ANDIt is common to receive referrals from different professionals in various fields for the diagnosis of autism to others who are dedicated to the same. Many times the request comes explicitly requesting an administration of (Autistic Behavior Observation Scale, second edition), when in reality nothing is known about the patient in question, the path that has been taken so far, their development history, what is their repertoire of behaviors in various contexts, among other significant data.
Is it enough with an ADOS? It is a question that we invite you to keep in mind as you read this article.
Initial considerations for the diagnosis of ASD
The diagnosis of autism comes with great challenges. Although there are cases where the symptomatological manifestation clearly matches the picture described in the international diagnostic manuals (DSM-5 and ICD-11), in many cases it does not. However, there are very diverse conditions for which a differential diagnosis must be made. The most common are cases of children with Specific Language Disorders, social communication disorders, non-verbal learning disorders (neuropsychological condition), epileptic syndromes, intellectual disabilities, among others.
At first, a medical evaluation is necessary in order to rule out any type of difficulties in the area. Once the journey has been made, one way to clarify the diagnosis of ASD is through the use of tests that were created to support it. Currently the most used internationally are the ADOS-2 and the ADI-R. Additionally, developmental evaluation (Bayley 3 up to 48 months, Battele, etc.) and assessment of the level of adaptive behavior (Vineland 2 or 3) are also necessary. It is also important to investigate cognitive aspects (for which the Bayley 3 is valuable), Leitter, WPPSI-IV, WISC IV or V, evaluation of praxias and sensory profile (both generally carried out by occupational therapists) and neurolinguistic evaluation and any other assessment that allows us to know the patient’s performance profile.
What is the ADOS-2 about?
The Observation Scale for the Diagnosis of Autism, 2nd edition (ADOS-2) is a standardized and semi-structured evaluation where communication, social interaction and play or imaginative use of materials are observed in people where suspicions of TORCH.
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This scale has 5 modules (T, 1, 2, 3 and 4), each of which is intended for people with different chronological ages and language levels. It can be used from 12 months to adulthood.
The test is composed of a series of activities that provide standard contexts where the evaluator can observe the presence or absence of social and communicative behaviors relevant to the diagnosis of ASD. As the test is performed, the evaluator records what was observed in the protocol, and then converts the scores using a system of algorithms (Lord et al., 2015).
Due to its complexity, the use of this test requires intensive training by professionals authorized for this purpose, who grant the certification that qualifies other professionals for its clinical administration. If the professional requires authorization to carry out research, they must attend a second instance of training, continuous monitoring and final evaluation to obtain it. It is important that at the time of training, the interested person confirms that they are professionals certified as trainers, otherwise they would not be qualified for clinical administration.
And what about the development story?
One of the most used instruments at an international level that allows greater depth is the ADI-R. It is a clinical interview that allows an in-depth evaluation of patients with suspected ASD. It focuses on behaviors that rarely occur in people who do not present the condition.
During the interview with the parent or caregiver, the professional explores three large areas (language and/or communication, reciprocal social interactions and restricted, repetitive and stereotyped behaviors and interests) through 93 questions. The information collected is subsequently converted into a series of algorithms that allow, through cut-off points in each domain, to identify the presence or absence of characteristics associated with ASD (Rutter, LeuCouteur and Lord, 2006).
In the case of the ADI-R, these algorithms can be used in two ways: for diagnosis where it focuses on the complete developmental history of the individual being evaluated, and a secondary way, called current behavior, where the scores are centered in the behavior observed in recent months. It is very useful for reevaluating treatment plans, evolution, etc.
To use this instrument, clinical certification is required that enables its use. As with the ADOS-2, there is special training by people qualified for this purpose, who in intensive sessions show in detail how to use them.
Encounters and disagreements with regulations
There are places in Argentina where certain organizations responsible for granting documentation that allow access to comprehensive treatment for people with disabilities, and other benefits, require results of the ADOS-2 test from licensed professionals (neurologists, psychiatrists, psychologists, psychopedagogues, speech therapists, etc.) to grant said certificate, when autism is involved. The truth is that the ADOS-2 is not a tool that was intended as an isolated test for the diagnosis of autism. It should be taken as a complement to the diagnostic process.
