In their first year of life, babies who later develop autism tend to show unusual brain responses when watching a moving image of a face that looks toward or away from them. This new finding suggests that direct measures of brain activity in infants as young as six months may help predict the later development of autism. However, the researchers caution that this study is just one step toward the long-term goal of earlier diagnosis and intervention. The results appear online today in the journal Current Biology.
"Our findings demonstrate, for the first time, that direct measures of brain functioning during the first year of life can be associated with a later diagnosis of autism," says senior author Mark Johnson, Ph.D., of the Centre for Brain and Cognitive Development, at the University of London’s Birkbeck College. The observed differences in brain responses become clear well before the emergence of autism’s behavioral symptoms, he adds. Psychologist Mayada Elsabbagh, Ph.D., is the study’s lead author, and their team is part of Autism Speaks’ High Risk Baby Siblings Research Consortium.
The behaviors characteristic of autism spectrum disorder (ASD) emerge over the first few years of life, and a firm diagnosis is currently possible only after two years of age. Yet a growing body of research suggests that ASD has its roots in crucial periods of prenatal and early infant brain development and that early intervention can improve outcomes. For this reason, Autism Speaks and others continue to fund research on earlier diagnosis and the identification of signs that a baby may be at increased risk of developing autism. Indeed, this is the major emphasis of the Baby Siblings Research Consortium.
The University of London team studied 104 six- to ten-month-old babies, 54 of whom were at elevated risk of developing autism because they had an older brother or sister on the spectrum. The researchers used a sensor cap placed on the scalp to register brain activity while the babies viewed dynamic images of faces that switched from looking at them to looking away from them, or vice versa (images above).
This experimental laboratory test showed that most infants who did not go on to develop autism showed clear differences in brain activity when viewing images of a face looking toward them versus one looking away. By contrast, infants who did go on to develop autism tended to show little difference in brain activity when viewing the two types of shifting gazes.
Earlier studies have shown that the human brain displays characteristic patterns of activity in response to eye contact with another person. This response appears to be critical for face-to-face social interactions. Research has also shown that older children with autism have atypical patterns of eye contact as well as atypical brain responses when making eye contact.
In the new study, a few babies who demonstrated the unusual pattern of brain activity did not develop autism, just as a few babies who demonstrated typical brain activity did develop the disorder. In other words, the atypical brain activity flagged elevated risk for developing autism. But it did not indicate that a baby would certainly develop it. The researchers called for further studies on whether there may be protective factors that might reduce autism risk in infants who demonstrate this or other early warning signs.
"Researchers studying infants at risk for ASD are now able to show differences in brain function as early as six months of age,” says Autism Speaks Director for Environmental Science Alycia Halladay, Ph.D., in commenting on the study’s importance. “In the future,” she says, “these measurements may become useful and sensitive predictors of autism in combination with other signs and symptoms.” Halladay helped organize the Baby Siblings Research Consortium in 2003 and continues to help coordinate its activities. “Understanding the earliest signs and markers for symptoms of ASD will help ensure that intervention is delivered as soon as possible,” she says of its mission.
In addition to supporting the Baby Siblings Research Consortium, Autism Speaks is currently funding a number of infant studies to further understanding of autism’s early signs, symptoms and risk-reducing interventions. You can explore these and other funded studies using our grant search engine.