Harbingers of Hope: Scientists and the Pursuit of World Peace.

The ongoing wars in many regions-such as the conflict between Israel and Hamas-as well as the effects of war on communities, social services, and mental health are covered in this special editorial. This article emphasizes the need for international efforts to promote peace, offer humanitarian aid, and address the mental health challenges faced by individuals and communities affected by war and violence.

Bright light exposure during simulated night work improves cognitive flexibility.

Night work leads to sleepiness and reduced vigilant attention during work hours, and bright light interventions may reduce such effects. It is also known that total sleep deprivation impairs cognitive flexibility as measured by reversal learning tasks. Whether night work impairs reversal learning task performance or if bright light can mitigate reversal learning deficits during night work is unclear. In this counterbalanced crossover study (ClinicaTrials.gov Identifier NCT03203538), young healthy individuals completed a reversal learning task twice during each of three consecutive simulated night shifts (23:00-07:00 h). The night shifts were performed in a laboratory under a full-spectrum (4000 K) bright light (~900 lx) and a standard light (~90 lx) condition. Reversal learning task performance was reduced towards the end of the night shifts (04:50 h), compared to the first part of the night shifts (00:20 h) in both light conditions. However, with bright light, the reversal learning task performance improved towards the end of the night shifts, compared to standard light. The study shows that bright light may mitigate performance deficits on a reversal learning task during night work and implies that bright light interventions during night work may be beneficial not only for vigilant attention but also for cognitive flexibility.

Sleep Homeostasis and Night Work: A Polysomnographic Study of Daytime Sleep Following Three Consecutive Simulated Night Shifts.

PURPOSE: Millions of people work at times that overlap with the habitual time for sleep. Consequently, sleep often occurs during the day. Daytime sleep is, however, characterized by reduced sleep duration. Despite preserved time spent in deep NREM sleep (stage N3), daytime sleep is subjectively rated as less restorative. Knowledge on how night work influences homeostatic sleep pressure is limited. Therefore, we aimed to explore the effect of three consecutive simulated night shifts on daytime sleep and markers of sleep homeostasis. PATIENTS AND METHODS: We performed continuous EEG, EMG and EOG recordings in the subjects' home setting for one nighttime sleep opportunity, and for the daytime sleep opportunities following three consecutive simulated night shifts. RESULTS: For all daytime sleep opportunities, total sleep time was reduced compared to nighttime sleep. While time spent in stage N3 was preserved, sleep pressure at sleep onset, measured by slow wave activity (1-4 Hz), was higher than nighttime sleep and higher on day 3 than on day 1 and 2. Elevated EEG power during daytime sleep was sustained through 6 h of time in bed. Slow wave energy was not significantly different from nighttime sleep after 6 h, reflecting a less efficient relief of sleep pressure. CONCLUSION: Adaptation to daytime sleep following three consecutive simulated night shifts is limited. The increased homeostatic response and continuation of sleep pressure relief even after 6 h of sleep, are assumed to reflect a challenge for appropriate homeostatic reduction to occur.

A randomized controlled trial on the effect of blue-blocking glasses compared to partial blue-blockers on melatonin profile among nulliparous women in third trimester of the pregnancy.

OBJECTIVE: In pregnancy melatonin regulates circadian rhythms, induce sleep, and has a neuroprotective positive effect on fetal development. Artificial blue light in the evening delays and suppresses melatonin production. Thus, we investigated the effect of blocking blue light on the melatonin profile. METHODS: A randomized controlled trial (n=30 blue-blocking glasses vs. n=30 control glasses with partial blue-blocking effect) including healthy nulliparous pregnant women in the beginning of the third trimester. Salivary melatonin and subjective sleep were measured before and after two weeks of intervention/control condition. Saliva was sampled at 30-min intervals from 3 h before normal bedtime. Melatonin onset was set at 4.0 pg/ml. RESULTS: Due to missing data melatonin onset was estimated for 47 participants. At posttreatment, melatonin onset advanced by 28 min in the blue-blocking group compared with the control condition (p=.019). Melatonin levels were significantly higher, favoring the blue-blocking glass condition, at clock time 20:00, 21:00 and 22:00 h, and for sample number 3 and 4. The phase angle (time interval) between melatonin onset and sleep bedtime and sleep onset time increased within the blue blocking group (+45 min and +41 min, respectively), but did not reach statistical significance compared to control condition (+13 min and +26 min, respectively). CONCLUSION: Blocking blue light in the evening had a positive effect on the circadian system with an earlier onset and rise of melatonin levels in healthy nulliparous pregnant women. This demonstrated the effectiveness and feasibility of a simple non-pharmacological chronobiological intervention during pregnancy.

