Meal-timing patterns and chronic disease prevalence in two representative Austrian studies.

PURPOSE: This study aimed at describing meal-timing patterns using cluster analysis and explore their association with sleep and chronic diseases, before and during COVID-19 mitigation measures in Austria. METHODS: Information was collected in two surveys in 2017 (N = 1004) and 2020 (N = 1010) in representative samples of the Austrian population. Timing of main meals, nighttime fasting interval, last-meal-to-bed time, breakfast skipping and eating midpoint were calculated using self-reported information. Cluster analysis was applied to identify meal-timing clusters. Multivariable-adjusted logistic regression models were used to study the association of meal-timing clusters with prevalence of chronic insomnia, depression, diabetes, hypertension, obesity and self-rated bad health status. RESULTS: In both surveys, median breakfast, lunch and dinner times on weekdays were 7:30, 12:30 and 18:30. One out of four participants skipped breakfast and the median number of eating occasions was 3 in both samples. We observed correlation between the different meal-timing variables. Cluster analysis resulted in the definition of two clusters in each sample (A17 and B17 in 2017, and A20 and B20 in 2020). Clusters A comprised most respondents, with fasting duration of 12-13 h and median eating midpoint between 13:00 and 13:30. Clusters B comprised participants reporting longer fasting intervals and later mealtimes, and a high proportion of breakfast skippers. Chronic insomnia, depression, obesity and self-rated bad health-status were more prevalent in clusters B. CONCLUSIONS: Austrians reported long fasting intervals and low eating frequency. Meal-timing habits were similar before and during the COVID-19-pandemic. Besides individual characteristics of meal-timing, behavioural patterns need to be evaluated in chrono-nutrition epidemiological studies.

The contribution of dispositional optimism to understanding insomnia symptomatology: Findings from a cross-sectional population study in Austria.

Attitudes and expectations of people towards their lives are essential to future health outcomes. Growing evidence has linked dispositional optimism to beneficial health outcomes, such as exceptional longevity, healthy aging and better sleep quality. We describe the association between dispositional optimism and chronic insomnia, considering potential mediators, in the Austrian Sleep Survey (N = 1,004), a population-based cross-sectional study conducted in 2017. Optimism was measured using the validated Life Orientation Test-Revised, and four different definitions were used to assess chronic insomnia. Three definitions were based on the criteria of chronic insomnia according to the International Classification of Sleep Disorders (3rd edn). Age- and multivariable-adjusted logistic regression models were used to calculate odds ratios (OR) and 95% confidence intervals (CIs). Among Austrians who were more optimistic, chronic insomnia risk was lower compared with those less optimistic (middle versus bottom tertile of optimism score: OR = 0.39, 95% CI, 0.22-0.70; and top versus bottom tertile: OR = 0.28, 95% CI, 0.14-0.54; p-trend < .001). Results were similar for all four definitions of insomnia, and differed slightly between men and women. Happiness, depression and health status confounded the association, whereas lifestyle did not. Promoting dispositional optimism could represent a simple and accessible strategy to improve sleep quality and lower insomnia risk, with downstream beneficial health effects. Further research is needed to clarify the prevention potential of interventions targeting this mental trait.

Working from home, quality of life, and perceived productivity during the first 50-day COVID-19 mitigation measures in Austria: a cross-sectional study.

