ADOS - Autism Diagnostic Observation Schedule

The Autism Diagnostic Observation Schedule (ADOS) is a semi-structured assessment for diagnosing autism. It consists of various social and play-based activities designed to observe behaviors related to autism. [See posts on other Screening/Diagnostic Measures]

Limitations of ADOS as a dx tool

1. Not a Standalone Diagnostic Tool: It is intended to be part of a comprehensive evaluation, which should also include other assessments and detailed developmental history.
2. Snapshot in Time: ADOS provides a snapshot of an individual's behavior during the time of the assessment, which may not capture the full range of behavior or abilities.
3. Limited Scope: It primarily focuses on two areas: social interaction and communication, and restricted/repetitive behaviors. Other aspects of autism, such as sensory issues or co-occurring conditions, are not part of the primary scoring system.
4. Language and Age Constraints: While ADOS offers different modules for different developmental stages and language abilities, it may not be entirely suitable for all individuals, particularly those with complex profiles or co-occurring conditions.
5. Requires Specialized Training: to ensure accurate administration and interpretation of the results. This requirement can limit its accessibility and use.
6. Culture and Context: The ADOS was developed in English-speaking countries and may not fully account for cultural differences in behavior and communication. Translated versions are available, but they may not capture all nuances.
7. Reliability of Diagnosis over Time: Some studies have questioned the reliability of the ADOS over time, especially in younger children, where symptoms and behaviors can change significantly as the child grows and develops.

ADOS has four modules:

Each module is designed for different developmental and language levels, ranging from non-speaking children to fluent-speaking adults. The professional selects the appropriate module based on the individual's expressive language level and chronological age.

• Module 1: This module is intended for children who do not consistently use phrase speech. This could be children who are nonverbal or only use single words. Activities are simple and often play-based, designed to elicit social interaction, communication, and repetitive behaviors.
• Module 2: This module is used with individuals of any age who use phrase speech but are not verbally fluent. These individuals may have some language abilities but often have irregularities in conversation and narrative generation.
• Module 3: This module is intended for verbally fluent children and young adolescents. It involves more complex and interactive activities, including a "make-believe" play task, conversation, and storytelling.
• Module 4: This module is for verbally fluent older adolescents and adults. It comprises activities appropriate for this age range and verbal fluency, such as a discussion of life experiences, understanding of emotions, and creation of a short story.

I mourn the fact that in this measure the four modules and the activities in them are  based on the notion  that "ability to speak" = "cognition". This is harmful in terms of expectations for that child. Speaking ability and cognition are changeable constructs. If a clinician themselves are dismissive of that autistic, so too will educators in terms of expectations, inclusion and other opportunities - this has lifelong consequences. That child is basically doomed to never "improve" as professionals are told the message of "why bother?"

Aspects measured by ADOS include:

• Communication: This assesses both verbal and non-verbal communication skills, such as the individual's ability to make conversation, use gestures, or share enjoyment.
• Social Interaction: This measures the individual's ability to engage with others, including initiating interactions, responding to social cues, and building relationships.
• Play: This measures the individual's ability to engage in imaginative play and shared enjoyment.
• Restricted and Repetitive Behaviors: This assesses common symptoms of autism, such as repetitive movements, routines, or interests.

Scoring & Interpretation

Each behavior is scored, and scores are combined to create a total that is compared to a threshold for autism. The higher the score, the more likely the individual meets criteria for an autism spectrum disorder.

During the ADOS assessment, behaviors are observed and coded for various tasks. These codes are scored from 0 to 3, (0: No evidence of atypical behavior related to autism; 2: Definite and marked atypical behavior 3: Significant atypical behavior)

The codes are used to calculate scores in two main areas:

1. Social Affect (SA): This captures social-communication challenges, such as eye contact, facial expressions, shared enjoyment, response to joint attention, gestures, and quality of social overtures.
2. Restricted and Repetitive Behaviors (RRB): This captures behaviors like sensory interests, hand and finger mannerisms, and unusual sensory interests.

These scores for individual items are then added together to get a total score in each domain for the ADOS algorithm. The ADOS-2 manual provides specific cut-offs for each module that help interpret the SA, RRB, and Total scores to assist in diagnosis:

• A score below the autism cut-off in both SA and RRB likely indicates that the individual does not have autism.
• A score at or above the autism cut-off in either SA or RRB but below the autism cut-off may indicate that the individual has less-severe autism. 
• A score at or above the Autism cut-off in both SA and RRB likely indicates that the individual has more severe autism. 

The specific cut-off scores depend on the module used and can be found in the ADOS-2 manual.

Lastly, the "comparison score" provides an interpretation of severity that is more consistent across modules and developmental levels. This score ranges from 1 (minimal-to-no evidence of autism symptoms) to 10 (a high level of autism symptoms).

History of ADOS:

The ADOS was developed by Catherine Lord, Michael Rutter, and colleagues as a direct observational measure.  The first edition was published in 1989, with a second edition, ADOS-2 in 2012.

ADOS  is typically used in conjunction with other assessment tools, like the Autism Diagnostic Interview-Revised (ADI-R), and a comprehensive developmental history and clinical observation.

Reference:
Lord, C., Rutter, M., DiLavore, P. C., Risi, S., Gotham, K., & Bishop, S. (2012). Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) Manual (Part I): Modules 1–4. Torrance, CA: Western Psychological Services