Ratings Of Sleepiness Research Articles

Acceptability and Impact of Office-Based Resistance Exercise Breaks.

Breaking up sedentary behavior with standing or walking can decrease discomfort, fatigue, and sleepiness. However, less is known about acceptability and impact of resistance exercise breaks on these outcomes. Therefore, we evaluated the acceptability of resistance exercise breaks and their influence on discomfort, physical and mental fatigue, and sleepiness during occupational sitting. Workers completed two 4-hour conditions in random order: prolonged sitting (SIT) and sitting with hourly resistance exercise breaks (REX). All outcomes were measured at baseline and every hour thereafter with five total breaks. Linear mixed models evaluated overall condition effects and differences at each hour. Cohen's d estimated magnitudes of effect. Acceptability was assessed via questionnaire after the REX condition and reported as percentages. Fourteen adults (age: 53.4 ± 9.5 years, body mass index [BMI]: 30.9 ± 4.8 kg/m2) were enrolled. Although ratings of discomfort, fatigue, and sleepiness were typically lower during REX as compared with SIT, overall outcomes were not significantly different between conditions (p > .05). However, a significant reduction in mental fatigue at hour 4 in favor of the REX condition (β = -0.48 log-points, p < .05, d = 0.37) was observed. Program acceptability questions revealed the majority (>50%) of participants reported a "4" or "5" on a 5-point Likert-type scale for all questions, indicating high acceptability for implementation. Resistance exercise breaks had high acceptability and provided preliminary evidence of improving ratings of mental fatigue. More research is needed to better understand the role of resistance training to reduce sedentary behavior.

Feasibility and acute alerting effects of a daylight-supplementing in-vehicle lighting system – Results from two randomised controlled field studies during dawn and dusk

The present studies examined the feasibility and acute alerting effects of additional in-vehicle lighting within a passenger car. These factors were examined during morning driving (Study 1) and evening driving (Study 2). In a balanced within-subjects design, 37 participants drove a test car two times in the morning or in the evening. The test vehicle was equipped with either a daylight-supplementing interior lighting system or a placebo system, which participants were told would refresh the air. Both studies used identical protocols, and participants participated either in Study 1 ( n = 18) or Study 2 ( n = 19). In both studies, corneal illuminance levels were recorded while driving. Feasibility of the systems was assessed using subjective ratings. Efficacy outcomes were spindle rates in the alpha bandwidth of electroencephalogram recordings, performance on a psychomotor vigilance task and subjective sleepiness ratings. In both studies, daylight-supplementing significantly increased corneal illuminances while driving and did not cause any negative visual side-effects. Study 1 revealed lower spindle rates while driving under daylight-supplementing lighting, indicating that drivers had higher physiological alertness when exposed to additional light in the morning. This alerting effect of daylight-supplementing lighting, however, was not observed in Study 2. In both studies, performance on the psychomotor vigilance task as well as subjective sleepiness ratings did not significantly differ between the experimental conditions. The present studies provide novel evidence for the feasibility and positive impact of daylight-supplementing in-vehicle lighting systems on the physiological alertness of drivers under naturalistic driving conditions. Further studies are warranted to evaluate carry-over effects of increased alertness on road safety measures.

The effect of a daytime 60-min nap opportunity on postural control in highly active individuals.

Although napping is commonly used as a strategy to improve numerous physical and cognitive performances, the efficacy of this strategy for improving postural balance has not yet been elucidated. Thus, the aim of this study was to conduct a comprehensive examination of the effect of a 60 min nap opportunity (N60) on different components of postural control. Ten highly active individuals (age = 27 ± 3.5 y, height = 1.75 ± 0.52 m, weight = 66.02 ± 8.63 kg) performed, in a randomized order, two afternoon test sessions following no nap (NN) and N60. Postural balance was assessed using the sensory organisation test (SOT), the unilateral stance test (UST), and the limits of Stability Test performed on NeuroCom® Smart Balance Master. The subjective rating of sleepiness before and after the nap conditions was also assessed. Compared to NN, N60 improved the composite balance score (p < 0.05, ES = 0.75, Δ = 5.3%) and the average and maximum percentage balance in the most challenging postural conditions of the SOT (p < 0.05 for SOT-4 and 5 and p < 0.0005 for SOT-6; ES range between 0.58 and 1.1). This enhanced postural balance in N60 was accompanied with improved visual (p < 0.05; ES = 0.93; Δ = 8.9%) and vestibular (p < 0.05; ES = 0.81; Δ = 10.5%) ratios and a reduced level of sleepiness perception (p < 0.001, ES = 0.87). However, no significant differences were found in any of the UST and LOS components’ scores (p > 0.05). Overall, a 60 min post lunch nap opportunity may be viable for improving static balance, although further work, involving larger samples and more complex motor activities, is warranted.

