Sleep in Normal Aging

Association of sleep quality with physical and psychological health indicators in overweight and obese rural Indians

Objective

To measure the association of sleep quality with physical (i.e., grip strength, functional mobility, balance) and psychological (depression, anxiety) health indicators in an overweight/obese population.

Methods

Baseline data of 2337 participants (1382 overweight/obese and 955 normal weight) from an aging cohort in rural southern India (CBR-SANSCOG) was analyzed retrospectively. Assessment tools included the Pittsburgh Sleep Quality Index (PSQI) for sleep quality, dynamometry for Hand Grip Strength (HGS), Timed Up-and-Go (TUG) for functional mobility, Chair Stand Test (CST) for lower limb strength, Geriatric Depression scale (GDS-30) for depressive symptoms and Generalized Anxiety Disorder scale (GAD-7) for anxiety symptoms. Linear regression models, adjusted for known confounders, were used to examine the association of sleep quality with the health parameters in overweight/obese and normal-weight groups.

Results

In the fully adjusted model, higher global PSQI score was associated with higher TUG time (β = 0.06, 95 % CI: 0.004,0.12), higher scores on GDS (β = 1.08, 95 % CI: 0.96,1.20) and GAD (β = 0.71, 95 % CI: 0.62,0.79), and lower scores on CST (β = -0.12, 95 % CI: -0.19,-0.06) in overweight/obese individuals. The sleep disturbance sub-component of PSQI was associated with most of the physical (TUG, CST) and psychological (GDS and GAD) health indicators. Sleep duration and use of sleep medication showed no significant association with any of the health indicators.

Conclusion

The concurrent presence of poor sleep quality and overweight/obesity could worsen physical and psychological health in middle-aged and older adults. We highlight the importance of early detection and timely management of sleep problems in this population to reduce physical and psychological morbidities.

Circadian rhythm disruption and retinal dysfunction: a bidirectional link in Alzheimer's disease?

Dysfunction in circadian rhythms is a common occurrence in patients with Alzheimer's disease. A predominant function of the retina is circadian synchronization, carrying information to the brain through the retinohypothalamic tract, which projects to the suprachiasmatic nucleus. Notably, Alzheimer's disease hallmarks, including amyloid-β, are present in the retinas of Alzheimer's disease patients, followed/associated by structural and functional disturbances. However, the mechanistic link between circadian dysfunction and the pathological changes affecting the retina in Alzheimer's disease is not fully understood, although some studies point to the possibility that retinal dysfunction could be considered an early pathological process that directly modulates the circadian rhythm.

Promoting healthy sleep among older adults

As people age, their sleep patterns and needs naturally change in response to developmental and health-related factors. However, attaining sufficient restorative sleep remains crucial for overall well-being in older adults. This manuscript provides an overview of common sleep alterations that tend to emerge with advancing age, such as shifts in circadian rhythms, decreases in deeper sleep stages, fragmented sleep architecture and an association between comorbidities and sleep disruption. Practical recommendations that target environmental, behavioral and lifestyle modifications may optimize sleep initiation, maintenance, and duration for the older population. By enhancing understanding of the sleep changes that occur in the aged population, geriatric nurses are better able to provide respectful, patient-centered care to older adults that are experiencing sleep difficulties.

Actigraphic monitoring of sleep and circadian rest-activity rhythm in individuals with major depressive disorder or depressive symptoms: A meta-analysis

BACKGROUND

Disrupted sleep and rest-activity pattern are common clinical features in depressed individuals. This meta-analysis compared sleep and circadian rest-activity rhythms in people with major depressive disorder (MDD) or depressive symptoms and healthy controls.

METHODS

Eligible studies were identified in five databases up to December 2023. The search yielded 53 studies with a total of 11,115 participants, including 4000 depressed participants and 7115 healthy controls.

RESULTS

Pooled meta-analyses demonstrated that depressed individuals have significantly longer sleep latency (SMD = 0.23, 95 % CI: 0.12 to 0.33) and wake time after sleep onset (SMD = 0.37, 95 % CI: 0.22 to 0.52), lower sleep efficiency (SMD = -0.41, 95 % CI: -0.56 to -0.25), more nocturnal awakenings (SMD = 0.58, 95 % CI: 0.29 to 0.88), lower MESOR (SMD = -0.54, 95 % CI: -0.81 to -0.28), amplitude (SMD = -0.33, 95 % CI: -0.57 to -0.09), and interdaily stability (SMD = -0.17, 95 % CI: -0.28 to -0.05), less daytime (SMD = -0.79, 95 % CI: -1.08 to -0.49) and total activities (SMD = -0.89, 95 % CI: -1.28 to -0.50) when compared with healthy controls.

LIMITATIONS

Most of the included studies reported separate sleep and activity parameters instead of 24-hour rest-activity rhythms. The variabilities among actigraphy devices and the types of participants recruited also impede precise comparisons.

CONCLUSIONS

The findings emerging from this study offered a better understanding of sleep and rest-activity rhythm in individuals with MDD or depressive symptoms. Future studies could advocate for deriving objective, distinctive 24-hour rest-activity profiles contributing to the risk of depression.

PROSPERO REGISTRATION NUMBER

CRD42021259780.

The training times of athletes could play a role in clinical sleep problems due to their associations with sleep difficulty scores

OBJECTIVES

Sleep is a key component of athletic recovery, yet training times could influence the sleep of athletes. The aim of the current study was to compare sleep difficulties in athletes across different training time groups (early morning, daytime, late evening, early morning plus late evening) and to investigate whether training time can predict sleep difficulties.

METHODS

Athletes from various sports who performed at a national-level (n = 273) answered the Athlete Sleep Screening Questionnaire (ASSQ) along with several other questionnaires related to demographics, exercise training, and mental health. From the ASSQ, a Sleep Difficulty Score (SDS) was calculated. Transformed SDS (tSDS) was compared across different training time categories using multiple one-way ANOVAs. A stepwise regression was then used to predict tSDS from various sleep-related factors.

RESULTS

SDSs ranged from none (31%), mild (38%), moderate (22%), and severe (9%). However, the one-way ANOVAs revealed training earlier or later vs. training daytime shifted the tSDS in a negative direction, a trend toward increased sleep difficulty. In particular, athletes training in the late evening (>20:00 or >21:00) had a significantly higher tSDS when compared to daytime training (p = .03 and p < .01, respectively). The regression model (p < .001) explained 27% of variance in the tSDS using depression score, age, training time, and chronotype score.

CONCLUSION

Among a heterogeneous sample of national-level athletes, 31% displayed moderate to severe SDSs regardless of their training time. However, when athletes trained outside daytime hours there was a tendency for the prevalence of sleep difficulties to increase.

Association between sleep quality and quality of life in Singapore

PURPOSE

Several studies have examined the relationship between sleep quality and health-related quality of life (HRQOL). However, there are a lack of generalizable data on this association in Singapore. Our study aimed to (1) investigate the association between sleep quality and HRQOL and (2) examine whether age moderated these associations.

METHODS

Data were obtained from nationwide Singapore Mental Health Study 2016 (n = 6126, response rate = 69.5%). Sleep quality was assessed using Pittsburgh Sleep Quality Index (PSQI) where higher scores indicate poorer sleep quality. HRQOL [Physical component summary (PCS) and Mental component summary (MCS)] were measured using 12-item Short-Form Survey. Associations were investigated using multivariable linear regression models, adjusted for sociodemographic, physical, and mental comorbidities. Interactions between age and sleep quality were examined by including interaction terms individually.

RESULTS

Poorer PSQI score was significantly associated with lower PCS (β = - 0.44) and lower MCS (β = - 0.73). Among PSQI components, lower PCS was significantly associated with subjective sleep quality (β = - 1.06), sleep duration (β = - 0.30), sleep disturbance (β = - 0.33), and daytime dysfunction (β = - 0.75). Lower MCS was significantly associated with subjective sleep quality (β = - 1.36), sleep latency (β = - 0.24), sleep disturbance (β = - 0.16), using of sleeping medication (β = - 1.12), and daytime dysfunction (β = - 2.08). Age moderated the association between PSQI score with PCS and MCS. Stronger association between PSQI score and MCS was observed in younger individuals (β = - 0.90) than older adults (β = - 0.45).

CONCLUSION

Our study found that poor sleep quality was associated with HRQOL of certain age groups more than others. Future studies may identify potential mediators to help people with chronic sleep problems.

Sleep duration and the risk of new-onset arthritis in middle-aged and older adult population: results from prospective cohort study in China

Background

The pain and sleep disorders caused by arthritis are health issues that have been re-emphasized with the aging population. However, the majority of research on arthritis and sleep disorders has focused on cases that have already been diagnosed with arthritis. This research aims to explore the correlation between sleep duration and new-onset arthritis in middle-aged and older adult individuals.

Methods

Utilizing data from the China Health and Retirement Longitudinal Study from baseline (2011) to the Wave 3 follow-up (2018), we conducted a 7-year longitudinal investigation targeting populations with valid sleep questionnaire records and without arthritis. Sleep duration was assessed from nighttime sleep and daytime nap records. The new-onset of arthritis was determined based on self-reported diagnosis. We employed different logistic regression models to consider the potential impact of sleep duration on arthritis and conducted mediation analyses to assess the involvement of BMI in the association between sleep duration and the new-onset risk of arthritis.

Results

Out of the 6,597 individuals analyzed in the cohort, 586 (8.9%) were diagnosed with new-onset arthritis. Median sleep duration was notably shorter in the new-onset arthritis group (6.63 vs. 6.41 h, p < 0.05). There was a notable negative correlation found between new-onset risk of arthritis and sleep duration, with each Interquartile Range (IQR) increment in sleep leading to a 16% risk reduction (OR: 0.864; 95% CI: 0.784-0.954). Stratified analyses revealed BMI as a potential modifier in the sleep-arthritis relationship (P for interaction = 0.05). Mediation analyses further showed that about 3.5% of the association was mediated by BMI. Additionally, the inclusion of sleep duration improved the arthritis predictive power of our model, with an IDI of 0.105 (0.0203, 0.1898) and an NRI of 0.0013 (0.0004, 0.0022) after adding sleep duration to the basic model.

