Follow-up of children with Down syndrome and sleep disordered breathing and the effects of treatment on actigraphically recorded sleep, quality of life, behaviour, and daytime functioning.

Children with Down syndrome are at increased risk of obstructive sleep disordered breathing, which has deleterious effects on daytime functioning. We aimed to examine the effects of treatment of sleep disordered breathing on sleep quality and daytime functioning in children with Down syndrome, and hypothesised that these would be improved. Thirty-four children completed a baseline study and a follow-up 2 years later. Measures at both time points included 7 days of actigraphy and parents completed a number of questionnaires assessing sleep, behaviour, daytime functioning, and quality of life. All children had overnight polysomnography at baseline; 15 children (44%) were treated. At baseline the treated group had more severe sleep disordered breathing compared with the untreated group: obstructive apneoa-hypopnoea index 29.3 ± 38.2 events/h versus 3.3 ± 5.2 events/h (p < 0.01). Actigraphy showed no significant differences in total sleep time, sleep efficiency, sleep schedules from baseline to follow up in either group. The sleep disturbance (p < 0.01) and total problems (p < 0.05) scales on the OSA-18 and the sleep disordered breathing subscale on the Paediatric Sleep Problem Survey Instrument (p < 0.01) improved in the treated children. There were no changes in any measure in the untreated children. Treatment of sleep disordered breathing improves symptoms, sleep disturbance and quality of life in children with Down syndrome, but has no demonstrable impact on actigraphic sleep measures or daytime behaviour or function. In contrast, children who were not treated, despite having less severe disease at baseline, had increased sleep disruption and no change in quality of life.

High sleep fragmentation parallels poor subjective sleep quality during the third wave of the Covid-19 pandemic: An actigraphic study.

Studies on sleep during the Covid-19 pandemic have mostly been conducted during the first wave of contagion (spring 2020). To follow up on two Italian studies addressing subjective sleep features during the second wave (autumn 2020), here we assess sleep during the third wave (spring 2021) in a sample of healthy adults from Campania (Southern Italy). Actigraphic data (on 2 nights) and the Pittsburgh Sleep Quality Index were collected from 82 participants (40 F, mean age: 32.5 ± 11.5 years) from 11 March to 18 April 2021, when Campania was classified as a "red zone", i.e. it was subjected to strict restrictions, only slightly looser than those characterizing the first national lockdown (spring 2020). Although objective sleep duration and architecture appeared in the normal range, the presence of disrupted sleep was indexed by a relevant degree of sleep fragmentation (number of awakenings ≥ 1 min: 12.7 ± 6.12; number of awakenings ≥ 5 min: 3.04 ± 1.52), paralleled by poor subjective sleep quality (Pittsburgh Sleep Quality Index global score: 5.77 ± 2.58). These data suggest that the relevant subjective sleep impairments reported during the first wave could have relied on subtle sleep disruptions that were undetected by the few objective sleep studies from the same period. Taken together with sleep data on previous phases of the pandemic, our findings show that the detrimental effects on sleep determined by the initial pandemic outbreak have not abated across the subsequent waves of contagion, and highlight the need for interventions addressing sleep health in global emergencies.

When to sleep and consume caffeine to boost alertness.

STUDY OBJECTIVES: Sleep loss can cause cognitive impairments that increase the risk of mistakes and accidents. However, existing guidelines to counteract the effects of sleep loss are generic and are not designed to address individual-specific conditions, leading to suboptimal alertness levels. Here, we developed an optimization algorithm that automatically identifies sleep schedules and caffeine-dosing strategies to minimize alertness impairment due to sleep loss for desired times of the day. METHODS: We combined our previous algorithms that separately optimize sleep or caffeine to simultaneously identify the best sleep schedules and caffeine doses that minimize alertness impairment at desired times. The optimization algorithm uses the predictions of the well-validated Unified Model of Performance to estimate the effectiveness and physiological feasibility of a large number of possible solutions and identify the best one. To assess the optimization algorithm, we used it to identify the best sleep schedules and caffeine-dosing strategies for four studies that exemplify common sleep-loss conditions and compared the predicted alertness-impairment reduction achieved by using the algorithm's recommendations against that achieved by following the U.S. Army caffeine guidelines. RESULTS: Compared to the alertness-impairment levels in the original studies, the algorithm's recommendations reduced alertness impairment on average by 63%, an improvement of 24 percentage points over the U.S. Army caffeine guidelines. CONCLUSIONS: We provide an optimization algorithm that simultaneously identifies effective and safe sleep schedules and caffeine-dosing strategies to minimize alertness impairment at user-specified times.

Impacts of COVID-19 Pandemic on Sleep Quality Evaluated by Wrist Actigraphy: A Systematic Review.

