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 original ADOS was created by Catherine Lord, Michael Rutter, Pamela C. DiLavore and Susan Risi in 1989. [1]
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.
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]
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).
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]
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]
Module 1 is appropriate for children 31 months and older who use little or no phrase speech. This module consists of ten activities: [5]
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]
Module 3 is appropriate for children or young adolescents who are verbally fluent. This module consists of fourteen activities: [5]
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; [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 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. [14]
Asperger syndrome (AS), also known as Asperger's syndrome, formerly described a neurodevelopmental disorder characterized by significant difficulties in social interaction and nonverbal communication, along with restricted and repetitive patterns of behavior, interests, and activities. The syndrome has been merged with other disorders into autism spectrum disorder (ASD) and is no longer considered a stand-alone diagnosis. It was considered milder than other diagnoses that were merged into ASD by relatively unimpaired spoken language and intelligence.
The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), was a group of disorders characterized by delays in the development of multiple basic functions including socialization and communication. It was defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM), and the International Classification of Diseases (ICD).
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, motor disorders, and autism spectrum disorders. In broader definitions 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.
Pervasive developmental disorder not otherwise specified (PDD-NOS) is a historic psychiatric diagnosis first defined in 1980 that has since been incorporated into autism spectrum disorder in the DSM-5 (2013).
Autism spectrum disorders (ASD) are neurodevelopmental disorders that begin in early childhood, persist throughout adulthood, and affect three crucial areas of development: communication, social interaction and restricted patterns of behavior. There are many conditions comorbid to autism spectrum disorders such as attention-deficit hyperactivity disorder and epilepsy.
The epidemiology of autism is the study of the incidence and distribution of autism spectrum disorders (ASD). A 2022 systematic review of global prevalence of autism spectrum disorders found a median prevalence of 1% in children in studies published from 2012 to 2021, with a trend of increasing prevalence over time. However, the study's 1% figure may reflect an underestimate of prevalence in low- and middle-income countries.
A spectrum disorder is a disorder that includes a range of linked conditions, sometimes also extending to include singular symptoms and traits. The different elements of a spectrum either have a similar appearance or are thought to be caused by the same underlying mechanism. In either case, a spectrum approach is taken because there appears to be "not a unitary disorder but rather a syndrome composed of subgroups". The spectrum may represent a range of severity, comprising relatively "severe" mental disorders through to relatively "mild and nonclinical deficits".
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.
Several factors complicate the diagnosis of Asperger syndrome (AS), an autism spectrum disorder (ASD). Like other ASD forms, Asperger syndrome is characterized by impairment in social interaction accompanied by restricted and repetitive interests and behavior; it differs from the other ASDs by having no general delay in language or cognitive development. Problems in diagnosis include disagreement among diagnostic criteria, the controversy over the distinction between AS and other ASD forms or even whether AS exists as a separate syndrome, and over- and under-diagnosis for non-technical reasons. As with other ASD forms, early diagnosis is important, and differential diagnosis must consider several other conditions.
Autism, formally called autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental disorder marked by deficits in reciprocal social communication and the presence of restricted and repetitive patterns of behavior. Other common signs include difficulty with social interaction, verbal and nonverbal communication, along with perseverative interests, stereotypic body movements, rigid routines, and hyper- or hyporeactivity to sensory input. Autism is clinically regarded as a spectrum disorder, meaning that it can manifest very differently in each person. For example, some are nonspeaking, while others have proficient spoken language. Because of this, there is wide variation in the support needs of people across the autism spectrum.
Childhood schizophrenia is similar in characteristics of schizophrenia that develops at a later age, but has an onset before the age of 13 years, and is more difficult to diagnose. Schizophrenia is characterized by positive symptoms that can include hallucinations, delusions, and disorganized speech; negative symptoms, such as blunted affect and avolition and apathy, and a number of cognitive impairments. Differential diagnosis is problematic since several other neurodevelopmental disorders, including autism spectrum disorder, language disorder, and attention deficit hyperactivity disorder, also have signs and symptoms similar to childhood-onset schizophrenia.
The imprinted brain hypothesis is an unsubstantiated hypothesis in evolutionary psychology regarding the causes of autism spectrum and schizophrenia spectrum disorders, first presented by Bernard Crespi and Christopher Badcock in 2008. It claims that certain autistic and schizotypal traits are opposites, and that this implies the etiology of the two conditions must be at odds.
Diagnosis, treatment, and experiences of autism varies globally. Although the diagnosis of autism is rising in post-industrial nations, diagnosis rates are much lower in developing nations.
The history of autism spans over a century; autism has been subject to varying treatments, being pathologized or being viewed as a beneficial part of human neurodiversity. The understanding of autism has been shaped by cultural, scientific, and societal factors, and its perception and treatment change over time as scientific understanding of autism develops.
The Modified Checklist for Autism in Toddlers (M-CHAT) is a psychological questionnaire that evaluates risk for autism spectrum disorder in children ages 16–30 months. The 20-question test is filled out by the parent, and a follow-up portion is available for children who are classified as medium- to high-risk for autism spectrum disorder. Children who score in the medium to high-risk zone may not necessarily meet criteria for a diagnosis. The checklist is designed so that primary care physicians can interpret it immediately and easily. The M-CHAT has shown fairly good reliability and validity in assessing child autism symptoms in recent studies.
Sex and gender differences in autism exist regarding prevalence, presentation, and diagnosis.
Daniel 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.