Second only to mental retardation as the most common developmental disability, autism forms part of a spectrum of related disorders referred to as the autism spectrum disorders (ASDs). Although symptoms can range from mild to severe, those affected typically exhibit severe impairments in social interaction and communication, and engage in repetitive, solitary activities.
The complex nature of the disorder makes it difficult to diagnose. In the absence of any biological marker, clinicians have been typically forced to rely on parental reports, home videos and direct observations of behavior, using standardized tools like the Checklist for Autism in Toddlers (CHAT). But these tools were designed for children 18 months and older; there has been no instrument to measure autistic behaviors in young infants.
So the Canadian researchers designed their own. Led by Susan Bryson, Craig Chair in Autism Research at the IWK Health Centre/Dalhousie University, and co-lead investigator for the study, they developed the Autism Observation Scale for Infants (AOSI). The scale maps the development of infants as young as six months against 16 specific risk markers for autism, including such behaviors such as not smiling in response to the smiles of others or not responding when one's name is called.
"The predictive power of these markers is remarkable", says Dr. Zwaigenbaum. "We are finding that within this high-risk group of siblings, almost all of the children who are diagnosed with autism by age two years have seven or more of these markers by the time they are a year old."
The researchers found that even at six months of age there were certain behaviors that distinguished those siblings later diagnosed with autism from other siblings. These included a passive temperament an
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Contact: Veronica McGuire
vmcguir@mcmaster.ca
905 525-9140 22169
McMaster University
28-Apr-2005