While kids (and their parents) were making Valentine’s Day cards last week, a paper was released in the prestigious journal, Nature that garnered some attention in the media.
The paper reported the results of a very large, longitudinal imaging study of younger infant siblings of children with autism. The study is the result of several years of work by a research network, called Infant Brain Imaging Study (IBIS), which is directed by Joe Piven at University of North Carolina, and includes several scientists around the country, including scientists here in Seattle at the University of Washington.
The scientists first used magnetic resonance imaging (MRI) to scan the brains of almost 150 infants, 106 of which have an older sibling with ASD. These infant siblings are 20 times more likely to get an ASD diagnosis than a child in the general population. The scientists measured brain volume and surface area using MRI when the children were 6, 12, and 24 months of age and conducted a diagnostic evaluation when the children turned 2 years old.
Of the 106 infant siblings, 15 received an ASD diagnosis at 2 years old. Those that were diagnosed with ASD had brain surface area that grew much faster between 6 and 12 months, then had overall brain volumes that increased faster between 12 and 24 months of age.
Using complicated statistics, called machine learning, they then looked at brain scans collected from additional baby siblings for whom the diagnosis was known. They then looked back at the scans collected from those baby siblings at 6, 12 and 24 months and used these brain growth patterns to classify which infants would have ASD and which would not. The statistical algorithm correctly predicted an ASD diagnosis for 81% of the infant siblings.
The study provides insight into neural changes that seem to be occurring in young children who go on to develop ASD. However, there isn’t any evidence to suggest this pattern of growth applies to all children who develop ASD. So, for parents, it’s important to know that the predictions were based on data from infant siblings of children with ASD. As such, it’s unclear what the implications are for families without a child with ASD already.
Finally, using brain scans as a screening tool for ASD is unlikely to be adopted given the practical challenges of using MRI with infants. In fact, only 1/3 of the infants in the IBIS study were able to complete the brain scans at all 3 ages.
Science moves forward incrementally. This study is an important step. The next step is to more clearly understand this rapid-growth phenomena.