunction in severe OSA patients, especially in the anterior region of the brain. Cortical glymphatic dysfunction may underlie the cognitive impairment in OSA patients, both of which would improve in OSA patients after treatment.

Sleep Alterations and Cognitive Decline

Sleep disturbances and cognitive decline are intricately connected, and both are prevalent in aging populations and individuals with neurodegenerative disorders such as Alzheimer's disease (AD) and other dementias. Sleep is vital for cognitive functions including memory consolidation, executive function, and attention. Disruption in these processes is associated with cognitive decline, although causal evidence is mixed. This review delves into the bidirectional relationship between alterations in sleep and cognitive impairment, exploring key mechanisms such as amyloid-β accumulation, tau pathology, synaptic homeostasis, neurotransmitter dysregulation, oxidative stress, and vascular contributions. Evidence from both experimental research and population-based studies underscores the necessity of early interventions targeting sleep to mitigate risks of neurodegenerative diseases. A deeper understanding of the interplay between sleep and cognitive health may pave the way for innovative strategies to prevent or reduce cognitive decline through improved sleep management.

Neural indicators of sleep loss and sleep propensity in male military trainees: Insights from dry-electrode EEG-An exploratory study

This study examined the impact of reduced sleep on electroencephalogram (EEG) activity during cognitive tasks in Military Clearance Diver trainees using a novel dry-electrode EEG system. Seven male participants underwent two 5-day periods: a baseline and a "live-in" phase with increased workload and reduced sleep (5.4 ± 0.1 vs. 7.4 ± 0.7 h). EEG was recorded daily in the early morning (am) and late afternoon (pm) during a Psychomotor Vigilance Test (PVT), two oculography tests (am: n = 4; pm: n = 3), and 2 min of eyes-closed rest. Significant increases in theta (t (29) = 2.308, p = 0.028, d = 0.421) and alpha (t (29) = 2.124, p = 0.042, d = 0.388) power spectrum densities were observed in the "live-in" phase during the PVT. These findings align with increased lower frequency activity over time awake, reflecting heightened sleep propensity. Sleep loss was further confirmed by declining Odds Ratio Product (ORP) values. This study demonstrates the feasibility of dry-electrode EEG in detecting fatigue-related neural changes and highlights the potential of ORP as a quantifiable fatigue marker. These insights may inform operational settings, such as military diver performance monitoring and fatigue management strategies.

Carer-reported sleep disturbance and carer- and teacher-rated executive functioning in children with prenatal alcohol exposure and Fetal Alcohol Spectrum Disorder

Children with prenatal alcohol exposure (PAE) and Fetal Alcohol Spectrum Disorder (FASD) have high rates of sleep disturbance and marked difficulties with executive functioning (EF). Sleep disturbance has been associated with poorer EF across development in typically developing children. The contribution of insomnia symptoms and nightmares to EF difficulties in children with PAE and FASD is unclear. The current study examined whether caregiver-reported insomnia symptoms and nightmares predicted difficulties with EF in children with PAE who were assessed at FASD diagnostic clinics. Archival data on 116 children with PAE assessed at FASD diagnostic clinics were extracted from databases. Children were assigned to a preschool-age group (3.1 to 5.9 years, n = 40) and a school-age group (5.9 to 10.9 years, n = 76). Insomnia symptoms and nightmares were measured using items extracted from the Child Behavior Checklist (CBCL) while EF was measured using the caregiver and teacher Behavior Rating Inventory of Executive Function (BRIEF) rating forms. Bootstrapped regression models were used examine the effects of insomnia symptoms and nightmares on domains of EF in each group while adjusting for potential confounds. For preschool children, insomnia symptoms were associated with greater daytime tiredness while nightmares were associated with greater difficulties with Emergent Metacognition according to their teachers. For school-age children, insomnia symptoms predicted greater EF difficulties across most domains according to their caregivers but not teachers. Sleep disturbance may compound EF impairments in children with PAE and should be screened for as part of FASD diagnostic assessment.

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.

The relationship between sleep quality and gait in people with multiple sclerosis: A pilot study

Background

Gait deficits are common among people with multiple sclerosis (PwMS). Therefore, investigating factors that may influence walking in PwMS is important. Previous studies in older adults and other neurological populations demonstrated the relationship between sleep quality and gait performance. Despite the fact that the prevalence of poor sleep quality is very high among PwMS, little is known about the effect of sleep quality on gait among PwMS.

Objective

This study aimed to explore the relationship between sleep quality and gait performance in PwMS.

Methods

Forty-one PwMS participated in the study between February 2019 and December 2019. Participants were asked to walk at a self-selected speed over 10 m with an inertial measurement unit (IMU) attached over the back. Walking speed, step length (left and right), and step time were calculated. Sleep was estimated objectively using a wrist-worn triaxle-accelerometer; the derived parameters were sleep efficiency (SE) and the number of awakening after sleep onset (NASO).

Results

SE significantly correlated with step length (p = 0 . 02 ). Furthermore, the NASO significantly correlated with gait speed (p = 0 . 03 ), and step-time (p = 0 . 02 ). These correlations remained significant even after adjusting for age and disease duration.

Conclusion

We observed that when corrected for disease duration and age there were relationships between NASO and SE to gait parameters; these observations warrant further investigations.

Upper Airway-Related Symptoms According to Mental Illness and Sleep Disorders among Workers Employed by a Large Non-Profit Organization in the Mountain West Region of the United States

The relationships between selected upper airway-related symptoms (speech disturbances, voice disorders, cough, and breathing abnormalities) and mental illness and sleep disorders have been previously demonstrated. However, these relationships have not been compared in a single study with consideration of potential confounding variables. The current research incorporates a descriptive study design of medical claims data for employees (~21,362 per year 2017-2021) with corporate insurance to evaluate the strength of these relationships, adjusting for demographic variables and other important confounders. The upper airway-related symptoms are each significantly and positively associated with several mental illnesses and sleep disorders, after adjusting for demographic and other potential confounders. The rate of any mental illness is 138% (95% CI 93-195%) higher for speech disturbances, 55% (95% CI 28-88%) higher for voice disorders, 28% (95% CI 22-34%) higher for cough, and 58% (95% CI 50-66%) higher for breathing abnormalities, after adjustment for the confounding variables. Confounding had significant effects on the rate ratios involving cough and breathing abnormalities. The rate of any sleep disorder is 78% (95% CI 34-136%) higher for speech disturbances, 52% (95% CI 21-89%) higher for voice disorders, 34% (95% CI 27-41%) higher for cough, and 172% (95% CI 161-184%) higher for breathing abnormalities, after adjustment for the confounding variables. Confounding had significant effects on each of the upper airway-related symptoms. Rates of mental illness and sleep disorders are positively associated with the number of claims filed for each of the upper airway-related symptoms. The comorbid nature of these conditions should guide clinicians in providing more effective treatment plans that ultimately yield the best outcome for patients.

Boarding versus day-students: A mixed-methods analysis of sleep and its relationship with psychological distress

BACKGROUND

Boarding students face unique challenges when entering school, including: adapting to a novel environment, where they are separated from family, friends and culture, for up to 40 weeks per year. A particular challenge is sleep. A further challenge is coping with the demands of boarding with its potential impact on psychological well-being.

AIMS

To explore how boarders' sleep differs from that of their day-student peers, and how this relates to psychological well-being.

SAMPLE AND METHODS

309 students (59 boarding students and 250 day-students, at one Adelaide school) completed the School Sleep Habits Survey, Depression-Anxiety-Stress-Scale-21 (DASS-21), and Flourishing Scale. Boarding students additionally completed the Utrecht Homesickness Scale. Thirteen boarding students described experiences of sleeping in boarding through focus groups.