OBJECTIVES: To explore changes in quality of life and perceived productivity, focusing on the effects of working from home during the first COVID-19 50-day mitigation period in Austria. METHODS: We conducted an Austrian-representative online survey (N = 1010) of self-reported life- and work-related changes during the first COVID-19 50-day mitigation period (March 16 through May 1 2020) compared to the situation before. We used multinominal logistic regression models to identify correlates of improved/decreased quality of life in the entire sample, and of improved/decreased productivity in a subsample of the working population (N = 686). We also calculated age- and multivariable-adjusted ORs and 95% CIs of an improved/decreased quality of life and an improved/decreased productivity by work from home status. RESULTS: During the COVID-19 mitigation period, quality of life improved in 17.5%, but decreased in 20.7% of the general Austrian population; perceived productivity at work increased in 12.7%, but decreased in 30.2% of the working population. Working from home during the mitigation period was associated with an increased quality of life (vs. none, partially: OR 2.07, 95% CI 1.09-3.91; all the time: 3.69, 1.86-7.29). In contrast, perceived productivity seemed to decrease when people worked from home (vs. none, partially: 1.42, 0.86-2.35; all the time: 1.48, 0.85-2.58). Working from home and related benefits were not equally distributed among gender, age, and educational attainment. CONCLUSIONS: A transition to more flexibility of workplace and working hours for employees could have important positive consequences for family and professional life, for stakeholders, for public health, and ultimately for the environment.

Contactless detection of periodic leg movements during sleep: A 3D video pilot study.

In clinical practice, the quality of polysomnographic recordings in children and patients with neurodegenerative diseases may be affected by sensor displacement and diminished total sleep time due to stress during the recording. In the present study, we investigated if contactless three-dimensional (3D) detection of periodic leg movements during sleep was comparable to polysomnography. We prospectively studied a sleep laboratory cohort from two Austrian sleep laboratories. Periodic leg movements during sleep were classified according to the standards of the World Association of Sleep Medicine and served as ground truth. Leg movements including respiratory-related events (A1) and excluding respiratory-related events (A2 and A3) were presented as A1, A2 and A3. Three-dimensional movement analysis was carried out using an algorithm developed by the Austrian Institute of Technology. Fifty-two patients (22 female, mean age 52.2 ± 15.1 years) were included. Periodic leg movement during sleep indexes were significantly higher with 3D detection compared to polysomnography (33.3 [8.1-97.2] vs. 30.7 [2.9-91.9]: +9.1%, p = .0055/27.8 [4.5-86.2] vs. 24.2 [0.00-88.7]: +8.2%, p = .0154/31.8 [8.1-89.5] vs. 29.6 [2.4-91.1]: +8.9%, p = .0129). Contactless automatic 3D analysis has the potential to detect restlessness mirrored by periodic leg movements during sleep reliably and may especially be suited for children and the elderly.

Procedural memory consolidation is associated with heart rate variability and sleep spindles.

Sleep and memory studies often focus on overnight rather than long-term memory changes, traditionally associating overnight memory change (OMC) with sleep architecture and sleep patterns such as spindles. In addition, (para-)sympathetic innervation has been associated with OMC after a daytime nap using heart rate variability (HRV). In this study we investigated overnight and long-term performance changes for procedural memory and evaluated associations with sleep architecture, spindle activity (SpA) and HRV measures (R-R interval [RRI], standard deviation of R-R intervals [SDNN], as well as spectral power for low [LF] and high frequencies [HF]). All participants (N = 20, Mage  = 23.40 ± 2.78 years) were trained on a mirror-tracing task and completed a control (normal vision) and learning (mirrored vision) condition. Performance was evaluated after training (R1), after a full-night sleep (R2) and 7 days thereafter (R3). Overnight changes (R2-R1) indicated significantly higher accuracy after sleep, whereas a significant long-term (R3-R2) improvement was only observed for tracing speed. Sleep architecture measures were not associated with OMC after correcting for multiple comparisons. However, individual SpA change from the control to the learning night indicated that only "SpA enhancers" exhibited overnight improvements for accuracy and long-term improvements for speed. HRV analyses revealed that lower SDNN and LF power was associated with better OMC for the procedural speed measure. Altogether, this study indicates that overnight improvement for procedural memory is specific for spindle enhancers, and is associated with HRV during sleep following procedural learning.

Managing daytime sleepiness with the help of sleepcoaching, a non-pharmacological treatment of non-restorative sleep.

