We evaluated the performance of Fitbit Charge 3™ (FC3), a multi-sensor commercial sleep-tracker, for measuring sleep in adolescents against gold-standard laboratory polysomnography (PSG). Single-night PSG and FC3 sleep outcomes were compared in thirty-nine adolescents (22 girls; 16-19 years), 12 of whom presented with clinical/subclinical DSM-5 insomnia symptoms (7 girls). Discrepancy analysis, Bland-Altman plots, and epoch-by-epoch analyses were used to evaluate FC3 performance. The influence of several factors potentially affecting FC3 performance (e.g., sex, age, body mass index, firmware version, and magnitude of heart rate changes between consecutive PSG epochs) was also tested. In the sample of healthy adolescents, FC3 systematically underestimated PSG total sleep time by about 11 min and sleep efficiency by 2.5%, and overestimated wake after sleep onset by 9 min. Proportional biases were detected for “light” and “deep” sleep duration, resulting in significant underestimation of these parameters for those participants having longer PSG N1+ N2 and N3 durations, respectively. No significant systematic bias was detected for sleep efficiency and sleep onset latency. Epoch-by-epoch analysis showed sleep-stage sensitivity (average proportion of PSG epochs correctly classified by the device for a given sleep stage) of 68% for wake, 78% for “light” sleep, 59% for “deep” sleep, and 69% for rapid eye movement (REM) sleep in healthy sleepers. Similar results were found in the sample of adolescents with insomnia symptoms. Body mass index was positively associated with FC3-PSG discrepancies in wake after sleep onset (R 2 = .16, p = .048). The magnitude of the heart rate acceleration/deceleration between consecutive PSG epochs was an important factor affecting FC3 classifications of sleep stages. Our results are in line with a general trend in the literature, suggesting better performance for the recently introduced multi-sensor devices compared to motion-only devices, although further developments are needed to improve accuracy in sleep stage classification and wake detection. Further insight is needed to determine factors potentially affecting device performance, such as accuracy and reliability (consistency of performance over time), in different samples and conditions.
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Introduction: Insomnia disorder is a common sleep disorder and frequently emerges in the context of menopause, being associated with menopause-specific factors such as hot flashes and other psychosocial variables. Increased vulnerability to stress may also contribute to the development of insomnia in midlife women. Here, we aimed to investigate whether there are differences in physiological reactivity to acute psychosocial stress in women with menopausal insomnia compared with controls.
Methods: We investigated cortisol and heart rate [HR] responses to an acute experimental psychosocial stress (Trier Social Stress Test, TSST) approximately 1 h after waking in the morning in midlife women with ( n = 22) and without ( n = 16) DSM-IV insomnia disorder (Age: 50.05 ± 3.10 years), developed in the context of menopause.
Results: Despite similar perceived stress levels, women with insomnia showed blunted HR increases (~29% HR acceleration) to the TSST compared to controls (~44% HR acceleration) ( p = 0.026). No group differences in HR were detected at baseline or during post-task recovery. Cortisol stress responses were inconclusive, with most of the women (60%) failing to exhibit significant cortisol increases in response to the TSST. A greater magnitude of the cortisol awakening response (CAR) predicted the likelihood of being a non-responder ( p = 0.036), showing the confounding effect of CAR on cortisol stress responses.
Discussion: Women with menopausal insomnia show blunted cardiac responses to stress, suggesting alterations in the autonomic reactivity to acute stress. Whether these alterations are pre-existing or are a consequence of insomnia, needs to be determined.
Sleep and the autonomic nervous system (ANS) are intimately connected. The ANS is under the influence of circadian and sleep-dependent modulation. Forced desynchrony and constant routine protocols indicate strong circadian influences on heart rate (HR) and cardiac vagal activity, which fluctuate across 24 hours, with HR being lower, and vagal activity higher, during the nocturnal period. Sleep also influences ANS activity: during non-rapid-eye-movement (NREM) sleep, sympathetic activity is lower and vagal functioning is higher, compared to rapid-eye-movement (REM) sleep, where ANS activity is more similar to wakefulness. A change in ANS innervation of the heart and vasculature drives the wake-to-sleep reductions in blood pressure, HR, and systemic vascular resistance. The reduction in cardiovascular activity during sleep, prominent during NREM sleep, plays a key role in maintaining cardiovascular health, providing a “ cardiovascular holiday. ” Sleep-dependent as well as circadian regulation of vagal activity is evident very early in life and persists across adulthood. There is some evidence of sex differences in sleep-dependent vagal activity in adolescents as well as female hormone effects on nocturnal ANS measures, although further work is needed to determine the significance of these effects.
