24 hours of sleep deprivation in the rat increases sleepiness and decreases vigilance: introduction of the rat‐psychomotor vigilance task

A novel animal‐analog of the human psychomotor vigilance task (PVT) was validated by subjecting rats to 24 h of sleep deprivation (SD) and examining the effect on performance in the rat‐PVT (rPVT), and a rat multiple sleep latency test (rMSLT). During a three‐phase (separate cohorts) crossover design, vigilance performance in the rPVT was compared with 24 h SD‐induced changes in sleepiness assessed by polysomnographic evaluation and the rMSLT. Twenty‐four hours of SD was produced by brief rotation of activity wheels at regular intervals in which the animals resided throughout the experiment. In the rPVT experiment, exercise controls (EC) experienced the same overall amount of locomotor activity as during SD, but allowed long periods of undisturbed sleep. After 24 h SD response latencies slowed, and lapses increased significantly during rPVT performance when compared with baseline and EC conditions. During the first 3 h of the recovery period following 24 h SD, polysomnographic measures indicated sleepiness. Latency to fall asleep after 24 h SD was assessed six times during the first 3 h after SD. Rats fell asleep significantly faster immediately after SD, than after non‐SD baseline sessions. In conclusion, 24 h of SD in rats increased sleepiness, as indicated by polysomnography and the rMSLT, and impaired vigilance as measured by the rPVT. The rPVT closely resembles the human PVT test widely used in human sleep research and will assist investigation of the neurobiologic mechanisms that produce vigilance impairments after sleep disruption.     

Bedtime,shuteye time and electronic media: sleep displacement is a two‐step process

This study argues that going to bed may not be synonymous with going to sleep, and that this fragmentation of bedtime results in a two‐step sleep displacement. We separated bedtime (i.e. going to bed) from shuteye time (i.e. attempting to go to sleep once in bed) and assessed the prevalence of electronic media use in both time slots. A convenience sample of 338 adults (aged 18–25 years, 67.6% women) participated in an online survey. Results indicated a gap of 39 min between bedtime and shuteye time, referred to as ‘shuteye latency’. Respondents with a shuteye latency of, respectively, ≤30 min, ≤1 or >1 h, were 3.3, 6.1 and 9.3 times more likely to be rated as poor sleepers compared to those who went to sleep immediately after going to bed. Before bedtime, volume of electronic media use (17 h 55 min per week) was higher than non‐media activities (14 h per week), whereas the opposite was true after bedtime (media = 3 h 41 min, non‐media = 7 h 46 min). Shuteye latency was related exclusively to prebedtime media use. Findings confirmed the proposed fragmentation of bedtime. Sleep displacement should therefore be redefined as a two‐step process, as respondents not only engage in the delay of bedtime, but also in the delay of shuteye time once in bed. Theoretical, methodological and practical implications are discussed.     

Disturbed sleep in attention‐deficit hyperactivity disorder (ADHD) is not a question of psychiatric comorbidity or ADHD presentation

Attention‐deficit hyperactivity disorder (ADHD) is a heterogeneous psychiatric disorder with three different presentations and high levels of psychiatric comorbidity. Serious sleep complaints are also common, but the role of the presentations and comorbidity in sleep is under‐investigated in ADHD. Consequently, the goal of the study was to investigate sleep problems in medicine‐naive school‐aged children (mean age = 9.6 years) with ADHD compared to controls using objective methods and to examine the role of comorbidity and presentations. Ambulatory polysomnography results suggested that children with ADHD (n = 76) had significantly more sleep disturbances than controls (n = 25), including a larger percentage of rapid eye movement (REM) sleep and more sleep cycles, as well as lower mean sleep efficiency, mean non‐REM (NREM) sleep stage 1 and mean NREM sleep stage 3. No significant between‐group differences were found on the multiple sleep latency test. Stratifying for comorbidity in the ADHD group did not reveal major differences between groups, but mean sleep latency was significantly longer in children with ADHD and no comorbidity compared to controls (36.1 min; SD = 30.1 versus 22.6 min; SD = 15.2). No differences were found between ADHD presentations. Our results support the presence of night‐time sleep disturbances in children with ADHD. Poor sleep does not appear to be attributable to comorbidity alone, nor do sleep disturbances differ within ADHD presentations.     