PURPOSE: To measure the effect of a 2-day sleepcoaching seminar on daytime sleepiness and sleep-related variables of shift workers employed in an Austrian railway company (ÖBB: Österreichische Bundesbahnen). METHOD: Participants filled in pre- and post-intervention questionnaires, containing items of the PSQI and the ESS, questions about chronotype, personality factors and possible burnout risk factors. About 30 shift workers, working in shifts for more than 300 months on average (28 male; mean age = 24 ± 45.90, age range 24-56 years) voluntarily took part in the investigation twice. Sleep coaching by Holzinger and Kloesch™ (SC) is a new holistic approach for non-pharmacological treatment of non-restorative sleep and is based on Gestalt therapy. It includes psychotherapeutic aspects, which enable clients to improve their sleep quality by developing one's own coping strategies which can be implemented in daily routine. Dream work and relaxation techniques are also part of the programme. RESULTS: The 2-day SC seminar was beneficial by focusing on the sleep problems related to shift work. A significant improvement of the global PSQI score and the PSQI variables subjective sleep quality, diurnal fatigue, and sleep latency was achieved, with a medium effect size. However, the programme did not result in the reduction of daytime sleepiness (ESS). Six more variables did not change significantly. CONCLUSION: While some sleep problems related to shift work were successfully addressed by SC, daytime sleepiness (ESS) could not be reduced contrary to our expectations. More research with a greater sample and a longitudinal design is needed to examine the long-term effects of SC.

The effect of daytime napping and full-night sleep on the consolidation of declarative and procedural information.

Many studies investigating sleep and memory consolidation have evaluated full-night sleep rather than alternative sleep periods such as daytime naps. This multi-centre study followed up on, and was compared with, an earlier full-night study (Schabus et al., 2004) investigating the relevance of daytime naps for the consolidation of declarative and procedural memory. Seventy-six participants were randomly assigned to a nap or wake group, and performed a declarative word-pair association or procedural mirror-tracing task. Performance changes from before to after a 90-min retention interval filled with sleep or quiet wakefulness were evaluated between groups. Associations between performance changes, sleep architecture, spindles, and slow oscillations were investigated. For the declarative task we observed a trend towards stronger forgetting across a wake period compared with a nap period, and a trend towards memory increase over the full-night. For the procedural task, accuracy was significantly decreased following daytime wakefulness, showed a trend to increase with a daytime nap, and significantly increased across full-night sleep. For the nap protocol, neither sleep stages, spindles, nor slow oscillations predicted performance changes. A direct comparison of day and nighttime sleep revealed that daytime naps are characterized by significantly lower spindle density, but higher spindle activity and amplitude compared with full-night sleep. In summary, data indicate that daytime naps protect procedural memories from deterioration, whereas full-night sleep improves performance. Given behavioural and physiological differences between day and nighttime sleep, future studies should try to characterize potential differential effects of full-night and daytime sleep with regard to sleep-dependent memory consolidation.

The history of circadian rhythm research in Austria.

In view of the recent revival of interest in circadian biology and circadian epidemiology at the Medical University of Vienna, it seems appropriate to highlight the rich and pioneering history of circadian research in Austria. Among the forefathers of circadian research in Vienna are Otto Marburg (1874-1948), who discovered important elements of the pineal gland physiology, Robert Hofstätter (1883-1970), who used pineal gland extract in obstetrics/gynecology, and Paul Engel (1907-1997), who discovered that the pineal gland was controlled by light. More recently, Vera Lapin (1920-2007) showed that surgical removal of the pineal gland increased tumor growth, while Franz Waldhauser (*1946) investigated melatonin in conjunction with night work. Michael Kundi (*1950) and his team conducted among the first studies demonstrating differences in rhythms of night workers and early evidence for health impairments among them. Furthermore, Vienna-born Erhard Haus (1926-2013) pioneered the discovery of the role and importance of melatonin in relation to numerous diseases. This rich pioneering contribution of scientists in Vienna or with roots in Vienna is continued today by a new generation of chronobiologists, epidemiologists and clinicians in Vienna whose new insights contribute to the rapidly developing field of circadian rhythms research. Current topics and contributions relate to the impact of circadian rhythm disruption on health, and the application of chronotherapeutic approaches in clinical and preventive settings.

