Using Wearable Skin Temperature Data to Advance Tracking and Characterization of the Menstrual Cycle in a Real-World Setting.

The menstrual cycle is a loop involving the interplay of different organs and hormones, with the capacity to impact numerous physiological processes, including body temperature and heart rate, which in turn display menstrual rhythms. The advent of wearable devices that can continuously track physiological data opens the possibility of using these prolonged time series of skin temperature data to noninvasively detect the temperature variations that occur in ovulatory menstrual cycles. Here, we show that the menstrual skin temperature variation is better represented by a model of oscillation, the cosinor, than by a biphasic square wave model. We describe how applying a cosinor model to a menstrual cycle of distal skin temperature data can be used to assess whether the data oscillate or not, and in cases of oscillation, rhythm metrics for the cycle, including mesor, amplitude, and acrophase, can be obtained. We apply the method to wearable temperature data collected at a minute resolution each day from 120 female individuals over a menstrual cycle to illustrate how the method can be used to derive and present menstrual cycle characteristics, which can be used in other analyses examining indicators of female health. The cosinor method, frequently used in circadian rhythms studies, can be employed in research to facilitate the assessment of menstrual cycle effects on physiological parameters, and in clinical settings to use the characteristics of the menstrual cycles as health markers or to facilitate menstrual chronotherapy.

Performance evaluation of the open-source Yet Another Spindle Algorithm sleep staging algorithm against gold standard manual evaluation of polysomnographic records in adolescence.

GOAL AND AIMS: To evaluate an automatic sleep scoring algorithm against manual polysomnography sleep scoring. FOCUS METHOD/TECHNOLOGY: Yet Another Spindle Algorithm automatic sleep staging algorithm. REFERENCE METHOD/TECHNOLOGY: Manual sleep scoring. SAMPLE: 327 nights (151 healthy adolescents), from the NCANDA study. DESIGN: Participants underwent one-to-three overnight polysomnography recordings, one consisting of an event-related-potential paradigm. CORE ANALYTICS: Epoch by Epoch and discrepancy analyses (Bland Altman plots) were conducted on the overall sample. ADDITIONAL ANALYTICS AND EXPLORATORY ANALYSES: Epoch by Epoch and discrepancy analysis were repeated separately on standard polysomnography nights and event-related potential nights. Regression models were estimated on age, sex, scorer, and site of recording, separately on standard polysomnography nights and event-related potential nights. CORE OUTCOMES: The Yet Another Spindle Algorithm sleep scoring algorithm's average sensitivity of 93.04% for Wake, 87.67% for N2, 84.46% for N3, 86.02% for rapid-eye-movement, and 40.39% for N1. Specificity was 96.75% for Wake, 97.31% for N1, 88.87% for N2, 97.99% for N3, and 97.70% for rapid-eye-movement. The Matthews Correlation Coefficient was highest in rapid-eye-movement sleep (0.85) while lowest in N1 (0.39). Cohen's Kappa mirrored Matthews Correlation Coefficient results. In Bland-Altman plots, the bias between Yet Another Spindle Algorithm and human scoring showed proportionality to the manual scoring measurement size. IMPORTANT ADDITIONAL OUTCOMES: Yet Another Spindle Algorithm performance was reduced in event-related-potential/polysomnography nights for N3 and rapid-eye-movement. According to the Matthews Correlation Coefficient, the Yet Another Spindle Algorithm performance was affected by younger age, male sex, recording sites, and scorers. CORE CONCLUSION: Results support the use of Yet Another Spindle Algorithm to score adolescents' polysomnography sleep records, possibly with classification outcomes supervised by an expert scorer.

Effects of emerging alcohol use on developmental trajectories of functional sleep measures in adolescents.

