Live to the rhythm, slave to the rhythm

Social rhythm and implications on functionality of patients after stroke

The study aimed to assess the regularity, intensity, frequency, and period of activities comprising social rhythm and associate them with the functionality of stroke patients. The sample consisted of 73 patients (41 men and 32 women) with a mean age of 60 years (±10). Social rhythm was assessed by Social Rhythm Metric (SRM) and Activity Level Index (ALI). The functionality was evaluated using the International Classification of Functioning, Disability, and Health (ICF). Data were analyzed using Student's t-test, ANOVA, and Chi-square test. The mean SRM was 5.1 ± 0.9, and ALI was 58.3 ± 14.9. Notably, 40% of the patients exhibited both low regularity and low intensity of activities. Six SRM activities, performed with low frequency (going outside, starting work, exercising, snacking, watching other TV programs, and going home), exhibited a tendency to have periods that deviated from the expected 24-hour daily cycle. ICF domains most associated with SRM were: d2-General tasks and demands, d3-Communication, d4-Mobility, d5-Self care, d8-Major life areas, and d9-Community, social and civic life. The results indicated changes in social rhythm with implications for patient functionality. Screening for disruptions in social rhythm could be part of the functional assessment during the rehabilitation process for post-stroke patients.

Sleep problems and circadian rhythm functioning in autistic children, autism with co-occurring attention deficit hyperactivity disorder, and typically developing children: A comparative study

LAY ABSTRACT

Sleep problems are common in autism spectrum disorder (ASD) and different factors can contribute to its occurrence in this population. Misalignment of the biological clock (our circadian system) has been described as one possible explanation. While there is a body of research on sleep problems, relatively less is known about circadian functioning and the specific population of autistic children with co-occurring attention deficit hyperactivity disorder (ADHD). Using an ambulatory circadian monitoring (ACM) system, which resembles a common watch, we gathered sleep parameters and the different rhythms obtained from measuring motor activity, light exposure and distal temperature in 87 autistic children and adolescents, 27 of whom were diagnosed with co-occurring ADHD, and 30 neurotypical children and adolescents as a comparison group. Autistic children and, especially, those with co-occurring ADHD showed greater motor activity during sleep which would be worth studying in future projects which could better define this restless sleep. Of note, we observed an atypical pattern of wrist temperature, with higher values in neurotypical children, followed by autistic children and, ultimately, those with co-occurring ADHD. Temperature is one of the most valuable factors evaluated here as it is closely connected to sleep-wakefulness and the hormone melatonin. Its special pattern during day and nighttime would support the hypothesis of an atypical secretion of melatonin in autistic individuals which would also link with the higher presence of sleep problems in this neurodevelopmental condition.

Utilizing activity sensors to identify the behavioural activity patterns of elderly home care clients

PURPOSE

The behavioural activity pattern is a behavioural and biological 24-hour rhythm. Ageing, diseases and memory disorders can change this pattern. Home care staff can utilize knowledge about the behavioural activity pattern of elderly home care clients in many ways. The purpose of this study was to evaluate whether home care staff could identify the behavioural activity pattern of elderly home care clients using activity sensors, namely, actigraphs and motion sensors, could identify the behavioural activity rhythms.

MATERIALS AND METHODS

A total of four elderly home care clients and one elderly home rehabilitation client took part in the study. The participants wore actigraphs on their wrist and motion sensors were installed in their apartment. In addition to sensor data, home care staff answered one open-ended question during each home care visit. The data collection period was two weeks. Both quantitative and qualitative methods were used in the analysis.

RESULTS

The behavioural activity pattern was easy to identify from the motion sensor data, whereas actigraph data were difficult to interpret. The home care staff members' answers to open-ended questions reinforced the reliability of motion sensor data.

CONCLUSIONS

Motion sensors are relatively cheap, unobtrusive and reliable way to identify and detect changes in the behavioural activity patterns of elderly home care clients.Implications for rehabilitationMotion sensors are cheap, user-friendly and highly accepted technology for identifying and monitoring behavioural activity rhythm.Home care staff members can use the data about elderly home care client's behavioural activity rhythm to monitor deviations to the rhythm and detect changes in client's health.The information about behavioural activity rhythm can also be utilized in planning home care visits and interventions.

Response to Melatonin Treatment in Children With Autism spectrum Disorder and Relationship to Sleep Parameters and Melatonin Levels

Melatonin is one of the most used pharmacologic treatments for sleep problems in autism spectrum disorder, though its relationship with circadian and sleep parameters is still not well stablished. A naturalistic study was conducted in children with autism spectrum disorder, previously drug-naïve, before and after treatment with immediate-release melatonin. Circadian rhythms and sleep parameters were studied using an ambulatory circadian-monitoring device, and saliva samples were collected enabling determination of dim light melatonin onset. Twenty-six children with autism spectrum disorder (age 10.50  ±  2.91) were included. Immediate-release melatonin modified circadian rhythm as indicated by wrist skin temperature, showing an increase at night. A positive correlation was found between time of peak melatonin and sleep efficiency improvement values. Sleep-onset latency and efficiency improved with immediate-release melatonin. Immediate-release melatonin could be an effective treatment to improve sleep onset and restore a typical pattern of wrist temperature, which appears to be lost in autism spectrum disorder.

Intraday adaptation to extreme temperatures in outdoor activity

Linkages between climate and human activity are often calibrated at daily or monthly resolutions, which lacks the granularity to observe intraday adaptation behaviors. Ignoring this adaptation margin could mischaracterize the health consequences of future climate change. Here, we construct an hourly outdoor leisure activity database using billions of cell phone location requests in 10,499 parks in 2017 all over China to investigate the within-day outdoor activity rhythm. We find that hourly temperatures above 30 °C and 35 °C depress outdoor leisure activities by 5% (95% confidence interval, CI 3-7%) and by 13% (95% CI 10-16%) respectively. This activity-depressing effect is larger than previous daily or monthly studies due to intraday activity substitution from noon and afternoon to morning and evening. Intraday adaptation is larger for locations and dates with time flexibility, for individuals more frequently exposed to heat, and for parks situated in urban areas. Such within-day adaptation substantially reduces heat exposure, yet it also delays the active time at night by about half an hour, with potential side effect on sleep quality. Combining empirical estimates with outputs from downscaled climate models, we show that unmitigated climate change will generate sizable activity-depressing and activity-delaying effects in summer when projected on an hourly resolution. Our findings call for more attention in leveraging real-time activity data to understand intraday adaptation behaviors and their associated health consequences in climate change research.

Association between rest-activity rhythm and cognitive function in the elderly: The U.S. National Health and Nutrition Examination Survey, 2011-2014

BACKGROUND

Circadian rhythm plays an essential role in various physiological and pathological processes related to cognitive function. The rest-activity rhythm (RAR) is one of the most prominent outputs of the circadian system. However, little is known about the relationships between RAR and different domains of cognitive function in older adults. The purpose of this study was to examine the relationships between RAR and various fields of cognitive function in older Americans.

METHODS

This study included a total of 2090 older adults ≥ 60 years old from the National Health and Nutrition Examination Survey (NHANES) in 2011-2014. RAR parameters were derived from accelerometer recordings. Cognitive function was assessed using the word learning subtest developed by the Consortium to Establish a Registry for Alzheimer's disease (CERAD W-L), the Animal Fluency Test (AFT) and the Digital Symbol Substitution Test (DSST). Linear regression was used to determine the relationships between RAR parameters (IS, IV, RA, L5, M10) and cognitive function scores (CERAD W-L, AFT, DSST).

RESULTS

After adjusting for potential confounders, lower IS and M10 were associated with lower CERAD W-L scores (P=0.033 and P=0.002, respectively). Weaker RA and higher L5 were associated with lower AFT scores (P<0.001 and P=0.001, respectively). And lower IS, RA, and higher L5 were associated with lower DSST scores (P=0.019, P<0.001 and P<0.001, respectively). In addition, the results of sensitivity analysis were similar to those of our main analyses. The main correlation results between the RAR indicators and cognitive function were robust.

