Development of Late Circadian Preference: Sleep Timing From Childhood to Late Adolescence

OBJECTIVES

To assess differences relating to circadian preference in objectively measured sleep patterns from childhood to adolescence over a 9-year period. We hypothesized there is developmental continuity in sleep timing and duration according to circadian preference.

STUDY DESIGN

Young participants (N = 111, 65% girls) from a community-based birth cohort underwent sleep actigraphy at mean ages 8.1 (SD = 0.3), 12.3 (SD = 0.5), and 16.9 (SD = 0.1) years. A short version of Morningness-Eveningness Questionnaire was administered in late adolescence. At each follow-up, sleep midpoint, duration, wake after sleep onset, sleep efficiency, and weekend catch-up sleep were compared between those reporting morning, intermediate, and evening preferences in late adolescence.

RESULTS

Mixed model analyses indicated that sleep timing was significantly earlier among morning types compared with evening types at all ages (P values < .04). The mean differences in sleep midpoint between morning and evening types increased from a mean of 19 minutes (age 8), 36 minutes (age 12), to 89 minutes (age 17). The largest change occurred from age 12 to 17 years. Sleep duration, wake after sleep onset, sleep efficiency, and catch-up sleep did not differ according to circadian preference.

CONCLUSIONS

This study found significant continuity in sleep timing from childhood to adolescence over 9 years, indicating that late circadian preference reported in late adolescence begins to manifest in middle childhood. Further studies are needed to establish whether sleep timing has its origins at an even earlier age.

Physical activity levels in adults and older adults 3-4 years after pedometer-based walking interventions: Long-term follow-up of participants from two randomised controlled trials in UK primary care

BACKGROUND

Physical inactivity is an important cause of noncommunicable diseases. Interventions can increase short-term physical activity (PA), but health benefits require maintenance. Few interventions have evaluated PA objectively beyond 12 months. We followed up two pedometer interventions with positive 12-month effects to examine objective PA levels at 3-4 years.

METHODS AND FINDINGS

Long-term follow-up of two completed trials: Pedometer And Consultation Evaluation-UP (PACE-UP) 3-arm (postal, nurse support, control) at 3 years and Pedometer Accelerometer Consultation Evaluation-Lift (PACE-Lift) 2-arm (nurse support, control) at 4 years post-baseline. Randomly selected patients from 10 United Kingdom primary care practices were recruited (PACE-UP: 45-75 years, PACE-Lift: 60-75 years). Intervention arms received 12-week walking programmes (pedometer, handbooks, PA diaries) postally (PACE-UP) or with nurse support (PACE-UP, PACE-Lift). Main outcomes were changes in 7-day accelerometer average daily step counts and weekly time in moderate-to-vigorous PA (MVPA) in ≥10-minute bouts in intervention versus control groups, between baseline and 3 years (PACE-UP) and 4 years (PACE-Lift). PACE-UP 3-year follow-up was 67% (681/1,023) (mean age: 59, 64% female), and PACE-Lift 4-year follow-up was 76% (225/298) (mean age: 67, 53% female). PACE-UP 3-year intervention versus control comparisons were as follows: additional steps/day postal +627 (95% CI: 198-1,056), p = 0.004, nurse +670 (95% CI: 237-1,102), p = 0.002; total weekly MVPA in bouts (minutes/week) postal +28 (95% CI: 7-49), p = 0.009, nurse +24 (95% CI: 3-45), p = 0.03. PACE-Lift 4-year intervention versus control comparisons were: +407 (95% CI: -177-992), p = 0.17 steps/day, and +32 (95% CI: 5-60), p = 0.02 minutes/week MVPA in bouts. Neither trial showed sedentary or wear-time differences. Main study limitation was incomplete follow-up; however, results were robust to missing data sensitivity analyses.

CONCLUSIONS

Intervention participants followed up from both trials demonstrated higher levels of objectively measured PA at 3-4 years than controls, similar to previously reported 12-month trial effects. Pedometer interventions, delivered by post or with nurse support, can help address the public health physical inactivity challenge.

TRIAL REGISTRATIONS

PACE-UP isrctn.com ISRCTN98538934; PACE-Lift isrctn.com ISRCTN42122561.