How the COVID‐19 Pandemic Has Changed Our Lives: A Study of Psychological Correlates Across 59 Countries
Objective: This study examined the impact of the COVID‐19 pandemic and subsequent social restrictions or quarantines on the mental health of the global adult population.
Method: A sample of 6,882 individuals ( M age = 42.30; 78.8% female) from 59 countries completed an online survey asking about several pandemic‐related changes in life and psychological status.
Results: Of these participants, 25.4% and 19.5% reported moderate‐to‐severe depression (DASS‐21) and anxiety symptoms (GAD‐7), respectively. Demographic characteristics (e.g. higher‐income country), COVID‐19 exposure (e.g., having had unconfirmed COVID‐19 symptoms), government‐imposed quarantine level, and COVID‐19‐based life changes (e.g., having a hard time transitioning to working from home; increase in verbal arguments or conflict with other adult in home) explained 17.9% of the variance in depression and 21.5% in anxiety symptoms.
Conclusions: In addition to posing a high risk to physical health, the COVID‐19 pandemic has robustly affected global mental health, so it is essential to ensure that mental health services reach individuals showing pandemic‐related depression and anxiety symptoms.
Effects of forehead cooling and supportive care on menopause-related sleep difficulties, hot flashes and menopausal symptoms: A pilot study.
Objective/Background: This pilot study explored the efficacy of a novel forehead cooling device for perceived sleep difficulties and hot flashes in menopausal-age women.
Participants: 20 women (55.1 ± 4.2 years; 19 post-menopausal) with insomnia symptoms and self-reported two or more hot flashes per day.
Methods: Participants completed daily assessments of sleep and hot flashes (via diaries) across 1 baseline week and 4 weeks of open-label, in-home, nightly treatment with a forehead cooling device (15–18°C) along with sleep hygiene instructions. They also completed ratings of insomnia and menopausal symptoms using standardized questionnaires.
Results: Women reported reductions in sleep onset latency (SOL), wakefulness after sleep onset (WASO), and nocturnal hot flash severity during the first week of treatment (SOL: 25.7 ± 18.4 min; WASO: 36.3 ± 27.3 min; hot flash severity: 3.0 ± 2.8) compared with baseline (SOL: 38 ± 26.3 min; WASO: 52.2 ± 35.6 min; hot flash severity: 6.8 ± 3.7), with further improvements after 2–4 weeks of use ( p < .001). There were also clinically meaningful reductions in insomnia severity and hot flash-related daily interference and lower psychological and physical symptom scores on the Greene climacteric scale after treatment (all p’s<0.001). Conclusions: This exploratory, naturalistic, pilot study shows that nightly use of a forehead cooling device produces improvements in self-reported sleep and reductions in insomnia, hot flash, and other menopausal, symptoms. Controlled studies are warranted to determine the role of this therapy in the management of sleep difficulties and menopausal symptoms in women. Further mechanistic studies are needed to understand the physiological impact of forehead cooling on sleep and menopausal symptoms.
SRI research scientists discuss new opportunities for large-scale data collection through consumer sleep technology
Consumer sleep technology (CST) is a fast-paced industry, and little is known about the accuracy and reliability of consumer sleep-tracking devices
A standardized framework for testing the performance of sleep-tracking technology: Step-by-step guidelines and open-source code
Sleep-tracking devices, particularly within the consumer sleep technology (CST) space, are increasingly used in both research and clinical settings, providing new opportunities for large-scale data collection in highly ecological conditions. Due to the fast pace of the CST industry combined with the lack of a standardized framework to evaluate the performance of sleep trackers, their accuracy and reliability in measuring sleep remains largely unknown. Here, we provide a step-by-step analytical framework for evaluating the performance of sleep trackers (including standard actigraphy), as compared to gold-standard polysomnography (PSG) or other reference methods. The analytical guidelines are based on recent recommendations for evaluating and using CST from our group and others (de Zambotti, Cellini, Goldstone, Colrain & Baker, 2019; Depner et al., 2019), and include raw data organization as well as critical analytical procedures, including discrepancy analysis, Bland-Altman plots, and epoch-by-epoch analysis. Analytical steps are accompanied by open-source R functions (depicted at https://sri-human-sleep.github.io/sleep-trackers-performance/AnalyticalPipeline_v1.0.0.html). In addition, an empirical sample dataset is used to describe and discuss the main outcomes of the proposed pipeline. The guidelines and the accompanying functions are aimed at standardizing the testing of CSTs performance, to not only increase the replicability of validation studies, but also to provide ready-to-use tools to researchers and clinicians. All in all, this work can help to increase the efficiency, interpretation, and quality of validation studies, and to improve the informed adoption of CST in research and clinical settings.
