Impact of Sleep Characteristics on Daytime Functioning in Children

Abstract

Sleep appears to play a critical role in regulating daytime functioning in children. However, few child-focused studies have used objective measures of sleep and examined its role in emotional functioning, memory, and attention. This dissertation consisted of 2 studies. Study 1 examined children’s typical sleep and how it correlates with daytime functioning in 32 typically developing children (14 boys, 18 girls), 8 to 12 years of age (M=9.8 y, SD=1.4). Participants wore actigraphs (recording devices that provide information about sleep and activity) for 1 week and then completed tasks to measure emotional functioning, memory, and attention. On average, children slept less than 9 h per night, which is approximately 1 h less than the recommended duration for this age. Older children had shorter sleep durations, higher sleep efficiency, and later sleep onset times. Correlational analyses revealed that within this group of typically developing children, small variations in sleep were associated with statistically significant effects on daytime functioning. Specifically, shorter sleep duration was associated with increased negative affective response, and lower sleep efficiency was associated with poorer performance on a divided attention task. Study 2 involved experimental manipulation of sleep duration in the same sample of children. Following a week of typical sleep, each child was randomly assigned to go to bed 1 h earlier for 4 nights (Extended condition) or 1 h hour later for 4 nights (Restricted condition) relative to their typical bedtime. Each child then completed the opposite condition. Following each condition, emotional functioning, memory, and attention were assessed using objective and subjective measures. The sleep manipulation was effective: the children slept significantly longer in the Extended (M=9.3 h, SD=0.6) versus Restricted (M=8.1 h, SD=0.7) condition, and children were significantly sleepier in the Restricted condition according to parent, child, and research assistant report. Positive affective response, emotion regulation, memory, and aspects of attention were worse in the Restricted, compared to Extended condition. These studies provide evidence that modest variations in sleep can have substantial effects on daytime functioning in children. Clinical implications are discussed, including the importance of identifying sleep problems and promoting healthy sleep habits in children.