Continuity and change in poor sleep from childhood to early adolescence

Trajectories of actigraphy-derived sleep duration, quality, and variability from childhood to adolescence: downstream effects on mental health

STUDY OBJECTIVES

We examined growth trajectories of four actigraphy-derived sleep parameters (sleep minutes, sleep efficiency, and variability in sleep minutes and efficiency across a week of assessments) across childhood and adolescence and examined individual differences in trajectories according to participants' race/ethnicity and sex. We also assessed the predictive effect of growth trajectories of sleep parameters on growth trajectories of mental health outcomes and moderation by race and sex.

METHOD

Youth (N = 199, 49% female, 65% white, 32% black, 3% biracial) and their parents participated in five waves of data (M ages were 9, 10, 11, 17, and 18 across waves). Participants were from a diverse range of socioeconomic backgrounds.

RESULTS

Across participants, sleep minutes, sleep efficiency, and variability in sleep minutes and efficiency demonstrated significant linear change across childhood and adolescence. Whereas sleep duration shortened over time, sleep efficiency improved. Youth exhibited increases in night-to-night variability in sleep minutes and reductions in night-to-night variability in sleep efficiency. Highlighting the importance of individual differences, some race- and sex-related effects emerged. Black youth and male youth experienced steeper declines in their sleep duration across development relative to their respective counterparts. Black youth also demonstrated smaller improvements in sleep efficiency and greater variability in sleep efficiency compared to white youth. Finally, trajectories of sleep efficiency and variability in sleep minutes predicted trajectories of internalizing symptoms and externalizing behaviors.

CONCLUSIONS

Findings showed significant changes in developmental trajectories of four sleep parameters across childhood and adolescence. We discuss the empirical and translational implications of the findings.

Childhood sleep: assessments, risk factors, and potential mechanisms

BACKGROUND

Sleep problem is a highly prevalent health issue among pediatric populations across the world. In this review, we aimed to identify risk factors contributing to sleep deficiency and poor sleep hygiene in children. Potential biological, psychosocial, and environmental mechanisms as well as research gaps in the literature are also discussed.

DATA SOURCES

A comprehensive search for relevant English language full-text, peer-reviewed publications was performed focusing on pediatric sleep studies from prenatal to childhood and adolescence in a variety of indexes in PubMed, SCOPUS, and Psych Info. Both relevant data based and systematic reviews are included.

RESULTS

This paper summarizes many risk factors for childhood sleep problems, including biological (e.g., genetics, gender, age and puberty, prenatal factors, postnatal factors); nutritional (e.g., macronutrients, micronutrients, omega-3 fatty acids, obesity); environmental (e.g., heavy metals, noise, light, air pollution); interpersonal (e.g., family, exposure to violence, screen media use, physical injury); and community/socioeconomic variables (e.g., racial/ethnicity and cultural factors, neighborhood conditions and socioeconomic status, school factors, public health disasters/emergencies), to better understand the development of sleep problems in children.

CONCLUSIONS

Poor childhood sleep is a multifactorial issue affected by a wide range of prenatal and early-life biological, environmental, and psychosocial risk factors and contributors. A better understanding of these risk factors and their mechanisms is an important first step to develop future research and prevention programs focusing on pediatric sleep problems.

From early birds to night owls: a longitudinal study of actigraphy-assessed sleep trajectories during the transition from pre- to early adolescence

STUDY OBJECTIVES

Pre- and early adolescence are believed to constitute periods of important age-related changes in sleep. However, much of the research on these presumed developmental changes has used cross-sectional data or subjective measures of sleep, limiting the quality of the evidence. In addition, little is known about the development of certain features of the sleep-wake cycle pertaining to regularity (e.g. weekend-weekday differences and intra-individual variability) or circadian rhythms (e.g. sleep midpoint).

METHODS

This study examined the sleep trajectories of 128 typically developing youth (69 girls) from ages 8 to 12 years on four sleep characteristics: sleep onset, sleep offset, total sleep time (TST), and sleep midpoint. For each of these characteristics, actigraphy-derived estimates of typical (i.e. mean) sleep and sleep regularity were obtained at each time point. Multilevel growth curves were modeled.

RESULTS

Overall, the sleep-wake cycle significantly changed between 8 and 12 years. Mean sleep onset, offset and midpoint exhibited an ascending curvilinear growth pattern that shifted later with age, while mean TST decreased linearly. Weekend-weekday differences (social jetlag) for sleep offset and midpoint became more pronounced each year. Weekday TST was longer than weekend TST, though this difference became smaller over time. Finally, intra-individual variability increased over time for all sleep characteristics, with variability in TST ascending curvilinearly. Important between-person and sex differences were also observed.

CONCLUSION

This study reveals the marked changes that occur in the sleep of typically developing pre- and early adolescents. We discuss the potential implications of these trajectories.

Sleep and psychiatric symptoms in young child psychiatric outpatients - a Follow-up study

BACKGROUND

Knowledge of the continuity of sleep problems and the associations between sleep and psychiatric symptoms in child psychiatric patients is scarce.

OBJECTIVES

To investigate the persistency of sleep problems and how sleep at preschool age predicts sleep problems and psychiatric symptoms at school age in child psychiatric patients.

METHODS

Participants (n = 68) were child psychiatry outpatients at Helsinki University Hospital in 2015-2017. Caregivers evaluated sleep with the Sleep Disturbance Scale for Children (SDSC) and psychiatric symptoms with the Child Behavior Checklist (CBCL) at baseline (age 4-7 years) and again at follow-up (age 8-13 years). Family background information was collected at both time points.

RESULTS

Sleep problems at preschool age predicted sleep problems at school age (R2Adjusted = .48, p < .001). Persistent sleep problems associated strongly with the intensity of psychiatric symptoms (p = .001). Internalizing symptoms were predicted by sleep problems (p = .038) even after controlling for age, sex, and psychiatric symptoms at preschool age.

CONCLUSION

Sleep problems are prevalent and persistent and relate to psychiatric symptoms in children treated at child psychiatry clinics. These results emphasize the need for identification and treatment of sleep problems in these children.

Analyzing sleep status in children with acute leukemia

BACKGROUND

Quality sleep is essential for physical and mental health. We aimed to analyze sleep disorders in children with acute leukemia and explore associated factors.

METHODS

General data and sleep disorders in children with acute leukemia during chemotherapy were collected by general questionnaires, Children's Sleep Disorders Scale and the Parenting Stress Index-short form.

