Acute sleep restriction effects on emotion responses in 30- to 36-month-old children

Early childhood is a period of dramatic change in sleep and emotion processing, as well as a time when disturbance in both domains are first detected. Although sleep is recognized as central in emotion processing and psychopathology, the great majority of experimental data have been collected in adults. We examined the effects of acute sleep restriction (nap deprivation) on toddlers' emotion expression. Ten healthy children (seven females; 30-36 months old) followed a strict sleep schedule (≥12.5 h time in bed per 24-h) for 5 days, before each of two randomly assigned afternoon emotion assessments following Nap and No-Nap conditions (resulting in an 11-day protocol). Children viewed emotion-eliciting pictures (five positive, three neutral, three negative) and completed puzzles (one solvable, one unsolvable). Children's faces were video-recorded, and emotion displays were coded. When sleep restricted, children displayed less confusion in response to neutral pictures, more negativity to neutral and negative pictures, and less positivity to positive pictures. Sleep restriction also resulted in a 34% reduction in positive emotion responses (solvable puzzle), as well as a 31% increase in negative emotion responses and a 39% decrease in confused responses (unsolvable puzzle). These findings suggest sleep is a key factor in how young children respond to their world. When sleep restricted, toddlers are neither able to take full advantage of positive experiences nor are they as adaptive in challenging contexts. If insufficient sleep consistently 'taxes' young children's emotion responses, they may not manage emotion regulation challenges effectively, potentially placing them at risk for future emotional/behavioral problems.     

Effects of cumulative sleep restriction on self‐perceptions while multitasking

This study addressed a rarely studied question of self‐perceptions of performance and overall functional state during cumulative sleep restriction and the ensuing recovery period. Twenty healthy male volunteers, aged 19–29 years, were divided into a sleep restriction group (n = 13) and a control group (n = 7). On the first 2 nights, the sleep restriction group had an 8‐h sleep opportunity that was restricted to 4 h for the next 5 nights, and then restored to 8 h for the last 2 nights. The control group had an 8‐h sleep opportunity each night. Each day participants accomplished 50‐min multitask sessions and gave self‐ratings in their connection. Similar to our previous findings on multitasking performance, self‐perceived task performance, sleepiness and mental fatigue impaired during the sleep restriction and returned to baseline during the recovery phase. Self‐perceived mental effort, tension, task difficulty and task pace showed no sensitivity to the sleep restriction. We concluded that sleep‐restricted individuals can probably make use of some self‐perceptions when assessing their ‘fitness for duty’. However, at the individual level these measures seem to be inaccurate in revealing actual performance impairments.     

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.     

Trait‐like characteristics of sleep EEG power spectra in adolescents across sleep opportunity manipulations

The electroencephalographic power spectra of non‐rapid eye movement sleep in adults demonstrate trait‐like consistency within participants across multiple nights, even when prior sleep deprivation is present. Here, we examined the extent to which this finding applies to adolescents who are habitually sleep restricted on school‐days and sleep longer on weekends. We evaluated 78 adolescents across three sleep restriction groups who underwent different permutations of adequate sleep (9 hr time‐in‐bed), sleep restriction (5 hr time‐in‐bed), afternoon naps (1 hr afternoon) and recovery sleep (9 hr time‐in‐bed) that simulate behaviour on school‐days and weekends. The control group comprised a further 22 adolescents who had 9 hr of sleep opportunity each night. Intra‐class correlation coefficients showed moderate to almost perfect within‐subject stability in electroencephalographic power spectra across multiple nights in both sleep restriction and control groups, even when changes to sleep macrostructure were observed. While nocturnal intra‐class correlation metrics were lower in the low‐frequency and spindle frequency bins in the sleep restriction compared with the control group, hierarchical clustering measures could still identify multi‐night electroencephalographic spectra as originating from the same individual. The trait‐like characteristics of electroencephalographic spectra from an adolescent remain identifiable despite the disruptive effects of multi‐night sleep restriction to sleep architecture.     

