The Adapted ADOS - Preliminary Findings Using a Modified Version of the ADOS for Adults Who Are Nonverbal or Have Limited Language

Background: The Autism Diagnostic Observation Schedule (ADOS; Lord et al., 2000) is widely used in both research and clinical diagnostic evaluations. However, Module 4, the only module intended for adults, is limited to use with individuals who are verbally fluent. Modules 1 and 2, appropriate for individuals who are nonverbal or have limited language, have not been validated in adult samples. Because these instruments were intended for use with young children, many of the materials and activities were chosen to maximize opportunities for social interaction, such as requests and shared enjoyment, between the child and examiner. These activities and materials may not be interesting to and/or appropriate for use with adults. In addition, items used to score behavior in young children may not be of the same diagnostic utility in older individuals. 

Objectives: To adapt ADOS Modules 1 & 2 to be appropriate for use with adults who are nonverbal or have limited language. 

Methods: To create the Adapted ADOS, Module 1 and 2 activities and materials were modified to be more interesting and appropriate for adults. A pilot version of the Adapted ADOS was administered to 61 adults with ASD or non-spectrum diagnoses. Participants ranged from 18-25 years of age. Protocol and algorithm items were chosen based on their ability to successfully discriminate ASD and non-ASD groups.  Total scores were generated from the algorithm items and Receiver Operating Curves (ROC; Siegel et al., 1989) were calculated to determine appropriate diagnostic cut-offs.

Results: Modifications included changes to materials and activities. For example, Free Play toys were substituted with new, more adult-oriented materials (e.g., a real cell phone, a CD player) and some objects from the Module 3/4 Break. A new Conversation activity was added to Module 2 to provide an additional opportunity to observe whether the presence of supporting materials facilitates the participant’s ability to carry on a conversation with the examiner.  Ninety-seven percent of adults with ASD and 100% of adults with non-spectrum diagnoses shifted attention to a target across the room in response to the examiner’s shift in eye gaze or point. Given the high rate of response, the Response to Joint Attention activity was removed from the protocol. For adults receiving a Module 1, sensitivity of 83% and specificity of 75% was achieved. For adults receiving Module 2, sensitivity was 93% and specificity was 71%. 

Conclusions: The Adapted ADOS Modules 1 and 2 appear to be useful for the assessment of adults who are nonverbal or have limited language. Some behaviors that are diagnostically significant in young children (e.g., Response to Joint Attention) did not differentiate adults with and without ASD. These results are preliminary and the utility of the Adapted ADOS must be explored in larger samples. However, it is anticipated that these measures will facilitate future efforts to understand how ASD-related symptoms manifest across the lifespan.