Stress, Sleep, and Autonomic Function in Healthy Adolescent Girls and Boys: Findings from the NCANDA Study
Objectives : Starting in adolescence, female sex is a strong risk factor for the development of insomnia. Reasons for this are unclear but could involve altered stress reactivity and/or autonomic nervous system (ANS) dysregulation, which are strongly associated with the pathophysiology of insomnia. We investigated sex differences in the effect of stress on sleep and ANS activity in adolescents, using the first night in the laboratory as an experimental sleep-related stressor.
Design : Repeated measures (first night vs. a subsequent night) with age (older/younger) and sex (males/females) as between factors.
Setting: Recordings were performed at the human sleep laboratory at SRI International.
Participants : One hundred six healthy adolescents (Age, mean ± SD: 15.2 ± 2.0 years; 57 boys).
Measures: Polysomnographic sleep, nocturnal heart rate (HR), and frequency-domain spectral ANS HR variability (HRV) indices.
Results : Boys and girls showed a first-night effect, characterized by lower sleep efficiency, lower %N1 and %N2 sleep, more wake after sleep onset and %N3 sleep, altered sleep microstructure (increased high-frequency sigma and Beta1 electroencephalographic activity), and reduced vagal activity ( P < .05) on the first laboratory night compared to a subsequent night. The first night ANS stress effect (increases in HR and suppression in vagal HRV during rapid eye movement sleep) was greater in girls than boys P < .05). Conclusions: Sleep and ANS activity were altered during the first laboratory night in adolescents, with girls exhibiting greater ANS alterations than boys. Findings suggest that girls may be more vulnerable than boys to sleep-specific stressors, which could contribute to their increased risk for developing stress-related sleep disturbances.
Impact of evening alcohol consumption on nocturnal autonomic and cardiovascular function in adult men and women: A dose–response laboratory investigation
Study Objectives: To investigate the dose-dependent impact of moderate alcohol intake on sleep-related cardiovascular (CV) function, in adult men and women.
Methods: A total of 26 healthy adults (30–60 years; 11 women) underwent 3 nights of laboratory polysomnographic (PSG) recordings in which different doses of alcohol (low: 1 standard drink for women and 2 drinks for men; high: 3 standard drinks for women and 4 drinks for men; placebo: no alcohol) were administered in counterbalanced order before bedtime. These led to bedtime average breath alcohol levels of up to 0.02% for the low doses and around 0.05% for the high doses. Autonomic and CV function were evaluated using electrocardiography, impedance cardiography, and beat-to-beat blood pressure monitoring.
Results: Presleep alcohol ingestion resulted in an overall increase in nocturnal heart rate (HR), suppressed total and high-frequency (vagal) HR variability, reduced baroreflex sensitivity, and increased sympathetic activity, with effects pronounced after high-dose alcohol ingestion (p’s < 0.05); these changes followed different dose- and measure-dependent nocturnal patterns in men and women. Systolic blood pressure showed greater increases during the morning hours of the high-alcohol dose night compared to the low-alcohol dose night and placebo, in women only (p’s < 0.05). Conclusions: Acute evening alcohol consumption, even at moderate doses, has marked dose- and time-dependent effects on sleep CV regulation in adult men and women. Further studies are needed to evaluate the potential CV risk of repeated alcohol-related alterations in nighttime CV restoration in healthy individuals and in those at high risk for CV diseases, considering sex and alcohol dose and time effects.
The use of immersive virtual reality and slow breathing to enhance relaxation and sleep in adolescents
Introduction: Sleep disturbances frequently emerge during adolescence amongst profound, normative, sleep maturation and biopsychosocial changes. Factors like stress, worry or rumination may make falling asleep and maintaining sleep more difficult. Here, we evaluate the efficacy of a novel intervention based on virtual reality (VR) and slow breathing to promote bedtime relaxation and facilitate sleep in high-school adolescents.