Unethical Decision Making and Sleep Restriction: Experimental Evidence

Recent examinations into the cognitive underpinnings of ethical decision making has focused on understanding whether honesty is more likely to result from deliberative or unconscious decision processes. We randomly assigned participants to a multi-night sleep manipulation, after which they completed 3 tasks of interest: imperfectly identifiable dishonesty (the Coin Flip task), identifiable dishonesty (the Matrix task), and anti-social allocation choices (the Money Burning game). We document the validity of the sleep protocol via significantly reduced nightly sleep levels (objectively measured using validated instrumentation) and significantly higher sleepiness ratings in the sleep-restricted (SR) group compared to the wellrested (WR) group. We report that money burning decisions are not statistically different between SR and WR participants. However, regarding honesty, we find significant and robust effects of SR on honesty. In total, given the connection between sleepiness and deliberation, these results add to the literature that has identified conditions under which deliberation impacts ethical choice. When dishonesty harms an abstract “other” person (e.g., the researcher’s budget), reduced deliberation more likely increases dishonesty compared to when harm is done to someone at closer social distance (e.g., another subject). Key Words: Ethical choice, dishonesty, antisocial behavior, sleep.

The impact of dayshifts and sleepover nightshifts on the eating and driving behaviours of residential support workers: An exploratory workplace study

Residential support workers (RSWs) provide 24-hour care to clients and many work overnight sleepover nightshifts. Although RSWs perform safety-critical tasks and are at high-risk of work stress and exhaustion, the health and safety of RSWs has not been investigated. This explorative workplace case study explored the impact of support work on the eating and driving behaviours of RSWs. Thirteen RSWs who had worked a dayshift (n = 6) or a sleepover nightshift (n = 7) completed questions on the timing of food intake during their shift, motivations for eating during the shift, subjective work performance, alertness and sleepiness post-shift, and driving performance post-shift. RSWs reported snacking during the night on a sleepover nightshift. Time available was the biggest determinant for when RSWs ate during a day and sleepover nightshift. Ratings of subjective alertness and sleepiness after eating were not different between shift types, however participants reported an increase in work performance after eating during a dayshift. Driving events were more frequently reported post-sleepover nightshift, compared to post-dayshift. Findings demonstrate an impact of shift type on eating and driving behaviours of RSWs and highlight the importance of further investigation of this under-researched group to identify appropriate strategies for improving health and safety.

Circadian tau differences and rhythm associations in delayed sleep-wake phase disorder and sighted non-24-hour sleep-wake rhythm disorder.

We investigated biological and behavioral rhythm period lengths (i.e. taus) of delayed sleep-wake phase disorder (DSWPD) and non-24-hour sleep-wake rhythm disorder (N24SWD). Based on circadian phase timing (temperature and dim light melatonin onset), DSWPD participants were dichotomized into a circadian-delayed and a circadian non-delayed group to investigate etiological differences. Participants with DSWPD (n = 26, 17 m, age: 21.85 ± 4.97 years), full-sighted N24SWD (n = 4, 3 m, age: 25.75 ± 4.99 years) and 18 controls (10 m, age: 23.72 ± 5.10 years) participated in an 80-h modified constant routine. An ultradian protocol of 1-h "days" in dim light, controlled conditions alternated 20-min sleep/dark periods with 40-min enforced wakefulness/light. Subjective sleepiness ratings were recorded prior to every sleep/dark opportunity and median reaction time (vigilance) was measured hourly. Obtained sleep (sleep propensity) was derived from 20-min sleep/dark opportunities to quantify hourly objective sleepiness. Hourly core body temperature was recorded, and salivary melatonin assayed to measure endogenous circadian rhythms. Rhythm data were curved using the two-component cosine model. Patients with DSWPD and N24SWD had significantly longer melatonin and temperature taus compared to controls. Circadian non-delayed DSWPD had normally timed temperature and melatonin rhythms but were typically sleeping at relatively late circadian phases compared to those with circadian-delayed DSWPD. People with DSWPD and N24SWD exhibit significantly longer biological circadian rhythm period lengths compared to controls. Approximately half of those diagnosed with DSWPD do not have abnormally delayed circadian rhythm timings suggesting abnormal phase relationship between biological rhythms and behavioral sleep period or potentially conditioned sleep-onset insomnia.

