How long does the average person sleep? Here, Kocevska et al. conducted a meta-analysis including over 1.1 million people to produce age- and sex-specific population reference charts for sleep... Show moreHow long does the average person sleep? Here, Kocevska et al. conducted a meta-analysis including over 1.1 million people to produce age- and sex-specific population reference charts for sleep duration and efficiency.We aimed to obtain reliable reference charts for sleep duration, estimate the prevalence of sleep complaints across the lifespan and identify risk indicators of poor sleep. Studies were identified through systematic literature search in Embase, Medline and Web of Science (9 August 2019) and through personal contacts. Eligible studies had to be published between 2000 and 2017 with data on sleep assessed with questionnaires including >= 100 participants from the general population. We assembled individual participant data from 200,358 people (aged 1-100 years, 55% female) from 36 studies from the Netherlands, 471,759 people (40-69 years, 55.5% female) from the United Kingdom and 409,617 people (>= 18 years, 55.8% female) from the United States. One in four people slept less than age-specific recommendations, but only 5.8% slept outside of the 'acceptable' sleep duration. Among teenagers, 51.5% reported total sleep times (TST) of less than the recommended 8-10 h and 18% report daytime sleepiness. In adults (>= 18 years), poor sleep quality (13.3%) and insomnia symptoms (9.6-19.4%) were more prevalent than short sleep duration (6.5% with TST < 6 h). Insomnia symptoms were most frequent in people spending >= 9 h in bed, whereas poor sleep quality was more frequent in those spending <6 h in bed. TST was similar across countries, but insomnia symptoms were 1.5-2.9 times higher in the United States. Women (>= 41 years) reported sleeping shorter times or slightly less efficiently than men, whereas with actigraphy they were estimated to sleep longer and more efficiently than man. This study provides age- and sex-specific population reference charts for sleep duration and efficiency which can help guide personalized advice on sleep length and preventive practices. Show less
Adrichem, D.S. van; Huijbregts, S.C.J.; Heijden, K.B. van der; Goozen, S.H.M. van; Swaab, H. 2020
Impaired empathy has been associated with aggression in children, adolescents and adults, but results have been contradictory for the preschool period. Impaired inhibitory control also increases... Show moreImpaired empathy has been associated with aggression in children, adolescents and adults, but results have been contradictory for the preschool period. Impaired inhibitory control also increases the risk of aggression, and possibly moderates empathy-aggression associations. The current study investigated whether empathy and inhibitory control are associated with aggression in toddlerhood. Furthermore, we aimed to clarify the role of inhibitory control in empathy and aggression, specifically, whether inhibitory control moderates the association between empathy and aggression. During a laboratory visit at age 30 months (N = 103), maternal reports of physical aggression were obtained and child inhibitory control was examined using a gift delay task. Empathy was examined by obtaining behavioral observations and recording physiological responses (heart rate response and respiratory sinus arrhythmia response) to an empathy-eliciting event (i.e., simulated distress). Reduced inhibitory control was associated with more aggression. Behavioral and physiological indicators of empathy were not associated with aggression. Hierarchical regression analyses revealed an interaction effect of heart rate response to distress simulation with inhibitory control in the prediction of aggression. Post hoc analyses indicated a negative association between heart rate response and aggression when inhibitory control was high, but a positive association was found in toddlers who demonstrated low inhibitory control. These results suggest that children are less aggressive when they have both high levels of empathy and inhibitory control. Therefore, both empathy and inhibition are important targets for interventions aiming to reduce or prevent aggression at a young age. Show less
Adrichem, D.S. van; Huijbregts, S.C.J.; Heijden, K.B. van der; Goozen, S.H.M. van; Swaab, H. 2019
