Abstract
Atypical vocalizations are commonly observed in infants who go on to be diagnosed with autism spectrum disorder (ASD), and atypical vocalization qualities are found across the lifespan for individuals with ASD. The current study examined the quality of automatically-identified toddler vocalizations (15 months) and cries and toddler directed adult vocalizations during both low and high stress interactions as a potential predictor of later ASD diagnosis and symptom levels. Vocalizations of 15-month-old children with later (36 months) ASD diagnoses (EL/ASD, N=15), and at elevated familial likelihood for ASD without an ASD outcome (EL/No-ASD, N=37) and low likelihood without later ASD (LL/No-ASD, N=40) were identified during the Strange Situation Procedure (SSP). The pitch of child and adult vocalizations (mean F0) and child cry duration differed between Low Stress and High Stress (Stranger Introduction, Separation with Stranger, Child Alone, Reunion with Parent) SSP episodes for the sample overall. Adult vocalizations toward toddlers at elevated likelihood without later ASD had higher mean F0 than adult vocalizations toward toddlers at low likelihood for ASD. For children who cried during the low stress interaction, cry mean F0 was higher for children with ASD than those with elevated likelihood but no diagnosis. Higher mean F0 of child non-cry vocalizations during the Child Alone episode was associated with lower later Restricted and Repetitive Behavior (RRB) symptoms. A greater number of cry instances while the child was left alone was associated with lower later Social Affect (SA) symptoms. Early vocalization quality may contribute to earlier predictions of later ASD diagnoses and symptoms when considered in a corpus of early markers.