The ADI-R and Other Tests Used to Make an Autism Diagnosis

Updated on 2024-02-19 15:23:51 0 0

ADI-R is one of several tests used to screen for and diagnose autism

By Lisa Jo Rudy

Medically reviewed by Nicholas R. Metrus, MD

The Autism Diagnostic Interview-Revised, better known as the ADI-R, is among the tests used to screen for and diagnose children with autism. Because there is no medical test for autism, evaluators rely on checklists, interactive tests, observations, and interviews of parents of young children with suspected traits of autism spectrum disorder (ASD).1

Some of the most commonly used tests include the Checklist of Autism in Toddlers (CHAT), the modified Checklist for Autism in Toddlers (M-CHAT), the Screening Tool for Autism in Two-Year-Olds (STAT), and the Social Communication Questionnaire (SCQ).

This article will discuss the ADI-R for autism, other screening or diagnostic tests, and how to set up an evaluation for a child in your care.

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About the ADI-R

The ADI-R is a parent interview, which contains 93 items and focuses on behaviors in three content areas or domains:2

Quality of social interaction (e.g., emotional sharing, offering and seeking comfort, social smiling, and responding to other children)
Communication and language (e.g., stereotyped utterances, pronoun reversal, social usage of language)
Repetitive, intensely focused, and stereotyped interests and behavior (e.g., unusual preoccupations, hand and finger mannerisms, unusual sensory interests).

The measure includes other items relevant to treatment planning, such as self-injury and over-activity.2

The ADI-R test asks both general and specific questions. For example, parents are asked about their child's communication abilities with special reference to topics such as pointing, head nodding, etc.

Both verbal and nonverbal communication and social skills are scored concerning the child's chronological age. Scores are generated in the areas of communication and language, social interaction, and intensely focused or repetitive behaviors.

A higher score indicates a potential developmental delay. According to AGRE, "A classification of autism is given when scores in all three content areas of communication, social interaction, and patterns of behavior meet or exceed the specified cutoffs, and the onset of the disorder is evident by 36 months of age."2

While the ADR-I is an evidence-based approach to identifying kids with autistic traits, it does have limitations. It must be interpreted appropriately by the clinician and relies on subjective observations by caregivers. It does not include an assessment of the child firsthand. Still, a study on its reliability in clinical settings (not just research settings) reinforced that it is often a reliable test.3

Screening Tests for Autism

Autism has become an increasingly common diagnosis, with one in 36 children now diagnosed with it.4 At the same time, traits of autism overlap with the symptoms of many developmental and physical disorders. For example:

A toddler who doesn't respond to their own name may be hard of hearing, not autistic.
A youngster who has difficulty relating to others may have a social phobia or anxiety.
A preschooler who is slow to develop spoken language may have any of several speech-related disorders, including apraxia of speech.

To determine whether an infant, toddler, or young child has a developmental delay—and the extent and quality of any delay—pediatricians conduct "well-child screenings."1 These are relatively quick, simple evaluations that provide enough information to determine whether there is a need for further assessments.

Previously, screenings for developmental delays were more likely to focus on "gross" or broad issues such as lack of spoken language, delays in reaching major developmental milestones, or significant behavioral differences. For example, a baby or toddler who was not babbling or pointing by a particular age would be identified as being at risk for autism.

But pediatricians also began screening for "high level" forms of autism, now described as autism with low support needs, and related disorders which include no apparent speech delay. These tests screen for social and behavioral impairments, delays, and differences rather than for speech or motor delays.

If your pediatrician performs one or more of these screening tests and is concerned about possible autism traits, they may recommend more extensive evaluations.

If the pediatrician does not perform routine autism screenings and you have concerns, request the screenings. If your healthcare provider is not familiar with autism screening tools, consider going to a developmental pediatrician or another specialist.

Diagnostic Tests for Autism

Screening tests don't necessarily identify an autistic child, though they can provide clues as to whether a child has delays or differences that warrant further investigation. A complete evaluation involves tests that can actually lead to a formal diagnosis of autism spectrum disorder.

