Autism Diagnostic Observation Schedule | |
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Purpose | 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. The ADI-R and ADOS are both considered gold standard diagnostic tests for autism. [1] However, neither of these tests are required by the DSM-5 for an autism diagnosis. [1]
The original ADOS was created by Catherine Lord, Michael Rutter, Pamela C. DiLavore and Susan Risi in 1989. [2] The protocol consisted of 8 tasks meant to assess the individual’s social and communicative behaviors. Behaviors were rated on the following scale:
Some ratings could also be assigned a rating of 7, indicating observed behaviors not otherwise specified. [3]
In response to the need for diagnostic tools for autism in younger children, researchers developed the Pre-Linguistic Autism Diagnostic Observation Schedule (PL-ADOS). [4] The PL-ADOS adapted the content and format of the original ADOS to rely less on verbal communication. It consisted of 12 tasks, retaining only the free/unstructured playtime from the original ADOS and adding new activities designed to be less dependent on speech.
In 2000, Lord and her colleagues introduced the ADOS-Generic (ADOS-G) to assess a broader developmental range of individuals. The ADOS-G introduced a modular format, allowing different protocols to be used depending on developmental and language factors. [5] It became commercially available in 2001 through Western Psychological Services. [6]
The second edition, published in 2012, included updated norms, improved algorithms for Modules 1 to 3, and a new Toddler Module (T) for assessing children aged 12 to 30 months. [7] [8] The scoring algorithm was also revised to align with the recent changes in the DSM-5 diagnostic criteria. While the ADOS-G had separate sections for social and communication behaviors, the ADOS-2 combined these into a single domain to represent social affect, and added a new domain to assess restrictive and repetitive behaviors (RRB).
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. [6] 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. The toddler module algorithm yields a "range of concern" rather than a definite classification. [9]
The toddler module is appropriate for children 12–30 months who use little to no phrase speech and are able to walk independently. [10] This module consists of eleven primary activities: [9]
Module 1 is appropriate for children 31 months and older who use little or no phrase speech. This module consists of ten activities: [7]
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: [7]
Module 3 is appropriate for children or young adolescents who are verbally fluent. This module consists of fourteen activities: [7]
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:
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; [11] 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. [12] 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). [13] [14] 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. [15] False positives have also been found in school-age subjects who have high anxiety or trauma-related disorders; in these cases, the ADOS-2 scores related to repetitive and restrictive behaviors (RRB) are usually lower than typical for ASD. [16]
A 2018 Cochrane systematic 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. [17]
Asperger syndrome (AS), also known as Asperger's syndrome or Asperger's, was a diagnosis used to describe a neurodevelopmental condition characterized by significant difficulties in social interaction and nonverbal communication, along with restricted, repetitive patterns of behavior and interests. Asperger syndrome has been merged with other conditions into autism spectrum disorder (ASD) and is no longer a diagnosis in the WHO's ICD-11 or the APA's DSM-5-TR. It was considered milder than other diagnoses which were merged into ASD due to relatively unimpaired spoken language and intelligence.
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Developmental disorders comprise a group of psychiatric conditions originating in childhood that involve serious impairment in different areas. There are several ways of using this term. The most narrow concept is used in the category "Specific Disorders of Psychological Development" in the ICD-10. These disorders comprise developmental language disorder, learning disorders, developmental coordination disorders, and autism spectrum disorders (ASD). In broader definitions, attention deficit hyperactivity disorder (ADHD) is included, and the term used is neurodevelopmental disorders. Yet others include antisocial behavior and schizophrenia that begins in childhood and continues through life. However, these two latter conditions are not as stable as the other developmental disorders, and there is not the same evidence of a shared genetic liability.
Autism spectrum disorder (ASD) is a neurodevelopmental disorder that begins in early childhood, persists throughout adulthood, and is characterized by difficulties in social communication and restricted, repetitive patterns of behavior. There are many conditions comorbid to autism spectrum disorder, such as attention deficit hyperactivity disorder, anxiety disorders, and epilepsy.
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The Autism Diagnostic Interview-Revised (ADI-R) is a structured interview conducted with the parents of individuals who have been referred for the evaluation of possible autism or autism spectrum disorders. The interview, used by researchers and clinicians for decades, can be used for diagnostic purposes for anyone with a mental age of at least 24 months and measures behavior in the areas of reciprocal social interaction, communication and language, and patterns of behavior.
Classic autism, also known as childhood autism, autistic disorder, (early) infantile autism, infantile psychosis, Kanner's autism, Kanner's syndrome, or (formerly) just autism, is a neurodevelopmental condition first described by Leo Kanner in 1943. It is characterized by atypical and impaired development in social interaction and communication as well as restricted, repetitive behaviors, activities, and interests. These symptoms first appear in early childhood and persist throughout life.
Autism, or autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by repetitive, restricted, and inflexible patterns of behavior, interests, and activities, as well as deficits in social interaction and social communication. Autism generally affects a person's ability to understand and connect with others, as well as their adaptability to everyday situations, with its severity and support needs varying widely across the underlying spectrum. For example, some are nonverbal, while others have proficient spoken language.
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Autism spectrum disorder (ASD) refers to a variety of conditions typically identified by challenges with social skills, communication, speech, and repetitive sensory-motor behaviors. The 11th International Classification of Diseases (ICD-11), released in January 2021, characterizes ASD by the associated deficits in the ability to initiate and sustain two-way social communication and restricted or repetitive behavior unusual for the individual's age or situation. Although linked with early childhood, the symptoms can appear later as well. Symptoms can be detected before the age of two and experienced practitioners can give a reliable diagnosis by that age. However, official diagnosis may not occur until much older, even well into adulthood. There is a large degree of variation in how much support a person with ASD needs in day-to-day life. This can be classified by a further diagnosis of ASD level 1, level 2, or level 3. Of these, ASD level 3 describes people requiring very substantial support and who experience more severe symptoms. ASD-related deficits in nonverbal and verbal social skills can result in impediments in personal, family, social, educational, and occupational situations. This disorder tends to have a strong correlation with genetics along with other factors. More research is identifying ways in which epigenetics is linked to autism. Epigenetics generally refers to the ways in which chromatin structure is altered to affect gene expression. Mechanisms such as cytosine regulation and post-translational modifications of histones. Of the 215 genes contributing, to some extent in ASD, 42 have been found to be involved in epigenetic modification of gene expression. Some examples of ASD signs are specific or repeated behaviors, enhanced sensitivity to materials, being upset by changes in routine, appearing to show reduced interest in others, avoiding eye contact and limitations in social situations, as well as verbal communication. When social interaction becomes more important, some whose condition might have been overlooked suffer social and other exclusion and are more likely to have coexisting mental and physical conditions. Long-term problems include difficulties in daily living such as managing schedules, hypersensitivities, initiating and sustaining relationships, and maintaining jobs.
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Sex and gender differences in autism exist regarding prevalence, presentation, and diagnosis.
Catherine Lord is an American psychologist and researcher. She currently serves as a member of the International Advisory Board for The Lancet Psychiatry, as co-chair of the Scientific Research Council of the Child Mind Institute, and as the George Tarjan Distinguished Professor of Psychiatry and Education at the Semel Institute for Neuroscience and Human Behavior at UCLA.
Daniel S. Messinger is an American interdisciplinary developmental psychologist, and academic. His research works span the field of developmental psychology with a focus on emotional and social development of children and infants, and the interactive behavior of children in preschool inclusive classroom.
The diagnosis of autism is based on a person's reported and directly observed behavior. There are no known biomarkers for autism spectrum conditions that allow for a conclusive diagnosis.