Reference Work Entry

Comprehensive Guide to Autism

pp 299-310

Autism Observation Scale for Infants

  • Susan E. BrysonAffiliated withAutism Research Centre, IWK Health Centre Email author 
  • , Lonnie ZwaigenbaumAffiliated withAutism Research Centre, Glenrose Rehabilitation Hospital


In this chapter, we describe the Autism Observation Scale for Infants (AOSI) and its development. We also provide an overview of research using the AOSI, as well as updated data on its predictive validity. While findings indicate that the AOSI provides a reliable means of detecting and monitoring signs of ASD in infants aged 6–18 months, inadequate sensitivity of the scale precludes its clinical use as a screen for ASD risk. The AOSI appears particularly insensitive to highly verbal children who are more mildly affected by autism but nonetheless meet criteria for an ASD diagnosis at 3 years of age. On the other hand, the AOSI may be useful in identifying the children most severely affected by autism and thus most in need of very early intervention.