Conclusion

In the middle-aged and older adult demographic of China, increased sleep duration is associated with a decreased new-onset risk of arthritis, with BMI potentially playing a role in mediating this connection.

Multi-night acoustic stimulation is associated with better sleep, amyloid dynamics, and memory in older adults with cognitive impairment

Sleep is a potential early, modifiable risk factor for cognitive decline and dementia. Impaired slow wave sleep (SWS) is pronounced in individuals with cognitive impairment (CI). Cognitive decline and impairments of SWS are bi-directionally linked in a vicious cycle. SWS can be enhanced non-invasively using phase-locked acoustic stimulation (PLAS), potentially breaking this vicious cycle. Eighteen healthy older adults (HC, agemean±sd, 68.3 ± 5.1) and 16 older adults (agemean±sd, 71.9 ± 3.9) with CI (Montreal Cognitive Assessment ≤ 25) underwent one baseline (sham-PLAS) night and three consecutive stimulation nights (real-PLAS). EEG responses and blood-plasma amyloid beta Aβ42/Aβ40 ratio were measured pre- and post-intervention, as was episodic memory. The latter was again evaluated 1 week and 3 months after the intervention. In both groups, PLAS induced a significant electrophysiological response in both voltage- and time-frequency analyses, and memory performance improved in association with the magnitude of this response. In the CI group, both electrophysiological and associated memory effects were delayed compared to the healthy group. After 3 intervention nights, electrophysiological response to PLAS was no longer different between CI and HC groups. Only in the CI sample, stronger electrophysiological responses were significantly associated with improving post-intervention Aβ42/Aβ40 ratios. PLAS seems to improve SWS electrophysiology, memory, and amyloid dynamics in older adults with CI. However, effects on memory require more time to unfold compared to healthy older adults. This indicates that PLAS may become a potential tool to ameliorate cognitive decline, but longer interventions are necessary to compensate for declining brain integrity. This study was pre-registered (clinicaltrials.gov: NCT04277104).

Sleep promotes T-cell migration towards CCL19 via growth hormone and prolactin signaling in humans

Sleep strongly supports the formation of adaptive immunity, e.g., after vaccination. However, the underlying mechanisms remain largely obscure. Here we show in healthy humans that sleep compared to nocturnal wakefulness specifically promotes the migration of various T-cell subsets towards the chemokine CCL19, which is essential for lymph-node homing and, thus, for the initiation and maintenance of adaptive immune responses. Migration towards the inflammatory chemokine CCL5 remained unaffected. Incubating the cells with plasma from sleeping participants likewise increased CCL19-directed migration, an effect that was dependent on growth hormone and prolactin signaling. These findings show that sleep selectively promotes the lymph node homing potential of T cells by increasing hormonal release, and thus reveal a causal mechanism underlying the supporting effect of sleep on adaptive immunity in humans.

Sleep Patterns in Patients After Solid Organ Transplantation Including Gender and Age Differences. Survey Results From One Transplantation Centre in Poland

INTRODUCTION

Sleep plays a crucial role in maintaining health. Transplant patients are exposed to numerous stressors and are at risk of sleep disturbances. The aim of this study was to assess the sleep patterns of transplant patients.

METHODS

An anonymous paper survey was carried out among patients from one transplant center in Poland. Respondents were asked about the quality and quantity of sleep and the overall impact of the transplantation on their night rest. Data were collected from June to November 2023.

RESULTS

Data were obtained from 212 respondents (122 males and 90 females), aged 48.38 ± 13.68. The positive impact of transplantation on sleep hygiene was indicated by 57.4% of respondents, 28.9% observed no impact, and 13.6% rated the impact as negative. Our study showed that sleep is more satisfying in males than in females (62.8% of males and 46.7% of females). The analysis revealed that 38.9% of females need 30 minutes more than men to fall asleep. Additionally, females tend to get up half an hour later compared to men. About 71.9% of males declared good well-being the next day compared to 62.2% of females. Furthermore females declared more sleepiness the next day. The study also showed that older transplant recipients (over 50 years-of-age) report more frequent awakenings at night.

CONCLUSIONS

The data collected showed differences in sleep patterns according to gender and age. Females and older patients should be screened for sleep disturbances during post-transplantation care.

Serotonergic dysfunction may mediate the relationship between alcohol consumption and Alzheimer's disease

The impact of Alzheimer's disease (AD) and its related dementias is rapidly expanding, and its mitigation remains an urgent social and technical challenge. To date there are no effective treatments or interventions for AD, but recent studies suggest that alcohol consumption is correlated with the risk of developing dementia. In this review, we synthesize data from preclinical, clinical, and epidemiological models to evaluate the combined role of alcohol consumption and serotonergic dysfunction in AD, underscoring the need for further research on this topic. We first discuss the limitations inherent to current data-collection methods, and how neuropsychiatric symptoms common among AD, alcohol use disorder, and serotonergic dysfunction may mask their co-occurrence. We additionally describe how excess alcohol consumption may accelerate the development of AD via direct effects on serotonergic function, and we explore the roles of neuroinflammation and proteostasis in mediating the relationship between serotonin, alcohol consumption, and AD. Lastly, we argue for a shift in current research to disentangle the pathogenic effects of alcohol on early-affected brainstem structures in AD.

Association between self-perception of the neighborhood environment and sleep problems in older Brazilian adults: findings from ELSI-Brazil

This study aimed to investigate associations between neighborhood perception and sleep problems in older Brazilian adults. A cross-sectional study was conducted with 5,719 community-dwelling older adults (≥ 60 years) from the Brazilian Longitudinal Study of Aging (ELSI-Brazil, 2019-2021). The outcomes were self-reported sleep problems: poor sleep quality, daytime sleepiness, primary insomnia complaints, difficulty staying asleep, and waking up at dawn. The exposure variables were questions about the perception of participants about the physical and social environment of the neighborhood. Logistic regression was used in data analysis. Garbage, rubbish, or tall grass on the streets and the desire to move were associated with higher odds of poor sleep quality. Concern about falling due to damaged sidewalks, concern about having difficulties taking transportation, and concern about having difficulties crossing the street were associated with higher odds of all sleep problems. Sound/noise of buses and cars was associated with higher odds of some sleep problems. Perceiving the neighborhood as a good place to live was associated with lower odds of daytime sleepiness and primary insomnia complaints. Trusting most people in the neighborhood and perceiving that kids and younger people treat adults with respect were associated with lower odds of daytime sleepiness, primary insomnia complaints, and waking up at dawn. Being a good place for kids to play and raise teenagers was associated with lower odds of daytime sleepiness. These results can assist public administrators in creating urban planning policies aimed at improving neighborhood environments as a means of health promotion.

Efficacy of the Transdiagnostic Intervention for Sleep and Circadian Dysfunction for Depression Symptoms and Sleep-Wake Disruption in Older and Younger Adults: Secondary Age-Stratified Analysis of a Randomized Controlled Trial

OBJECTIVE

Perform a secondary analysis examining the efficacy of the Transdiagnostic Intervention for Sleep and Circadian Dysfunction (TranS-C) for depression symptom responses, and explore changes in potential target mechanisms.

DESIGN

Secondary analysis of a randomized controlled trial with convenience age subsamples (younger (20-49 year; n = 52) versus and older (50-71 years; n = 35)).

SETTING

Community mental health clinics.

PARTICIPANTS

Eighty-seven adults with serious mental illness.

INTERVENTION

TranS-C versus treatment as usual (TAU).

MEASUREMENTS

Outcomes were depression symptoms (Quick Inventory of Depression Symptoms), insomnia symptoms (Insomnia Severity Index), and objective sleep-wake rhythm measures (interdaily stability and relative amplitude).

RESULTS

Depression response rates (≥50% symptom reductions) were higher in the TranS-C (35.0%) than the TAU (8.8%) group 6-months postintervention (χ2 = 10.3, p = 0.001). There was a medium effect of TranS-C versus TAU on depression symptoms 6-months postintervention (Cohen's d = -0.40, 95% confidence interval (CI): -0.81, 0.01). In both age groups, there were large treatment effects on insomnia symptoms post-treatment (Cohen's d >0.90). In the older subsample, there were additionally medium treatment effects on post-treatment interdaily stability (Cohen's d = 0.60, 95% CI: -0.11, 1.61). Post-treatment reductions in insomnia symptoms correlated with depression symptom reduction 6-months later in the younger subsample (Spearman rho = 0.59, n = 20, p = 0.008). In older adults, postintervention increases in interdaily stability correlated with depression symptom reductions 6-months later (Spearman rho = -0.52, n = 15, p = 0.049).

CONCLUSION

Confirmatory trials are needed, given the low age-specific sample sizes here, to determine if TranS -C's produces durable depression responses by increasing sleep-wake rhythm stability in older adults and improving insomnia symptoms in younger adults.

BRIEF ARTICLE SUMMARY

The authors evaluated preliminary efficacy of a behavioral intervention that targets sleep/sleep-wake rhythms, the Transdiagnostic Intervention for Sleep and Circadian Dysfunction (TranS-C), for depression symptoms in people with serious mental illness. TranS-C was associated with higher depression response rates than treatment as usual 6-months postintervention. The degree of depression symptom response 6-months later was related to the degree of treatment phase improvements in interdaily stability (in older adults) and reduction in insomnia severity (in younger adults). A pragmatic nonpharmacologic intervention, the Transdiagnostic Intervention for Sleep and Circadian Dysfunction, has preliminary efficacy for improving sleep-wake factors and depression symptoms.

