A Comprehensive Analysis of Speech Disfluencies in Autistic Young Adults and Control Young Adults: Group Differences in Typical, Stuttering-Like, and Atypical Disfluencies

Abstract

Purpose: The purpose of this study was to examine the nature of speech disfluencies in autistic young adults and controls by using a wide-range disfluency classification of typical disfluencies (TD; i.e., filled pauses, revisions, abandoned utterances, and multisyllable word and phrase repetitions), stuttering-like disfluencies (SLD; i.e., sound and syllable repetitions, monosyllable word repetitions, prolongations, blocks, and broken words), and atypical disfluencies (AD; i.e., word-final prolongations and repetitions and atypical insertions). Method: Thirty-two autistic young adults and 35 controls completed a narrative telling task based on socially complex events. Frequencies of total disfluencies, TD, SLD, AD and stuttering severity were compared between groups. Results: The overall frequency of disfluencies was significantly higher in the autistic group and significant between-group differences were found for all disfluency categories. The autistic group produced significantly more revisions, filled pauses, and abandoned utterances, and each subtype of SLD and AD than the control group. In total, approximately every fourth autistic participants scored at least a very mild severity of stuttering, and every fifth produced more than three SLD per 100 syllables. Conclusions: Disfluent speech can be challenging for effective communication. This study revealed that the speech of autistic young adults was highly more disfluent than that of the controls. The findings provide information on speech disfluency characteristics in autistic young adults and highlight the importance of evaluating speech disfluency with a wide-range disfluency classification in autistic persons in order to understand their role in overall communication. The results of this study offer tools for SLPs to evaluate and understand the nature of disfluencies in autistic persons.