CONCLUSIONS

This study suggested that the weakened and/or disrupted RAR was associated with cognitive decline in different domains in Americans over the age of 60.

Practice recommendations for the role of physiotherapy in the management of sleep disorders: the 2022 Brazilian Sleep Association Guidelines

This clinical guideline supported by the Brazilian Sleep Association comprises a brief history of the development of Brazilian sleep physiotherapy, outlines the role of the physiotherapist as part of a sleep health team, and describes the clinical guidelines in respect of the management of some sleep disorders by the physiotherapist (including sleep breathing disorders, i.e., obstructive sleep apnea, central sleep apnea, upper airway resistance syndrome, hypoventilation syndromes and overlap syndrome, and pediatric sleep breathing disorders; sleep bruxism; circadian rhythms disturbances; insomnia; and Willis-Ekbom disease/periodic limb movement disorder. This clinical practice guideline reflects the state of the art at the time of publication and will be reviewed and updated as new information becomes available.

Melatonin Rhythm and Its Relation to Sleep and Circadian Parameters in Children and Adolescents With Autism Spectrum Disorder

Introduction

Sleep problems are prevalent among individuals with autism spectrum disorder (ASD), and a role has been attributed to melatonin in this multifactorial comorbidity.

Methods

A cross-sectional study was conducted on 41 autistic children and adolescents (9.9 ± 3.02) and 24 children and adolescents with a normal intellectual function (8.42 ± 2.43) were used as controls. Subjects were matched for sex, body mass index, and pubertal stage, and all were drug-naive. Circadian and sleep parameters were studied using an ambulatory circadian monitoring (ACM) device, and saliva samples were collected around the onset of sleep to determine dim light melatonin onset (DLMO).

Results

Prepubertal individuals with ASD presented later DLMO and an earlier decline in melatonin during adolescence. A relationship was found between melatonin and both sleep and circadian parameters. Participants and controls with later DLMOs were more likely to have delayed sleep onset times. In the ASD group, subjects with the later daytime midpoint of temperature had a later DLMO. Later melatonin peak time and DLMO time were related to lower general motor activity and lower stability of its rhythms.

Conclusion

The melatonin secretion pattern was different in individuals with ASD, and it showed a relationship with sleep and circadian parameters. Alterations in DLMO have not been previously reported in ASD with the exception of more variable DLMO timing; however, high variability in the study design and sample characteristics prevents direct comparison. The ACM device enabled the measurement of circadian rhythm, a scarcely described parameter in autistic children. When studied in combination with other measures such as melatonin, ACM can offer further knowledge on sleep problems in ASD.

Relationship Between Circadian Strain, Light Exposure, and Body Mass Index in Rural and Urban Quilombola Communities

Industrialization has greatly changed human lifestyle; work and leisure activities have been moved indoors, and artificial light has been used to illuminate the night. As cyclic environmental cues such as light and feeding become weak and/or irregular, endogenous circadian systems are increasingly being disrupted. These disruptions are associated with metabolic dysfunction, possibly contributing to increased rates of overweight and obesity worldwide. Here, we aimed to investigate how activity-rest rhythms, patterns of light exposure, and levels of urbanization may be associated with body mass index (BMI) in a sample of rural and urban Quilombola communities in southern Brazil. These are characterized as remaining social groups who resisted the slavery regime that prevailed in Brazil. Quilombola communities were classified into five groups according to their stage of urbanization: from rural areas with no access to electricity to highly urbanized communities. We collected anthropometric data to calculate BMI, which was categorized as follows: from ≥ 18.5 kg/m² to < 25 kg/m² = normal weight; from ≥ 25 kg/m² to < 30 kg/m² = overweight; and ≥ 30 kg/m² = obese. Subjects were asked about their sleep routines and light exposure on workdays and work-free days using the Munich Chronotype Questionnaire (N = 244 included). In addition, we analyzed actimetry data from 121 participants with seven consecutive days of recordings. Living in more urbanized areas and higher intradaily variability (IV) of activity-rest rhythms were associated with an increased risk of belonging to the overweight or obese group, when controlling for age and sex. These findings are consistent with preclinical data and point to potential strategies in obesity prevention and promotion of healthy metabolic profiles.

Sleep Problems and Circadian Functioning in Children and Adolescents With Autism Spectrum Disorder

BACKGROUND

Sleep problems are a prevalent comorbidity in autism spectrum disorder (ASD) with a multifactorial basis in which circadian misalignment has been described.

METHODS

A cross-sectional study was conducted including 52 children and adolescents with ASD (9.85 ± 3.07) and 27 children and adolescent controls with normal intellectual functioning (8.81 ± 2.14). They were matched for age, sex, and body mass index, and all were drug-naïve. An ambulatory circadian monitoring device was used to record temperature and motor, body position, sleep, and light intensity.

RESULTS

Individuals with ASD presented longer sleep-onset latency, lower sleep efficiency, and decreased total sleep time and tended to be more sedentary and have less exposure to light. They also showed lower amplitude, low interdaily stability, and a different pattern of wrist temperature across the day, with a midpoint of sleep that did not concur with sleep midpoint indicated by the rest of circadian parameters.

CONCLUSIONS

The sleep problems observed in this sample resemble those reported previously, with the exception of nocturnal awakenings which did not show differences. The ambulatory circadian monitoring device enabled measurement of circadian parameters such as temperature which, until now, were scarcely described in children with ASD and could be used to better understand sleep and circadian system in ASD.

The Effect of Bright Light Treatment on Rest-Activity Rhythms in People with Dementia: A 24-Week Cluster Randomized Controlled Trial

Bright light treatment is an effective way to influence circadian rhythms in healthy adults, but previous research with dementia patients has yielded mixed results. The present study presents a primary outcome of the DEM.LIGHT trial, a 24-week randomized controlled trial conducted at nursing homes in Bergen, Norway, investigating the effects of a bright light intervention. The intervention consisted of ceiling-mounted LED panels providing varying illuminance and correlated color temperature throughout the day, with a peak of 1000 lx, 6000 K between 10 a.m. and 3 p.m. Activity was recorded using actigraphs at baseline and after 8, 16, and 24 weeks. Non-parametric indicators and extended cosine models were used to investigate rest-activity rhythms, and outcomes were analyzed with multi-level regression models. Sixty-one patients with severe dementia (median MMSE = 4) were included. After 16 weeks, the acrophase was advanced from baseline in the intervention group compared to the control group (B = -1.02, 95%; CI = -2.00, -0.05). There was no significant difference between the groups on any other rest-activity measures. When comparing parametric and non-parametric indicators of rest-activity rhythms, 25 out of 35 comparisons were significantly correlated. The present results indicate that ambient bright light treatment did not improve rest-activity rhythms for people with dementia.

Are we still in the dark? A systematic review on personal daily light exposure, sleep-wake rhythm, and mood in healthy adults from the general population

Insufficient light exposure is assumed to be related to a wide array of health problems, though few studies focus on the role of whole-day light exposure in the habitual setting in the development of these health problems. The current review aims to describe the association between personal light exposure in the habitual setting and sleep-wake rhythm and mood in healthy adults from the general population. Five databases (Embase, Medline Epub, Web of Science, PsycINFO, and Google Scholar) were searched in June 2019. The inclusion criteria included: assessment directly of light exposure on the participants for at least one full day; reporting on both individual personal light exposure and outcomes. The quality of the papers was assessed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies of the National Heart, Lung and Blood Institute. The current review followed the PRISMA guidelines. In total, 8140 papers were identified in the database search. Twenty-five papers were eventually included in this review. All included studies were cross-sectional, and individual light exposure was usually measured with a wrist-worn device. Five studies received a "good" quality rating, 16 received a "fair" rating, and the remaining 4 a "poor" quality rating. The overall quality of the included studies was considered low because of the lack of intervention studies and the fact that light exposure was measured on the wrist. Given the low quality of the included studies, the current review can only provide a first exploration on the association between light exposure and sleep-wake rhythm and mood in healthy adults from the general population. Limited evidence is presented for a positive relationship between the amount and timing of light exposure on the one hand and rest-activity rhythm and some estimates of sleep architecture on the other. The evidence on an association between light exposure and circadian phase, sleep estimates, sleep quality, and mood is conflicting. Data from intervention studies are needed to gain insight into the causal mechanism of the relationship between light exposure and sleep-wake rhythm and mood.