Frequency-Dependent Light Stimulation Effects on Performance During Vigilance Tasks on a Laptop.

Students, office workers, or other computer and mobile device users can suffer from decrements in alertness or productivity, but many intervention methods on these can be too distracting or even affect daily routines. Using heart rate (HR) to determine a fast and slow target frequency at which to oscillate light brightness stimulation on a laptop, thirty-six participants joined a cognitive task where we hypothesized that fast frequency stimulation would increase alertness and decrease relaxation, while slow frequency stimulation would have the opposite effects. We found that slow frequency stimulation produces a statistically significant delay in response time, users react more slowly (3.8e2 ± 5.5e1 ms), when compared to the no stimulation (3.7e2 ± 4.1e1 ms) (p = 9.0e-3) conditions. The (Slow - No Stimulation) response time (1.7e1 ± 2.7e2 ms) produced a statistically significant delay in response time versus the (Fast - No Stimulation) response time (-0.74 ± 2.4e1 ms) (p = .016). These delays due to slow stimulation occurred without influencing accuracy or subjective sleepiness ratings. We observed that frequency-dependent light stimulation can potentially influence HRV metrics such as the mean normal-to-normal intervals and mean HR. Future work will target breathing rate to determine light stimulation oscillations as we further investigate the potential of using the slow-frequency domain to unobtrusively influence user performance and physiology.

Cardiovascular and somatic comorbidities and sleep measures using three hypopnea criteria in mild obstructive sleep-disordered breathing: sex, age, and body mass index differences in a retrospective sleep clinic cohort.

To describe sex, age, and body mass index (BMI) differences in comorbidities and polysomnography measures, categorized using 3 different apnea-hypopnea index (AHI) criteria in sleep clinic patients with mild obstructive sleep-disordered breathing. A retrospective cohort of 305 (64% female) adult sleep clinic patients who underwent full-night in-laboratory polysomnography having been diagnosed with mild sleep-disordered breathing and prescribed positive airway pressure. Effects of sex, age, and BMI on comorbidities and polysomnography measures, including rates of AHI defined by ≥ 3% desaturations (AHI3%), with arousals (AHI3%A), by ≥ 4% desaturations (AHI4%), and by respiratory disturbance index, were evaluated. Sixty-nine (23%), 116 (38%), 258 (85%), and 267 (88%) patients had AHI4%, AHI3%, AHI3%A, and respiratory disturbance index ≥ 5 events/h, respectively. Ninety-day positive airway pressure adherence rates were 45.9% overall and higher in women > 50-years-old (51.2%, P = 0.013) and men (54.5%, P = 0.024) with no difference whether AHI4% or AHI3%A was < 5 or ≥ 5 events/h. Men and women had similar rates of daytime sleepiness (43.3%), anxiety (44.9%), and hypertension (44.9%). Women were more likely to have obesity, anemia, asthma, depression, diabetes, fibromyalgia, hypothyroidism, migraine, and lower rates of coronary artery disease. More patients with AHI4% < 5 events/h had depression, migraines, and anemia, and more patients with AHI4% ≥ 5 events/h had congestive heart failure. Women were more likely to have higher sleep maintenance and efficiency, shorter average obstructive apnea and hypopnea durations, and less supine-dominant pattern. Average obstructive apnea and hypopnea duration decreased with increasing BMI, and average hypopnea duration increased with age. Obstructive apnea duration and obstructive hypopnea with arousal duration decreased with increasing BMI. More women had AHI4% < 5 (81.5% vs 69.1%), AHI3% < 5 (68.7% vs 49.1%), and AHI3%A < 5 events/h (18.5% vs 10.0%). Greater age and higher BMI were associated with higher AHI. Current AHI criteria do not predict comorbidities or adherence in mild sleep-disordered breathing patients. In this hypothesis-generating descriptive analysis, sex, BMI, and age may all be factors that should be accounted for in future research of mild sleep-disordered breathing patients. Different sleep study measures may weigh differently in calculations of risk for cardiovascular versus somatic comorbidities.

