BY STEVEN REINBERG, HealthDay Reporter
Sleep problems in baby’s first year may affect growth of the hippocampus and may also precede an autism diagnosis, researchers say.
In the study of 400 6- to 12-month-old infants, the investigators found that those diagnosed with autism were more likely to have had trouble falling asleep. Sleep time is prime time for brain development, the study authors noted.
“The hippocampus is critical for learning and memory, and changes in the size of the hippocampus have been associated with poor sleep in adults and older children,” said lead author Kate MacDuffie, a postdoctoral researcher at the University of Washington Autism Center, in Seattle.
As many as 80% of children with autism have sleep problems, according to the center’s director, Annette Estes.
“In our clinical experience, parents have a lot of concerns about their children’s sleep, and in our work on early autism intervention, we observed that sleep problems were holding children and families back,” Estes said in a university news release.
It’s too soon, however, to tell if sleep patterns predict autism, she said.
Sleep patterns in the first years of life change as infants go from sleeping around the clock to a more adult-like sleep/wake pattern. Without more study, Estes said, it’s not possible to determine whether sleep problems indicate an early sign of an increased risk for autism.
There might be a biological component to sleep problems for some children with autism, however, she said.
For the study, the researchers evaluated children at 6, 12 and 24 months of age, and questioned parents about the children’s sleep habits. Infants also had MRI scans.
The researchers deemed 127 babies at low risk of autism because they had no family history of the disorder. Of the roughly 300 children who were initially considered high-risk, 71 were diagnosed with autism at age 2.
In addition, MacDuffie’s team compared repeat MRI brain scans with the children’s sleep histories. Sleep problems were more common among the infants diagnosed with autism, as was a larger hippocampus. No other parts of the brain were affected.
Other studies have linked “overgrowth” in different brain structures to social, language and behavioral aspects of autism.
While the new research showed a link between brain structure and sleep problems among children who were later diagnosed with autism, it could not prove that there was a causal relationship.