Assessment of the Fitbit Charge 2 for monitoring heart rate

Fitness trackers are devices or applications for monitoring and tracking fitness-related metrics such as distance walked or run, calorie consumption, quality of sleep and heart rate. Since accurate heart rate monitoring is essential in fitness training, the objective of this study was to assess the accuracy and precision of the Fitbit Charge 2 for measuring heart rate with respect to a gold standard electrocardiograph. Fifteen healthy participants were asked to ride a stationary bike for 10 minutes and their heart rate was simultaneously recorded from each device. Results showed that the Fitbit Charge 2 underestimates the heart rate. Although the mean bias in measuring heart rate was a modest -5.9 bpm (95% CI: -6.1 to -5.6 bpm), the limits of agreement, which indicate the precision of individual measurements, between the Fitbit Charge 2 and criterion measure were wide (+16.8 to -28.5 bpm) indicating that an individual heart rate measure could plausibly be underestimated by almost 30 bpm.

The feasibility of using actigraphy to characterize sleep in Rett syndrome

BACKGROUND

Rett syndrome (RTT) is a neurodevelopmental disorder primarily caused by mutations in the MECP2 gene. Sleep problems are reported by the majority of caregivers of individuals with RTT.

METHODS

The present study aimed to replicate and extend previous work about the feasibility of measuring sleep with an actigraph device in a sample of girls with clinically diagnosed RTT (N = 13, mean age = 9 years, 5 months). Participants wore an actigraph device day and night for seven consecutive days. Materials also included a parent-completed sleep diary to measure bedtime, duration of nighttime sleep, and daytime sleep, and the Child Sleep Habit's Questionnaire (CSHQ).

RESULTS

The means for the sample as measured by actigraphy were 492.3 min (SD = 47.3) of total night sleep (TNS), 76.0% (SD = 6.7) sleep efficiency, 86.0 min (SD = 34.2) of wake after sleep onset, and 46.1 min (50.8) of sleep when parents reported a nap occurring. Parents reported 589.7 min (SD = 53.6) of TNS, 15.9 min (SD = 12.0) of WASO, and 93.6 min (SD = 66.8) of daytime sleep according to sleep diaries, with all parents reporting at least one nap during the week. Relations were found between sleep characteristics and seizure status and CSHQ total scores. No age-related changes were observed for any sleep characteristic, regardless of collection method. Five of nine participants above the cutoff score on the CSHQ indicate the need for further evaluation for a sleep disorder.

CONCLUSIONS

Overall, actigraphy was feasible in this community-based sample of girls with RTT. The results replicated some aspects of previous studies of sleep in RTT (e.g., no age-related changes in total nighttime sleep or efficiency). Some participants met the American Academy of Sleep Medicine guidelines for recommended total sleep time, with others showing too much or too little sleep. Each of the three methods for describing sleep presented its own advantages and challenges. Future work should be prospectively designed, validate the use of actigraphy in this population, and include a typically developing comparison sample to improve the precision of our understanding of sleep in RTT.

Individual differences in compliance and agreement for sleep logs and wrist actigraphy: A longitudinal study of naturalistic sleep in healthy adults

There is extensive laboratory research studying the effects of acute sleep deprivation on biological and cognitive functions, yet much less is known about naturalistic patterns of sleep loss and the potential impact on daily or weekly functioning of an individual. Longitudinal studies are needed to advance our understanding of relationships between naturalistic sleep and fluctuations in human health and performance, but it is first necessary to understand the efficacy of current tools for long-term sleep monitoring. The present study used wrist actigraphy and sleep log diaries to obtain daily measurements of sleep from 30 healthy adults for up to 16 consecutive weeks. We used non-parametric Bland-Altman analysis and correlation coefficients to calculate agreement between subjectively and objectively measured variables including sleep onset time, sleep offset time, sleep onset latency, number of awakenings, the amount of wake time after sleep onset, and total sleep time. We also examined compliance data on the submission of daily sleep logs according to the experimental protocol. Overall, we found strong agreement for sleep onset and sleep offset times, but relatively poor agreement for variables related to wakefulness including sleep onset latency, awakenings, and wake after sleep onset. Compliance tended to decrease significantly over time according to a linear function, but there were substantial individual differences in overall compliance rates. There were also individual differences in agreement that could be explained, in part, by differences in compliance. Individuals who were consistently more compliant over time also tended to show the best agreement and lower scores on behavioral avoidance scale (BIS). Our results provide evidence for convergent validity in measuring sleep onset and sleep offset with wrist actigraphy and sleep logs, and we conclude by proposing an analysis method to mitigate the impact of non-compliance and measurement errors when the two methods provide discrepant estimates.

Which Sleep Health Characteristics Predict All-Cause Mortality in Older Men? An Application of Flexible Multivariable Approaches

Study Objectives

Sleep is multidimensional, with domains including duration, timing, continuity, regularity, rhythmicity, quality, and sleepiness/alertness. Individual sleep characteristics representing these domains are known to predict health outcomes. However, most studies consider sleep characteristics in isolation, resulting in an incomplete understanding of which sleep characteristics are the strongest predictors of health outcomes. We applied three multivariable approaches to robustly determine which sleep characteristics increase mortality risk in the osteoporotic fractures in men sleep study.