RESULTS

Boarding students, compared to day-students reported 40 minutes more sleep per weeknight (p < .001), with earlier sleep onset (p = .026), and later wake-up (p = .008) times. No significant differences were observed between boarding' and day-students' DASS-21 scores. Hierarchical regression revealed longer total weekday sleep time predicted higher psychological well-being in both boarding and day-students. Additionally, in boarding students, low homesickness-loneliness and homesickness-ruminations further predicted psychological well-being. Thematic analysis of boarding students' focus group responses revealed that night-time routine, and restricting technology use at night facilitated sleep.

CONCLUSIONS

This study supports - in both boarding and day-students - the importance of sleep for adolescent well-being. Sleep hygiene can play an important role in boarding student sleep, especially: regular night-time routine and restricting technology use at night. Finally, these findings suggest that poor sleep and homesickness have an adverse effect on boarding student psychological well-being. This study highlights the importance of strategies which promote sleep hygiene and minimize homesickness, in boarding school students.

Association between sleep change patterns and mental health among preschoolers: The mediating role of resilience

Sleep disturbance has been recognized as an important factor influencing mental health problems in preschool children. However, no longitudinal studies have investigated the association between sleep change patterns and mental health in preschoolers or the mediating role of resilience. Here, data were collected from 1595 preschool children in 26 kindergartens in four counties in Anhui Province, China, who were followed up (T2) 1 year apart based on baseline surveys (T1). The primary caregivers of the children were asked to complete a structured questionnaire through face-to-face interviews or by completing it themselves. Pearson's correlation and linear regression were used to analyze the relationships among sleep patterns, mental health, and resilience in preschoolers. A structural equation model was used for the mediation analysis. Four patterns of sleep change were identified: persistent-low pattern (1.7%), decreasing pattern (9.8%), increasing pattern (7.3%), and persistent-high pattern (81.3%). Compared to the persistent-low pattern, the increasing pattern and persistent-high pattern were associated with emotional behavioral problems (EBPs) and anxiety. Resilience played a fully mediating role in the relationship between increasing pattern, persistent-high pattern, and EBPs. Resilience partially mediated the effects of increasing and persistent-high pattern on anxiety. More attention should be paid to sleep problems in children with increasing and persistent-high sleep patterns. Resilience is important for understanding the mechanism underlying the correlation between sleep patterns, EBPs, and anxiety. Considering the EBPs and anxiety of preschool children, early intervention for resilience should be considered.

The Influence of Emotional Regulation and Cognitive Flexibility on Sleep Habits in Spanish Children and Adolescents through the Lens of Parents

BACKGROUND

Previous research studies have suggested the importance of studying the relationship between emotional regulation and sleep habits. Some investigations have especially focused on how emotional regulation could impact sleep habits in children and adolescents. Therefore, these researchers have stated there exists a two-way direction in this relationship.

OBJECTIVE

This study aimed to analyze the influence of emotional regulation on sleep habits in Spanish children and adolescents and the mediating role of anxiety in this relationship.

METHOD

Participants were 953 Spanish parents who completed the assessment protocol according to their children and adolescents' information.

RESULTS

The results revealed moderate-strong correlations between emotional regulation problems and sleep habit disturbances (r = 0.375, p < 0.001), trait (r = 0.488, p < 0.001) anxiety, and state (r = 0.589, p < 0.001) anxiety. Additionally, emotional regulation showed a direct impact on sleep habits (β = 0.011, p = 0.005). Trait and state anxiety demonstrated a significant mediating role in the relationship between emotional regulation and sleep habits.

CONCLUSIONS

Emotional regulation may have an impact on sleep habits during childhood and adolescence, suggesting the importance of early intervention focused on the emotions management and the prevention of sleep habit disturbances.

The Relationship Between Sleep and Brain Function in Older Adults With Chronic Kidney Disease and Self-Identified Cognitive Impairment

Older adults with chronic kidney disease (CKD) are at risk for cognitive impairment and sleep disturbances. The purpose of the current study was to investigate the relationship between sleep and brain structure/function in older adults with CKD and self-identified cognitive impairment. The sample (N = 37) had a mean age of 68 years (SD = 4.9 years), estimated glomerular filtration rate of 43.7 mL/min/1.73m2 (SD = 10.98), median sleep time of 7.4 hours, and was 70% female. Sleeping <7.4 hours, compared to ≥7.4 hours, was associated with better attention/information processing (β = 11.46, 95% confidence interval [CI] [3.85, 19.06]) and better learning/memory (β = 2.06, 95% CI [0.37, 3.75]). Better sleep efficiency was associated with better global cerebral blood flow (β = 3.30, 95% CI [0.65, 5.95]). Longer awake length after sleep onset was associated with worse fractional anisotropy of the cingulum (β = -0.01, 95% CI [-0.02, -0.003]). Sleep duration and continuity may be related to brain function in older adults with CKD and self-identified cognitive impairment. [Journal of Gerontological Nursing, 49(7), 31-39.].

Effects of a single night of continuous positive airway pressure on spontaneous brain activity in severe obstructive sleep apnea

This study aimed to investigate the effect of a single night of continuous positive airway pressure (CPAP) treatment on spontaneous brain activity and the underlying neuropathological mechanisms in patients with severe obstructive sleep apnea (OSA). The study involved 30 severe OSA patients and 19 healthy controls (HC). Fractional amplitude of low-frequency fluctuation (fALFF) and regional homogeneity (ReHo) methods were employed to evaluate spontaneous brain activity in all participants. Following a single night of CPAP treatment, ReHo values increased in the bilateral caudate and decreased in the right superior frontal gyrus. The fALFF values increased in the left orbital part of the middle frontal gyrus and the right orbital of the inferior frontal gyrus (Frontal_Inf_Orb_R). However, fALFF values decreased in the medial part of the left superior frontal gyrus and the right supramarginal part of the inferior parietal lobe. Pearson correlation analysis revealed a positive relationship between the change in the fALFF in the Frontal_Inf_Orb_R and the change in REM sleep duration (r = 0.437, p = 0.016) following a single night of CPAP treatment. We concluded that observing changes in abnormal fALFF and ReHo in OSA patients before and after a single night of CPAP treatment may enhance our understanding of the neurological mechanisms in patients with severe OSA.

Changes in Functional Connectivity of Hippocampal Subregions in Patients with Obstructive Sleep Apnea after Six Months of Continuous Positive Airway Pressure Treatment

Previous studies have shown that the structural and functional impairments of hippocampal subregions in patients with obstructive sleep apnea (OSA) are related to cognitive impairment. Continuous positive airway pressure (CPAP) treatment can improve the clinical symptoms of OSA. Therefore, this study aimed to investigate functional connectivity (FC) changes in hippocampal subregions of patients with OSA after six months of CPAP treatment (post-CPAP) and its relationship with neurocognitive function. We collected and analyzed baseline (pre-CPAP) and post-CPAP data from 20 patients with OSA, including sleep monitoring, clinical evaluation, and resting-state functional magnetic resonance imaging. The results showed that compared with pre-CPAP OSA patients, the FC between the right anterior hippocampal gyrus and multiple brain regions, and between the left anterior hippocampal gyrus and posterior central gyrus were reduced in post-CPAP OSA patients. By contrast, the FC between the left middle hippocampus and the left precentral gyrus was increased. The changes in FC in these brain regions were closely related to cognitive dysfunction. Therefore, our findings suggest that CPAP treatment can effectively change the FC patterns of hippocampal subregions in patients with OSA, facilitating a better understanding of the neural mechanisms of cognitive function improvement, and emphasizing the importance of early diagnosis and timely treatment of OSA.