The Impact of Sleep Disturbances on Endogenous Pain Modulation: A Systematic Review and Meta-Analysis

The bidirectional relationship between sleep and pain problems has been extensively demonstrated but despite all the accumulating evidence, their shared mechanisms are currently not fully understood. This review examined the association between sleep disturbances, defined as a broad array of sleep-related outcomes (eg, poor quality, short duration, insomnia), and endogenous pain modulation (EPM) in healthy and clinical populations. Our search yielded 6,151 references, and 37 studies met the eligibility criteria. Qualitative results showed mixed findings regarding the association between sleep disturbances and temporal summation of pain (TSP) and conditioned pain modulation (CPM), with poor sleep more commonly associated with decreased pain inhibition in both populations. Quantitative results indicated that such associations were not statistically significant, neither in healthy populations when EPM outcomes were assessed for changes pre-/post-sleep intervention (TSP: .31 [95%CI: -.30 to .92]; P = .321; CPM: .40 [95%CI: -.06 to .85] P = .088) nor in clinical populations when such association was assessed via correlation (TSP: -.00 [95%CI: -.22 to .21] P = .970; CPM: .12 [95%CI: -.05 to .29]; P = .181). For studies that reported results by sex, meta-analysis showed that experimental sleep disturbances impaired pain inhibition in females (1.43 [95%CI: .98-1.88]; P < .001) but not in males (-.30 [95%CI: -2.69 to 1.60]; P = .760). Only one study investigating the association between sleep disturbances and offset analgesia was identified, while no studies assessing spatial summation of pain were found. Overall, this review provides a comprehensive overview of the association between sleep disturbances and EPM function, emphasizing the need for further investigation to clarify specific mechanisms and phenotypic subtypes. PERSPECTIVE: This review shines a light on the association between sleep disturbances and endogenous pain modulation function. Qualitatively, we found a frequent association between reduced sleep quality and impaired pain inhibition. However, quantitatively such an association was not corroborated. Sex-specific effects were observed, with females presenting sleep-related impaired pain inhibition but not males.

Parasomnias manifest different phenotypes of sleep-related behaviors in age and sex groups. A YouTube-based video research highlighting the age slope of sleepwalking

STUDY OBJECTIVE

Finding typical patterns - phenotypes - of sleep behaviors characterizing parasomnias in different age and sex groups.

METHODS

We analyzed YouTube videos on sleep-related behaviors likely representing parasomnias. We applied the search terms "sleepwalking", "somnambulism", "sleep eating", "sleep sex", "sleep talking", and "aggression in sleep" in six languages. We classified those persons shown on the videos into estimated biological sex and age (child, adult, elderly) groups. We scored the activity types by a self-made scale and applied binary logistic regression to analyze the association between sleep behaviors versus sex and age groups by the STATA package, providing a 95% confidence interval and the probability of statistical significance.

RESULTS

224 videos (102 women, 68 children, 16 adults, and 40 elderly people) were scored. Elderly people had significantly (P < 0.012) lower odds of sleepwalking compared to adults and children. Adult females performed complex manual activities during sleepwalking more often than males (P < 0.012). Elderly males had 40-fold odds compared to adults and children, to perform aggressive movements and 70-fold odds of complex movements in bed, compared to adults. Elderly people presented emotional behaviors less frequently than adults (P < 0.004), and females showed them twice as often as males. Adults sleep-talked full sentences more often than children and elderly people (P < 0.001).

CONCLUSION

Our results support the existence of age- and sex-specific parasomnia phenotypes, denoting possible safety measures. The remarkably low odds of sleepwalking in the elderly highlight the possibility of different pathomechanisms in higher age groups compared to children.

BRIEF SUMMARY AND STUDY IMPACT

Parasomnias present highly variable clinical forms and often cause injuries. Identifying typical phenotypes may help risk management and imply theoretical conclusions. Our study supports the existence of age-specific parasomnia phenotypes. We found that adult women have a high risk of performing dangerous activities during sleep, and elderly males often move violently in bed, likely representing dream enactment behaviors. Elderly people of both sexes have low odds of sleep ambulation- likely representing somnambulism; compared to adults and children, constituting a descending "age slope" of somnambulism that might reflect different underlying pathomechanisms in children versus adults and the elderly.

Association among cognitive function, daytime activities, and nighttime sleep in older adults in a long-term care facility

AIM

To determine how the nighttime sleep patterns of older adults in a long-term care facility vary according to cognitive function and participation in daytime activities.

METHODS

This observational study was conducted with older adults aged ≥65 years who are residents of a long-term care facility. Nighttime sleep was monitored using a non-wearable sleep monitor for 8 weeks. Based on the Mini-Mental State Examination scores for assessment of cognitive function, participants were classified into non-dementia, mild-to-moderate dementia, and severe dementia groups. The Mann-Whitney U test and Kruskal-Wallis test were used to analyze the data.

RESULTS

Twenty three older adults were included in this study. Sleep onset latency was significantly longer in the severe dementia group than in the non-dementia (p = .027) and mild-to-moderate dementia (p = .041) groups. Sleep efficiency was significantly lower in the severe dementia group than in the mild-to-moderate dementia group (p = .003), whereas wakefulness after sleep onset was significantly longer in the severe dementia group than in the mild-to-moderate dementia group (p = .011). The number of days spent engaging in recreational activities was <50%, whereas those spent taking a nap was >60% in all older adults. Older adults with mild-to-moderate dementia had better sleep and participated in more daytime activities than those with severe or no dementia. Moreover, bathing in a bathtub improved sleep onset latency.

CONCLUSIONS

This study demonstrates that participation in daytime activities and bathing in a bathtub affect nighttime sleep in older adults.

Self-reported physical activity and sleep quality is associated with working memory function in middle-aged and older adults during the COVID-19 pandemic

While previous work has shown a positive relationship between cognitive performance and lifestyle factors in younger adults, evidence for this relationship among middle-aged and older adults has been mixed. The current study aimed to further test the relationship among physical activity, sleep quality, and memory performance in middle-aged and older adults, and to test whether this relationship holds up during the COVID-19 pandemic. Our results showed that physical activity was associated with better sleep quality and better working memory performance, and better sleep quality was associated with better working memory and self-perceptions of everyday memory abilities. Additionally, we found that the effects of physical activity on working memory were partially mediated by sleep quality. While these effects were small and only correlational in nature, they lend further support to the notion that sleep quality and physical activity are beneficial to memory later in life, even during a global pandemic.

Mid-to-Late-Life Anxiety and Sleep during Initial Phase of COVID-19: Age- and Sex-Specific Insights to Inform Future Pandemic Healthcare

This study examined associations between COVID-19-related anxiety and sleep in middle-aged and older adults and tested whether these varied by age or sex. In June/July 2020, middle-aged/older adults aged 50+ (n = 277, 45% women, Mage = 64.68 ± 7.83) in the United States completed measures of sleep and COVID-19-related anxiety. Multiple regressions examined whether anxiety was independently associated with or interacted with age or sex in its associations with sleep health, controlling for age, education, medical conditions, sleep/pain medication use, and COVID-19 status. Greater COVID-19 anxiety was associated with worse sleep quality and daytime dysfunction. COVID-19-related anxiety interacted with age (not sex) in associations with total sleep time and sleep efficiency. Greater anxiety was associated with shorter total sleep time and lower sleep efficiency in oldest-older adults (~73 years old) and youngest-older adults (~65 years old) but not middle-aged adults (~57 years old). In mid to late life, older adults may be most vulnerable to the impact of COVID-19-related anxiety on sleep health. Social and behavioral (e.g., knowledge on age-related vulnerability to COVID-19 risk/morbidity/mortality, uncertainty, and changes to daily routines) and physiological factors (sleep disruption and age-related autonomic dysfunction) may underlie these associations. Interventions that mitigate negative pandemic-related psychological and sleep outcomes may be particularly relevant for older adults.

Inverted U-shaped relationship between sleep duration and phenotypic age in US adults: a population-based study

Sleep is a modifiable behavior that can be targeted in interventions aimed at promoting healthy aging. This study aims to (i) identify the sleep duration trend in US adults; (ii) investigate the relationship between sleep duration and phenotypic age; and (iii) explore the role of exercise in this relationship. Phenotypic age as a novel index was calculated according to biomarkers collected from US adults based on the National Health and Nutrition Examination Survey (NHANES). Sleep information was self-reported by participants and discerned through individual interviews. The principal analytical method employed was weighted multivariable linear regression modeling, which accommodated for the complex multi-stage sampling design. The potential non-linear relationship was explored using a restricted cubic spline (RCS) model. Furthermore, subgroup analyses evaluated the potential effects of sociodemographic and lifestyle factors on the primary study outcomes. A total of 13,569 participants were finally included in, thereby resulting in a weighted population of 78,880,615. An examination of the temporal trends in sleep duration revealed a declining proportion of individuals with insufficient and markedly deficient sleep time since the 2015-2016 cycle. Taken normal sleep group as a reference, participants with extreme short sleep [β (95% CI) 0.582 (0.018, 1.146), p = 0.044] and long sleep [β (95% CI) 0.694 (0.186, 1.203), p = 0.010] were both positively associated with phenotypic age using the fully adjusted model. According to the dose-response relationship between sleep duration and phenotypic age, long sleep duration can benefit from regular exercise activity, whereas short sleep duration with more exercise tended to have higher phenotypic age. There is an inverted U-shaped relationship between short and long sleep durations and phenotypic age. This study represents an important step forward in our understanding of the complex relationship between sleep and healthy aging. By shedding light on this topic and providing practical exercise recommendations for promoting healthy sleep habits, researchers can help individuals live longer, healthier, and more fulfilling lives.

Association between sleep traits and biological aging risk: a Mendelian randomization study based on 157 227 cases and 179 332 controls

STUDY OBJECTIVES

To investigate whether sleep traits are associated with the risk of biological aging using a case-control design with Mendelian randomization (MR) analyses.

