Abstract
Few measures are appropriate to assess autism symptoms in minimally verbal adolescents and adults. The Autism Diagnostic Observation Schedule, 2nd Edition (ADOS-2, Lord et al., in Autism diagnostic observation schedule-2nd edition (ADOS-2). Western Psychological Services, Los Angeles, 2012) Modules 1 and 2 were designed and validated with children whose spoken language ranges from few- to- no words to phrase speech. This study describes the development and initial validation of the Adapted-ADOS (A-ADOS), which includes tasks, materials and behavioral codes modified to be suitable for assessing older minimally verbal individuals. A-ADOS algorithms exhibit comparable sensitivity and improved specificity relative to ADOS-2 Modules 1 and 2. Although further validation is needed, the A-ADOS will facilitate research to further understanding of minimally verbal adults and symptom trajectories across the lifespan.