Autism Diagnostic Observation Schedule

The Autism Diagnostic Observation Schedule (ADOS) is an instrument for diagnosing and assessing autism. It was created by Catherine Lord, Ph.D., Michael Rutter, M.D., FRS, Pamela C. DiLavore, Ph.D., and Susan Risi, Ph.D. in 1989 and became commercially available in 2001 through WPS, or Western Psychological Services. The protocol consists of a series of structured and semi-structured tasks that involve social interaction between the examiner and the subject. The examiner observes and identifies segments of the subject's behavior and assigns these to predetermined observational categories. Categorized observations are subsequently combined to produce quantitative scores for analysis. Research-determined cut-offs identify the potential diagnosis of autism or related autism spectrum disorders, 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 and covers the subject's full developmental history. 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.

Method
The ADOS generally takes from 30 to 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. Each subject is administered activities from just one of the four modules. The selection of an appropriate module is based on the developmental and language level of the referred individual. The only developmental level not served by the ADOS is that for adolescents and adults who are nonverbal. A revision, the ADOS-2, was released in May 2012. It includes improved algorithms for Modules 1 to 3 and a new Toddler Module that facilitates assessment in children ages 12 to 30 months.

Modules
Module 1 is used with children who use little or no phrase speech. Subjects that do use phrase speech but do not speak fluently are administered Module 2. Since these modules both require the subject to move around the room, the ability to walk is generally taken as a minimum developmental requirement to use of the instrument as a whole. Module 3 is for younger subjects who are verbally fluent and Module 4 is used with adolescents and adults who are verbally fluent. Some examples of Modules 1 or 2 include response to name, social smile, and free or bubble play. Modules 3 or 4 can include reciprocal play and communication, exhibition of empathy or comments on others' emotions.

Revision
In 2012, the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) was released by WPS. It includes updated norms and a new Toddler module for assessment of younger children.