RESULTS

In total, 173 valid questionnaires were collected. The total Sleep Disorder Scale score > 39 is considered a sleep disorder, while sleep disorders accounted for 45.66% (79/173). In the cohort, 167 children had acute lymphoblastic leukemia, with 40.12% (67/167) having sleep disorders, while six children had acute non-lymphoblastic leukemia, with 50.00% (3/6) having sleep disorders. Single- and multi-factor regression analyses of age, gender, number of children in the family, and time spent using electronic devices showed that factors influencing sleep disorders in these children were mainly parental scolding and adenoid hypertrophy. Children with sleep disorders had more parental stress than those without sleep disorders (P < 0.05).

CONCLUSIONS

The high incidence of sleep disorders in children with acute leukemia is related to airway conditions and parental behaviors. Sleep disorders in children can increase parenting stress. Factors potentially affecting sleep quality should be addressed as early as possible, while parental education should be strengthened to better facilitate the physical and psychological recovery of their children.

Sleep troubles in adolescence relate to future initiation of ENDS USE: A longitudinal cohort design using the PATH study waves 4.5–5 (2017–2019)

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First longitudinal study on the association between sleep trouble and ENDS use.

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Past year sleep trouble increased risk of initiating ENDS use in following year.

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Healthy sleep serves as a protective factor against ENDS uptake for youth.

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Nearly half of youths aged 12–17, experienced sleep troubles during wave 4.5.

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Sleep classes for youth/delayed school start times may help deter future ENDS use.

In a recent study, we demonstrated a relationship between self-reported sleep deprivation and youth susceptibility to initiate electronic nicotine delivery systems (ENDS) use; however, we were hampered by cross-sectional data. This study builds on our previous work by performing secondary analysis using the nationally representative Population Assessment of Tobacco and Health study datasets from wave 4.5 (2017–2018) and wave 5 (2018–2019) among respondents aged 12–17. Using a longitudinal cohort design, we assessed the extent self-reported sleep troubles at wave 4.5 related to transition from never-to-ever ENDS use by wave 5. We assessed youth who reported never having used any type of tobacco previously and who reported not using alcohol or other illicit substances the previous year. We ran four Poisson regression models on the dependent variable never-to-ever ENDS users at wave 5 and self-reported sleep troubles in the past year at wave 4.5. We controlled for demographic and sociographic factors and, in our final model, tobacco availability in home, exposure to ENDS advertising on social media, past year anxiety, depression, body mass index, physical activity, close friends that use ENDS, perceived harm of ENDS, school performance, sensation seeking, and the susceptibility of youth to initiate ENDS. Even when controlling for these factors, sleep troubles at wave 4.5 significantly and positively related to ENDS initiation by wave 5 (Past year sleep trouble: RR = 1.48 95 % CI = [1.14–1.93]). This key and novel finding has important implications for preventing youth ENDS use via protective self-care and social-environmental approaches.

The multidimensionality of sleep in population‐based samples: a narrative review

The identification of optimal sleep duration recommendations for the general population has long been an important goal on the public health agenda, as both short and long sleep duration have been linked to unfavourable health outcomes. Yet, sleep is more than duration alone and can be described across multiple domains, such as timing, regularity, satisfaction, alertness, and efficiency. We reviewed observational population‐based studies that examined differences in age, sex, and origin across multiple dimensions of sleep. Reviewed literature suggests an increasing prevalence of insomnia symptoms, shorter and less deep sleep in old age. Overall, women report poorer sleep quality than men despite objective measures revealing shorter and more fragmented sleep in men. Minorities generally have poorer quantity and quality of sleep, but multi‐ethnic studies have reported mixed results regarding the subjective experience of sleep. In sum, effects of age, sex and origin differ across sleep dimensions, thereby suggesting that the multidimensionality of sleep and how these different aspects interact should be studied across individuals. Studies should include both self‐reported measures and objective assessments in diverse population‐based samples, as both aspects are important to understand sleep health in the general population. Data‐driven descriptions could provide researchers and clinicians with insights into how well individuals are sleeping and offer concrete targets for promotion of sleep health across the population.

Sleep deprivation and adolescent susceptibility to vaping in the United States

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Adolescent sleep deprivation is associated with susceptibility to ENDS use.

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Less than 6 h sleep relates to higher perceived likelihoods of trying ENDS.

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ENDS prevention efforts may benefit by incorporating sleep hygiene measures.

Sleep deprivation may be a contributing factor to adolescents’ willingness to experiment with substance use, including electronic nicotine devices (ENDS). While it is generally accepted that nicotine has a negative overall effect on sleep, no studies have yet explored whether sleep deprivation may contribute to adolescents’ initiation of ENDS use. The purpose of this study is to explore whether sleep deprivation is associated with adolescents’ self-reported susceptibility to initiating ENDS use in the next month. Respondents were 1,100 adolescents aged 13–17 across the United States who participated in the Vaping Attitudes Youth Perspectives Survey (VAYPS). We used logistic regression to examine cross-sectional associations between self-reported average sleep duration and self-reported likelihood of trying ENDS in the future. Results of the three logistic regression models show that adolescents who reported getting less than six hours of sleep per night were associated with greater odds of reporting any likelihood to try a vape in the next 30 days even when controlling for demographics and potential confounders (<6hrs sleep: OR = 2.63, 95% CI 1.30–5.31). Future research on the association between sleep deprivation and ENDS use among adolescents will benefit from using longitudinal approaches to better understand causality.

Neural correlates of sleep quality in children: Sex-specific associations shown by brain diffusion tractography

BACKGROUND AND PURPOSE

Sleep quality is important for healthy growth and development of children. We aimed to identify associations between sleep disturbances in healthy children without clinical diagnosis of sleep disorders and brain white matter (WM) microstructure using an advanced diffusion-weighted magnetic resonance imaging (DW-MRI) based tractography analysis, and to explore whether there are sex differences in these associations.

METHODS

Brain DW-MRI data were collected from sixty-two 8-year-old children (28 boys, 34 girls) whose parents also completed Children's Sleep Habits Questionnaire (CSHQ). Track-weighted imaging (TWI) measures were computed from the DW-MRI data for 37 WM tracts in each subject. Sex-specific partial correlation analyses were performed to evaluate correlations between TWI measures and a set of sleep disturbance scores derived from the CSHQ.

RESULTS

Significant correlations (P < .05, FDR-corrected; r: .48-.67) were identified in 13 WM tracts between TWI and sleep disturbance scores. Sexually dimorphic differences in correlations between sleep disturbance scores and WM microstructure measurements were observed. Specifically, in boys, daytime sleepiness positively correlated with track-weighted mean or radial diffusivity in 10 WM tracts (bilateral arcuate fasciculus, left cingulum, right middle longitudinal fasciculus, and three bilateral segments of superior longitudinal fasciculus). In girls, total CSHQ score, night walking, or sleep onset delay negatively correlated with track-weighted fractional anisotropy or axial diffusivity in 4 WM tracts (bilateral inferior longitudinal fasciculus and uncinate fasciculus).

