Mechanisms of voice control related to prosody in autism spectrum disorder and first-degree relatives

Differences in prosody (e.g., intonation, rhythm) are among the most obvious language-related impairments in autism spectrum disorder (ASD), and significantly impact communication. Subtle prosodic differences have also been identified in a subset of clinically unaffected first-degree relatives of individuals with ASD, and may reflect genetic liability to ASD. This study investigated the neural basis of prosodic differences in ASD and first-degree relatives through analysis of feedforward and feedback control involved in the planning, production, self-monitoring, and self-correction of speech by using a pitch-perturbed auditory feedback paradigm during sustained vowel and speech production. Results revealed larger vocal response magnitudes to pitch-perturbed auditory feedback across tasks in ASD and ASD parent groups, with differences in sustained vowel production driven by parents who displayed subclinical personality and language features associated with ASD (i.e., broad autism phenotype). Both ASD and ASD parent groups exhibited increased response onset latencies during sustained vowel production, while the ASD parent group exhibited decreased response onset latencies during speech production. Vocal response magnitudes across tasks were associated with prosodic atypicalities in both individuals with ASD and their parents. Exploratory event-related potential (ERP) analyses in a subgroup of participants during the sustained vowel task revealed reduced P1 ERP amplitudes in the ASD group, with similar trends observed in parents. Overall, results suggest underdeveloped feedforward systems and neural attenuation in detecting audio-vocal feedback may contribute to ASD-related prosodic atypicalities. Importantly, results implicate atypical audio-vocal integration as a marker of genetic risk to ASD, evident in ASD and among clinically unaffected relatives. Autism Res 2019, 12: 1192–1210.