Because there is no medical test for autism, evaluators are reliant—even for a formal diagnosis—on observations, parent responses to questions, and tests that assess a child's skills and behaviors in several areas of development. Implemented by a team of evaluators, these tests may assess:

Speech and language
Non-verbal social communication
Joint attention
Sensory sensitivities
Focused or repetitive behaviors such as lining up toys, specific types of "stimming," etc.
Interest in and ability to engage in social activity with peers
Play interests and style
Physical development from infancy
IQ test results
Ability to copy or repeat words or actions

Some of the most commonly used tests include the Autism Diagnostic Observation Schedule (ADOS-G) and the Childhood Autism Rating Scale (CARS). ADOS-G tests for social communication skills and behaviors.

Two other tests are often implemented for very young children: The Screening Tool for Autism in Toddlers and Young Children (STAT) and the Communication and Symbolic Behavior Scales (CSBS). The Autism Diagnosis Interview-Revised (ADI-R), a parent interview tool, is almost always included in the diagnostic process.1

About the Diagnostic Process

Of course, the ADI-R should not be the only evaluation tool used for an ASD diagnosis.5 Ideally, an autism diagnosis should involve not a single individual but a team.

Members of the team should include a pediatrician (preferably an individual with a specialty in developmental disorders), a psychologist, a speech and language pathologist, and an occupational therapist.

These specialists can conduct a range of assessments that look for specific types of challenges and behaviors that would indicate autism (as opposed to or in addition to other, related disorders such as:

ADHD
Obsessive-compulsive disorder
Social anxiety
Hearing loss
Social communication disorder

What's the Difference Between the ADOS and the ADR-I?

The Autism Diagnostic Observation Schedule (ADOS) is another assessment used to identify autism. It is different from the ADI-R because it involves a clinician's direct observation of the child. The ADI-R is based solely on observations by the child's caregivers.6

How to Set Up an Evaluation for Your Child

In most cases, there are a few options for evaluation. You may choose to start with your pediatrician, who may be able to recommend an autism clinic or center where your child can be evaluated. You may also choose to work through your school district.

The district must pay for certain evaluations and can provide non-medical experts, such as a speech-language pathologist and occupational therapist, to assess your child. Bear in mind, however, that independent assessments may be helpful as you begin to work with the school to develop an educational and therapeutic plan.

How to Prepare for the ADI-R

As you prepare for your ADI-R appointment, take some time to think back over your child's life and remember when developmental milestones occurred. When did your child begin to roll over, sit unassisted, stand, crawl, "cruise" (walking while supported by furniture), walk, etc.? Make some notes about your child's strengths and weaknesses. Review medical records to see observations your child's pediatrician made. And consider asking other people in your child's life for their impressions.

Summary

The ADI-R is a test where caregivers of the child are asked an array of questions about the child to screen for and diagnose autism. It focuses on social interaction, communication and language skills, and any hyperfixation of specific interests or sensory input. Higher scores are more indicative of an autism diagnosis. Healthcare providers such as psychologists, neuropsychiatrists, and occupational or speech therapists may be part of the diagnostic team.

6 Sources

National Institute of Mental Health. Autism Spectrum Disorder.

Sophy Kim SH, Bal VH, Lord C. Autism diagnostic interview-revised. In: Volkmar FR, ed. Encyclopedia of Autism Spectrum Disorders. Springer International Publishing. 2021:470-475.

Zander E, Willfors C, Berggren S, et al. The interrater reliability of the autism diagnostic interview-revised (ADI-R) in clinical settings. Psychopathology. 2017;50(3):219-227. doi:10.1159/000474949

Centers for Disease Control and Prevention. Prevalence and Characteristics of Autism Spectrum Disorder Among Children Aged 8 Years — Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2020.

Randall M, Egberts KJ, Samtani A, et al. Diagnostic tests for autism spectrum disorder (ASD) in preschool children. Cochrane Database Syst Rev. 2018;7(7):CD009044. doi:10.1002/14651858.CD009044.pub2

Frigaux A, Evrard R, Lighezzolo-Alnot J. ADI-R and ADOS and the differential diagnosis of autism spectrum disorders: Interests, limits and openings. Encephale. 2019;45(5):441-448. doi:10.1016/j.encep.2019.07.002