Methods

In total, 2,887 men (mean 76.3 years) completed relevant assessments and were followed for up to 11 years. One actigraphy or self-reported sleep characteristic was selected to represent each of seven sleep domains. Multivariable Cox models, survival trees, and random survival forests were applied to determine which sleep characteristics increase mortality risk.

Results

Rhythmicity (actigraphy pseudo-F statistic) and continuity (actigraphy minutes awake after sleep onset) were the most robust sleep predictors across models. In a multivariable Cox model, lower rhythmicity (hazard ratio, HR [95%CI] =1.12 [1.04, 1.22]) and lower continuity (1.16 [1.08, 1.24]) were the strongest sleep predictors. In the random survival forest, rhythmicity and continuity were the most important individual sleep characteristics (ranked as the sixth and eighth most important among 43 possible sleep and non-sleep predictors); moreover, the predictive importance of all sleep information considered simultaneously followed only age, cognition, and cardiovascular disease.

Conclusions

Research within a multidimensional sleep health framework can jumpstart future research on causal pathways linking sleep and health, new interventions that target specific sleep health profiles, and improved sleep screening for adverse health outcomes.

Sleep Quantity and Quality of Ontario Wildland Firefighters Across a Low-Hazard Fire Season

OBJECTIVE

The aim of the study was to assess the sleep quality, quantity, and fatigue levels of Canadian wildland firefighters while on deployment.

METHODS

Objective and subjective sleep and fatigue measures were collected using actigraphy and questionnaires during non-fire (Base) and fire (Initial Attack and Project) deployments.

RESULTS

Suboptimal sleep quality and quantity were more frequently observed during high-intensity, Initial Attack fire deployments. Suboptimal sleep was also exhibited during non-fire (Base) work periods, which increases the risk of prefire deployment sleep debt. Self-reported, morning fatigue scores were low-to-moderate and highest for Initial Attack fire deployments.

CONCLUSIONS

The study highlights the incidence of suboptimal sleep patterns in wildland firefighters during non-fire and fire suppression work periods. These results have implications for the health and safety practices of firefighters given the link between sleep and fatigue, in a characteristically hazardous occupation.

Sleep Quality in Adolescents With Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME)

STUDY OBJECTIVES

Little is known about the type and severity of sleep disturbances in the pediatric chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) population, compared with healthy adolescents. Using a range of objective and subjective measures, the aim of this study was to investigate sleep quality, the relationship between objective and subjective measures of sleep quality, and their associations with anxiety in adolescents with CFS/ME compared with healthy controls.

METHODS

Twenty-one adolescents with CFS/ME aged 13 to 18 years (mean age 15.57 ± 1.40), and 145 healthy adolescents aged 13 to 18 years (mean age 16.2 ± 1.00) wore actigraphy watches continuously for 2 weeks to collect a number of objective sleep variables. The Pittsburgh Sleep Quality Index was used to obtain a subjective measure of sleep quality. Anxiety was measured by the Spence Children's Anxiety scale.

RESULTS

On average over the 2-week period, adolescents with CFS/ME were found to have (1) significantly longer objective sleep onset latency, time in bed, total sleep time, and a later rise time (all P < .005), and (2) significantly poorer subjective sleep quality (P < .001), compared with healthy adolescents. The CFS/ME patient group displayed higher levels of anxiety (P < .05), and in both groups, higher levels of anxiety were significantly related to poorer subjective sleep quality (P < .001).

CONCLUSIONS

This study provides objective and subjective evidence of sleep disturbance in adolescents with CFS/ME compared with healthy adolescent controls.

Actigraphy scoring for sleep outcome measures in chronic obstructive pulmonary disease

BACKGROUND

Actigraphy is commonly used to measure sleep outcomes so that sleep can be measured conveniently at home over multiple nights. Actigraphy has been validated in people with sleep disturbances; however, the validity of scoring settings in people with chronic medical illnesses such as chronic obstructive pulmonary disease remains unclear. The purpose of this secondary analysis was to compare actigraphy-customized scoring settings with polysomnography (PSG) for the measurement of sleep outcomes in people with chronic obstructive pulmonary disease who have insomnia.