CONCLUSIONS

The findings suggest that sleep disturbances without clinical diagnosis of sleep disorders are associated with lower WM microstructural integrity in children. Additionally, the associations possess unique patterns in boys and girls.

Changes in objectively measured sleep among internationally adopted children in 1-year follow-up during the first years in new families

BACKGROUND

Psychosocial risks and environmental changes experienced by internationally adopted children may predict sleep problems, which are incidentally among the main concerns of adoptive parents. Several questionnaire studies have found sleep of internationally adopted children to be problematic, but none of those used an objective measure in a controlled study.

OBJECTIVE

To determine whether the objectively recorded sleep of internationally adopted children is worse than their controls who are living with their biological parents.

METHODS

To this case-control part of the Finnish Adoption Study, we recruited children who were adopted internationally to Finland between October 2012 and December 2016. Simultaneously, control children were recruited from 16 daycare centers. To assess sleep in children, actigraphy recordings were made twice, 1 year apart, between December 2013 and April 2018. In the adopted group, the first assessment took place 10 months after they had arrived in their families. The associations between adoption status and sleep parameters were analyzed using linear mixed modeling and adjusted for multiple potential confounders, including child age.

RESULTS

Seventy-eight internationally adopted children (boys 64%) aged 1-7 years and 99 controls (boys 53%) aged 2-6 years attended the first sleep recording. The recordings showed that the internationally adopted children slept longer (B = 0.48, 95% CI 0.23-0.73, P < 0.001) than the controls. There were no significant differences in sleep fragmentation or sleep efficiency between the groups. During the 1-year follow-up, the sleep patterns of the adopted children approached those of the controls.

CONCLUSIONS

The internationally adopted children spent more time in bed and slept more than their control children in both recordings. However, their sleep patterns were not very different from those of their peers and the differences appeared to vanish during the first years in their new family.

The association between sleep and empathy in young preschoolers: A population study

Sleep is vital for children's early socio-emotional development, particularly empathy. This study aimed to explore the associations between sleep and empathy in young preschoolers. A sample of 23,259 preschoolers (4.3 ± 0.3 years) at the entry year of preschool was recruited as part of the Shanghai Children's Health, Education and Lifestyle Evaluation-Preschool (SCHEDULE-P) study. Caregivers reported on child sleep, affective empathy, and cognitive empathy through the Children's Sleep Habits Questionnaire and the Griffith Empathy Measure. Ordinary least-square regression and quantile regression were performed for the associations between sleep and empathy. Sex differences were also investigated. Night sleep duration was negatively associated with affective empathy (β = -0.35, p < 0.001), and positively associated with cognitive empathy (β = 0.41, p < 0.001). Longer nap duration was associated with higher affective empathy (β = 0.28, p < 0.001). Sleep disturbances were positively associated with affective empathy (β = 0.04, p < 0.001) and negatively associated with cognitive empathy (β = -0.09, p < 0.001). These associations were generally stronger in children at higher empathy quantiles and also those at the 10^th cognitive empathy quantile. The associations between sleep and affective empathy were mainly contributed by girls, and were more common in boys in terms of cognitive empathy, particularly at the 10^th and the 30^th quantiles. In conclusion, longer night sleep duration and fewer sleep disturbances are associated with a more mature empathy pattern in young preschoolers. The associations are more prominent in children at the higher end of the empathy spectrum, and vary by sex. These findings highlight the importance to promote sleep health in young children for optimal socio-emotional development.

Presleep physiological stress is associated with a higher cortical arousal in sleep and more consolidated REM sleep

How sleep regulates physiological stress in healthy individuals is not well understood. We explored the associations between naturally occurring pre-sleep physiological arousal and EEG power spectral density together with rapid eye movement sleep (REMS) continuity. One hundred and fifty-four individuals (mean age 16.9, SD 0.1 years) collected five samples of saliva between the evening (mean time 18:20) and bedtime (mean 23:00) by using swabs, and underwent an overnight in-home polysomnography. We calculated spectral density for REMS and non-rapid eye movement sleep (non-REMS), and the number and duration of REMS arousals (<15 s) during sleep. An observational design allowed for measurement of natural variation in physiological and sleep arousal. Increasing cortisol levels toward bedtime were associated with higher EEG power spectral density at all frequency ranges in frontal locations, the highest association being for the beta1 frequency band. In central locations, the associations were pronounced for beta1 and beta2 bands. Higher overall cortisol levels in the evening were associated with less fragmented REMS. Presleep arousal was not associated with sleep staging. Physiological arousal toward bedtime was associated with EEG power spectral density values during sleep specifically at high EEG frequencies. This may represent a compensatory mechanism that serves as an adaptation to stress, since the REMS was more continuous along a higher physiological arousal level in the evening. Although causality cannot be inferred, a design with nonmanipulated physiological stress followed by naturally timed sleep at home provides new insights into stress regulation homeostasis.

Association Between Sleep Duration and Intelligence Quotient in 6-Year-Old Children

BACKGROUND

Sufficient sleep during childhood is important for cognitive functions such as learning and successful school performance. This study aimed to investigate the effects of sleep duration on the intelligence quotient (IQ) of 6-year-old children and aimed to analyze whether these effects differed by sex.

METHODS

The IQ of 538 6-year-old Korean participants from the cohort study, "The Environment and Development of Children," was measured during follow-up using the Korean Educational Developmental Institute's Wechsler Intelligence Scale for Children. The total, verbal, and performance IQ scores were evaluated. The relationship between sleep duration and IQ scores after adjusting for maternal age, maternal educational level, maternal occupation, maternal IQ, exposure to secondhand smoking, gestational age, and monthly age and birth season was also assessed.

RESULTS

Longer sleep duration was significantly associated with improved verbal IQ measures (β 0.55; p value 0.030). After stratifying participants by sex, a significant association was observed between sleep duration and total, verbal, and performance IQ scores in boys (total IQ 2.49, p value 0.012; verbal IQ 0.75, p value: 0.037; performance IQ 0.73, p value 0.048), but not in girls.

CONCLUSIONS

The results indicated that only boys show a significant association between IQ scores and sleep duration. These findings support the hypothesis that sleep duration is associated with IQ, in a sex dependent manner. Future studies are needed for a thorough evaluation of the connection between sleep duration and health outcome in young children.