Guidelines for the recording and evaluation of pharmaco-sleep studies in man: the International Pharmaco-EEG Society (IPEG).

The International Pharmaco-EEG Society (IPEG) presents guidelines summarising the requirements for the recording and computerised evaluation of pharmaco-sleep data in man. Over the past years, technical and data-processing methods have advanced steadily, thus enhancing data quality and expanding the palette of sleep assessment tools that can be used to investigate the activity of drugs on the central nervous system (CNS), determine the time course of effects and pharmacodynamic properties of novel therapeutics, hence enabling the study of the pharmacokinetic/pharmacodynamic relationship, and evaluate the CNS penetration or toxicity of compounds. However, despite the presence of robust guidelines on the scoring of polysomnography -recordings, a review of the literature reveals inconsistent -aspects in the operating procedures from one study to another. While this fact does not invalidate results, the lack of standardisation constitutes a regrettable shortcoming, especially in the context of drug development programmes. The present guidelines are intended to assist investigators, who are using pharmaco-sleep measures in clinical research, in an effort to provide clear and concise recommendations and thereby to standardise methodology and facilitate comparability of data across laboratories.

Time Spent Outdoors and Associations with Sleep, Optimism, Happiness and Health before and during the COVID-19 Pandemic in Austria.

Social restriction measures (SRM) implemented during the COVID-19 pandemic led to a reduction in time spent outdoors (TSO). The aim of this study was to describe TSO and evaluate its association with sleep outcomes, optimism, happiness and health-status before and during SRM. Two online surveys were conducted in 2017 (N = 1004) and 2020, during SRM (N = 1010), in samples representative of the age, sex and region of the Austrian population. Information on the duration of TSO, sleep, optimism, happiness and health-status was collected. Multivariable-adjusted logistic regression models were used to study the association of TSO with chronic insomnia, short sleep, late chronotype, optimism, happiness and self-rated health-status. The mean TSO was 3.6 h (SD: 2.18) in 2017 and 2.6 h (SD: 1.87) during times of SRM. Men and participants who were older, married or in a partnership and lived in a rural area reported longer TSO. Participants who spent less time outdoors were more likely to report short sleep or a late chronotype in both surveys and, in 2020, also chronic insomnia. Less TSO was associated with lower happiness and optimism levels and poor health-status. Our findings suggest that TSO may be a protective factor for sleep, mood and health, particularly during stressful and uncertain times.

Morning headaches in snorers and their bed partners: a prospective diary study.

BACKGROUND: The prevalence and characteristics of morning headaches (MH) in habitual snorers are not well known, with only one retrospective study reporting MH in 23.5% of snorers. The role of MH in bed partners of snorers has not yet been examined. Therefore, the objective of this study was to assess MH prospectively in habitual snorers and their bed partners. METHODS: We recruited habitual snorers and their bed partners via newspaper articles. The participants completed a semistructured interview, filled in questionnaires about sleep quality, daytime sleepiness, depression and anxiety and kept a 90-day headache and sleep diary. RESULTS: We included a total of 102 snorers and 63 bed partners. Seventy-six snorers (25 female) and 41 bed partners (31 female) completed the study, recording a total of 6690 and 3497 diary days, respectively. MH was present on at least 1 day in 57% of the snorers and in 61% of the bed partners and recorded on 7.2% and 3.6% of the diary days, respectively. Independent predictors of MH in snorers were pre-study headache frequency (p < 0.001), anxiety disorder (p < 0.001), waking up because of pain (p = 0.002) and waking up too early (p < 0.001); and independent predictors in bed partners were migraine (p = 0.02), difficulties breathing during sleep (p < 0.001), waking up because of pain (p = 0.01) and waking up too early (p < 0.001). The analysis of couples only (n = 41) revealed pre-study headache frequency (p < 0.001), waking up too early (p < 0.001) and nocturnal confusion (p < 0.001) as independent predictors of MH in snorers, and migraine (p = 0.02), difficulties breathing during sleep (p < 0.001), waking up because of pain (p = 0.01) and waking up too early (p < 0.001) as independent predictors in bed partners. DISCUSSION: MH shows a 90-day prevalence of around 60% in habitual snorers as well as in their bed partners. Predictors of MH are related to sleep, headache and psychiatric comorbidity.

