Measuring Brain Growth in Infancy May Predict Autism

Bridget M. Kuehn

February 15, 2017

Measuring changes in the volume and surface area of the brain during the first year of life may help scientists identify which high-risk children will develop autism, suggests a study published online February 15 in Nature.

If the study results are replicated, the findings could one day help clinicians identify children who will develop the disorder and enable very early interventions.

Studies have long shown that individuals with autism have enlarged brains compared with nonaffected individuals. But it hasn't been clear when this change in brain size occurs or how it effects the emergence of the behavioral characteristics associated with autism, explain Heather Cody Hazlett, PhD, an assistant professor at the University of North Carolina (UNC) School of Medicine in Chapel Hill, and colleagues.

To explore this relationship, Dr Hazlett and colleagues used MRI to measure brain growth in 106 high-risk infants with siblings who have autism spectrum disorder and 42 infants considered at low risk for the disorder. At ages 6, 12, and 24 months, the infants underwent behavioral assessments and high-resolution brain MRI.

In 15 high-risk infants who were diagnosed with autism at 24 months, the imaging revealed "hyperexpansion" of cortical surface area between 6 and 12 months. Then, between 12 and 24 months, they developed brain overgrowth. This overgrowth coincided with the emergence of symptoms and was linked to how severe the symptoms were.

Given the strength of this association, the researchers developed a computer algorithm to predict which high-risk children would later be diagnosed with autism. They used previously collected data on brain growth among infants between 6 and 12 months of age, including 34 who went on to develop the disorder and 145 who did not.

In cross-validation testing, the algorithm correctly predicted which children would be diagnosed with autism 81% of the time (accurately identifying 30 of 37 who were diagnosed) and had a sensitivity of 88%. It correctly predicted which children would not develop the disorder 97% of the time (138 of 142).

"Our study shows that early brain development biomarkers could be very useful in identifying babies at the highest risk for autism before behavioral symptoms emerge," said senior author Joseph Piven, MD, director of the Carolina Institute for Developmental Disabilities at UNC, in a press release.

Already, studies have suggested that starting interventions early — shortly after behavioral symptoms emerge — tends to provide the greatest benefits. So, having a test available that could identify the disorder earlier might facilitate even earlier therapy.

"If we are able to replicate these results in further studies, these findings promise to change how we approach infant and toddler screening for autism, making it possible to identify infants who will later develop autism before the behavioral symptoms of autism become apparent," said coauthor Robert T. Schultz, PhD, director of the Center for Autism Research at the Children's Hospital of Philadelphia, Pennsylvania, in the release.

Additionally, Dr Schultz noted the imaging results show precisely where unusual brain development patterns begin in infants who later develop autism. Studying the mechanisms that underlie these very early brain changes may help scientists develop treatments that could be administered before further changes occur.

The study authors have disclosed no relevant financial relationships.

Nature. Published online February 15, 2017. Abstract

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