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Thesis Format

Integrated Article

Degree

Doctor of Philosophy

Program

Psychology

Supervisor

Reid, Graham J.

Abstract

Experimental sleep restriction yields data that shows how sleep loss causes declining daytime function in cognition and behaviour, yet few experimental studies have been conducted with preschool children between the ages of 3 and 5 years of age. During the preschool period children achieve important milestones in cognitive development while a significant minority also experience behavioural sleep problems regularly. There is no empirically-based consensus on the impact of reduced sleep in preschool children. To address this gap, parents of preschool children were recruited in a participatory design study to provide input in designing an accessible home-based experimental sleep study with conditions of sleep restriction and sleep fragmentation. Child participants in the experimental study wore actigraphs for 10 days to record their sleep during 7 days of baseline measurement, followed by 3 days of experimental measurement. Children were randomly assigned to a control condition, a 40-minute or 20-minute sleep restriction condition, or to a sleep fragmentation condition where they were kept awake for 20 minutes after first falling asleep. Daytime cognitive outcomes were assessed after the third experimental night using an assessment battery of developmentally-appropriate executive function measures of working memory, response inhibition, and delay of gratification. Contrary to expectation, less sleep relative to baseline was not associated with measured executive function performance decrements among children without pre-existing sleep problems. Experimentally imposing greater sleep restriction before assessment may be necessary to measure changes in executive functioning measures for this age group.

Summary for Lay Audience

Parents, caregivers and health professionals generally assume that negative outcomes such as poor behaviour, inattention, and more negative feelings such as anger or sadness result from shorter sleep. These assumptions are often applied to young children of preschool age (between 3 and 5 years old), particularly because this is an age group in a substantial minority of children delay bedtime or continue to wake during the night and require parents to attend to them before falling asleep again. However, there have still been very few studies that look at how getting less sleep affects young children during the daytime. In this research project, the overall goals were 1) to recruit parents of young children to find out how to design a study where parents would be willing and able to deprive their children of some sleep, and 2) to run this experiment with children between 3 and 5 years old to find out whether mild sleep deprivation affected children’s performance on tasks that were related to the underlying development of thinking and behaviour. Parents of children in the target range were interviewed over the telephone in order to help plan the research. In the main research study, some children were assigned to receive less sleep, to be woken up at night, or to have no changes in their sleep. Children’s variability in sleep duration on different days of the study resulted in challenges when comparing children’s sleep restriction based on their assigned groups. The main research study found no differences in children’s executive functioning performance based on sleep restriction; contrary to expectations, children who experienced greater sleep restriction during the experimental phase performed better on the measure of delay of gratification. More research will need to be conducted to determine how much sleep restriction may affect children’s thinking and behaviour.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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