Diagnostic tests for autism spectrum disorder (ASD) in preschool children

This new Cochrane DTA Review assessed the accuracy of tools for diagnosing autism spectrum disorder (ASD) in preschool children. The review authors wanted to know which of the most commonly used tools is most accurate for diagnosing ASD in preschool children. 

The Cochrane researchers reviewed 13 publications on six tests: Autism Diagnostic Interview-Revised (ADI-R); Gilliam Autism Rating Scale (GARS); Diagnostic Interview for Social and Communication Disorder (DISCO); Developmental, Dimensional, and Diagnostic Interview (3di); Autism Diagnostic Observation Schedule (ADOS); and Childhood Autism Rating Scale (CARS). Results were only available for three tools: ADOS (Modules 1 and 2), CARS, and ADI-R.

The researchers included 21 sets of analyses conducted on 2900 children younger than six years of age, or children with a mean age less than six years, with language difficulties, developmental delay, intellectual disability, or a mental health problem.  The prevalence of ASD for children in the analyses was 74%.  Studies were carried out in Australia, Canada, India, the Netherlands, UK, and the USA. 

The review authors concluded that the: ADOS is best for not missing children who have ASD and is similar to CARS and ADI-R in not falsely diagnosing ASD in a child who does not have ASD. ADOS has accepatble accuracy in populations with a high prevalence of ASD. However, overdiagnosis is likely if the tool is used in populations with a lower prevalence of ASD. This finding supports current recommended practice of ASD diagnostic tools to be used as part of a multi-disciplinary assessment, rather than as stand-alone diagnostic intstruments.

Read the full review here