The experience of sleep deprivation for midwives practicing in the united states

Midwives in the United States who work shifts longer than 12h have higher rates of excessive daytime sleepiness than midwives who work shifts of 12h or less. Increased levels of excessive daytime sleepiness can lead to negative life impacts and may increase the risk for accidents and professional burnout. To describe midwives' experiences related to sleep and sleep deprivation as a result of their work and call-shift schedules. A survey designed to explore the experience and impact of work on sleep and sleepiness among midwives in the United States was sent to members of the American College of Nurse-Midwives (N=4358). The survey included an open-ended question about midwives' experiences related to sleep or sleep deprivation. This analysis of the qualitative data was conducted using qualitative description and qualitative content analysis by two of the authors. There were a total of 753 midwife respondents (response rate=17%); of those 268 responded to the qualitative question about sleep. Three main themes were identified: barriers and challenges contributing to sleep deprivation; negative consequences of sleep deprivation; and strategies that helped midwives cope with or reduce sleep deprivation. Midwives reported suffering health and safety consequences as a result of insufficient sleep, including impacts to their personal health, clinical errors, and errors in driving after an extended period awake. Nurses, midwives, physicians, and administrators are encouraged to work together to develop strategies and policies to ameliorate the risks and impacts of sleep deprivation for all clinicians, including midwives.

1101 Daytime Interactions Of Anxiousness, Stressfulness, Sleepiness, And Fatigue In College Students: A Longitudinal Cluster Analysis

Abstract Introduction Reports of anxiety and stress are increasing among college-age students. Previous findings show bi-directional relationships with nighttime sleep loss and elevated anxiety and stress. Less is known about changes across the day (profiles) in anxiousness and stress, and their relationship to daytime sleepiness and fatigue profiles. The primary objective of this study was to examine these potential interactions. Methods Using an ecological momentary assessment design, university undergraduates (N=102, female= 77.5%) made smart phone ratings (0-9 Scale) of anxiousness, stressfulness, fatigue, sleepiness from Monday-Friday, six times per day. Participant were either Low-Anxious (0-1 score: n=34) or High-Anxious (&amp;gt;7 score; n=68) on the GAD-Q-IV Scale, had &amp;gt; 7h sleep per weeknight, and bed- and wake times between 06:30-09:30 and 22:30-02:00, respectively. Mean daytime profile interactions were examined using joint-trajectory longitudinal clustering. Results Clustering identified two subtypes, Lo (n=46) and Hi (n=56), which differed primarily in their quadratic curve levels, and in times of highest and lowest ratings. Subtypes differed (p&amp;lt;.001) in overall mean ratings of anxiousness (Lo=1.6±0.9, Hi=3.6±1.1), stressfulness (Lo=2.0±0.9, Hi=4.3±1.1), fatigue (Lo=2.4±1.0, Hi=4.4±1.0), and sleepiness (Lo=2.9±1.0, Hi=4.3±1.1). Subtypes were similar in age (Lo=18.6±0.9, Hi=18.9±1.3), morningness-eveningness BALM (Lo=33.2±4.1, Hi=32.1±5.1) and MEQ (Lo=47.5±6.2, Hi=47.7±6.8) scores, and hours sleep (Lo=8.5±0.8, Hi=8.4±0.9). Notably, more females were Hi subtype (83.9%) than Lo subtype (69.6%). Also, GAD-Q-IV scores differed within subtypes: Hi (80.4% High-Anxiety, 19.6% Low-Anxiety) versus Lo (50.0% for both High- and Low-Anxiety). Conclusion Despite apparent adequate nightly sleep, elevated anxiousness and stressfulness may be accompanied by increased daytime fatigue and sleepiness in college students. Furthermore, standardized clinical tests designed to identify levels of anxiety and stress may not align with daily experiences of those states. Better understanding of concomitant daytime profiles of anxiousness, stress, sleepiness, and fatigue could facilitate treatment development and reduce the burden on student counseling centers. Support None