METHODS

Participants underwent overnight sleep assessment simultaneously by PSG and actigraphy at the University of Illinois of Chicago Sleep Science Center. Fifty participants (35 men and 15 women) with mild-to-severe chronic obstructive pulmonary disease and co-existing insomnia were included in the analysis. Sleep onset latency, total sleep time (TST), wake after sleep onset (WASO), and sleep efficiency (SE) were calculated independently from data derived from PSG and actigraphy. Actigraphy sleep outcome scores obtained at the default setting and several customized actigraphy settings were compared to the scored PSG results.

RESULTS

Although no single setting was optimal for all sleep outcomes, the combination of 10 consecutive immobile minutes for sleep onset or end and an activity threshold of 10 worked well. Actigraphy overestimated TST and SE and underestimated WASO, but there was no difference in variance between PSG and actigraphy in TST and SE when the 10 × 10 combination was used. As the average TST and SE increased, the agreement between PSG and actigraphy appeared to increase, and as the average WASO decreased, the agreement between PSG and actigraphy appeared to increase.

CONCLUSION

Results support the conclusion that the default actigraphy settings may not be optimal for people with chronic obstructive pulmonary disease and co-existing insomnia.

The Effect of Dogs on Human Sleep in the Home Sleep Environment

OBJECTIVE

To objectively assess whether a dog in the bedroom or bed disturbs sleep.

PARTICIPANTS AND METHODS

From August 1, 2015, through December 31, 2015, we evaluated the sleep of humans and dogs occupying the same bedroom to determine whether this arrangement was conducive to sleep. The study included 40 healthy adults without sleep disorders and their dogs (no dogs <6 months old). Each participant wore an accelerometer and their dog a validated dog accelerometer for 7 nights.

RESULTS

The mean ± SD age of the participants (88% women) was 44±14 years and body mass index was 25±6. The mean ± SD age of the dogs was 5±3 years and weight was 15±13 kg. Mean ± SD actigraphy data showed 475±101 minutes in bed, 404±99 minutes total sleep time, 81%±7% sleep efficiency, and 71±35 minutes wake time after sleep onset. The dogs' accelerometer activity during the corresponding human sleep period was characterized as mean ± SD minutes at rest, active, and at play of 413±102, 62±43, and 2±4. The dogs had mean ± SD 85%±15% sleep efficiency. Human sleep efficiency was lower if the dog was on the bed as opposed to simply in the room (P=.003).

CONCLUSION

Humans with a single dog in their bedroom maintained good sleep efficiency; however, the dog's position on/off the bed made a difference. A dog's presence in the bedroom may not be disruptive to human sleep, as was previously suspected.

Personality and actigraphy-measured physical activity in older adults

Most studies on personality and physical activity have relied on self-report measures. This study examined the relation between Five Factor Model personality traits and objective physical activity in older adults. Sixty-nine participants (Mage = 80.2 years; SD = 7.1) wore the ActiGraph monitor for 7 days and completed the NEO Personality Inventory-3 First Half. Extraversion, Agreeableness, and Conscientiousness were associated with more moderate physical activity and more steps per day whereas Neuroticism was inversely related to these physical activity measures (βs > .20). The associations for Neuroticism and Conscientiousness were attenuated by approximately 20-40% when accounting for disease burden and body mass index but were essentially unchanged for Extraversion and Agreeableness. These findings confirm self-report evidence that personality traits are associated with physical activity levels in older adults. (PsycINFO Database Record

Utility of the Fitbit Flex to evaluate sleep in major depressive disorder: A comparison against polysomnography and wrist-worn actigraphy

BACKGROUND

Sleep disturbance is a common and important component of affective illness. Fitness activity trackers are emerging as alternative means to estimate sleep in psychiatric patients; however, their ability to quantify sleep in mood disorders has not been empirically evaluated. Thus, this study sought to evaluate the utility of the Fitbit Flex (FBF) to estimate sleep in patients with major depressive disorder (MDD) relative to gold standard polysomnography (PSG) and a widely-used actigraph (Actiwatch-2; AW-2).

METHODS

Twenty-one patients with unipolar MDD wore the FBF and AW-2 during in-laboratory PSG. Bland-Altman analysis compared sleep variables among devices. Epoch-by-epoch analysis further evaluated sensitivity, specificity, and accuracy for the FBF and AW-2 relative to PSG.

RESULTS

The FBF demonstrated significant limitations in quantifying sleep and wake, relative to PSG. In the normal setting, the FBF significantly overestimated sleep time and efficiency, and displayed poor ability to correctly identify wake epochs (i.e. low specificity). In the sensitive setting, the FBF significantly underestimated sleep time and efficiency relative to PSG. Performance characteristics of the FBF were more similar to the AW-2 in the normal compared to sensitive setting.