STUDY OBJECTIVES: Adolescence is characterized by significant brain development, accompanied by changes in sleep timing and architecture. It also is a period of profound psychosocial changes, including the initiation of alcohol use; however, it is unknown how alcohol use affects sleep architecture in the context of adolescent development. We tracked developmental changes in polysomnographic (PSG) and electroencephalographic (EEG) sleep measures and their relationship with emergent alcohol use in adolescents considering confounding effects (e.g. cannabis use). METHODS: Adolescents (n = 94, 43% female, age: 12-21 years) in the National Consortium on Alcohol and Neurodevelopment in Adolescence (NCANDA) study had annual laboratory PSG recordings across 4-years. Participants were no/low drinkers at baseline. RESULTS: Linear mixed effect models showed developmental changes in sleep macrostructure and EEG, including a decrease in slow wave sleep and slow wave (delta) EEG activity with advancing age. Emergent moderate/heavy alcohol use across three follow-up years was associated with a decline in percentage rapid eye movement (REM) sleep over time, a longer sleep onset latency (SOL) and shorter total sleep time (TST) in older adolescents, and lower non-REM delta and theta power in males. CONCLUSIONS: These longitudinal data show substantial developmental changes in sleep architecture. Emergent alcohol use during this period was associated with altered sleep continuity, architecture, and EEG measures, with some effects dependent on age and sex. These effects, in part, could be attributed to the effects of alcohol on underlying brain maturation processes involved in sleep-wake regulation.

Stress, hypothalamic pituitary adrenal axis activity and autonomic nervous system function in adolescents with insomnia.

INTRODUCTION: Abnormal stress responses have been linked to the etiology of insomnia. We investigated the relationship between insomnia, stress, hypothalamic-pituitary-adrenal (HPA) axis activity, and autonomic nervous system (ANS) function in adolescence. METHODS: Forty-seven post-pubertal adolescents (16-20 years old, 28 female) with (N = 16; insomnia group) and without (N = 31; control group) DSM-5 insomnia symptoms were assessed for stress levels and stress reactivity and underwent a standardized stress protocol (Trier Social Stress Test (TSST)), after an overnight laboratory stay. Cortisol was measured upon awakening and 30-minutes later to calculate the cortisol awakening response (CAR). During the TSST, perceived stress, salivary cortisol (HPA activity), heart rate (HR) and blood pressure (BP) measures were collected. RESULTS: Participants in the insomnia group reported more stress from school performance and work overload, with insomnia girls experiencing more stress from peer pressure and future uncertainty than control girls (p < 0.05). No group differences were detected in the CAR and pre-TSST stress levels. All participants showed significant increases in perceived stress (~19 %), HR (~33 %), systolic (~13 %), and diastolic (~15 %) BP in response to the TSST (p < 0.05). Overall HR stress response did not differ between groups, but was lower in boys with insomnia than in girls with insomnia (p < 0.05). Cortisol stress responses were inconclusive, possibly due to a masking effect of CAR, as the task was performed shortly after awakening and larger CARs were associated with blunted cortisol stress responses. DISCUSSION: Results mostly show no group difference in physiological stress responses, although some interaction effects suggest a potential sex by insomnia interaction. Larger samples are needed to understand the physiological disturbances of insomnia in adolescence.

Wearable and mobile technology to characterize daily patterns of sleep, stress, presleep worry, and mood in adolescent insomnia.