0297 Relationship Between Sleepiness Symptoms Questionnaire Ratings and Psychomotor Vigilance Performance in a Total Sleep Deprivation Study

Abstract Introduction While measuring the neurobehavioral consequences of sleepiness is arguably best done with performance tasks providing objective assessments of impairment, this often proves challenging in real-world operational settings. Self-report instruments measuring subjective sleepiness provide a practical alternative, but field studies generally fail to show high correlation between objective and subjective assessments of impairment. The Sleepiness Symptoms Questionnaire (SSQ) is a self-report instrument developed to address this issue by asking about observable symptoms of sleepiness and (motor vehicle driving) performance impairment. In a laboratory sleep deprivation study, we compared SSQ sleepiness ratings to performance impairment on a 10min psychomotor vigilance test (PVT). Methods N=12 healthy normal sleepers (ages 21-39y, 6 females) participated in a 4-day in-laboratory study. After a baseline day (9h time in bed; 22:00-07:00), subjects underwent 38h total sleep deprivation (TSD) followed by a recovery day (9h time in bed; 22:00-07:00). As part of neurobehavioral testing throughout the experiment, subjects completed the SSQ and PVT back to back at 6.5h, 14.5h, 22.5h, and 30.5h TSD, and 6.5h after recovery sleep. Data from one subject were incomplete and discarded prior to analysis. Results As TSD progressed, the SSQ sleepiness ratings and the number of lapses (RTs&amp;gt;500ms) on the PVT were elevated, with sleepiness and performance impairment peaking at 22.5h TSD. Both measures returned to baseline levels after recovery sleep. Mixed-effects analysis of covariance showed moderate correlation between SSQ ratings and PVT lapses (r=0.44, F1,43=24.1, p&amp;lt;0.001). Conclusion Self-reported sleepiness on the SSQ reflected the expected homeostatic and circadian changes in sleep pressure during TSD and following recovery sleep, as did PVT performance impairment. The moderate correlation between subjective ratings on the SSQ, with its emphasis on observable sleepiness symptoms, and objective impairment on the PVT suggests that the SSQ may be a reasonably reliable instrument for measuring sleepiness under conditions of acute sleep deprivation. Support Jazz Pharmaceuticals

Sleepiness on the flight deck: Reported rates of occurrence and predicted fatigue risk exposure associated with UK airline pilot work schedules

Abstract Survey and field studies conducted with commercial airline pilots suggest that in-flight sleepiness and related involuntary sleep phenomena are experienced by pilots during their duties. However, for methodological, practical and commercial reasons, there is a lack of publicly available research data of per-flight hour rates of sleepiness experienced by pilots or predicted fatigue risk rates associated with pilots’ hours of work. This empirical field study sought to address this gap by collecting self-reported sleepiness/alertness ratings from pilots from 18 different UK airlines via a mobile phone app over the period of August 2017. In tandem, predicted sleepiness levels and sleep opportunities associated with participants’ flown rosters were investigated using biomathematical fatigue modelling. Findings indicated that a quarter of all flying duty periods were predicted to be preceded by a main sleep opportunity shorter than six hours, whilst 10% of all flying hours were associated with elevated fatigue risk levels. Pilots reported 7.3 reports of involuntary sleep on the flight deck per 1000 flying hours, which represents a rate far greater than that previously reported to the regulator. By comparison, the rates of predicted and recorded fatigue-related incapacitations greatly exceeded the target rate of medical incapacitation permissible under the medical incapacitation safety standard for commercial aviation of less than one occurrence per 1,000,000 h.