Revisiting the Concept of Vigilance.

Vigilance deficits can be observed after a period of prolonged, continuous wakefulness. In this context there has been extensive research targeting the impact of sleep deficits on different aspects of vigilance, but the underlying concept of vigilance was hardly ever addressed and discussed. One reason for this shortcoming is the unclear and ambiguous definition of the term vigilance, which is commonly used interchangeably with sustained attention and even wakefulness. This confusion is the result of a wide range of misleading definitions, starting in the 1940s, as psychologists redefined the concept of vigilance suggested by British Neurologist, Henry Head, in 1923. Nevertheless, the concept of vigilance is still useful and innovative, especially in treating sleep problems in children and young adults. This paper reviews the current usage of the term vigilance in sleep-wake-research and describes not only the benefits, but even more clearly, its limitations. By re-focusing on the definitions given by Henry Head, the concept of vigilance is an innovative way to gather new insights into the interplay between sleep- and daytime behaviors. In addition, future research on vigilance should consider three perspectives: 1st vigilance perceived as a process to allocate resources, 2nd vigilance associated with compensatory behaviors and 3rd the role of vigilance in human environmental interactions. This approach, understood as a conceptual framework, provides new perspectives by targeting sleep-wake behaviors as a 'real life' outcome measure, reflecting both physical and cognitive performance as well as sleep quality and quantity.

COVID-19 lockdown - Are Austrians finally able to compensate their sleep debt?

In order to control the rapid spread of the COVID-19 pandemic, Austria was put under national lockdown beginning on March 13, 2020, forcing its inhabitants to live in home confinement. The aim of this study was to measure the impact of the lockdown on sleep and dream behavior in Austrian citizens. 77 participants (50 women, M age = 40.88 years, S D age  = 13.72) filled in an online questionnaire during the lockdown between April and May 2020. Sleep quality, sleep quantity, daytime sleepiness, and nightmare frequency were assessed and analyzed in relation to gender, burnout risk, perfectionism and chronotype. Results demonstrated higher subjective sleep quality during lockdown, especially in women. Daytime sleepiness was significantly lower during the lockdown period while sleep duration did not change. Results suggest that sleep issues are less prominent during the COVID-19 lockdown but point to the importance of prevention and treatment of sleep disorders aside from the pandemic. Findings indicate the need for more flexibility in social time structures to relieve those managing tasks from multiple areas of interests such as working mothers. Generalization of results is limited due to small sample size, self-selection bias, and purely subjective measures.

Night today, day tomorrow: how irregular work shifts interfere with our psychological health.

The 24/7 economic activity has led to a growing demand for shift workers who now make up about 21% of the working population in Europe. Shift work causes desynchronization of biological and social rhythms and therefore increases the risk for physiological and psychological health issues. Night shifts, but in particular irregular shifts are considered to have numerous harmful effects on health and well-being. In this investigation, 185 shift workers employed at an Austrian railway company, filled in online questionnaires, which included the PSQI, the ESS, and items assessing sleep issues, their impact on life quality, and individual shift schedules. Results show that those shift workers who rated their shifts schedules as irregular reported significantly lower sleep quality according to the PSQI Global Score and the PSQI subscales subjective sleep quality, daytime sleepiness, and sleep duration. The probability of taking sleep medication was higher in shift workers whose schedules include more night shifts. In addition, participants who regularly worked on days after night shifts classified their complaints due to shift work as more severe. Future investigations should include more external and internal factors that influence the perception and handling of different working conditions. Nevertheless, our findings shed light on the particular situation of the railroad workers´population and show how important subjective perceptions are in dealing with shift work. The importance of sleep education and thematically relevant training becomes clear in order to prevent serious consequences on sleep and overall health.