Dementia Enlightened?! A Systematic Literature Review of the Influence of Indoor Environmental Light on the Health of Older Persons with Dementia in Long-Term Care Facilities

Light therapy for older persons with dementia is often administered with light boxes, even though indoor ambient light may more comfortably support the diverse lighting needs of this population. Our objective is to investigate the influence of indoor daylight and lighting on the health of older adults with dementia living in long-term care facilities. A systematic literature search was performed within PubMed, CINAHL, PsycINFO, Web of Science and Scopus databases. The included articles (n=37) were published from 1991 to 2020. These articles researched the influence of existing and changed indoor light conditions on health and resulted in seven categories of health outcomes. Although no conclusive evidence was found to support the ability of indoor light to decrease challenging behaviors or improve circadian rhythms, findings of two studies indicate that exposure to (very) cool light of moderate intensity diminished agitation. Promising effects of indoor light were to reduce depressive symptoms and facilitate spatial orientation. Furthermore, there were indications that indoor light improved one’s quality of life. Despite interventions with dynamic lighting having yielded little evidence of its efficacy, its potential has been insufficiently researched among this study population. This review provides a clear and comprehensive description of the impact of diverse indoor light conditions on the health of older adults with dementia living in long-term care facilities. Variation was seen in terms of research methods, (the description of) light conditions, and participants’ characteristics (types and severity of dementia), thus confounding the reliability of the findings. The authors recommend further research to corroborate the beneficial effects of indoor light on depression and to clarify its role in supporting everyday activities of this population. An implication for practice in long-term care facilities is raising the awareness of the increased lighting needs of aged residents.

Cross-sectional and prospective associations between sleep regularity and metabolic health in the Hispanic Community Health Study/Study of Latinos

STUDY OBJECTIVES

Sleep is an emergent, multi-dimensional risk factor for diabetes. Sleep duration, timing, quality, and insomnia have been associated with diabetes risk and glycemic biomarkers, but the role of sleep regularity in the development of metabolic disorders is less clear.

METHODS

We analyzed data from 2107 adults, aged 19-64 years, from the Sueño ancillary study of the Hispanic Community Health Study/Study of Latinos, followed over a mean of 5.7 years. Multivariable-adjusted complex survey regression methods were used to model cross-sectional and prospective associations between the sleep regularity index (SRI) in quartiles (Q1-least regular, Q4-most regular) and diabetes (either laboratory-confirmed or self-reported antidiabetic medication use), baseline levels of insulin resistance (HOMA-IR), beta-cell function (HOMA-β), hemoglobin A1c (HbA1c), and their changes over time.

RESULTS

Cross-sectionally, lower SRI was associated with higher odds of diabetes (odds ratio [OR]Q1 vs. Q4 = 1.64, 95% CI: 0.98-2.74, ORQ2 vs. Q4 = 1.12, 95% CI: 0.70-1.81, ORQ3 vs. Q4 = 1.00, 95% CI: 0.62-1.62, ptrend = 0.023). The SRI effect was more pronounced in older (aged ≥ 45 years) adults (ORQ1 vs. Q4 = 1.88, 95% CI: 1.14-3.12, pinteraction = 0.060) compared to younger ones. No statistically significant associations were found between SRI and diabetes incidence, as well as baseline HOMA-IR, HOMA-β, and HbA1c values, or their changes over time among adults not taking antidiabetic medication.

CONCLUSIONS

Our results suggest that sleep regularity represents another sleep dimension relevant for diabetes risk. Further research is needed to elucidate the relative contribution of sleep regularity to metabolic dysregulation and pathophysiology.

The efficacy of combined bright light and melatonin therapies on sleep and circadian outcomes: A systematic review

The aim of this systematic review was to investigate the effects of combined melatonin and bright light therapies on improved sleep and circadian outcomes. We conducted a systematic review that resulted in a total of eight papers meeting criteria. Four papers investigated the effectiveness of combined therapy in inducing a circadian phase shift on healthy participants. Combined therapy outperformed single light and melatonin therapies in phase advancing, but not in delaying, dim light melatonin onset (DLMO). The other four papers investigated the effect of combined therapy on sleep outcomes. Two of them were performed in elderly populations suffering from cognitive decline and two in delayed sleep-wake phase disorder (DSWPD) patients. While combined therapy was more beneficial than single therapy in elderly populations it did not show any benefit in DSWPD patients. The reported adverse effects of melatonin in elderly populations must be carefully considered. Future studies should investigate the separate and combined effect of melatonin and bright light on sleep and circadian outcomes in different target populations.

Quantifying Circadian Aspects of Mobility-Related Behavior in Older Adults by Body-Worn Sensors-An "Active Period Analysis"

Disruptions of circadian motor behavior cause a significant burden for older adults as well as their caregivers and often lead to institutionalization. This cross-sectional study investigates the association between mobility-related behavior and subjectively rated circadian chronotypes in healthy older adults. The physical activity of 81 community-dwelling older adults was measured over seven consecutive days and nights using lower-back-worn hybrid motion sensors (MM+) and wrist-worn actigraphs (MW8). A 30-min and 120-min active period for the highest number of steps (MM+) and activity counts (MW8) was derived for each day, respectively. Subjective chronotypes were classified by the Morningness-Eveningness Questionnaire into 40 (50%) morning types, 35 (43%) intermediate and six (7%) evening types. Analysis revealed significantly earlier starts for the 30-min active period (steps) in the morning types compared to the intermediate types (p ≤ 0.01) and the evening types (p ≤ 0.01). The 120-min active period (steps) showed significantly earlier starts in the morning types compared to the intermediate types (p ≤ 0.01) and the evening types (p = 0.02). The starting times of active periods determined from wrist-activity counts (MW8) did not reveal differences between the three chronotypes (p = 0.36 for the 30-min and p = 0.12 for the 120-min active period). The timing of mobility-related activity, i.e., periods with the highest number of steps measured by hybrid motion sensors, is associated to subjectively rated chronotypes in healthy older adults. The analysis of individual active periods may provide an innovative approach for early detecting and individually tailoring the treatment of circadian disruptions in aging and geriatric healthcare.

Circadian Misalignment Induced by Chronic Night Shift Work Promotes Endoplasmic Reticulum Stress Activation Impacting Directly on Human Metabolism

Simple Summary

The demands of modern society have made shift work a necessity. Night work is associated with an increased risk of metabolic problems such as obesity and diabetes, which is mainly due to the misalignment of circadian rhythms that play a crucial role in many biological processes. This study performed clinical, anthropometric, and molecular analyses on 40 hospital workers who work day or night. We demonstrated that night workers had increased glucose levels, triglycerides, waist circumference, and blood pressure compared to day workers. Surprisingly, we report that night workers have significant changes in the expression of circadian clock genes and an up-regulation of genes related to endoplasmic reticulum stress (ERS). These findings provide new insights into the effects of night shift work on the expression of circadian cycle genes and ERS activation, leading to metabolic stress and the development of metabolic diseases associated with night work.

