Navigating the autism diagnostic process can be challenging. Unfamiliar tools and inconsistent information can create confusion. In this blog, you can read about one of the most common tools used in the autism diagnostic process – the Autism Diagnostic Observation Schedule (ADOS), including:
- What is the ADOS?
- What does an ADOS assessment involve?
- When should the ADOS be used? … and when should the ADOS not be used?
- Misuse or misinterpretation of the ADOS
- How can the ADOS strengthen the diagnostic process?
What is the ADOS?
Autism is diagnosed based on the observation and reporting of a range of characteristics and behaviours in a child or adult. A trained clinician gathers information and makes a judgement whether the characteristics and behaviours observed or reported match to the autism diagnostic criteria. The process is subjective – even with the best tools and highly skilled clinicians, it involves some grey areas of interpretation.
A face-to-face interaction with the individual being evaluated is a necessary step in the autism diagnostic process. But it is important to note that how a child or adult might act during a face-to-face assessment is strongly influenced by their immediate environment, like the toys/materials they have access to, the instructions they are given or the behaviour of the assessor (for example, how social or chatty the assessor is themselves).
Researchers wanted to create a tool that would help make the process of gathering observations more consistent and reliable across assessors and environments, so they developed the Autism Diagnostic Observation Schedule (ADOS). The ADOS is a semi-structured assessment tool that helps to promote reliability in autism diagnostic assessments by providing a consistent structure, materials and assessor training. The most current version of the ADOS is the Second Edition (ADOS-2; Lord at al., 2012).
What does an ADOS assessment involve?
While the ADOS is semi-structured, it also allows for some flexibility so that the assessment is suitable and engaging for a diverse range of children and adults. What an ADOS will look like varies depending on how old the individual is and how much verbal language they use to communicate.
For young children or those with minimal verbal language, the assessment looks like simple interactive play. For older children with fluent communication, the assessment looks like a mix of play, table activities, chat and interview questions. For older teens and adults, the ADOS consists of a few table activities, but mostly conversation and interview interactions.
The ADOS takes around 40-60 minutes to complete. It is a face-to-face assessment that is administered by a trained clinician, usually in a clinical setting. The ADOS-2 cannot be reliably administered via telehealth. For young children, a caregiver is required to be in the room for the entire assessment. For older children, teens, and adults, caregivers or other family members are not present for the assessment.
When should the ADOS be used? … and when should the ADOS not be used?
The ADOS is often referred to as being a ‘gold-standard’ diagnostic tool. This is because it has been shown in extensive research to be a valid and reliable tool for identifying autistic individuals (Gotham et al., 2008; Hong, 2022; Hus Bal & Lord, 2014; Lebersfeld et al., 2021). When completing an autism diagnostic evaluation, a clinician trained in using the ADOS might consider using the tool to help support their clinical decision-making.
But an ADOS may not be suitable for use in every diagnostic evaluation, and so a clinician may appropriately choose not to use the tool in some circumstances. For example, the ADOS may not be suitable for the assessment of individuals with specific or complex co-occurring conditions, such as vision-impairment or significant motor differences. The ADOS cannot be validly used with an interpreter and so cannot be used when the assessor and the individual being assessed speak different languages. An appropriately trained clinician will be able to determine when to use or not use the ADOS and give sound reasoning around their choice.
Misuse or misinterpretation of the ADOS
An autism diagnosis should never be based on the results of one tool alone. The ADOS can be a great tool for supporting decision-making in the diagnostic process, but it should not be the only source of information. A clinician’s broader knowledge, skills and training remain key to determining an accurate diagnostic outcome from any diagnostic evaluation (Bishop & Lord, 2023). It is a misuse of the ADOS to base a diagnostic outcome on the ADOS alone.
How can an ADOS strengthen the diagnostic process?
When used and interpreted correctly the ADOS can be an invaluable tool for supporting a diagnostic evaluation. It can be administered in such as way so that it feels like a fun, play based interaction with young children, or an engaging conversation with teens and adults – all while gathering observations to inform the diagnostic evaluation. The process of completing an ADOS can provide clinicians and parents reassurance that observations have been systematically gathered, and when used by skilled clinicians in combination with other tools, can contribute to a robust diagnostic evaluation based on research evidence.
This blog was written by Gracen Murphy and Sarah Pillar. Gracen is a Speech Pathologist at CliniKids and Sarah is the Research Development Manager at CliniKids. Sarah is also a Speech Pathologist and ADOS-2 Trainer.
CliniKids runs ADOS-2 training for clinicians. For more information, dates, eligibility requirements and pricing, visit the Professional Training page.
References
Bishop, S. L., & Lord, C. (2023). Commentary: Best practices and processes for assessment of autism spectrum disorder – the intended role of standardized diagnostic instruments. Journal of Child Psychology and Psychiatry, 64(5), 834–838. https://doi.org/10.1111/jcpp.13802
Gotham, K., Risi, S., Dawson, G., Tager-Flusberg, H., Joseph, R., Carter, A., ... & Lord, C. (2008). A replication of the Autism Diagnostic Observation Schedule (ADOS) revised algorithms. Journal of the American Academy of Child & Adolescent Psychiatry, 47(6), 642-651.
Hong, J. S., Singh, V., Kalb, L., Reetzke, R., Ludwig, N. N., Pfeiffer, D., Holingue, C., Menon, D., Lu, Q., Ashkar, A., & Landa, R. (2022). Replication study for ADOS‐2 cut‐offs to assist evaluation of autism spectrum disorder. Autism Research, 15(11), 2181–2191. https://doi.org/10.1002/aur.2801
Hus, V., & Lord, C. (2014). The autism diagnostic observation schedule, module 4: revised algorithm and standardized severity scores. Journal of autism and developmental disorders, 44, 1996-2012.
Lebersfeld, J. B., Swanson, M., Clesi, C. D., & O’Kelley, S. E. (2021). Systematic review and meta-analysis of the clinical utility of the ADOS-2 and the ADI-R in diagnosing autism spectrum disorders in children. Journal of Autism and Developmental Disorders, 1-14.
Lord, C., Luyster, R.J., Gotham, K., & Guthrie, W. (2012). Autism diagnostic observation schedule, second edition (ADOS-2) manual. Torrance, CA: Western Psychological Services.