The protocol consists of a series of structured and semi-structured tasks that involve social interaction between the examiner and the person under assessment.
Research-determined cut-offs identify the potential diagnosis of autism spectrum disorder, allowing a standardized assessment of autistic symptoms.
The Autism Diagnostic Interview-Revised (ADI-R), a companion instrument, is a structured interview conducted with the parents of the referred individual to cover the subject's full developmental history.
[1] The original ADOS was created by Catherine Lord, Michael Rutter, Pamela C. DiLavore and Susan Risi in 1989.
During this time, the examiner provides a series of opportunities for the subject to show social and communication behaviors relevant to the diagnosis of autism.
The ADOS should not be used for formal diagnosis with individuals who are blind, deaf, or otherwise seriously impaired by sensory or motor disorders, such as cerebral palsy or muscular dystrophy.
Activities marked by an asterisk are optional: The social communication difficulties that the ADOS and ADOS-2 seek to measure are not unique to ASD; there is a heightened risk of false positives in individuals with other psychological disorders.
[15] False positives have also been found in school-age subjects who have high anxiety or trauma-related disorders; in these cases, the ADOS-2 scores related to repetitive and restrictive behaviors (RRB) are usually lower than typical for ASD.
One included study examined the additive sensitivity and specificity of the ADOS used in combination with the ADI-R; that study found an 11% improvement in specificity (compared to ADOS alone) at the cost of a 14% reduction in sensitivity; however, due to overlapping confidence intervals, that result could not be considered statistically significant.