METHODS

We studied 336 559 participants in the UK Biobank cohort, including 157 227 cases of accelerated biological aging and 179 332 controls. PhenoAge, derived from clinical traits, estimated biological ages, and the discrepancies from chronological age were defined as age accelerations (PhenoAgeAccel). Sleep behaviors were assessed with a standardized questionnaire. propensity score matching matched control participants to age-accelerated participants, and a conditional multivariable logistic regression model estimated odds ratio (OR) and 95% confidence intervals (95% CI). Causal relationships between sleep traits and PhenoAgeAccel were explored using linear and nonlinear MR methods.

RESULTS

A U-shaped association was found between sleep duration and PhenoAgeAccel risk. Short sleepers had a 7% higher risk (OR = 1.07; 95% CI: 1.03 to 1.11), while long sleepers had an 18% higher risk (OR = 1.18; 95% CI: 1.15 to 1.22), compared to normal sleepers (6-8 hours/day). Evening chronotype was linked to higher PhenoAgeAccel risk than morning chronotype (OR = 1.14; 95% CI: 1.10 to 1.18), while no significant associations were found for insomnia or snoring. Morning chronotype had a protective effect on PhenoAgeAccel risk (OR = 0.87, 95% CI: 0.79 to 0.95) per linear MR analysis. Genetically predicted sleep duration showed a U-shaped relationship with PhenoAgeAccel, suggesting a nonlinear association (pnonlinear < 0.001).

CONCLUSIONS

The study suggests that improving sleep can slow biological aging, highlighting the importance of optimizing sleep as an intervention to mitigate aging's adverse effects.

Sleep disturbances and change in multiple cognitive domains among older adults: a multicenter study of five Nordic cohorts

STUDY OBJECTIVES

We examined and compared cross-sectional and longitudinal associations between self-reported sleep disturbances and various cognitive domains in five separate Nordic European longitudinal aging studies (baseline N = 5631, mean age = 77.7, mean follow-up = 4.16 years).

METHODS

Comparable sleep parameters across studies included reduced sleep duration/quality, insomnia symptoms (sleep latency, waking up at night, and early awakenings), short and long sleep duration, and daytime napping. The cognitive domains were episodic memory, verbal fluency, perceptual speed, executive functioning, and global cognition (aggregated measure). A series of mixed linear models were run separately in each study and then compared to assess the level and rate of change in cognitive functioning across each sleep disturbance parameter. Models were adjusted for age, sex, education, hypnotic usage, depressive symptoms, lifestyle factors, cardiovascular, and metabolic conditions. By using a coordinated analytic approach, comparable construct-level measurements were generated, and results from identical statistical models were qualitatively compared across studies.

RESULTS

While the pattern of statistically significant results varied across studies, subjective sleep disturbances were consistently associated with worse cognition and steeper cognitive decline. Insomnia symptoms were associated with poorer episodic memory and participants sleeping less or more than 7-8 hours had a steeper decline in perceptual speed. In addition, daytime napping (>2 hours) was cross-sectionally and longitudinally associated with all examined cognitive domains. Most observed associations were study-specific (except for daytime napping), and a majority of association estimates remained significant after adjusting for covariates.

CONCLUSION

This rigorous multicenter investigation further supports the importance of sleep disturbance, including insomnia, long and short sleep duration, and daytime napping on baseline cognitive functioning and rate of change among older adults. These sleep factors may be targeted in future lifestyle interventions to reduce cognitive decline.

Association between sleep quality and blood pressure control among hypertensive patients at a rural tertiary hospital in Southern Nigeria: a cross-sectional study

OBJECTIVES

Restorative sleep is critical in preventing hypertension and other chronic diseases. Limited research has explored the relationship between sleep quality and hypertension in Africa. This study investigated the association between sleep quality and blood pressure control among hypertensive patients in Southern Nigeria.

DESIGN

Cross-sectional study.

SETTING

A rural tertiary hospital in Southern Nigeria, April to June 2023.

PARTICIPANTS

250 systematically selected hypertensive adults. Participants completed a validated semistructured interviewer-administered questionnaire to assess their sleep patterns, including sleep duration, self-reported trouble sleeping and a history of clinical diagnosis of sleep disorders. Sleep patterns were categorised as restorative (healthy) or non-restorative (unhealthy). The blood pressure of respondents was checked and categorised as controlled (<140/90 mm Hg) or uncontrolled (≥140/90 mm Hg). Data were analysed descriptively using SPSS V.24.0 OUTCOME MEASURES: Quality of sleep and blood pressure control.

RESULTS

Respondents had a mean age of 51.5±10.0 years, with the majority being female (156, 62.4%), married (135, 54.0%) and belonging to the Esan tribe (125, 50.0%). The prevalence of restorative sleep was 36%, while the blood pressure control rate was 23.6%. An association was found between restorative sleep and blood pressure control (adjusted OR =4.38; 95% CI=2.37-8.10; p<0.0001). Respondents aged ≥60 years had 3.5 times higher odds of experiencing non-restorative sleep than those aged ≤40 years (aOR=3.46; 95% CI=1.37-8.74; p=0.009).

CONCLUSION

The study found an association between poor quality sleep and poor blood pressure control. Incorporating sleep assessments and interventions into comprehensive hypertension management strategies could be explored as a possible approach to improve sleep quality and enhance blood pressure control.

TRIAL REGISTRATION NUMBER

PACTR202301917477205.

Aging Adults' Willingness, Preferences, and Access to Self-Hypnosis for Sleep: A Cross-Sectional Survey

Sleep disturbance is a public health problem among aging adults (age 45 and older). While aging adults are at an elevated risk for sleep disturbance, many also have high rates of mistrust toward psychological interventions, such as self-hypnosis, which may be beneficial for sleep. The purpose of the study was to assess factors that may impact utilization of self-hypnosis for sleep, including willingness, preferences, and access among informed aging adults. 244 aging adults were recruited. After reading an information sheet on self-hypnosis for sleep, participants completed questionnaires assessing sleep related worry, stress, and perceptions of self-hypnosis for sleep, including willingness, benefits, barriers, preferences, and access. The findings indicated that informed aging adults were willing to engage in self-hypnosis for sleep, regardless of their race or gender. Furthermore, they preferred technological delivery methods (i.e. telehealth or smartphone apps) with flexible scheduling options. However, very few participants endorsed having access to self-hypnosis.

Changes in Restless Sleep, Self-Control, and Alcohol-Related Problems with Police from Late Adolescence to Adulthood

Sleep quality is crucial for healthy adolescent brain development, which has downstream effects on self-control and involvement in risky behaviors, such as alcohol use. While previous studies have found that sleep and facets of self-control are associated with patterns of alcohol use, few have assessed whether these constructs are tied to alcohol-related problems with law enforcement during the transitional period from adolescence to adulthood. The current study uses self-report panel data from ages 16 to 27 from a population-based sample of U.S. youth (N = 956; 36.86% female). The goal of the current study is to assess the association between changes in restless sleep, impulsivity, sensation seeking, and problems with police during or shortly after consuming alcohol from adolescence to adulthood to begin to address this gap in the existing literature. Results from a multivariate latent growth curve model reveal that faster increases in restless sleep and slower declines in impulsivity are associated with slower declines in police contact. Correlated changes between restless sleep, impulsivity, and police contact are slightly greater from ages 16-21 than for ages 22-27, with males showing stronger associations. The reported results suggest that identifying developmental mechanisms between changes in poor sleep, impulsivity, and alcohol use behaviors during this life-course phase will be crucial moving forward to help divert youth away from alcohol-related contact with the police.

The impact of 5-hydroxytryptophan supplementation on sleep quality and gut microbiota composition in older adults: A randomized controlled trial

BACKGROUND & AIMS

Sleep quality is a pivotal part of health and there is growing evidence on the association between gut microbiota composition and sleep quality. 5-Hydroxytryptophan (5-HTP) is known as a precursor of the sleep regulating neurotransmitter and hormone. However, efficacy of 5-HTP supplementation for improving sleep quality in older adults is unclear. Hence, the aim of this study is to assess the impact of 5-HTP supplementation on sleep quality and gut microbiota composition in older adults.

METHODS

This is a single-blinded, 12-week parallel randomized controlled trial. Thirty older adults (66 ± 3 years) in Singapore were randomly assigned to either consume or not consume 100 mg 5-HTP daily. Every 4 weeks, sleep quality was assessed via both subjective (Pittsburg Sleep Quality Index) and objective (actigraphy watch) measures. A global sleep score (GSS) was obtained from the PSQI, where a GSS>5 defines as poor sleeper while a GSS≤5 defines as good sleeper. Blood serotonin level, urine melatonin concentration, gut microbiota composition and stool short chain fatty acids (SCFA) content were assessed at week 0 and 12. This study was registered in clinicaltrials.gov as NCT04078724 (https://clinicaltrials.gov/ct2/show/NCT04078724).

RESULTS

5-HTP supplementation showed an overall favorable effect on certain sleep quality components and an increase in serum serotonin concentration. In particular, at week 12, not good sleepers but poor sleepers with 5-HTP supplementation were able to significantly improve subjective GSS (ΔSL5-HTP: -2.80 ± 1.10 min, p-value = 0.005). In addition, they showed an increase in microbiota diversity (Simpson5-HTP vs. SimpsonControl: 0.037 ± 0.032 a.u. vs. -0.007 ± 0.022 a.u.; pinteraction: 0.013) and relative abundance of SCFA producing bacteria in the gut.

CONCLUSIONS

5-HTP supplementation can improve certain sleep quality components in older adults and this benefit was more prominently observed in poor sleepers. 5-HTP was also able to improve the gut microbiota composition in poor sleepers.

