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

Abstract

Children's vocabulary ability at school entry is highly variable and predictive of later language and literacy outcomes. Sleep is potentially useful in understanding and explaining that variability, with sleep patterns being predictive of global trajectories of language acquisition. Here, we looked to replicate and extend these findings. Data from 354 children (without English as an additional language) in the Born in Bradford study were analysed, describing the mean intercepts and linear trends in parent-reported day-time and night-time sleep duration over five time points between 6 and 36 months-of-age. The mean difference between night-time and day-time sleep was predictive of receptive vocabulary at age five, with more night-time sleep relative to day-time sleep predicting better language. An exploratory analysis suggested that socioeconomic status was predictive of vocabulary outcomes, with sleep patterns partially mediating this relationship. We suggest that the consolidation of sleep patterns acts as a driver of early language development.

Systematic Review of the Effects of Sleep on Memory and Word Learning in Infancy

“…These findings suggested that naps are important for lexical development, perhaps providing multiple occasions to consolidate and retain new information prior to nocturnal sleep. Conversely, Dionne et al (2011) and Knowland et al (2022) identified the benefits of longer and less interrupted nighttime over daytime sleep to subsequent vocabulary growth, with children with longer daytime sleep also being more likely to develop language delays in later years (Dionne et al, 2011). These results supported the idea that sleep consolidation may reflect brain maturation in preschoolers (Lam et al, 2011;Riggins & Spencer, 2020).…”

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

“…Lam, et al [83] found that napping was associated with poorer nocturnal sleep and lower vocabulary size. Other studies have found that less consolidated sleep (i.e., still napping) was associated with poorer vocabulary size later in development [84,85] and better delayed memory [70]. The greater number of non-habitual nappers in the wake condition raises the question of whether they were more cognitively advanced than the children in the nap condition that had more habitual nappers.…”

Mother–child interactions and child anger proneness as antecedents of changes in sleep during the preschool period.

“…Sleep efficiency, defined as the percentage of time in bed spent asleep, increases as a result of a decrease in night awakenings. Moreover, the proportion of daily sleep that occurs during the night (i.e., proportion of nighttime sleep) increases because nighttime sleep duration remains stable while daytime sleep decreases (Knowland et al, 2022; Plancoulaine et al, 2018). Although these trends have initially been identified in cross-sectional studies (see Galland et al, 2012), sleep scholars are increasingly interested in modeling formal sleep trajectories by using repeated sleep measures within longitudinal designs.…”

“…Moreover, increasing evidence suggests that sleep plays a role in the healthy development of brain functions and structures (Dutil et al, 2018). Importantly, scholars have hypothesized that above and beyond age-specific sleep patterns, age-related changes in sleep during the preschool years may be meaningful and reflect neurophysiological maturation (Jenni & Carskadon, 2012; Knowland et al, 2022; Lam et al, 2011). In line with this, recent studies show that sleep undergoes substantial changes during the preschool years and that these changes, in and of themselves, relate to cognitive functioning, brain morphology, academic achievement, internalizing problems, health, and illness (Bernier et al, 2021; Hoyniak et al, 2020; Hsu, 2017; Kocevska et al, 2017).…”