Time Use and Cognitive Achievement among Adolescents in China: Depression Symptoms as Mediators

Everyone's time is limited, and there is competition between different aspects of time use; this requires comprehensive consideration of the effects of different aspects of time use on cognitive achievement in adolescents. This study uses a dataset of 11,717 students from a nationally representative large-scale survey project conducted in 2013 to 2014 to clarify the relationship between time use (including working on homework, playing sports, surfing the Internet, watching TV, and sleeping) and cognitive achievement among Chinese adolescents, and explores the mediating role of depression symptoms in the relationship between time use and cognitive achievement. The results of the correlation analysis show that the average daily time spent on homework, playing sports, and sleeping is significantly positively correlated with cognitive achievement (p < 0.01), while time spent surfing the Internet and watching TV are significantly negatively correlated with cognitive achievement (p < 0.01). The results of the mediating effect model show that depression symptoms play a mediating role in the relationship between time use and cognitive achievement among Chinese adolescents. Specifically, time spent playing sports (indirect effect = 0.008, p < 0.001) and sleeping (indirect effect = 0.015, p < 0.001) have a positive effect on cognitive achievement when using depression symptoms as mediators; time spent on homework (indirect effect = -0.004, p < 0.001), surfing the Internet (indirect effect = -0.002, p = 0.046), and watching TV (indirect effect = -0.005, p < 0.001) have a negative effect on cognitive achievement when using depression symptoms as mediators. This study contributes to the understanding of the relationship between time use and cognitive achievement among Chinese adolescents.

NREM sleep as a novel protective cognitive reserve factor in the face of Alzheimer's disease pathology

BACKGROUND

Alzheimer's disease (AD) pathology impairs cognitive function. Yet some individuals with high amounts of AD pathology suffer marked memory impairment, while others with the same degree of pathology burden show little impairment. Why is this? One proposed explanation is cognitive reserve i.e., factors that confer resilience against, or compensation for the effects of AD pathology. Deep NREM slow wave sleep (SWS) is recognized to enhance functions of learning and memory in healthy older adults. However, that the quality of NREM SWS (NREM slow wave activity, SWA) represents a novel cognitive reserve factor in older adults with AD pathology, thereby providing compensation against memory dysfunction otherwise caused by high AD pathology burden, remains unknown.

METHODS

Here, we tested this hypothesis in cognitively normal older adults (N = 62) by combining 11C-PiB (Pittsburgh compound B) positron emission tomography (PET) scanning for the quantification of β-amyloid (Aβ) with sleep electroencephalography (EEG) recordings to quantify NREM SWA and a hippocampal-dependent face-name learning task.

RESULTS

We demonstrated that NREM SWA significantly moderates the effect of Aβ status on memory function. Specifically, NREM SWA selectively supported superior memory function in individuals suffering high Aβ burden, i.e., those most in need of cognitive reserve (B = 2.694, p = 0.019). In contrast, those without significant Aβ pathological burden, and thus without the same  need for cognitive reserve, did not similarly benefit from the presence of NREM SWA (B = -0.115, p = 0.876). This interaction between NREM SWA and Aβ status predicting memory function was significant after correcting for age, sex, Body Mass Index, gray matter atrophy, and previously identified cognitive reserve factors, such as education and physical activity (p = 0.042).

CONCLUSIONS

These findings indicate that NREM SWA is a novel cognitive reserve factor providing resilience against the memory impairment otherwise caused by high AD pathology burden. Furthermore, this cognitive reserve function of NREM SWA remained significant when accounting both for covariates, and factors previously linked to resilience, suggesting that sleep might be an independent cognitive reserve resource. Beyond such mechanistic insights are potential therapeutic implications. Unlike many other cognitive reserve factors (e.g., years of education, prior job complexity), sleep is a modifiable factor. As such, it represents an intervention possibility that may aid the preservation of cognitive function in the face of AD pathology, both present moment and longitudinally.

Sleep, Circadian Rhythms, and Cognitive Dysfunction in Huntington's Disease

BACKGROUND

In healthy people, sleep and circadian disruption are linked to cognitive deficits. People with Huntington's disease (HD), who have compromised brain function and sleep and circadian disturbances, may be even more susceptible to these cognitive effects.

OBJECTIVE

To conduct a comprehensive review and synthesis of the literature in HD on the associations of cognitive dysfunction with disturbed sleep and circadian rhythms.

METHODS

We searched MEDLINE via OVID, CINAHL Plus, EMBASE via OVID, and PubMed in May 2023. The first author then screened by title and abstract and conducted a full review of remaining articles.

RESULTS

Eight studies investigating the influence of sleep and/or circadian rhythms on cognitive function in HD were found. In manifest HD, poorer sleep was associated with worse cognitive function. For behavioral 24-hour (circadian) rhythms, two studies indicated that later wake times correlated with poorer cognitive function. No reported studies in HD examined altered physiological 24-hour (circadian) rhythms and cognitive impairment.

CONCLUSION

Some associations exist between poor sleep and cognitive dysfunction in manifest HD, yet whether these associations are present before clinical diagnosis is unknown. Whether circadian disturbances relate to cognitive impairment in HD also remains undetermined. To inform sleep and circadian interventions aimed at improving cognitive symptoms in HD, future research should include a range of disease stages, control for external factors, and utilize robust cognitive batteries targeted to the aspects of cognitive function known to be adversely affected in HD.

[Sleep disorders and fatigue in patients with different forms of myotonic dystrophy type 1]

OBJECTIVE

To characterize sleep disorders in children and adults with different forms of myotonic dystrophy type 1 (DM1), to assess their impact on cognitive functions, excessive daytime sleepiness (EDS) and fatigue, to determine the relationship of EDS, fatigue, and sleep disorders with the quality of life of patients.

MATERIAL AND METHODS

The study included 48 adults and 9 children with confirmed DM1. Patients underwent an assessment of clinical and anamnestic data, neurological, cognitive status, severity of EDS, fatigue, quality of life according to international scales and questionnaires. Polysomnography was performed to identify sleep disorders.

RESULTS

Obstructive sleep apnea syndrome (OSAS) was found in 78% of children and 79.2% of adults. The severity of OSAS in adults, in contrast to children, was influenced by obesity (p<0.001), the severity of muscle weakness (p=0.033), especially the neck muscles (p=0.018). In patients with OSAS and nocturnal hypoxemia, an increase in the duration of the 1st stage of sleep (p=0.008) and in the microactivation index (p=0.005) was revealed. EDS and fatigue were present in 31 (64.6%) and 34 (70.8%) adults, respectively, in 9 (18.8%) they emerged at the onset of the disease. The greater severity of muscle symptoms, anxiety, depression contributed to increased fatigue in adults and the presence of obesity and type 2 diabetes mellitus contributed to EDS. Increased fatigue affects the quality of life to a greater extent than EDS and sleep disturbances.

CONCLUSION

OSAS, the development of which is facilitated by the presence of muscle weakness and obesity, is the leading syndrome among the spectrum of sleep disorders in all age groups. Cognitive and emotional impairments are not the result of sleep apnea, but rather develop because of a primary CNS lesion. The presence of increased fatigue reduced the quality of life of patients.