Parental beliefs, parenting behavior, and precursors of theory of mind have been related uniquely to each other and to early aggression, but have not yet been studied simultaneously. The present... Show moreParental beliefs, parenting behavior, and precursors of theory of mind have been related uniquely to each other and to early aggression, but have not yet been studied simultaneously. The present study combined these risk factors in the prediction of aggression during toddlerhood using a sample of 152 mother-child dyads. At 20 months, mothers' parental beliefs (parental self-efficacy and perceived parental impact) were examined with the Parental Cognitions and Conduct Toward the Infant Scale. Maternal parenting behavior (sensitivity, intrusiveness, and successful positive engagement) was observed during free play and teaching tasks, and children's precursors of theory of mind were assessed using a visual perspectives task and an imitation task. At 30 months, child aggression was examined using the Child Behavior Checklist. A regression analysis indicated that lower parental self-efficacy and lower imitation skills predicted more aggressive behavior. When estimating the indirect effects using bootstrapping, a final model was found indicating that lower perceived parental impact was related to less successful positive engagement, which, in turn, was associated with children's poorer imitation abilities which predicted more aggressive behavior. It can be concluded that aggression during toddlerhood is predicted significantly by interrelated parental beliefs, parenting behavior, and children's early social cognitive abilities. Show less
Noten, M.M.P.G.; Heijden, K.B. van der; Huijbregts, S.C.J.; Goozen, S.H.M. van; Swaab, H. 2019
Although emotional responses are theorized to be important in the development of empathy, findings regarding the prediction of early empathic behavior by infant behavioral and physiological... Show moreAlthough emotional responses are theorized to be important in the development of empathy, findings regarding the prediction of early empathic behavior by infant behavioral and physiological responses are mixed. This study examined whether behavioral and physiological responses to mild emotional challenge (still face paradigm and car seat task) in 118 infants at age 6 months predicted empathic distress and empathic concern in response to an empathy-evoking task (i.e, experimenter's distress simulation) at age 20 months. Correlation analyses, corrected for sex and baseline levels of physiological arousal, showed that stronger physiological and behavioral responses to emotional challenge at age 6 months were positively related to observed empathic distress, but not empathic concern, at age 20 months. Linear regression analyses indicated that physiological and behavioral responses to challenge at 6 months independently predicted empathic distress at 20 months, which suggests an important role for both physiological and behavioral emotional responses in empathy development. In addition, curvilinear regression analyses showed quadratic associations between behavioral responses at 6 months, and empathic distress and empathic concern at 20 months, which indicates that moderate levels of behavioral responsivity predict the highest levels of empathic distress and empathic concern. Show less
Adrichem, D.S. van; Huijbregts, S.C.J.; Heijden, K.B. van der; Goozen, S.H.M. van; Swaab, H. 2019
Prenatal risk and a lack of inhibitory control have consistently been related to the development of physical aggression in older children. This study examined whether inhibitory control mediated... Show morePrenatal risk and a lack of inhibitory control have consistently been related to the development of physical aggression in older children. This study examined whether inhibitory control mediated the relation between prenatal risk and aggression in infants and toddlers. The role of gender in this mediation model was also examined. The sample consisted of 161 mother-child dyads (83 boys). A prenatal cumulative risk score was created from a number of well-established risk factors including maternal psychopathology, substance use, and social and socioeconomic disadvantages. At 12 months, children performed an inhibitory control task. Physical aggression was assessed through maternal reports at 12 and 20 months of age. Results showed that higher prenatal risk was associated with more physical aggression. Inhibitory control mediated this association at both 12 and 20 months: higher prenatal risk was related to lower inhibitory control, which in turn led to higher aggression. At 20 months, gender moderated the mediation effect: the mediating role of inhibitory control was only found for girls. These results suggest that even before 2 years of age, inhibitory control is an important construct involved in the relation between prenatal risk and physical aggression. Show less
Noten, M.M.P.G.; Heijden, K.B. van der; Huijbregts, S.C.J.; Goozen, S.H.M. van; Swaab, H. 2019