多次睡眠潜伏期试验方法与临床应用

目的：研究多次睡眠潜伏期试验（muhiple sleep latency test MSLT）方法和操作步骤。方法：应用多导睡眠图（PSG）进行多次睡眠潜伏期试验，分析多次试验的睡眠次数、睡眠潜伏期和REM出现次数。结果：该方法取得了较好的临床应用效果。结论：MSLT对发作性睡病、阻塞性睡眠呼吸暂停、原发性嗜睡症和睡眠中周期性腿动等疾病的诊断和鉴别诊断具有重要参考价值。     

Concordance of actigraphy with polysomnography in children with and without attention‐deficit/hyperactivity disorder

This study sought to: (1) compare actigraphy‐derived estimated sleep variables to the same variables based on the gold‐standard of sleep assessment, polysomnography; (2) examine whether the correlations between the measures differ between children with attention‐deficit/hyperactivity disorder and typically developing children; and (3) determine whether these correlations are altered when children with attention‐deficit/hyperactivity disorder are treated with medication. Participants (24 attention‐deficit/hyperactivity disorder; 24 typically developing), aged 6–12 years, completed a 1‐week baseline assessment of typical sleep and daytime functioning. Following the baseline week, participants in the attention‐deficit/hyperactivity disorder group completed a 4‐week blinded randomized control trial of methylphenidate hydrochloride, including a 2‐week placebo and 2‐week methylphenidate hydrochloride treatment period. At the end of each observation (typically developing: baseline; attention‐deficit/hyperactivity disorder: baseline, placebo and methylphenidate hydrochloride treatment), all participants were invited to a sleep research laboratory, where overnight polysomnography and actigraphy were recorded concurrently. Findings from intra‐class correlations and Bland–Altman plots were consistent. Actigraphy was found to provide good estimates (e.g. intra‐class correlations >0.61) of polysomnography results for sleep duration for all groups and conditions, as well as for sleep‐onset latency and sleep efficiency for the typically developing group and attention‐deficit/hyperactivity disorder group while on medication, but not for the attention‐deficit/hyperactivity disorder group during baseline or placebo. Based on the Bland–Altman plots, actigraphy tended to underestimate for sleep duration (8.6–18.5 min), sleep efficiency (5.6–9.3%) and sleep‐onset latency, except for attention‐deficit/hyperactivity disorder during placebo in which actigraphy overestimated (?2.1 to 6.3 min). The results of the current study highlight the importance of utilizing a multimodal approach to sleep assessment in children with attention‐deficit/hyperactivity disorder.     

Daytime continuous polysomnography predicts MSLT results in hypersomnias of central origin

In the diagnostic work‐up of hypersomnias of central origin, the complaint of excessive daytime sleepiness should be objectively confirmed by MSLT findings. Indeed, the features and diagnostic utility of spontaneous daytime sleep at 24 h continuous polysomnography (PSG) have never been investigated. We compared daytime PSG features to MSLT data in 98 consecutive patients presenting with excessive daytime sleepiness and with a final diagnosis of narcolepsy with cataplexy/hypocretin deficiency (n = 39), narcolepsy without cataplexy (n = 7), idiopathic hypersomnia without long sleep time (n = 19), and ‘hypersomnia’ with normal sleep latency at MSLT (n = 33). Daytime sleep time was significantly higher in narcolepsy‐cataplexy but similar in the other groups. Receiver operating characteristics (ROC) curves showed that the number of naps during daytime PSG predicted a mean sleep latency ≤8 min at MSLT with an area under the curve of 0.67 ± 0.05 (P = 0.005). The number of daytime sleep‐onset REM periods (SOREMPs) in spontaneous naps strikingly predicted the scheduled occurrence of two or more SOREMPs at MSLT, with an area under the ROC curve of 0.93 ± 0.03 (P < 10^?12). One spontaneous SOREMP during daytime had a sensitivity of 96% with specificity of 74%, whereas two SOREMPs had a sensitivity of 75%, with a specificity of 95% for a pathological REM sleep propensity at MSLT. The features of spontaneous daytime sleep well correlated with MSLT findings. Notably, the occurrence of multiple spontaneous SOREMPs during daytime clearly identified patients with narcolepsy, as well as during the MSLT.     