Manipulating sleep duration perception changes cognitive performance – An exploratory analysis

To test the effect of perceived sleep duration on cognitive performance. Sixteen healthy individuals [8F; mean age (± SD): 24.2±3.0years)] received an 8-h sleep opportunity followed by a 5-h opportunity on two consecutive nights. Upon waking, they were randomized to being informed that they received either an 8-h or 5-h sleep opportunity, via a clock that ran either fast, slow or normally. Cognitive performance was assessed using 10-min auditory psychomotor vigilance tests and subjective sleepiness ratings. Homeostatic and circadian sleep drive was assessed using waking electroencephalography (EEG). Reaction time was significantly quicker when individuals thought that they had slept for 8h but given a 5-h sleep opportunity. Conversely, reaction times were significantly slower when individuals thought they had 5h of sleep but given an 8-h sleep opportunity. EEG delta power (1.0-4.5Hz) during wake increased significantly when sleep was restricted to 5h, and individuals thought they slept for 5h, but this increase was attenuated with a perceived sleep duration of 8h following a 5-h opportunity. EEG delta power did not increase, however, with perceived sleep restriction. EEG high-alpha activity (10.5-11.5Hz) was consistently higher when participants thought that they had an 8-h sleep opportunity, regardless of the actual duration. These results suggest that perceived sleep duration may modulate psychosomatic responses. Additional studies with predefined outcomes and analyses are necessary to confirm these findings, which may have important implications for understanding how sleep affects cognition and psychosomatic responses.

Are long-haul truck drivers unusually alert? A comparison with long-haul airline pilots

Recent studies suggest heavy vehicle drivers self-estimate their sleepiness unexpectedly low during night duties. The present study compared sleepiness ratings of long-haul truck drivers with those of long-haul airline pilots during night and non-night duties. In addition, the correspondence between self-rated manifest and predicted latent sleepiness was examined in the two groups. Twenty-two drivers and 33 pilots participated. Their working hours, sleep, on-duty sleepiness, and use of sleepiness countermeasures were measured in naturalistic conditions. Predictions of latent sleepiness were based on the measurements of working hours and sleep using the Sleep/Wake Predictor modelling tool. Drivers rated lower levels of sleepiness than pilots during both duty types, though predicted latent sleepiness levels were very similar among the two groups. Neither the results of sleep nor those of sleepiness countermeasures explained the difference in self-rated sleepiness. The results raise the possibility that long-haul truck drivers are actually sleepier than they report, and thus are at an increased risk for not responding to sleepiness in a timely manner. A potential explanation for this behavior is lack of education and training on sleepiness among truck drivers as compared with airline pilots. Alternatively, long-haul truck drivers may be exceptionally tolerant to soporific working conditions. The first reported results do not, however, support this hypothesis.

Daytime Exposure to Blue-Enriched Light Counters the Effects of Sleep Restriction on Cortisol, Testosterone, Alpha-Amylase and Executive Processes.

Sleep debt is becoming a better acknowledged cause of physiological stress and neurobehavioral deficits with major public-health concerns. We investigated whether exposure to blue light during daytime could be an efficient countermeasure to limit sleep restriction’s impact on relevant behavioral (stress, sleepiness, sustained attention, and memory performance) and physiological (saliva cortisol, testosterone, and alpha-amylase) markers. Our semi-ecological, crossover, randomized design included 17 young men that underwent two sleep-restricted nights (3 h each) followed or not by blue light exposure (30-min-long sessions at 100 lux repeated four times throughout the day). Behavioral and physiological measurements were performed in the lab but outside these periods the participants kept following their usual routine. After sleep restriction, morning cortisol and testosterone, and afternoon alpha-amylase levels decreased. In parallel, subjective ratings of stress and sleepiness increased while performance on the sustained attention and memory tasks deteriorated. In contrast, after periods of blue light exposure, all these parameters were largely restored to baseline levels, despite an identical sleep restriction procedure, although this restorative effect was reduced for the memory task. Our findings suggest that even short exposure to blue light could trigger persistent beneficial effects throughout the day and could be potentially efficient in real-life settings.

