A new analysis has found that children from disadvantaged households sleep less and that this lack of sleep is related to a reduced cortical thickness in areas such as language, self-control, and movement.
Cortical thickness refers to the measurement of the cerebral cortex, the outermost layer of the brain, and may be measured using imaging techniques such as magnetic resonance imaging (MRI).
The recent findings, published in Brain and Behavior, provide insight into how a child's socioeconomic environment might affect their neural development.
"Socioeconomic disadvantage is prevalent in the United States and around the world, and it is known to impair children's cognitive development," says study author Emily C. Merz, an assistant professor at Colorado State University and principal investigator of the Learn Lab.
"Accumulating evidence suggests that socioeconomic differences in brain structure are at work in influencing cognitive development." Yet, the mechanisms by which these effects occur aren't well understood. We're doing research that uncovers these pathways."
"Socioeconomic disadvantage is a distal environmental fact that often has an impact on many aspects of children's immediate surroundings, including by increasing their stress." Sleep is crucial to children's development, and stress is known to affect sleep quality and quantity.
"We believe that socioeconomic disadvantage might impact on children's sleep, leading to differences in their brain development, and that these effects may partially explain socioeconomic differences in children's cognitive outcomes."
A socioeconomically diverse sample of 94 parents and their 5-to-9-year-old children was recruited through flyers and local community events in New York.
The parents then completed questionnaires regarding their children's sleep durations, sleep environment, and family routines. About one month later, the children participated in a structural brain scanning session.
Lower parental education and lower family income-to-needs ratio (indicating greater socioeconomic disadvantage) were associated with a shorter weekday sleep duration in children. In addition, shorter weekday sleep duration reduced cortical thickness in several brain regions, including the left middle temporal, right postcentral, and right superior frontal cortices.
Merz told PsyPost that a shorter weekday sleep duration contributed to a diminished gray matter in areas of the brain that are essential for self-control, language, and sensory processing. "It is possible that socioeconomic disadvantage influences these outcomes in children in part by their sleep duration."
"Ensuring that all children have opportunities for good development is critical." It's possible to support children's sleep as a way to foster good brain development. Insufficient sleep is especially prevalent among children in socioeconomically disadvantaged situations. Therefore, addressing barriers to healthy sleep in these situations is critical.
Researchers found evidence that less frequent family routines partially explained children's socioeconomic disadvantage and short-term sleep duration. These individuals differed from statements such as "Children do the same things every morning as they wake up" and "Family has certain "family time" every week when they do things together at home."
Despite his shortcomings, Merz noted that "our research isn't equipped to infer causal effects, and there are still unanswered questions" in terms of child sleep. An important next step is identifying the types of prevention or intervention strategies that are effective in promoting sleep in socioeconomically disadvantaged children.
Melissa Hansen, Katrina R. Simon, Jordan Strack, Kimberly G. Noble, and Emily C. Merz coauthored the paper.