Methods: Twenty-nine 16-18 year-old adolescents with (N=9, 6 girls) and without (N=20, 11 girls) sleep difficulties underwent two counterbalanced in-lab relaxation and baseline polysomnography (PSG) nights. For the relaxation condition, immediately preceding bedtime, participants were engaged in slow diaphragmatic breathing (to promote physiological downregulation) whilst passively experiencing a relaxation immersive VR environment, designed to promote cognitive relaxation/distraction (20min). On the baseline night, participants engaged in quiet activities (e.g., reading a book) before bedtime (20min).
Results: The VR intervention resulted in a significant immediate increase in perceived relaxation and reduced worry (p<0.05). Also, heart rate dropped (~5bpm) in the pre-to-post intervention (p<0.05), while no significant change in heart rate was evident before and after the time spent in quiet activities on the baseline night. PSG-defined sleep onset latency was shorter (~6min reduction) and sleep efficiency was greater (~3% increase) on the VR relaxation night compared to the baseline night (p<0.05). In addition, baseline sleep onset latency was related to the magnitude of the baseline-to-relaxation reduction in sleep onset latency in participants (R2=0.70; p<0.01). There was no apparent difference in responses to the VR intervention between adolescents with or without insomnia. Conclusion: Our data highlight the potential for combining cognitive relaxation/distraction strategies, using immersive VR technology and physiological downregulation, to promote bedtime relaxation and improve overall sleep quality in adolescents. Further research is needed to evaluate the feasibility and effectiveness of such interventions over time. Support: National Heart, Lung and Blood Institute (NHLBI) R01HL139652 (to MdZ)
Reducing bedtime physiological arousal levels using immersive audio-visual respiratory bio-feedback: a pilot study in women with insomnia symptoms
Hyperarousal is a critical component of insomnia, particularly at bedtime when individuals are trying to fall asleep. The current study evaluated the effect of a novel, acute behavioral experimental manipulation (combined immersive audio-visual relaxation and biofeedback) in reducing bedtime physiological hyperarousal in women with insomnia symptoms. After a clinical/adaptation polysomnographic (PSG) night, sixteen women with insomnia symptoms had two random-order PSG nights: immersive audio-visual respiratory bio-feedback across the falling asleep period (manipulation night), and no pre-sleep arousal manipulation (control night). While using immersive audio-visual respiratory bio-feedback, overall heart rate variability was increased and heart rate (HR) was reduced (by ~ 5 bpm; p < 0.01), reflecting downregulation of autonomic pre-sleep arousal, relative to no-manipulation. HR continued to be lower during sleep, and participants had fewer awakenings and sleep stage transitions on the manipulation night relative to the control night (p < 0.05). The manipulation did not affect sleep onset latency or other PSG parameters. Overall, this novel behavioral approach targeting the falling asleep process emphasizes the importance of pre-sleep hyperarousal as a potential target for improving sleep and nocturnal autonomic function during sleep in insomnia.
Reproductive hormones are implicated in moderating pain. Animal studies support both pronociceptive and antinociceptive actions of oestradiol and progesterone suggesting that the net effect of these hormones on pain is complex and likely depends on the interaction between hormones and the extent of fluctuation rather than absolute hormone levels. Several clinical pain conditions show variation in symptom severity across the menstrual cycle. Though, there is still no consensus on whether the menstrual cycle influences experimental pain sensitivity in healthy individuals. Comprehensive literature searches on clinical and experimental pain across the menstrual cycle, as well as gonadal hormones and pain were performed using the electronic databases PubMed, Google Scholar and the Cochrane Library. Full-text manuscripts were reviewed for relevancy and reference lists were cross-checked for additional relevant studies. Most of the more recent, well-controlled studies show that menstrual cycle phase has no effect on the perception of pain in healthy, pain-free women. Although recent studies investigating pain-related brain activation have shown differential activation patterns across the menstrual cycle in regions involved with cognitive and motor function, even in the absence of a behavioural pain response, suggesting that cognitive pain and bodily awareness systems are sensitive to menstrual cycle phase. The interaction between the gonadal hormones and pain perception is intricate and not entirely understood. We suggest further investigations on the association between female reproductive hormones and pain sensitivity by exploring the interaction between clinical and experimental pain and the hormone changes that characterize puberty, post-partum and the menopause transition.
STUDY OBJECTIVES: To evaluate the accuracy in measuring nighttime sleep of a fitness tracker (Jawbone UP) compared to polysomnography (PSG).