Prefrontal brain function in patients with chronic insomnia disorder: A pilot functional near-infrared spectroscopy study

Purpose

Insomnia is one of the most common diseases in elderly patients, which seriously affect the quality of life and psychological state of patients. The purpose of this study was to investigate the changes in the functional network pattern of the prefrontal cortex in patients with chronic insomnia disorder (CID) after taking drugs, using non-invasive and low-cost functional neuroimaging with multi-channel near-infrared spectroscopy (fNIRS).

Methods

All subjects were assessed using the Pittsburgh Sleep Quality Index (PSQI), Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), and fNIRS. The fNIRS assessment consists of two parts: the verbal fluency test (VFT) task state and the resting state, which assessed the differences in prefrontal activation and functional connectivity, respectively.

Results

A total of 30 patients with chronic insomnia disorder (CID) and 15 healthy peers completed the study. During the VFT task, a significantly lower PFC activation was observed in patients with insomnia compared to the control group (P < 0.05). However, the PFC activation in patients taking medication was higher than in patients who did not receive medication. Functional connectivity analysis showed a weaker mean PFC channel connectivity strength in patients with CID who did not receive drug treatment. Drug treatment resulted in enhanced functional connectivity of the prefrontal lobe, especially the DLPFC and frontal poles.

Conclusion

A weak prefrontal cortex response was detected in patients with CID when performing the VFT task, which could be enhanced by taking hypnotics. The weakened right prefrontal lobe network may play a role in the development of CID. fNIRS may serve as a potential tool to assess sleep status and guide drug therapy.

Relationships between brain tissue damage, oxygen desaturation, and disease severity in obstructive sleep apnea evaluated by diffusion tensor imaging

STUDY OBJECTIVES

Patients with obstructive sleep apnea (OSA) show brain injury in sites responsible for autonomic, cognitive, and respiratory functions. Brain changes in OSA may vary with disease severity as assessed by the apnea-hypopnea index (AHI), which does not provide information about the apnea depth and length in contrast to oxygen desaturation. Although significant associations with brain injury and AHI are known in OSA, it is unclear whether AHI or the extent of oxygen desaturations better correlate with brain damage. We evaluated associations between brain changes, AHI, and oxygen desaturation using diffusion tensor imaging-based measures.

METHODS

We acquired diffusion tensor imaging data from 19 patients with OSA using a 3.0-Tesla MRI scanner and calculated, normalized, and smoothed mean, axial, and radial diffusivity maps that were used for correlations between brain changes, oxygen desaturation, and AHI values.

RESULTS

Positive correlations with extent of injury (mean, axial, and radial diffusivity values) and AHI appeared in the frontal areas, cingulate and insula, amygdala, hippocampus, and basal pons, and negative associations emerged in the putamen, internal-capsule, globus-pallidus, and cerebellar cortices. Regional diffusivity values and oxygen desaturation showed positive correlations in the cingulate, frontal, putamen, and cerebellar sites, and negative relationships in several areas, including the occipital cortex.

CONCLUSIONS

Patients with OSA show negative and positive correlations, indicated by increased and decreased diffusivity values, resulting from chronic and acute changes in those areas. The extent of injury in OSA partially depends on the extent of AHI and oxygen desaturation, with the effects representing continued development from acute to chronic processes.

CITATION

Sahib A, Roy B, Kang D, Aysola RS, Wen E, Kumar R. Relationships between brain tissue damage, oxygen desaturation, and disease severity in obstructive sleep apnea evaluated by diffusion tensor imaging. J Clin Sleep Med. 2022;18(12):2713-2721.

Sleep quality and creativity in Chinese college student during the COVID-19 pandemic: The mediating role of executive function

Background

COVID-19 has impacted adolescents' interpersonal relationships, life attitudes, and mental health during the past 3 years. However, previous studies predominantly focused on negative problems, while few studies assessed the situation of teenagers from the perspective of positive psychology. Therefore, this study explores the creativity level of Chinese college students during the COVID-19 pandemic, the relationship between sleep quality and creativity, and the mediating role of executive function.

Method

A cross-sectional study was conducted across six colleges in Heilongjiang in China, with a sample of 4,258 college students recruited via stratified cluster sampling. Data were collected through an online survey. A mediation model was constructed, and SPSS PROCESS macro was used to analyze the data.

Results

The creativity score of Chinese college students during the COVID-19 pandemic was 106.48 ± 13.61. Correlation analysis demonstrated that sleep quality correlated negatively with creativity (r = -0.08, P < 0.01) but positively with executive function (r=0.45, P < 0.01), whilst executive function correlated negatively with creativity (r = -0.10, P < 0.01). Moreover, the mediation model revealed that executive function partially mediated the relationship between sleep quality and creativity in college students (indirect effect = -0.017, SE = 0.004, 95% CI = [-0.025, -0.008]). Executive function accounted for 48.6% of the variance in college students' creativity.

Conclusion

School administrators should implement measures such as sleep education to enhance students' sleep quality. Concurrently, curriculum and assessment implementation should enhance executive function. Such measures can contribute to improved student creativity, thus helping students overcome the negative emotional impact of the COVID-19 pandemic.

Effects of partial sleep deprivation on prefrontal cognitive functions in adolescents

Purpose

The effect of sleep deprivation on cognitive functions associated with the frontal lobe, such as attention, executive functions, and working memory, is not well known. This study aimed to investigate the effect of partial sleep deprivation in adolescents on the cognitive tasks of the frontal lobe, including visuospatial working memory, processing speed, sustained attention, executive functions, and short-term visual memory.

Methods

Participants were recruited from voluntary students of Çukurova University. Eighteen adolescents underwent four consecutive nights of monitored sleep restriction (6-6.5 h/night) and four nights of sleep extension (10-10.5 h/night) in a counterbalanced order and separated by a washout period. Following each sleep period, the cognitive performance was assessed, at a fixed morning time, using a computerized neuropsychological test battery based on frontal lobe functions tasks, which was a timed test providing both accuracy and reaction time outcome measures.

Results

Only the spatial working memory performance of cognitive tasks was found to be statistically lower in the restricted-sleep condition than in the extended-sleep condition (p < 0.05). No significant difference was found in the performance of cognitive tasks evaluating simple attention, constant attention, executive functions, and cognitive flexibility.

Conclusions

The findings of this study indicated that partial sleep restriction negatively affects specifically working memory and strategic thinking skills among cognitive functions based on the frontal lobe. Especially the visuospatial working memory and strategic thinking skills of adolescents might be susceptible to chronic partial sleep deprivation.

Associations between sleep deficit and academic achievement - triangulation across time and subject domains among students and teachers in TIMSS in Norway

BACKGROUND

Sufficient sleep is important to an individual's health and well-being, but also for school achievement among adolescents. This study investigates the associations between sleepiness, sleep deficits, and school achievements among adolescents.

METHODS

This trend study involved a representative sample of Norwegian adolescents based on the "Trends in International Mathematics and Science Study" (TIMSS), N = 4499 (2015) and N = 4685 (2019) and their teachers. The students were 9th graders from a Norwegian compulsory secondary school. The survey included questions on students' sleepiness as students reported in 2019 and sleep deficits among students that limited teaching in class as their teachers reported in 2015 and 2019. Regression, triangulation, and mediation analyses were used. Mplus was used to perform the statistical analyses.

RESULTS

The results revealed significant negative associations between sleep deficits and school achievements, adjusted for gender, socioeconomic status (SES), and minority status among Norwegian 9th graders. These results were found for both mathematics and science achievements in 2015 and 2019. Sleepiness that the students reported was negatively associated with school achievements in 2019. Trend and mediation analyses showed that sleep deficits explained 18 and 11% of the decrease in mathematics and science achievements, respectively, from 2015 to 2019.

