In the brain, an earlier sign of autism
In their first year of life, babies who will go on to develop autism already show different brain responses when someone looks at or away from them. Although the researchers are careful to say that the study, reported online on January 26 in the Cell Press journal Current Biology, is only a first step toward earlier diagnosis, the findings do suggest that direct brain measures might help to predict the future development of autism symptoms in infants as young as six months.
“Our findings demonstrate for the first time that direct measures of brain functioning during the first year of life associate with a later diagnosis of autism—well before the emergence of behavioral symptoms,” said Mark Johnson of Birkbeck College, University of London.
The behaviors characteristic of autism emerge over the first few years of life, and firm diagnoses are now made in children only after the age of two. As a result, the vast majority of research on autism has necessarily concentrated on children two and older, who have already been diagnosed.
“We still know very little about the earliest appearing symptoms and warning signs,” Johnson said.
To find out more, his team looked to six- to ten-month-old babies at greater risk of developing autism later in development because they had an older brother or sister with the condition. The researchers used passive sensors placed on the scalp to register brain activity while the babies viewed faces that switched from looking at them to looking away from them or vice versa.
Earlier studies have shown that the human brain shows characteristic patterns of activity in response to eye contact with another person. That response is a critical foundation for face-to-face social interactions, and it is well known that older children diagnosed with autism show unusual patterns of eye contact and of brain responses to social interactions that involve eye contact.
Early Signs of Autism Identified in Infants
Canadian researchers say they can recognize the early signs of autism in children as young as 6 months old, and they hope their findings will lead to better early treatments for the disorder.
In their ongoing study that now includes autism centers across 14 cities in Canada and the U.S., the researchers are following the progression of younger siblings of children with autism.
According to the National Alliance for Autism Research, a child born into a family in which an older child has been diagnosed with autism is 50 times more likely to develop the disorder than a child with no afflicted siblings.
In this study, researchers show that by age 1, siblings who are later diagnosed with autism may be distinguished from other siblings by early developmental behaviors.
“This is groundbreaking work that is pushing the frontier of what we know about the biological nature of autism, and why it emerges so early in life,” says researcher Lonnie Zwaigenbaum, MD, of Ontario’s McMaster University. “Our hope is that it will lead to the development of new and earlier treatments that could make a huge difference for these children.”
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By Salynn Boyles
WebMD Health News
The new studies reveal that the brains of infants who will go on to develop autism already process social information in a different way. “At this age, no behavioral markers of autism are yet evident, and so measurements of brain function may be a more sensitive indicator of risk,” Johnson said.
It is important to note, however, that there were cases in which individual babies who showed these differences in brain function were not later diagnosed and vice versa. In other words, the method would require further refinement, most likely in combination with other factors, to form the basis of a predictor accurate enough for clinical use.