LIMITATIONS

Participants were young to middle aged and predominantly female, which may limit generalizability of findings. Study design also precluded ability to assess longitudinal performance of FBF.

CONCLUSIONS

The FBF is not an adequate substitute for PSG when quantifying sleep in MDD, and the settings of the device sizably impact its performance relative to PSG and other standard actigraphs. The limitations and capabilities of the FBF should be carefully considered prior to clinical and research implementation.

Multiscale adaptive analysis of circadian rhythms and intradaily variability: Application to actigraphy time series in acute insomnia subjects

Circadian rhythms become less dominant and less regular with chronic-degenerative disease, such that to accurately assess these pathological conditions it is important to quantify not only periodic characteristics but also more irregular aspects of the corresponding time series. Novel data-adaptive techniques, such as singular spectrum analysis (SSA), allow for the decomposition of experimental time series, in a model-free way, into a trend, quasiperiodic components and noise fluctuations. We compared SSA with the traditional techniques of cosinor analysis and intradaily variability using 1-week continuous actigraphy data in young adults with acute insomnia and healthy age-matched controls. The findings suggest a small but significant delay in circadian components in the subjects with acute insomnia, i.e. a larger acrophase, and alterations in the day-to-day variability of acrophase and amplitude. The power of the ultradian components follows a fractal 1/f power law for controls, whereas for those with acute insomnia this power law breaks down because of an increased variability at the 90min time scale, reminiscent of Kleitman’s basic rest-activity (BRAC) cycles. This suggests that for healthy sleepers attention and activity can be sustained at whatever time scale required by circumstances, whereas for those with acute insomnia this capacity may be impaired and these individuals need to rest or switch activities in order to stay focused. Traditional methods of circadian rhythm analysis are unable to detect the more subtle effects of day-to-day variability and ultradian rhythm fragmentation at the specific 90min time scale.

Short-term sleep deprivation leads to decreased systemic redox metabolites and altered epigenetic status

Sleep is critical for repair as well as the rejuvenation processes in the body and many of these functions are regulated via underlying cellular metabolic homeostasis. Changes in sleep pattern are reported to alter such metabolic function resulting in altered disease susceptibility or behavior. Here, we measured the extent to which overnight total sleep deprivation (SD) in young adult humans can influence systemic (plasma-derived) redox-metabolism including the major antioxidant, glutathione as well as DNA methylation levels. Nineteen participants (n = 19, μ age = 21, SD = 3.09) underwent morning testing before and after overnight total SD. Biochemical measures before and after SD revealed that glutathione, ATP, cysteine, and homocysteine levels were significantly reduced following one night of sleep deprivation (all p’s < 0.01). Parallel to the well-recognized fact that sleep deprivation (maintaining wakefulness) uses up metabolic reserves, we observed that morning cortisol levels were blunted after sleep deprivation. There were no significant correlations between self-reported or actigraphy-measured sleep and the biochemical measurements, strongly indicating that prior sleep behavior did not have any direct influence on the biochemical measures taken at baseline or after sleep deprivation. Results from the current investigation supports the previous literature implicating the induction of oxidative stress and ATP depletion with sleep deprivation. Furthermore, such altered antioxidant status can also induce downstream epigenetic changes. Although we did not measure the specific genes that were altered under the influence of such sleep deprivation, such epigenetic changes could potentially contribute towards disease predisposition.

Feasibility of Continuous Actigraphy in Patients in a Medical Intensive Care Unit

BACKGROUND

Poor sleep and immobility are common in patients in the medical intensive care unit (MICU) and are associated with adverse outcomes. Interventions to promote sleep and mobilization in the MICU are gaining popularity, but feasible instruments to measure their effectiveness are lacking. Actigraphy may be useful for large-scale, continuous measurement of sleep and activity, but its feasibility in MICU patients has not been rigorously evaluated.

OBJECTIVE

To evaluate the feasibility of continuous actigraphy measurement in consecutive MICU patients.

METHODS

Wrist and ankle actigraphy data were collected for 48 hours in consenting MICU patients. Actigraphy-based measures of estimated sleep and activity were summarized by using descriptive statistics. Agreement between wrist and ankle measurements was evaluated using Cohen κ statistics (for sleep quantity) and intraclass correlation coefficients (for activity).

RESULTS

Overall, 35 of 48 (73%) eligible patients were enrolled, including 10 requiring mechanical ventilation. Of these patients, 34 (97%) completed the 48-hour actigraphy period; 20 (57%) found the devices comfortable. Wrist devices logged a mean (SD) of 33.4 (8.8) hours of estimated sleep (72% [19%] of recording period) and 19.6 (17.2) movements per 30-second epoch. Ankle devices recorded 43.2 (4.1) hours of estimated sleep (93% [7%] of recording period) and 5.1 (6.0) movements per 30 seconds.

