Sleep Characteristics According to Gender and Age Measured by Wrist Actigraphy

The sleep/wake rhythm is one of the most important biological rhythms. Quality and duration of sleep change during lifetime. The aim of our study was to determine differences in sleep efficiency, movement, and fragmentation during sleep period between genders and according to age. Sleep period was monitored by wrist actigraphy under home-based conditions. Seventy-four healthy participants—47 women and 27 men participated in the study. The participants were divided by age into groups younger than 40 years and 40 years and older. Women showed lower sleep fragmentation and mobility during sleep compared to men. Younger women showed a higher actual sleep and sleep efficiency compared to older women and younger men. Younger men compared to older men had a significantly lower actual sleep, lower sleep efficiency and significantly more sleep and wake bouts. Our results confirmed differences in sleep parameters between genders and according to age. The best sleep quality was detected in young women, but gender differences were not apparent in elderly participants, suggesting the impact of sex hormones on sleep.

Links Between Personality and Sleep Midpoint in Older Adults in the National Social Life, Health, and Aging Project

Chronotype has been linked to poor cognitive outcomes and mortality among older adults. Although previous studies indicate an association between personality and sleep, little is known about associations between personality and chronotype in older adults. We examined the association between personality and objective sleep midpoint (a measure of chronotype) in 463 older adults aged 73.5 ±7.7 from the National Social Life, Health, and Aging Project who completed the Midlife Developmental Inventory Personality scale and three nights of wrist actigraphy, from which we derived participants’ average sleep midpoints. After adjusting for demographics, higher conscientiousness was associated with earlier sleep midpoint (B=-0.53, SE=0.02, p<0.01). Associations for other traits were not significant. Findings link conscientiousness to chronotype and raise the possibility that earlier sleep timing may partially account for associations of conscientiousness with health outcomes. Further studies are needed investigating the role of personality in links of sleep and circadian factors with health.

Assessment of Sleep Duration Based on Ankle and Wrist Actigraphy in Hospitalized Older Patients

Poor sleep at time of hospitalization is associated with undesirable outcomes. Most studies performed in the hospital assess sleep by self-report, while only few rely on actigraphy. Although wrist actigraphy is commonly used for sleep assessment in field studies, in-hospital assessment may be challenging and cumbersome due to other more necessary monitoring devices that are often attached to patients’ upper limbs, that may in turn affect interpretation of wrist activity-data. Placement on the ankle may be a viable solution. In this pilot study, we aimed to compare total sleep time (TST) using concomitant wrist and ankle actigraphy as well as self-report. Twenty-one older adults (65+) hospitalized in medical units wore ankle and wrist actigraphy devices and subjectively estimated their TST for an average of (2.15±1.01) nights. A total of 45 nights were available for analysis. Average TST in minutes was 332.06±81.58, 427.05±97.74 and 374.28±124.96 based on wrist, ankle, and self-report, respectively. Repeated measure mixed models analysis was performed adjusting for age, gender, and sleep medications. TST was significantly lower using wrist compared to ankle actigraphy (F(2,102)=7.63, p=0.0008), and both were not different from self-report. No significant within subjects variation and no interaction between device and repeated measures were found. Despite differences between ankle and wrist assessments, all three provide consistent TST estimation within subjects. Self-report provides a stable and accessible assessment of TST, representing a good approximation of ankle and wrist actigraphy. Findings provide preliminary support for the use of ankle actigraphy for sleep assessment in hospital settings.

Finding a Composite Measure for Data From Wrist Actigraphy in Bipolar Disorder

Actigraphy can objectively measure sleep in studies on Bipolar Disorder (BD) where subjective sleep ratings might be influenced by affect. Actigraphy data are complex necessitating data reduction approaches. We created a composite score of actigraphy sleep metrics (total sleep time [TST], wake after sleep onset [WASO], and percent sleep [PS]) in BD. We computed z-scores of sleep measures for n=51 BD vs. n=80 healthy subjects and averaged scores. We examined associations with participant characteristics and used LASSO to identify metrics best explaining composite variability. Higher composite scores (better sleep) were seen in employed vs. unemployed (t=2.40, df=34, p=0.02), and correlated with higher medication load (r=0.41, p=0.004), lower mania symptomatology (r=-0.33, p=0.04) and lower interleukin (IL)-6 levels (r=-0.32, p=0.02). TST best explained variability in medication load and PS best explained employment, mania symptoms and IL-6. Given observed specificity of associations, selecting theory-driven sleep metrics may be more appropriate than a composite.

Efficacy of a Timed Activity Intervention to Improve Sleep: Findings From the Healthy Patterns Study

We conducted a two-arm RCT with dyads of 200 persons living at home with dementia (PLWD) who reported sleep disruption and family caregivers. Components of the Healthy Patterns intervention included: 1) assessing PLWD functional status, preferences and interests; 2) educating caregivers on environmental cues to promote activity and sleep; and 3) training caregivers in timed morning, afternoon, and evening activities. Outcomes included: PLWD quality of life, sleep, and neuropsychiatric symptoms. Sleep-wake patterns were assessed using wrist actigraphy and proxy-reported measures. The main intervention effects were tested using ANCOVA. The average age of participants was 73.4 years, 67% were female, 80% were African American/Black). At 4 weeks, the intervention group demonstrated less sleep-related impairment (p = 0.0031) and reported higher quality of life than the control group (p = 0.0074). These results provide new fundamental knowledge regarding the effects of timing activity on sleep and well-being.

