An Examination of Articulatory Precision in Autistic Children and Adults.

Abstract

According to the speech attunement framework, autistic individuals lack the ability and/or motivation to "tune up" their speech to the same level of precision as their neurotypical peers. However, previous studies exploring the articulatory patterns of autistic individuals have yielded disparate findings. One reason contrasting conclusions exist may be because studies have relied on perceptual measures of articulation. Here, we use an objective acoustic measure of articulatory precision to explore the articulatory patterns of autistic children and adults. This was a retrospective analysis of an existing corpus of 900 recorded speech samples taken from 30 adult and 30 child participants across two different population groups: autistic individuals (autism spectrum disorder [ASD] group) and neurotypical individuals (neurotypical [NT] group). Articulatory precision scores were calculated using an automated metric that compares observed acoustics to the expected acoustics for each phoneme production. Linear mixed-effects models were used to compare the articulatory precision scores across population group (i.e., ASD group vs. NT group) and to see if these differences were moderated by age group (i.e., children vs. adult). The speech of autistic individuals was characterized by reduced articulatory precision relative to their neurotypical peers. This pattern was not significantly moderated by age, indicating it occurred in both the children and adult groups. Our preliminary findings indicate that imprecise articulation may be a characteristic of the speech of autistic individuals in both childhood and adulthood. These findings are in line with predictions posited by the speech attunement framework. Given the current lack of speech markers for this clinical population and the importance of speech quality in the social integration of autistic individuals, our results advance articulatory precision as a viable and important target for future research.