The Infant Sibling (IBIS) Network studies infants and toddlers born into families where there is already an older sibling with Autism Spectrum Disorder (ASD). This network aims to understand the earliest manifestations of ASD in both brain and behavior. To do so, the study uses MRI and detailed clinical assessments to compare infants and toddlers from families with ASD to those without a family history of ASD. CAR is one of the primary centers in the IBIS network, an NIH Autism Center of Excellence.
A new IBIS study used eye tracking to measure how and when infants shifted their eye gaze to different objects in front of them. We found that 7-month-olds who went on to develop ASD were slower to shift their attention from one object to another when compared to 7‐month‐olds who did not develop ASD. Slow eye gaze shifts are believed to make it more difficult for the infant to learn about their environment, placing them at risk for developmental delays.
In this study, slower eye gaze shifts also correlated with the maturity of one part of the brain – the “corpus callosum.” The corpus callosum is the largest group of fibers connecting the right and left halves of the brain. Sharing of information between both halves of the brain helps with shifting of eye gaze and attention. Using MRI, we were able to show that the corpus callosum was immature in 7-month-old infants who later were diagnosed with ASD. This finding is consistent with other MRI studies in older youth with ASD that show abnormalities in the brain’s “wiring.” However, prior to our IBIS studies it was not known to occur at such a young age.
This research is important because it pinpoints a specific brain circuit that is developing atypically very early in life, prior to the child showing outward signs and symptoms of ASD. This early marker for ASD within the biology of the child (a “biomarker”) could be very helpful for earlier detection of ASD when combined with other biomarkers. All early detection markers are important for guiding the development of early treatments. Thus, our team is hopeful that these findings may lead to earlier diagnoses, intervention, and subsequent improved outcomes for individuals with ASD.
In addition to the Center for Autism Research at CHOP, other institutions that took part in the study include The University of North Carolina, University of Utah, Washington University in St. Louis, University of Washington, McGill University, and the University of Alberta. The National Institutes of Health, Autism Speaks, and the Simons Foundation Autism Research Initiative fund this research.
Source: Elison, J.T., Paterson, S.J., Wolff, J.J., Reznick, J.S., Sasson, N.J., Gu, H., Dager, S.R., Estes, A.M., Evans, A.C., Gerig, G., Hazlett, H.C., Schultz, R.T., Styner, M., Zwaigenbaum, L., Piven, J., & IBIS Network. (2013). White matter microstructure and atypical visual orienting in 7-month-olds at risk for autism. The American Journal of Psychiatry, 170(8), 899–908. PMID: 23511344