As the authors of this instrument express, it is only one component within a complete diagnostic evaluation of ASD. The instrument allows collecting information about the patient’s current behavior and is based on a behavioral sample with temporal limitations. The evaluation of ASD, like other disorders, as stated above, requires the evaluation of multiple areas of functioning using various instruments, along with the collection of information from various sources (Lord et. al, 2015).
It is a warning from the authors:
Professionals using the ADOS-2 should remember that the information obtained with it should not be used in isolation to determine an individual’s clinical diagnosis or suitability for certain services. Making a comprehensive clinical diagnosis will require additional information about developmental history and often longer observation, as well as a detailed interview, such as the Autism Diagnostic Interview – Revised (ADI-R; Rutter, Le Couteur). and Lord, 2011) or other interviews or questionnaires directed at caregivers, such as the Social Communication Questionnaire (SCQ; Rutter, Bailey, & Lord, 2005; see also Corsello et al., 2007). It is also necessary to have information about the cognitive and linguistic capacity of the person evaluated to interpret communicative and social behaviors in order to make a clinical diagnosis of ASD (Lord et. al., 2015, p.16-17)
It must be remembered that the manifestations that appear as difficulties in early development can be due to many reasons (epileptic disorders, encephalopathies, sensory alterations, etc.) which must be covered (ruled out by the medical team and other professionals) to address the diagnostic process towards ASD (Fejerman and Grañana, 2015). In any case, there are cases where an evaluation is requested for a case of Secondary or also called syndromic autism, where there is an underlying medical or environmental disorder, autism is secondary to it. Such is the case of, for example, West syndrome, fetal alcohol syndrome, among others. The administration of tests for the diagnosis of autism allows us to build a performance profile in which strengths and weaknesses are identified to include them in a therapeutic plan, adding to the treatment of the underlying disorder.
Returning to the initial question about whether it is enough to obtain the results of the ADOS 2 for the diagnosis of autism, the answer is No. The evaluation instrument, as in all cases, must be incorporated into a diagnostic process where the developmental history, the analysis of the child’s current development with standardized tests, the level of adaptive behavior that is evident, the analysis of of behavior in different contexts where the individual develops. All this information becomes relevant to read the situation and arrive at a diagnosis.
We must remember key concepts, such as false positives and negatives. Diagnostic instruments have an expected margin of error (internal error) that increases the possibility that they can detect or not the presence of alterations that the test aims to measure. There are also external errors (on the part of the evaluator) that need to be considered. This margin of error increases the possibility that it will yield false positives or false negatives, as we have expressed in another article.
Should ADOS-2 be stopped?
According to what we have expressed, the ADOS-2 is a significant tool for the diagnosis and monitoring of people with ASD. It must be used for the purpose for which it was created: to support the diagnostic process, as well as to allow re-evaluation of treatment plans. The correct presentation of the results of this test allows it to be an input for the treatment plans of people with ASD.
We are at a time of growing demand for the administration of these tests, and this is where the role of the professional becomes significant, where ethics must prevail and comply with all the necessary steps to be able to arrive at the diagnosis, which must always be interdisciplinary. It is necessary to remember the ethical weight and responsibility that the administration of these tests acquires as well as the correct interpretation and presentation of the results obtained. This means that it is not enough to report the scores obtained, but rather their interpretation and suggestions must be present to be inserted into treatment plans and others where the individual is inserted.
Bibliographic references:
Fejerman, N. and Grañana, N. (2017). Introduction to Child Neuropsychology. Buenos Aires: Paidós
Gonzalez, DH (2019) ASD, autism, TGD, Asperger? Updating understanding of diagnosis. Recovered from
Leibovich, N. and Schmidt, V. (2008). Reflections on Psychological and Neuropsychological Evaluation. Argentine Journal of Neuropsychology. 12. 21-28
Lord et. to the. (2015)…