We have developed our ‘Getting to grips with SLT’ blog series to help families and school clients to learn more about the specialist support that we can provide. This blog is all about the ADOS assessment tool.

What is an ADOS?

Perhaps the most common question I get asked is “Do you think my child has autism?”. It is clearly one of the major concerns of a parent who has a child with communication difficulties. Now, autism, along with its associated disorders (Autism Spectrum Disorders ASD), is actually relatively common. In the U.K., approximately 1% of the population known to have some form of the condition.

Those looking into what assessment of Autism Spectrum Disorder (ASD) involves and anyone working or researching in this field are likely to come across people referring to ‘the ADOS’. This is an acronym short for ‘Autism Diagnostic Observation Schedule’, which is basically an assessment tool that is used by clinicians and researchers to help identify whether someone meets criteria for a diagnosis of autism, or is presenting with features of ASD. The tool was originally created by autism experts Catherine Lord, Michael Rutter, Pamela Di Lavore and Susan Risi in 1989 and a revised second edition (ADOS-2) with an additional Toddler Module was released in 2012.

Because it is one of the few standardised assessments for autism it has been referred to as one of the ‘gold standard’ assessments and in the U.K. is recognised by the National Institute of Health and Care Excellence (NICE) as one of the key diagnostic assessment tools.

Some people think that the ADOS is the test for autism that you either pass or fail. It isn’t. The ADOS is only one part of the whole assessment process. There are other pieces of critical information that are needed to make a judgement as to whether a person meets the criteria for autism or not. These
include background information, family history, medical information, speech, language and communication, general learning abilities and observations in social situations. It’s recommended that this information is collected from several professionals including clinical psychologists, speech and language therapists, medical practitioners as appropriate such as paediatricians or psychiatrists in order to build a holistic picture of the person over time in terms of how they react and respond in different circumstances.

So, what actually is an ADOS assessment?

The ADOS is an observational assessment tool; it involves direct observation of the person being assessed, as opposed to information given by other people. This usually means the person being assessed either attending a clinic for a prearranged appointment, or in some circumstances someone trained in using the ADOS coming out to visit the individual being assessed at home, school or another appropriate place. For very young children the parents or carers are asked to be in the session and will be asked to participate in some of the activities. Usually, the person would be in the room with the assessors by themselves with the parents or carers waiting outside, usually in a waiting room. Plenty of care is taken beforehand to explain what will happen in the assessment to put everyone at ease.

The ADOS tends to involve two practitioners who have undertaken the accredited ADOS training, carrying out the assessment, although it can be done with just one. A second person is recommended as a ‘second pair of eyes’ to observe anything they may have missed whilst they are administering the assessment and it can also be helpful for someone else to take notes to aid rating/scoring the observations afterwards. Often the assessment is videoed to allow the assessors the ability to look back and check if their observations have been accurate.

So is it a test?

Many people worry about what happens if they get the answers wrong. The ADOS is actually a semistructured set of tasks, activities and interactions that aims to elicit behaviours and skills that are associated with ASD, as the observational part of a wider assessment process. It takes about 45 mins to one hour. In the latest version of the ADOS, the second edition (ADOS-2) published in 2012, there are five different ‘modules’, each containing a set of semi-structured tasks, activities and discussion topics which take into account what we would expect at different stages of development. So, it is play-based for younger children and for those who are older, is focused more on a chat to get to know the person and what they think about things. There are no ‘right or wrong answers’. Most find it actually quite enjoyable.

Immediately following the assessment, the observations of the person and how they responded and approached the different tasks needs are rated using the ADOS scoring schedule. As part of this rating the assessors are evaluating specific aspects of the individual’s social interaction, language and communication, repetitive and stereotyped behaviours, and any sensory issues. They are given a numerical rating according to whether the person displayed typical responses and behaviours, or whether they presented as atypical or having a degree of difficulty.
The scores allow the assessors to work out whether the behaviours and responses they saw during the ADOS assessment correspond to a ‘high’ level of ASD features and thus a high probability of meeting criteria for a diagnosis of ASD, or a ‘low’ level of ASD features and a low probability of meeting
diagnostic criteria.

This information is taken into consideration as part of the entire assessment process and is clearly documented and explained in a follow up interview with parents or with the adult concerned as well as in a written report. What is sometimes confusing for people is that having a high score on the ADOS does not automatically mean the person will receive a diagnosis of autism. This is because there could be other reasons that account for the high score. This could be because of learning difficulties, high levels of anxiety, specific language difficulties to name a few. Sometimes the information can be contradictory or unclear. Other times, it maybe that the assessors ask to see what happens over time as the child matures. As practitioners, we want to make sure that if we are giving such important information to people that we are thoroughly confident in our decision. For this reason, the ADOS can be repeated after an appropriate time delay.

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