The effect of arousals during sleep onset on estimates of sleep onset latency

It is well established that insomniacs overestimate sleep-onset latency. Furthermore, there is evidence that brief arousals from sleep may occur more frequently in insomnia. This study examined the hypothesis that brief arousals from sleep influence the perception of sleep-onset latency. An average of four sleep onsets was obtained from each of 20 normal subjects on each of two nonconsecutive, counterbalanced, experimental nights. The experimental nights consisted of a control night (control condition) and a condition in which a moderate respiratory load was applied to increase the frequency of microarousals during sleep onset (mask condition). Subjective estimation of sleep-onset latency and indices of sleep quality were assessed by self-report inventory. Objective measures of sleep-onset latency and microarousals were assessed using polysomnography. Results showed that sleep-onset latency estimates were longer in the mask condition than in the control condition, an effect not reflected in objective sleep-stage scoring of sleep-onset latency. Furthermore, an increase in the frequency of brief arousals from sleep was detected in the mask condition, and this is a possible source for the sleep-onset latency increase perceived by the subjects. Findings are consistent with the concept of a physiological basis for sleep misperception in insomnia.     

Sleep quality is negatively related to video gaming volume in adults

Most literature on the relationship between video gaming and sleep disturbances has looked at children and adolescents. There is little research on such a relationship in adult samples. The aim of the current study was to investigate the association of video game volume with sleep quality in adults via face‐to‐face interviews using standardized questionnaires. Adults (n = 844, 56.2% women), aged 18–94 years old, participated in the study. Sleep quality was measured using the Pittsburgh Sleep Quality Index, and gaming volume was assessed by asking the hours of gaming on a regular weekday (Mon–Thurs), Friday and weekend day (Sat–Sun). Adjusting for gender, age, educational level, exercise and perceived stress, results of hierarchical regression analyses indicated that video gaming volume was a significant predictor of sleep quality (β = 0.145), fatigue (β = 0.109), insomnia (β = 0.120), bedtime (β = 0.100) and rise time (β = 0.168). Each additional hour of video gaming per day delayed bedtime by 6.9 min (95% confidence interval 2.0–11.9 min) and rise time by 13.8 min (95% confidence interval 7.8–19.7 min). Attributable risk for having poor sleep quality (Pittsburgh Sleep Quality Index > 5) due to gaming >1 h day was 30%. When examining the components of the Pittsburgh Sleep Quality Index using multinomial regression analysis (odds ratios with 95% confidence intervals), gaming volume significantly predicted sleep latency, sleep efficiency and use of sleep medication. In general, findings support the conclusion that gaming volume is negatively related to the overall sleep quality of adults, which might be due to underlying mechanisms of screen exposure and arousal.     

Sleep-promoting effects of intraperitoneally administered uridine in unrestrained rats

An intraperitoneal injection of 0.1 nmol uridine in rats resulted in a transient excess slow-wave sleep if administered shortly before onset of the dark period. The sleep latency was remarkably shortened. A small dose (0.01 nmol) and larger doses (1, 10, 100 nmol) caused no effect. Uridine at a dose of 0.1 nmol was entirely ineffective if injected shortly before onset of the light period, while it resulted in transient excess paradoxical sleep if injected at an early phase of the light period. It is concluded that uridine, if timely administered through a systemic route, may pass the blood-brain barrier to modulate sleep in rats.     

发作性睡病的临床特征及多次小睡潜伏期试验

目的：探讨发作性睡病的临床特征及多次小睡潜伏期试验(MSLT)在诊断发作性睡病中的作用。方法：对6例发作性睡病的诊断过程进行回顾性分析。结果：6例患者均有白天过度嗜睡．其中4例伴猝倒。首发症状为白天过度嗜睡5例。猝倒1例。以白天过度嗜睡就诊者3例，以猝倒就诊者3例。6例患者进行MSLT检查，所有患者平均睡眠潜伏期都小于5min．其中5例出现≥2次的睡眠始发REM睡眠(SOREMS)。结论：充分认识发作性睡病的临床特征是诊断的关键。对于临床表现不典型的病例，MSLT将有助于诊断。     

The recuperative value of brief and ultra-brief naps on alertness and cognitive performance

