Autism Speaks Official Blog

We studied over 100 infants who have an older sibling with ASD and therefore have a higher-than-usual risk for developing autism. From this initial group, we focused on the 25 high-risk infants who later developed ASD. We compared them to 25 infants who do not have an older sibling with ASD who had typical development. Both groups of infants were followed from age 6 months through 3 years and tested with a collection of age-appropriate social and cognitive tests by a trained examiner who did not know if the child was in the high or low risk group.  Several important findings emerged when we examined the children’s social interaction and cognitive development.

At 6 months, nearly all children showed a rich repertoire of engaging social behaviors. In fact, children who later went on to be diagnosed with an ASD were actually more socially engaged at 6 months than those who went on to have typical development. The pattern changed dramatically by 12 months.  As a group, children who later developed ASD showed less eye contact, social smiling, vocalizations, and other signs of engagement at 12 months than they did at 6 months. This is evidence of an early, but slow, loss of skills and was a pattern we observed in about three quarters of the infants who developed ASD.

Interestingly, most parents did not notice or report this decline in their infant’s skills as it was occurring. When explicitly asked by the researchers, parents did not report to us that their child was regressing.  It could be that these early changes we were observing were not easily observable outside of the controlled testing environment of the lab and that many other things are happening during this developmental window, such as learning to walk, that capture parents’ attention. These results suggest that closer monitoring of high-risk infants is warranted so that, if needed, interventions can begin as early as possible. These results also tell us that it is very important to screen for autism multiple times during the first years of life, since the emergence of symptoms can be so gradual it may be hard to detect in a single visit. 

No one study provides the answers to all our questions. The aim of this study was to identify early indicators of autism for better diagnosis. To that end, we identified a relatively common pattern of a slow loss of skills late in the first year of life in infants who later develop ASD.  Studies like these enhance our ability to identify children at risk at earlier ages and offer services to those in need, when they could be most beneficial. Early intervention offers great promise for improving the outcomes of any child diagnosed with ASD, especially when initiated as early as possible.

Our study was not designed to address the causes for the loss of skills although that is, of course, a very important question. Most babies have small ups and downs in their development that aren’t necessarily anything to worry about. However, if you begin to wonder if your child is becoming less social or less communicative over time (for example, less smiling, or fewer head turns when his name is called), then this is something important to bring up with your pediatrician, especially if you already have a child on the spectrum.

Autism Speaks’ website offers information about early signs of autism in a video glossary, which concerned parents may find useful as well

Reference:  Ozonoff S, Iosif A-M, Baguio F, Cook IC, Hill MM, Hutman T, Rogers SJ, Rozga A, Sangha S, Sigman M, Steinfeld MB, Young GS. (2010) A prospective study of the early behavioral signs of autism spectrum disorder. J. Am. Acad. Child Adolesc. Psychiatry. 49(3): 258-268.

This guest post is written by Sally Ozonoff, Ph.D. Dr. Ozonoff’s research focuses on very young children with autism, early identification, and autistic regression. She is a professor and vice chair at UC Davis’ MIND Institute, as well as a practicing clinical psychologist. She has written over a hundred peer-reviewed publications and chapters, as well as three books, on autism.