Sleep-wake Parameters Research Articles

Characterization of sleep disturbance in established rheumatoid arthritis patients: exploring the relationship with central nervous system pain regulation

BackgroundTo characterize sleep disturbance in patients with established rheumatoid arthritis (RA) and explore the relationship between sleep and mechanisms of central nervous system pain regulation.MethodsForty-eight RA participants completed wrist-worn actigraphy monitoring and daily sleep diaries for 14 days to assess sleep-wake parameters. Participants underwent quantitative sensory testing to assess pressure pain thresholds, temporal summation, and conditioned pain modulation. Data were analyzed using descriptive statistics, Spearman’s correlation, and multivariable median regression analyses.ResultsMedian actigraphy and sleep diary derived sleep duration was 7.6 h (interquartile range (IQR) 7.0, 8.2) and 7.1 h (IQR 6.7, 7.6), respectively. Actigraphy based sleep fragmentation (rho = 0.34), wake after sleep onset (rho = 0.36), and sleep efficiency (rho = -0.32) were each related to higher temporal summation values in unadjusted analyses, but these relationships did not persist after controlling for age, body mass index, disease duration, and swollen joint count. No significant relationships were observed between sleep with pressure pain thresholds and conditioned pain modulation.ConclusionActigraphy and sleep diary monitoring are well tolerated in established RA patients. Future investigations should include both subjective and objective assessments, as they may provide information relating to different components and mechanisms.

Promoting sleep health during pregnancy for enhancing women’s health: a longitudinal randomized controlled trial combining biological, physiological and psychological measures, Maternal Outcome after THERapy for Sleep (MOTHERS)

BackgroundSleep is vital for maintaining individuals’ physical and mental health and is particularly challenged during pregnancy. More than 70% of women during the gestational period report insomnia symptoms. Sleep dysfunction in the peripartum increases the risk for a cascade of negative health outcomes during late pregnancy, birth, and postpartum. While psychological interventions are considered the first line treatment for sleep difficulties, they are still scarcely offered during pregnancy and there is a lack of longitudinal research combining psychological and physiological indices.MethodsThe present protocol outlines a randomized controlled trial aimed at testing the long-term effectiveness of an automatized digitalized psychoeducational intervention for insomnia for expectant mothers complaining insomnia symptoms without comorbidity. Outcomes include physiological, hormonal, and subjective indices of maternal psychopathology, stress, and emotional processes, and sleep and wellbeing of the family system.The trial is part of a longitudinal study evaluating expectant mothers from early pregnancy (within the 15th gestational week) to 6-months postpartum through 6 observational phases: baseline (BSL), 6- and 12-weeks from BSL (FU1-FU2), 2-to-4 weeks after delivery (FU3), and 3- and 6-months after delivery (FU4-5). We plan to recruit 38 women without sleep difficulties (Group A) and 76 women with sleep difficulties (Group B). Group B will be randomly assigned to digital psychological control intervention (B1) or experimental psychoeducational intervention targeting insomnia (B2). At 3 time points, an ecological-momentary-assessment (EMA) design will be used to collect data on sleep and emotions (diaries), sleep-wake parameters (actigraphy) and stress reactivity (salivary cortisol). We will also test the DNA methylation of genes involved in the stress response as biomarkers of prenatal poor sleep. Information on partner’s insomnia symptoms and new-borns’ sleep will be collected at each stage.DiscussionThe proposed protocol aims at testing an easily accessible evidence-based psychoeducational intervention for expectant mothers to help them improving sleep, health, and wellbeing in the peripartum. The results could improve the understanding and management of sleep difficulties and peripartum depression.Trial registrationThe study protocol has been registered on 22 April 2024 with ClinicalTrials.gov Protocol Registration and Results System (PRS), ID: NCT06379074. Protocol version: April 23, 2024.

Sleep Disturbance During Post-Traumatic Amnesia and Early Recovery After Traumatic Brain Injury.