The aim of the study was to investigate the recuperative value of brief and ultra-brief naps following nocturnal sleep restriction. Sixteen young adult healthy sleepers participated in a repeated measures design comprising four experimental conditions: no nap, 30-s nap, 90-s nap and 10-min nap. On the evening preceding each laboratory session, participants limited their nocturnal sleep to between 24:00 and 05:00 h. Measures of subjective alertness, objective alertness, fatigue, vigour and cognitive performance were taken before the nap and at several intervals postnap. Consistent with our previous study (Tietzel and Lack 2001), the 10-min nap resulted in significantly improved alertness and cognitive performance relative to a no-nap control. There were no measurable improvements for the 30- and 90-s nap conditions relative to no nap, which suggests that the mechanism underlying the benefits of brief naps does not appear to be the onset of stage 1 sleep. Further research is required to investigate whether the benefits of brief naps are because of the onset of stage 2 or delta wave sleep, or a specific duration of sleep between 90 s and 10 min.     

短半衰期催眠药对失眠症患者白天多次睡眠潜伏期测定的影响

目的 :探讨两种短半衰期催眠药佐匹克隆和三唑仑对失眠患者白天多次睡眠潜伏期测定 (MSLT)的影响。方法 :按照ICD 10的诊断标准收集 2 2例非器质性失眠症患者 ,随机分为两组 ,在服用 0 5mg三唑仑或 15mg佐匹克隆前后 ,分别进行MSLT检测。结果 :两药均可使白天MSLT的平均睡眠潜伏期和前两次测定的睡眠潜伏期明显缩短 ,使REM睡眠增加。两药对MSLT的影响特点相似。结论 :催眠药物可使失眠患者白天的困倦程度明显增高 ,这可能与药物的受体后效应有关 ,与药物种类的关系不大。     

No objectively measured sleep disturbances in children with attention‐deficit/hyperactivity disorder

The main goal of this study was to gain more insight into sleep disturbances in children with attention‐deficit/hyperactivity disorder, using objective measures of sleep quality and quantity. The evidence for sleep problems in children with attention‐deficit/hyperactivity disorder thus far is inconsistent, which might be explained by confounding influences of comorbid internalizing and externalizing problems and low socio‐economic status. We therefore investigated the mediating and moderating role of these factors in the association between attention‐deficit/hyperactivity disorder and sleep problems. To control for the effects of stimulant medication use, all participants were tested free of medication. Sixty‐three children with attention‐deficit/hyperactivity disorder and 61 typically developing children, aged 6–13 years, participated. Sleep was monitored for one to three school nights using actigraphy. Parent and teacher questionnaires assessed symptoms of attention‐deficit/hyperactivity disorder, internalizing behaviour, oppositional defiant disorder and conduct disorder. Results showed no differences between the attention‐deficit/hyperactivity disorder and typically developing group in any sleep parameter. Within the attention‐deficit/hyperactivity disorder group, severity of attention‐deficit/hyperactivity disorder symptoms was not related to sleep quality or quantity. Moderation analyses in the attention‐deficit/hyperactivity disorder group showed an interaction effect between attention‐deficit/hyperactivity disorder symptoms and internalizing and externalizing behaviour on total sleep time, time in bed and average sleep bout duration. The results of our study suggest that having attention‐deficit/hyperactivity disorder is not a risk factor for sleep problems. Internalizing and externalizing behaviour moderate the association between attention‐deficit/hyperactivity disorder and sleep, indicating a complex interplay between psychiatric symptoms and sleep.     

Sleep latency testing as a time course measure of state arousal

The purpose of this study was to determine how long the effects of a brief period of physiological arousal persisted using repeated sleep latency testing and measurement of heart rate. Thirteen normal sleeping young adults spent two non-consecutive nights and the following days in the laboratory. On each day, subjects had five sleep latency measurements - at 09:00, 09:30, 10:00, 10:30, and 11:00 hours. The 09:00 test was a premanipulation baseline. Following this nap, subjects either walked for 5 min (on one day) or rested in bed for 10 min (on another day) prior to the 09:30 hours sleep latency test. Significant increases in sleep latency were found at 09:30, 10:00, and 11:00 hours following the single 5-min walk as compared with resting in bed (mean sleep latency after the walk was 11.7 min compared with 7.1 min for the resting condition). Heart rate was significantly higher throughout all of the postmanipulation naps following the walk. The elevated sleep latency is probably secondary to the changes in underlying physiological arousal as measured in this study by heart rate.     