CONCLUSIONS

Uninterrupted actigraphy is feasible and generally well tolerated by MICU patients and may be considered for future large-scale studies. Wrist and ankle actigraphy measurements of sleep and activity in this setting agree poorly and cannot be used interchangeably.

Sleep stage classification by non-contact vital signs indices using Doppler radar sensors

Disturbed sleep has become more common in recent years. To improve the quality of sleep, undergoing sleep observation has gained interest as a means to resolve possible problems. In this paper, we evaluate a non-restrictive and non-contact method for classifying real-time sleep stages and report on its potential applications. The proposed system measures heart rate (HR), heart rate variability (HRV), body movements, and respiratory signals of a sleeping person using two 24-GHz microwave radars placed beneath the mattress. We introduce a method that dynamically selects the window width of the moving average filter to extract the pulse waves from the radar output signals. The Pearson correlation coefficient between two HR measurements derived from the radars overnight, and the reference polysomnography was the average of 88.3% and the correlation coefficient for HRV parameters was the average of 71.2%. For identifying wake and sleep periods, the body-movement index reached sensitivity of 76.0%, and a specificity of 77.0% with 10 participants. Low-frequency (LF) components of HRV and the LF/HF ratio had a high degree of contribution and differed significantly across the three sleep stages (REM, LIGHT, and DEEP; p <; 0.01). In contrast, high-frequency (HF) components of HRV were not significantly different across the three sleep stages (p > 0.05). We applied a canonical discriminant analysis to identify wake or sleep periods and to classify the three sleep stages with leave-one-out cross validation. Classification accuracy was 66.4% for simply identifying wake and sleep, 57.1% for three stages (wake, REM, and NREM) and 34% for four stages (wake, REM, LIGHT, and DEEP). This is a novel system for measuring HRs, HRV, body movements, and respiratory intervals and for measuring high sensitivity pulse waves using two radar signals. It simplifies measurement of sleep stages and may be employed at nursing care facilities or by the general public to improve sleep quality.

Detection of Nocturnal Scratching Movements in Patients with Atopic Dermatitis Using Accelerometers and Recurrent Neural Networks

Atopic dermatitis is a chronic inflammatory skin condition affecting both children and adults and is associated with pruritus. A method for objectively quantifying nocturnal scratching events could aid in the development of therapies for atopic dermatitis and other pruritic disorders. High-resolution wrist actigraphy (three-dimensional accelerometer sensors sampled at 20 Hz) is a noninvasive method to record movement. This paper presents an algorithm to detect nocturnal scratching events based on actigraphy data. The twofold process consists of segmenting the data into "no motion," "single handed motion," and "both handed motion" followed by discriminating motion segments into scratching and other motion using a bidirectional recurrent neural network classifier. The performance was compared against manually scored infrared video data collected from 24 subjects (6 healthy controls and 18 atopic dermatitis patients) demonstrating an score of 0.68 and a rank correlation of 0.945. The algorithm clearly outperformed a published reference method based on wrist actigraphy ( score of 0.09 and a rank correlation of 0.466). The results suggest that scratching movements can be discriminated from other nocturnal movements accurately.

Effectiveness of Interventions for Promoting Objectively Measured Physical Activity of Adults With Type 2 Diabetes: A Systematic Review

BACKGROUND

Many people with type 2 diabetes (T2D) are sedentary despite strong recommendations of regular physical activity (PA). Objective measures of PA provide accurate reflection of daily PA level. The purpose of this review was to analyze studies used pedometers or accelerometers to determine the outcome of interventions promoted daily PA in people with T2D.

METHODS

An electronic literature search was conducted using the PubMed and CINAHL databases (2000-2016), with search terms: sedentary, diabetes, pedometer, physical activity, and accelerometer. Only peer-reviewed, randomized clinical trials (RCTs) that used objective measurement of daily PA level were included. All studies design, participant characteristics, intervention, and key findings were evaluated systematically and summarized.

RESULTS

A total of 15 RCTs were identified investigated objectively measured daily PA in people with T2D. A significant increase in PA was found following exercise consultation, behavioral/cognitive consultation, continuous glucose monitoring counseling, and motivational phone calls promoting PA. However, this increase in daily PA level was evident only during the intervention period.

CONCLUSIONS

Our systematic review of the literature indicated that a variety of interventions approaches were effective in increasing PA temporarily during the intervention period. Interventions that use objective methods in measuring PA and have long term improvement in overall PA are needed.

