Scientists find autism signs in infants
Earlier diagnosis could help with behaviour therapy
Researchers have detected changes in brain development in babies with autism as young as six months old — half a year or more before parents typically begin to notice symptoms of the condition.
The results shed light on the fundamental differences in the brains of children with autism and could help lead to earlier detection and treatment, says co-author Geraldine Dawson, chief science officer at Autism Speaks, which helped fund the study in the American Journal of Psychiatry.
Parents often begin to notice autistic symptoms in children at age one or two, and autism typically isn’t diagnosed until the child reaches about five. Many parents perceive their child’s symptoms appeared suddenly, a phenomenon that helped contribute to the now-debunked idea that autism is caused by vaccines, says autism researcher Christine Wu Nordahl, from the University of CaliforniaDavis MIND Institute, who wasn’t involved in the new report.
The new study suggests that changes in the brain’s communication pathways may take place silently, long before children begin to exhibit telltale problems communicating and socializing, or exhibiting repetitive behaviours, Dawson says.
Other studies, such as a January article in Current Biology, have detected differences in how the brain reacts in the gazes of babies with autism as young as six to 10 months.
Eventually, researchers hope to be able to find a pattern in these brain scans that could allow them to spot which high-risk babies are likely to have autism, and begin intensive behavioural therapy, which is most effective when begun early, Dawson says. Even if babies get into treatment by 18 months old, Dawson says, “there has been a long period of time when the baby’s brain has been developing abnormally,” which could make the child’s behaviour harder to change.
“A lot of the kids in this study, they looked pretty good socially at six months,” says senior author Joseph Piven, director of Carolina Institute for Developmental Disabilities in Chapel Hill. “But by 12 months of age, it was almost as if someone had pulled the curtain down.”
In the study, researchers performed brain scans, using MRIS, of 92 babies with an older sibling who had autism. Studies show that these younger siblings have a nearly 20 per cent risk of being diagnosed with the condition. Overall, about one in 110 American children has an autism spectrum disorder, according to the Centers for Disease Control and Prevention.
Researchers scanned the babies’ brains at ages six months, one year and two years of age, creating three-dimensional pictures depicting changes over time in the brain’s “white matter,” which include bundles of nerve fibres and their protective coatings. These fibre tracks act like communication paths between brain regions, Dawson says.
Twenty-eight children went on to develop autism. When researchers looked at their scans, they saw key differences in the way these pathways developed, Piven says. At age six months, these pathways were more developed than those of typically developing children. By the time children were two, the brain development of the kids with autism had fallen behind.
“Their brains aren’t organizing as rapidly,” author Jason Wolff of the Carolina Institute says.
Nordahl called the study “remarkable” and a “great first step.” But she notes that the absolute differences among the children are small. The findings need to be repeated by other researchers before doctors can begin to create a reliable early-detection system.
The study has other limitations, says Charles Nelson, a professor of pediatrics and neuroscience at Harvard medical school. The findings would be stronger if researchers compared them to those of a control group of normal-risk children who don’t come from families with other children with autism. He questioned why 30 per cent of the high-risk children were diagnosed with autism, a rate that’s 50 per cent higher than expected. Nelson also notes that it can be hard to definitively diagnose autism at age two, and that a child’s diagnosis can change over time.
Dawson says researchers still have many questions. She wonders, for example, if brain scans will spot differences in autistic brains even earlier than six months, and if the differences could even begin in the womb.
Autism Speaks is funding research into exercises that parents can perform with their babies to stimulate language and social development, in an effort to reinforce and strengthen those brain connections. In these exercises, whose results aren’t yet known, she says researchers teach parents to play with babies in simple ways they hope will diminish the child’s symptoms by “changing the course of brain development.”