After moderate to severe traumatic brain injury (TBI), sleep disturbance commonly emerges during the confused post-traumatic amnesia (PTA) recovery stage. However, the evaluation of early sleep disturbance during PTA, its recovery trajectory, and influencing factors is limited. This study aimed to evaluate sleep outcomes in patients experiencing PTA using ambulatory gold-standard polysomnography (PSG) overnight and salivary endogenous melatonin (a hormone that influences the sleep-wake cycle) assessment at two time-points. The relationships between PSG-derived sleep-wake parameters and PTA symptoms (i.e., agitation and cognitive disturbance) were also evaluated. In a patient subset, PSG was repeated after PTA had resolved to assess the trajectory of sleep disturbance. Participants with PTA were recruited from Epworth HealthCare's inpatient TBI Rehabilitation Unit. Trained nurses administered overnight PSG at the patient bedside using the Compumedics Somté portable PSG device (Compumedics, Ltd., Australia). Two weeks after PTA had resolved, PSG was repeated. On a separate evening, two saliva specimens were collected (at 24:00 and 06:00) for melatonin testing. Results of routine daily hospital measures (i.e., Agitated Behavior Scale and Westmead PTA Scale) were also collected. Twenty-nine patients were monitored with PSG (mean: 41.6 days post-TBI; standard deviation [SD]: 28.3). Patients' mean sleep duration was reduced (5.6 h, SD: 1.2), and was fragmented with frequent awakenings (mean: 27.7, SD: 15.0). Deep, slow-wave restorative sleep was reduced, or completely absent (37.9% of patients). The use of PSG did not appear to exacerbate patient agitation or cognitive disturbance. Mean melatonin levels at both time-points were commonly outside of normal reference ranges. After PTA resolved, patients (n = 11) displayed significantly longer mean sleep time (5.3 h [PTA]; 6.5 h [out of PTA], difference between means: 1.2, p = 0.005). However, disturbances to other sleep-wake parameters (e.g., increased awakenings, wake time, and sleep latency) persisted after PTA resolved. This is the first study to evaluate sleep disturbance in a cohort of patients as they progressed through the early TBI recovery phases. There is a clear need for tailored assessment of sleep disturbance during PTA, which currently does not form part of routine hospital assessment, to suggest new treatment paradigms, enhance patient recovery, and reduce its long-term impacts.

A comparison of sleep-wake patterns among school-age children and adolescents in Hong Kong before and during the COVID-19 pandemic.

The lifestyles change of children and adolescents during the COVID-19 pandemic due to antipandemic measures can affect their sleep health. Existing studies have used convenient samples and focused on the initial months of the pandemic, leaving a knowledge gap on changes in young people's sleep patterns under the "new normal" under COVID-19. As part of a territory-wide epidemiological study in Hong Kong, this cross-sectional study recruited primary and secondary school students by stratified random sampling. Sleep parameters were collected using the structured diagnostic interview for sleep patterns and disorders. We investigated the pandemic's effects on sleep parameters by comparing data of participants recruited pre-COVID and those recruited during COVID using multivariate regression, adjusting for age, sex, household income, seasonality, and presence of mental disorders, and the moderators and mediators of the effects. Between September 1, 2019 and June 2, 2021, 791 primary and 442 secondary school students were recruited and analyzed. Primary school and secondary school participants assessed before COVID had a longer sleep latency on school days (95% confidence interval [CI] = 1.0-5.2 minutes, adjusted P-value = .010; and 95% CI= 3.9-13.0 minutes, adjusted P-value = .004, respectively) and nonschool days (95% CI = 1.7-7.2 minutes, adjusted P-value = .005; 95% CI = 3.4-13.7 minutes, adjusted P-value = .014, respectively). Low household income was a moderator for later bedtime (adjusted P-value = .032) and later sleep onset (adjusted P-value = .043) during nonschool days among secondary school students. Changes associated with COVID have a widespread and enduring effect on the sleep health of school-aged students in Hong Kong. Household income plays a role in adolescent sleep health resilience, and the impact of antiepidemic measures on the health gaps of the youth should be considered. Chau SWH, Hussain S, Chan SSM, etal. A comparison of sleep-wake patterns among school-age children and adolescents in Hong Kong before and during the COVID-19 pandemic. J Clin Sleep Med. 2023;19(4):749-757.

A comparison of agreement between actigraphy and polysomnography for assessing sleep during posttraumatic amnesia.