Eszopiclone Improves Overnight Polysomnography and Continuous Positive Airway Pressure Titration: A Prospective, Randomized, Placebo-Controlled Trial

STUDY OBJECTIVES: To assess whether premedication with eszopiclone would improve sleep duration and continuity during polysomnography, thereby improving the quality of diagnostic and CPAP titration studies. DESIGN: Prospective, double-blinded, placebo-controlled trial SETTING: Academic, multidisciplinary sleep center. PATIENTS: 226 adult subjects undergoing polysomnography for suspected sleep disordered breathing; 113 received eszopiclone and 113 received placebo. INTERVENTIONS: Subjects received eszopiclone 3 mg or matching placebo before polysomnography. We compared sleep latency, efficiency, total sleep time, and apnea-hypopnea index between these groups. We also compared rates of inadequate studies, defined as insufficient sleep time (< 120 min or sleep efficiency < or = 70%) or incomplete CPAP titrations (> or = 5 events/h on the highest CPAP or complete intolerance). MEASUREMENTS AND RESULTS: Eszopiclone premedication significantly improved a number of measured variables. Eszopiclone reduced sleep latency (21.7 +/- 27.1 vs. 32.6 +/- 38.2 min, P = 0.014), improved sleep efficiency (87.6% +/- 10.8% vs. 78.1% +/- 15.6%, P < 0.001), reduced wake after sleep onset (39.2 +/- 31.9 vs. 64.5 +/- 45.4 min, P <0.001) and prolonged sleep time (346.5 +/- 53.1 vs. 312.2 +/- 64.2 min, P < 0.001). Sleep efficiencies < or = 70% were more common with placebo than medication (21.2% vs. 7.1%, P = 0.004). Eszopiclone facilitated improved CPAP titrations with fewer residual events (5.7 +/- 10.3 vs. 11.9 +/- 19.6, P = 0.02) and fewer incomplete titrations (31.1% vs. 48.0%, P = 0.04). Poor quality studies (46.0% vs. 26.5%, P = 0.004) were more common with placebo than with eszopiclone. There was a trend for more non-usable studies with placebo (7.1% vs. 2.7%, P = 0.22). Side effects were uncommon and did not differ between groups. CONCLUSION: Pretreatment with eszopiclone improves the quality of polysomnography and CPAP titration and decreases the need to repeat studies. Given the ever-growing demand for polysomnography and the need to improve efficiency, the routine use of nonbenzodiazepines as premedication for polysomnography should be considered.     

The interplay between daily affect and sleep: a 2‐week study of young women

Little attention has been paid to the relation between daily affect and sleep, as most prior studies have focused instead on the role of pathological mood in the context of sleep disturbance. However, understanding the transaction between normal variations in emotional experiences and sleep can shed light on the premorbid vulnerabilities that trigger the evolution of affect and sleep into more problematic states. The present study used a 2‐week daily sampling approach to examine the impact of day‐to‐day variations in positive and negative affect on nightly self‐reported sleep‐onset latency, sleep duration and sleep quality in a sample of young women. Hierarchical linear modelling revealed temporal relations between positive and negative affect states and sleep parameters. Specifically, different aspects of both positive and negative affect were uniquely predictive of sleep indices, with sadness and serenity acting as the most consistent predictors. Additionally, better sleep quality was predictive of greater happiness the following day. These results highlight the importance of how our daily emotional experiences influence our nightly sleep and, in turn, how our sleep has an impact on our daily affect. Moreover, our findings may offer insight into the progression of normative levels of affect and sleep as they develop into comorbid depression, anxiety and insomnia.     

