Children differ in their school performances, which are influenced by their executive functions (EF). The cause of these differences can probably be explained by individual differences in sleep...Show moreChildren differ in their school performances, which are influenced by their executive functions (EF). The cause of these differences can probably be explained by individual differences in sleep duration and temperament. The moderating effect of temperament on the association between sleep duration and EF and mutual relations have been studied. The sample consisted of 499 ‘normal’ children (228 boys, 271 girls) between 9 to 12 years (M = 10.5; SD = 0.85). Sleep duration is measured by a sleep log, temperament factors Extraversion, Negative Affectivity and Effortful Control by the EATQ-R. EF is divided in working memory (Visual digit span task) and inhibition (PVT Go/No-Go). ANCOVA has showed only an association between shorter sleep duration and less working memory for introvert children and the other way around (F(2, 410) = 5.15, p = .006), but not for neutral extraverted children or high extraverted children. Also other temperament factors did not show moderation effects. Furthermore, shorter sleep was significantly related with less inhibition (r = .12), but with better working memory (r = -.52). Extraverted children differ from introverted children on working memory (F(2, 433) = 3.24, p = .040) and little Effortful Control differs from the average level of Effortful Control (F(2, 436) = 3.55, p = .030). There were no other significant results in this study. This study has shown that school performances are not only influenced by cognitive capacities, but also by sleep and child’s temperament traits.Show less
Background. Chronotype influences both sleep characteristics and behavior. Evening oriented children are more at risk to develop behavioral problems compared to morning oriented children....Show moreBackground. Chronotype influences both sleep characteristics and behavior. Evening oriented children are more at risk to develop behavioral problems compared to morning oriented children. Insufficient sleep is common during childhood and can lead to behavioral problems. However, the association of sleep duration, chronotype and behavioral problems remains unclear, especially in children. Therefore, the current study examined the degree to which sleep duration acts as a mediator of the influence of chronotype on behavioral problems in Dutch non-clinical 9-11 year old children. Method. The sample consisted 483 children, 219 boys and 264 girls, with a mean age of 10.49 year old. Sleep duration was assessed with sleep diaries. Chronotype was measured using Children´s Chronotype Questionnaire (CCTQ) and behavioral problems were assessed with Strengths and Difficulties Questionnaire (SDQ). Results. Regression analyses showed chronotype was a significant predictor of sleep duration (= -.10, p = .035), externalizing ( = .10, p = .030), but not internalizing behavioral problems (= .04, p = .410). Sleep duration was not significantly related to internalizing and externalizing behavioral problems. Furthermore, sleep duration did not act as a mediator between chronotype and internalizing (= .01, p = .900) or externalizing behavioral problems (= -.01, p = .869). Conclusions. Evening orientated children are more at risk to develop externalizing behavioral problems, which may lead to psychopathology and poor school performances. Short sleep is associated with eveningness and increased externalizing behavioral problems. Yet, sleep duration did not mediate the influence of chronotype on behavioral problems. Eveningness is identified as a possible risk factor. Early intervention to shift chronotype orientation to morningness or the use of flexible school times adjusted to optimal sleep-wake patterns might prevent problems later in life. More research is needed to provide understanding how the relation between sleep duration, chronotype and behavioral problems develops.Show less