OBJECTIVES: Characterizing daily patterns of sleep, stress, presleep worry, and mood in adolescents with and without insomnia symptomatology. DESIGN: Two months of continuous wearable tracking and daily diary ratings. SETTING: Free-living conditions. PARTICIPANTS: Ninety-three adolescents (59 girls; 16-19 years old) with (N = 47; 26 with clinical and 21 with sub-clinical) and without (N = 46; control) DSM-5 insomnia symptomatology. MEASUREMENTS: Fitbit Charge 3 tracked sleep, heart rate, and steps. Evening electronic diaries collected ratings of daily stress, presleep worry, and mood. RESULTS: While sleep duration (control: 6.88 ± 1.41 hours; insomnia: 6.92 ± 1.28 hours), architecture, timing, and night-to-night variability were similar between groups, the insomnia group reported higher levels of stress and worry, being mainly related to "school". At the intraindividual level, stress and worry predicted shorter sleep duration and earlier wake up times, which, in turn, predicted higher stress the following day. Moreover, higher-than-usual stress predicted higher sleep-time heart rate, with a more consistent effect in adolescents with insomnia. Results were overall consistent after controlling for covariates and several robustness checks. CONCLUSIONS: There is a bidirectional relationship between daily stress and sleep, with daily stress negatively impacting sleep, which in turn leads to more stress in adolescents with and without insomnia symptoms. Findings also highlight the complexity of insomnia in adolescence, in which the core clinical features (perceived sleep difficulties) and the critical factors (stress/worry) implicated in the pathophysiology of the disorder are not necessarily reflected in objective sleep indicators.

Risk for depression tripled during the COVID-19 pandemic in emerging adults followed for the last 8 years.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has significantly increased depression rates, particularly in emerging adults. The aim of this study was to examine longitudinal changes in depression risk before and during COVID-19 in a cohort of emerging adults in the U.S. and to determine whether prior drinking or sleep habits could predict the severity of depressive symptoms during the pandemic. METHODS: Participants were 525 emerging adults from the National Consortium on Alcohol and NeuroDevelopment in Adolescence (NCANDA), a five-site community sample including moderate-to-heavy drinkers. Poisson mixed-effect models evaluated changes in the Center for Epidemiological Studies Depression Scale (CES-D-10) from before to during COVID-19, also testing for sex and age interactions. Additional analyses examined whether alcohol use frequency or sleep duration measured in the last pre-COVID assessment predicted pandemic-related increase in depressive symptoms. RESULTS: The prevalence of risk for clinical depression tripled due to a substantial and sustained increase in depressive symptoms during COVID-19 relative to pre-COVID years. Effects were strongest for younger women. Frequent alcohol use and short sleep duration during the closest pre-COVID visit predicted a greater increase in COVID-19 depressive symptoms. CONCLUSIONS: The sharp increase in depression risk among emerging adults heralds a public health crisis with alarming implications for their social and emotional functioning as this generation matures. In addition to the heightened risk for younger women, the role of alcohol use and sleep behavior should be tracked through preventive care aiming to mitigate this looming mental health crisis.

An international study of post-COVID sleep health.

OBJECTIVES: COVID-19 has infected millions of people worldwide, with growing evidence that individuals with a history of infection may continue to show persistent post-COVID symptoms (long COVID). The aim of this study was to investigate sleep health in an international sample of individuals who reported previously testing positive for COVID-19. DESIGN: Cross-sectional. SETTING: Online survey distributed online between March and June 2021. PARTICIPANTS: A total of 1001 individuals who reported a positive diagnosis of COVID-19 across different geographical regions, including North and South America, Sub-Saharan Africa, and Europe. MEASUREMENTS: Self-reported sleep health, using the Regulatory Satisfaction Alertness Timing Efficiency Duration scale, as recalled before a COVID-19 diagnosis and also reported currently. RESULTS: Individuals reported worse overall current sleep health, with lower ratings across the 6 dimensions of sleep health (sleep regularity, satisfaction, alertness, timing, efficiency, and duration) compared to their ratings as recalled before COVID-19 infection. Greater severity of COVID-19 symptoms was the strongest predictor of poor current sleep health (P < .001), independent of demographics, presence of a pre-existing chronic health condition, and time since infection. Poor current sleep health was associated with poorer current quality of life (P < .001). CONCLUSIONS: Poor current sleep health is evident in individuals with a history of COVID-19, particularly those with more severe symptoms at the time of their COVID-19 infection and is associated with a poorer quality of life. Clinicians and researchers should assess sleep health in COVID-19 patients and investigate long-term associations with their mental and physical health, as well as potential benefits of improving sleep in this population.

