Sleep and Adaptation for Preschool Children

Auburn University, Auburn AL

Investigators

Abstract

Sleep is a critical element of adaptive functioning across the whole human life cycle, and is crucial during infancy, childhood, and adolescence. The fundamental importance of sleep, as both as state and a process, for development has been recognized by developmental scientists for over 20 years and studies have linked quantitative (e.g., total amount of sleep per night) and qualitative (e.g., sleep efficiency--time in bed that the person is actually asleep) sleep parameters to a broad range of health-relevant outcomes in samples of children. Researchers also have identified many biological and social factors that influence both sleep quantity and quality, however, the bulk of research with children has focused on infancy, school-age children, and adolescents; with relatively little research attention devoted to the impact of sleep during early childhood (nominally 2.5-6 years). Moreover, most studies covering the early childhood period relied on subjective reports from sleep diaries or questionnaires completed by parents and examined problems associated with medical conditions or with sleep deficits. Finally, most of these studies recruited families in which children were cared for at home by a parent. This study of up to 270 children (90 in each of 3 consecutive years), recruited between the ages of 2.5 and 4.5 years of age and followed up to two years after initial enrollment, starts from the premise that sleep parameters are continua ranging from maladaptive to optimal, with most children falling in a mid-range that is adequate for normal growth and functioning, rather than from the premise that sleep parameters are either "disordered" or not. The investigators for this project will recruit the sample from a high-quality early education center in a large metropolitan area from the Southeastern USA. Selecting such a sample allows them to consider both the positive growth promoting benefits of sleep as well as the constraints on development and adaptation imposed by less adequate sleep. The sample also allows generalization of prior research on home-reared children to the most common child-care setting now being used in the USA (group care). The researchers will also measure sleep objectively by using activity monitors worn by the children over a week's time, which makes it possible to examine the trajectories of nighttime and naptime sleep in greater detail than is possible from parent reports; although the project will retain the parent diary method so as to provide contextual information (e.g., any illnesses the child suffered while sleep was monitored; medications taken, etc.) to supplement the sleep measures from activity monitoring. The investigators also will conduct a comprehensive assessment of child adaptation in their homes and early education center classrooms, including the domains of social, emotional, cognitive, and academic functioning. These assessments involve extensive direct observations of child behavior at home and in the classroom, standard tests of receptive vocabulary and age-appropriate academic achievement, laboratory tasks designed to assess self-regulation, emotion knowledge, executive functioning, and parent/child and teacher/child relationships. The study will provide fundamental information about the developmental course of sleep (quantity and quality) over early childhood and the environmental factors that constrain and/or promote adequate and optimal sleep. Because children will be observed repeatedly over the course of the study, the researchers will also be able to examine the temporal/causal influences of parent/child relationships on sleep (and vice versa), as well as the relative influences of both sleep and adult/child relationships on the quality of social/emotional and cognitive/academic functioning assessed in the classroom. A fourth valuable contribution of the study arises as a consequence of the sample itself. The early education program collaborating with the study serves a multi-ethnic but predominantly middle-class population (about 30% ethnic minority status families enrolling children) but also serves children from low-resource families (~10% of total enrollment). This distribution of children will permit testing hypotheses concerning health disparities between minority ethnic status and/or more economically challenged groups (compared to majority ethnic status and/or middle SES groups) with regard to sleep and its consequences. In addition to these fundamental contributions to the science of sleep, this study will likely have broad implications for childcare policy, curriculum development for young children, teacher training, and parent education.