A 20-h recovery sleep after prolonged sleep restriction: some effects of competing in a world record-setting cinemarathon

SUMMARY  The recovery sleep of a 21-year-old normal woman was assessed after she had endured 11 1/2 days of sleep restriction in a world record-setting film-viewing marathon. An exceptional sleep debt was observed as indicated by an instanteous sleep onset, a high sleep efficiency, and a total sleep duration of over 20 hours. Other striking features of this recovery sleep were very short latencies to stages 3 and 4 sleep, return of Stage 4 sleep after 14.5 h, REM and SWS sleep rebound, and a linear increase in REM sleep efficiency across 14 consecutive REM-NREM episodes. Seven of nine home dreams reported after this recording contained competition themes, but none relating to the marathon films. Comparisons of the present results with those from subjects in previous record-setting events suggest possible explanations for the extremely long recovery sleep. Results also suggest that analyses of multiple consecutive sleep cycles may provide novel ways of assessing hypotheses about regulation of the REM-NREM cycle.     

Actigraphy‐assessed sleep during school and vacation periods: a naturalistic study of restricted and extended sleep opportunities in adolescents

School‐related sleep restriction in adolescents has been identified by studies comparing weekday and weekend sleep. This study compared weekday and vacation sleep to assess restricted and extended sleep opportunities. One‐hundred and forty‐six adolescents (47.3% male) aged 16.2 ± 1.0 years (M ± SD) from the general community wore an actigraph continuously for 4 weeks: the last week of a school term (Time‐E), the following 2‐week vacation, and the first week of the next term. Self‐reported sleep was assessed for each of the three time intervals, and chronotype was assessed using the Morningness–Eveningness Questionnaire at Time‐E. Daily actigraphy bedtime, rise‐time, time‐in‐bed, total sleep time, sleep onset latency, sleep efficiency, and % wake after sleep onset were analysed using latent growth curve modelling. The removal of school‐related sleep restriction was associated with an abrupt delay in sleep timing and increase in sleep duration. Subsequently, bedtime and rise‐time showed further linear delays throughout the vacation, while changes in time‐in‐bed were non‐significant. Sleep onset latency increased linearly, peaking in the middle of the second vacation week. Across the first vacation week, total sleep time and sleep efficiency linearly decreased, while % wake after sleep onset increased. These changes stabilized during the second vacation week. Older age and eveningness were associated with later bedtime and rise‐time, whilst females had longer time‐in‐bed, total sleep time and sleep onset latency. Compared with school days, sleep during the vacation was characterized by later timing, longer duration, lower quality and greater variability. Recovery from school‐related sleep restriction appeared to be completed within the 2 weeks of naturalistic extended sleep.     

Sleep hygiene and actigraphically evaluated sleep characteristics in children with ADHD and chronic sleep onset insomnia

In the present study we investigated sleep hygiene and actigraphically evaluated sleep in 74 medication‐naïve children, aged 6–12 years, with rigorously diagnosed attention‐deficit/hyperactivity disorder (ADHD) and chronic sleep onset insomnia (ADHD‐SOI) and 23 ADHD controls without insomnia (ADHD‐noSOI). Between‐group differences were analysed for lights out (sleep log), actigraphically evaluated sleep onset, sleep latency, total sleep duration, actual sleep time and sleep hygiene as measured with the Children's Sleep Hygiene Scale. We found a significant difference (P < 0.001) in mean (±SD) sleep onset between the ADHD‐SOI group (21:49 ± 0:56 h) and ADHD‐noSOI groups (20:41 ± 0:45 h). Sleep latency was significantly (P < 0.001) longer in ADHD‐SOI (00:53 ± 0:25 h) compared to ADHD‐noSOI (00:26 ± 0:25 h). The difference in total sleep duration between ADHD‐SOI (9:42 ± 0:44 h) and ADHD‐noSOI (10:09 ± 0:43 h) was not significantly different (P = 0.18). The group difference in actual sleep time was also not significant (8:43 ± 0:52 h in ADHD‐SOI versus 9:13 ± 1:16 h; P = 0.40). There was no significant difference (P = 0.17) in mean (±SD) total sleep hygiene score between the ADHD‐SOI (56.4 ± 10.5) and ADHD‐noSOI groups (53.0 ± 10.6). We conclude that there were differences in sleep onset and sleep latency in ADHD children with chronic SOI and those without insomnia; however, sleep hygiene practices were similar and did not relate to sleep characteristics.     