A randomized controlled trial on the effects of blue-blocking glasses compared to partial blue-blockers on sleep outcomes in the third trimester of pregnancy.

OBJECTIVE: Sleep disturbances are common in pregnancy. Blocking blue light has been shown to improve sleep and may be a suitable intervention for sleep problems during pregnancy. The present study investigated the effects of blue light blocking in the evening and during nocturnal awakenings among pregnant women on primary sleep outcomes in terms of total sleep time, sleep efficiency and mid-point of sleep. METHODS: In a double-blind randomized controlled trial, 60 healthy nulliparous pregnant women in the beginning of the third trimester were included. They were randomized, using a random number generator, either to a blue-blocking glass intervention (n = 30) or to a control glass condition constituting partial blue-blocking effect (n = 30). Baseline data were recorded for one week and outcomes were recorded in the last of two intervention/control weeks. Sleep was measured by actigraphy, sleep diaries, the Bergen Insomnia Scale, the Karolinska Sleepiness Scale and the Pre-Sleep Arousal Scale. RESULTS: The results on the primary outcomes showed no significant mean difference between the groups at posttreatment, neither when assessed with sleep diary; total sleep time (difference = .78[min], 95%CI = -19.7, 21.3), midpoint of sleep (difference = -8.9[min], 95%CI = -23.7, 5.9), sleep efficiency (difference = -.06[%], 95%CI = -1.9, 1.8) and daytime functioning (difference = -.05[score points], 95%CI = -.33, .22), nor by actigraphy; total sleep time (difference = 13.0[min], 95%CI = -9.5, 35.5), midpoint of sleep (difference = 2.1[min], 95%CI = -11.6, 15.8) and sleep efficiency (difference = 1.7[%], 95%CI = -.4, 3.7). On the secondary outcomes, the Bergen Insomnia Scale, the Karolinska Sleepiness Scale and the Pre-Sleep Arousal Scale the blue-blocking glasses no statistically significant difference between the groups were found. Transient side-effects were reported in both groups (n = 3). CONCLUSIONS: The use of blue-blocking glasses compared to partially blue-blocking glasses in a group of healthy pregnant participants did not show statistically significant effects on sleep outcomes. Research on the effects of blue-blocking glasses for pregnant women with sleep-problems or circadian disturbances is warranted. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov (NCT03114072).

The Effects of Pharmacological Treatment of Nightmares: A Systematic Literature Review and Meta-Analysis of Placebo-Controlled, Randomized Clinical Trials.

Nightmares are highly prevalent and distressing for the sufferer, which underlines the need for well-documented treatments. A comprehensive literature review and meta-analysis of the effects of different pharmacological placebo-controlled randomized clinical trials, covering the period up to 1 December 2022, was performed. Searches were conducted in PubMed, Embase, Web of Science, PsychInfo, Cinahl, and Google Scholar, resulting in the identification of 1762 articles, of which 14 met the inclusion criteria: pharmacological intervention of nightmares, based on a placebo-controlled randomized trial published in a European language, reporting outcomes either/or in terms of nightmare frequency, nightmare distress, or nightmare intensity, and reporting sufficient information enabling calculation of effect sizes. Most studies involved the effect of the α1-adrenergic antagonist prazosin in samples of veterans or soldiers suffering from posttraumatic stress disorder. Other medications used were hydroxyzine, clonazepam, cyproheptadine, nabilone, and doxazosin. The vast majority of studies were conducted in the USA. The studies comprised a total of 830 participants. The Clinician-Administered PTSD Scale was the most frequently used outcome measure. The results showed an overall effect size of Hedges' g = 0.50 (0.42 after adjustment for publication bias). The synthetic cannabinoid nabilone (one study) showed the highest effect size (g = 1.86), followed by the histamine H1-antagonist hydroxyzine (one study), and prazosin (10 studies), with effect sizes of g = 1.17 and g = 0.54, respectively. Findings and limitations are discussed, and recommendations for future studies are provided.

