Autism Spectrum Disorder Symptoms Detectable at 12 Months

Atypical development in younger siblings of children with autism spectrum disorder can be detected as early as 12 months old.

A study published in the Journal of the American Academy of Child and Adolescent Psychiatry suggests among the siblings with autism spectrum disorder (ASD), atypical development can be detected as early as 12 months of age.

Researchers at the University of California Davis School of Medicine surveyed 294 infant siblings of children with ASD and 116 infant siblings of children with typical development over 36 months. Infants were tested at 6, 12, 18, 24, and 36 months of age using a variety of standard developmental tests for autism symptoms.

At the final visit, participants were classified as ASD, Typical Development (TD), or Non-TD (defined as elevated Autism Diagnostic Observation Schedule (ASOD) score, low Mullen Scale scores, or both).

From the high-risk group, 28% were classified Non-TD at 36 months. This group could not be distinguished from the other groups at 6 months, but by 12 months were significantly different from the low-risk group at 12 months. The Non-TD group showed atypical development in cognitive, motor, language, and social fronts including communication, extreme shyness around strangers, lower levels of eye contact, and delayed pointing.

Seventeen percent of children in the high-risk group developed ASD by 36 months.

“These results demonstrate that features of atypical development, consistent with the broader autism phenotype, are detectable by the first birthday and affect development in multiple domains,” the authors write in the study. “This highlights the necessity for close developmental surveillance of infant siblings of children with ASD, along with implementation of appropriate interventions as needed.”

Sally Ozonoff, PhD, lead author on the study, hopes that the research will give parents and clinicians a chance to intervene earlier to reduce challenges that the families face while raising a child with ASD.