Earlier Bedtime and Effective Coping Skills Predict a Return to Low-Risk of Depression in Young Adults during the COVID-19 Pandemic.

To determine the persistent effects of the pandemic on mental health in young adults, we categorized depressive symptom trajectories and sought factors that promoted a reduction in depressive symptoms in high-risk individuals. Specifically, longitudinal analysis investigated changes in the risk for depression before and during the pandemic until December 2021 in 399 young adults (57% female; age range: 22.8 ± 2.6 years) in the United States (U.S.) participating in the National Consortium on Alcohol and NeuroDevelopment in Adolescence (NCANDA) study. The Center for Epidemiologic Studies Depression Scale (CES-D-10) was administered multiple times before and during the pandemic. A score ≥10 identified individuals at high-risk for depression. Self-reported sleep behavior, substance use, and coping skills at the start of the pandemic were assessed as predictors for returning to low-risk levels while controlling for demographic factors. The analysis identified four trajectory groups regarding depression risk, with 38% being at low-risk pre-pandemic through 2021, 14% showing persistent high-risk pre-pandemic through 2021, and the remainder converting to high-risk either in June 2020 (30%) or later (18%). Of those who became high-risk in June 2020, 51% were no longer at high-risk in 2021. Logistic regression revealed that earlier bedtime and, for the older participants (mid to late twenties), better coping skills were associated with this declining risk. Results indicate divergence in trajectories of depressive symptoms, with a considerable number of young adults developing persistent depressive symptoms. Healthy sleep behavior and specific coping skills have the potential to promote remittance from depressive symptoms in the context of the pandemic.

A dataset reflecting the multidimensionality of insomnia symptomatology in adolescence using standardized questionnaires.

Insomnia is the most common sleep disorder in adolescence, and frequently emerges during this vulnerable period of profound biobehavioral maturation. Insomnia tends to be chronic, and if left untreated, could be detrimental for the teenagers' mental and physical health, social, and emotional development. However, there is a paucity of data about insomnia in adolescence, strongly limiting the understanding and management of the disorder. In the current work, psychological and behavioral questionnaire data are provided for 95 adolescents (age range between 16-19 years, 62% female) with and without clinical or subclinical insomnia symptoms, determined from the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Data were collected as part of a larger study investigating insomnia pathophysiology and cardiovascular health in adolescence. The data collection strategy was designed to capture the complexity of the insomnia symptomology in adolescence, and its unique clinical features, across different psychological and behavioral domains. The dataset covers a broad range of clinical measures describing sleep quality and habits, sleep-related cognitions, stress, stress reactivity, coping and emotion regulation behavior, mood, personality, and childhood trauma. The relationships between symptoms are analyzed and visualized via a network analysis approach, including outputs reflecting network structures and centrality measures. This dataset, and associated data visualizations, could be beneficial in the fields of sleep medicine, adolescent health, and development of psychopathology, highlighting the specific factors implicated in adolescent insomnia, as well as the heterogeneity of symptom combinations. Results can potentially inform the development of therapeutic approaches targeting key factors implicated in the insomnia pathophysiology in adolescents.

A virtual reality-based mind-body approach to downregulate psychophysiological arousal in adolescent insomnia.

