Comparative pitch analysis in young children with and without Autism Spectrum Disorder

Abstract

INTRODUCTION: Children with Autism Spectrum Disorder (ASD) often experience delayed speech development. Current research shows that ASD is associated with atypical vocal quality. Early signs of ASD include difficulties recognizing and using speech prosody, which is how a speaker manipulates changes in pitch, loudness, and duration to emphasize what is important. Pitch is the perceptual representation of fundamental frequency (f0), or the physical speed by which the vocal folds vibrate (cycles per second). Manipulating f0 is a developmental skill that neurotypical children learn in infancy. Children with ASD struggle with this skill. PURPOSE: This study examined differences in pitch among three groups: (1) children diagnosed with ASD, (2) children with developmental delays, and (3) neurotypical children. METHODS: Three children from each group were audio-recorded individually in a naturalistic setting. Acoustic analysis was conducted using PRAAT software. Single syllable utterances were extracted for each child. The f0 of each utterance was analyzed quantitatively and visually (i.e., pitch contour), and compared across the three groups. RESULTS: Children with ASD tended to have higher f0 means and medians than the other groups, but differences were non-significant. CONCLUSION: Fundamental frequency is a critical acoustic vocal parameter and is important in understanding speech development. Future research will include a larger participant pool. Identifying differences in f0 between children with and without ASD can expand the knowledge base of autism diagnostic teams and early interventionists. This knowledge will enable professionals and caregivers to develop more efficient strategies for supporting speech development in children with ASD.