Jawbone UP and PSG data were simultaneously collected from adolescents during an overnight laboratory recording. Agreements between Jawbone UP and PSG sleep outcomes were analyzed using paired t tests and Bland-Altman plots. Multiple regressions were used to investigate which PSG sleep measures predicted Jawbone UP “Sound sleep” and “Light sleep.”
SRI International Human Sleep Laboratory.
Sixty-five healthy adolescents (28 females, mean age ± standard deviation [SD]: 15.8 ± 2.5 y).
MEASUREMENTS AND RESULTS:
Outcomes showed good agreements between Jawbone UP and PSG for total sleep time (mean differences ± SD: -10.0 ± 20.5 min), sleep efficiency (mean differences ± SD: -1.9 ± 4.2 %), and wake after sleep onset (WASO) (mean differences ± SD: 10.6 ± 14.7 min). Overall, Jawbone UP overestimated PSG total sleep time and sleep efficiency and underestimated WASO but differences were small and, on average, did not exceed clinically meaningful cutoffs of > 30 min for total sleep time and > 5% for sleep efficiency. Multiple regression models showed that Jawbone UP “Sound sleep” measure was predicted by PSG time in N2 (β = 0.25), time in rapid eye movement (β = 0.29), and arousal index (β = -0.34). Jawbone UP “Light sleep” measure was predicted by PSG time in N2 (β = 0.48), time in N3 (β = 0.49), arousal index (β = 0.38) and awakening index (β = 0.28). Jawbone UP showed a progression from slight overestimation to underestimation of total sleep time and sleep efficiency with advancing age. All relationships were similar in boys and girls.
Jawbone UP shows good agreement with polysomnography in measures of total sleep time and wake after sleep onset in adolescent boys and girls. Further validation is needed in other age groups and clinical populations before advocating use of these inexpensive and easy-to-use devices in clinical sleep medicine and research.
Primary dysmenorrhea, or painful menstruation in the absence of pelvic pathology, is a common, and often debilitating, gynecological condition that affects between 45 and 95% of menstruating women. Despite the high prevalence, dysmenorrhea is often poorly treated, and even disregarded, by health professionals, pain researchers, and the women themselves, who may accept it as a normal part of the menstrual cycle. This review reports on current knowledge, particularly with regards to the impact and consequences of recurrent menstrual pain on pain sensitivity, mood, quality of life and sleep in women with primary dysmenorrhea.
Comprehensive literature searches on primary dysmenorrhea were performed using the electronic databases PubMed, Google Scholar and the Cochrane Library. Full-text manuscripts published between the years 1944 and 2015 were reviewed for relevancy and reference lists were cross-checked for additional relevant studies. In combination with the word ‘dysmenorrhea’ one or more of the following search terms were used to obtain articles published in peer-reviewed journals only: pain, risk factors, etiology, experimental pain, clinical pain, adenomyosis, chronic pain, women, menstrual cycle, hyperalgesia, pain threshold, pain tolerance, pain sensitivity, pain reactivity, pain perception, central sensitization, quality of life, sleep, treatment, non-steroidal anti-inflammatory drugs.
Women with dysmenorrhea, compared with women without dysmenorrhea, have greater sensitivity to experimental pain both within and outside areas of referred menstrual pain. Importantly, the enhanced pain sensitivity is evident even in phases of the menstrual cycle when women are not experiencing menstrual pain, illustrating that long-term differences in pain perception extend outside of the painful menstruation phase. This enhanced pain sensitivity may increase susceptibility to other chronic pain conditions in later life; dysmenorrhea is a risk factor for fibromyalgia. Further, dysmenorrheic pain has an immediate negative impact on quality of life, for up to a few days every month. Women with primary dysmenorrhea have a significantly reduced quality of life, poorer mood and poorer sleep quality during menstruation compared with their pain-free follicular phase, and compared with the menstruation phase of pain-free control women. The prescribed first-line therapy for menstrual pain remains non-steroidal anti-inflammatory drugs, which are effective in relieving daytime and night-time pain.
Further study is needed to determine whether effectively blocking dysmenorrheic pain ameliorates risk for the development of chronic pain disorders and to explore whether it is possible to prevent the development-and not just treat-severe dysmenorrheic pain in adolescent girls. In conclusion, we demonstrate the extensive multi-factorial impact of dysmenorrhea and we encourage and direct researchers to necessary future studies.
Cardiac Autonomic Function During Sleep: Effects of Alcohol Dependence and Evidence of Partial Recovery with Abstinence
Chronic alcoholism is associated with the development of cardiac and peripheral autonomic nervous system (ANS) pathology.