Personality Traits and Insomnia Symptoms in Shift Workers.

The discrepancy between natural sleep-wake rhythm and actual sleep times in shift workers can cause sleep loss and negative daytime consequences. Irregular shift schedules do not follow a fixed structure and change frequently, which makes them particularly harmful and makes affected individuals more susceptible to insomnia. The present study compares insomnia symptoms of non-shift workers, regular shift workers, and irregular shift workers and takes into account the moderating role of the Big Five personality traits and levels of perfectionism. Employees of an Austrian railway company completed an online survey assessing shift schedules, sleep quality and duration, daytime sleepiness, and personality traits. A total of 305 participants, of whom 111 were non-shift workers, 60 regular shift workers, and 134 irregular shift workers, made up the final sample. Irregular shift workers achieved significantly worse scores than one or both of the other groups in time in bed, total sleep time, sleep efficiency, sleep duration, sleep quality, sleep latency, and the number of awakenings. However, the values of the irregular shifts workers are still in the average range and do not indicate clinical insomnia. Participants working regular shifts reported the best sleep quality and longest sleep duration and showed the least nocturnal awakenings, possibly due to higher conscientiousness- and lower neuroticism scores in this group. Agreeableness increased the effect of work schedule on total sleep time while decreasing its effect on the amount of sleep medication taken. Perfectionism increased the effect of work schedule on time in bed and total sleep time. Generalization of results is limited due to the high percentage of males in the sample and using self-report measures only.

Case Report: Why Sleep and Dream Related Psychological Treatments, Such as Sleepcoaching (According to Holzinger&Klösch) and CBT-I Should Be Implemented in Treatment Concepts in the Public Health System-Description of the Nightmare Treatment Process in the Context of PTSD.

In this case report, we explain the story of a woman diagnosed with severe PTSD, suffering from recurrent nightmares involving a traumatizing event. She participated in 6 week lucid dreaming training to help her reduce her nightmare frequency. Our descriptions include her dream reports as well as the results of the psychological assessment conducted. In only 6 weeks, she was able to begin to change her dream plots and to improve several of the psychological measures. In this case, we stated that paying more attention to sleep and, especially nightmares, not only in patients with PTSD, should be standard in treatment processes for psychiatric disorders. We, therefore, underpin our case with literature that explains the benefits of treatments, specifically for sleep problems that do not involve medication.

The (mis)perception of sleep: factors influencing the discrepancy between self-reported and objective sleep parameters.

STUDY OBJECTIVES: Self-reported perception of sleep often differs from objective sleep study measures, but factors predicting the discrepancy between self-reported and objective sleep parameters are controversial, and a comparison of laboratory vs ambulatory polysomnography (PSG) is lacking. METHODS: We retrospectively analyzed PSGs conducted between 2012 and 2016. Linear regression was applied to predict the discrepancy between self-reported and objective sleep parameters (total sleep time, sleep efficiency, sleep latency, using age, sex, arousal index, type of sleep disorder, and PSG type [laboratory vs ambulatory] as regressors). RESULTS: A total of 303 PSGs were analyzed (49% women, median age 48 years), comprising patients with insomnia (32%), sleep-related breathing disorders (27%), sleep-related movement disorders (15%), hypersomnia/narcolepsy (14%), and parasomnias (12%). Sleep disorder was the best predictor of discrepancy between self-reported and objective total sleep time, and patients with insomnia showed higher discrepancy values compared to all other patient groups (P < .001), independent of age and PSG type (P > .05). Contributory effects for higher discrepancy values were found for lower arousal index. Patients with insomnia underestimated both total sleep time (median discrepancy: 46 minutes, P < .001) and sleep efficiency (median discrepancy: 11%, P < .001). No significant predictor for discrepancy of sleep latency was found. CONCLUSIONS: Misperception of sleep duration and efficiency is common in sleep lab patients, but most prominent in insomnia, independent of age, sex, or laboratory vs ambulatory recording setting. This underlines the role of PSG in patients with a clinical diagnosis of insomnia and its use in cognitive behavioral therapy.