Meta-analysis of age and actigraphy assessed sleep characteristics across the lifespan

STUDY OBJECTIVES

Sleep quantity and continuity vary across the lifespan. Actigraphy is a reliable and widely-used behavioral measure of sleep in research and personal health monitoring. This meta-analysis provides a novel examination of whether age (in years) is associated with actigraphy-assessed sleep across the lifespan.

METHODS

A systematic search of PubMed, Embase.com, Cochrane CENTRAL, and PsycINFO using "actigraphy" and "sleep" terms provided 7,079 titles/abstracts; studies of individuals with known psychiatric or medical comorbidities were excluded. Ninety-one articles (N = 23,365) provided data for six meta-analyses examining sleep duration (k = 89), sleep efficiency (k = 58), bedtime (k = 19) and waketime (k = 9) for individuals ages 6-21, and bedtime (k = 7) and waketime (k = 7) for individuals ages 22 and older.

RESULTS

At older ages, sleep duration was shorter (r = -0.12) and sleep efficiency was lower (r = -0.05). Older age was associated with later bedtime (r = 0.37) and wake-up time (r = 0.24) from ages 6-21, whereas older age was associated with earlier bedtime (r = -0.66) and wake-up time (r = -0.59) for ages 22 and above. The strength of these associations was modified by study continent, but not by any other moderator.

CONCLUSIONS

Age was negatively associated with actigraphy-assessed sleep duration and efficiency, but the effects were small in magnitude. On the other hand, large associations were observed between age and sleep timing, despite a smaller literature and the absence of analyzable data for ages 30-60. Changes in sleep timing, rather than changes in sleep duration or continuity, may better characterize the effects of age on human sleep.

Sleep disturbance and the long-term impact of early adversity

Sleep disturbance may be a central, yet underappreciated mechanism by which early adversity has a long-term impact upon mental and physical health. The fundamental regulatory processes shaped by early adversity - neural, neuroendocrine, and immune - are also central to sleep. Sleep problems, in turn, lead to a similar constellation of chronic health problems that have been linked to early adversity. We bring together work from the fields of early adversity and sleep in order to suggest a model by which sleep disturbance plays a critical role in the far-reaching impacts of early adversity on health. Future research should employ more longitudinal designs and pay particular attention to the impact of developmental periods such as adolescence and midlife when maturational and environmental factors conspire to create a unique time of sleep disturbance. We also suggesting that intervening to minimize sleep disturbance may be a promising means by which to test the model, as well as potentially blunt the long-term impact of early adversity on health.

Is moderate depression associated with sleep stage architecture in adolescence? Testing the stage type associations using network and transition probability approaches

BACKGROUND

Depression even at the subclinical level is often accompanied by sleep disturbances, but little is known about the dynamics of the sleep stages in relation to depressive symptoms. We examined whether the amount, associations, and transition probabilities of various sleep stages were associated with depressive symptoms in a community sample of adolescents.

METHODS

The participants (N = 172, 59% girls, mean age 16.9 years) underwent overnight polysomnography and provided data on depressive symptoms (Beck Depression Inventory II). The association between depression status and total duration of each stage type was analyzed using ANOVA and survival analyses. The associations between the number of different sleep stage types were analyzed using graphical Gaussian models, mixed graphical models, and relative importance networks. A Markov chain algorithm was used to estimate the transition probabilities between each state and these probabilities were further compared between depression status groups.

RESULTS

The associations between N1 and N3 were significantly stronger in both directions of the association (p-values for interactions 0.012 and 0.006) in those with more depressive symptoms. Similarly, a stronger association was observed from N1 to wake stage in those with more depressive symptoms (p-value for interaction 0.002). In those with more depressive symptoms, it was more likely to transition from N2 to N3 and from REM to N2 compared to others.

CONCLUSIONS

These findings indicate that changes in sleep architecture are not limited to clinical depression and that the transitional dynamics of sleep stages are an important marker of subclinical depression.

Persistent Short Sleep from Childhood to Adolescence: Child, Parent and Peer Predictors

PURPOSE

Many children have periods when they sleep too little, with widely recognized detrimental effects. Less is known about persistent short sleep during childhood. Therefore, the present study aimed to investigate the prevalence of persistent short sleep in school-aged children and identify a set of child, parent, and peer predictors thereof.

PARTICIPANTS AND METHODS

Objectively measured sleep duration (hip-held accelerometer) was biennially assessed in a community sample followed from 6 to 14 years (n=801). A latent profile analysis was applied to assess whether a subgroup of children slept consistently short across time and predictors of persistent short sleep were determined through regression analysis.

RESULTS

A subgroup of children (n=160; 20.2%) was identified as having persistent short sleep across time. Temperamental negative affectivity (β=0.08; 95% CI=0.01, 0.15; p=0.03) and low observer-assessed parental emotional availability (β=-.09; 95% CI=-.18, -.01; p=0.04) predicted membership to that group. Teacher ratings of victimization from bullying were not associated with persistent short sleep (β=0.01; 95% CI: -.10, 11; p=0.88).

CONCLUSION

High child temperamental negative affectivity and low parental emotional availability may be involved in the development of persistent short sleep through childhood.

The association between sleep-wake ratio and overnight picture recognition is moderated by BDNF genotype

A wealth of studies supports the role of sleep in memory performance. Experimentally controlled studies indicate that prolonged wake after memory encoding is detrimental for memory outcome whereas sleep protects from wake-time interference and promotes memory consolidation. We examined how the natural distribution of wake and sleep between encoding and retrieval associated with overnight picture recognition accuracy among 161 adolescents following their typical sleep schedule with an in-home polysomnography. The memorized pictures varied in their level of arousal (calm to exciting) and valence (negative to positive). Suspecting genotypic influence on the sensitivity for sleep/wake dynamics, we also assessed if these associations were affected by known gene polymorphisms involved in neural plasticity and sleep homeostasis: brain-derived neurotrophic factor (BDNF) Val66Met and Catechol-O-methyltransferase (COMT) Val158Met. In the whole sample, overnight recognition accuracy was associated with the levels of arousal and valence of the pictures, but not with sleep percentage (i.e. the percentage of time spent asleep between memory encoding and retrieval). While the allelic status of BDNF or COMT did not have any main effect on recognition accuracy, a significant moderation by BDNF Val66Met was found (p = .004): the subgroup homozygous for valine allele showed positive association between sleep percentage and recognition accuracy. This was underlain by detrimental influence of wake, rather than by any memory benefit of sleep. Our results complement the mounting evidence that the relation between sleep and memory performance is moderated by BDNF Val66Met. Further studies are needed to clarify the specific mechanisms.