Time-of-Day Effects in Resting-State Functional Magnetic Resonance Imaging: Changes in Effective Connectivity and Blood Oxygenation Level Dependent Signal.

Introduction: In the light of the ongoing replication crisis in the field of neuroimaging, it is necessary to assess the possible exogenous and endogenous factors that may affect functional magnetic resonance imaging (fMRI). The current project investigated time-of-day effects in the spontaneous fluctuations (<0.1 Hz) of the blood oxygenation level dependent (BOLD) signal. Method: Using data from the human connectome project release S1200, cross-spectral density dynamic causal modeling (DCM) was used to analyze time-dependent effects on the hemodynamic response and effective connectivity parameters. The DCM analysis covered three networks, namely the default mode network, the central executive network, and the saliency network. Hierarchical group-parametric empirical Bayes (PEB) was used to test varying design-matrices against the time-of-day model. Results: Hierarchical group-PEB found no support for changes in effective connectivity, whereas the hemodynamic parameters exhibited a significant time-of-day dependent effect, indicating a diurnal vascular effect that might affect the measured BOLD signal in the absence of any diurnal variations of the underlying neuronal activations and effective connectivity. Conclusion: We conclude that these findings urge the need to account for the time of data acquisition in future MRI studies and suggest that time-of-day dependent metabolic variations contribute to reduced reliability in resting-state fMRI studies.

In the twilight zone: An epidemiological study of sleep-related hallucinations.

BACKGROUND: Few studies have investigated hallucinations that occur at the onset/offset of sleep (called hypnagogic/hypnopompic hallucinations; HHHs), despite the fact that their prevalence in the general population is reported to be higher than the prevalence of daytime hallucinations. We utilized data from an epidemiological study to explore the prevalence of HHHs in various modalities. We also investigated phenomenological differences between sleep-related (HHHs) and daytime hallucinations in the auditory modality. We hypothesized that individuals with only HHHs would not differ from controls on a range of mental health and wellbeing measures, but that if they occur together with daytime hallucinations will pose a greater burden on the individual experiencing them. We also hypothesize that HHHs are qualitatively different (i.e. less severe) from daytime hallucinations. METHODS: This study utilized data from a cross-sectional epidemiological study on the prevalence of hallucinations in the Norwegian general population. The sample (n = 2533) was divided into a control group without hallucinations (n = 2303), a group only experiencing sleep-related hallucinations (n = 62), a group only experiencing daytime hallucinations (n = 57), and a group experiencing both sleep-related as well as daytime hallucinations (n = 111). Prevalence rates were calculated and groups were compared using analyses of variance and chi-square tests where applicable. RESULTS: The prevalence for HHHs in the auditory domain was found to be 6.8%, whereas 12.3% reported multimodal HHHs, and 32.2% indicated out-of-body experiences at the onset/offset of sleep. Group comparisons of hallucinations in the auditory modality showed that individuals that experienced only auditory HHHs scored significantly (p < 0.05) lower than those who also experienced daytime auditory hallucinations on a range of variables including mental health, anxiety, childhood happiness, and wellbeing. In addition, individuals with only auditory HHHs reported significantly (p < 0.05) less frequent hallucinations, less disturbing hallucinations, more neutral (in terms of content) hallucinations, hallucinations with less influence over their behavior, and less hallucination-related interference with social life compared to those individuals that experience daytime hallucinations. We also found that purely auditory HHHs had a significantly higher age of first onset of hallucinations than the purely daytime and the combined daytime and auditory HHHs groups (28.2 years>20.9 > 19.1). CONCLUSIONS: Sleep-related hallucinations are common experiences in the general population, with the auditory modality being the least common. They occur mostly in combination with daytime hallucinations. However, some individuals (2.4%) experience only (auditory) sleep-related hallucinations and this group can be seen as more closely related, on a range of health-related factors, to non-hallucinating individuals than individuals who experience daytime hallucinations. Finally, there is a clear need for more research in this field, and ideas for future studies are presented.