The early-stage impacts of shock events on adult sleep: Lessons from the COVID-19 pandemic

The present study aims to estimate the early-stage association of the coronavirus disease 2019 (COVID-19) pandemic with sleep duration, 4 months after the initial outbreak, at a national level. Using the China Family Panel Studies in 2018 and its follow-up in 2020, 16,563 adult participants were analyzed in our study. The first wave transmissibility of the COVID-19 pandemic in mainland China was used as a quasi-natural experiment. The difference in difference method was employed to compare variations across participants interviewed before or after the pandemic and between groups from provinces with different COVID-19 severity. The study observed a decline in workday sleep duration among adults, regardless of their employment status. Specifically, working adults experienced a significant decrease in sleep duration on work days (-1.54, 95% confidence interval -2.16 to -0.92), alongside an increase on work-free days (2.41, 1.56-3.24), leading to a wider sleep discrepancy in sleep patterns (3.95, 3.31-4.59). Noteworthy, working-age adults (-2.00, -2.79 to -1.22) and males (-3.31, -4.31 to -2.30) exhibited greater sleep decreases on work days, whereas females exhibited a more pronounced disparity in sleep patterns (6.18, 4.73-7.63) between work and work-free days. The pandemic is significantly associated with prolonged changes in adults' sleep duration, including sleep decreases on work days and catch-up sleep on work-free days for working adults. To prepare for future global emergencies, the government may need to promote resilience to mitigate the pandemic's adverse impacts on the working population. Guaranteeing adequate sleep among working adults and reducing sleep debt should be prioritized in such efforts.

Persistently short or long sleep duration increases the risk of sensory impairment in Chinese older adults

Background

Cross-sectional evidence suggests that persistently short or long sleep duration is associated with sensory impairment. Thus, this study was conducted to investigate the associations between sleep duration and altered sleep duration with sensory impairment in Chinese older adults.

Methods

Longitudinal data (2008-2014) obtained through the Chinese Longitudinal Healthy Longevity Survey (CLHLS) were analyzed. Sleep duration was classified as normal (7-8 h), short (<7 h), or long (≥9 h). Sensory impairment was assessed using individuals' self-reported data on visual and hearing functions. Cox regression was performed to evaluate the effects of sleep duration and altered sleep duration on sensory impairment, including visual impairment (VI) and hearing impairment (HI).

Results

This study included 3,578 older adults (mean age: 78.12 ± 9.59 years). Among them, 2,690 (75.2%) were aged 65-84 years and 1798 (50.3%) were women. The risks of VI (hazard ratio [HR]: 1.14; 95% confidence interval [CI]: 1.02-1.29), HI (HR: 1.14; 95% CI: 1.00-1.30), and dual sensory impairment (both VI and HI; HR: 1.26; 95% CI: 1.03-1.55) were high in older adults with long sleep duration. In addition, the risks of VI, HI, and dual sensory impairment were high in individuals whose sleep duration changed from normal to short or long (HR: 1.20 [95% CI: 1.02-1.42], 1.26 [95% CI: 1.03-1.53], and 1.54 [95% CI: 1.11-2.12], respectively) and those with persistently short or long sleep duration (HR: 1.25 [95% CI: 1.07-1.46], 1.34 [95% CI: 1.11-1.61], and 1.67 [95% CI: 1.22-2.27], respectively).

Conclusion

A prospective association was identified between altered sleep duration and sensory impairment in Chinese older adults. Our findings highlight the importance of optimal sleep duration and healthy sleep habits in preventing sensory impairment in older adults.

Daily Activity Lifelogs of People With Heart Failure: Observational Study

BACKGROUND

Globally, heart failure (HF) affects more than 64 million people, and attempts to reduce its social and economic burden are a public health priority. Interventions to support people with HF to self-manage have been shown to reduce hospitalizations, improve quality of life, and reduce mortality rates. Understanding how people self-manage is imperative to improve future interventions; however, most approaches to date, have used self-report methods to achieve this. Wearable cameras provide a unique tool to understand the lived experiences of people with HF and the daily activities they undertake, which could lead to more effective interventions. However, their potential for understanding chronic conditions such as HF is unclear.

OBJECTIVE

This study aimed to determine the potential utility of wearable cameras to better understand the activities of daily living in people living with HF.

METHODS

The "Seeing is Believing (SIB)" study involved 30 patients with HF who wore wearable cameras for a maximum of 30 days. We used the E-Myscéal web-based lifelog retrieval system to process and analyze the wearable camera image data set. Search terms for 7 daily activities (physical activity, gardening, shopping, screen time, drinking, eating, and medication intake) were developed and used for image retrieval. Sensitivity analysis was conducted to compare the number of images retrieved using different search terms. Temporal patterns in daily activities were examined, and differences before and after hospitalization were assessed.

RESULTS

E-Myscéal exhibited sensitivity to specific search terms, leading to significant variations in the number of images retrieved for each activity. The highest number of images returned were related to eating and drinking, with fewer images for physical activity, screen time, and taking medication. The majority of captured activities occurred before midday. Notably, temporal differences in daily activity patterns were observed for participants hospitalized during this study. The number of medication images increased after hospital discharge, while screen time images decreased.

CONCLUSIONS

Wearable cameras offer valuable insights into daily activities and self-management in people living with HF. E-Myscéal efficiently retrieves relevant images, but search term sensitivity underscores the need for careful selection.

Exposure to indoor light at night in relation to multiple dimensions of sleep health: findings from the Sister Study

STUDY OBJECTIVE

To examine the association between light at night (LAN) and multiple sleep health dimensions.

METHODS

Among 47 765 Sister Study participants, indoor LAN (TV on in the room, light(s) on in room, light from outside the room, nightlight, no light) and sleep dimensions were self-reported at baseline (2003-2009). We used Poisson regression with robust variance to estimate adjusted prevalence ratios (PR) and 95% confidence intervals (CI) for the cross-sectional associations between LAN and short sleep duration (<7 hours/night), insomnia symptoms (difficulty falling or staying asleep), frequent napping (≥3 naps/week), inconsistent sleep/wake time (differed day-to-day and week-to-week), sleep debt (≥2 hours between longest and shortest duration), recent sleep medication use, and a cumulative poor sleep score (≥3 poor sleep dimensions). Population-attributable risks (PARs) were determined for any light exposure vs. none by race/ethnicity.

RESULTS

Compared to sleeping with no light in the bedroom, sleeping with a TV on was associated with a higher prevalence of most dimensions of poor sleep (e.g. short sleep duration: PR = 1.38, 95% CI: 1.32 to 1.45; inconsistent sleep/wake time: PR = 1.55, 95% CI: 1.44 to 1.66; sleep debt: PR = 1.36, 95% CI: 1.29 to 1.44; poor sleep score: PR = 1.58, 95% CI: 1.48-1.68). PARs tended to be higher for non-Hispanic black women compared to non-Hispanic white women.

CONCLUSIONS

Sleeping with a TV on was associated with poor sleep health among US women, and non-Hispanic black women may be disproportionately burdened.

Age Differences in the Association of Sleep Duration Trajectory With Cancer Risk and Cancer-Specific Mortality: Prospective Cohort Study

BACKGROUND

Baseline sleep duration is associated with cancer risk and cancer-specific mortality; however, the association between longitudinal patterns of sleep duration and these risks remains unknown.

OBJECTIVE

This study aimed to elucidate the association between sleep duration trajectory and cancer risk and cancer-specific mortality.

METHODS

The participants recruited in this study were from the Kailuan cohort, with all participants aged between 18 and 98 years and without cancer at baseline. The sleep duration of participants was continuously recorded in 2006, 2008, and 2010. Latent mixture modeling was used to identify shared sleep duration trajectories. Furthermore, the Cox proportional risk model was used to examine the association of sleep duration trajectory with cancer risk and cancer-specific mortality.

RESULTS

A total of 53,273 participants were included in the present study, of whom 40,909 (76.79%) were men and 12,364 (23.21%) were women. The average age of the participants was 49.03 (SD 11.76) years. During a median follow-up of 10.99 (IQR 10.27-11.15) years, 2705 participants developed cancers. Three sleep duration trajectories were identified: normal-stable (44,844/53,273, 84.18%), median-stable (5877/53,273, 11.03%), and decreasing low-stable (2552/53,273, 4.79%). Compared with the normal-stable group, the decreasing low-stable group had increased cancer risk (hazard ratio [HR] 1.39, 95% CI 1.16-1.65) and cancer-specific mortality (HR 1.54, 95% CI 1.18-2.06). Dividing the participants by an age cutoff of 45 years revealed an increase in cancer risk (HR 1.88, 95% CI 1.30-2.71) and cancer-specific mortality (HR 2.52, 95% CI 1.22-5.19) only in participants younger than 45 years, rather than middle-aged or older participants. Joint analysis revealed that compared with participants who had a stable sleep duration within the normal range and did not snore, those with a shortened sleep duration and snoring had the highest cancer risk (HR 2.62, 95% CI 1.46-4.70).

CONCLUSIONS

Sleep duration trajectories and quality are closely associated with cancer risk and cancer-specific mortality. However, these associations differ with age and are more pronounced in individuals aged <45 years.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR-TNRC-11001489; http://tinyurl.com/2u89hrhx.

The context of COVID-19 affected the long-term sleep quality of older adults more than SARS-CoV-2 infection

Introduction

Sleep problems are one of the most persistent symptoms of post-COVID syndrome in adults. However, most recent research on sleep quality has relied on the impact of the pandemic, with scarcely any data for older adults on the long-term consequences of COVID infection. This study aims to understand whether older individuals present persistently impaired sleep quality after COVID-19 infection and possible moderators for this outcome.

Methods

This is a cross-sectional analysis of a longitudinal cohort study with 70 elders with 6-month-previous SARS-CoV-2 infection and 153 controls. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality; Geriatric Depression Scale and Geriatric Anxiety Inventory for screening depression and anxiety. Demographics and comorbid conditions were collected.