Sleep disturbance often emerges in the early recovery phase following a moderate to severe traumatic brain injury, known as posttraumatic amnesia. Actigraphy is commonly employed to assess sleep, as it is assumed that patients in posttraumatic amnesia (who display confusion, restlessness, and agitation) would better tolerate this measure over gold-standard polysomnography (PSG). This study evaluated the agreement between PSG and actigraphy for determining (sleep/wake time, sleep efficiency, sleep latency, and awakenings) in patients experiencing posttraumatic amnesia. It also compared the epoch-by-epoch sensitivity, specificity, and accuracy between the Actigraph device's 4 wake threshold settings (low, medium, high, and automatic) to PSG. The sample consisted of 24 inpatients recruited from a traumatic brain injury inpatient rehabilitation unit. Ambulatory PSG was recorded overnight at bedside and a Philips Actiwatch was secured to each patient's wrist for the same period. There were poor correlations between PSG and actigraphy for all parameters (Lin's concordance correlation coefficient = < 0.80). The low threshold displayed the highest correlation with PSG for wake and sleep time, albeit still low. Actigraphy displayed low specificity (ranging from 17.1% to 36.6%). There appears to be a greater disparity between actigraphy and PSG for patients with increased wake time. Actigraphy, while convenient, demonstrated poorer performance in determining sleep-wake parameters in patients with significantly disturbed sleep. Ambulatory PSG can provide a clearer understanding of the extent of sleep disturbances in these patients with reduced mobility during early rehabilitation. Study findings can help design future protocols of sleep assessment during posttraumatic amnesia and optimize treatment. Fedele B, McKenzie D, Williams G, Giles R, Olver J. A comparison of agreement between actigraphy and polysomnography for assessing sleep during posttraumatic amnesia. J Clin Sleep Med. 2022;18(11):2605-2616.

The relationship between autism spectrum and sleep-wake traits.

Autistic children and adults often have sleep disturbances, which may affect their and their family's quality of life. Yet, the relationship between sleep-wake patterns and autism spectrum traits is understudied. Identifying such relationships could lead to future research elucidating common mechanistic underpinnings. Thus, we aimed to determine whether sleep-wake patterns, specifically related to sleep, physical activity, and the daily sleep-wake rhythm (i.e., circadian rhythm), are associated with autism spectrum-related traits. Accelerometer-derived sleep-wake parameters were estimated in individuals with autistic spectrum traits and their family members (N=267). We evaluated autism spectrum traits using the Social Responsiveness Scale (SRS) to assess the presence and severity of social impairment and the Behavior Rating Inventory of Executive Function (BRIEF) to assess executive function. The linear multivariate regression analysis (using SOLAR-Eclipse) showed that in adults, increased core autism spectrum traits and executive dysfunction were associated with disruption of several sleep-wake parameters, particularly related to the daily sleep-wake rhythm, and that executive dysfunction was associated with disrupted sleep quality and level of physical activity. We highlight the interplay between daytime function and disrupted sleep-wake patterns, specifically related to the daily sleep-wake rhythm, that could guide future research into common mechanisms. LAY SUMMARY: Autistic children and adults often report sleep disturbances. To dissect the relationship between a range of autism spectrum traits and sleep-wake patterns, we assessed social interaction and executive function in participants who also wore actimetry watches on their wrists to assess their sleep-wake patterns. We found that increased impairments in social and executive function occurred with increased sleep-wake disturbances, particularly those related to the circadian rhythm, suggesting that these perturbations/disruptions in the sleep-wake cycle could be connected to autism spectrum traits.

Understanding the Associations of Prenatal Androgen Exposure on Sleep Physiology, Circadian Proteins, Anthropometric Parameters, Hormonal Factors, Quality of Life, and Sex Among Healthy Young Adults: Protocol for an International, Multicenter Study.

BackgroundThe ratio of the second finger length to the fourth finger length (2D:4D ratio) is considered to be negatively correlated with prenatal androgen exposure (PAE) and positively correlated with prenatal estrogen. Coincidentally, various brain regions are sensitive to PAE, and their functions in adults may be influenced by the prenatal actions of sex hormones.ObjectiveThis study aims to assess the relationship between PAE (indicated by the 2D:4D ratio) and various physiological (sex hormone levels and sleep-wake parameters), psychological (mental health), and sexual parameters in healthy young adults.MethodsThis study consists of two phases. In phase 1, we will conduct a survey-based study and anthropometric assessments (including 2D:4D ratio and BMI) in healthy young adults. Using validated questionnaires, we will collect self-reported data on sleep quality, sexual function, sleep chronotype, anxiety, and depressive symptoms. In phase 2, a subsample of phase 1 will undergo polysomnography and physiological and genetic assessments. Sleep architecture data will be obtained using portable polysomnography. The levels of testosterone, estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, prolactin, melatonin, and circadian regulatory proteins (circadian locomotor output cycles kaput [CLOCK], timeless [TIM], and period [PER]) and the expression levels of some miRNAs will be measured using blood samples. The rest and activity cycle will be monitored using actigraphy for a 7-day period.ResultsIn Poland, 720 participants were recruited for phase 1. Among these, 140 completed anthropometric measurements. In addition, 25 participants joined and completed phase 2 data collection. Recruitment from other sites will follow.ConclusionsFindings from our study may help to better understand the plausible role of PAE in sleep physiology, mental health, and sexual quality of life in young adults.International Registered Report Identifier (IRRID)DERR1-10.2196/29199