COVID-19 has probably contributed as a risk factor for sleep disturbance. Actigraphy has been used to evaluate sleep complaints in self-isolated populations and frontline doctors during the COVID-19 pandemic. This systematic review aims to summarize the impact of the COVID-19 pandemic on sleep through wrist actigraphy, estimating sleep latency, total sleep time, awakening-after-sleep onset, and sleep efficiency. Searches were conducted of observational studies on the PubMed, Embase, Scopus, Web of Science, and PEDro databases from 1 December 2019 to 31 December 2022. Ninety articles were found, and given the eligibility criteria, fifteen were selected. Six studies were classified by the National Health and Medical Research Council as evidence level IV, two studies as level III-3, and seven studies as level III-2. According to the ACROBAT-NRSI instrument, three studies were classified as having a "serious" risk of bias, two as having "critical" risk, four as having "moderate" risk, and six as having "low" risk. In the selected publications, various populations were evaluated via actigraphy during the COVID-19 pandemic, with reports of "poor" sleep quality. Actigraphy may be a relevant tool to assess individual day-night rhythms and provide recommendations under enduring pandemic conditions. Moreover, as actigraphy presents objective data for sleep evaluations, it is suggested that this method be used in similar pandemics and that actigraphy be included as part of the sleep hygiene strategy.

On workdays, earlier sleep for morningness and later wakeup for eveningness are associated with better work productivity.

INTRODUCTION: Misalignment of chronotype and social schedules result in sleep and health impairments. Presenteeism, the work productivity loss caused by health problems, has much more social costs than absenteeism and is associated with sleep disturbance. However, little is known about the link between chronotype and presenteeism. In this study, the associations between chronotype, sleep schedules, presenteeism, and the mediating role of sleep disturbance were examined. METHODS: A cross-sectional survey was conducted on 8155 office workers from 42 companies in Japan, from 2017 to 2019. The participants answered self-administered questionnaires asking about presenteeism (Work Limitations Questionnaire [WLQ]), sleep disturbance (Pittsburgh Sleep Quality Index [PSQI]), and habitual sleep schedules which enable to calculate the midpoint of sleep on free days, sleep corrected (MSFsc). The mediating effect was examined by using structural equation modeling (SEM). RESULTS: The participants comprised 4462 males and 3677 females (mean age: 36.7 years), and their mean productivity loss was 5.97%. A later sleep onset (+0.29%/h), early wakeup (+0.14%/h), and eveningness (+0.27%/h, MSFsc) were associated with presenteeism in all participants; however, the effect size and significance differed depending on their chronotype. SEM demonstrated a complete mediation model between chronotype and presenteeism, mediated by sleep disturbance and adjusted by age. CONCLUSIONS: Chronotype did not directly, but indirectly affected presenteeism through sleep disturbance. Eveningness leads to sleep disturbance, which then causes presenteeism. On workdays, early sleep times for morningness people, and late wakeup times for eveningness people may improve their work productivity.

Dissociated profiles of sleep timing and sleep quality changes across the first and second wave of the COVID-19 pandemic.

Previous work showed a significant impact of the COVID-19 pandemic on Italians' sleep both during the first wave, when a total lockdown (TL) was imposed, and during the second wave, when a partial lockdown (PL) was mandated (autumn 2020). Here we complement these data by describing the profile of sleep across four time-points: the first and second lockdown (TL, PL) and the months preceding them (pre-TL, pre-PL). An online survey was completed by 214 participants (Mage = 36.78 ± 14.2 y; 159 F) during TL and again during PL. All sleep-related questions (including items of the Pittsburgh Sleep Quality Index) required a double answer, one referred to the current lockdown and one to the month preceding the lockdown. Bedtime and rise time were delayed in TL and then advanced in pre-PL and PL. Similarly, time in bed increased in TL and then decreased in pre-PL and PL. Sleep quality worsened in the two lockdowns compared to the preceding periods and the proportion of poor sleepers correspondingly increased in both lockdowns. Sleep habits and quality displayed different profiles across phases of the pandemic. Sleep timing was altered during the first lockdown and then returned towards baseline (likely due to normalized working schedules). Instead, sleep quality, which markedly worsened during both lockdowns, appears particularly sensitive to changes in life habits and psychological factors, independently of sleep habits. Our findings also point to a possible role of acute and chronic stress (experienced during the first and second wave, respectively) in modulating sleep changes across the pandemic waves.

The Effects of the COVID19-Related Lockdown Are Modulated by Age: An Italian Study in Toddlers and Pre-Schoolers.