Results

The mean age of participants was 66,97 ± 4,64 years. There were no statistical differences in depression and anxiety between groups. Poor sleep quality was found in 52,9% and 43,8% of the COVID and control groups (p=.208). After controlling for multiple variables, all the following factors resulted in greater chances of poor sleep quality: female gender (OR, 2.12; p=.027), memory complaints (OR, 2.49; p=.074), insomnia (OR, 3.66; p=.032), anxiety (OR, 5.46; p<.001), depression (OR, 7.26; p=.001), joint disease (OR, 1.80; p=.050), glucose intolerance (OR, 2.20; p=.045), psychoactive drugs (OR, 8.36; p<.001), diuretics (OR, 2.46; p=.034), and polypharmacy (OR, 2.84; p=.016).

Conclusion

Psychosocial burden in the context of the COVID-19 pandemic and pre-existing conditions seems to influence the sleep quality of older adults more than SARS-CoV-2 infection.

Sleep duration, insomnia and cognitive performance in the Elsa-Brasil cohort: a cross-sectional analysis

OBJECTIVE

To investigate the single and combined associations between sleep disturbances (sleep duration, insomnia symptoms in the last 30 nights, and daytime tiredness) and performance in cognitive tests.

METHODS

Cross-sectional analysis of data from visit 2 (2012-2014) of the Longitudinal Study of Adult Health from a cohort of active and retired civil servants from six Brazilian capitals. Polynomial regression with quadratic term and multiple linear regression models were performed to assess single and combined associations between sleep disturbances and memory performance, fluency, executive functions, and global cognition.

RESULTS

A total of 7,248 participants were included, with a mean age of 62.7 years (standard deviation [SD]=5.9), and 55.2% were women. Inverted U-shaped associations were observed between sleep duration and performance on all cognitive abilities, suggesting that durations shorter or longer than seven hours are associated with worse performance, regardless of age. Reported insomnia was associated with worse executive function (β: -0.08; 95% confidence interval [CI]: -0.15 to -0.01), and the magnitudes of associations were higher for individuals with insomnia at two or more moments (β: -0.12; 95%CI -0.19 to -0.05) or, especially, insomnia combined with short sleep (β: -0.18; 95%CI -0.24 to -0.11). Insomnia in two or more periods was also associated with lower memory and global cognition. There was no association between any sleep disturbance tested and verbal fluency. Isolated daytime tiredness was not associated with performance in the evaluated tests.

CONCLUSION

The results suggest that extreme sleep durations are detrimental to almost all cognitive abilities investigated, whereas insomnia appears to affect more severely the executive function.

The relationship between social support and sleep quality in older adults: A review of the evidence

OBJECTIVES

Sleep quality is crucial for the health and well-being of older adults, and social support has been consistently shown to be related to sleep quality. However, there is a need for research to understand the mechanisms through which these two factors are linked. The purpose of this review is to synthesize scientific literature on the relationship between social support and sleep quality in older adults.

METHODS

Using an integrative review method, this review was conducted for a period from January 2012 to November 2022 using a combination of keywords related to social support and sleep quality in older adults.

RESULTS

A total of 21 studies that met the inclusion criteria were included. Social support was found to have a positive relationship with subjective and objective sleep quality. It may act as both a mediator between insomnia and hopelessness and a moderator buffering the influence of rumination and negative emotions on sleep quality.

CONCLUSION

This review provides evidence for the positive relationship between social support and sleep quality in older adults. Based on the findings of this review, healthcare professionals should prioritize incorporating assessments of social support and implementing interventions aimed at enhancing social support in older adults to improve their sleep quality.

Who sleeps well in Canada? The social determinants of sleep health among middle-aged and older adults in the Canadian Longitudinal Study on Aging

OBJECTIVES

Sleep health inequities likely contribute to disparities in health outcomes. Our objective was to identify social determinants of sleep health among middle-aged/older adults in Canada, where prior evidence is limited.

METHODS

We analyzed cross-sectional data from the Canadian Longitudinal Study on Aging, a survey of over 30,000 community-dwelling adults aged 45-85years. Self-reported measures included sleep duration, sleep satisfaction, and sleep efficiency. We explored associations between sleep measures and social determinants of health. We used modified Poisson regression to estimate prevalence ratios for sleep satisfaction and sleep efficiency, and linear regression for sleep duration. Estimates were adjusted for all social, lifestyle, and clinical covariates. We explored effect modification by sex.

RESULTS

Of the 11 social determinants explored, all were significantly associated with at least one domain of sleep health. These associations were reduced to 9 variables with adjustment for all social variables, and 7 with further adjustment for lifestyle and clinical covariates, including differences by sex, age, education, marital status, employment, race/ethnicity, and sexual orientation. Better sleep health in >1 domain was observed among males, older age groups (65 and older), higher income groups, the retired group, and homeowners with adjustment for social variables, and only in males and older age groups with additional adjustment for lifestyle and clinical variables. Only sleep duration associations were modified by sex.

CONCLUSIONS

Sleep health disparities among Canadian adults exist across socioeconomic gradients and racial/ethnic minority groups. Poor sleep health among disadvantaged groups warrants increased attention as a public health problem in Canada.

The effects of partial sleep restriction and subsequent caffeine ingestion on neurovascular coupling

Habitual poor sleep is associated with cerebrovascular disease. Acute sleep deprivation alters the ability to match brain blood flow to metabolism (neurovascular coupling [NVC]) but it is not known how partial sleep restriction affects NVC. When rested, caffeine disrupts NVC, but its effects in the sleep-restricted state are unknown. The purpose of this study was therefore to investigate the effects of partial sleep restriction and subsequent caffeine ingestion on NVC. A total of 17 adults (mean [standard deviation] age 27 [5] years, nine females) completed three separate overnight conditions with morning supplementation: habitual sleep plus placebo (Norm_Pl), habitual sleep plus caffeine (Norm_Caf), and partial (50% habitual sleep) restriction plus caffeine (PSR_Caf). NVC responses were quantified as blood velocity through the posterior (PCAv) and middle (MCAv) cerebral arteries using transcranial Doppler ultrasound during a visual search task and cognitive function tests, respectively. NVC was assessed the evening before and twice the morning after each sleep condition-before and 1-h after caffeine ingestion. NVC responses as a percentage increase in PCAv and MCAv from resting baseline were not different at any timepoint, across all conditions (p > 0.053). MCAv at baseline, and PCAv at baseline, peak, and total area under the curve were lower 1-h after caffeine in both Norm_Caf and PSR_Caf as compared to Norm_Pl (p < 0.05), with no difference between Norm_Caf and PSR_Caf (p > 0.14). In conclusion, NVC was unaltered after 50% sleep loss, and caffeine did not modify the magnitude of the response in the rested or sleep-deprived state. Future research should explore how habitual poor sleep affects cerebrovascular function.

Associations of sleep duration and daytime sleepiness with plasma amyloid beta and cognitive performance in cognitively unimpaired, middle-aged and older African Americans

STUDY OBJECTIVES

Given the established racial disparities in both sleep health and dementia risk for African American populations, we assess cross-sectional and longitudinal associations of self-report sleep duration (SRSD) and daytime sleepiness with plasma amyloid beta (Aβ) and cognition in an African American (AA) cohort.

METHODS

In a cognitively unimpaired sample drawn from the African Americans Fighting Alzheimer's in Midlife (AA-FAiM) study, data on SRSD, Epworth Sleepiness Scale, demographics, and cognitive performance were analyzed. Aβ40, Aβ42, and the Aβ42/40 ratio were quantified from plasma samples. Cross-sectional analyses explored associations between baseline predictors and outcome measures. Linear mixed-effect regression models estimated associations of SRSD and daytime sleepiness with plasma Aβ and cognitive performance levels and change over time.

RESULTS

One hundred and forty-seven participants comprised the cross-sectional sample. Baseline age was 63.2 ± 8.51 years. 69.6% self-identified as female. SRSD was 6.4 ± 1.1 hours and 22.4% reported excessive daytime sleepiness. The longitudinal dataset included 57 participants. In fully adjusted models, neither SRSD nor daytime sleepiness is associated with cross-sectional or longitudinal Aβ. Associations with level and trajectory of cognitive test performance varied by measure of sleep health.

CONCLUSIONS

SRSD was below National Sleep Foundation recommendations and daytime sleepiness was prevalent in this cohort. In the absence of observed associations with plasma Aβ, poorer self-reported sleep health broadly predicted poorer cognitive function but not accelerated decline. Future research is necessary to understand and address modifiable sleep mechanisms as they relate to cognitive aging in AA at disproportionate risk for dementia.

CLINICAL TRIAL INFORMATION

Not applicable.

Salivary Interleukin 1-Beta Concentration Associates With Sleep Quality in Older Individuals

Background: Poor sleep quality is prevalent in older people and impairs their quality of life. Various studies show an association between sleep disorders and altered levels of inflammatory cytokines. The cytokine IL-1β has been shown to display both somnogenic and insomnia-promoting effects in experimental animals. Objectives: to evaluate the relationship between insomnia and salivary IL-1β concentration and the role of associated factors such as the symptoms of depression, use of hypnotics, intake of caffeinated beverages, smoking, and alcohol use in older individuals. An analytical, cross-sectional, observational research was carried out with a population of community-dwelling individuals over 60 years of age in Valencia (Spain). Sleep quality was measured with the Athens insomnia scale (AIS) and depressive symptoms with Geriatric Depression Scale (GDS). Results: 287 individuals participated in the study (mean age 74.08 years (76.7% women). 41.5% of the participants had insomnia, 36.9% took drugs for sleep problems, and 32.4% had relevant depressive symptoms. There was a significant inverse correlation between the IL-1β and total AIS score (rho = -0.302, p < 0.001), the sleep difficulty subdomain (rho = -0.259, p < 0.001), and the daytime sleepiness subdomain (rho = -0.322, p < 0.001). No significant correlation was observed between GDS and salivary IL-1β concentration. The IL-1β concentration was significantly lower in individuals taking drugs for sleeping compared with those not taking those drugs (1.11 ± 0.09 and 1.48 ± 0.08, respectively; p = 0.001). Regarding the AIS score, there was no significant difference in marital status, smoking, or the number of cups of tea or cola drinks, but there was a significant association with alcohol intake (p = 0.019) and in the number of daily intakes of coffee (p = 0.030). The receiver operating characteristic (ROC) curve analysis of IL-1β for diagnosis of moderate-severe insomnia showed an area under the curve (AUC) value of 0.78 (95% confidence interval 0.71-0.85). At the cut-off of 0.83 pg/µL of Il-1β, it had a sensitivity of 70.3% and a specificity of 69.8%.