Low-Power Status Updates via Sleep-Wake Scheduling

We consider the problem of optimizing the freshness of status updates that are sent from a large number of low-power sources to a common access point. The source nodes utilize carrier sensing to reduce collisions and adopt an asynchronized sleep-wake scheduling strategy to achieve a target network lifetime (e.g., 10 years). We use <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">age of information</i> (AoI) to measure the freshness of status updates, and design sleep-wake parameters for minimizing the weighted-sum peak AoI of the sources, subject to per-source battery lifetime constraints. When the sensing time (i.e., the time duration of carrier sensing) is zero, this sleep-wake design problem can be solved by resorting to a two-layer nested convex optimization procedure; however, for positive sensing times, the problem is non-convex. We devise a low-complexity solution to solve this problem and prove that, for practical sensing times that are short, the solution is within a small gap from the optimum AoI performance. When the mean transmission time of status-update packets is unknown, we devise a reinforcement learning algorithm that adaptively performs the following two tasks in an “efficient way”: a) it learns the unknown parameter, b) it also generates efficient controls that make channel access decisions. We analyze its performance by quantifying its “regret”, i.e., the sub-optimality gap between its average performance and the average performance of a controller that knows the mean transmission time. Our numerical and NS-3 simulation results show that our solution can indeed elongate the batteries lifetime of information sources, while providing a competitive AoI performance.

Social Jetlag and Excessive Daytime Sleepiness from a Sample of Russian Children and Adolescents.

PurposeInsufficient nocturnal sleep is a primary source of excessive daytime sleepiness. Most previous research has focused on the disparity between sleep demands and study start times in adolescents. Fewer studies have focused on elementary schoolchildren. We hypothesize that late sleep timing is connected to excessive daytime sleepiness in a sample of Russian children and adolescents. The major goals of our study were to evaluate excessive daytime sleepiness in Russian schoolchildren and adolescents using the Russian version of the Pediatric Daytime Sleepiness Scale (PDSS) and to estimate its relationship with sleep-wake parameters using the Munich Chronotype Questionnaire (MCTQ).Materials and MethodsStudent subjects were from public educational facilities in the Republic of Karelia. They completed both the PDSS and the Munich Chronotype Questionnaire to estimate sleep parameters and chronotype (MSFsc). Five hundred and eleven students provided data for the PDSS and sleep-wake variables, and 479 for the full MCTQ data.ResultsThe overall prevalence of Excessive Daytime Sleepiness (EDS) in our sample was 18%. The total PDSS score was inversely correlated with sleep length on school nights and was independent of respondents’ sex. Higher PDSS scores were associated with later bedtimes on school days and free days, and shorter sleep duration on school days. Late chronotype and more pronounced social jetlag were both positively correlated with high PDSS scores. A negative correlation was found between chronotype and the duration of the sleep period on weekdays (p < 0.001) and a positive correlation was found on weekends (p < 0.001). Longer average sleep duration was positively related to less daytime sleepiness.ConclusionThis study suggests that excessive daytime sleepiness is chronotype-dependent. School start times could be shifted to a later hour to prolong sleep and reduce EDS.

Characterization of pharmaco-EEG fingerprint and sleep-wake profiles of Lavandula angustifolia Mill. essential oil inhalation and diazepam administration in rats