Objective: In this study, we describe the rationale, supported by preliminary data, for a novel, digital, immersive virtual reality (VR)-based mind-body approach, designed to reduce bedtime arousal in adolescents with insomnia. Methods: Fifty-two high-school students (16-20 years; 32 female) with (N = 18) and without (N = 34) DSM-5 insomnia symptoms engaged with 20 min of immersive VR-guided meditation and paced breathing (0.1 Hz) (intervention condition) and 20 min of quiet activity (control condition), right before bedtime, on two separate evenings. Results: The intervention resulted in acute autonomic and cortical modulation (p < 0.05), leading to reduced physiological arousal (↓heart rate, ↓cortisol) compared with the control condition, with similar effects in adolescents with and without insomnia. No significant changes were detected for cognitive arousal levels. During the intervention, all participants were able to achieve the targeted 0.1 Hz breathing rate, and the majority experienced no discomfort associated with the VR exposure. However, 30-40% of the participants experienced some trouble slowing down their breathing. Conclusions: The study provides supporting preliminary evidence for the mechanism behind a novel VR-based digital approach, designed to regulate psychophysiological arousal levels by acting on neurocognitive and autonomic pathways. Further studies (e.g. randomized clinical trials) are needed to evaluate the isolated and synergistic effects of its components (e.g. VR vs. VR + paced breathing), and its efficacy, acceptance, and feasibility in alleviating insomnia symptoms in adolescents.

Did the acute impact of the COVID-19 pandemic on drinking or nicotine use persist? Evidence from a cohort of emerging adults followed for up to nine years.

OBJECTIVE: This study examined the impact of the COVID-19 pandemic on drinking and nicotine use through June of 2021 in a community-based sample of young adults. METHOD: Data were from 348 individuals (49% female) enrolled in a long-term longitudinal study with an accelerated longitudinal design: the National Consortium on Alcohol and Neurodevelopment in Adolescence (NCANDA) Study. Individuals completed pre-pandemic assessments biannually from 2016 to early 2020, then completed up to three web-based, during-pandemic surveys in June 2020, December 2020, and June 2021. Assessments when individuals were 18.8-22.4 years old (N = 1,458) were used to compare drinking and nicotine use pre-pandemic vs. at each of the three during-pandemic timepoints, adjusting for the age-related increases expected over time. RESULTS: Compared to pre-pandemic, participants were less likely to report past-month drinking in June or December 2020, but there was an increase in drinking days among drinkers in June 2020. By June 2021, both the prevalence of past-month drinking and number of drinking days among drinks were similar to pre-pandemic levels. On average, there were no statistically significant differences between pre-pandemic and during-pandemic time points for binge drinking, typical drinking quantity, or nicotine use. Young adults who reported an adverse financial impact of the pandemic showed increased nicotine use while their peers showed stable or decreased nicotine use. CONCLUSION: Initial effects of the pandemic on alcohol use faded by June 2021, and on average there was little effect of the pandemic on nicotine use.

Clinical characterization of insomnia in adolescents - an integrated approach to psychopathology.

OBJECTIVES/BACKGROUND: Insomnia in adolescence is common and debilitating yet it remains poorly understood. Here, we examine the complexity of clinical, behavioral, and psychosocial factors characterizing insomnia in adolescents. METHODS: Ninety-five adolescents (16-19 years) with (N = 47, 31 female) and without (N = 48, 28 female) insomnia symptoms participated. In the insomnia group, 26 (20 female) met full DSM-5 criteria for insomnia disorder, while 21 (11 female) met partial criteria. Participants completed a clinical interview and assessments of clinical, behavioral, and psychosocial dimensions associated with insomnia. GLMs and network analyses were used to evaluate group and sex differences in severity and inter-relationships between symptoms. RESULTS: Adolescents with insomnia symptomatology had lower sleep hygiene and thought control, more depressive symptoms and dysfunctional sleep-related cognitions, and more substance use as a coping behavior than healthy controls. They also indicated higher neuroticism, stress levels, and sleep stress reactivity (p < 0.05), but no difference in adverse childhood experiences, than controls. Girls compared to boys with insomnia reported lower sleep quality, and more pre-sleep cognitive activity and sleep stress reactivity (p < 0.05). Compared to healthy girls, girls in the insomnia group reported lower sleep hygiene and higher agreeableness. Network analyses confirmed profound group differences in network topology, with the insomnia group having different levels of centrality and relationships between clinical characteristics compared with controls. CONCLUSIONS: Findings highlight clinical and sex-specific characteristics of adolescent insomnia, with network analyses revealing a complex interplay between clinical, behavioral, and psychosocial domains. Adolescents with insomnia symptoms, particularly girls, may benefit from interventions to improve negative cognition, mood, and stress, and behavioral strategies to counteract sleep-related maladaptive behaviors.

