Sleep as a protective factor of children's executive functions: A study during COVID-19 confinement

Abstract

Confinements due to the COVID-19 outbreak affected sleep and mental health of adults, adolescents and children. Already preschool children experienced acutely worsened sleep, yet the possible resulting effects on executive functions remain unexplored. Longitudinally, sleep quality predicts later behavioral-cognitive outcomes. Accordingly, we propose children's sleep behavior as essential for healthy cognitive development. By using the COVID-19 confinement as an observational-experimental intervention, we tested whether worsened children's sleep affects executive functions outcomes 6 months downstream. We hypothesized that acutely increased night awakenings and sleep latency relate to reduced later executive functions. With an online survey during the acute confinement phase we analyzed sleep behavior in 45 children (36-72 months). A first survey referred to the (retrospective) time before and (acute) situation during confinement, and a follow-up survey assessed executive functions 6 months later (6 months retrospectively). Indeed, acutely increased nighttime awakenings related to reduced inhibition at FOLLOW-UP. Associations were specific to the confinement-induced sleep-change and not the sleep behavior before confinement. These findings highlight that specifically acute changes of children's nighttime sleep during sensitive periods are associated with behavioral outcome consequences. This aligns with observations in animals that inducing poor sleep during developmental periods affects later brain function.

Fig 1. Working model.

Sleep behavior is an umbrella protecting developmental outcomes from influences of contextual stress [–66].

Fig 2. Overview of the study design.

During April 2020, the first survey was completed to assess parent-reported sleep of young children during the confinement «during-CONFINEMENT» with the identical questions addressing the time before the confinement «pre-CONFINEMENT». In November 2020, a “FOLLOW-UP” was completed to assess executive functions with a questionnaire referring to children’s behavior retrospectively for the preceding 6 months.

Fig 3. Overview of BRIEF-P standard analysis to quantify executive functions in preschool children, including computation of subscales, indices, and composite score.

Fig 4. Acute changes in sleep behaviors in preschool children during the COVID-19 confinement.

In pink, distribution of sleep behaviors is presented for pre-CONFINEMENT, orange refers to sleep during-CONFINEMENT. Dots represent values of individual subjects. Significance level based on a Wilcoxon signed-rank test is indicated as *p<0.01.

Fig 5. Prediction of executive functions indices by confinement-induced sleep behavior changes in young children.

(A): The change in sleep is computed from subtraction pre-to-during-CONFINEMENT in each sleep behavior. Missing values indicate that sleep behavior did not survive the statistical backward selection, b indicates unstandardized beta coefficients, p represents corrected p-values from the linear mixed model. (B) Evolution of the change pre-to-during-CONFINEMENT of Nighttime awakenings and his association with the Inhibitory Self Control Indices. Dashed line automatically fitted with Excel software.

Fig 6. Prediction of executive function subscales by confinement-induced sleep behavior changes in young children.

(A)The change in sleep is computed from subtraction pre-to-during-CONFINEMENT in each sleep behavior. Missing values indicate that sleep behavior did not survive the statistical backward selection, b indicates unstandardized beta coefficients, p represents corrected p-values from the linear mixed model. (B) Evolution of the change pre-to-during-CONFINEMENT of Nighttime awakenings and his association with the Inhibit and Emotional Control Subscale. Dashed line automatically fitted with Excel software.