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

The Autism Diagnostic Interview-Revised, better known as the ADI-R, is one of a battery of tests used to screen for and diagnose children with autism. Because there is no medical test for autism, evaluators rely on a variety of tools including checklists, observations, interactive tests, and interview questions that are administered to the parents of young children with possible symptoms of autism or an autism spectrum disorder. 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).

Screening Tests for Autism

Autism has become an increasingly common diagnosis, with one in 59 children now diagnosed with autism. At the same time, symptoms of autism overlap with symptoms of many other developmental and physical disorders. For example:

• A toddler who doesn't respond to his own name may be hard of hearing.
• 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 disorder 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." These are relatively quick, simple evaluations that provide enough information to determine whether there is a need for further assessments.

In the past, screenings for developmental delays were more likely to focus on "gross" 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.

In recent years, however, pediatricians have also begun screening for "high level" forms of autism and related disorders which include no obvious speech delay. Two of the more popular screening tools for high-functioning autism include the Autism Spectrum Screening Questionnaire (ASSQ), the Australian Scale for Asperger’s Syndrome, and the most recent, the Childhood Asperger Syndrome Test (CAST). All of 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 symptoms of autism, he or she may recommend more extensive evaluations. If your pediatrician does not perform autism screenings and you have concerns, ask for the screenings. If your healthcare provider is not familiar with autism screening tools you may choose to go to a developmental pediatrician or another specialist.

Diagnostic Tests for Autism

Screening tests don't necessarily indicate that a child is autistic, though they can provide clues as to whether a child has delays or differences that warrant further investigation. A full evaluation involves tests which 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 which 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
• "Autistic" 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
• 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. For very young children two other tests, The Screening Tool for Autism in Toddlers and Young Children (STAT) and the Communication and Symbolic Behavior Scales (CSBS) are often implemented. The Autism Diagnosis Interview-Revised (ADI-R), a parent interview tool, is almost always included in the diagnostic process.

About the ADI-R

The ADI-R is a parent interview which, according to the Autism Genetic Research Exchange website (AGRE), "contains 93 items and focuses on behaviors in three content areas or domains: 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); and repetitive, restricted and stereotyped interests and behavior (e.g., unusual preoccupations, hand and finger mannerisms, unusual sensory interests). The measure also includes other items relevant for treatment planning, such as self-injury and over-activity."

The 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, and so forth. Both verbal and non-verbal communication and social skills are scored, with reference to the child's chronological age. Scores are generated in the areas of communication and language, social interaction, and restricted 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 onset of the disorder is evident by 36 months of age."

About the Diagnostic Process

Of course, the ADI-R should not be the only evaluation tool used to diagnose an autism spectrum diagnosis. Ideally, in fact, an autism diagnosis should involve not a single individual but a team. Members of the team should include a pediatrician (ideally 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, or social communication disorder).

How to Set Up an Evaluation for Your Child

In most cases, you have 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 is required to pay for certain evaluations and can provide non-medical experts such as a speech-language pathologist and occupational therapist to assess your child. It's important to bear in mind, however, that independent assessments may be useful as you begin to work with the school to develop an educational and therapeutic plan.