Sleep, evening light exposure and perceived stress in healthy nulliparous women in the third trimester of pregnancy.

OBJECTIVE: Sleep disturbances are common in pregnancy, and the prevalence increases during the third trimester. The aim of the present study was to assess sleep patterns, sleep behavior and prevalence of insomnia in pregnant women in the third trimester, by comparing them to a group of non-pregnant women. Further, how perceived stress and evening light exposure were linked to sleep characteristics among the pregnant women were examined. METHODS: A total of 61 healthy nulliparous pregnant women in beginning of the third trimester (recruited from 2017 to 2019), and 69 non-pregnant women (recruited in 2018) were included. Sleep was monitored by actigraphy, sleep diaries and the Bergen Insomnia Scale. The stress scales used were the Relationship Satisfaction Scale, the Perceived Stress Scale and the Pre-Sleep Arousal Scale. Total white light exposure three hours prior to bedtime were also assessed. RESULTS: The prevalence of insomnia among the pregnant women was 38%, with a mean score on the Bergen Insomnia Scale of 11.2 (SD = 7.5). The corresponding figures in the comparing group was 51% and 12.3 (SD = 7.7). The pregnant women reported lower sleep efficiency (mean difference 3.8; 95% CI = 0.3, 7.3), longer total sleep time derived from actigraphy (mean difference 59.0 minutes; 95% CI = 23.8, 94.2) and higher exposure to evening light (mean difference 0.7; 95% CI = 0.3, 1.2), compared to the non-pregnant group. The evening light exposure was inversely associated with total sleep time derived from actigraphy (B = -8.1; 95% CI = -14.7, -1.5), and an earlier midpoint of sleep (B = -10.3, 95% CI = -14.7, -5.9). Perceived stressors were unrelated to self-reported and actigraphy assessed sleep. CONCLUSION: In healthy pregnant participants sleep in the third trimester was preserved quite well. Even so, the data suggest that evening light exposure was related to shorter sleep duration among pregnant women.

Effect of Dietary Nitrate Supplementation on Sleep in Chronic Obstructive Pulmonary Disease Patients.

PURPOSE: Poor sleep quality in chronic obstructive pulmonary disease (COPD) is a result of oxygen desaturation secondary to compromised lung function. Nitrate supplementation with dietary beetroot juice is known to elevate plasma nitrate and to increase the efficiency of oxygen utilization in non-COPD individuals; whether it is of therapeutic benefit for sleep quality in COPD has not been reported. PATIENTS AND METHODS: In a counterbalanced within-subjects design involving 15 COPD patients as subjects, the subjects consumed either beetroot juice containing nitrate (BJ; ∼6.2 mmol NO3 -) or placebo (NO3 - -depleted juice) immediately before a night of polysomnographic monitoring. Nitrate was measured in plasma collected immediately after waking. RESULTS: While BJ consumption had no effect on the amount of time spent in any sleep stages, wake-to-N2 transitions and direct wake-to-rapid eye movement sleep (REMS) transitions, hallmarks of disordered sleep, were less frequent on the BJ night than on the placebo night. In the last two hours of the BJ night, percent time in REMS increased and delta power during deep (N3) non-REMS decreased, relative to the placebo night. Collectively, the reduced frequency of atypical transitions and the normalization of non-REMS/REMS dynamics after BJ are indicative of an improvement of sleep quality. BJ also resulted in sustained elevation of peripheral oxygen saturation (SpO2), during episodes of wake after sleep onset. Plasma nitrate was elevated nearly tenfold on the morning after BJ relative to placebo. CONCLUSION: BJ has a normalizing effect on disordered sleep in COPD, which may be related to improved oxygen delivery. CLINICAL TRIAL REGISTRATION: The activities of the Regional Committees for Medical and Health Research Ethics (REC) are founded on the Norwegian law on research ethics and medical research. This study was approved by NTNU/REK midt, Det medisinske fakultet, Postboks 8905, 7491 Trondheim (REK midt 2016/1360).

Predictors and correlates of lifetime and persistent non-suicidal self-injury and suicide attempts among adult survivors of childhood sexual abuse.