Low‐grade albuminuria in children with obstructive sleep apnea

Small urinary protein loss (low‐grade albuminuria or microalbuminuria) may reflect altered permeability of the glomerular filtration barrier. In the present study, it was hypothesized that children with obstructive sleep apnea have an increased risk of microalbuminuria compared with control subjects without sleep‐disordered breathing. Albumin‐to‐creatinine ratio was measured in morning spot urine specimens collected from consecutive children with or without snoring who were referred for polysomnography. Three groups were studied: (i) control subjects (no snoring, apnea–hypopnea index < 1 episode h^?1; n = 31); (ii) mild obstructive sleep apnea (snoring, apnea–hypopnea index = 1–5 episodes h^?1; n = 71); and (iii) moderate‐to‐severe obstructive sleep apnea (snoring, apnea–hypopnea index > 5 episodes?h^?1; n = 27). Indications for polysomnography in control subjects included nightmares, somnambulism and morning headaches. An albumin‐to‐creatinine ratio > median value in the control group (1.85 mg of albumin per g of creatinine) was defined as elevated. Logistic regression analysis revealed that children with moderate‐to‐severe obstructive sleep apnea, but not those with mild obstructive sleep apnea, had increased risk of elevated albumin‐to‐creatinine ratio relative to controls (reference) after adjustment for age, gender and presence of obesity: odds ratio 3.8 (95% confidence interval 1.1–12.6); P = 0.04 and 1.5 (0.6–3.7); P > 0.05, respectively. Oxygen desaturation of hemoglobin and respiratory arousal indices were significant predictors of albumin‐to‐creatinine ratio (r = 0.31, P = 0.01; and r = 0.43, P < 0.01, respectively). In conclusion, children with moderate‐to‐severe obstructive sleep apnea are at significantly higher risk of increased low‐grade excretion of albumin in the morning urine as compared with control subjects without obstructive sleep apnea. These findings may reflect altered permeability of the glomerular filtration barrier related to nocturnal hypoxemia and sympathetic activation which are induced by obstructive sleep apnea.     

Effects of late‐night short‐sleep on in‐home polysomnography: relation to adult age and sex

Bedtime is frequently delayed by many factors in life, and a homeostatic response to the delay may compensate partly for increased time awake and shortened sleep. Because sleep becomes shorter with age and women complain of disturbed sleep more often than men, age and sex differences in the homeostatic response to a delayed bedtime may modify the homeostatic response. The purpose of the present study was to investigate the effect of late‐night short‐sleep (3 h with awakening at about 07:00 hours) on in‐home recorded sleep in men and women in two age groups (20–30 and 65–75 years). Results (N = 59) showed that late‐night short‐sleep was associated with an increase in percentage of N3 sleep and a decrease in percentage of rapid eye movement sleep, as well as decreases in several measures of sleep discontinuity and rapid eye movement density. Men showed a smaller decrease in percentage of rapid eye movement sleep than women in response to late‐night short‐sleep, as did older individuals of both sexes compared with younger. Older men showed a weaker percentage of N3 sleep in response to late‐night short‐sleep than younger men. In general, men showed a greater percentage of rapid eye movement sleep and a lower percentage of N3 sleep than women, and older individuals showed a lower percentage of N3 sleep than younger. In particular, older men showed very low levels of percentage of N3 sleep. We conclude that older males show less of a homeostatic response to late‐night short‐sleep. This may be an indication of impaired capacity for recovery in older men. Future studies should investigate if this pattern can be linked to gender‐associated differences in morbidity and mortality.     

