Does the maturation of early sleep patterns predict language ability at school entry? A Born in Bradford study

Association of chronotype with language and episodic memory processing in children: implications for brain structure

Introduction

Chronotype refers to individual preference in circadian cycles and is associated with psychiatric problems. It is mainly classified into early (those who prefer to be active in the morning and sleep and wake up early) and late (those who prefer to be active in the evening and sleep and wake up late) chronotypes. Although previous research has demonstrated associations between chronotype and cognitive function and brain structure in adults, little is known regarding these associations in children. Here, we aimed to investigate the relationship between chronotype and cognitive function in children. Moreover, based on the significant association between chronotype and specific cognitive functions, we extracted regions-of-interest (ROI) and examined the association between chronotype and ROI volumes.

Methods

Data from 4,493 children (mean age of 143.06 months) from the Adolescent Brain Cognitive Development Study were obtained, wherein chronotype (mid-sleep time on free days corrected for sleep debt on school days) was assessed by the Munich Chronotype Questionnaire. Subsequently, the associations between chronotype, cognitive function, and ROI volumes were evaluated using linear mixed-effects models.

Results

Behaviorally, chronotype was negatively associated with vocabulary knowledge, reading skills, and episodic memory performance. Based on these associations, the ROI analysis focused on language-related and episodic memory-related areas revealed a negative association between chronotype and left precentral gyrus and right posterior cingulate cortex volumes. Furthermore, the precentral gyrus volume was positively associated with vocabulary knowledge and reading skills, while the posterior cingulate cortex volume was positively associated with episodic memory performance.

Discussion

These results suggest that children with late chronotype have lower language comprehension and episodic memory and smaller brain volumes in the left precentral gyrus and right posterior cingulate cortex associated with these cognitive functions.

Sleep quality relates to language impairment in children with autism spectrum disorder without intellectual disability

OBJECTIVES

This study aimed to identify sleep quality profiles of children with autism spectrum disorder (ASD), to compare these profiles with those of typically developing (TD) children, and to verify whether there are differences between them in terms of language skills.

METHODS

We evaluated the sleep quality and language skills of 47 children with ASD without intellectual disability (ID) and 32 children with TD. Using a hierarchical cluster analysis, we identified two sleep quality ASD profiles (poor and good). We then performed a series of MANCOVAs and ANOVAs to compare the sleep quality and language skills of the two ASD clusters and the TD group.

RESULTS

A main group effect (TD, "poor" cluster, and "good" cluster) was found in the total sleep quality and all its dimensions. Significant differences were revealed between the "good" and "poor" clusters in the total structural language score (F1,46 = 10.75, p < 0.001) and three of its subscales (speech: F1,46 = 9.19, p < 0.001; syntax, F1,46 = 8.61, p = 0.001; coherence: F1,46 = 11.36, p < 0.001); the total pragmatic language score (F1,46 = 7.00, p = 0.001) and three of its subscales (inappropriate initiation: F1,46 = 8.02, p = 0.001; use of context: F1,46 = 8.07, p = 0.001; nonverbal communication: F1,46 = 7.35, p = 0.001); and the social relations score (F1,46 = 9.97, p = 0.003).

CONCLUSIONS

Sleep quality in children with ASD (especially a subgroup) is worse than in children with TD. There is an association between sleep quality and language skills, both at the pragmatic and structural levels.

Sleep duration trajectories and cognition in early childhood: A systematic review

Sleep is dynamic in childhood and studies have shown the relationship between sleep and cognition in children. As the human brain is the most plastic during childhood, the study of longitudinal sleep patterns and neurocognition is an important research area. We aimed to systematically review studies that investigated sleep duration trajectories and cognition in typically-developing children. We searched four databases for articles published between 2003 to October 2023. We included observation studies of children with sleep duration trajectories as a predictor and outcomes related to cognition, memory, language, developmental milestones, intelligence or executive function. We excluded studies where children had atypical development or completed the sleep and neurocognitive assessments after six and 12 years of age respectively. Out of 752 articles identified, 511 were screened and 23 full texts were assessed. The selected studies included three single trajectory and four multiple group trajectories studies. We found associations between both types of trajectories and cognitive development. Overall, children with longer sleep trajectories or more mature sleep pattern with rapid decrease in sleep duration, had better performance scores in developmental assessment tools, and intelligence tests. Findings for language and executive functioning were mixed, whereby some studies found associations and others did not.

Early nap cessation in young children as a correlate of language and psychosocial outcomes: Evidence from a large Canadian sample

OBJECTIVES

Most children stop napping between 2 and 5years old. We tested the association of early nap cessation (ie, children who stopped before their third birthday) and language, cognition functioning and psychosocial outcomes.