Evolution of Sleep Complaints in Myotonic Dystrophy Type 1: A 9-Year Longitudinal Study

The objective was to characterize the progression of sleep complaints in 115 dystrophy type 1 (DM1) patients who filled out a sleep questionnaire twice at a 9-year interval. Daytime napping (22.1% vs. 34.5%, p < 0.05), early awakenings (11.4% vs 21.1%, p < 0.05), nonrestorative sleep (39.5% vs 51.8%, p < 0.05), stimulant use (7.0% vs 19.3%, p < 0.01), breathing cessation (10.7% vs 23.2%, p < 0.01), and nighttime urination (42.5% vs 54.9%, p < 0.05) increased between Time 1 and Time 2. Sleep-related complaints are prominent and augment rapidly in DM1 patients. Physicians need to better identify and treat them to help alleviate the burden they impose on patients and their caregivers.

Effectiveness of High-dose Clonazepam Versus Low-Dose Clonazepam With Cognitive Behavioral Therapy in Older Adults With Moderately Severe Insomnia: A Prospective Cohort Study

PURPOSE

To evaluate the effectiveness of high-dose clonazepam (1 mg) versus low-dose clonazepam (0.5 mg) with cognitive behavioral therapy for insomnia (CBT-i) in older adults with moderately severe insomnia.

METHODS

A prospective cohort study was conducted in patients who did not respond to low-dose clonazepam for insomnia secondary to chronic medical conditions. After starting with 0.25 mg of clonazepam, their dose was increased to 0.5 mg, then to 1 mg (Group A), or to the same dose with additional CBT-i (Group B). They were followed for 24 weeks, and scores of the insomnia severity index (ISI) and subjective units of distress scale (SUDS) were recorded. Patient adverse drug reactions (ADRs) were documented and assessed for their causality. ISI and SUDS scores were considered primary outcome measures.

FINDINGS

Between-group analysis revealed a significant decline in the mean score of ISI at week 16 (P < 0.05) and for SUDS at week 20 (P < 0.05) in group B compared to group A. Similarly, within-group analysis also revealed a statistically significant reduction of the mean score in ISI and SUDS scores at week 4 and 8 (P < 0.05) in both groups. ADRs occurred more frequently in group A (14%) than in group B (5%). Assessments of causality showed that the majority of cases were possible.

IMPLICATIONS

For individuals who were resistant to 0.5 mg of clonazepam, adding CBT-i with low-dose clonazepam is a viable alternative to increasing the dose to 1 mg.

Predicting neurodegeneration from sleep related biofluid changes

Sleep-wake disturbances are common in neurodegenerative diseases and may occur years before the clinical diagnosis, potentially either representing an early stage of the disease itself or acting as a pathophysiological driver. Therefore, discovering biomarkers that identify individuals with sleep-wake disturbances who are at risk of developing neurodegenerative diseases will allow early diagnosis and intervention. Given the association between sleep and neurodegeneration, the most frequently analyzed fluid biomarkers in people with sleep-wake disturbances to date include those directly associated with neurodegeneration itself, such as neurofilament light chain, phosphorylated tau, amyloid-beta and alpha-synuclein. Abnormalities in these biomarkers in patients with sleep-wake disturbances are considered as evidence of an underlying neurodegenerative process. Levels of hormonal sleep-related biomarkers such as melatonin, cortisol and orexin are often abnormal in patients with clinical neurodegenerative diseases, but their relationships with the more standard neurodegenerative biomarkers remain unclear. Similarly, it is unclear whether other chronobiological/circadian biomarkers, such as disrupted clock gene expression, are causal factors or a consequence of neurodegeneration. Current data would suggest that a combination of fluid biomarkers may identify sleep-wake disturbances that are most predictive for the risk of developing neurodegenerative disease with more optimal sensitivity and specificity.

Mediterranean Diet and Cardiovascular Disease: The Moderating Role of Adequate Sleep-Results from the ATTICA Cohort Study (2002-2022)

The relationship between diet, sleep duration and cardiovascular disease (CVD) has not been well understood. The aim of the present study was to test the potential modifying role of sleep duration in the association between adherence to the Mediterranean-type diet (MD) and CVD risk. The study consisted of n = 313 initially free-of-CVD adults, from the ATTICA cohort study (2002-2022), with available information on sleep habits. Sleep habits were categorized as inadequate and adequate sleep duration (< or ≥7 h/day, respectively). In multi-adjusted analysis, MD adherence was inversely associated with CVD risk [Hazard Ratio-HR per 1/55 in MedDietScore: 0.80, 95% Confidence Interval-CI: 0.65, 0.98]. A significant interaction between sleep duration and MedDietScore was observed (p < 0.001). In subgroup analysis, the protective association between MD adherence and CVD risk was found only in participants who slept adequately, i.e., >7 h/day [HR:0.80, 95%CI: 0.65, 0.98]. Those who had a high adherence to the MD along with adequate sleep habits, had a 70% reduced 20-year CVD risk [HR:0.30, 95%CI: 0.11, 0.80], compared to those who had a low MD adherence and inadequate sleep habits. Sleep duration should be a part of an individual's lifestyle, together with dietary and other habits, to effectively evaluate CVD risk for future events.

Association between sleep duration and antibody acquisition after mRNA vaccination against SARS-CoV-2

Introduction

Sleep enhances the antibody response to vaccination, but the relationship between sleep and mRNA vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is not fully understood.

Methods

In this prospective observational study, we investigated the influence of sleep habits on immune acquisition induced by mRNA vaccines against SARS-CoV-2 in 48 healthy adults (BNT-162b2, n=34; mRNA-1273, n=14; female, n=30, 62.5%; male, n=18, 37.5%; median age, 39.5 years; interquartile range, 33.0-44.0 years) from June 2021 to January 2022. The study measured sleep duration using actigraphy and sleep diaries, which covered the periods of the initial and booster vaccinations.

Results

Multivariable linear regression analysis showed that actigraphy-measured objective sleep duration 3 and 7 days after the booster vaccination was independently and significantly correlated with higher antibody titers (B=0.003; 95% confidence interval, 0.000-0.005; Beta=0.337; p=0.02), even after controlling for covariates, including age, sex, the type of vaccine, and reactogenicity to the vaccination. Associations between acquired antibody titer and average objective sleep duration before vaccination, and any period of subjective sleep duration measured by sleep diary were negligible.

Discussion

Longer objective, but not subjective, sleep duration after booster vaccination enhances antibody response. Hence, encouraging citizens to sleep longer after mRNA vaccination, especially after a booster dose, may increase protection against SARS-CoV-2.

Study registration

This study is registered at the University Hospital Medical Information Network Center (UMIN: https://www.umin.ac.jp) on July 30, 2021, #UMIN000045009.

Longitudinal Sleep Patterns and Cognitive Impairment in Older Adults

Importance

Sleep disturbances and clinical sleep disorders are associated with all-cause dementia and neurodegenerative conditions, but it remains unclear how longitudinal changes in sleep impact the incidence of cognitive impairment.

Objective

To evaluate the association of longitudinal sleep patterns with age-related changes in cognitive function in healthy older adults.

Design, Setting, and Participants

This cross-sectional study is a retrospective longitudinal analyses of the Seattle Longitudinal Study (SLS), which evaluated self-reported sleep duration (1993-2012) and cognitive performance (1997-2020) in older adults. Participants within the SLS were enrolled as part of a community-based cohort from the Group Health Cooperative of Puget Sound and Health Maintenance Organization of Washington between 1956 and 2020. Data analysis was performed from September 2020 to May 2023.

Main Outcomes and Measures

The main outcome for this study was cognitive impairment, as defined by subthreshold performance on both the Mini-Mental State Examination and the Mattis Dementia Rating Scale. Sleep duration was defined by self-report of median nightly sleep duration over the last week and was assessed longitudinally over multiple time points. Median sleep duration, sleep phenotype (short sleep, median ≤7 hours; medium sleep, median = 7 hour; long sleep, median ≥7 hours), change in sleep duration (slope), and variability in sleep duration (SD of median sleep duration, or sleep variability) were evaluated.

Results

Of the participants enrolled in SLS, only 1104 participants who were administered both the Health Behavior Questionnaire and the neuropsychologic battery were included for analysis in this study. A total of 826 individuals (mean [SD] age, 76.3 [11.8] years; 468 women [56.7%]; 217 apolipoprotein E ε4 allele carriers [26.3%]) had complete demographic information and were included in the study. Analysis using a Cox proportional hazard regression model (concordance, 0.76) showed that status as a short sleeper (hazard ratio, 3.67; 95% CI, 1.59-8.50) and higher sleep variability (hazard ratio, 3.06; 95% CI, 1.14-5.49) were significantly associated with the incidence of cognitive impairment.

Conclusions and Relevance

In this community-based longitudinal study of the association between sleep patterns and cognitive performance, the short sleep phenotype was significantly associated with impaired cognitive performance. Furthermore, high sleep variability in longitudinal sleep duration was significantly associated with the incidence of cognitive impairment, highlighting the possibility that instability in sleep duration over long periods of time may impact cognitive decline in older adults.

Epidemiology of insomnia disorder in older persons according to the Diagnostic and Statistical Manual of Mental Disorders: a systematic review and meta-analysis

PURPOSE

There is a scarcity of summarizing data on the epidemiology of insomnia in older persons, especially when diagnosed with international criteria. This study aimed to estimate the prevalence and correlates of insomnia disorder in older persons, according to the Diagnostic and Statistical Manual of Mental Disorders (DSM).