Sleep complaints in former and current night shift workers: findings from two cross-sectional studies in Austria.

Sleep impairment is highly prevalent in night shift workers, but evidence on the association of former night shift work (NSW) and its metrics (duration and frequency) in relation to sleep complaints is lacking. We evaluated the association of former and current NSW with chronic insomnia or circadian rhythm sleep disorder in a sample of the general worker (GW) population and in hospital workers (HW) in Austria. Information on sleep, NSW history, sociodemographic, and lifestyle factors was collected through an online cross-sectional survey in a representative sample of GW (N= 1,004) and a sample of HW (N= 799) between 2017 and 2019. Multi-variable adjusted logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for various measures of sleep (including chronic insomnia, daytime sleepiness, sleep duration, napping habits) and doctor-diagnosed chronic insomnia across NSW exposure (never night shift work; ever; ever/former; ever/current) and related metrics (cumulative duration, average frequency), compared to never NSW. Effect modification by chronotype and daytime napping was investigated. Former NSW was associated with higher odds of chronic insomnia in both samples (GW: OR = 2.28, 95% CI = 1.07-4.83; HW: OR = 1.17, 95% CI = 0.60-2.27). Chronic insomnia odds tended to increase among current night shift workers (HW: OR = 1.50, 95% CI = 0.79-2.83), compared to day workers. Higher NSW frequency (shifts/month) was associated with higher chronic insomnia odds in former night shift workers in both samples (GW: ORper shift/month = 1.06, 95% CI = 1.00-1.12; HW: ORper shift/month = 1.12, 95% CI = 1.00-1.25). Former NSW was also associated with increased daytime sleepiness among GW (OR = 2.26, 95% CI 1.28-3.99). Associations were more pronounced among early chronotypes and participants who reported no daytime naps. Our results suggest that NSW is associated with chronic insomnia even in the years after cessation of involvement in working it.

3D Camera and Pulse Oximeter for Respiratory Events Detection.

OBJECTIVE: The purpose of this study was to derive a respiratory movement signal from a 3D time-of-flight camera and to investigate if it can be used in combination with SpO2 to detect respiratory events comparable to polysomnography (PSG) based detection. METHODS: We derived a respiratory signal from a 3D camera and developed a new algorithm that detects reduced respiratory movement and SpO2 desaturation to score respiratory events. The method was tested on 61 patients' synchronized 3D video and PSG recordings. The predicted apnea-hypopnea index (AHI), calculated based on total sleep time, and predicted severity were compared to manual PSG annotations (manualPSG). Predicted AHI evaluation, measured by intraclass correlation (ICC), and severity classification were performed. Furthermore, the results were evaluated by 30-second epoch analysis, labelled either as respiratory event or normal breathing, wherein the accuracy, sensitivity, specificity and Cohen's kappa were calculated. RESULTS: The predicted AHI scored an ICC r = 0.94 (0.90 - 0.96 at 95% confidence interval, p < 0.001) compared to manualPSG. Severity classification scored 80% accuracy, with no misclassification by more than one severity level. Based on 30-second epoch analysis, the method scored a Cohen's kappa = 0.72, accuracy = 0.88, sensitivity = 0.80, and specificity = 0.91. CONCLUSION: Our detection method using SpO2 and 3D camera had excellent reliability and substantial agreement with PSG-based scoring. SIGNIFICANCE: This method showed the potential to reliably detect respiratory events without airflow and respiratory belt sensors, sensors that can be uncomfortable to patients and susceptible to movement artefacts.