Abstract

Night work has become necessary in our modern society. However, sleep deprivation induces a circadian misalignment that effectively contributes to the development of diseases associated with metabolic syndrome, such as obesity and diabetes. Here, we evaluated the pattern of circadian clock genes and endoplasmic reticulum stress (ERS) genes in addition to metabolic and anthropometric measures in subjects that work during a nocturnal period compared with day workers. We study 20 night workers (NW) and 20 day workers (DW) submitted to a work schedule of 12 h of work for 36 h of rest for at least 5 years in a hospital. The present report shows that NW have increased fasting blood glucose, glycated hemoglobin (HbA1c), triglycerides, and low-density lipoprotein (LDL)-cholesterol levels, and lower high-density lipoprotein (HDL)-cholesterol levels compared to DW. In addition, we observed that waist circumference (WC), waist–hip ratio (WHR), and systemic blood pressure are also increased in NW. Interestingly, gene expression analysis showed changes in CLOCK gene expression in peripheral blood mononuclear cells (PBMC) samples of NW compared to the DW, evidencing a peripheral circadian misalignment. This metabolic adaptation was accompanied by the up-regulation of many genes of ERS in NW. These findings support the hypothesis that night shift work results in disturbed glycemic and lipid control and affects the circadian cycle through the deregulation of peripheral CLOCK genes, which is possibly due to the activation of ERS. Thus, night work induces important metabolic changes that increase the risk of developing metabolic syndrome.

Large cognitive fluctuations surrounding sleep in daily living

Cognitive output and physical activity levels fluctuate surrounding sleep. The ubiquitous digitization of behavior via smartphones is a promising avenue for addressing how these fluctuations occur in daily living. Here, we logged smartphone touchscreen interactions to proxy cognitive fluctuations and contrasted these to physical activity patterns logged on wrist-worn actigraphy. We found that both cognitive and physical activities were dominated by diurnal (∼24 h) and infra-radian (∼7 days) rhythms. The proxy measures of cognitive performance—tapping speed, unlocking speed, and app locating speed—contained lower-powered diurnal rhythm than physical activity. The difference between cognitive and physical activity was vivid during bedtime as people continued to interact with their smartphones at physical rest. The cognitive performance measures in this period were worse than those in the hour before or after bedtime. We suggest that the rhythms underlying cognitive activity in the real world are distinct from those underlying physical activity, and this discord may be a hallmark of modern human behavior.

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Daily and weekly rhythms shape our day-to-day behavior

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The speed of smartphone interactions fluctuates according to the time of the day

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These fluctuations do not strictly follow the physical activity cycles

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The worst performing time on the smartphone is around bedtime

Differential associations of age and Alzheimer's disease with sleep and rest-activity rhythms across the adult lifespan

This study aimed to identify differences between physiological age-related and Alzheimer's disease (AD)-related alterations in sleep and rest-activity rhythm. All participants (n = 280; 20-90 years) underwent clinical assessments, [¹¹C] Pittsburgh compound B-positron emission tomography, and actigraphic monitoring. In cognitively normal adults without cerebral amyloid-β, older age was associated with earlier timing of circadian phase and robust rest-activity rhythm, but sleep quantity and quality were mostly unaffected by age. While preclinical AD was associated with earlier circadian timing, clinical AD exhibited later timing of daily rhythm and increased sleep duration. In conclusion, our findings suggest that older age itself leads to a more regular daily activity rhythm, but does not affect sleep duration. While preclinical AD made the effects of age-related phase advance more prominent, clinical AD was related to later circadian timing and increased sleep duration.

Light in the Senior Home: Effects of Dynamic and Individual Light Exposure on Sleep, Cognition, and Well-Being

Disrupted sleep is common among nursing home patients and is associated with cognitive decline and reduced well-being. Sleep disruptions may in part be a result of insufficient daytime light exposure. This pilot study examined the effects of dynamic “circadian” lighting and individual light exposure on sleep, cognitive performance, and well-being in a sample of 14 senior home residents. The study was conducted as a within-subject study design over five weeks of circadian lighting and five weeks of conventional lighting, in a counterbalanced order. Participants wore wrist accelerometers to track rest–activity and light profiles and completed cognitive batteries (National Institute of Health (NIH) toolbox) and questionnaires (depression, fatigue, sleep quality, lighting appraisal) in each condition. We found no significant differences in outcome variables between the two lighting conditions. Individual differences in overall (indoors and outdoors) light exposure levels varied greatly between participants but did not differ between lighting conditions, except at night (22:00–6:00), with maximum light exposure being greater in the conventional lighting condition. Pooled data from both conditions showed that participants with higher overall morning light exposure (6:00–12:00) had less fragmented and more stable rest–activity rhythms with higher relative amplitude. Rest–activity rhythm fragmentation and long sleep duration both uniquely predicted lower cognitive performance.

Internet-guided cognitive, behavioral and chronobiological interventions in depression-prone insomnia subtypes: protocol of a randomized controlled prevention trial

BACKGROUND

Major depressive disorder is among the most burdening and costly chronic health hazards. Since its prognosis is poor and treatment effectiveness is moderate at best, prevention would be the strategy of first choice. Insomnia may be the best modifiable risk factor. Insomnia is highly prevalent (4-10%) and meta-analysis estimates ±13% of people with insomnia to develop depression within a year. Among people with insomnia, recent work identified three subtypes with a particularly high lifetime risk of depression. The current randomized controlled trial (RCT) evaluates the effects of internet-guided Cognitive Behavioral Therapy for Insomnia (CBT-I), Chronobiological Therapy (CT), and their combination on insomnia and the development of depressive symptoms.

METHODS

We aim to include 120 participants with Insomnia Disorder (ID) of one of the three subtypes that are more prone to develop depression. In a two by two factorial repeated measures design, participants will be randomized to CBT-I, CT, CBT-I + CT or treatment as usual, and followed up for one year. The primary outcome is the change, relative to baseline, of the severity of depressive symptoms integrated over four follow-ups spanning one year. Secondary outcome measures include a diagnosis of major depressive disorder, insomnia severity, sleep diaries, actigraphy, cost-effectiveness, and brain structure and function.

DISCUSSION

Pre-selection of three high-risk insomnia subtypes allows for a sensitive assessment of the possibility to prevent the development and worsening of depressive symptoms through interventions targeting insomnia.

TRIAL REGISTRATION

Netherlands Trial Register (NL7359). Registered on 19 October 2018.

Disease-Associated Mutant Tau Prevents Circadian Changes in the Cytoskeleton of Central Pacemaker Neurons

A hallmark feature of Alzheimer's disease (AD) and other Tauopathies, like Frontotemporal Dementia with Parkinsonism linked to chromosome 17 (FTDP-17), is the accumulation of neurofibrillary tangles composed of the microtubule-associated protein Tau. As in AD, symptoms of FTDP-17 include cognitive decline, neuronal degeneration, and disruptions of sleep patterns. However, mechanisms by which Tau may lead to these disturbances in sleep and activity patterns are unknown. To identify such mechanisms, we have generated novel Drosophila Tauopathy models by replacing endogenous fly dTau with normal human Tau (hTau) or the FTDP-17 causing hTau^V337M mutation. This mutation is localized in one of the microtubule-binding domains of hTau and has a dominant effect. Analyzing heterozygous flies, we found that aged hTau^V337M flies show neuronal degeneration and locomotion deficits when compared to wild type or hTau^WT flies. Furthermore, hTau^V337M flies are hyperactive and they show a fragmented sleep pattern. These changes in the sleep/activity pattern are accompanied by morphological changes in the projection pattern of the central pacemaker neurons. These neurons show daily fluctuations in their connectivity, whereby synapses are increased during the day and reduced during sleep. Synapse formation requires cytoskeletal changes that can be detected by the accumulation of the end-binding protein 1 (EB1) at the site of synapse formation. Whereas, hTau^WT flies show the normal day/night changes in EB1 accumulation, hTau^V337M flies do not show this fluctuation. This suggests that hTau^V337M disrupts sleep patterns by interfering with the cytoskeletal changes that are required for the synaptic homeostasis of central pacemaker neurons.