METHODS

Through PubMed/MEDLINE, EMBASE, and Web of Science (WoS), we searched for relevant articles published before June 28, 2023. The risk of bias was weighed using the Joanna Briggs Institute's (JBI's) critical appraisal checklist for studies reporting prevalence data. For our analyses, we used a random-effect model, with subgroup analyses, meta-regression, and sensitivity analyses to explore potential sources of heterogeneity. We followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement.

RESULTS

We included 18,270 participants across 16 studies. The male/female ratio was 0.89 (12 studies), and the mean age varied from 65.9 to 83.1 years (8 studies). The pooled prevalence of insomnia was 19.6% (95% CI = [12.3%; 28.3%]), with substantial heterogeneity. This prevalence fluctuated according to the sample size, the minimal age for inclusion, and the study quality, considering that the risk of bias was moderate for most of studies. There was a publication bias, with a very low level of certainty. Insomnia disorder was associated with the female gender, depression, anxiety, and somatic illnesses notably cardiovascular, respiratory, and painful ones.

CONCLUSION

Nearly one in every five old individuals was considered to have insomnia disorder, which was associated with the gender and the existence of mental health and/or somatic conditions.

REGISTRATION

We registered the protocol in the International Prospective Register of Systematic Reviews (PROSPERO) with registration number: CRD42022344675.

CPAP adherence after ambulatory and in-hospital management in patients aged 65 years and older

OBJECTIVES

The aims of this study are to evaluate the early adherence to CPAP treatment in patients aged 65 years and older and to compare ambulatory (ACPAP) and in-hospital (HCPAP) management in starting CPAP treatment.

METHODS

Adherence to CPAP therapy at 3 months was retrospectively studied in patients on whom CPAP therapy was initiated between 1 January 2020 and 31 December 2021. Patients in the ACPAP group were selected based on the current Belgian reimbursement criteria (OAHI ≥30/h and few comorbidities).

RESULTS

146 patients were studied (median OAHI 43.35/h [32.02; 57.40]; median age 69 [67.0; 73.0]): 116 (79.5%) patients in the HCPAP and 30 (20.5%) in the ACPAP group. Based on an adherence threshold of average CPAP use of ≥ 4 hours per day, 120 (82%) patients were adherent to the treatment; 94 (81%) patients in the HCPAP and 26 (86.7%) in the ACPAP group. The median CPAP use for the total population was 6.4 h/day [4.89; 7.34], reaching 6.3 h/d [4.79; 7.15] for the HCPAP group and 6.8 h/d [6.21; 8.06] for the ACPAP group (p = 0.019). Insomnia was a significant risk factor for non-adherence (OR 5.16 [1.64; 16.08], p = 0.0043) but the ACPAP method was not (OR 0.66 [0.18; 1.91], p = 0.4748).

CONCLUSION

Early CPAP adherence in patients ≥ 65 years old was good in terms of average use per day and proportion of adherent patients. ACPAP method was not a risk factor for lower CPAP adherence in patients presenting severe OSAS (OAHI ≥30/h) and few comorbidities.

The association between sleep duration and muscle sympathetic nerve activity

PURPOSE

Sleep duration is associated with risk of hypertension and cardiovascular diseases. It is thought that shorter sleep increases sympathetic activity. However, most studies are based on acute experimental sleep deprivation that have produced conflicting results. Furthermore, there are limited data available on habitual sleep duration and gold-standard measures of sympathetic activation. Hence, this study aimed to assess the association between habitual sleep duration and muscle sympathetic nerve activity.

METHODS

Twenty-four participants aged ≥ 18 years were included in the study. Sleep was assessed using at-home 7-day/night actigraphy (ActiGraph™ GT3X-BT) and sleep questionnaires (Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale). Microelectrode recordings of muscle sympathetic nerve activity were obtained from the common peroneal nerve. Participants were categorised into shorter or longer sleep duration groups using a median split of self-report and actigraphy sleep measures.

RESULTS

Compared to longer sleepers, shorter sleepers averaged 99 ± 40 min and 82 ± 40 min less sleep per night as assessed by self-report and objective measures, respectively. There were no differences in age (38 ± 18 vs 39 ± 21 years), sex (5 male, 7 female vs 6 male, 6 female), or body mass index (23 ± 3 vs 22 ± 3 kg/m2) between shorter and longer sleepers. Expressed as burst frequency, muscle sympathetic nerve activity was higher in shorter versus longer sleepers for both self-report (39.4 ± 12.9 vs 28.4 ± 8.5 bursts/min, p = 0.019) and objective (37.9 ± 12.4 vs 28.1 ± 8.8 bursts/min, p = 0.036) sleep duration.

CONCLUSIONS

Shorter sleep duration assessed in a home setting was associated with higher muscle sympathetic nerve activity. Sympathetic overactivity may underlie the association between short sleep and hypertension.

Pilot feasibility and acceptability study evaluating use of group CBT-I in improving sleep and fatigue in older adults

OBJECTIVE

This paper describes a pilot study, in a small sample of older adults, designed to ascertain the feasibility, acceptability and potential effectiveness of group Cognitive Behavioural Therapy For Insomnia (CBT-I).

METHODS

Eleven older adults participated in a 3-week group CBT-I intervention with pre- and post-intervention outcome measures of sleep and fatigue. Acceptability was measured via post-intervention focus groups. Feasibility was measured via recruitment, retention and completion data. Subjective sleep outcomes were measured pre- and post-intervention using the Pittsburgh Sleep Quality Index. Fatigue was measured using the Fatigue Severity Index. Objective sleep outcome measures were obtained via pre- and post-intervention wrist actigraphy.

RESULTS

Feasibility and acceptability were confirmed in the pilot study. Retention and completion levels were high, with participants largely positive in the focus group feedback. Preliminary sleep outcome data supported the potential effectiveness of the intervention in significantly improving several measures of sleep and fatigue including a three-point reduction in the Global PSQI scores, an increase in total sleep time of almost an hour per night and these results were mirrored by a significant reduction of nine points in the overall measure of fatigue severity.

CONCLUSIONS

A group CBT-I intervention is a low-cost, low-risk intervention which improves subjective and objective measures of sleep in older adults. These positive sleep outcomes are translated into significantly decreased levels of fatigue. Future research should focus on a larger sample size with a randomised controlled trial design.

Cortical Synchrony and Information Flow during Transition from Wakefulness to Light Non-Rapid Eye Movement Sleep

Sleep is a highly stereotyped phenomenon, requiring robust spatiotemporal coordination of neural activity. Understanding how the brain coordinates neural activity with sleep onset can provide insights into the physiological functions subserved by sleep and the pathologic phenomena associated with sleep onset. We quantified whole-brain network changes in synchrony and information flow during the transition from wakefulness to light non-rapid eye movement (NREM) sleep, using MEG imaging in a convenient sample of 14 healthy human participants (11 female; mean 63.4 years [SD 11.8 years]). We furthermore performed computational modeling to infer excitatory and inhibitory properties of local neural activity. The transition from wakefulness to light NREM was identified to be encoded in spatially and temporally specific patterns of long-range synchrony. Within the delta band, there was a global increase in connectivity from wakefulness to light NREM, which was highest in frontoparietal regions. Within the theta band, there was an increase in connectivity in fronto-parieto-occipital regions and a decrease in temporal regions from wakefulness to Stage 1 sleep. Patterns of information flow revealed that mesial frontal regions receive hierarchically organized inputs from broad cortical regions upon sleep onset, including direct inflow from occipital regions and indirect inflow via parieto-temporal regions within the delta frequency band. Finally, biophysical neural mass modeling demonstrated changes in the anterior-to-posterior distribution of cortical excitation-to-inhibition with increased excitation-to-inhibition model parameters in anterior regions in light NREM compared with wakefulness. Together, these findings uncover whole-brain corticocortical structure and the orchestration of local and long-range, frequency-specific cortical interactions in the sleep-wake transition.SIGNIFICANCE STATEMENT Our work uncovers spatiotemporal cortical structure of neural synchrony and information flow upon the transition from wakefulness to light non-rapid eye movement sleep. Mesial frontal regions were identified to receive hierarchically organized inputs from broad cortical regions, including both direct inputs from occipital regions and indirect inputs via the parieto-temporal regions within the delta frequency range. Biophysical neural mass modeling revealed a spatially heterogeneous, anterior-posterior distribution of cortical excitation-to-inhibition. Our findings shed light on the orchestration of local and long-range cortical neural structure that is fundamental to sleep onset, and support an emerging view of cortically driven regulation of sleep homeostasis.

In vivo marker of brainstem myelin is associated to quantitative sleep parameters in healthy young men

The regional integrity of brain subcortical structures has been implicated in sleep-wake regulation, however, their associations with sleep parameters remain largely unexplored. Here, we assessed association between quantitative Magnetic Resonance Imaging (qMRI)-derived marker of the myelin content of the brainstem and the variability in the sleep electrophysiology in a large sample of 18-to-31 years healthy young men (N = 321; ~ 22 years). Separate Generalized Additive Model for Location, Scale and Shape (GAMLSS) revealed that sleep onset latency and slow wave energy were significantly associated with MTsat estimates in the brainstem (pcorrected ≤ 0.03), with overall higher MTsat value associated with values reflecting better sleep quality. The association changed with age, however (MTsat-by-age interaction-pcorrected ≤ 0.03), with higher MTsat value linked to better values in the two sleep metrics in the younger individuals of our sample aged ~ 18 to 20 years. Similar associations were detected across different parts of the brainstem (pcorrected ≤ 0.03), suggesting that the overall maturation and integrity of the brainstem was associated with both sleep metrics. Our results suggest that myelination of the brainstem nuclei essential to regulation of sleep is associated with inter-individual differences in sleep characteristics during early adulthood. They may have implications for sleep disorders or neurological diseases related to myelin.