The Autism Diagnostic Interview-Revised (ADI-R) assists with the diagnosis of autism in individuals of all ages. It may also be used as a tool for assessing related disorders known as Autism Spectrum Disorders (ASDs). The ADI-R is an extended interview that produces a range of information.
The interviewer administering the ADI-R must be experienced, and should be accompanied by a caregiver who knows the developmental history and the daily behavior of the patient. The individual being assessed is not present during the interview.
Appropriate Populations for the ADI-R Interview
The assessed individual may be of any age as long as their mental abilities exceed two years and they may be from any setting. It takes between 1 ½ and 2 ½ hours to administer and score the ADI-R. The 85-page ADI-R Interview Protocol booklet includes ninety-three items and is used by the interviewer to record responses.
In clinical situations, any child, adolescent, or adult referred with a diagnostic query regarding ASD qualifies. However, the ADI-R interview can also be used to survey the needs of an entire population for which the clinician has a responsibility, if a high rate of ASD is expected.
This would apply to children with developmental language disorders involving receptive difficulties, individuals with cognitive impairment, individuals with medical conditions commonly associated with ASD, children with congenital blindness, and children with severe institutional deprivation.
The interview can also be used to reach a fuller diagnostic assessment of children with high scores on the Social Communication Questionnaire and research usage provides a means to make these diagnoses using standardized criteria.
Assessing syndrome boundaries and identifying new subgroups is also possible with the ADI-R interview. It is appropriate for individual diagnostic assessment and group trends. It can provide quantification of autistic symptomatology with algorithm scores of separate domains or cumulatively.
Inappropriate Populations for the ADI-R Interview
The validity of the interview is demonstrated in the use of subjects who are of a mental age two and above. It can provide reliable descriptions of behavior for children younger than two as well, but validity is constrained by the fact that autistic features are not usually recognized by caregivers before eighteen months.
Results of screening children below the age of eighteen months produce a high rate of false negatives which suggest that autism is not present when later it was found evident. Subtle abnormalities in autistic children of this age can differentiate them from normally developing children, but they often go unrecognized and do not take the form of autistic behaviors.
Additionally, it is difficult to differentiate a general developmental delay or impairment from autistic behavior at this young age. Pretend play does not develop until after a child is eighteen months, so its absence is not a clear indicator of autistic behavior.
The ADI-R Interview can be used appropriately to obtain a detailed description of behavior in a child or adult with a mental age of two or above, but it does not have the same meaning for individuals with a mental age below two.
Choosing an Informant
The ADI-R Interview focuses on behaviors that are assessed in relation to the ages of four and five years, so the informant must be someone who was familiar with the behavior of the child at that age. This can pose a limitation when care is currently provided in an institutional setting and the informant for current behavior is a staff member.
The interview with a staff member at the institution is a reliable account of current behavior but does not provide the necessary information on early behavior needed for diagnosis. In cases like these, the recommended action is a further interview with a parent or caregiver who knew the child during the preschool years.