Obesity and Circadian Cycle of Sleep and Wakefulness: Common Points and Prospects of Therapy

The prevalence of obesity in recent years has assumed the character of a non-communicable epidemic. Wherein, the standard approaches for its treatment are not always successful. Meanwhile, obesity remains one of the main causes of the formation of a number of some serious diseases, such as cardiovascular, diabetes, cancer, etc. and death from them. In search of alternative and more adequate methods of obesity treatment and preventing its complications, recent studies are aimed at further identifying new associations and revealing the pathophysiological mechanisms underlying excessive weight gain. It should be noted an increasing amount of chronobiological studies that raised awareness of the key role of the body’s circadian rhythms and its main regulator, melatonin, responsible for the temporary organization of the main physiological (including metabolism) processes throughout the 24-h day, in the development and progression of obesity. This review is devoted to the consideration of mutually directed interactions between the circadian system and metabolism; attempts have been made to explain the role of sleep-wake cycle disruptions in the excess accumulation of adipose tissue and the formation of obesity and its comorbidities, as well as detailed therapeutic principles based on normalizing disruption of body clocks using time-coordinated approaches to food intake, physical activity, the effects of non-drug methods and pharmacological substances (chronobiotics), which represents a novel and promising ways to prevent or treat obesity and associated diseases.

24-h Activity Rhythms and Health in Older Adults

Purpose of Review

Circadian rhythms, including 24-h activity rhythms, change with age. Disturbances in these 24-h activity rhythms at older age have also been implied in various diseases. This review evaluates recent findings on 24-h activity rhythms and disease in older adults.

Recent Findings

Growing evidence supports that 24-h activity rhythm disturbances at older age are related to the presence and/or progression of disease. Longitudinal and genetic work even suggests a potential causal contribution of disturbed 24-h activity rhythms to disease development. Interventional studies targeting circadian and 24-h activity rhythms demonstrate that 24-h rhythmicity can be improved, but the effect of improving 24-h rhythmicity on disease risk or progression remains to be shown.

Summary

Increasing evidence suggests that 24-h activity rhythms are involved in age-related diseases. Further studies are needed to assess causality, underlying mechanisms, and the effects of treating disturbed 24-h activity rhythms on age-related disease.

Evaluation of agomelatine for the treatment of sleep problems in adults with autism spectrum disorder and co-morbid intellectual disability

PURPOSE

Intellectual disability (ID) and autism spectrum disorder (ASD) are common, co-occurring developmental disorders and are frequently associated with sleep problems. This study aimed to assess the effectiveness and tolerability of agomelatine as a pharmacotherapy for sleep problems in ASD adults with ID.

METHOD

A randomised, crossover, triple-blind, placebo-controlled clinical trial, with two three-month periods of treatment starting with either agomelatine or placebo and a washout period of two weeks. Ambulatory circadian monitoring (24 hours/7 days) evaluated total sleep time (TST) as the primary outcome variable.

RESULTS

Participants (N=23; 35±12 years old; 83% male) had a median of three (interquartile range (IQR) 1-4) co-morbidities and were taking a median of five (IQR 2-7) prescribed drugs. Before agomelatine or placebo treatment, all subjects presented with insomnia symptoms, including sleep latency (100% abnormal, 55±23 minutes) or TST (55% abnormal, 449±177 minutes), and 66% had circadian rhythm sleep-wake abnormalities with rhythm phase advancements according to the M5 sleep phase marker values. During the three-month agomelatine treatment, night TST significantly increased by a mean of 83 minutes (16% abnormal, 532±121 minutes), together with a phase correction (M5 1:45±2:28 hours vs. 3:15±2:20 hours), improving sleep stability in wrist temperature rhythm (0.43±0.29 vs. 0.52±0.18 AU). Adverse events were mild and transient.

CONCLUSIONS

Agomelatine was effective and well tolerated for treating insomnia and circadian rhythm sleep problems present in adults with ASD and ID.

Biological Rhythm Disruption Associated with Obesity in School Children

BACKGROUND

Biological rhythm is the daily metabolic cycle of mammals that involves the sleep-wake cycles, hormone release, eating habits and digestion, body temperature, and other important bodily functions that are repeated daily. Thus, greater difficulty in maintaining the circadian rhythms may be involved in the increased risk of obesity. This study assessed the association between biological rhythm disruption and childhood obesity among school children.

METHODS

This is a cross-sectional study with 7-8-year-old school children enrolled in a public school in the city of Pelotas-RS. The sample was drawn through multistage sampling. The Biological Rhythms Interview of Assessment in Neuropsychiatry-Kids (BRIAN-Kids) was used to assess the degree of difficulty maintaining the biological rhythm. BMI was calculated as weight/height² (kg/m²).

RESULTS

A total of 596 children and their caregivers participated in this study. The prevalence of obesity was 24% among school children, 28.9% for girls, and 19.4 for boys (p = 0.009). Obese children had greater difficulties in maintaining the biological rhythm compared to nonobese children (p = 0.007). Some of these difficulties included sleep (p = 0.008), overall activities (p = 0.027), social rhythm (p = 0.033), and eating (p = 0.032) pattern.

CONCLUSION

Approximately one-quarter of children were obese. This finding was associated with the caregiver characteristics and some difficulties in maintaining the biological rhythm.

Association of Time-Varying Rest-Activity Rhythm With Survival in Older Adults With Lung Cancer

BACKGROUND

To the best of our knowledge, this is the first study to examine the relationship of rest-activity rhythm with survival in older adults with lung cancer and to consider variations in rest-activity rhythm over time.

OBJECTIVE

The aim of this study was to explore the relationship between rest-activity rhythm variations and survival in 33 older adults with lung cancer by considering rest-activity rhythm as a time-dependent covariate over time.

METHODS

In this prospective study with 5 repeated measurements, patients' rest-activity rhythm over 3 days was measured using actigraphy. The rest-activity rhythm was represented using the dichotomy index I (in-bed activity) < O (out-of-bed activity). The median I < O was used as the cutoff point, with an I < O of greater than or equal to 85.59% and less than 85.59% indicating robust and disrupted rest-activity rhythms, respectively. Data were analyzed using the Cox regression model with time-dependent repeated measurements of a covariate.

RESULTS

In the time-dependent multivariate Cox model, a disrupted rest-activity rhythm was independently associated with a higher risk of death than was a robust rest-activity rhythm (hazard ratio, 16.05; P = .009).

CONCLUSION

A time-varying rest-activity rhythm is incrementally associated with mortality in older adults with lung cancer and represents a rigorous and independent prognostic factor for their survival.

IMPLICATIONS FOR PRACTICE

Clinicians may need to pay more attention to the rest-activity rhythms of older adults with lung cancer during disease progression. Future studies should account for the variation in rest-activity rhythm over time.

Sleep problems in adults with autism spectrum disorder and intellectual disability

Sleep problems (SP) are recognized as a common comorbid condition in autism spectrum disorder (ASD) and can influence core autism symptoms and mental and physical health. SPs can be lifelong and have been reported that adults on the autistic spectrum with and without intellectual disability (ID) present SPs (longer sleep latency, frequent night awakenings, and circadian rhythm sleep-wake disorders). A prospective, objective sleep study was conducted in 41 adults with ASD (33 ± 6 years old) and ID and 51 typically developing adults (33 ± 5 years old) using ambulatory circadian monitoring (ACM) recording wrist temperature, motor activity, body position, sleep, and light intensity. The findings indicated that individuals with ASD presented sleep difficulties including low sleep efficiency, prolonged sleep latency and increased number and length of night awakenings, together with daily sedentary behavior, and increased nocturnal activity. Furthermore, indications of an advanced sleep-wake phase disorder were found in these autistic adults. Examining sleep and markers of the circadian system showed significant differences between adults with ASD and ID and an age-matched, healthy adult population. The sleep disturbances described for this sample of adults with ASD and ID are similar to those of already described for adults with ASD without ID; their relationship with intellectual ability should be further studied. Improving knowledge of sleep patterns in ASD adults with ID might help to designed targeted interventions to improve their functioning and reduce family stress. Autism Research 2019, 12: 66-79. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: SPs are very frequent in autism from childhood to adulthood. We recorded sleep with a watch-like device in adults with autism and ID and compared sleep patterns with nonautistic volunteers. Results showed poorer sleep conditions in adults with autism (increased sleep latency and number/length of night awakenings) that resulted in decreased sleep efficiency. Increasing knowledge of the SPs in adults on the autism spectrum will allow to improve their and their families' quality of life.

