The Development of a Coding System for Social-Communication Behaviors for the ADOS

Background: Social-communication behaviors are viewed as pivotal skills and are common targets for intervention in young children with an autism spectrum disorder (ASD). In order to examine the impact of these interventions, it is essential to have measurement tools to assess change in social-communication skills. Indeed, researchers have highlighted the importance of using measurement tools that correspond to the targets of a given intervention (Kasari, 2002). The Autism Diagnostic Observation Schedule (ADOS) is a tool that is used for diagnostic purposes, but has also been utilized to measure change for descriptive and intervention studies. Modules 1 and 2 of the ADOS offer opportunities for elicited and spontaneous social-communication through a variety of semi-structured tasks in naturalistic and play-based settings.

Objectives: The goal of this research was to develop a reliable and valid coding system to utilize with repeated administrations of the ADOS to assess social-communication behaviors in preschool children with ASD. The coding scheme focused on three broad categories of social communication: social interaction (SI), requests (RQ), and joint attention (JA).

Methods: The development team used the social-communication hierarchy from the Advancing Social-Communication and Play intervention (ASAP; Watson, Boyd, et al., 2009) as a starting point for selecting target behaviors. Using previous literature, existing social-communication measures, and research and clinical experience, initial coding definitions were created. The team viewed ADOS videos from previous phases of the intervention. Following these reviews and team discussions, examples, non-examples, and decision rules were added to the coding manual. Next, the team individually viewed additional ADOS videos and coded social-communication behaviors. The coding manual was revised to maximize reliability. Finally, a weighting system was devised using literature on the development of social-communication behaviors. Thus far, ADOS videos from twenty-eight of thirty-two subjects have been coded at pre- and post-test. The following data are based on the ADOS videos

Results: The final coding system includes three sub-scales of social-communication categories (SI, RQ, and JA), with four to six behaviors within each category, for a total of 15 targeted social-communication behaviors. Inter-rater reliability was examined on 20% of the videos using intra-class correlations (ICCs) for the total and sub-scale scores. The ICC was .946 for overall score, and ranged from .765 to .938 on the sub-scales. Pre- and post-test total scores were significantly correlated (r=.77) and the scores also showed consistent positive change from pre- to post-test across participants, suggesting the coding system is capturing a stable construct yet is sensitive to change. Additionally, the researchers explored concurrent validity of the coding system. The total scores for the ADOS social-communication coding system were significantly correlated with the age equivalents from the Mullen Expressive Language subscale (r=.557).

Conclusions: The coding system developed for use with Module 1 and 2 ADOS assessments is a reliable method for measuring social-communication behaviors of preschool children with ASD. Advantages and challenges of the specific coding system and use of video-taped ADOS assessments will be discussed. Also, the researchers will share practical tips for application in an intervention study.