Diagnosing autism in a clinical sample of adults with intellectual disabilities: how useful are the ADOS and the ADI-R?
ADOS is great at catching autism in adults with ID but also over-diagnoses, so pair it with ADI-R and raise the cut-off.
01Research in Context
What this study did
The team asked: can the ADOS and ADI-R spot autism in adults who also have intellectual disability?
They tested the adults with ID already seen at a Dutch clinic. Each adult got both tools plus expert review.
They tracked how often each test called the same person autistic and how often the experts agreed.
What they found
ADOS caught almost every true case (high sensitivity) but also flagged many non-autistic adults (low specificity).
ADI-R missed more true cases (lower sensitivity) but rarely gave a false positive (high specificity).
Staff said ADI-R took too long and needed more records; ADOS was faster but sometimes over-counted.
How this fits with other research
Berument et al. (2005) ran a smaller pilot with the PL-ADOS in severe ID and got cleaner numbers. Tanja’s bigger sample shows the regular ADOS is more sensitive but also more over-inclusive—an update, not a clash.
Sasson et al. (2022) later tested deaf adults with ID using different screeners. They also had to tweak cut-offs and wording. The pattern is the same: standard tools work, but you must adapt for sensory or cognitive limits.
Rojahn et al. (2012) found the SRS over-flagged kids much like the ADOS over-flagged these adults. Two tools, two ages, same lesson: high sensitivity alone can flood you with false positives.
Why it matters
If you assess adults with ID, use ADOS first to avoid missing autism, then back it with ADI-R or record review to weed out false positives. Shorten ADI-R items, allow proxy answers, and set a higher ADOS cut-off. These small fixes keep the tools sharp and save you time.
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02At a glance
03Original abstract
Intellectual disability (ID) and autism spectrum disorder (ASD) are frequently co-occurring conditions. Carefully diagnosing ASD in individuals with ID would allow for more tailored clinical interventions that would improve mental health and quality of life. In this study, we evaluated the psychometric properties of the Autism Diagnostic Observation Schedule (ADOS) and the Autism Diagnostic Interview-Revised (ADI-R) in a clinical sample of 79 adults with ID who were suspected of also having ASD. In the testable cases (68%), the ADOS was over-inclusive (specificity 45%) but highly sensitive (100%) of ASD. In the ADI-R, the feasibility was 37%, with a sensitivity of 88% and a specificity of 80%. Previously proposed adaptations of the ADOS algorithm were evaluated, and new items and tasks were suggested. The ADOS and the ADI-R were found to be valuable diagnostic tools for adults with ID. Adjustments of the setting and the tasks may further improve their feasibility and specificity.
Research in developmental disabilities, 2013 · doi:10.1016/j.ridd.2013.01.028