Elementary school-age children who sleep less than nine hours a night have significant differences in certain brain regions responsible for memory, intelligence and well-being compared with those who sleep between the recommended nine and 12 hours a night, according to a new study led by researchers at the University of Maryland School of Medicine (UMSOM). Such differences were correlated with greater mental health problems, such as depression, anxiety and impulsive behaviors, in those who did not sleep. Inadequate sleep was also linked to cognitive difficulties with memory, problem solving and decision making. The findings were published today in the journal Lancet Child & Adolescent Health.
The American Academy of Sleep Medicine recommends that children ages 6 to 12 get 9 to 12 hours of sleep a night on a regular basis to promote optimal health. Until now, no study has examined the lasting impact of sleep deprivation on the neurocognitive development of preadolescents.
To conduct the study, researchers examined data collected from more than 8,300 children ages 9 to 10 who were enrolled in the Adolescent Brain Cognitive Development (ABCD) study. They reviewed MRIs, medical records, and surveys completed by participants and their parents at enrollment and at a two-year follow-up visit at 11 or 12 years of age. Funded by the National Institutes of Health (NIH), the ABCD study is the largest long-term study of brain development and child health in the US.
We found that children who hadn’t gotten enough sleep — less than nine hours a night — at the start of the study had less gray matter or a smaller volume in certain areas of the brain responsible for controlling attention, memory, and inhibition compared with those with healthy sleep habits. . These differences persisted after two years, a worrying finding that suggests long-term harm for those who don’t get enough sleep.”
Ze Wang, PhD, study corresponding author, professor of diagnostic radiology and nuclear medicine at UMSOM
This is one of the first findings to demonstrate the potential long-term impact of sleep deprivation on children’s neurocognitive development. It also provides substantial support for current sleep recommendations for children, according to Dr. Wang and his colleagues.
In follow-up evaluations, the research team found that participants in the sufficient sleep group tended to gradually sleep less over two years, which is normal as children move into adolescence, while sleep patterns of participants in the insufficient sleep group did not change much. The researchers controlled for socioeconomic status, gender, puberty status and other factors that could affect how much sleep a child gets and affect the brain and cognition.
“We tried to match the two groups as closely as possible to help us better understand the long-term impact of sleep deprivation on the preadolescent brain.” said Dr. Wang. “Further studies are needed to confirm our finding and see if any intervention can improve sleep habits and reverse neurological deficits.”
The American Academy of Pediatrics encourages parents to promote good sleep habits in their children. His advice includes making getting enough sleep a family priority, sticking to a regular sleep routine, encouraging physical activity during the day, limiting screen time, and eliminating screens altogether an hour before bed.
The study was funded by NIH. Fan Nils Yang, PhD, a postdoctoral fellow in Dr. Wang’s lab, is a co-author of the study. Weizhen Xie, PhD, a researcher at the National Institute of Neurological Disorders and Stroke, is also a co-author of the study. UMSOM faculty members Thomas Ernst, PhD, and Linda Chang, MD, MS, are co-principal investigators of the ABCD study at the Baltimore site, but were not involved in data analysis of this new study.
“This is a crucial finding of the study that points to the importance of conducting long-term studies of the developing child’s brain.” said E. Albert Reece, MD, PhD, MBA, Executive Vice President for Medical Affairs, UM Baltimore, and John Z. and Akiko K. Bowers Distinguished Professor and Dean, University of Maryland School of Medicine. “Sleep can often be overlooked during busy childhood days filled with homework and extracurricular activities. Now we see how detrimental it can be to a child’s development.”