Impact of accelerometer and pedometer use on physical activity and glycaemic control in people with Type 2 diabetes: a systematic review and meta-analysis

BACKGROUND

Self-directed pedometer use increases physical activity levels in the general population; however, evidence of benefit for Type 2 diabetes is unclear and has not been systematically reviewed for accelerometers.

AIM

To examine the impact of using physical activity monitoring devices (pedometers and accelerometers) on free-living physical activity and HbA_1c levels in people with Type 2 diabetes.

METHODS

We conducted a systematic literature review. Bibliographic databases included Medline, Embase, Web of Science, CINAHL, SportDiscus and the Cochrane Central Register of Controlled Trials. We included controlled trials evaluating interventions based on the use of pedometers or accelerometers to promote physical activity in people with Type 2 diabetes. Primary outcomes were physical activity (min/week or steps) and HbA_1c [mmol/mol (%)]. Secondary outcomes were weight, blood pressure and lipid profile.

RESULTS

Twelve trials (1458 participants) were identified, of which nine studied pedometers and three accelerometers. Random-effects meta-analysis showed an overall increase in physical activity (standardized mean difference 0.57, 95% CI 0.24, 0.91) in the intervention groups. Accelerometers and pedometers produced a similar effect size. No significant differences were observed in HbA_1c , BMI, blood pressure or lipid profile.

CONCLUSIONS

People with Type 2 diabetes, provided with an accelerometer or pedometer, substantially increased their free-living physical activity. There is no evidence that monitor use alone improves HbA_1c or other clinical outcomes. Further trials are needed to compare the relative effects of activity monitors within differing complex interventions.

Automatic Human Movement Assessment With Switching Linear Dynamic System: Motion Segmentation and Motor Performance

Performance assessment of human movement is critical in diagnosis and motor-control rehabilitation. Recent developments in portable sensor technology enable clinicians to measure spatiotemporal aspects to aid in the neurological assessment. However, the extraction of quantitative information from such measurements is usually done manually through visual inspection. This paper presents a novel framework for automatic human movement assessment that executes segmentation and motor performance parameter extraction in time-series of measurements from a sequence of human movements. We use the elements of a Switching Linear Dynamic System model as building blocks to translate formal definitions and procedures from human movement analysis. Our approach provides a method for users with no expertise in signal processing to create models for movements using labeled dataset and later use it for automatic assessment. We validated our framework on preliminary tests involving six healthy adult subjects that executed common movements in functional tests and rehabilitation exercise sessions, such as sit-to-stand and lateral elevation of the arms and five elderly subjects, two of which with limited mobility, that executed the sit-to-stand movement. The proposed method worked on random motion sequences for the dual purpose of movement segmentation (accuracy of 72%-100%) and motor performance assessment (mean error of 0%-12%).

A novel approach using actigraphy to quantify the level of disruption of sleep by in-home polysomnography: the MrOS Sleep Study: Sleep disruption by polysomnography

BACKGROUND

The "first-night effect" of polysomnography (PSG) has been previously studied; however, the ability to quantify the sleep disruption level has been confounded with the use of PSG on all nights. We used actigraphy to quantify disruption level and examined characteristics associated with disruption.

METHODS

Totally, 778 older men (76.2 ± 5.4 years) from a population-based study at six US centers underwent one night of in-home PSG. Actigraphy was performed on the PSG night and three subsequent nights. Actigraphically measured total sleep time (TST), sleep efficiency (SE), wake after sleep onset (WASO), and sleep onset latency (SOL) from the PSG night and subsequent nights were compared. Linear regression models were used to examine the association of characteristics and sleep disruption.

RESULTS

On average, sleep on the PSG night was worse than the following night (p < 0.05, TST 21 ± 85 min less, SE 2.3 ± 11.3% less, WASO 4.9 ± 51.8 min more, SOL 6.6 ± 56.2 min more). Sleep on the PSG night was significantly worse than that two and three nights later. Characteristics associated with greater sleep disruption on the PSG night included older age, higher apnea-hypopnea index, worse neuromuscular function, and more depressive symptoms. Minorities and men with excessive daytime sleepiness slept somewhat better on the PSG night.

CONCLUSIONS

Among older men, there was sleep disruption on the PSG night, which may lead to sleep time underestimation. The increase of sleep on the night after the PSG suggests that data from the second monitoring may overestimate sleep.