CONCLUSIONS

Sleep deficits were associated with school achievements in mathematics and science among Norwegian 9th graders. Mediation analyses revealed that sleep deficits explained a significant part of the decline in academic achievements. Insufficient sleep may have negative public health implications and influence adolescents' academic achievements and competences, and should therefore be discussed in both the educational and health systems.

The association between sleep disturbances and neurocognitive function in pediatric sickle cell disease

BACKGROUND AND OBJECTIVE

Youth with sickle cell disease (SCD) without neurological complications continue to be at increased risk of neurocognitive difficulties. Nocturnal hypoxemia is associated with neurocognitive outcomes and has been identified as a chronic complication in youth with SCD. The objective of this study was to assess the relationship between sleep disturbances and neurocognitive functioning in youth with SCD, while taking into account demographic and socioeconomic factors.

METHODS

Youth with SCD were identified through retrospective chart review who underwent a standardized polysomnography (PSG) and completed a neuropsychological testing battery to assess cognitive skills, including verbal comprehension, working memory, processing speed, and cognitive flexibility. Questionnaires were also collected to assess parent-reported concerns with their youth's executive and adaptive skills.

RESULTS

Twenty-seven youth with SCD, ages 6-17, were identified who completed both a PSG and neuropsychological testing. Results demonstrated that verbal comprehension decreased by 2.37 standard points for every unit decrease in mean nocturnal oxygen saturation (SpO2) (p = 0.031). Working memory was also found to decrease by 1.46 standard points for each 1% increase in time spent under 90% oxygen saturation (pTST SpO2 < 90%) (p = 0.030). Sleep parameters did not significantly predict other cognitive scores or parent-reported executive or behavioral ratings.

CONCLUSION

Our study found that sleep disturbance, mean nocturnal SpO2 and pTST SpO2 < 90%, significantly affected verbal comprehension and working memory performance, respectively. Overall, these findings have the potential to identify sleep needs in youth with SCD to promote sleep-targeted interventions as a modifiable factor to reduce neurocognitive deficits.

Sleep well, mind wander less: A systematic review of the relationship between sleep outcomes and spontaneous cognition

Despite an upsurge of research on spontaneous cognition, little is known about its associations with sleep-related outcomes. This systematic review, following PRISMA guidelines, examined the relationship between sleep and spontaneous thoughts, across different definitions and measurements of sleep outcomes and spontaneous cognition, and a diversity of methodologies. Twenty-one articles with survey and/or experimental designs were identified. Self-reported disturbed sleep-comprising poor sleep quality, more insomnia symptoms, more daytime sleepiness and a tendency towards eveningness-and experimentally induced sleep deprivation were associated with a tendency to engage in disruptive mind wandering and daydreaming, but not positive-constructive daydreaming. Findings regarding circadian fluctuation in spontaneous thoughts were mixed and inconclusive. This systematic review bridges the gap between the sleep and spontaneous cognition research by contributing to the understanding of potential psychological and cognitive mechanisms of spontaneous cognition, as well as by elucidating the emotional and cognitive consequences of disturbed sleep.

Sleep and Cognition: A Narrative Review Focused on Older Adults

Little is known regarding sleep's association with the traditional developmental course of late-life cognitive functioning. As the number of older adults increases worldwide, an enhanced understanding of age-related changes in sleep and cognition is necessary to slow decline and promote optimal aging. This review synthesizes the extant literature on sleep and cognitive function in healthy older adults, older adults with insomnia, and older adults with sleep apnea, incorporating information on the potential promising effects of treating poor sleep on cognitive outcomes in older adults. Unifying theories of the sleep-cognition association, possible mechanisms of action, and important unanswered questions are identified.

Bright light exposure during simulated night work improves cognitive flexibility

Night work leads to sleepiness and reduced vigilant attention during work hours, and bright light interventions may reduce such effects. It is also known that total sleep deprivation impairs cognitive flexibility as measured by reversal learning tasks. Whether night work impairs reversal learning task performance or if bright light can mitigate reversal learning deficits during night work is unclear. In this counterbalanced crossover study (ClinicaTrials.gov Identifier NCT03203538), young healthy individuals completed a reversal learning task twice during each of three consecutive simulated night shifts (23:00-07:00 h). The night shifts were performed in a laboratory under a full-spectrum (4000 K) bright light (~900 lx) and a standard light (~90 lx) condition. Reversal learning task performance was reduced towards the end of the night shifts (04:50 h), compared to the first part of the night shifts (00:20 h) in both light conditions. However, with bright light, the reversal learning task performance improved towards the end of the night shifts, compared to standard light. The study shows that bright light may mitigate performance deficits on a reversal learning task during night work and implies that bright light interventions during night work may be beneficial not only for vigilant attention but also for cognitive flexibility.

Planning Ability and Alertness After Nap Deprivation: Beneficial Effects of Acute Moderate-Intensity Aerobic Exercise Greater Than Sitting Naps

Nap deprivation is regarded as a sleep loss for habitual nappers. The beneficial effects of napping and moderate-intensity aerobic exercise on the reduction in planning ability following nighttime sleep deprivation have been proven. However, it is still unknown whether it can improve the performance decline caused by daytime nap deprivation in habitual nappers. Seventy-four healthy adults who had a long-term habit of taking naps were assigned to three interventions after receiving nap deprivation: (1) Control group (no intervention); (2) Nap group (15-min sitting naps); (3) Exercise group (15-min aerobic exercise), in which subjective alertness, mood, fatigue, and task performance in objective alertness (Psychomotor Vigilance Task, PVT) and planning ability (the Tower of London Task) were measured. Results showed that nap deprivation negatively influenced some performance on the psychomotor vigilance (i.e., response times and 10% slowest response time) and planning ability (i.e., planning time). And acute moderate-intensity aerobic exercise improved psychomotor alertness (i.e., response times) and planning ability (i.e., execution accuracy, execution time), a 15-min sitting naps only alleviated subjective fatigue, whereas some performance (i.e., response times) deteriorated when no intervention was used. These findings suggested that acute moderate-intensity aerobic exercise has a better restorative effect on the reduced planning ability and objective alertness due to nap deprivation compared to sitting naps.

Parenting and maternal reported child sleep problems in infancy predict school-age aggression and inattention

OBJECTIVE

To examine caregiving predictors of maternal reported sleep problems and child behavioral and cognitive outcomes in early childhood.

DESIGN

A prospective longitudinal study from 6 to 84 months of age.

SETTING

Lab visits, assessments, and questionnaires conducted with a community-based sample.

PARTICIPANTS

One hundred sixty-four African American and White children, their mothers, and teachers.

MEASUREMENT

Parenting behavior was measured during a free-play task at 6 months of age, maternal-report of child sleep problems was completed at 6 timepoints, and teacher report of child aggression and attention was collected in kindergarten and second grade.

RESULTS

Latent growth curve modeling revealed that maternal reported sleep problems decreased in children from 18 to 84 months and harsh-intrusive parenting at 6 months predicted sleep problems at 18 months. Maternal reported sleep problems at 18 months predicted aggressive behaviors in kindergarten and second grade.

CONCLUSION

Parenting at 6 months of age exerts an influence on sleep quality at 18 months which is associated with aggressive behavior in early childhood.