Background: Childhood sexual abuse (CSA) is a well-established risk factor for non-suicidal self-injury (NSSI) and suicide attempts (SA); still few studies have examined predictors of individual differences in NSSI/SA amongst CSA survivors. Objective: To examine predictors of NSSI and SA among adult CSA-survivors. Methods: In a sample of 516, primarily female adult CSA-survivors recruited from support centres for sexual abuse survivors in Norway, we examined the role of abuse/perpetrator characteristics, and the degree/severity of exposure to other types of childhood maltreatment (cumulative childhood maltreatment; CCM), as predictors of lifetime NSSI and SA. In a subsample of 138 individuals responding to follow-up waves two- and four years later, these same distal factors, as well as previous NSSI and proximal factors in the form of symptoms of mental health disorders (posttraumatic stress, anxiety, depression, sleep disturbances, and eating disorders), relational problems, and perceived social support, were examined as predictors of persistent NSSI. Finally, those attempting new SA during the follow-up period were compared to those who did not on these variables. Results: Higher CCM scores and having had an unknown perpetrator positively predicted lifetime NSSI scores. Higher CCM scores, violent abuse, and having had an unknown perpetrator predicted lifetime SA. Higher CCM scores, previous NSSI, having had a known perpetrator, as well as higher depression-, anxiety- and eating disorder scores, positively predicted persistent NSSI during the four-year follow-up period. Compared to those with no new SA, those reporting new SA during the follow-up period had higher CCM, lifetime NSSI, mental health symptoms and relational problem scores, lower perceived social support scores, and were more likely to have done a past SA and to have experienced abuse involving physical violence. Conclusions: A broad range of both distal and proximal factors should be assessed as potential predictors of NSSI and SA among adult CSA-survivors.

Antecedentes: El abuso sexual infantil (CSA por sus siglas en inglés) es un factor de riesgo bien establecido para las autolesiones no suicidas (NSSI por sus siglas en inglés) y los intentos suicidas (SA por sus siglas en inglés); aun así, pocos estudios han examinado los predictores de las diferencias individuales en NSSI/SA en los sobrevivientes de CSA. Objetivo: Examinar los predictores de NSSI y SA entre adultos sobrevivientes de CSA.Métodos: En una muestra de 516, primariamente mujeres adultas sobrevivientes de CSA reclutadas de centros de apoyo para sobrevivientes de abuso sexual en Noruega, examinamos el rol de las características del abuso/perpetrador y el grado/severidad de la exposición a otros tipos de maltrato infantil (maltrato acumulativo infantil; CCM por sus siglas en ingles), como predictores de NSSI y SA en la vida. En una submuestra de 138 individuos que respondieron a las etapas de seguimiento dos y cuatro años después, se examinaron como predictores de NSSI persistente, estos mismos factores distales, así como NSSI previos y factores proximales en la forma de síntomas de trastornos de salud mental (estrés postraumático, ansiedad, depresión, trastornos del sueño y trastornos de la conducta alimentaria), problemas relacionales, y apoyo social percibido. Finalmente, se compararon en estas variables los que intentaron un nuevo SA durante el periodo de seguimiento con los que no lo hicieron.Resultados: Puntajes más altos de CCM y haber tenido un perpetrador desconocido, predijeron positivamente puntajes de NSSI en la vida. Puntajes de CCM más altos, abuso violento y haber tenido un perpetrador desconocido predijeron el SA en la vida. Los puntajes más altos de CCM, NSSI previos, haber tenido un perpetrador conocido, así como puntajes más altos de depresión, ansiedad y trastornos alimentarios, predijeron positivamente NSSI persistente durante el periodo de seguimiento de 4 años. Comparado con los individuos sin nuevos SA, los que reportaron SA nuevos durante el periodo de seguimiento tenían puntajes más altos de CCM, NSSI en la vida, síntomas de salud mental y problemas relacionales, puntajes más bajos de apoyo social percibido y tenían más probabilidades de haber realizado SA en el pasado y haber experimentado abuso que involucraba violencia física.Conclusiones: Se debe evaluar una amplia gama de factores distales y proximales como posibles predictores de NSSI y SA entre adultos sobrevivientes de CSA.

Alerting and Circadian Effects of Short-Wavelength vs. Long-Wavelength Narrow-Bandwidth Light during a Simulated Night Shift.