Although the issue has been repeatedly explored, data on the impact of the COVID-19 pandemic on children's sleep quality are inconsistent. To clarify these discrepancies, here we investigate possible age-related differences. During the lockdown, 112 parents of toddlers (0-3 years, N = 61) and pre-schoolers (4-5 years, n = 51) completed an online survey including the Children's Sleep Habits Questionnaire (CSHQ). Sleep-related items required an additional retrospective judgment, referring to the pre-pandemic period. During the lockdown, sleep schedules were delayed in both age groups whereas sleep quality (CSHQ total scores) improved in pre-schoolers but not in toddlers. Between-groups comparisons revealed that, prior to the lockdown, pre-schoolers showed worse sleep quality than toddlers, whereas this difference disappeared during home confinement. Also, pre-schoolers' sleep timing was advanced before the lockdown and delayed during the lockdown relative to toddlers'. Our data highlight a significant modulation of age on the impact of the pandemic crisis on sleep, with pre-schoolers experiencing greater effects than toddlers. This profile suggests that factors affecting sleep features have different weights at different ages: sleep patterns would be mainly determined by developmental factors (i.e., biological drive) in younger children, whereas environmental factors (e.g., major lifestyle changes) would have a stronger effect on older ones.

An epidemiological study of sleep-wake timings in school children from 4 to 11 years old: insights on the sleep phase shift and implications for the school starting times' debate.

OBJECTIVE: It has been assumed that during adolescence there is a strong shift toward eveningness chronotype, whereas children's sleep is relatively stable. Several studies have focused on the conflict between school start times and adolescents' circadian rhythms; however, fewer studies have been conducted in younger children. The aim of this study was to examine sleep durations, schedules, and sleep phase shift in preschool- and school-aged children. METHODS: Data for sleep patterns on school days and free days (ie, days when children's sleep-wake patterns were free from any influence of individual or family activities) was obtained by means of questionnaires (Children ChronoType Questionnaire) for 3155 Portuguese children 4-11 years of age. RESULTS: As children grew older and school grade level increases, we found later bedtimes and sleep onsets on both school days and free days; and later wake times only on free days. By contrast, wake times were progressively earlier, imposed by school start times. There was a progressive reduction in the amount of sleep on school nights as grade level increased. Greater social jetlag, later midpoint of sleep, and higher restriction-extension patterns were found across age groups. CONCLUSION: The displacement of bed and wake times for later hours on free days starts at an early age. Changing early school start times could adjust social demands to the biological rhythm of children.

Sleep schedules and school performance in Indigenous Australian children.

BACKGROUND: Sleep duration and sleep schedule variability have been related to negative health and well-being outcomes in children, but little is known about Australian Indigenous children. METHODS: Data for children aged 7-9 years came from the Australian Longitudinal Study of Indigenous Children and the National Assessment Program-Literacy and Numeracy (NAPLAN). Latent class analysis determined sleep classes taking into account sleep duration, bedtimes, waketimes, and variability in bedtimes from weekdays to weekends. Regression models tested whether the sleep classes were cross-sectionally associated with grade 3 NAPLAN scores. Latent change score modeling then examined whether the sleep classes predicted changes in NAPLAN performance from grades 3 to 5. RESULTS: Five sleep schedule classes were identified: normative sleep, early risers, long sleep, variable sleep, and short sleep. Overall, long sleepers performed best, with those with reduced sleep (short sleepers and early risers) performing the worse on grammar, numeracy, and writing performance. Latent change score results also showed that long sleepers performed best in spelling and writing and short sleepers and typical sleepers performed the worst over time. CONCLUSIONS: In this sample of Australian Indigenous children, short sleep was associated with poorer school performance compared with long sleep, with this performance worsening over time for some performance indicators. Other sleep schedules (eg, early wake times and variable sleep) also had some relationships with school performance. As sleep scheduling is modifiable, this offers opportunity for improvement in sleep and thus performance outcomes for these and potentially all children.

A global quantification of "normal" sleep schedules using smartphone data.

The influence of the circadian clock on sleep scheduling has been studied extensively in the laboratory; however, the effects of society on sleep remain largely unquantified. We show how a smartphone app that we have developed, ENTRAIN, accurately collects data on sleep habits around the world. Through mathematical modeling and statistics, we find that social pressures weaken and/or conceal biological drives in the evening, leading individuals to delay their bedtime and shorten their sleep. A country's average bedtime, but not average wake time, predicts sleep duration. We further show that mathematical models based on controlled laboratory experiments predict qualitative trends in sunrise, sunset, and light level; however, these effects are attenuated in the real world around bedtime. Additionally, we find that women schedule more sleep than men and that users reporting that they are typically exposed to outdoor light go to sleep earlier and sleep more than those reporting indoor light. Finally, we find that age is the primary determinant of sleep timing, and that age plays an important role in the variability of population-level sleep habits. This work better defines and personalizes "normal" sleep, produces hypotheses for future testing in the laboratory, and suggests important ways to counteract the global sleep crisis.