From the midnight sun to the longest night: Sleep in Antarctica

Sleep disturbances are the main health complaints from personnel deployed in Antarctica. The current paper presents a systematic review of research findings on sleep disturbances in Antarctica. The available sources were divided in three categories: results based on questionnaire surveys or sleep logs, studies using actigraphy, and data from polysomnography results. Other areas relevant to the issue were also examined. These included chronobiology, since the changes in photoperiod have been known to affect circadian rhythms, mood disturbances, exercise, sleep and hypoxia, countermeasure investigations in Antarctica, and other locations lacking a normal photoperiod. Based on the combination of our reviewed sources and data outside the field of sleep studies, or from other geographical locations, we defined hypotheses to be confirmed or infirmed, which allowed to summarize a research agenda. Despite the scarcity of sleep research on the Antarctic continent, the present review pinpointed some consistent changes in sleep during the Antarctic winter, the common denominators being a circadian phase delay, poor subjective sleep quality, an increased sleep fragmentation, as well as a decrease in slow wave sleep. Similar changes, albeit less pronounced, were observed during summer. Additional multidisciplinary research is needed to elucidate the mechanisms behind these changes in sleep architecture, and to investigate interventions to improve the sleep quality of the men and women deployed in the Antarctic.

How Well Do Children with Cystic Fibrosis Sleep? An Actigraphic and Questionnaire-Based Study

OBJECTIVE

To measure sleep patterns and quality, objectively and subjectively, in clinically stable children with cystic fibrosis (CF) and healthy control children, and to examine the relationship between sleep quality and disease severity.

STUDY DESIGN

Clinically stable children with CF and healthy control children (7-18 years of age) were recruited. Sleep patterns and quality were measured at home with actigraphy (14 days). Overnight peripheral capillary oxygen saturation was measured via the use of pulse oximetry. Daytime sleepiness was evaluated by the Pediatric Daytime Sleepiness Scale (PDSS) and subjective sleep quality by the Sleep Disturbance Scale for Children and Obstructive Sleep Apnea-18.

RESULTS

A total of 87 children with CF and 55 control children were recruited with no differences in age or sex. Children with CF had significantly lower total sleep time and sleep efficiency than control children due to frequent awakenings and more wake after sleep onset. In children with CF, forced expiratory volume in 1 second and overnight peripheral capillary oxygen saturation nadir correlated positively with total sleep time and sleep efficiency and negatively with frequency of awakenings and wake after sleep onset. Patients with CF had significantly greater Sleep Disturbance Scale for Children (45 vs 35; P < .001), Obstructive Sleep Apnea-18 (35 vs 24; P < .001), and PDSS scores (14 vs 11; P < .001). There was a negative correlation between PDSS and forced expiratory volume in 1 second (r = -0.23; P < .05).

CONCLUSIONS

Even in periods of clinical stability, children with CF get less sleep than their peers due to more time in wakefulness during the night rather than less time spent in bed. Objective measures of sleep disturbance and subjective daytime sleepiness were related to disease severity. In contrast, parents of children with CF report high levels of sleep disturbance unrelated to disease severity.

Protective Effect of Aerobic Physical Activity on Sleep Behavior in Breast Cancer Survivors

HYPOTHESES

Sleep disorders are associated with an increased risk of cancer, including breast cancer (BC). Physical activity (PA) can produce beneficial effects on sleep.

STUDY DESIGN

We designed a randomized controlled trial to test the effect of 3 months of physical activity on sleep and circadian rhythm activity level evaluated by actigraphy.

METHODS

40 BC women, aged 35-70 years, were randomized into an intervention (IG) and a control group (CG). IG performed a 3 month of aerobic exercise. At baseline and after 3 months, the following parameters were evaluated both for IG and CG: anthropometric and body composition measurements, energy expenditure and motion level; sleep parameters (Actual Sleep Time-AST, Actual Wake Time-AWT, Sleep Efficiency-SE, Sleep Latency-SL, Mean Activity Score-MAS, Movement and Fragmentation Index-MFI and Immobility Time-IT) and activity level circadian rhythm using the Actigraph Actiwatch.

RESULTS

The CG showed a deterioration of sleep, whereas the IG showed a stable pattern. In the CG the SE, AST and IT decreased and the AWT, SL, MAS and MFI increased. In the IG, the SE, IT, AWT, SL, and MAS showed no changes and AST and MFI showed a less pronounced change in the IG than in the CG. The rhythmometric analysis revealed a significant circadian rhythm in two groups. After 3 months of PA, IG showed reduced fat mass %, while CG had improved weight and BMI.

CONCLUSION

Physical activity may be beneficial against sleep disruption. Indeed, PA prevented sleep worsening in IG. PA can represent an integrative intervention therapy able to modify sleep behaviour.