Dim Light at Night and Constant Darkness: Two Frequently Used Lighting Conditions That Jeopardize the Health and Well-being of Laboratory Rodents

The influence of light on mammalian physiology and behavior is due to the entrainment of circadian rhythms complemented with a direct modulation of light that would be unlikely an outcome of circadian system. In mammals, physiological and behavioral circadian rhythms are regulated by the suprachiasmatic nucleus (SCN) of the hypothalamus. This central control allows organisms to predict and anticipate environmental change, as well as to coordinate different rhythmic modalities within an individual. In adult mammals, direct retinal projections to the SCN are responsible for resetting and synchronizing physiological and behavioral rhythms to the light-dark (LD) cycle. Apart from its circadian effects, light also has direct effects on certain biological functions in such a way that the participation of the SCN would not be fundamental for this network. The objective of this review is to increase awareness, within the scientific community and commercial providers, of the fact that laboratory rodents can experience a number of adverse health and welfare outcomes attributed to commonly-used lighting conditions in animal facilities during routine husbandry and scientific procedures, widely considered as “environmentally friendly.” There is increasing evidence that exposure to dim light at night, as well as chronic constant darkness, challenges mammalian physiology and behavior resulting in disrupted circadian rhythms, neural death, a depressive-behavioral phenotype, cognitive impairment, and the deregulation of metabolic, physiological, and synaptic plasticity in both the short and long terms. The normal development and good health of laboratory rodents requires cyclical light entrainment, adapted to the solar cycle of day and night, with null light at night and safe illuminating qualities during the day. We therefore recommend increased awareness of the limited information available with regards to lighting conditions, and therefore that lighting protocols must be taken into consideration when designing experiments and duly highlighted in scientific papers. This practice will help to ensure the welfare of laboratory animals and increase the likelihood of producing reliable and reproducible results.

Solar insolation in springtime influences age of onset of bipolar I disorder

OBJECTIVE

To confirm prior findings that the larger the maximum monthly increase in solar insolation in springtime, the younger the age of onset of bipolar disorder.

METHOD

Data were collected from 5536 patients at 50 sites in 32 countries on six continents. Onset occurred at 456 locations in 57 countries. Variables included solar insolation, birth-cohort, family history, polarity of first episode and country physician density.

RESULTS

There was a significant, inverse association between the maximum monthly increase in solar insolation at the onset location, and the age of onset. This effect was reduced in those without a family history of mood disorders and with a first episode of mania rather than depression. The maximum monthly increase occurred in springtime. The youngest birth-cohort had the youngest age of onset. All prior relationships were confirmed using both the entire sample, and only the youngest birth-cohort (all estimated coefficients P < 0.001).

CONCLUSION

A large increase in springtime solar insolation may impact the onset of bipolar disorder, especially with a family history of mood disorders. Recent societal changes that affect light exposure (LED lighting, mobile devices backlit with LEDs) may influence adaptability to a springtime circadian challenge.

Attenuation of short wavelengths alters sleep and the ipRGC pupil response

PURPOSE

Exposure to increasing amounts of artificial light during the night may contribute to the high prevalence of reported sleep dysfunction. Release of the sleep hormone melatonin is mediated by the intrinsically photosensitive retinal ganglion cells (ipRGCs). This study sought to investigate whether melatonin level and sleep quality can be modulated by decreasing night-time input to the ipRGCs.

METHODS

Subjects (ages 17-42, n = 21) wore short wavelength-blocking glasses prior to bedtime for 2 weeks. The ipRGC-mediated post illumination pupil response was measured before and after the experimental period. Stimulation was presented with a ganzfeld stimulator, including one-second and five-seconds of long and short wavelength light, and the pupil was imaged with an infrared camera. Pupil diameter was measured before, during and for 60 s following stimulation, and the six-second and 30 s post illumination pupil response and area under the curve following light offset were determined. Subjects wore an actigraph device for objective measurements of activity, light exposure, and sleep. Saliva samples were collected to assess melatonin content. The Pittsburgh Sleep Quality Index (PSQI) was administered to assess subjective sleep quality.

RESULTS

Subjects wore the blue-blocking glasses 3:57 ± 1:03 h each night. After the experimental period, the pupil showed a slower redilation phase, resulting in a significantly increased 30 s post illumination pupil response to one-second short wavelength light, and decreased area under the curve for one and five-second short wavelength light, when measured at the same time of day as baseline. Night time melatonin increased from 16.1 ± 7.5 pg mL^-1 to 25.5 ± 10.7 pg mL^-1 (P < 0.01). Objectively measured sleep duration increased 24 min, from 408.7 ± 44.9 to 431.5 ± 42.9 min (P < 0.001). Mean PSQI score improved from 5.6 ± 2.9 to 3.0 ± 2.2.

CONCLUSIONS

The use of short wavelength-blocking glasses at night increased subjectively measured sleep quality and objectively measured melatonin levels and sleep duration, presumably as a result of decreased night-time stimulation of ipRGCs. Alterations in the ipRGC-driven pupil response suggest a shift in circadian phase. Results suggest that minimising short wavelength light following sunset may help in regulating sleep patterns.

Sleep-Wake Disturbances After Traumatic Brain Injury: Synthesis of Human and Animal Studies

Sleep-wake disturbances following traumatic brain injury (TBI) are increasingly recognized as a serious consequence following injury and as a barrier to recovery. Injury-induced sleep-wake disturbances can persist for years, often impairing quality of life. Recently, there has been a nearly exponential increase in the number of primary research articles published on the pathophysiology and mechanisms underlying sleep-wake disturbances after TBI, both in animal models and in humans, including in the pediatric population. In this review, we summarize over 200 articles on the topic, most of which were identified objectively using reproducible online search terms in PubMed. Although these studies differ in terms of methodology and detailed outcomes; overall, recent research describes a common phenotype of excessive daytime sleepiness, nighttime sleep fragmentation, insomnia, and electroencephalography spectral changes after TBI. Given the heterogeneity of the human disease phenotype, rigorous translation of animal models to the human condition is critical to our understanding of the mechanisms and of the temporal course of sleep-wake disturbances after injury. Arguably, this is most effectively accomplished when animal and human studies are performed by the same or collaborating research programs. Given the number of symptoms associated with TBI that are intimately related to, or directly stem from sleep dysfunction, sleep-wake disorders represent an important area in which mechanistic-based therapies may substantially impact recovery after TBI.

Light, sleep and circadian rhythms in older adults with Alzheimer's disease and related dementias

Alzheimer's disease and related dementias (ADRD) can cause sleep and behavioral problems that are problematic for ADRD patients and their family caregivers. Light therapy has shown promise as a nonpharmacological treatment, and preliminary studies demonstrate that timed light exposure can consolidate and improve nighttime sleep efficiency, increase daytime wakefulness and reduce evening agitation without the adverse effects of pharmacological solutions. Compliance with light treatment and the accurate measurement of light exposures during treatment, however, have presented barriers for the adoption of light therapy for ADRD. Recent research showing that the circadian system is maximally sensitive to short-wavelength light opens the way for the potential application of lower, more-targeted light intensities to maximize compliance and individualize light dose/timing in therapeutic settings.

