A transdiagnostic AI-based measure of interpersonal coordination in autism and other conditions

BACKGROUND: Interpersonal coordination is a fundamental social behavior that has been shown to be reduced in autism, though less is known about other psychiatric conditions. An automated quantitative measure of interpersonal coordination would enhance assessment, diagnosis, and monitoring of treatment-related change in autism and other psychiatric conditions. We introduce and apply a novel AI-based measure ('concurrence') to quantify and compare nonverbal interpersonal coordination during naturalistic conversation in individuals with and without various psychiatric presentations. METHODS: The primary analysis included 380 12-18-year-olds with neurotypical development (NT), autism (AUT), or other psychiatric conditions (PSY), recorded during videoconference get-to-know-you conversations with a research staff member ('partner'). Replication analyses included 72 12-18-year-olds with NT or AUT, recorded during face-to-face conversations. A self-supervised AI method (concurrence) was applied to time series data representing facial expressions and head movements of participants and their conversation partners. This yielded interpersonal coordination scores for all participant-partner dyads, which were then compared transdiagnostically. Convergent and discriminant validity were assessed using annotated subsamples from a combined sample of 609 5-52-year-olds. Convergent validity was assessed with measures of social gaze, motor imitation ability, and conversation quality; discriminant validity was assessed with IQ scores. RESULTS: In the videoconference sample, AUT demonstrated significantly lower interpersonal coordination than PSY (unadjusted Cohen's d = 0.46, p < 0.001) and NT (d = 1.03, p < 0.001), with PSY also lower than NT (d = 0.50, p < 0.001). The AUT < NT effect was replicated in the face-to-face sample (d = 0.73, p < 0.05). The group-by-context interaction was nonsignificant (p = 0.33), suggesting group differences are robust to recording context. Convergent and discriminant validity was demonstrated through positive associations between interpersonal coordination and mutual social gaze (r(108) = 0.46, p < 0.0001), gross motor imitation ability (r(35) = 0.41, p < 0.05), and conversation quality ratings (r(364) = 0.34, p < 0.0001), but not IQ (r(367) = 0.03, p = 0.55). LIMITATIONS: Generalizability is limited by sample characteristics including cognitive and verbal ability, age, and sex. CONCLUSIONS: The study demonstrates reduced interpersonal coordination in adolescents with autism and other psychiatric conditions (AUT<PSY<NT) using a novel, transdiagnostic computational measure. This finding replicated across different conversational contexts and the concurrence measure demonstrated convergent and discriminant validity, highlighting its potential as an automated and scalable individual-level measure of social skills.