METHODS

Data were from a national, longitudinal sample of Canadian children, with three timepoints. Children were 0-to-1 year old at T1, 2-to-3 years old at T2, and 4-to-5 years old at T3. Early nap cessation was tested as a correlate of children's psychosocial functioning (cross-sectionally and longitudinally), cognitive function (longitudinally), and language skills (longitudinally). There were 4923 children (50.9% male; 90.0% White) and their parents in this study who were included in the main analyses. Parents reported on demographics, perinatal and developmental variables, child functioning, and child sleep. Children completed direct assessments of receptive language and cognitive ability. Nap cessation, demographic, and developmental-control variables were tested as correlates of cross-sectional and longitudinal outcomes using linear regression (with a model-building approach).

RESULTS

Early nap cessation correlated with higher receptive language ability (β = 0.059 ± 0.028) and lower anxiety (β = -0.039 ± 0.028) at T3, after controlling for known correlates of nap cessation, nighttime sleep, and other sociodemographic correlates of the outcomes. Cognitive ability, hyperactivity-inattention, and aggression were not correlated with nap cessation.

CONCLUSIONS

Early nap cessation is related to specific benefits (ie, better receptive language and lower anxiety symptoms). These findings align with previous research. Future research should investigate differences associated with late nap cessation and in nap-encouraging cultures, and by ethnicity.

Trajectories of reported sleep duration associate with early childhood cognitive development

STUDY OBJECTIVES

Examine how different trajectories of reported sleep duration associate with early childhood cognition.

METHODS

Caregiver-reported sleep duration data (n = 330) were collected using the Brief Infant Sleep Questionnaire at 3, 6, 9, 12, 18, and 24 months and Children's Sleep Habits Questionnaire at 54 months. Multiple group-based day-, night-, and/or total sleep trajectories were derived-each differing in duration and variability. Bayley Scales of Infant and Toddler Development-III (Bayley-III) and the Kaufman Brief Intelligence Test- 2 (KBIT-2) were used to assess cognition at 24 and 54 months, respectively.

RESULTS

Compared to short variable night sleep trajectory, long consistent night sleep trajectory was associated with higher scores on Bayley-III (cognition and language), while moderate/long consistent night sleep trajectories were associated with higher KBIT-2 (verbal and composite) scores. Children with a long consistent total sleep trajectory had higher Bayley-III (cognition and expressive language) and KBIT-2 (verbal and composite) scores compared to children with a short variable total sleep trajectory. Moderate consistent total sleep trajectory was associated with higher Bayley-III language and KBIT-2 verbal scores relative to the short variable total trajectory. Children with a long variable day sleep had lower Bayley-III (cognition and fine motor) and KBIT-2 (verbal and composite) scores compared to children with a short consistent day sleep trajectory.

CONCLUSIONS

Longer and more consistent night- and total sleep trajectories, and a short day sleep trajectory in early childhood were associated with better cognition at 2 and 4.5 years.

Nap effects on preschool children’s learning of letter‐sound mappings

This study explored whether a daytime nap aids children's acquisition of letter‐sound knowledge, which is a fundamental component for learning to read. Thirty‐two preschool children in Sydney, Australia (M_age = 4 years;3 months) were taught letter‐sound mappings in two sessions: one followed by a nap and the other by a wakeful period. Learning was assessed by explicit letter‐sound mappings (“Which sound does this letter make?”) and knowledge generalization tasks (“Here's Tav and Cav, which one is /kav/?”). Results from the knowledge generalization task showed better performance after a nap than after wake. However, no nap benefit was found for explicit letter‐sound knowledge. This study provides initial evidence that naps could be beneficial for preschool children's learning of letter‐sound mappings.

Prior Exposure and Toddlers' Sleep-Related Memory for Novel Words

Children can easily link a novel word to a novel, unnamed object—something referred to as fast mapping. Despite the ease and speed with which children do this, their memories for novel fast-mapped words can be poor unless they receive memory supports such as further exposure to the words or sleep. Axelsson, Swinton, Winiger, and Horst (2018) found that 2.5-year-old children who napped after fast mapping had better retention of novel words than children who did not nap. Retention declined for those who did not nap. The children received no memory supports and determined the word-object mappings independently. Previous studies report enhanced memories after sleeping in children and adults, but the napping children’s retention in the Axelsson et al. study remained steady across time. We report a follow-up investigation where memory supports are provided after fast mapping to test whether memories would be enhanced following napping. Children’s retention of novel words improved and remained greater than chance; however, there was no nap effect with no significant difference between the children who napped and those who did not. These findings suggest that when memory supports are provided, retention improves, and the word–object mappings remain stable over time. When memory traces are weak and labile, such as after fast mapping, without further memory supports, sleeping soon after helps stabilise and prevent decay of word–object mappings.