assess autism in children, adolescents, and adults
The Autism Diagnostic Observation Schedule (ADOS) is a standardized diagnostic test for assessing
autism spectrum disorder. The protocol consists of a series of structured and semi-structured tasks that involve social interaction between the examiner and the person under assessment. The examiner observes and identifies aspects of the subject's behavior, assigns these to predetermined categories, and combines these categorized observations to produce quantitative scores for analysis. Research-determined cut-offs identify the potential diagnosis of autism spectrum disorder, allowing a standardized assessment of autistic symptoms.
The
Autism Diagnostic Interview-Revised (ADI-R), a companion instrument, is a structured interview conducted with the parents of the referred individual to cover the subject's full developmental history. The ADI-R has lower sensitivity but similar specificity to the ADOS.
Responding to the need for diagnostic tools for autism in younger children, researchers developed the Pre-Linguistic Autism Diagnostic Observation Schedule (PL-ADOS).[2] The content of the activities, as well as the general format, were adapted to rely less on conversation.
ADOS-G
In 2000, Lord and her colleagues introduced the ADOS-Generic (ADOS-G) as a means to assess a broader developmental range of individuals. The ADOS-G introduced a module format, allowing for different protocols to be used depending on developmental and language factors.[3] It became commercially available in 2001 through Western Psychological Services.[4]
ADOS-2
A second edition was published in 2012 to include updated norms, improved algorithms for Modules 1 to 3, and a new Toddler Module (T) that facilitates assessment in children ages 12 to 30 months.[5][6] Changes were also made to the algorithm to report on domains more in line with the recent changes to diagnostic criteria in the
DSM-5. Whereas the ADOS-G determined social, communication, and social-communication domains, the ADOS-2 combined these domains to represent social affect, and added a new domain to assess restrictive and repetitive behaviors (RRB).
Method
The ADOS consists of a series of structured and semi-structured tasks that generally takes 30-60 minutes to administer. During this time, the examiner provides a series of opportunities for the subject to show social and communication behaviors relevant to the diagnosis of autism.[4] Each subject is administered activities from the module that corresponds to their developmental and language level. The ADOS should not be used for formal diagnosis with individuals who are
blind,
deaf, or otherwise seriously impaired by sensory or motor disorders, such as
cerebral palsy or
muscular dystrophy.
Following task administration and observation coding, a scoring algorithm classifies the individual with autism, autism spectrum disorder, or non-spectrum disorder. The toddler module algorithm yields a "range of concern" rather than a definite classification.[7]
Modules
Toddler module
The toddler module is appropriate for children 12–30 months who use little to no phrase speech. Because social communication and behavioral patterns can be highly variable in the first 2 years of life, the toddler module is typically used to identify areas for continued monitoring rather than to provide a definite diagnosis. The toddler must be able to walk independently.[8] This module consists of eleven primary activities:[7]
Free play
Blocking toy play
Response to name
Bubble play
Anticipation of a routine with objects
Response to joint attention
Responsive social smile
Anticipation of social routine
Functional and symbolic imitation
Bath time
Snack
Module 1
Module 1 is appropriate for children 31 months and older who use little or no phrase speech. This module consists of ten activities:[5]
Free play
Response to name
Response to joint attention
Bubble play
Anticipation of a routine with objects
Responsive social smile
Anticipation of a social routine
Functional and symbolic imitation
Birthday party
Snack
Module 2
Module 2 is appropriate for children six years old or younger who speak in phrases but have not yet developed fluent verbal language. This module consists of fourteen activities:[5]
Construction task
Response to name
Make-believe play
Joint interactive play
Conversation
Response to joint attention
Demonstration task
Description of a picture
Telling a story from a book
Free play
Birthday party
Snack
Anticipation of a routine with objects
Bubble play
Module 3