Association of gender, oral habits, and poor sleep quality with possible sleep bruxism in schoolchildren

The aim of this study was to verify the oral habits, symptoms, and characteristics of some children aged 8 to 10 years that could be associated with possible sleep bruxism. A cross-sectional study was performed. Questionnaires were sent to parents to obtain information on sex, age, school shift, sleep quality, parents' perception of children's behavior, and children's oral habits (nail biting, object biting, and lip biting), and symptoms such as headache or earache. In addition, parents reported the frequency of sleep bruxism (no day to 7 days a week). Descriptive analysis and multinomial logistic regression were performed and the level of significance was set at 5%. A total of 1,554 parents of children aged 8 to 10 years participated in this study. Possible sleep bruxism was reported as mild for 65.7%, moderate for 25.3%, and severe for 9% of the children. In the adjusted multinomial logistic regression, boys were 79% more likely to have sleep bruxism (OR: 1.79; 95%CI 1.23-2.60) and were 2.06 more times at risk of being in the habit of lip biting (OR: 2.06; 95%CI 1.26-3.37). Children with possible severe sleep bruxism were 61% more likely to develop object biting (OR: 1.61; 95%CI 1.09-2.39), 52% more likely to have headaches (OR: 1.52; 95%CI 1.01-2.28), and 3.29 more times at risk of poor sleep quality (OR: 3.29; 95%CI 2.25-4.82). Based on the report, boys with lip and object biting habits, headaches, and poor sleep quality presented a higher chance of possible severe sleep bruxism.

Polygenic impact of morningness on the overnight dynamics of sleep spindle amplitude

Sleep spindles are thalamocortical oscillations that contribute to sleep maintenance and sleep-related brain plasticity. The current study is an explorative study of the circadian dynamics of sleep spindles in relation to a polygenic score (PGS) for circadian preference towards morningness. The participants represent the 17-year follow-up of a birth cohort having both genome-wide data and an ambulatory sleep electroencephalography measurement available ( N = 154, Mean age = 16.9, SD = 0.1 years, 57% girls). Based on a recent genome-wide association study, we calculated a PGS for circadian preference towards morningness across the whole genome, including 354 single-nucleotide polymorphisms. Stage 2 slow (9-12.5 Hz, N = 186 739) and fast (12.5-16 Hz, N = 135 504) sleep spindles were detected using an automated algorithm with individual time tags and amplitudes for each spindle. There was a significant interaction of PGS for morningness and timing of sleep spindles across the night. These growth curve models showed a curvilinear trajectory of spindle amplitudes: those with a higher PGS for morningness showed higher slow spindle amplitudes in frontal derivations, and a faster dissipation of spindle amplitude in central derivations. Overall, the findings provide new evidence on how individual sleep spindle trajectories are influenced by genetic factors associated with circadian type. The finding may lead to new hypotheses on the associations previously observed between circadian types, psychiatric problems and spindle activity.

Decreased need for sleep as an endophenotype of bipolar disorder: an actigraphy study

Reports of subjective sleep impairments have been replicated in adults with bipolar disorder (BD), young BD patients, and even children of parents with BD. Furthermore, circadian rhythm alterations are a core feature of BD. Despite the impairment in circadian rhythms and altered sleep included in various heuristic developmental models of BD, thus far, biomarkers have not been sufficiently objectively validated. Thus, here, we assessed the rest-activity circadian rhythmicity and sleep macrostructure using actigraphy in a sample of unaffected child and adolescent offspring of bipolar parents (BO; n = 43; 21 females; 11.0 ± 3.2 years) and controls (n = 42; 17 females; 11.1 ± 3.4 years) comparable in sex (p = .4) and age (p = .7). All participants wore a MotionWatch 8 (Camntech, Cambridge, UK) actigraph on their nondominant wrist for ≥ 14 days and completed sleep diaries. Psychopathology was assessed by the Kiddie Schedule for Affective Disorders and Schizophrenia and by subjective scales. The main areas of interest were rest-activity circadian rhythmicity, chronotype and sleep macrostructure. Subgroup analyses (child and adolescent subgroups) were conducted to identify physiological differences in sleep between these age groups. The BO and controls did not differ in the presence of current mood (p = .5) and anxiety (p = .6) disorders. The BO had shorter sleep time on free days (p = .007; effect size, Cohen´s d = 0.56), lower sleep efficiency on free days (p = .01; d = 0.47), lower prolongation of time in bed on free days (p = .046; d = 0.41), and lower social jet lag (p = .04; d = 0.5) than the controls. A longer sleep time on school days (p < .001; d = 0.21), lower prolongation of sleep time between school and free days (p = .008; d = 0.74), and larger difference in sleep onset latency between school days and free days (p = .009; d = 0.52) were observed in the adolescent BO than in the controls. The child BO had poorer sleep quality on free days than the controls (p = .02; d = 0.96). In all cases, the results remained significant after controlling for subthreshold mood and anxiety symptoms. The BO had less variable rest-activity rhythm than controls (p = .04; d = 0.32). No other significant differences between the BO and controls were observed in the rest-activity circadian rhythmicity and chronotype. The results showed decreased physiological catch-up sleep on free days in the BO, which may indicate a decreased need for sleep in this population. Thus, the decreased need for sleep observed in the unaffected BO may represent an endophenotype of BD.

Short sleep duration is associated with specific food intake increase among school-aged children in China: a national cross-sectional study

Background

The relationship between sleep duration and food intake is unclear. This study aims to examine the relationship among children aged 6–17 years in China.

Methods

The sample consisted of 70,519 children aged 6–17 years, which were randomly selected from 7 representative areas from China, from September to November, 2013. In the structured questionnaire, children reported daily sleep hours (less than 7 h, 7–9 h and more than 9 h), weekly food intake amount (including vegetables, fruit, sugar beverages and meat), physical activity and sedentary time. The relationship of sleep duration with vegetable, sugar beverage, fruit and meat intake was evaluated by multi-nominal logistic regression and multi-variable adjusted.

Results

A total of 62,517 children (51.6% boys) completed the study. Short sleep duration (SSD, < 7 h) was independently associated with increased sugar beverage intake (SBI, Odd Ratio, OR: 1.29, 95% CI: 1.19–1.40) but decreased vegetable (VI, OR: 0.94, 95% CI: 0.90–0.98) & fruit intake (FI, OR: 0.94, 95% CI: 0.88–0.99). Stratified by age and gender, SSD increased SBI for boys of both young (6–12 years) & older (13–17 years) groups and older girls (ORs: 1.25, 1.25, 1.49, 95% CI: 1.08–1.44, 1.04–1.50, 1.22–1.81, respectively), but decreased VI and FI for older girls (ORs: 0.84& 0.81, 95% CI: 0.74–0.96& 0.68–0.96, respectively).