Light can be used to facilitate alertness, task performance and circadian adaptation during night work. Novel strategies for illumination of workplaces, using ceiling mounted LED-luminaires, allow the use of a range of different light conditions, altering intensity and spectral composition. This study (ClinicalTrials.gov Identifier NCT03203538) investigated the effects of short-wavelength narrow-bandwidth light (λmax = 455 nm) compared to long-wavelength narrow-bandwidth light (λmax = 625 nm), with similar photon density (~2.8 × 1014 photons/cm2/s) across light conditions, during a simulated night shift (23:00-06:45 h) when conducting cognitive performance tasks. Light conditions were administered by ceiling mounted LED-luminaires. Using a within-subjects repeated measurements study design, a total of 34 healthy young adults (27 females and 7 males; mean age = 21.6 years, SD = 2.0 years) participated. The results revealed significantly reduced sleepiness and improved task performance during the night shift with short-wavelength light compared to long-wavelength light. There was also a larger shift of the melatonin rhythm (phase delay) after working a night shift in short-wavelength light compared to long-wavelength light. Participants' visual comfort was rated as better in the short-wavelength light than the long-wavelength light. Ceiling mounted LED-luminaires may be feasible to use in real workplaces, as these have the potential to provide light conditions that are favorable for alertness and performance among night workers.

Blue-Enriched White Light Improves Performance but Not Subjective Alertness and Circadian Adaptation During Three Consecutive Simulated Night Shifts.

Use of blue-enriched light has received increasing interest regarding its activating and performance sustaining effects. However, studies assessing effects of such light during night work are few, and novel strategies for lighting using light emitting diode (LED) technology need to be researched. In a counterbalanced crossover design, we investigated the effects of a standard polychromatic blue-enriched white light (7000 K; ∼200 lx) compared to a warm white light (2500 K), of similar photon density (∼1.6 × 1014 photons/cm2/s), during three consecutive simulated night shifts. A total of 30 healthy participants [10 males, mean age 23.3 (SD = 2.9) years] were included in the study. Dependent variables comprised subjective alertness using the Karolinska Sleepiness Scale, a psychomotor vigilance task (PVT) and a digit symbol substitution test (DSST), all administered at five time points throughout each night shift. We also assessed dim-light melatonin onset (DLMO) before and after the night shifts, as well as participants' opinion of the light conditions. Subjective alertness and performance on the PVT and DSST deteriorated during the night shifts, but 7000 K light was more beneficial for performance, mainly in terms of fewer errors on the PVT, at the end of the first- and second- night shift, compared to 2500 K light. Blue-enriched light only had a minor impact on PVT response times (RTs), as only the fastest 10% of the RTs were significantly improved in 7000 K compared to 2500 K light. In both 7000 and 2500 K light, the DLMO was delayed in those participants with valid assessment of this parameter [n = 20 (69.0%) in 7000 K light, n = 22 (78.6%) in 2500 K light], with a mean of 2:34 (SE = 0:14) and 2:12 (SE = 0:14) hours, respectively, which was not significantly different between the light conditions. Both light conditions were positively rated, although participants found 7000 K to be more suitable for work yet evaluated 2500 K light as more pleasant. The data indicate minor, but beneficial, effects of 7000 K light compared to 2500 K light on performance during night work. Circadian adaptation did not differ significantly between light conditions, though caution should be taken when interpreting these findings due to missing data. Field studies are needed to investigate similar light interventions in real-life settings, to develop recommendations regarding illumination for night workers. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT03203538.

Validation of sleep stage classification using non-contact radar technology and machine learning (Somnofy®).