Module 3 is appropriate for children or young adolescents who are verbally fluent. This module consists of fourteen activities:[5]
Construction task
Make-believe play
Joint interactive play
Demonstration task
Description of a picture
Telling a story from a book
Cartoons
Conversation and reporting
Emotions
Social difficulties and annoyance
Break
Friends, relationships, and marriage
Loneliness
Creating a story
Module 4
Module 4 is appropriate for older adolescents and adults. While similar to module 3, module 4 relies more heavily on questions and verbal responses rather than non-verbal actions observed during play. This module consists of ten to fifteen activities. Activities marked by an asterisk are optional:
Construction task*
Telling a story from a book
Description of picture*
Conversation and reporting
Current work or school*
Social difficulties and annoyance
Emotions
Demonstration task
Cartoons*
Break
Daily living*
Friends, relationships, and marriage
Loneliness
Plans and hopes
Creating a story
Diagnostic accuracy
The social communication difficulties that the ADOS and ADOS-2 seek to measure are not unique to ASD; there is a heightened risk of false positives in individuals with other psychological disorders. In particular, an increased false positive rate has been observed in adults with
psychosis;[9] while case reports indicate that such false positives may also occur in cases of
childhood-onset schizophrenia, which is an exceptionally rare entity with a frequency of 1 in 40000.[10] There is evidence that adults with schizophrenia demonstrate an increased incidence of autistic features compared to the general population, resulting in higher ADOS scores, though schizophrenia patients also experience positive symptoms of psychosis (e.g. hallucinations, delusions, formal thought disorders).[11][12] A 2016 study found that 21% of children with a diagnosis of
ADHD (and without a concurrent diagnosis of ASD) scored in the autism spectrum range on the ADOS total score.[13]
A 2018
Cochranesystematic review included 12 studies of ADOS diagnostic accuracy in pre-school children (Modules 1 and 2). The summary
sensitivity was 0.94 (95%
CI 0.89 to 0.97), with sensitivity in individual studies ranging from 0.76 to 0.98. The summary specificity was 0.80 (95% CI 0.68 to 0.88), with specificity in individual studies ranging from 0.20 to 1.00. The studies were evaluated for bias using the QUADAS-2 framework; of the 12 included studies, 8 were evaluated as having a high risk of bias, while for the remaining four there was insufficient information available for the risk of bias to be properly evaluated. The authors could not identify any studies for the ADOS-2; the scope of the review was limited to preschool age children (mean age under 6 years), which excluded studies of Modules 3 and 4 from the meta-analysis. One included study examined the additive sensitivity and specificity of the ADOS used in combination with the ADI-R; that study found an 11% improvement in specificity (compared to ADOS alone) at the cost of a 14% reduction in sensitivity; however, due to overlapping confidence intervals, that result could not be considered statistically significant.[14]
References
^"Autism Diagnostic Observation Schedule." Western Psychological Services. Western Psychological Services. n.d. Web. 6 March 2010.
^DiLavore, P; Lord, C; Rutter, M (1995). "Pre-Linguistic Autism Diagnostic Observation Schedule (PL-ADOS)". Journal of Autism and Developmental Disorders. 25 (4): 355–379.
^Lord, C; Risi, S; Lambrecht, L; Cook, Jr, E H; Leventhal, B L; DiLavore, P C; Pickles, A; Rutter, M (2000). "The Autism Diagnostic Observation Schedule–Generic: A Standard Measure of Social and Communication Deficits Associated with the Spectrum of Autism". Journal of Autism and Developmental Disorders. 30 (3): 205–223.
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10.1023/A:1005592401947.
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^Barlati S, Deste G, Gregorelli M, Vita A (January 2019). "Autistic traits in a sample of adult patients with schizophrenia: prevalence and correlates". Psychological Medicine. 49 (1): 140–148.
doi:
10.1017/S0033291718000600.
PMID29554995.
S2CID4020382.
Lord C,
Rutter M, Goode S, Heemsbergen J, Jordan H, Mawhood L, Schopler E (June 1989). "Autism diagnostic observation schedule: a standardized observation of communicative and social behavior". Journal of Autism and Developmental Disorders. 19 (2): 185–212.
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10.1007/BF02211841.
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