Ethnopharmacological relevanceLavandula angustifolia Mill. Essential oil (Lavender EO) has a long history of medicinal use and is particularly claimed to possess anxiolytic and sedative properties. Lavender EO aromatherapy has been used to reduce distress and improve insomnia naturally. Increasing evidence appeared to show similarities between the effects of lavender EO and the anxiolytic drugs, benzodiazepines. However, its effects on sleep-wake and electrical brain patterns in comparison to that of the standard anxiolytic, diazepam, remained to be explored. Aim of the studyThe aim of this work was to investigate electroencephalography (EEG) profiles and sleep-pattern elicited by lavender EO inhalation compared to that of diazepam, a standard anxiolytic drug in in vivo rat model. Materials and methodsAdult male Wistar rats were anesthetized for electrode implantation on the frontal and parietal skulls. EEG signals were recorded for 180 min following intraperitoneal injection of diazepam (10 mg/kg) or during continuous inhalation of lavender EO (200 μL) or distilled water (control). Fast Fourier transform was used for the analyses of EEG power spectra and sleep-wake parameters. ResultsDuring a 30–60 min period, diazepam and lavender EO significantly increased frontal powers of 0.78–45.31 and 7.03–18.36 Hz, respectively. Both treatments also increased parietal powers with lower magnitudes of significant change. Significant increases in some frequency ranges remained until a 60–90 min period. Sleep-wake analyses also revealed that diazepam significantly reduced time spent in wake, increased time spent in non-rapid eye movement (NREM), increased episode duration of NREM, decreased numbers of wake episode and decreased rapid eye movement (REM) sleep latency. On the other hand, lavender EO only significantly decreased wake episodes and latency to REM sleep. Lavender EO inhalation reduced numbers of wake episode but maintain normal time spent in wake, NREM and REM sleeps. ConclusionsThese findings might suggest beneficial and distinct anxiolytic-like effects of lavender EO for sleep enhancing purposes.

Sleep-wake characteristics, daytime sleepiness, and glycemia in young adults with type 1 diabetes.

The purpose of this study was to describe objective sleep-wake characteristics and glycemia over 7-14 days in young adults with type 1 diabetes. In addition, person-level associations among objective sleep-wake characteristics (total sleep time, sleep variability, and sleep fragmentation index), daytime sleepiness, and glycemia (glycemic control and glucose variability) were examined. In this cross-sectional study, objective sleep-wake characteristics were measured via actigraphy and glucose variability via continuous glucose monitoring over 6-14 days. At baseline, participants completed the Psychomotor Vigilance Test, the Trail Making Test, and questionnaires on daytime sleepiness, sleep quality, and sleep disturbance including sleep diaries. Forty-six participants (mean age, 22.3 ± 3.2 years) wore a wrist actigraph and underwent continuous glucose monitoring concurrently for 6-14 days. Greater sleep variability was directly associated with greater glucose variability (mean of daily differences; r = .33, P = .036). Higher daytime sleepiness was directly associated with greater glucose variability (mean of daily differences; r = .50, P = .001). The association between sleep variability and glucose variability (mean of daily differences) was no longer significant when accounting for daytime sleepiness and controlling for type 1 diabetes duration (P > .05). A higher sleep fragmentation index was associated with greater glucose variability (B = 1.27, P = .010, pr2 = 0.40) after controlling for type 1 diabetes duration and accounting for higher daytime sleepiness. Sleep-wake variability, sleep fragmentation, daytime sleepiness, and the associations with glycemia are new dimensions to consider in young adults with type 1 diabetes. Sleep habits in this population may explain higher glucose variability, and optimizing sleep may improve overall diabetes management. Griggs S, Hickman RL Jr, Strohl KP, Redeker NS, Crawford SL, Grey M. Sleep-wake characteristics, daytime sleepiness, and glycemia in young adults with type 1 diabetes. J Clin Sleep Med. 2021;17(9):1865-1874.

024 Quiescent Wakefulness: Characterising the Impact of Oxytocin on Sleep-Wake Behaviour in Male and Female Rats

Abstract Introduction Oxytocin is a versatile hypothalamic neuropeptide involved in diverse neurobehavioural processes. Since oxytocin can elicit anxiolytic and serenic effects, one could hypothesise that oxytocin should prime the brain for sleep and promote hypnogenesis. However, based on the social salience hypothesis—that oxytocin promotes prosocial behaviour and directs attention toward social stimuli—one could also posit that oxytocin should promote wakefulness. At present, little research has comprehensively characterised the effect of oxytocin on sleep-wake behaviour and no explanation to reconcile these two seemingly competing hypotheses has been proposed. Methods This study investigated the effects of oxytocin on sleep-wake outcomes using radiotelemetry-based polysomnography in adult male and female Wistar rats. Oxytocin was administered via the intraperitoneal (IP; 0.1, 0.3 and 1 mg/kg) and intranasal (IN; 0.06, 1, 3 mg/kg) routes. Caffeine (IP and IN; 10 mg/kg) was also administered as a wake-promoting positive control. Additionally, pre-treatment with the oxytocin receptor (OTR) antagonist L-368,899 (IP; 5 mg/kg) and vasopressin 1a receptor (V1aR) antagonist SR49059 (IP; 1 mg/kg) followed by oxytocin (IP; 1 mg/kg) was conducted to determine which receptor(s) mediated sleep-wake effects of oxytocin. Results In both male and female rats, IP oxytocin produced dose-dependent effects on sleep-wake behaviour. Specifically, oxytocin initially promoted quiescent wakefulness (a restful but conscious state) at the cost of reducing both active wakefulness and sleep. Throughout the 1.5-hour period post-administration, oxytocin delayed REM sleep onset and reduced the proportion of both NREM and REM sleep. Conversely, IN oxytocin did not significantly alter any sleep-wake parameters at any dose tested. Caffeine demonstrated wake-promoting effects under both the IP and IN routes of administration. The involvement of OTR and V1aR binding in oxytocin-induced effects on sleep-wake outcomes will be discussed. Conclusion These findings appear to reconcile the two competing hypotheses: in rats, IP oxytocin appears to promote a state of quiescent wakefulness—one of calm and rest, but also of conscious responsivity to environmental stimuli. IN oxytocin demonstrated little to no effect on sleep-wake behaviour, which is a crucial finding given the escalating use of IN oxytocin as a therapeutic for conditions with comorbid disordered sleep. Support (if any) None.