Counteracting effect of verbal ratings of sleepiness on dual task interference.

The aim of the present study was to demonstrate the effect of verbal ratings on arousal in the electroencephalogram (EEG) and psychomotor vigilance test (PVT) performance. Thirty participants underwent the PVT for 40 min in three experimental conditions: (1) Rating condition, in which they verbally rated subjective sleepiness with Karolinska sleepiness scale, following pure tone sound played every 20 s during PVT, (2) No-rating condition, in which they underwent PVT with the similar sound as the Rating experiment but without the verbal rating task, and (3) Control condition, in which they underwent PVT with a no-sound stimulus and without the verbal rating task. The results show that during the first half of the task epoch, alpha power density was lower in the Rating than in the No-rating condition, while performance was not different between the conditions. During the second half of the task epoch, performance was better in the Non-rating than in the Rating condition, but no difference in the alpha power density. These results suggest that performance deterioration could be masked by the arousal effect of the dual task itself. It could also explain why the PVT performance and arousal in EEG sometimes dissociate, particularly in dual task situations.

Evidence That Homeostatic Sleep Regulation Depends on Ambient Lighting Conditions during Wakefulness.

We examined whether ambient lighting conditions during extended wakefulness modulate the homeostatic response to sleep loss as indexed by. slow wave sleep (SWS) and electroencephalographic (EEG) slow-wave activity (SWA) in healthy young and older volunteers. Thirty-eight young and older participants underwent 40 hours of extended wakefulness [i.e., sleep deprivation (SD)] once under dim light (DL: 8 lux, 2800 K), and once under either white light (WL: 250 lux, 2800 K) or blue-enriched white light (BL: 250 lux, 9000 K) exposure. Subjective sleepiness was assessed hourly and polysomnography was quantified during the baseline night prior to the 40-h SD and during the subsequent recovery night. Both the young and older participants responded with a higher homeostatic sleep response to 40-h SD after WL and BL than after DL. This was indexed by a significantly faster intra-night accumulation of SWS and a significantly higher response in relative EEG SWA during the recovery night after WL and BL than after DL for both age groups. No significant differences were observed between the WL and BL condition for these two particular SWS and SWA measures. Subjective sleepiness ratings during the 40-h SD were significantly reduced under both WL and BL compared to DL, but were not significantly associated with markers of sleep homeostasis in both age groups. Our data indicate that not only the duration of prior wakefulness, but also the experienced illuminance during wakefulness affects homeostatic sleep regulation in humans. Thus, working extended hours under low illuminance may negatively impact subsequent sleep intensity in humans.

Sleep in children with Smith-Magenis syndrome: a case-control actigraphy study.

The objectives of the study were (1) to compare both actigraphy and questionnaire-assessed sleep quality and timing in children with Smith-Magenis syndrome (SMS) to a chronologically age-matched typically developing (TD) group and (2) to explore associations between age, nocturnal and diurnal sleep quality, and daytime behavior. Seven nights of actigraphy data were collected from 20 children with SMS (mean age 8.70; SD 2.70) and 20 TD children. Daily parent/teacher ratings of behavior and sleepiness were obtained. Mixed linear modeling was used to explore associations between total sleep time and daytime naps and behavior. Sleep in children with SMS was characterized by shorter total sleep time (TST), extended night waking, shorter sleep onset, more daytime naps, and earlier morning waking compared to the TD group. Considerable inter-daily and inter-individual variability in sleep quality was found in the SMS group, so caution in generalizing results is required. An expected inverse association between age and TST was found in the TD group, but no significant association was found for the SMS group. No between-group differences in sleep hygiene practices were identified. A bidirectional negative association between TST and nap duration was found for the SMS group. In the SMS group, increased afternoon sleepiness was associated with increased irritability (p = .007) and overactivity (p = .005). These findings evidence poor sleep quality in SMS and the need to implement evidence-based interventions in this population.

Natural history of excessive daytime sleepiness: a population-based 5-year longitudinal study.