Research indicates that impaired empathy is a risk factor of aggression and that social attention is important for empathy. The role of social attention in associations between empathy and... Show moreResearch indicates that impaired empathy is a risk factor of aggression and that social attention is important for empathy. The role of social attention in associations between empathy and aggression has not yet been fully elucidated. Therefore, indicators of affective empathy, cognitive empathy, social attention, and aggression were simultaneously assessed in children aged 45 months. A total of 61 mother-child dyads participated in a lab visit, during which maternal reports of aggression were obtained. Children watched three clips showing a sad, scared, and happy child, respectively, and a neutral social clip while heart rate was recorded. Heart rate change from nonsocial baseline clips to emotional clips was calculated as an index of affective empathy. Questions about the emotions of the children in the clips were asked to assess cognitive empathy. Social attention was defined as time spent looking at faces during the clips. Correlation analyses revealed negative associations between affective empathy and aggression and between social attention and aggression. Furthermore, multivariate linear regression analyses indicated that the association between affective empathy and aggression was moderated by social attention; the negative association between affective empathy and aggression was stronger in children with relatively reduced social attention. No association was found between cognitive empathy and aggression. Therefore, both affective empathy and social attention are important targets for early interventions that aim to prevent or reduce aggression. (C) 2019 Elsevier Inc. All rights reserved. Show less
Vermeulen, M.C.M.; Heijden, K.B. van der; Swaab, H.; Someren, E.J.W. van 2019
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... Show moreThe 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. Show less
Sleep problems are highly prevalent in ADHD and autism spectrum disorder (ASD). Better insight in the etiology is of clinical importance since intervention and prevention strategies of sleep... Show moreSleep problems are highly prevalent in ADHD and autism spectrum disorder (ASD). Better insight in the etiology is of clinical importance since intervention and prevention strategies of sleep problems are directed at underlying mechanisms. We evaluated the association of sleep problems and sleep patterns with sleep hygiene (behavioral/environmental practices that influence sleep quality, e.g. caffeine use), access to electronic media, chronotype, and anxiety/depression in children aged 6–12 years with ADHD, ASD, or typical development (TD) using parental questionnaires. ANOVA and linear regression analyses were adjusted for age and sex. Children with ADHD and ASD showed more sleep problems (63.6 and 64.7%, vs 25.1% in TD) and shorter sleep duration than controls, while differences between ADHD and ASD were not significant. Sleep hygiene was worse in ADHD and ASD compared to TD, however, the association of worse sleep hygiene with more sleep problems was only significant in ASD and TD. There was a significant association of access to electronic media with sleep problems only in typically developing controls. Chronotype did not differ significantly between groups, but evening types were associated with sleep problems in ADHD and TD. Associations of greater anxiety/depression with more sleep problems were shown in ADHD and TD; however, anxiety/depression did not moderate the effects of chronotype and sleep hygiene. We conclude that sleep problems are highly prevalent in ADHD and ASD, but are differentially related to chronotype and sleep hygiene. In ASD, sleep problems are related to inadequate sleep hygiene and in ADHD to evening chronotype, while in TD both factors are important. Clinical implications are discussed. Show less
Heijden, K.B. van der; Vermeulen, M.C.M.; Donjacour, C.E.H.M.; Gordijn, M.C.M.; Hamburger, H.L.; Meijer, A.M.; ... ; Weysen, T. 2017
Inadequate sleep impairs cognitive function and has been associated with worse academic achievement in higher education students; however, studies that control for relevant background factors and... Show moreInadequate sleep impairs cognitive function and has been associated with worse academic achievement in higher education students; however, studies that control for relevant background factors and include knowledge on sleep hygiene are scarce. This study examined the association of chronic sleep reduction (i.e. symptoms of chronic sleep reduction such as shortness of sleep, sleepiness and irritation), subjective sleep quality and sleep hygiene knowledge with academic achievement (grades and study credits) and