LAUSR

The Autism Diagnostic Observation Schedule, Second Edition (ADOS‐2) constitutes one of the most widely used diagnostic instruments for autism and involves a direct face‐to‐face interaction between clinician and child. During the COVID‐19 pandemic, administration of the ADOS‐2 continued in several countries, with the requirement of face mask protection. It has been hypothesized that mask wearing may have disrupted the dynamic of child‐clinician interaction and differentially affected toddlers with autism. We compared ADOS‐2 algorithm scores between cohorts of toddlers evaluated before (pre‐COVID‐19, n = 232) and during the pandemic (COVID‐19, n = 116). The COVID‐19 cohort included 41 toddlers with autism spectrum disorders (AUT, Mage = 25.4, SD = 3.8), 34 toddlers with other neurodevelopmental conditions (NDC, Mage = 22.3, SD = 5.0), and 41 typically developing toddlers (TD, Mage = 20.4, SD = 3.6) recruited between September 2020 and April 2023. The pre‐COVID‐19 cohort was selected from 409 assessments conducted from January 2013 to March 2020. Propensity matching was used to match the pre‐ and COVID‐19 cohorts on sex, chronological age, and verbal and nonverbal developmental quotient (DQ) scores. Ordered logistic regression analyses were computed for social affect (SA) and restricted and repetitive behaviors (RRB) algorithm total and item scores, with cohort (pre‐COVID‐19/COVID‐19) as a fixed factor for each diagnostic group. The analyses revealed a limited impact of cohort on the algorithm scores in all three diagnostic groups. Item‐level analysis revealed a significant cohort effect only on two out of 20 items: shared enjoyment and joint attention, with higher (more atypical) scores found in the COVID‐19 than in the pre‐COVID‐19 cohorts. The resiliency of the algorithm and item‐level scores to the effect of masking speaks to the strength of the diagnostic tool and its ability to capture a range of social, communication, and repetitive behaviors under both standard and nonstandard conditions.