Sleep, Depression, and Fatigue in Late Postpartum

PURPOSE

To study the relation of infant characteristics and home environment on maternal sleep, depression, and fatigue in late postpartum.

STUDY DESIGN AND METHODS

Forty-two healthy mother-infant dyads completed a home-based study at infant age 32 weeks. Maternal measures included Patient Reported Outcomes Measurement Information System (PROMIS) sleep and wake disturbance, depression, and fatigue scales. Home regularity was assessed using the Confusion, Hubbub, and Order Scale (CHAOS). Infant sleep and regulation were measured respectively by the Brief Infant Sleep Questionnaire (BISQ) and Infant-Toddler Symptom Checklist (ITSC).

RESULTS

Significant correlations among maternal sleep and wake disturbance, fatigue, and depression were detected (r = .519 to .746, p < .01), but not with infant variables. Home regularity was significantly related with maternal variables (r = .597 to .653, p < .01).

CLINICAL IMPLICATIONS

Regularity of the home environment appears to contribute to maternal sleep, depression, and fatigue. Implications for intervention include establishment of daily routines and household management to improve regularity and consequently improve maternal outcomes.

The Relationship Between Sleep-Wake Cycle Disturbance and Trajectory of Cognitive Recovery During Acute Traumatic Brain Injury

OBJECTIVE

Following traumatic brain injury, both sleep dysfunction and cognitive impairment are common. Unfortunately, little is known regarding the potential associations between these 2 symptoms during acute recovery. This study sought to prospectively examine the relationship between ratings of sleep dysfunction and serial cognitive assessments among traumatic brain injury acute neurorehabilitation admissions.

METHODS

Participants were consecutive admissions to a free-standing rehabilitation hospital following moderate to severe traumatic brain injury (Median Emergency Department Glasgow Coma Scale = 7). Participants were assessed for sleep-wake cycle disturbance (SWCD) and cognitive functioning at admission and with subsequent weekly examinations. Participants were grouped on the basis of presence (SWCD+) or absence (SWCD-) of sleep dysfunction for each examination; groups were equivalent on demographic and injury variables. Individual Growth Curve modeling was used to examine course of Cognitive Test for Delirium performance across examinations.

RESULTS

Individual Growth Curve modeling revealed a significant interaction between examination number (ie, time) and SWCD group (β = -4.03, P < .001) on total Cognitive Test for Delirium score. The SWCD+ ratings on later examinations were predicted to result in lower Cognitive Test for Delirium scores and greater cognitive impairment over time.

CONCLUSIONS

This study has implications for improving neurorehabilitation treatment, as targeting sleep dysfunction for early intervention may facilitate cognitive recovery.

Sleep/awake status throughout the night and circadian motor activity patterns in older nursing-home residents with or without dementia, and older community-dwelling people without dementia

BACKGROUND

Sleep disturbances are commonly observed in older nursing home residents, mainly in combination with dementia. However, sleep-associated circadian motor activity patterns have not been thoroughly investigated in Japanese nursing homes. The present study aimed to respectively clarify the effect of community living and the presence of dementia on sleep disturbances and interrupted activity rhythm of older nursing-home residents with or without dementia and older community-dwelling people without dementia.

METHODS

Actigraph devices worn on the participants' non-dominant wrists for seven days were used to collect objective measurements of the sleep/awake status throughout the night and the circadian motor activity patterns. The presence of dementia was assessed by a trained medical doctor using the residents' records and the Clinical Dementia Rating (CDR). The functional capacity of the participants was determined using the Barthel Index (BI).

RESULTS

Fifty-one older people in Akita prefecture were included in the current study, consisting of 17 residents with dementia (mean age: 82.2 years), 17 residents without dementia (84.5 years), and 17 community-dwelling people (83.6 years). The results showed that older nursing-home residents with dementia had significantly a lower rate of sleep efficiency and a longer awake time throughout the night than the other groups. Older nursing-home residents with and without dementia had more fragmented rhythm than community-dwelling people without dementia.

CONCLUSION

These results provide evidence of poor sleep/awake status throughout the night and interrupted circadian activity rhythms in nursing-home residents with and without dementia. However, further studies performed according to dementia classifications are needed.

Control of the Cutaneous Circulation by the Central Nervous System

The central nervous system (CNS), via its control of sympathetic outflow, regulates blood flow to the acral cutaneous beds (containing arteriovenous anastomoses) as part of the homeostatic thermoregulatory process, as part of the febrile response, and as part of cognitive-emotional processes associated with purposeful interactions with the external environment, including those initiated by salient or threatening events (we go pale with fright). Inputs to the CNS for the thermoregulatory process include cutaneous sensory neurons, and neurons in the preoptic area sensitive to the temperature of the blood in the internal carotid artery. Inputs for cognitive-emotional control from the exteroceptive sense organs (touch, vision, sound, smell, etc.) are integrated in forebrain centers including the amygdala. Psychoactive drugs have major effects on the acral cutaneous circulation. Interoceptors, chemoreceptors more than baroreceptors, also influence cutaneous sympathetic outflow. A major advance has been the discovery of a lower brainstem control center in the rostral medullary raphé, regulating outflow to both brown adipose tissue (BAT) and to the acral cutaneous beds. Neurons in the medullary raphé, via their descending axonal projections, increase the discharge of spinal sympathetic preganglionic neurons controlling the cutaneous vasculature, utilizing glutamate, and serotonin as neurotransmitters. Present evidence suggests that both thermoregulatory and cognitive-emotional control of the cutaneous beds from preoptic, hypothalamic, and forebrain centers is channeled via the medullary raphé. Future studies will no doubt further unravel the details of neurotransmitter pathways connecting these rostral control centers with the medullary raphé, and those operative within the raphé itself. © 2016 American Physiological Society. Compr Physiol 6:1161-1197, 2016.

Circadian rhythms and attention deficit hyperactivity disorder: The what, the when and the why

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental condition characterised by impulsivity, inattention and hyperactivity. Aside from these core psychopathologies, sleep disturbances are found to be highly comorbid with ADHD, and indeed dysregulated sleep may contribute to some of the symptoms of the disorder. It is not clear how sleep disturbances come to be so common in ADHD, but one putative mechanism is through the circadian timekeeping system. This system underpins the generation of near 24-hour rhythms in a host of physiological, behavioural and psychological parameters, and is a key determinant of the sleep/wake cycle. In this paper we review the evidence for sleep and circadian rhythm disturbance in ADHD, examine the possible mechanistic links between these factors and the disorder and discuss future directions through which the circadian clock can be targetted for ADHD symptom relief.

Chronobesity: role of the circadian system in the obesity epidemic

Although obesity is considered to result from an imbalance between energy uptake and energy expenditure, the strategy of dietary changes and physical exercise has failed to tackle the global obesity epidemic. In search of alternative and more adequate treatment options, research has aimed at further unravelling the mechanisms underlying this excessive weight gain. While numerous studies are focusing on the neuroendocrine alterations that occur after bariatric Roux-en-Y gastric bypass surgery, an increasing amount of chronobiological studies have started to raise awareness concerning the pivotal role of the circadian system in the development and exacerbation of obesity. This internal timekeeping mechanism rhythmically regulates metabolic and physiological processes in order to meet the fluctuating demands in energy use and supply throughout the 24-h day. This review elaborates on the extensive bidirectional interaction between the circadian system and metabolism and explains how disruption of body clocks by means of shift work, frequent time zone travelling or non-stop consumption of calorie-dense foods can evoke detrimental metabolic alterations that contribute to obesity. Altering the body's circadian rhythms by means of time-related dietary approaches (chrononutrition) or pharmacological substances (chronobiotics) may therefore represent a novel and interesting way to prevent or treat obesity and associated comorbidities.