Conclusions

Among school-aged children in China, short sleep duration was associated with increased risks of more sugar beverage intake among those younger and boys but less vegetable & fruit intake among those older and girls. Longitudinal research is needed to clarify the causation in between.

A Qualitative Study of How Preschoolers' Problematic Sleep Impacts Mothers

BACKGROUND

Sleep disturbances are common among preschool-aged children. As children's problematic sleep is commonly defined by subjective reports from parents as to how the issue affects them, we took a qualitative approach to explore the perceptions and experiences of mothers and main caregivers of preschoolers with problematic sleep. The aim was to understand their firsthand experiences.

METHODS

Purposive sampling was used to identify mothers of 3- to 4-year-olds whose sleep was a problem for them. Semistructured interviews were conducted with 16 mothers. The interviews were analyzed for anticipated and emergent themes, the latter generated from exploring the impact of the child's sleep problems on the mother herself.

RESULTS

Mothers described difficulties mainly with bedtime resistance and night waking and the adverse consequences affecting siblings and partners. Predominant themes falling under the umbrella of emotional responses (e.g., resignation, guilt or shame, confusion or frustration, and defeat) and daytime functioning (e.g., exhaustion, moodiness, poorer concentration, less socializing) emerged from mothers describing the impact the child's sleep problem had on her personally.

CONCLUSIONS

This study highlights the overwhelming impact a child's sleep problems can have on a mother both emotionally and physically, and expressions of shame and guilt suggest some mothers assume much of the responsibility for their child's sleep problem. The findings provide insight into understanding mothers' personal responses in dealing with their preschoolers' sleep that could be useful to assist health professionals in history taking and establishing a treatment plan.

Developmental trends in sleep during adolescents' transition to young adulthood

OBJECTIVE

Poor sleep poses negative health consequences for youth, yet few longitudinal actigraphy studies have examined basic developmental trends in sleep across adolescents' transition to young adulthood. In this longitudinal actigraphy study, stability of individual differences and trajectories of sleep during and after high school were examined. The degree to which sleep trajectories differed by college attendance status was also studied.

METHODS

A total of 343 youth with Asian, Latino, and European American backgrounds completed eight days of wrist actigraphy at two-year intervals in Wave 1 (n = 295, M_age = 16.39), Wave 2 (n = 211 including 34 new participants to refresh the sample, M_age = 18.31), and Wave 3 (n = 144, M_age = 20.29). Sleep duration, efficiency, and latency were estimated for weekdays and weekends. Intra-individual variability in duration across nights was also obtained.

RESULTS

Sleep parameters were correlated modestly between Wave 1 and Wave 2, but not correlated between Wave 1 and Wave 3, indicating modest shorter-term and little longer-term stability of individual differences. Multilevel growth models demonstrated declines in weekday sleep duration and efficiency across high school and post-high school years. Intra-individual variability in duration increased over the years. Latency trajectories changed more for non-college attendees compared with college attendees.

CONCLUSIONS

Overall the findings suggest developmental trends of worsening sleep during adolescents' transition to young adulthood. Interventions to improve sleep may need to target specific issues faced by youth at that particular period in their lives.

Autistic Traits Are Associated With Decreased Activity of Fast Sleep Spindles During Adolescence

STUDY OBJECTIVES

Autistic traits present a continuum from mild symptoms to severe disorder and have been associated with a high prevalence of sleep problems. Sleep spindles have a key function in sleep maintenance and in brain plasticity. Previous studies have found decreased spindle activity in clinical autism. Here we examine the associations between the entire range of autistic traits and sleep spindle activity in a nonclinical community cohort of adolescents.

METHODS

Our cohort is based on 172 adolescents born in 1998 (58.7% girls, mean age = 16.9 years, standard deviation = 0.1), who filled in the adult autism-spectrum quotient (AQ), consisting of total score, and social interaction and attention to details subscales. Participants underwent an ambulatory overnight sleep electroencephalography. Sleep spindles (amplitude, duration, density, and intensity) were automatically detected from stage N2 sleep, and divided to slow and fast spindles.

RESULTS

Higher AQ total sum and social interaction sum associated with lower fast spindle amplitude and intensity (P < .04). No associations were observed for attention to details.

CONCLUSIONS

Our findings indicate that a higher level of autistic traits in the nonclinical range among generally healthy adolescents associate with similar alterations in sleep spindle activity as observed in many neuropsychiatric conditions, indicating lower sleep-related brain plasticity. This indicates that sleep microstructures form a continuum that follows self-reported symptoms of autism.

REM sleep fragmentation associated with depressive symptoms and genetic risk for depression in a community-based sample of adolescents

INTRODUCTION

Fragmented REM sleep may impede overnight resolution of distress and increase depressive symptoms. Furthermore, both fragmented REM and depressive symptoms may share a common genetic factor. We explored the associations between REM sleep fragmentation, depressive symptoms, and a polygenic risk score (PRS) for depression among adolescents.

METHODS

About 161 adolescents (mean age 16.9 ± 0.1 years) from a birth cohort underwent a sleep EEG and completed the Beck Depression Inventory-II the same day. We calculated PRSes for depressive symptoms with PRSice 1.25 software using weights from a recent genome-wide association study for dimensions of depressive symptoms (negative emotion, lack of positive emotion and somatic complaints). REM fragmentation in relation to entire REM duration was manually calculated from all REM epochs. REM latency and density were derived using SomnoMedics DOMINO software.

RESULTS

PRSes for somatic complaints and lack of positive emotions were associated with higher REM fragmentation percent. A higher level of depressive symptoms was associated with increased percent of REM fragmentation and higher REM density, independently of the genetic risks. Belonging to the highest decile in depressive symptoms was associated with a 2.9- and 7.6-fold risk of belonging to the highest tertile in REM fragmentation and density. In addition, higher PRS for somatic complaints had an independent, additive effect on increased REM fragmentation.

LIMITATION

A single night's sleep EEG was measured, thus the night-to-night stability of the REM fragmentation-depressive symptom link is unclear.

CONCLUSION

Depressive symptoms and genetic risk score for somatic complaints are independently associated with more fragmented REM sleep. This offers new insights on the quality of sleep and its relation to adolescents' mood.