A review of sleep disturbance in children and adolescents with anxiety

The present review examines the relations between sleep disturbance and anxiety in children and adolescents. The review begins with a detailed discussion of normative developmental trends in sleep, and the relation between sleep quality and emotion dysregulation in children. The extant literature on sleep disturbance in clinically anxious children with a focus on subjective versus objective measures of sleep is then summarized in detail. Finally, a review of the reciprocal relationship between sleep and emotion regulation is provided. The available research suggests that sleep disturbance is quite prevalent in children with anxiety disorders, although the directionality of the association between sleep disturbance and anxiety in children remains unclear. Despite this limitation, a reciprocal relationship between sleep quality and anxiety appears to be well established. Research using objective measures of sleep quality (e.g. polysomnography, sleep actigraphy, sleep bruxism) is warranted to better understand this relation. Further, complicating factors such as the environment in which sleep quality is measured, the developmental stage of participants, varying severity of anxiety and the timeframe during which assessment takes place should all be considered when examining sleep disturbance in this population.     

Attachment representations,sleep quality and adaptive functioning in preschool age children

Both the attachment system and sleep are considered to be important biopsychosocial regulators of development and of adaptive functioning in children, and there is a substantial literature suggesting that the two systems may be mutually influencing. To date, however, the bulk of research attempting to link these systems has focused on infancy and the results of empirical studies are mixed. Thirty-nine preschool children participated in this study (valid sleep data for 34 cases). Attachment representations were assessed using the Attachment Story Completion Task (ASCT) and sleep was assessed using objective (i.e., actigraphy) measures. Analyses revealed that the coherence of child narratives and security scored from the ASCT were related to sleep quality indices (e.g., Sleep Activity, Wake Minutes after Sleep Onset, Sleep Efficiency). Additional analyses examined external correlates of attachment representations and tested possible interactions of attachment and sleep. No significant mediated interactions across attachment and sleep domains were found. Although the direction of effects cannot be determined, the results suggest that parent–child relationship and sleep organization are intertwined for preschool age children and the joint effects of these biopsychosocial regulators should be studied further.     

Sex differences in the association between sleep duration, diet and body mass index: a birth cohort study

Sex differences in the effects of sleep duration on dietary intake and eating behaviours were examined prospectively in relation to overweight/obesity at ages 6 and 7. Using data from a representative sample (QLSCD 1998-2010) of children born in the province of Québec (Canada), 1106 children were followed to age 6 and 1015 to 7years. Average nocturnal sleep duration was surveyed annually from 2.5-6years, food-frequency and eating behaviour questionnaires were administered at age 6, and body weight and height were measured at 6 and 7years. Associations were examined longitudinally and mediation examined with adjustments for potential confounders. In boys and girls, shorter sleep duration patterns were associated significantly with less favourable dietary intakes at 6years: boys consumed vegetables and fruits less frequently and meats/alternatives more frequently than boys with longer sleep patterns; and girls consumed vegetables, fruits and milk products less frequently and soft-drinks more frequently than girls with longer sleep patterns. However, boys with shorter sleep patterns were also more likely to eat at irregular hours or to eat too much/fast at 6years. These behaviours, and not dietary intake, mediated an inverse association between sleep duration and overweight/obesity in boys. Sleep duration did not associate with any problem eating behaviours or overweight/obesity in girls. Shorter sleep in early childhood appears to associate with problematic eating behaviours in boys and diet quality in both sexes, regardless of an association with overweight/obesity. This is important for public health and should be considered in relation to other diet-related diseases.     

