MONDAY, Oct. 29, 2018 (HealthDay News) -- Naps have been shown to help young children learn, but researchers report they may have the opposite effect on children with Down syndrome.
"In children with Down syndrome, there's something about having a nap right after learning that seemed to keep them from retaining information as well, which is totally different than what happened in typically developing children," said study author Jamie Edgin. She is an associate professor of psychology at the University of Arizona.
Edgin and her colleagues assessed 25 children with Down syndrome, average age 4.5 years, and 24 typically developing children, average age 2.5 years.
The researchers tested the children's ability to remember new words 5 minutes after they'd learned the words. The children were then tested again 4 hours after they'd learned the words and stayed awake, 4 hours after they'd learned the words and had a nap, and 24 hours later.
The typically developing children were more likely to remember the new words 4 hours and 24 hours after learning them if they took a 90-minute nap shortly after learning the word.
However, if the children with Down syndrome napped after learning the words, they were much less likely to remember them 4 hours and 24 hours later than if they didn't nap, the findings showed.
The study was published Oct. 29 in the Proceedings of the National Academy of Sciences.
Further research is needed to learn why naps may harm learning in children with Down syndrome, said Edgin, who noted that REM sleep is reduced in people with Down syndrome. REM is a normal stage of sleep that is characterized by rapid eye movements, more dreaming and bodily movement, and faster pulse and breathing.
"There might be something about getting too little REM sleep and not completing that REM stage that could be related to difficulties with retention," Edgin said in a university news release.
"There are some recent studies that suggest that people show poorer retention if they get just a little bit of REM than if they get a whole REM cycle," she explained. "More work needs to be done, but REM sleep is definitely something to consider."
The National Down Syndrome Society has more on Down syndrome.