The 1968 Rechtschaffen and Kales (R & K) sleep scoring manual was published 15 years after REM sleep was discovered. Advances in the ensuing 28 years warranted a re-look at visual scoring of sleep stages. This paper describes the work of the AASM Visual Scoring Task Force, including methodology, a literature review and the rationale behind the new rules. Reliability studies of R & K scoring were reviewed; reliability was low for stage one and moderate for slow wave sleep. Evidence indicated that K complexes and slow waves are expressed maximal frontally, spindles centrally and alpha rhythm over the occipital region. Three derivations of EEG, two of electro-oculography, and one of chin EMG were recommended. Scoring by 30-second epochs was retained. New terminology for sleep stages was proposed. Attenuation of alpha rhythm was determined to be the most valid electrophysiological marker of sleep onset. Alternative measures were proposed for non-alpha generating subjects. K complexes associated with arousals were determined to be insufficient alone to define the new stage N2. No evidence was found to justify dividing slow wave sleep into two stages. No reasons were found to alter the current slow wave amplitude criteria at any age. The phenomena of REM sleep were defined. The rules for defining onset and termination of REM sleep periods were simplified. Movement time was eliminated and major body movements defined. Studies are needed to test the reliability of the new rules. Future advances in technology may require modification of these rules with time.

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Importance and study objective The COVID-19 pandemic has produced unprecedented changes in social, work, and leisure activities, which all have had major impact on sleep and psychological well-being. This study documented the prevalence of clinical cases of insomnia, anxiety, and depression and selected risk factors (COVID-19, confinement, financial burden, social isolation) during the first wave of the pandemic in 13 countries throughout the world. Design and participants International, multi-center, harmonized survey of 22 330 adults (mean age = 41.9 years old, range 18–95; 65.6% women) from the general population in 13 countries and four continents. Participants were invited to complete a standardized web-based survey about sleep and psychological symptoms during the first wave of the COVID-19 pandemic from May to August 2020. Results Clinical insomnia symptoms were reported by 36.7% (95% CI, 36.0–37.4) of respondents and 17.4% (95% CI, 16.9–17.9) met criteria for a probable insomnia disorder. There were 25.6% (95% CI, 25.0–26.2) with probable anxiety and 23.1% (95% CI, 22.5–23.6) with probable depression. Rates of insomnia symptoms (>40%) and insomnia disorder (>25%) were significantly higher in women, younger age groups, and in residents of Brazil, Canada, Norway, Poland, USA, and United Kingdom compared to residents from Asian countries (China and Japan, 8% for disorder and 22%–25% for symptoms) (all Ps < 0.01). Proportions of insomnia cases were significantly higher among participants who completed the survey earlier in the first wave of the pandemic relative to those who completed it later. Risks of insomnia were higher among participants who reported having had COVID-19, who reported greater financial burden, were in confinement for a period of four to five weeks, and living alone or with more than five people in same household. These associations remained significant after controlling for age, sex, and psychological symptoms. Conclusion and relevance Insomnia, anxiety, and depression were very prevalent during the first wave of the COVID-19 pandemic. Public health prevention programs are needed to prevent chronicity and reduce long-term adverse outcomes associated with chronic insomnia and mental health problems.

Objective Many have reported odd dreams during the pandemic. Given that dreams are associated with mental health, understanding these changes could provide crucial information about wellbeing during the pandemic. This study explored associations between COVID-19 and dream recall frequency (DRF), and related social, health, and mental health factors. Methods We conducted a cross-sectional web survey of 19,355 individuals in 14 countries from May to July 2020. We collected data on COVID-19, mental health, sleep and DRF during the pandemic. We performed McNemar Tests to compare low (<3 nights per week) and high DRF (≥3 nights per week) before and during COVID-19 and to evaluate changes in sleep variables segmented by DRF. Chi-square tests were conducted to compare characteristics between low and high DRF. Logistic regression analyses were conducted to examine associations between various independent variables and DRF. Results Reports of high DRF during the pandemic were higher than before the pandemic (P<0.001). Female gender (aOR=1.25, 95% CI 1.10–1.41), nightmares (aOR=4.22, 95% CI 3.45–5.17), sleep talking (aOR= 2.36, 1.73–3.23), sleep maintenance problems (aOR=1.34, 95% CI 1.15–1.56), symptoms of REM sleep behavior disorder (RBD; aOR=1.24, 95% CI 1.09–1.41) and repeated disturbing thoughts (posttraumatic stress disorder (PTSD) symptoms) were associated with high DRF. Age group 55–64 years (aOR=0.69, 95% CI 0.58–0.83) reported less high DRF than younger participants. Unadjusted OR showed associations between depression, anxiety, and DRF; however, in adjusted regression depression (aOR= 0.71, 0.59–0.86) and anxiety (aOR=0.79, 95% CI 0.66–0.94) were negatively associated with high DRF. Conclusion and Relevance DRF was higher than pre-pandemic levels across four continents. DRF was associated with gender and parasomnias like nightmares and RBD symptoms, sleep maintenance problems, PTSD symptoms and negatively associated with depression and anxiety. The results implicate that COVID-19 is reflected in our dreams as an expression of the emotional intensity of the pandemic.