The Pandemic's Toll on Young Adolescents: Prevention and Intervention Targets to Preserve Their Mental Health.

PURPOSE: Adolescence is characterized by dramatic physical, social, and emotional changes, making teens particularly vulnerable to the mental health effects of the COVID-19 pandemic. This longitudinal study identifies young adolescents who are most vulnerable to the psychological toll of the pandemic and provides insights to inform strategies to help adolescents cope better in times of crisis. METHODS: A data-driven approach was applied to a longitudinal, demographically diverse cohort of more than 3,000 young adolescents (11-14 years) participating in the ongoing Adolescent Brain Cognitive Development Study in the United States, including multiple prepandemic visits and three assessments during the COVID-19 pandemic (May-August 2020). We fitted machine learning models and provided a comprehensive list of predictors of psychological distress in individuals. RESULTS: Positive affect, stress, anxiety, and depressive symptoms were accurately detected with our classifiers. Female sex and prepandemic internalizing symptoms and sleep problems were strong predictors of psychological distress. Parent- and youth-reported pandemic-related psychosocial factors, including poorer quality and functioning of family relationships, more screen time, and witnessing discrimination in relation to the pandemic further predicted youth distress. However, better social support, regular physical activities, coping strategies, and healthy behaviors predicted better emotional well-being. DISCUSSION: Findings highlight the importance of social connectedness and healthy behaviors, such as sleep and physical activity, as buffering factors against the deleterious effects of the pandemic on adolescents' mental health. They also point to the need for greater attention toward coping strategies that help the most vulnerable adolescents, particularly girls and those with prepandemic psychological problems.

Trauma-Related Distress During the COVID-19 Pandemic In 59 Countries.

The COVID-19 pandemic has upended life like few other events in modern history, with differential impacts on varying population groups. This study examined trauma-related distress among 6,882 adults ages 18 to 94 years old in 59 countries during April to May 2020. More than two-thirds of participants reported clinically significant trauma-related distress. Increased distress was associated with unemployment; identifying as transgender, nonbinary, or a cisgender woman; being from a higher income country; current symptoms and positive diagnosis of COVID-19; death of a loved one; restrictive government-imposed isolation; financial difficulties; and food insecurity. Other factors associated with distress included working with potentially infected individuals, care needs at home, a difficult transition to working from home, conflict in the home, separation from loved ones, and event restrictions. Latin American and Caribbean participants reported more trauma-related distress than participants from Europe and Central Asia. Findings inform treatment efforts and highlight the need to address trauma-related distress to avoid long-term mental health consequences.

Altered resting-state functional connectome in major depressive disorder: a mega-analysis from the PsyMRI consortium.

Major depressive disorder (MDD) is associated with abnormal neural circuitry. It can be measured by assessing functional connectivity (FC) at resting-state functional MRI, that may help identifying neural markers of MDD and provide further efficient diagnosis and monitor treatment outcomes. The main aim of the present study is to investigate, in an unbiased way, functional alterations in patients with MDD using a large multi-center dataset from the PsyMRI consortium including 1546 participants from 19 centers ( www.psymri.com ). After applying strict exclusion criteria, the final sample consisted of 606 MDD patients (age: 35.8 ± 11.9 y.o.; females: 60.7%) and 476 healthy participants (age: 33.3 ± 11.0 y.o.; females: 56.7%). We found significant relative hypoconnectivity within somatosensory motor (SMN), salience (SN) networks and between SMN, SN, dorsal attention (DAN), and visual (VN) networks in MDD patients. No significant differences were detected within the default mode (DMN) and frontoparietal networks (FPN). In addition, alterations in network organization were observed in terms of significantly lower network segregation of SMN in MDD patients. Although medicated patients showed significantly lower FC within DMN, FPN, and SN than unmedicated patients, there were no differences between medicated and unmedicated groups in terms of network organization in SMN. We conclude that the network organization of cortical networks, involved in processing of sensory information, might be a more stable neuroimaging marker for MDD than previously assumed alterations in higher-order neural networks like DMN and FPN.