study concentration among 1378 higher education students (71% female, mean age 21.73 years, SD = 3.22) in the Netherlands. Demographic, health, lifestyle and study behaviour characteristics were included as covariates in hierarchical regression analyses. After controlling for significant covariates, only chronic sleep reduction remained a significant predictor of lower grades (last exam, average in current academic year). Better sleep quality and sleep hygiene knowledge were associated with better academic achievement, but significance was lost after controlling for covariates, except for a remaining positive association between sleep hygiene beliefs and grades in the current academic year. Moreover, better sleep quality and lower scores on chronic sleep reduction were associated with better study concentration after controlling for significant covariates. To conclude, chronic sleep reduction is associated with academic achievement and study concentration in higher education students. Inadequate sleep hygiene knowledge is moderately associated with worse academic achievement. Future research should investigate whether sleep hygiene interventions improve academic achievement in students of higher education. Show less
Suurland, J.; Heijden, K.B. van der; Smaling, H.J.A.; Huijbregts, S.C.J.; Goozen, S.H.M. van; Swaab, H. 2017
Exposure to prenatal adversity is associated with aggression later in life. Individual differences in autonomic nervous system (ANS) functioning, specifically nonreciprocal activation of the... Show moreExposure to prenatal adversity is associated with aggression later in life. Individual differences in autonomic nervous system (ANS) functioning, specifically nonreciprocal activation of the parasympathetic (PNS) and sympathetic (SNS) nervous systems, increase susceptibility to aggression, especially in the context of adversity. Previous work examining interactions between early adversity and ANS functioning in infancy is scarce and has not examined interaction between PNS and SNS. This study examined whether the PNS and SNS moderate the relation between cumulative prenatal risk and early physical aggression in 124 children (57% male). Cumulative risk (e.g., maternal psychiatric disorder, substance (ab)use, and social adversity) was assessed during pregnancy. Parasympathetic respiratory sinus arrhythmia (RSA) and sympathetic pre-ejection period (PEP) at baseline, in response to and during recovery from emotional challenge were measured at 6 months. Physical aggression and non-physical aggression/oppositional behavior were measured at 30 months. The results showed that cumulative prenatal risk predicted elevated physical aggression and non-physical aggression/oppositional behavior in toddlerhood; however, the effects on physical aggression were moderated by PNS and SNS functioning. Specifically, the effects of cumulative risk on physical aggression were particularly evident in children characterized by low baseline PNS activity and/or by nonreciprocal activity of the PNS and SNS, characterized by decreased activity (i.e., coinhibition) or increased activity (i.e., coactivation) of both systems at baseline and/or in response to emotional challenge. These findings extend our understanding of the interaction between perinatal risk and infant ANS functioning on developmental outcome. Show less
Suurland, J.; Heijden, K.B. van der; Huijbregts, S.C.J.; Goozen, S.H.M. van; Swaab, H. 2017
Nonreciprocal action of the parasympathetic (PNS) and sympathetic (SNS) nervous systems, increases susceptibility to emotional and behavioral problems in children exposed to adversity. Little is... Show moreNonreciprocal action of the parasympathetic (PNS) and sympathetic (SNS) nervous systems, increases susceptibility to emotional and behavioral problems in children exposed to adversity. Little is known about the PNS and SNS in interaction with early adversity during infancy. Yet this is when the physiological systems involved in emotion regulation are emerging and presumably most responsive to environmental influences. We examined whether parasympathetic respiratory sinus arrhythmia (RSA) and sympathetic pre-ejection period (PEP) response and recovery at six months, moderate the association between cumulative prenatal risk and physical aggression at 20 months (N = 113). Prenatal risk predicted physical aggression, but only in infants exhibiting coactivation of PNS and SNS (i.e., increase in RSA and decrease in PEP) in response to stress. These findings indicate that coactivation of the PNS and SNS in combination with prenatal risk is a biological marker for the development of aggression. Show less
Vermeulen, M.C.M.; Heijden, K.B. van der; Benjamins, J.S.; Swaab, H.; Van Someren, E.J.W. 2017