Self-Reported Sleep and Executive Function in Early Primary School Children

The study investigated the associations between children’s self-reported habitual sleep disturbance and multidimensional executive function (EF). Two hundred and four 7–9-year-old typically developing children completed the Sleep Self-Report and finished the Red-Blue Test, Wisconsin Card Sorting Test, and Backward Digit Span Test, indexing different EF components including inhibitory control, cognitive flexibility, and working memory. Results revealed that all the three EF components were significantly correlated with sleep. However, cognitive flexibility was no longer significantly related to sleep when the other EF components – inhibitory control and working memory – were controlled for. Meanwhile, inhibitory control, as well as working memory, was still significantly related to sleep after controlling for the other EF components. Results suggest that children’s self-reported sleep might be associated directly with inhibitory control and working memory, but indirectly with cognitive flexibility.

Sleep and circadian rhythm actigraphy measures, mood instability and impulsivity: A systematic review

The normal spectrum trait measures of mood instability and impulsivity are implicated in and comprise core symptoms of several psychiatric disorders. A bidirectional relationship between these traits and sleep disturbance and circadian rhythm dysfunction has been hypothesised, although has not been systematically assessed using objective measures in naturalistic settings. We systematically reviewed the literature following PRISMA guidelines, according to a pre-registered protocol (PROSPERO: CRD 42018108213). Peer-reviewed quantitative studies assessing an association between actigraphic variables and any measure of mood instability or impulsivity in participants aged 12-65 years old were included. Studies were critically appraised using the AXIS tool. Twenty-three articles were retained for inclusion. There was significant heterogeneity in the selection and reporting of actigraphic variables and metrics of mood instability and impulsivity. We identified emerging evidence of a positive association between circadian rest-activity pattern disturbance and delayed sleep timing with both mood instability and impulsivity. Evidence for an association with sleep duration, sleep efficiency or sleep quality was inconsistent. Future research should focus on longitudinal intra-individual associations to establish the directionality between these measures and may lead to the development of chronotherapeutic interventions for a number of psychiatric disorders.

Characteristics of Children Likely to Have Spontaneous Resolution of Obstructive Sleep Apnea: Results from the Childhood Adenotonsillectomy Trial (CHAT)

OBJECTIVE

To evaluate if cardiopulmonary coupling (CPC) calculated sleep quality (SQI) may have a role in identifying children that may benefit from other intervention than early adenotonsillectomy (eAT) in management of obstructive sleep apnea (OSA).

METHODS

A secondary analysis of electrocardiogram-signals (ECG) and oxygen saturation-data (SpO₂) collected during polysomnography-studies in the prospective multicenter Childhood Adenotonsillectomy Trial (CHAT) to calculate CPC-SQI and apnea hypopnea index (AHI) was executed. In the CHAT, children 5-9 years with OSA without prolonged oxyhemoglobin desaturations were randomly assigned to adenotonsillectomy (eAT) or watchful waiting with supportive care (WWSC). The primary outcomes were to document change in attention and executive function evaluated with the Developmental Neuropsychological Assessment (NEPSY). In our analysis, children in the WWSC-group with spontaneous resolution of OSA (AHI_Obstructive < 1.0) and high-sleep quality (SQI ≥ 75) after 7-months were compared with children that showed residual OSA.

RESULTS

Of the 227 children randomized to WWSC, 203 children had available data at both baseline and 7-month follow-up. The group that showed resolution of OSA at month 7 (n = 43, 21%) were significantly more likely to have high baseline SQI 79.96 [CI_95% 75.05, 84.86] vs. 72.44 [CI_95% 69.50, 75.39], p = 0.005, mild OSA AHI_Obstructive 4.01 [CI_95% 2.34, 5.68] vs. 6.52 [CI_95% 5.47, 7.57], p= 0.005, higher NEPSY-attention-executive function score 106.22 [CI_95% 101.67, 110.77] vs. 101.14 [CI_95% 98.58, 103.72], p = 0.038 and better quality of life according to parents 83.74 [CI_95% 78.95, 88.54] vs. 77.51 [74.49, 80.53], p = 0.015. The groups did not differ when clinically evaluated by Mallampati score, Friedman palate position or sleep related questionnaires.

CONCLUSIONS

Children that showed resolution of OSA were more likely to have high-SQI and mild OSA, be healthy-weight and have better attention and executive function and quality of life at baseline. As this simple method to evaluate sleep quality and OSA is based on analyzing signals that are simple to collect, the method is practical for sleep-testing, over multiple nights and on multiple occasions. This method may assist physicians and parents to determine the most appropriate therapy for their child as some children may benefit from WWSC rather than interventions. If the parameters can be used to plan care a priori, this would provide a fundamental shift in how childhood OSA is diagnosed and managed.

Shorter Duration and Lower Quality Sleep Have Widespread Detrimental Effects on Developing Functional Brain Networks in Early Adolescence

Sleep is critical for cognitive health, especially during complex developmental periods such as adolescence. However, its effects on maturating brain networks that support cognitive function are only partially understood. We investigated the impact of shorter duration and reduced quality sleep, common stressors during development, on functional network properties in early adolescence-a period of significant neural maturation, using resting-state functional magnetic resonance imaging from 5566 children (median age = 120.0 months; 52.1% females) in the Adolescent Brain Cognitive Development cohort. Decreased sleep duration, increased sleep latency, frequent waking up at night, and sleep-disordered breathing symptoms were associated with lower topological efficiency, flexibility, and robustness of visual, sensorimotor, attention, fronto-parietal control, default-mode and/or limbic networks, and with aberrant changes in the thalamus, basal ganglia, hippocampus, and cerebellum (P < 0.05). These widespread effects, many of which were body mass index-independent, suggest that unhealthy sleep in early adolescence may impair neural information processing and integration across incompletely developed networks, potentially leading to deficits in their cognitive correlates, including attention, reward, emotion processing and regulation, memory, and executive control. Shorter sleep duration, frequent snoring, difficulty waking up, and daytime sleepiness had additional detrimental network effects in nonwhite participants, indicating racial disparities in the influence of sleep metrics.

Sleep deprivation affects gait control

Different levels of sleep restriction affect human performance in multiple aspects. However, it is unclear how sleep deprivation affects gait control. We applied a paced gait paradigm that included subliminal rhythm changes to analyze the effects of different sleep restriction levels (acute, chronic and control) on performance. Acute sleep deprivation (one night) group exhibited impaired performance in the sensorimotor synchronization gait protocol, such as a decrease in the Period Error between the footfalls and the auditory stimulus as well as missing more frequently the auditory cues. The group with chronic sleep restriction also underperformed when compared to the control group with a tendency to a late footfall with respect to the RAC sound. Our results suggest that partial or total sleep deprivation leads to a decrease in the performance in the sensorimotor control of gait. The superior performance of the chronic sleep group when compared to the acute group suggests that there is a compensatory mechanism that helps to improve motor performance.

Sleep as a Moderator of Young Children's Traumatic Stress and Behavior Problems: a Treatment-Referred Sample

Empirical evidence suggests young children who have experienced trauma are at risk of developing sleep problems and behavior difficulties, but it is unclear of the specific relation between these behavioral health concerns. The primary purpose of the study is to determine whether sleep problems moderate the relation between traumatic stress and behavior problems in a sample of young children referred for treatment. A secondary purpose is to explore if sleep problems also moderate the relation between specific domains of traumatic stress (i.e., intrusion, avoidance, arousal) and behavior problems. Data from 170 preschoolers ages 3 through 5 referred for treatment were gathered at intake and utilized in this study. Results indicate sleep problems moderate the effect of overall traumatic stress on behavior problems. This statistical finding also was found with intrusive symptoms, and the moderation analyses approached significance with avoidance and arousal. Our findings highlight the importance for clinicians to assess for sleep problems when young children who have experienced trauma are referred to them for treatment, particularly if a low level of overall traumatic stress is present.