DLPFC volume is a neural correlate of resilience in healthy high-risk individuals with both childhood maltreatment and familial risk for depression.

BACKGROUND: Two prominent risk factors for major depressive disorder (MDD) are childhood maltreatment (CM) and familial risk for MDD. Despite having these risk factors, there are individuals who maintain mental health, i.e. are resilient, whereas others develop MDD. It is unclear which brain morphological alterations are associated with this kind of resilience. Interaction analyses of risk and diagnosis status are needed that can account for complex adaptation processes, to identify neural correlates of resilience. METHODS: We analyzed brain structural data (3T magnetic resonance imaging) by means of voxel-based morphometry (CAT12 toolbox), using a 2 × 2 design, comparing four groups (N = 804) that differed in diagnosis (healthy v. MDD) and risk profiles (low-risk, i.e. absence of CM and familial risk v. high-risk, i.e. presence of both CM and familial risk). Using regions of interest (ROIs) from the literature, we conducted an interaction analysis of risk and diagnosis status. RESULTS: Volume in the left middle frontal gyrus (MFG), part of the dorsolateral prefrontal cortex (DLPFC), was significantly higher in healthy high-risk individuals. There were no significant results for the bilateral superior frontal gyri, frontal poles, pars orbitalis of the inferior frontal gyri, and the right MFG. CONCLUSIONS: The healthy high-risk group had significantly higher volumes in the left DLPFC compared to all other groups. The DLPFC is implicated in cognitive and emotional processes, and higher volume in this area might aid high-risk individuals in adaptive coping in order to maintain mental health. This increased volume might therefore constitute a neural correlate of resilience to MDD in high risk.

Performance of Fitbit Charge 3 against polysomnography in measuring sleep in adolescent boys and girls.

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 (R2 = .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.

Physiological responses to acute psychosocial stress in women with menopausal insomnia.

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.

Sleeping when the world locks down: Correlates of sleep health during the COVID-19 pandemic across 59 countries.

OBJECTIVES: COVID-19 escalated into a global pandemic affecting countries around the world. As communities shut down to reduce disease spread, all aspects of life have been altered, including sleep. This study investigated changes in sleep patterns and correlates of sleep health in a global sample and examined relationships between sleep health and psychological distress. DESIGN: Cross-sectional. SETTINGS: Online survey distributed between April 19 and May 3, 2020. PARTICIPANTS: Total 6882 participants (18-94 years) across 59 countries. MEASUREMENTS: Sleep health (RU-SATED), demographics, pandemic-related factors, mood. RESULTS: More than half the sample shifted their sleep toward later bed- and wake-times, and more than a third reported increased sleep disturbances during the pandemic. Older age, being partnered, and living in a higher income country were associated with better sleep health, while a stricter level of quarantine and pandemic-related factors (being laid off from job, financial strain, or difficulties transitioning to working from home) were associated with poorer sleep health. Domestic conflict was the strongest correlate of poorer sleep health. Poorer sleep health was strongly associated with greater depression and anxiety symptoms. Participants from Latin America reported the lowest sleep health scores. CONCLUSIONS: COVID-19-associated factors have impacted sleep health on a global level. While our data are correlational, sleep health is strongly linked with mental health and could play a protective role against developing mental distress during pandemic-related isolation. Sleep health should be incorporated into public health messages aimed at helping people cope with the effects of a pandemic to maintain optimal mental and physical health.