Unique sleep‐stage transitions determined by obstructive sleep apnea severity,age and gender

In obstructive sleep apnea, patients’ sleep is fragmented leading to excessive daytime sleepiness and co‐morbidities like arterial hypertension. However, traditional metrics are not always directly correlated with daytime sleepiness, and the association between traditional sleep quality metrics like sleep duration and arterial hypertension is still ambiguous. In a development cohort, we analysed hypnograms from mild (n = 209), moderate (n = 222) and severe (n = 272) obstructive sleep apnea patients as well as healthy controls (n = 105) from the European Sleep Apnea Database. We assessed sleep by the analysis of two‐step transitions depending on obstructive sleep apnea severity and anthropometric factors. Two‐step transition patterns were examined for an association to arterial hypertension or daytime sleepiness. We also tested cumulative distributions of wake as well as sleep‐states for power‐laws (exponent α) and exponential distributions (decay time τ) in dependency on obstructive sleep apnea severity and potential confounders. Independent of obstructive sleep apnea severity and potential confounders, wake‐state durations followed a power‐law distribution, while sleep‐state durations were characterized by an exponential distribution. Sleep‐stage transitions are influenced by obstructive sleep apnea severity, age and gender. N2 → N3 → wake transitions were associated with high diastolic blood pressure. We observed higher frequencies of alternating (symmetric) patterns (e.g. N2 → N1 → N2, N2 → wake → N2) in sleepy patients both in the development cohort and in a validation cohort (n = 425). In conclusion, effects of obstructive sleep apnea severity and potential confounders on sleep architecture are small, but transition patterns still link sleep fragmentation directly to obstructive sleep apnea‐related clinical outcomes like arterial hypertension and daytime sleepiness.     

Sleep spindle characteristics and sleep architecture are associated with learning of executive functions in school‐age children

The macro‐ and microstructural characteristics of sleep electroencephalography have been associated with several aspects of executive functioning. However, only a few studies have addressed the association of sleep characteristics with the learning involved in the acquisition of executive functions, and no study has investigated this for planning and problem‐solving skills in the developing brain of children. The present study examined whether children's sleep stages and microstructural sleep characteristics are associated with performance improvement over repeated assessments of the Tower of Hanoi task, which requires integrated planning and problem‐solving skills. Thirty children (11 boys, mean age 10.7 years, SD = 0.8) performed computerized parallel versions of the Tower of Hanoi three times across 2 days, including a night with polysomnographically assessed sleep. Pearson correlations were used to evaluate the associations of Tower of Hanoi solution time improvements across repeated assessments with sleep stages (% of total sleep time), slow‐wave activity, and fast and slow spindle features. The results indicated a stronger performance improvement across wake in children with more Stage N2 sleep and less slow‐wave sleep. Stronger improvements across sleep were present in children in whom slow spindles were more dense, and in children in whom fast spindles were less dense, of shorter duration and had less power. The findings indicate that specific sleep electroencephalography signatures reflect the ability of the developing brain to acquire and improve on integrated planning and problem‐solving skills.     

Sleep‐disordered breathing in children is associated with impairment of sleep stage‐specific shift of cardiac autonomic modulation

We examined the effects of sleep stages and sleep‐disordered breathing (SDB) on autonomic modulation in 700 children. Apnea hypopnea index (AHI) during one 9 h night‐time polysomnography was used to define SDB. Sleep stage‐specific autonomic modulation was measured by heart rate variability (HRV) analysis of the first available 5 min RR intervals from each sleep stage. The mean [standard deviation (SD)] age was 112 (21) months (49% male and 25% non‐Caucasian). The average AHI was 0.79 (SD = 1.03) h^?1, while 73.0%, 25.8% and 1.2% of children had AHI <1 (no SDB), 1–5 (mild SDB) and ≥5 (moderate SDB), respectively. In the no SDB group, the high frequency (HF) and root mean square SD (RMSSD) increased significantly from wake to Stage 2 and slow wave sleep (SWS), and then decreased dramatically when shifting into rapid eye movement (REM) sleep. In the moderate SDB group, the pattern of HRV shift was similar to that of no SDB. However, the decreases in HF and RMSSD from SWS to REM were more pronounced in moderate SDB children [between‐group differences in HF (?24% in moderate SDB versus ?10% in no SDB) and RMSSD (?27% versus ?12%) were significant (P < 0.05)]. The REM stage HF is significantly lower in the moderate SDB group compared to the no SDB group [mean (standard error): 4.49 (0.43) versus 5.80 (0.05) ms², respectively, P < 0.05]. Conclusions are that autonomic modulation shifts significantly towards higher parasympathetic modulation from wake to non‐rapid eye movement sleep, and reverses to a less parasympathetic modulation during REM sleep. However, the autonomic modulation is impaired among children with moderate SDB in the directions of more reduction in parasympathetic modulation from SWS to REM sleep and significantly weaker parasympathetic modulation in REM sleep, which may lead to higher arrhythmia vulnerability, especially during REM sleep.     