The role of prior sleep for divergent thinking in infants

Higher-order cognitive functions seem particularly vulnerable to disruptions in prior sleep in school-aged children and adult populations. This study tested whether divergent thinking in infants varied as a function of prior sleep. Forty-three infants aged 13-16 months participated in a behavioural assessment of divergent thinking. Length of wakefulness since last sleep was experimentally manipulated. In addition, potential relations between divergent thinking and sleep quantity and quality during the night immediately before the assessment, as well as during three consecutive nights preceding the assessment, were examined using actigraphy recordings in combination with parent diaries. Divergent thinking was not impaired by lack of sleep within the previous 4 h. Divergent thinking was consistently related to night-time sleep quality and quantity prior to the assessment. These results suggest that timing of prior naturally occurring daytime sleep is less relevant for emergent divergent thinking capacity than quality and quantity of preceding night-time sleep.

Sleep in Normal Aging, Homeostatic and Circadian Regulation and Vulnerability to Sleep Deprivation

In the context of geriatric research, a growing body of evidence links normal age-related changes in sleep with many adverse health outcomes, especially a decline in cognition in older adults. The most important sleep alterations that continue to worsen after 60 years involve sleep timing, (especially early wake time, phase advance), sleep maintenance (continuity of sleep interrupted by numerous awakenings) and reduced amount of sigma activity (during non-rapid eye movement (NREM) sleep) associated with modifications of sleep spindle characteristics (density, amplitude, frequency) and spindle-Slow Wave coupling. After 60 years, there is a very clear gender-dependent deterioration in sleep. Even if there are degradations of sleep after 60 years, daytime wake level and especially daytime sleepiness is not modified with age. On the other hand, under sleep deprivation condition, older adults show smaller cognitive impairments than younger adults, suggesting an age-related lower vulnerability to extended wakefulness. These sleep and cognitive age-related modifications would be due to a reduced homeostatic drive and consequently a reduced sleep need, an attenuation of circadian drive (reduction of sleep forbidden zone in late afternoon and wake forbidden zone in early morning), a modification of the interaction of the circadian and homeostatic processes and/or an alteration of subcortical structures involved in generation of circadian and homeostatic drive, or connections to the cerebral cortex with age. The modifications and interactions of these two processes with age are still uncertain, and still require further investigation. The understanding of the respective contribution of circadian and homeostatic processes in the regulation of neurobehavioral function with aging present a challenge for improving health, management of cognitive decline and potential early chronobiological or sleep-wake interventions.

Stability of neocortical synapses across sleep and wake states during the critical period in rats

Sleep is important for brain plasticity, but its exact function remains mysterious. An influential but controversial idea is that a crucial function of sleep is to drive widespread downscaling of excitatory synaptic strengths. Here, we used real-time sleep classification, ex vivo measurements of postsynaptic strength, and in vivo optogenetic monitoring of thalamocortical synaptic efficacy to ask whether sleep and wake states can constitutively drive changes in synaptic strength within the neocortex of juvenile rats. We found that miniature excitatory postsynaptic current amplitudes onto L4 and L2/3 pyramidal neurons were stable across sleep- and wake-dense epochs in both primary visual (V1) and prefrontal cortex (PFC). Further, chronic monitoring of thalamocortical synaptic efficacy in V1 of freely behaving animals revealed stable responses across even prolonged periods of natural sleep and wake. Together, these data demonstrate that sleep does not drive widespread downscaling of synaptic strengths during the highly plastic critical period in juvenile animals. Whether this remarkable stability across sleep and wake generalizes to the fully mature nervous system remains to be seen.

Impaired psychomotor vigilance associated with sleep-disordered breathing in women working in the care of older adults in Japan

PURPOSE

With a rapidly aging society, there is increasing interest in the health of female workers in the field of care services for older adults due to increasing demands to maintain 24-h care and to support older adults without errors or accidents. Therefore, the purpose of this cross-sectional study was to examine the association between sleep-disordered breathing (SDB) and sustained attention in women caring for older adults in Japan.

METHODS

The study was conducted in women aged 18-67 years old working in care service facilities for older adults in Japan. The sustained attention of participants was measured by the 10-min psychomotor vigilance task (PVT). SDB was assessed based on the respiratory disturbance index (RDI), which was measured using an ambulatory airflow monitor with a polyvinylidene fluoride (PVDF) film sensor to monitor the respiratory airflow of nasal and oral breathing. The participants wore the monitor to record the breathing status while asleep at home. The severity of SDB was categorized as follows: normal, RDI < 5 events/h; mild SDB, RDI 5-10 events/h; and moderate-to-severe SDB, RDI ≥ 10 events/h.

RESULTS

Of 688 women enrolled, medians of age, body mass index (BMI), sleep duration, and prevalence of hypertension tended to be higher with increasing RDI. No significant association was found between RDI and PVT parameters. However, when we limited the analysis to women with BMI ≥ 22 kg/m², those with moderate-to-severe SDB had significantly higher odds of having the slowest 10% reaction times compared to those without SDB (OR = 2.03; 95% CI = 1.17-3.53). The association did not decrease after adjusting to account for sleep duration, alcohol drinking habits, and history of hypertension (OR = 1.97; 95% CI = 1.10-3.52). A significant increasing trend was also found between RDI and the slowest 10% of reaction times (p for trend = 0.03).

CONCLUSIONS

Our findings suggest that SDB is associated with reduced sustained attention in participants with BMI ≥ 22 kg/m², although the number of assessments of SDB and PVT was only once per participant due to the nature of the cross-sectional study.

Trajectories of sleep problems in childhood: associations with mental health in adolescence

STUDY OBJECTIVES

We examined initial levels (intercepts) of sleep-wake problems in childhood and changes in sleep-wake problems across late childhood (slopes) as predictors of externalizing behavior problems, depressive symptoms, and anxiety in adolescence. To ascertain the unique effects of childhood sleep problems on adolescent mental health, we controlled for both childhood mental health and adolescent sleep problems.

METHODS

Participants were 199 youth (52% boys; 65% White/European American, 35% Black/African American). Sleep-wake problems (e.g. difficulty sleeping and waking up in the morning) were assessed during three time points in late childhood (ages 9, 10, and 11) with self-reports on the well-established School Sleep Habits Survey. At age 18, multiple domains of mental health (externalizing behavior problems, depressive symptoms, and anxiety) and sleep-wake problems were assessed.

RESULTS

Latent growth curve modeling revealed that children with higher levels of sleep-wake problems at age 9 had consistently higher levels of such problems between ages 9 and 11. The initial level of sleep-wake problems at age 9 predicted externalizing behaviors, depressive symptoms, and anxiety at age 18, controlling for mental health in childhood and concurrent sleep-wake problems in adolescence. The slope of sleep-wake problems from ages 9 to 11 did not predict age 18 mental health.

CONCLUSIONS

Youth who had higher sleep-wake problems during late childhood had higher levels of mental health problems in adolescence even after controlling for childhood mental health and concurrent sleep-wake problems. Findings illustrate that childhood sleep problems may persist and predict adolescent mental health even when potentially confounding variables are rigorously controlled.

Children's sleepiness facilitates the effect of vicarious learning on the development of fear

A substantial body of research demonstrates the importance of sleep for emotional processing and learning as well as the association between sleep problems and heightened anxiety. However, there is currently no research exploring the impact of sleepiness on vicariously learned fear responses. Experiment 1 (N = 38) first demonstrated no effect of trait or state sleepiness on children's (7-11 years of age) subjective ratings of fear. Experiment 2 (N = 42) and Experiment 3 (N = 46) used an established vicarious learning paradigm to demonstrate that trait sleepiness facilitated vicariously acquired avoidance preferences for animals paired with fearful faces (fear-paired animals), whereas state sleepiness facilitated children's fear cognitions and attentional bias toward fear-paired animals. This study is the first to demonstrate the role of state and trait sleepiness in moderating vicarious fear learning in children.