OBJECTIVE: To validate automatic sleep stage classification using deep neural networks on sleep assessed by radar technology in the commercially available sleep assistant Somnofy® against polysomnography (PSG). METHODS: Seventy-one nights of overnight sleep in healthy individuals were assessed by both PSG and Somnofy at two different institutions. The Somnofy unit was placed in two different locations per room (nightstand and wall). The sleep algorithm was validated against PSG using a 25-fold cross validation technique, and performance was compared to the inter-rater reliability between the PSG sleep scored by two independent sleep specialists. RESULTS: Epoch-by-epoch analyses showed a sensitivity (accuracy to detect sleep) and specificity (accuracy to detect wake) for Somnofy of 0.97 and 0.72 respectively, compared to 0.99 and 0.85 for the PSG scorers. The sleep stage differentiation for Somnofy was 0.75 for N1/N2, 0.74 for N3 and 0.78 for R, whilst PSG scorers ranged between 0.83 and 0.96. The intraclass correlation coefficient revealed excellent and good reliability for total sleep time and sleep efficiency, while sleep onset and R latency had poor agreement. Somnofy underestimated total wake time by 5 min and N1/N2 by 3 min. N3 was overestimated by 4 min and R by 3 min. Results were independent of institution and sensor location. CONCLUSION: Somnofy showed a high accuracy staging sleep in healthy individuals and has potential to assess sleep quality and quantity in a sample of healthy, mostly young adults. More research is needed to examine performance in children, older individuals and those with sleep disorders.

Cognitive function and brain plasticity in a rat model of shift work: role of daily rhythms, sleep and glucocorticoids.

Many occupations require operations during the night-time when the internal circadian clock promotes sleep, in many cases resulting in impairments in cognitive performance and brain functioning. Here, we use a rat model to attempt to identify the biological mechanisms underlying such impaired performance. Rats were exposed to forced activity, either in their rest-phase (simulating night-shift work; rest work) or in their active-phase (simulating day-shift work; active work). Sleep, wakefulness and body temperature rhythm were monitored throughout. Following three work shifts, spatial memory performance was tested on the Morris Water Maze task. After 4 weeks washout, the work protocol was repeated, and blood and brain tissue collected. Simulated night-shift work impaired spatial memory and altered biochemical markers of cerebral cortical protein synthesis. Measures of daily rhythm strength were blunted, and sleep drive increased. Individual variation in the data suggested differences in shift work tolerance. Hierarchical regression analyses revealed that type of work, changes in daily rhythmicity and changes in sleep drive predict spatial memory performance and expression of brain protein synthesis regulators. Moreover, serum corticosterone levels predicted expression of brain protein synthesis regulators. These findings open new research avenues into the biological mechanisms that underlie individual variation in shift work tolerance.

Longitudinal Relationships between Perceived Social Support and Symptom Outcomes: Findings from a sample of Adult Survivors of Childhood Sexual Abuse.

INTRODUCTION: Cross-sectional studies have consistently reported an inverse association between perceived social support and the severity of mental health symptoms among adult survivors of childhood sexual abuse (CSA). However, there is a lack of longitudinal studies investigating the bidirectional association between social support and the severity of symptoms among adult CSA-survivors, as well as the role of relational problems in predicting perceived social support and symptom levels over time. The present study addressed these questions in a sample of primarily female CSA-survivors. METHODS: In a three-wave, four-year longitudinal study of 506 CSA-survivors (94.9% women, 5.1% men) recruited from support centers for sexual abuse survivors in Norway, we used cross-lagged panel structural equation modeling to examine the directionality of the longitudinal associations between perceived social support and symptoms of posttraumatic stress, anxiety, depression and insomnia. RESULTS: Cross-lagged panel analyses revealed significant weak reciprocal associations between perceived social support and depression, posttraumatic stress symptoms and anxiety symptoms, but not with insomnia symptoms. The observed effects were partly overlapping and partly inconsistent across the different symptom domains. Relational problems predicted social support cross-sectionally and longitudinally, whereas only cross-sectional associations were found between the relational problems variable and mental health symptoms. Theoretical and clinical implications of the findings are discussed, alongside methodological limitations of the study.

Role of nocturnal light intensity on adaptation to three consecutive night shifts: a counterbalanced crossover study.

