Speech intonation in children with autism spectrum disorder

Objective: The prosody of children with autism spectrum disorder (ASD) has several abnormal features. We assessed the speech tone of children with ASD and of children with typical development (TD) by using a new quantitative acoustic analysis. Methods: Our study participants consisted of 63 children (26 with ASD and 37 with TD). The participants were divided into 4 groups based on their developmental features and age. We assessed the variety of the fundamental frequency (F0) pattern quantitatively, using pitch coefficient of variation (CV), considering the different F0 mean for each word. Results: (1) No significant difference was observed between the ASD and TD group at pre-school age. However, the TD group exhibited significantly greater pitch CV than the ASD group at school age. (2) In pitch CV, range and standard deviation of the whole speech of each participant, no significant differences were observed between the type of participants and age. (3) No significant correlation was found between the pitch CV of each word and the Japanese Autism Screening Questionnaire total score, or between the pitch CV of each word and the intelligence quotient levels in the ASD group. A significant correlation was observed between the pitch CV of each word and social reciprocal interaction score. Conclusions: We assessed the speech tone of children with ASD by using a new quantitative method. Monotonous speech in school-aged children with ASD was detected. The extent of monotonous speech was related to the extent of social reciprocal interaction in children with ASD.