Experimental sleep restriction increases latency jitter in pain elicited cortical responses

Objective

Previous studies have shown increased pain scores to painful stimulation after experimental sleep restriction, but reduced or unchanged magnitude of the event related potentials (ERPs) when averaged in the time-domain. However, some studies found increased response magnitude when averaging in the time-frequency domain. The aim of this study was to determine whether ERP-latency jitter may contribute to this discrepancy.

Methods

Ninety painful electrical stimuli were given to 21 volunteers after two nights of 50% sleep restriction and after two nights of habitual sleep. ERPs were analyzed in the time-domain (N2-and P2-peaks) and time-frequency domain (power spectral density). We quantified latency jitter by the mean consecutive difference (MCD) between single-trial peak latencies and by phase locking value (PLV) across trials.

Results

P2-MCD increased from 20.4 ± 2.1 ms after habitual sleep to 24.3 ± 2.2 ms after sleep restriction (19%, p = 0.038) and PLV decreased from 0.582 ± 0.015 after habitual sleep to 0.536 ± 0.015 after sleep restriction (7.9%, p = 0.009). We found no difference for N2-MCD.

Conclusions

Our results indicate that partial sleep restriction increase latency jitter in cortical responses to experimental pain.

Significance

Latency jitter may contribute to the discrepancies between ERP-responses in the time-frequency domain and time-domain. Latency jitter should be considered when ERPs are analyzed.

Negative mood is associated with decreased prefrontal cortex functioning during working memory in young adults

The prefrontal-subcortical model of emotion regulation postulates that decreased prefrontal cortex (PFC) functioning may underlie the emergence of clinical affective disorders. In addition, accumulated evidence suggests that there is considerable variability in negative affect in the nonclinical population. This study examined whether negative affective symptoms were associated with decreased PFC functioning in nonclinical young adults. Forty college students aged 18-24 years (ten males) underwent an n-back paradigm (i.e., a frontal executive task) with a working memory (WM) load (i.e., 3-back) and a vigilance control condition (i.e., 0-back) while their hemodynamics changes in the lateral and medial PFC on both sides were monitored using a 16-channel functional near-infrared spectroscopy (fNIRS) system. They also filled out the Depression Anxiety Stress Scales (DASS) to estimate the levels of their negative emotions in the preceding week. Young adults exhibited an increased concentration of oxyhemoglobin and a decreased concentration of deoxyhemoglobin (i.e., activation), primarily in the lateral PFC, in response to the WM load (i.e., 3-back > 0-back). Importantly, higher DASS scores indicating higher levels of recent negative mood, especially depression and stress rather than anxiety symptoms, correlated with lower WM-related activation in the lateral PFC. Thus, recent negative mood is associated with decreased lateral PFC functioning during the executive control of WM in healthy young adults. Our findings suggest that decreased PFC functioning is also present in the nonclinical population with increased levels of negative mood and that fNIRS is a promising tool for elucidating individual differences in negative affective symptoms.

The Impact of Obstructive Sleep Apnea on Balance, Gait, and Falls Risk: A Narrative Review of the Literature

Falls-related hospitalization and injury rates are steadily increasing globally due to a growth in the aging population, and the associated health problems that increase risk of falls. One such associated health problem is sleep disturbances and disorders. Recent cohort studies have shown that subjectively reported poor quality sleep is associated with an increased risk of falls. Obstructive sleep apnea (OSA) is a common sleep disorder characterized by the repetitive reductions, or cessation, of airflow. Some studies have shown that OSA impairs posture/balance and gait with nocturnal hypoxemia the likely main cause. Emerging evidence suggests that treating OSA by continuous positive airway pressure (CPAP) can improve gait, but no studies to date have examined the effect of CPAP on posture/balance. The overall control of balance relies on a complex interaction between several physiological functions including vestibular, muscle, visual, and cognitive functions. We postulate that OSA impacts balance by affecting these different systems to various degrees, with the nocturnal hypoxic burden likely playing an important role. Importantly, these impairments in balance/posture and possible falls risk may be alleviated by OSA treatment. Larger mechanistic studies are needed to properly elucidate how OSA affects falls risk and future large-scale randomized control trials are needed to determine the effectiveness of OSA treatment in reducing the risk of falls.

Effect of Sleep and Biobehavioral Patterns on Multidimensional Cognitive Performance: Longitudinal, In-the-Wild Study

Background

With nearly 20% of the US adult population using fitness trackers, there is an increasing focus on how physiological data from these devices can provide actionable insights about workplace performance. However, in-the-wild studies that understand how these metrics correlate with cognitive performance measures across a diverse population are lacking, and claims made by device manufacturers are vague. While there has been extensive research leading to a variety of theories on how physiological measures affect cognitive performance, virtually all such studies have been conducted in highly controlled settings and their validity in the real world is poorly understood.

Objective

We seek to bridge this gap by evaluating prevailing theories on the effects of a variety of sleep, activity, and heart rate parameters on cognitive performance against data collected in real-world settings.

Methods

We used a Fitbit Charge 3 and a smartphone app to collect different physiological and neurobehavioral task data, respectively, as part of our 6-week-long in-the-wild study. We collected data from 24 participants across multiple population groups (shift workers, regular workers, and graduate students) on different performance measures (vigilant attention and cognitive throughput). Simultaneously, we used a fitness tracker to unobtrusively obtain physiological measures that could influence these performance measures, including over 900 nights of sleep and over 1 million minutes of heart rate and physical activity metrics. We performed a repeated measures correlation (r_rm) analysis to investigate which sleep and physiological markers show association with each performance measure. We also report how our findings relate to existing theories and previous observations from controlled studies.

Results

Daytime alertness was found to be significantly correlated with total sleep duration on the previous night (r_rm=0.17, P<.001) as well as the duration of rapid eye movement (r_rm=0.12, P<.001) and light sleep (r_rm=0.15, P<.001). Cognitive throughput, by contrast, was not found to be significantly correlated with sleep duration but with sleep timing—a circadian phase shift toward a later sleep time corresponded with lower cognitive throughput on the following day (r_rm=–0.13, P<.001). Both measures show circadian variations, but only alertness showed a decline (r_rm=–0.1, P<.001) as a result of homeostatic pressure. Both heart rate and physical activity correlate positively with alertness as well as cognitive throughput.

Conclusions

Our findings reveal that there are significant differences in terms of which sleep-related physiological metrics influence each of the 2 performance measures. This makes the case for more targeted in-the-wild studies investigating how physiological measures from self-tracking data influence, or can be used to predict, specific aspects of cognitive performance.

Sleep development in preschool predicts executive functioning in early elementary school

This report investigates the role of normative developments in sleep during preschool years in the prediction of child EF performance at early school age. Sleep was assessed by actigraphy at ages 2, 3, and 4, and EF with behavioral tasks when children were in Grade 2. The results revealed that children whose sleep followed expected developmental trends more rapidly showed better EF performance: a more pronounced decrease in sleep duration between ages 2 and 4 predicted better subsequent working memory, whereas a more pronounced increase in sleep efficiency was predictive of better inhibitory control performance. These findings suggest that age-related development may be a key characteristic of sleep as it relates to children's executive skills.