Cerebellar Gray Matter Volume, Executive Function, and Insomnia: Gender Differences in Adolescents

The cerebellum is an important region responsible for adolescent cognitive function and sleep, and their correlation is expected to show different patterns depending on age and gender. We examined the regional cerebellar gray matter volume (GMV), executive function (EF) and insomnia symptoms to identify their correlation and gender differences in adolescents. Data for a total of 55 subjects' (M = 31, F = 24, 14.80 ± 1.39 years old) were analyzed. The correlations between cerebellar regional GMV and Wisconsin card sorting test (WCST) subcategories showed that EF was better with larger GMV both in males and females. Far more overall correlations with cerebellar regions were observed in boys, with corresponding correlation strength being higher, and differences in localization were also observed in contrast to girls. Larger cerebellar GMV corresponded to better EF in adolescents. Insomnia did not influence the correlations between cerebellar regional GMV and EF, but more severe insomnia in boys correlated to smaller GMV in the right flocculonodular lobe. These results might implicate that the adolescent cerebellum is involved differently in EF dependent on gender.

Higher sleep spindle activity is associated with fewer false memories in adolescent girls

BACKGROUND

Sleep facilitates the extraction of semantic regularities amongst newly encoded memories, which may also lead to increased false memories. We investigated sleep stage proportions and sleep spindles in the recollection of adolescents' false memories, and their potential sex-specific differences.

METHODS

196 adolescents (mean age 16.9 y; SD = 0.1, 61% girls) underwent the Deese, Roediger & McDermott (DRM) false memory procedure and overnight polysomnography, with free recall the following morning. Sleep was scored manually into stages 1, 2, 3 and REM. Stage 2 sleep spindle frequency, density, and peak amplitude were used as measures of spindle activity for slow (10-13 Hz) and fast (13-16 Hz) ranges.

RESULTS

In girls, a lower number of critical lures was associated with higher spindle frequency (p ≤ 0.01), density (p ≤ 0.01), and amplitude (p = 0.03). Additionally, girls' longer sleep duration was associated with more intrusion words (p = 0.03), but not with critical lures. These associations survived adjustment for age, pubertal status, and intelligence. No significant results emerged in boys.

CONCLUSIONS

In adolescent girls, higher spindle activity was associated with fewer critical lures being falsely recalled in the DRM paradigm. Unlike studies using adult participants, we did not observe any association between slow-wave sleep and false memory recollection.

Prenatal and early life origins of adolescence sleep problems: evidence from a birth cohort

PURPOSE

This study aims to identify the prenatal and early life predictors of adolescence sleep problems.

METHODS

Sleep data (n = 5081) from the 14-year (13.92 ± 0.34 years) follow-up of a birth cohort were analyzed to explore the predictors of adolescence trouble sleeping, nightmares, snoring and sleep talking/walking. Data from the antenatal period till adolescence were explored for identifying predictors of adolescence sleep problems. Modified Poisson regression with a robust error variance was used to identify significant predictors.

RESULTS

Our results suggest that about a quarter of adolescents in our study sample had sleep maintenance problems (nightmares: 27.88%, snoring: 23.20%, sleepwalking/talking 27.72%). The prevalence rate of sleep initiation problems was even higher (trouble sleeping: 40.61%). Our results suggest that antenatal and early-life factors, e.g. maternal smoking, anxiety, sleep problems in childhood, attention deficit hyperactivity disorder (ADHD) symptoms, and poor health are significant predictors of adolescence sleep problems.

CONCLUSIONS

This study demonstrates the predictive role of prenatal and early life risk factors in adolescence sleep problems. It seems that exposure to prenatal and early life risk factors increase the vulnerability for sleep problems later in life, which is further supported by poor health and lifestyle choices in adolescence. Therefore, close observation and mitigation of factors associated with early life risk factors could be a potential strategy for preventing sleep problems later in life.

Sleeping habits of adolescents in relation to their physical activity and exercise output: results from the ELSPAC study

BACKGROUND

Little is known about the effects of physical activity and fitness on sleep timing parameters in adolescence.

METHODS

We investigated the development of sleep timing between age 8 and 15 and its association with physical fitness at age 15 in 787 adolescents (408 males, 379 females). Physical fitness was measured using the physical work capacity (PWC) protocol. Information on sport activity was collected at ages 11 and 15. Finally, the contribution of other covariates (sex, body mass index (BMI), parental education and occupational skill level) to the association between sleep parameters and physical fitness was evaluated. The correlation of BMI and physical fitness was assessed separately.

RESULTS

Mild correlation of sleep duration at ages 8 and 15 was observed (r=0.08-0.16). Higher sport activity participation and physical fitness were found to be mildly associated with delayed bedtime and reduced sleep duration; the association with bedtime was significant after adjustment for all covariates. Sport activity at age 11 was not associated with sleep timing at age 15. Interestingly, higher BMI was linked to delayed bedtime and higher physical fitness.

CONCLUSION

Our findings do not support existing hypotheses suggesting the association of low physical activity and fitness with shorter sleep duration and high BMI in a generally non-obese adolescent population without severe sleep restriction.

Correspondence of maternal and paternal perception of school-aged children's sleep with in-home sleep-electroencephalography and diary-reports of children's sleep

OBJECTIVE

Parents are often the first to report children's sleep difficulties. The aim of the present study was to evaluate the accuracy of parent reports by examining the correspondence of maternal and paternal reports of children's sleep with in-home electroencephalography (EEG) sleep assessment and sleep diary reports.

METHODS

A total of 143 children (57 formerly very preterm born children) aged 7-12 years underwent one night of in-home sleep-EEG; mothers and fathers reported children's sleep-related behavior by using the German version of the Children's Sleep Habits Questionnaire, and children and parents together completed a sleep diary of children's sleep.

RESULTS

Less EEG-derived total sleep time (TST) was associated with increased mother questionnaire reports of sleep duration problems, while less sleep efficiency (SE) and longer sleep onset latency (SOL) were associated with increased mother questionnaire reports of sleep onset delay. For fathers, only longer SOL was related to increased father questionnaire reports of sleep onset delay. The abovementioned associations did not change with children's increasing age and did not differ for boys and girls. More parent questionnaire reports of sleep duration problems, sleep onset delay, and night wakings were related to shorter diary reports of sleep duration, increased sleep latency, and more nocturnal awakenings, respectively.

CONCLUSIONS

Mother questionnaire reports of children's sleep corresponded moderately with objective measures of TST, SE, and SOL assessed with in-home sleep-EEG. Both mother and father questionnaire reports of children's sleep duration problems, sleep onset delay, and night wakings were related to diary reports of children's sleep.