Reference values and changes in infant sleep–wake behaviour during the first 12 months of life: a systematic review

This paper is a systematic review on the reference values and changes in infant sleep–wake behaviour during the first 12 months of life. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analysis (PRISMA). Seventy‐four papers were included, and the reference values and changes in sleep–wake behaviour during the first 12 months of life were identified. Sleep duration during the 24‐h period, and day and sleep periods during the night decreased over the first 12 months of life. Night wakings and bedtime/sleep‐onset time decreased, while the longest sleep period increased at night during the first 6 months. High discrepancy was noted between studies in the reference values of sleep–wake behaviour, while more congruence was noted regarding changes, especially those occurring in the first 6 months of life. Several methodological differences were identified between studies and may partially explain inconsistencies in the results, including the assessment of different sleep–wake behaviours, the focus on specific ages or age ranges, the use of self‐report, observational or direct measures, the recruitment of small or large representative samples, and the countries where the research was conducted. These aspects should be considered in future research and caution should be taken when generalizing results from studies with diverse methodological characteristics. Nonetheless, this review identifies normative reference values and the changes occurring in infant sleep–wake behaviour, and could inform both practitioners and researchers, helping them identify infants with sleep delays or problems.     

Oculomotor changes are associated to daytime sleepiness in the multiple sleep latency test

Sleep onsets in the diurnal multiple sleep latency test (MSLT), following different sleep lengths of the preceding night sleep (8, 5, 4, 3, 2, 1 h) and following the corresponding recovery nights, were considered for a study on changes of oculomotor activity during sleep onset. The study aimed to assess the individual time course in spontaneous blinks (SBs) and slow eye movements (SEMs) during the sleep onset period and also the relationship with sleep latencies in the MSLT. Group analyses compared oculomotor changes between conditions characterized by a different level of daytime sleepiness. The results show a clear inverse relation between the two oculomotor measures, with a linear SB decrease and quadratic SEM increase across the wake-sleep transition. A 150 s sample of SB and SEM activity at the start of MSLT trials correlates with individual subsequent sleep latency. Finally, mean changes in daytime sleepiness as measured by the MSLT are paralleled by coherent oculomotor changes, with a significant linear decrease of SB as sleepiness increases as a consequence of previous sleep reduction. Both individual and group results show that endogenous blinking is associated with moderate changes in daytime sleepiness.     

Assessing sleepiness in the rat: a multiple sleep latencies test compared to polysomnographic measures of sleepiness

Sleepiness following 6 h of sleep deprivation (SD) was evaluated with a rat multiple sleep latencies test (rMSLT), and the findings were compared to conventional polysomnographic measures of sleepiness. The 6 h of SD was produced by automated activity wheels, and was terminated at either the end of the light period or at the beginning of the dark period. The rMSLT consisted of 5 min wakefulness induced by sensory stimulation followed by 25 min of freedom to sleep. This procedure was repeated every 30 min for 3 h and was designed to minimize the amount of sleep lost due to the testing procedure. In separate rats, 6 h SD was followed by undisturbed recovery, allowing evaluation of conventional polysomnographic measures of sleepiness. Sleep onset latencies were reduced following SD, with recovery in the light (baseline = 8 min, 3 s versus post-SD = 1 min, 17 s) and dark period (baseline = 14 min, 17 s versus 7 min, 7 s). Sleep onset latencies were not altered by varying the duration criterion for the first sleep bout (i.e., sleep bout length criteria of 10, 20, 30, or 60 s were compared). Polysomnographic variables (non-rapid eye movement sleep episode duration, delta power, and number of awakenings) also provided reliable indirect measures of sleepiness, regardless of whether the recovery sleep occurred in the light or dark period. Evaluation of effect size indicated that the rMSLT was a strong measure of sleepiness, and was influenced by homeostatic, circadian, and illumination factors. The rMSLT provided a simple, objective, robust and direct measure of sleepiness that was as effective as conventional polysomnographic measures of sleepiness.     

Evaluation of antihistamine-related daytime sleepiness

The daytime sleepiness potentially associated with antihistamines was evaluated by the multiple sleep latency test (MSLT) in a study comparing terfenadine with placebo. According to a double-blind, randomized, cross-over design, 12 healthy men were given either 120 mg terfenadine or placebo once daily in the morning, for 3 consecutive days with a 5-day interval. EEG-polygraphic recordings were made each study day at 9:30 and 11:30 a.m., and 1:30, 3:30, and 5:30 p.m., and the tendency to fall asleep was measured. All mean stage-1 sleep latencies throughout the study failed to show any significant difference between terfenadine and placebo. Accordingly, psychomotor performance assessed by visual and auditory reaction time did not change after treatment. The results of this study confirmed that terfenadine does not induce daytime sleepiness as objectively measured by MSLT.