Diagnosing autism in people with multiple disabilities: introducing a new instrument

Aim: Currently, there are no instruments that can validly diagnose autism spectrum disorder (ASD) in people that have an intellectual disability (ID) with additional sensory disabilities. People with these disabilities show ASD typical behaviour regardless of the presence of ASD. This makes diagnosing ASD in this group difficult. The aim of the current study was to design a new diagnostic instrument that can accurately diagnose ASD in people with intellectual and sensory disabilities. Method: Observation of Autism in people with Sensory and Intellectual Shortcomings (OASIS) is a semi-standardised observational instrument that assesses the presence of ASD by evoking ASD typical behaviours in a playful setting. Behaviours are scored afterwards through video recordings. A total of 60 participants with multiple impairments were tested. Results: Using expert consensus as a gold standard for presence of ASD, a pilot study showed that OASIS can successfully differentiate people with and without ASD when they have multiple disabilities and inter-rater reliability, internal consistency and several measures of validity were good to excellent. These results and results and preliminary results of a larger sample will be discussed. Conclusion: OASIS is a new tool to diagnose ASD in people with sensory and ID reliably and validly