Actigraphic sleep fragmentation,efficiency and duration associate with dietary intake in the Rotterdam Study

Short self‐reported sleep duration is associated with dietary intake and this association may partly mediate the link between short sleep and metabolic abnormalities. Subjective sleep measures, however, may be inaccurate and biased. The objective of this study was to evaluate the associations between actigraphic measures of sleep fragmentation, efficiency and duration and energy and macronutrient intakes. We used data from a subgroup of 439 participants of the population‐based cohort, Rotterdam Study. Sleep was assessed using 7‐day actigraphy and sleep diaries, and dietary data with a validated food frequency questionnaire. We assessed the associations of actigraphic sleep parameters with dietary intake using multivariable linear regression models. Higher sleep fragmentation was associated with 4.19 g lower carbohydrate intake per standard deviation of fragmentation {β [95% confidence interval (CI) = ?4.19 (?8.0, ?0.3)]; P = 0.03}. Each additional percentage increase in sleep efficiency was associated with 11.1 kcal lower energy intake [β (95% CI) = ?11.1 (?20.6, ?1.7); P = 0.02]. Furthermore, very short sleep duration (<5.5 h) was associated with 218.1 kcal higher energy intake [β (95% CI = 218.06 (33.3, 402.8), P = 0.02], relative to the reference group (≥6.5 to <7.5 h). We observed associations between higher sleep fragmentation with lower carbohydrate intake, and both lower sleep efficiency and very short sleep duration (<5 h) with higher energy intake. The association between sleep and higher energy intake could mediate, in part, the link between short sleep or sleep fragmentation index and metabolic abnormalities.     

Apnea‐related sleep fragmentation and poor vigilance in children with well‐controlled asthma

It has been reported that sleep problems and neurocognitive deficit in asthmatic children is prevalent. However, systematic studies on these problems in stable asthma using polysomnography have rarely been performed. We therefore investigated sleep and neurocognitive functioning in children with well‐controlled asthma. Forty‐three children with well‐controlled, stable asthma and 31 controls (age range: 6–9 years) were enrolled in the study. Subjects were questioned for daytime sleepiness using the Paediatric Daytime Sleepiness Scale. Complete overnight polysomnography and neurocognitive function tests were performed on all subjects. Children with stable asthma had lower pulmonary function in comparison to their age‐matched controls. Asthmatic children had a higher apnea–hypopnea index (P < 0.001) and apnea–hypopnea‐related arousal index (P < 0.001) as compared with non‐asthmatics. Deep sleep was decreased in asthmatics (P = 0.001). In the vigilance test, the mean number of correct answers was lower (P = 0.005) and the mean reaction time was slower (P = 0.002) in asthmatic children. A hierarchical multiple linear regression showed that deep sleep and apnea–hypopnea‐related arousal index were significant predictors of vigilance. The data suggest that the prevalence of paediatric sleep‐disordered breathing and sleep fragmentation could be very high among children with well‐controlled asthma. Moreover, vigilance, the ability to maintain attention and alertness, was worse in stable asthmatic children when compared with healthy controls. Sleep‐disordered breathing should be checked even in stable asthmatic children as they are at risk for developing neurobehavioural deterioration associated with frequent arousals during sleep. Furthermore, early treatment for asthma may be required in order to prevent airway remodelling that could cause sleep problems.