A fixation on geometric patterns may be associated with autism in children as young as 14 months, according to a report published online today that will appear in the January 2011 print issue of Archives of General Psychiatry, one of the JAMA/Archives journals.
"It is undeniable that early treatment can have a significant positive impact on the long-term outcome for children with an autism spectrum disorder," the authors write as background information in the article. "Early treatment, however, generally relies on the age at which a diagnosis can be made, thus pushing early identification research into a category of high public health priority."
Eye tracking technology has potential as a method for characterizing the early features of autism because it can be used to assess individuals at almost any age or level of functioning, the authors note. Karen Pierce, Ph.D., and colleagues at the University of California, San Diego, used this method to study 110 toddlers age 14 to 42 months, 37 with an autism spectrum disorder, 22 with developmental delay and 51 typically developing toddlers. The toddlers were shown a one-minute movie depicting moving geometric patterns on one side of a video monitor and children participating in highly active pursuits, such as yoga and dancing, on the other side.
"Overall, toddlers with an autism spectrum disorder as young as 14 months spent significantly more time fixating on dynamic geometric images than other diagnostic groups," the authors write. Among children with autism, 40 percent spent more than half their viewing time fixated on the geometric images, compared with 1.9 percent of typically developing toddlers and 9 percent of toddlers with developmental delay. Although not all the children with autism showed this preference, 100 percent of the children who spent more than 69 percent of their time fixated on geometric images had an autism spectrum disorder.
Children with an autism spectrum disorder who preferred geometric images had unique patterns of saccades—small, rapid movements of both eyes—as well as fewer saccades overall than the other groups. When the one-minute viewing period was divided into thirds and analyzed, children's preferences were found to remain relatively stable, with an average 15.6 percent change in percentage of preference.
"It is undeniable that eye movements guide learning. What an infant chooses to look at provides images and experiences from which to learn and mature," the authors write. "The impact of reduced social attention in favor of attention to geometry at such an early age in development can only be surmised, but it is thus no surprise that functional magnetic resonance imaging studies of older children and adults with autism often report weak or absent functional activity in brain regions involved in social processing, such as the fusiform, medial frontal lobes, amygdala and cingulate."
The results suggest that some infants at risk for an autism spectrum disorder begin life with atypical preferences for geometric repetition. "We believe that it may be easy to capture this preference using relatively inexpensive techniques in mainstream clinical settings, such as a pediatrician's office. Furthermore, we also believe that infants identified as exhibiting preferences for geometric repetition are excellent candidates for further developmental evaluation and possible early treatment," the authors conclude.
(Arch Gen Psychiatry. Published online September 6, 2010. doi:10.1001/archgenpsychiatry.2010.113. Available pre-embargo to the media at www.jamamedia.org.)
Editor's Note: This work was funded by a National Institute of Mental Health grant and a National Institute of Mental Health Autism Center of Excellence grant. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.