OBJECTIVES: To investigate how a standard ceiling mounted light-emitting diode (LED)-based bright light intervention affected alertness and neurobehavioural performance during three consecutive simulated night shifts, and timing of circadian rhythm after the shifts. METHODS: Twenty seven participants (20 females, 21.4±2.1 years; mean±SD) worked three consecutive night shifts (23:00-07:00) under a full-spectrum (4000 K) bright light (900 lx) and a standard light (90 lx) condition in a counterbalanced crossover design (separated by 4 weeks). Subjective alertness (Karolinska Sleepiness Scale) and neurobehavioural performance (Psychomotor Vigilance Task and Digit Symbol Substitution Test) were assessed five times during each shift. Salivary dim-light melatonin onset (DLMO) was assessed before and after the shifts. The simulated night shifts were conducted in a laboratory while the participants slept at home. RESULTS: Subjective alertness and neurobehavioural performance deteriorated during the night shifts in both light conditions. However, bright light significantly reduced alertness and performance decrements as compared with standard light. For a subset of the participants, DLMO was delayed by a mean of 3:17±0:23 (mean±SEM) hours after three night shifts in bright light and by 2:06±0:15 hours in standard light, indicating that bright light causes larger phase delay. CONCLUSION: Bright light improved performance and alertness during simulated night shifts and improved adaptation to night work. Bright light administered by ceiling mounted LED luminaires has the potential to improve adaptation to night work and reduce the risk of accidents and injuries among night workers. TRIAL REGISTRATION NUMBER: NCT03203538.

Blue-blocking glasses as additive treatment for mania: Effects on actigraphy-derived sleep parameters.

Improvement of sleep is a central treatment goal for patients in a manic state. Blue-blocking (BB) glasses as adjunctive treatment hasten overall recovery from mania. This method is an evolvement from dark therapy and builds on the discovery of the blue-light-sensitive retinal ganglion cell that signals daytime to the brain. We report effects of adjunctive BB glasses on actigraphy-derived sleep parameters for manic inpatients as compared to placebo. Hospitalized patients with bipolar disorder in a manic state aged 18-70 years were recruited from five clinics in Norway from February 2012 to February 2015. The participants were randomly allocated to wearing BB glasses or placebo (clear glasses) as an adjunctive treatment from 18:00 to 08:00 hours for seven consecutive nights. Sleep and wake were monitored by actigraphy. From 32 eligible patients, 10 patients in each group qualified for the group analyses. The BB group's mean sleep efficiency was significantly higher at night 5 as compared to the placebo group (92.6% vs. 83.1%, p = .027). The 95% confidence interval (CI) was 89.4%-95.8% in the BB group and 75.9%-90.3% in the placebo group. There were fewer nights of interrupted sleep in the BB group: 29.6% versus 43.8% in the placebo group. The BB group received less-intensive sleep-promoting pharmacological treatment and showed significantly higher sleep efficiency and more consolidated sleep as compared to the placebo group. Our findings suggest sleep-promoting effects through deactivating mechanisms. Adjunctive BB glasses seem to be useful for improving sleep for manic patients in the hospital setting.

Validation of peripheral arterial tonometry as tool for sleep assessment in chronic obstructive pulmonary disease.

Obstructive sleep apnea (OSA) worsens outcomes in Chronic Obstructive Pulmonary Disease (COPD), and reduced sleep quality is common in these patients. Thus, objective sleep monitoring is needed, but polysomnography (PSG) is cumbersome and costly. The WatchPAT determines sleep by a pre-programmed algorithm and has demonstrated moderate agreement with PSG in detecting sleep stages in normal subjects and in OSA patients. Here, we validated WatchPAT against PSG in COPD patients, hypothesizing agreement in line with previous OSA studies. 16 COPD patients (7 men, mean age 61 years), underwent simultaneous overnight recordings with PSG and WatchPAT. Accuracy in wake and sleep staging, and concordance regarding total sleep time (TST), sleep efficiency (SE), and apnea hypopnea index (AHI) was calculated. Compared to the best fit PSG score, WatchPAT obtained 93% sensitivity (WatchPAT = sleep when PSG = sleep), 52% specificity (WatchPAT = wake when PSG = wake), 86% positive and 71% negative predictive value, Cohen's Kappa (κ) = 0.496. Overall agreement between WatchPat and PSG in detecting all sleep stages was 63%, κ = 0.418. The mean(standard deviation) differences in TST, SE and AHI was 25(61) minutes (p = 0.119), 5(15) % (p = 0.166), and 1(5) (p = 0.536), respectively. We conclude that in COPD-patients, WatchPAT detects sleep stages in moderate to fair agreement with PSG, and AHI correlates well.