Arterial blood pressure patterns in 12 men with sleep apnea and arterial hypertension were studied at baseline and after 6 months’ therapy with nasal continuous positive airway pressure (nCPAP). Preexisting antihypertensive medication was discontinued 1 week before baseline measurements. Weight did not change during the study period; body mass index was 29.3 (range, 25.4–38.5) vs. 29.3 (25.0–38.5). During therapy the apnea index decreased from 58 (range 30–73) to 2 (range 0–7) apneic episodes per hour (p < 0.01). Intra-arterial systolic (BP sys.) and diastolic (BP dias.) blood pressure and heart rate decreased during therapy (p < 0.001). Mean values ± 95 % confidence intervals were as follows: BP sys., 147.1 ( ± 1.6) mm Hg vs. 126.4 ( ± 1.5) mm Hg; BP dias., 81.6 ( ± 0.8) mm Hg vs. 69.4 ( ± 0.6) mm Hg; heart rate, 68.8 ( ± 0.7) beats/min vs. 65.4 ( ± 0.7) beats/min. Furthermore, the variability of these parameters decreased during therapy: variability BPsys.,53.8( ± 1.1) mm Hg vs. 25.6 ( ± 1.1) mm Hg; variability BP dias., 35.6 ( ± 0.7) mm Hg vs. 17.9 ( ± 0.7) mm Hg; variability of heart rate, 28.1 ( ± 0.7) beats/min vs. 14.9 ( ± 0.7) beats/min (p < 0.001). During treatment we found that blood pressure scores already dropped during the awake phase, with a further decrease during non-REM and REM sleep (p < 0.001). Our results, which demonstrate the reversibility of high blood pressure upon treatment of sleep apnea, indicate that sleep apnea can be an etiological factor in hypertension. Sleep apnea should therefore be considered in the differential diagnosis of arterial hypertension.

Ballet dancers are competitive athletes who undergo extreme physical and mental stress and work according to an irregular schedule, with long days of training, rehearsal, and performance. Their most significant potential risks entail physical injury and altered sleep. The elaborate training requirements for ballet dancers do not allow regular chronobiological patterns or a normal sleep-wake rhythm. Our aim was to investigate the sleep-wake rhythm and sleep quality during rehearsal phases prior to a ballet premiere. We used wrist actigraphy and sleep diaries for a period of 67 days before the ballet premiere performance to study 24 classical ballet dancers. We likewise applied the Epworth Sleepiness Score (ESS), Pittsburgh Sleep Quality Index (PSQI), SF-12 Quality of life Assessment, and d2 Test of Attention to assess quality of sleep, aspects of cognitive performance, and health status. We found significant reduction in sleep duration, from 418+/-43 min to 391+/-42 min, and sleep efficiency, from 81+/-4% to 79+/-5%, over the 67-day course of the rehearsal. We also found a decline in time in bed and an increase in wakefulness after sleep onset. Sleep onset latency did not change. However, the changes in sleep as documented by actigraphy were not reflected by the subjective data of the sleep diaries and sleep scores. As a result of the facts that total sleep efficiency and sleep duration values were already lower than usual for the dancers' age group at the beginning of the study and that mental acuity, concentration, and speed were likewise impaired, we observed exacerbated health deterioration in terms of sleep deprivation in ballet dancers during preparation for a premier. We conclude that individual activity-rest schedules, including daytime naps, may be helpful, especially during the stressful training and rehearsal experienced prior to ballet premieres.

Study Objectives Individual circadian type is a ubiquitous trait defining sleep, with eveningness often associated with poorer sleep and mental health than morningness. However, it is unknown whether COVID-19 pandemic has differentially affected sleep and mental health depending on the circadian type. Here, the differences in sleep and mental health between circadian types are examined globally before and during the COVID-19 pandemic. Methods The sample collected between May and August 2020 across 12 countries/regions consisted of 19,267 adults with information on their circadian type. Statistical analyses were performed by using Complex Sample procedures, stratified by country and weighted by the number of inhabitants in the country/area of interest and by the relative number of responders in that country/area. Results Evening-types had poorer mental health, well-being, and quality of life or health than other circadian types during the pandemic. Sleep-wake schedules were delayed especially on working days, and evening-types reported an increase in sleep duration. Sleep problems increased in all circadian types, but especially among evening-types, moderated by financial suffering and confinement. Intermediate-types were less vulnerable to sleep changes, although morningness protected from most sleep problems. These findings were confirmed after adjusting for age, sex, duration of the confinement or socio-economic status during the pandemic. Conclusions These findings indicate an alarming increase in sleep and mental health problems, especially among evening-types as compared to other circadian types during the pandemic.

The high prevalence of sleep-related breathing disorders demands the development of ambulatory recording devices that can handle data with a high degree of selectivity and are easy to use and to interpret. A digital device based on the recording of heart rate and breathing sounds was developed. Patients with sleep-related breathing disorders can be preselected before they undergo sleep laboratory investigations. Treatment control can be achieved ambulatory, having an initial recording.