Central Sleep Apnea Alters Neuronal Excitability and Increases the Randomness in Sleep-Wake Transitions.

While most studies on Central Sleep Apnea (CSA) have focused on breathing and metabolic disorders, the neuronal dysfunction that causes CSA remains largely unknown. Here, we investigate the underlying neuronal mechanism of CSA by studying the sleep-wake dynamics as derived from hypnograms. We analyze sleep data of seven groups of subjects: healthy adults (n=48), adults with obstructive sleep apnea (OSA) (n=29), adults with CSA (n=25), healthy children (n=40), children with OSA (n=18), children with CSA (n=73) and CSA children treated with CPAP (n=10). We calculate sleep-wake parameters based on the probability distributions of wake-bout durations and sleep-bout durations. We compare these parameters with results obtained from a neuronal model that simulates the interplay between sleep- and wake-promoting neurons. We find that sleep arousals of CSA patients show a characteristic time scale (i.e., exponential distribution) in contrast to the scale-invariant (i.e., power-law) distribution that has been reported for arousals in healthy sleep. Furthermore, we show that this change in arousal statistics is caused by triggering more arousals of similar durations, which through our model can be related to a higher excitability threshold in sleep-promoting neurons in CSA patients. We propose a neuronal mechanism to shed light on CSA pathophysiology and a method to discriminate between CSA and OSA. We show that higher neuronal excitability thresholds can lead to complex reorganization of sleep-wake dynamics. The derived sleep parameters enable a more specific evaluation of CSA severity and can be used for CSA diagnosis and monitor CSA treatment.

Evaluation of the Vibe Actigraph in Patients With Chronic Obstructive Pulmonary Disease: A Pilot Study.

Study objective: To validate the Vibe actigraph in assessing sleep-wake patterns compared to polysomnography (PSG) in patients with COPD. Methods: Nine stable COPD patients wore actigraphs while undergoing PSG. The correlation between total sleep time (TST), total sleep period (TSP), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency was determined for corresponding measurements from the actigraph and PSG. Sensitivity, specificity, and positive and negative predictive values were calculated for the actigraph, considering PSG the gold standard. Levels of agreement between the variables of PSG and the actigraph were estimated using Bland-Altman plots. Results: A strong and statistically significant correlation was noted between PSG and the actigraph in detecting movement during sleep [mean activity score (counts)], TST and TSP (all rs = 0.83; p = 0.005). The median agreement of sleep and wake counts between PSG and the actigraph was 73% and the Cohen’s Kappa value was 0.66. The medians of sensitivity and specificity of the actigraph for detecting sleep versus PSG were 84 and 66%, respectively. The median positive and negative predictive values of the actigraph were 74 and 72%, respectively. Conclusions: This study demonstrated that, under controlled laboratory conditions, the Vibe actigraph in its default settings is a promising tool for the detection of sleep-wake parameters in a small number of ambulatory patients with COPD. Clinical Impact: The actigraph used in this pilot study suggests that these devices could provide clinically relevant information in COPD to better understand the relationship between sleep and health in this population.