Day and Night, Night and Day: Associations of Sleep and Activity Variability and Mortality

Self-reported sleep duration has been repeatedly found to predict mortality. Actigraphy has recently been added to population-based studies to provide more accurate sleep measures. Actigraphy sleep duration has not consistently predicted mortality, but actigraphy measures of sleep disruption measures are generally found to be predictive of mortality for older adults. A few studies have more fully used actigraphy data and constructed variables to summarize 24-hour activity patterns, which have also predicted mortality. In this study, we use a nationally representative study of Americans aged 61 – 91 to examine the associations between mortality and actigraphy-derived measures of variability, for both sleep and 24-hour activity patterns. We use 72-hour wrist actigraphy data from a substudy of the 2010/11 round of the National Social Life, Health and Aging Project (NSHAP) linked to the National Death Index (NDI) to establish 5-year mortality. Sleep variability was represented by sleep fragmentation and the standard deviation of wake and bed times. Intraday variability and between day (interday) variability described the 24-hour activity patterns. Cox proportional hazards models were adjusted for sociodemographic confounders and average daytime activity. In general, more variability was associated with increased death hazard for all measures. Fragmentation (HR: 1.04, 95% CI: [1.01, 1.07], p = 0.01), standard deviation of bedtimes (HR: 1.16, 95% CI: [1.02, 1.31], p = 0.02), and intraday variability (HR: 1.19, 95% CI: [0.98, 1.43], p = 0.07) showed the strongest associations. This study suggests that both consistent sleep and 24-hour activity patterns are associated with better prospective health.

Circadian Rest and Activity Rhythms and Cognitive Change in the Baltimore Longitudinal Study of Aging

Alterations in 24-hour movement patterns, or circadian rest/activity rhythms (RARs), commonly occur with aging. Using linear mixed effects (LME) modeling, we examined associations of baseline RARs with longitudinal change in cognition. Participants (N=424; 47% male, baseline age 72.8±10.1 years) were from the Baltimore Longitudinal Study of Aging and completed 5.6±0.8 nights of wrist actigraphy at baseline. Tests of memory, executive function, attention, language, and visuospatial ability were administered at baseline and subsequent visits (3.7±1.7 years of follow-up in those with >1 visit (n=295)). In unadjusted random intercept and slope LME models, greater RAR stability predicted slower memory decline, and higher activity during participants’ least active 5 hours (L5) predicted slower decline in visuospatial ability. After covariate adjustment, higher activity in participants’ most active 10 hours (M10) and higher L5 predicted slower decline in visuospatial ability (p<.05). Further research is needed on RARs as risk factors for later-life cognitive decline.

Approach to Common Sleep Disorders

Sleep disorders are highly relevant in clinical practice given their prevalence as well as their impact on health outcomes and quality of life. The most common concerns are excessive daytime sleepiness, insomnia, disordered breathing, and abnormal movements or behaviors during sleep. A detailed but targeted history is vital, particularly from the sleep partner/witness. In-laboratory sleep testing (polysomnography and multiple sleep latency test) remains vital in the diagnosis of certain sleep disorders (such as sleep-disordered breathing and central hypersomnia) and in specific populations (such as in children and individuals with comorbid medical disorders). Advances in technology have allowed for a variety of methods in assessing a patient's sleep, from compact devices to evaluate for sleep apnea, wrist actigraphy, and mobile device-based applications. As the pathophysiology of various sleep disorders becomes better elucidated, disease-specific medications have been developed for these conditions. Nonetheless, a multidisciplinary approach to management is necessary, including improving sleep hygiene and cognitive behavioral therapy.

A direct comparison of wrist actigraphy and sleep diaries in measuring sleep in healthy adults.

Measuring sleep and sleep quality is an important diagnostic and monitoring tool, and a number of different methods for measurement have been developed over the last half-century. Two prevalent methods include wrist actigraphy and sleep diaries. Both methods can be applied in different circumstances, but both have strengths and weaknesses. This study aimed to identify the extent to which there is congruence in the scores achieved by each method of sleep measurement. Sixty-eight respondents were asked to wear a wrist actigraphy and complete a sleep diary over the course of five days. There was a significant difference between the mean scores achieved using each measurement method, with actigraphy scores indicating lower total sleep time (TST) than diaries. However, this difference was not consistently present when the scores were compared on a day by day basis. Participant adherence is likely to fluctuate over the course of a sleep study and may undermine the accuracy of sleep diaries.

Variations in Sleep Characteristics and Glucose Regulation in Young Adults with Type 1 Diabetes

Context Short sleep duration and sleep disruptions are associated with impaired glucoregulation in type 1 diabetes (T1D). However, the mechanistic pathways between sleep and glucose variability remain unclear. Objective To determine within-and between-person associations between objective sleep-wake characteristics and glucose variability indices. Design/Setting Multilevel models (MLMs) were used to analyze concurrent sleep and glucose patterns over seven days in 42 young adults with T1D in their natural home environment. Patients or Other Participants Young adults with T1D (mean age of 22.2 ± 3.0 years, HbA1C 7.2%, 32.6% male) for at least 6 months with no other medical or major psychiatric comorbidity were included. Main Outcome Measure(s) Sleep-wake characteristics via wrist actigraphy and glucose variability indices via a continuous glucose monitor (CGM). Results Lower sleep efficiency predicted higher glucose variability (less time in range β= .011 and more time in hyperglycemia β= -.011) within-person. A longer wake after sleep onset and more sleep disruptions were associated with higher glucose variability between persons (β= .28 - .31). Higher glucose variability predicted poorer sleep within-person (delayed bedtime, waketime, mid-sleep time, and lower sleep efficiency), while higher glucose variability was associated with poorer sleep and more sleep disruptions between persons (lower sleep efficiency, longer wake after sleep onset, and a higher sleep fragmentation index). Conclusions Clinicians can address the reciprocal nature of the sleep-glucose relationship by optimizing sleep and targeting efforts towards a euglycemic range overnight. Sleep habits are a modifiable personal target in diabetes care.