Bedtime Variability and Metabolic Health in Midlife Women: The SWAN Sleep Study

STUDY OBJECTIVES

Circadian misalignment, as seen in shift workers, can disrupt metabolic processes. Associations between sleep timing in nonshift workers and metabolic health are unknown. We examined sleep timing and indices of metabolic health in a community sample of midlife women.

METHODS

Caucasian (n = 161), African American (n = 121) and Chinese (n = 56) non-shift-working women aged 48-58 y who were not taking insulin-related medications, participated in the Study of Women's Health Across the Nation (SWAN) Sleep Study and were subsequently examined approximately 5.39 (standard deviation = 0.71) y later. Daily diary-reported bedtimes were used to calculate four measures of sleep timing: mean bedtime, bedtime variability, bedtime delay and bedtime advance. Body mass index (BMI) and insulin resistance (homeostatic model assessment-insulin resistance, HOMA-IR) were measured at two time points. Linear regressions evaluated whether sleep timing was associated with BMI and HOMA-IR cross-sectionally and prospectively.

RESULTS

In cross-sectional models, greater variability in bedtime and greater bedtime delay were associated with higher HOMA-IR (β = 0.128; P = 0.007, and β = 0.110; P = 0.013, respectively) and greater bedtime advance was associated with higher BMI (β = 0.095; P = 0.047). Prospectively, greater bedtime delay predicted increased HOMA-IR at Time 2 (β = 0.152; P = 0.003). Results were partially explained by shifted sleep timing on weekends.

CONCLUSION

Frequent shifts in sleep timing may be related to metabolic health among non-shift working midlife women.

COMMENTARY

A commentary on this article appears in this issue on page 269.

Disrupted Sleep: From Molecules to Cognition

Although the functions of sleep remain to be fully elucidated, it is clear that there are far-reaching effects of its disruption, whether by curtailment for a single night, by a few hours each night over a long period, or by disruption in sleep continuity. Epidemiological and experimental studies of these different forms of sleep disruption show deranged physiology from subcellular levels to complex affective behavior. In keeping with the multifaceted influence of sleep on health and well-being, we illustrate how the duration of sleep, its timing, and continuity can affect cellular ultrastructure, gene expression, metabolic and hormone regulation, mood, and vigilance. Recent brain imaging studies provide some clues on mechanisms underlying the most common cause of disrupted sleep (insomnia). These insights should ultimately result in adequate interventions to prevent and treat sleep disruption because of their high relevance to our most prevalent health problems.

SIGNIFICANCE STATEMENT

Disruption of the duration, timing, and continuity of sleep affects cellular ultrastructure, gene expression, appetite regulation, hormone production, vigilance, and reward functions.

The rest-activity rhythm and physical activity in early-onset dementia

BACKGROUND

A substantial part of elderly persons with dementia show rest-activity rhythm disturbances. The rest-activity rhythm is important to study in people with early-onset dementia (EOD) for rest-activity rhythm disturbances are predictive of institutionalization, and caregivers of young patients suffer from high distress.

OBJECTIVE

The aim of this study was to study (1) whether EOD patients have more rest-activity rhythm disturbances compared with cognitively intact adults; and (2) which factors contribute to a disturbed rhythm.

METHODS

We included 61 patients with EOD [mean age 61.9 (4.9) y, 41 (67%) men] and 68 cognitively intact adults [mean age 61.6 (4.5) y, 28 (41%) men]. Rest-activity rhythm was assessed by actigraphy.

RESULTS

EOD patients tended to have higher intradaily variability [0.46 (0.16) and 0.39 (0.10), P=0.03]. EOD patients also lay for a longer time in bed [time in bed: 08:49 (0:51) h and 08:07 (0:47) h, P<0.001] and needed more time to fall asleep [sleep onset latency: 23 (22) min and 15 (15) min, P=0.02]. Disturbances in the rest-activity rhythm were predicted by a low level of physical activity, use of antidepressants and central nervous system neurological medications, and being male.

CONCLUSIONS

EOD patients showed more variability in the rest-activity rhythm compared with cognitively intact adults. The main predictor for rest-activity rhythm disturbances was a low level of physical activity.

Nonstandard working schedules and health: the systematic search for a comprehensive model

BACKGROUND

Theoretical models on shift work fall short of describing relevant health-related pathways associated with the broader concept of nonstandard working schedules. Shift work models neither combine relevant working time characteristics applicable to nonstandard schedules nor include the role of rest periods and recovery in the development of health complaints. Therefore, this paper aimed to develop a comprehensive model on nonstandard working schedules to address these shortcomings.

METHODS

A literature review was conducted using a systematic search and selection process. Two searches were performed: one associating the working time characteristics time-of-day and working time duration with health and one associating recovery after work with health. Data extracted from the models were used to develop a comprehensive model on nonstandard working schedules and health.

RESULTS

For models on the working time characteristics, the search strategy yielded 3044 references, of which 26 met the inclusion criteria that contained 22 distinctive models. For models on recovery after work, the search strategy yielded 896 references, of which seven met the inclusion criteria containing seven distinctive models. Of the models on the working time characteristics, three combined time-of-day with working time duration, 18 were on time-of-day (i.e. shift work), and one was on working time duration. The model developed in the paper has a comprehensive approach to working hours and other work-related risk factors and proposes that they should be balanced by positive non-work factors to maintain health. Physiological processes leading to health complaints are circadian disruption, sleep deprivation, and activation that should be counterbalanced by (re-)entrainment, restorative sleep, and recovery, respectively, to maintain health.

CONCLUSIONS

A comprehensive model on nonstandard working schedules and health was developed. The model proposes that work and non-work as well as their associated physiological processes need to be balanced to maintain good health. The model gives researchers a useful overview over the various risk factors and pathways associated with health that should be considered when studying any form of nonstandard working schedule.

Effectiveness of internet-supported cognitive behavioral and chronobiological interventions and effect moderation by insomnia subtype: study protocol of a randomized controlled trial

BACKGROUND

DSM-V criteria for insomnia disorder are met by 6 to 10% of the adult population. Insomnia has severe consequences for health and society. One of the most common treatments provided by primary caregivers is pharmacological treatment, which is far from optimal and has not been recommended since a 2005 consensus report of the National Institutes of Health. The recommended treatment is Cognitive Behavioral Therapy for Insomnia. Effectiveness, however, is still limited. Only a few studies have evaluated the effectiveness of chronobiological treatments, including the timed application of bright light, physical activity and body warming. Another opportunity for optimization of treatment is based on the idea that the people suffering from insomnia most likely represent a heterogeneous mix of subtypes, with different underlying causes and expected treatment responses. The present study aims to evaluate the possibility for optimizing insomnia treatment along the principles of personalized and stratified medicine. It evaluates the following: 1. The relative effectiveness of internet-supported cognitive behavioral therapy, bright light, physical activity and body warming; 2. Whether the effectiveness of internet-supported cognitive behavioral therapy for insomnia can be augmented by simultaneous or prior application of bright light, physical activity and body warming; and 3. Whether the effectiveness of the interventions and their combination are moderated by the insomnia subtype.

METHODS/DESIGN

In a repeated measures, placebo-controlled, randomized clinical trial that included 160 people diagnosed with insomnia disorder, we are evaluating the relative effectiveness of 4 intervention weeks. Primary outcome is subjective sleep efficiency, quantified using a sleep diary. Secondary outcomes include other complaints of sleep and daytime functioning, health-related cost estimates and actigraphic objective sleep estimates. Compliance will be monitored both subjectively and objectively using activity, light and temperature sensors. Insomnia subtypes will be assessed using questionnaires. Mixed effect models will be used to evaluate intervention effects and moderation by insomnia subtype ratings.

DISCUSSION

The current study addresses multiple opportunities to optimize and personalize treatment of insomnia disorder.

TRIAL REGISTRATION

Netherlands National Trial Register NTR4010, 4 June 2013.