Linear and Nonlinear Associations between Sleep and Adjustment in Adolescence

ABSTRACT Background & Objectives A growing body of work supports linear associations between sleep and socioemotional adjustment in adolescence. However, associations between sleep and adjustment are not necessarily linear and investigations of nonlinear effects are scarce. This study examined linear and nonlinear relations between several sleep-wake parameters and externalizing behavior and internalizing symptoms in adolescence, and assessed the role of adolescent sex as a moderator of effects. Participants Participants were high school students (N = 180; M age = 17.49, SD = .62; 59% female; 68% White/European American, 32% Black/African American) from a wide range of socio-economic backgrounds living in semirural communities and small towns in Alabama. Methods Sleep-wake parameters were indexed by actigraphy-derived sleep minutes and adolescents’ reports on morningness-eveningness (circadian preference), sleep-wake problems (sleep quality), and sleepiness. Adolescents completed questionnaires on externalizing behaviors and internalizing symptoms. Results Controlling for sleep duration, a higher preference for eveningness and poor sleep quality were associated in a linear fashion with increased externalizing and internalizing symptoms. Nonlinear relations between sleepiness and internalizing symptoms emerged with pronounced sex-related effects, including somewhat delayed accelerating relations for males and rapidly accelerating associations that tended to plateau for females. Conclusions Results illustrate the importance of examining multiple sleep-wake and adjustment variables as well as linear and nonlinear associations.

Spike–Wave Discharges and Sleep–Wake States during Circadian Desynchronization: No Effects of Agomelatine upon Re-Entrainment

Rapid changes in the light–dark cycle cause circadian desynchronization between rhythms of spike–wave discharges (SWDs) and motor activity in genetic epileptic rats, and this is accompanied by an increase in epileptic activity. Given the close relationship between absence seizures and sleep–wake states, the present study assessed firstly a putative relationship between vigilance rhythms and SWDs during re-synchronization, and secondly sleep–wake patterns responsible for increased epileptic activity. Lastly, in a view of existing evidence that melatonin and its agonists accelerate re-synchronization, the effects of different doses of agomelatine upon the speed of re-synchronization of different sleep–wake states and SWDs were investigated.Simultaneous electroencephalographic and electromyographic recordings were made in symptomatic WAG/Rij rats, before, during and 10 days following an 8 h light phase delay. Agomelatine was orally administered acutely and sub-chronically, during 10 post-shift days.The magnitude of the advance after the shift and the speed of re-synchronization were specific for various rhythms. Most prominent change was the increase in REM sleep duration during the dark phase. A post-shift increase in passive wakefulness and a reduction in deep slow-wave sleep coincided with an aggravation of SWDs during the light phase. Agomelatine showed neither an effect on sleep–wake parameters and SWDs, nor affected re-synchronization.The same speed of re-synchronization of SWDs and light slow-wave sleep suggests that both are controlled by a common circadian mechanism. The redistribution of SWDs and their increase in the light phase after the shift may be of importance for patients with absence epilepsy planning long trans-meridian flight across time zones.

Misaligned core body temperature rhythms impact cognitive performance of hospital shift work nurses.

Circadian rhythms greatly influence 24-h variation in cognition in nearly all organisms, including humans. Circadian clock impairment and sleep disruption are detrimental to hippocampus-dependent memory and negatively influence the acquisition and recall of learned behaviors. The circadian clock can become out of sync with the environment during circadian misalignment. Shift work represents a real-world model of circadian misalignment that can be studied for its physiological implications. The present study aimed to test the hypothesis that circadian misalignment disrupts vigilance and cognitive performance on occupationally relevant tasks using shift work as a model. As such, we sought to (1) explore the general effects of night- and day-shift worker schedules on sleep-wake parameters and core body temperature (CBT) phase, and (2) determine whether shift-type and CBT phase impact cognitive performance and vigilance at the end of a 12-h shift. We observed a sample of day-shift and night-shift hospital nurses over a 10-day period. At the end of three, consecutive, 12-h shifts (7 pm-7am or 7am-7 pm), participants completed a cognitive battery assessing vigilance, cognitive throughput, and medication calculation fluency (via an investigator developed and tested metric). Night-shift nurses exhibited significantly greater sleep fragmentation as well as a greater disparity between their wake-time and time of CBT minimum compared to day-shift nurses. Night-shift nurses exhibited significantly slower cognitive proficiency at the end of their shifts, even after adjustment for CBT phase. These results suggest that circadian disruption and reduced sleep quality both contribute to cognitive functioning and performance.

