Children who are later diagnosed with an autism spectrum disorder have subtle but measurable differences in attention as early as 7 months of age, a new study shows. Infants who went on to be diagnosed with autism are slower to shift their gaze from one object to another, according to the researchers, who identified specific brain circuits that seem to cause the slower response.
The findings point to a problem with “sticky attention,” a phenomenon observed in older children with autism, but not well studied before in babies at risk for autism.
“This is a very exciting study, because the impairments in shifting gaze and attention that we found in 7-month-olds may be a fundamental problem in autism,” said Robert T. Schultz, PhD, director of the Center for Autism Research at CHOP and a co-author on the study.
These findings suggest that 7-month-olds who go on to develop autism show subtle, yet overt, behavioral differences prior to the emergence of autism spectrum disorder. They also implicate a specific neural circuit that may not be functioning as it does in typically developing infants, who show more rapid orienting to visual stimuli.
The results showed that the high-risk infants later found to have ASD were slower to orient or shift their gaze (by approximately 50 milliseconds) than both high-risk-negative and low-risk infants. In addition, visual orienting ability in low-risk infants was uniquely associated with a specific neural circuit in the brain called the splenium of the corpus callosum. This association was not found in infants later classified with ASD.
The study concluded that atypical visual orienting is an early feature of later emerging ASD and is associated with a deficit in a specific neural circuit in the brain.
“These results are another piece of the puzzle in pinpointing the earliest signs of autism,” said Dr. Schultz. “Understanding how autism begins and unfolds in the first years of life will pave the way for more effective interventions and better long-term outcomes for individuals with autism and their families.”
More details of the study are available on the CHOP Research Institute’s website.