Schizotypal traits are associated with sleep spindles and rapid eye movement in adolescence

Research suggests an association between schizophrenia and a decrease in sleep spindle activity, as well as a change in sleep architecture. It is unknown how the continuum of psychotic symptoms relates to different features in the sleep electroencephalogram. We set out to examine how sleep architecture and stage 2 spindle activity are associated with schizotypy in a healthy adolescent population. The participants in our study (n = 176, 61% girls) came from a community-based cohort. Schizotypal traits were evaluated using the Schizotypal Personality Scale (STA) in early adolescence (mean age 12.3 years, SD = 0.5) and the participants underwent ambulatory overnight polysomnography at mean age 16.9 years (SD = 0.1). Sleep was scored in 30-s epochs into stages 1, 2, 3 and rapid eye movement (REM) sleep. Stage 2 spindles were detected using an automated algorithm. Spindle analyses from central and frontal derivations included spindle duration and density for slow (10-13 Hz) and fast (13-16 Hz) ranges. Covariates included sex and age. Those with the highest STA scores had a higher percentage of REM (B = 2.07 [95% CI, 0.17, 4.0]; p = .03) than those with the lowest scores. Those with the highest scores had shorter spindle duration, as derived from the frontal regions, and a slower oscillation range (B = -0.04 [95% CI, -0.07, -0.01]; p = .023) than those with the lowest scores. We conclude that high levels of schizotypy characteristics measured in early adolescence may be associated with distinguished features of sleep architecture, namely with spindle morphology and a higher proportion of REM sleep.

Development of Late Circadian Preference: Sleep Timing From Childhood to Late Adolescence

OBJECTIVES

To assess differences relating to circadian preference in objectively measured sleep patterns from childhood to adolescence over a 9-year period. We hypothesized there is developmental continuity in sleep timing and duration according to circadian preference.

STUDY DESIGN

Young participants (N = 111, 65% girls) from a community-based birth cohort underwent sleep actigraphy at mean ages 8.1 (SD = 0.3), 12.3 (SD = 0.5), and 16.9 (SD = 0.1) years. A short version of Morningness-Eveningness Questionnaire was administered in late adolescence. At each follow-up, sleep midpoint, duration, wake after sleep onset, sleep efficiency, and weekend catch-up sleep were compared between those reporting morning, intermediate, and evening preferences in late adolescence.

RESULTS

Mixed model analyses indicated that sleep timing was significantly earlier among morning types compared with evening types at all ages (P values < .04). The mean differences in sleep midpoint between morning and evening types increased from a mean of 19 minutes (age 8), 36 minutes (age 12), to 89 minutes (age 17). The largest change occurred from age 12 to 17 years. Sleep duration, wake after sleep onset, sleep efficiency, and catch-up sleep did not differ according to circadian preference.

CONCLUSIONS

This study found significant continuity in sleep timing from childhood to adolescence over 9 years, indicating that late circadian preference reported in late adolescence begins to manifest in middle childhood. Further studies are needed to establish whether sleep timing has its origins at an even earlier age.

The Association Between Anxiety Symptoms and Sleep in School-Aged Children: A Combined Insight From the Children's Sleep Habits Questionnaire and Actigraphy

The current study assessed the association between anxiety symptoms and sleep in 90 school-aged children, aged 6-12 years (M_age = 108 months, 52.2% male). The Children's Sleep Habits Questionnaire (CSHQ) and 14 nights of actigraphy were used to assess sleep. Anxiety was assessed using the Spence Children's Anxiety Scale (SCAS). A significant association was found between parent-reported anxiety symptoms and current sleep problems (i.e., CSHQ total scores ≥ 41). An examination of SCAS subscales identified a specific association between generalized anxiety disorder (GAD) symptoms and increased parental sleep concerns, including sleep onset delay, sleep duration, and daytime sleepiness. Regarding actigraphy, whilst anxiety was not associated with average sleep variables, a relationship was identified between anxiety and the night-to-night variability of actigraphy-derived sleep schedules.

Circadian preference towards morningness is associated with lower slow sleep spindle amplitude and intensity in adolescents

Individual circadian preference types and sleep EEG patterns related to spindle characteristics, have both been associated with similar cognitive and mental health phenotypes. However, no previous study has examined whether sleep spindles would differ by circadian preference. Here, we explore if spindle amplitude, density, duration or intensity differ by circadian preference and whether these associations are moderated by spindle location, frequency, and time distribution across the night. The participants (N = 170, 59% girls; mean age = 16.9, SD = 0.1 years) filled in the shortened 6-item Horne-Östberg Morningness-Eveningness Questionnaire. We performed an overnight sleep EEG at the homes of the participants. In linear mixed model analyses, we found statistically significant lower spindle amplitude and intensity in the morning as compared to intermediate (P < 0.001) and evening preference groups (P < 0.01; P > 0.06 for spindle duration and density). Spindle frequency moderated the associations (P < 0.003 for slow (<13 Hz); P > 0.2 for fast (>13 Hz)). Growth curve analyses revealed a distinct time distribution of spindles across the night by the circadian preference: both spindle amplitude and intensity decreased more towards morning in the morning preference group than in other groups. Our results indicate that circadian preference is not only affecting the sleep timing, but also associates with sleep microstructure regarding sleep spindle phenotypes.

Mother-father agreement and one-year stability of children's sleep functioning

OBJECTIVES

To (1) evaluate mother-father agreement of total sleep problems and specific sleep problem domains and (2) examine the one-year stability of children's sleep functioning, including cross-rater stability.

METHODS

A community-based sample of 519 children (51% boys) in Spain was assessed in third grade and again 1 year later. At each time-point, both mothers and fathers provided ratings of sleep functioning using the Children's Sleep Habits Questionnaire (CSHQ).

RESULTS

Sleep scores did not differ between mothers' and fathers' ratings. Cross-sectionally (at both time-points) and longitudinally (from grade 3 to grade 4), strong agreement was found between mothers' and fathers' ratings of total sleep problems, sleep habits, night wakings, and parasomnias. Lower agreement was found for daytime sleepiness and sleep onset delay. There was large effect size stability for both mothers' and fathers' ratings over the one-year period on the total sleep disturbance scale and most sleep subscales.

CONCLUSIONS

This study provides the first evidence of strong mother-father agreement on subjective ratings of children's sleep functioning, both concurrently and over a one-year period, for overall sleep problems and certain sleep domains. However, agreement was far from identical, and further studies are needed to evaluate reasons for discrepancy and whether mother-father discrepancy in sleep functioning predicts children's functioning. More studies are needed that systematically include both mothers' and fathers' perspectives regarding children's sleep.