Depression-like behaviors induced by chronic corticosterone exposure via drinking water: Time-course analysis

Hypothalamic-pituitary-adrenal (HPA) axis activity is commonly dysregulated in stress-related psychiatric disorders. The corticosterone rat model was developed to understand the influence of stress on depression-like symptomatology. To further understand the effects of corticosterone on the development of depression-like behavior, rats were continuously exposed to corticosterone (200 μg/ml) or vehicle via drinking water daily for 21 days. The rats underwent a series of behavioral tests, and electroencephalographical recordings were performed after 7, 14, and 21 days of treatment. The measurements included immobility time (i.e., despair) in the forced swim test, locomotor activity in the open field test, sucrose consumption (i.e., anhedonia) in the sucrose preference test, and sleep-wake parameters. The rats in the 7-day corticosterone exposure group exhibited depression-like behavior, including increases in despair, anhedonia, anxiety, and sleep impairments. The rats in the 14-day corticosterone exposure group exhibited normal patterns of behavior and sleep structure. When corticosterone exposure was extended to 21 days, depression-like symptoms recurred, including despair, anhedonia, anxiety, and sleep disturbances. Overall, the present study observed U-shaped depression-like effects across 3 weeks of corticosterone exposure via drinking water.

P 120 A machine learning approach to detecting sleep and sleep disorders in acceleration sensor data

The major diagnostic sleep laboratory tool for assessing excessive daytime sleepiness (EDS), the multiple sleep latency test (MSLT), is increasingly criticized for poor precision in the differentiation of idiopathic hypersomnia (IH) and narcolepsy ( Trotti et al., 2013 , Johns, 2000 ). Recent evidence suggests that actigraphy can supplement the diagnostic process by providing information about the sleep-wake rhythm ( Kretzschmar et al., 2016 , Filardi et al., 2015 , Bruck et al., 2005 ). An actigraphy analysis tool is introduced that processes actigraphy recordings with machine learning methods. It is preliminarily validated for recordings of hypersomnolent patients. Sleep is detected using a support vector machine (SVM) with 61 features describing the actigraphy signal. Testing the prediction against polysomnographically validated labels on nocturnal recordings of hypersomnolent patients showed an accuracy of 87%, a sensitivity of 93% and a specificity of 51%. Post-processing the prediction with morphological operations increases the specificity to 73%, with only minor declines in accuracy and sensitivity (85% and 88%, respectively). Individually training an SVM per patient revealed the most promising results with 95% accuracy, 73% specificity and 99% sensitivity. Each detected sleep phase is automatically verified in order to not be confused with episodes of unattached actigraphy device. Moreover, an SVM is trained to identify the main sleep episode of each day, based on features describing a sleep phase’s probability of being a nap. Testing with manually generated labels of 14-day actigraphies of EDS patients showed that 90% of the sleep phases receive the correct label (diurnal or nocturnal sleep), with a specificity of 96% and a sensitivity of 86%. Finally, the classifiers’ annotations are used to calculate 217 sleep-wake rhythm and motor activity parameters. Comparing the automatically derived sleep-wake parameters of 15 long-term actigraphies from IH patients to previously published results ( Filardi et al., 2015 ) showed good accordance. Altogether, the developed tool and the methods used appear a promising pathway for future investigations in the search for disorder inherent sleep-wake rhythm and motor activity patterns in big patient cohorts.

Octacosanol restores stress-affected sleep in mice by alleviating stress

Octacosanol, a component of various food materials, possesses prominent biological activities and functions. It fights against cellular stress by increasing glutathione level and thus scavenging oxygen reactive species. However, its anti-stress activity and role in sleep induction remained elusive. We hypothesize that octacosanol can restore stress-affected sleep by mitigating stress. Cage change strategy was used to induce mild stress and sleep disturbance in mice, and effects of octacosanol administration on amount of sleep and stress were investigated. Results showed that octacosanol did not change rapid eye movement (REM) or non-REM (NREM) sleep compared to vehicle in normal mice. However, in cage change experiment, octacosanol induces significant increase in NREM sleep at doses of 100 and 200 mg/kg (75.7 ± 14.9 and 82.7 ± 9.3 min/5 h) compared to vehicle (21.2 ± 5.1 min/5 h), and decreased sleep latency. Octacosanol induced sleep by increasing number of sleep episodes and decreasing wake episode duration. Plasma corticosterone levels were significantly reduced after octacosanol (200 mg/kg) administration, suggesting a decrease in stress level. Octacosanol-induced changes in sleep-wake parameters in stressed-mice were comparable to the values in normal mice. Together, these data clearly showed that, though octacosanol does not alter normal sleep, it clearly alleviates stress and restore stress-affected sleep.