To document the rates of persistent, remitted, and intermittent excessive daytime sleepiness (EDS) in a longitudinal 5-year community study of adults and to assess how changes in risk factors over time can predict improvement of daytime sleepiness (DS). Participants were recruited in 2007-2008 as part of a population-based epidemiological study implemented in Canada. They completed postal assessments at baseline and at each yearly follow-up. An Epworth Sleepiness Scale total score >10 indicated clinically significant EDS; a 4-point reduction between two consecutive evaluations defined DS improvement. Socio-demographic, lifestyle, health characteristics, and sleep-related measures (e.g. insomnia symptoms, sleep duration, sleep medication) were self-reported at each time point. Cox proportional-hazard models were used to predict EDS and DS remissions over 5 years. Among the 2167 participants, 33% (n = 714) met criteria for EDS at baseline, of whom 33% had persistent EDS, 44% intermittent EDS, and 23% remitted EDS over the follow-up. Furthermore, 61.4% of 2167 initial participants had stable DS, 27.1% sustained DS improvement and 8.5% transient improvement over the follow-up. The main predictors of EDS remission or DS improvement were normal weight, taking less hypnotics, having hypertension, increased nighttime sleep duration, and decreased insomnia, and depressive symptoms. EDS waxes and wanes over time with frequent periods of remission and is influenced by behavioral characteristics and changes in psychological, metabolic, and nighttime sleep patterns. Targeting these predictors in future interventions is crucial to reduce DS in the general adult population.

Effect of Light Flashes vs Sham Therapy During Sleep With Adjunct Cognitive Behavioral Therapy on Sleep Quality Among Adolescents

Owing to biological, behavioral, and societal factors, sleep duration in teenagers is often severely truncated, leading to pervasive sleep deprivation. To determine whether a novel intervention, using both light exposure during sleep and cognitive behavioral therapy (CBT), would increase total sleep time in teenagers by enabling them to go to sleep earlier than usual. This double-blind, placebo-controlled, randomized clinical trial, conducted between November 1, 2013, and May 31, 2016, among 102 adolescents enrolled full-time in grades 9 to 12, who expressed difficulty going to bed earlier and waking up early enough, was composed of 2 phases. In phase 1, participants were assigned to receive either 3 weeks of light or sham therapy and were asked to try to go to sleep earlier. In phase 2, participants received 4 brief CBT sessions in addition to a modified light or sham therapy. All analyses were performed on an intent-to-treat basis. Light therapy consisted of receiving a 3-millisecond light flash every 20 seconds during the final 3 hours of sleep (phase 1) or final 2 hours of sleep (phase 2). Sham therapy used an identical device, but delivered 1 minute of light pulses (appearing in 20-second intervals, for a total of 3 pulses) per hour during the final 3 hours of sleep (phase 1) or 2 hours of sleep (phase 2). Light therapy occurred every night during the 4-week intervention. Cognitive behavioral therapy consisted of four 50-minute in-person sessions once per week. Primary outcome measures included diary-based sleep times, momentary ratings of evening sleepiness, and subjective measures of sleepiness and sleep quality. Among the 102 participants (54 female [52.9%]; mean [SD] age, 15.6 [1.1] years), 72 were enrolled in phase 1 and 30 were enrolled in phase 2. Mixed-effects models revealed that light therapy alone was inadequate in changing the timing of sleep. However, compared with sham therapy plus CBT alone, light therapy plus CBT significantly moved sleep onset a mean (SD) of 50.1 (27.5) minutes earlier and increased nightly total sleep time by a mean (SD) of 43.3 (35.0) minutes. Light therapy plus CBT also resulted in a 7-fold greater increase in bedtime compliance than that observed among participants receiving sham plus CBT (mean [SD], 2.21 [3.91] vs 0.29 [0.76]), as well as a mean 0.55-point increase in subjective evening sleepiness as compared with a mean 0.48-point decrease in participants receiving sham plus CBT as measured on a 7-point sleepiness scale. This study found that light exposure during sleep, in combination with a brief, motivation-focused CBT intervention, was able to consistently move bedtimes earlier and increase total sleep time in teenagers. This type of passive light intervention in teenagers may lead to novel therapeutic applications. ClinicalTrials.gov identifier: NCT01406691.