An ultrasound investigation of the speech motor skills of stuttering Italian children

Abstract

ABSTRACT This study aims at evaluating speech motor skills in the fluent speech of a cohort of stuttering Italian children. Stuttering is a neurodevelopmental disorder that may arise from an innate limitation of the speech motor control system, which fails to prepare and organize the movements required for fluent speech (Van Lieshout, Hulstijn, & Peters, 2004). Anticipatory coarticulation in CV sequences and stability of speech movements have been used as measures of the maturity of articulatory processes for fluent speech production. This study aims to assess if direct measures of speech dynamics can identify impaired mechanisms in stuttering speech during a phrase-repetition task. The Ultrasound Tongue Imaging data of eight school-aged children, half of whom stutter while the other half don’t, show different articulatory patterns between the two groups, for both motor aspects under investigation. Articulatory data show that the stuttering group presents a higher degree of intra-syllabic coarticulation compared to the control group and decreased stability (i.e. more variability) through multiple repetitions of the same alveolar and velar item. Outcomes of this study suggest that the speech motor control system of children who stutter is less mature in preparing and executing the speech gestures required for fluent speech. This study contributes to shedding light on the impaired articulatory patterns involved in stuttering speech and to identifying the diagnostic markers of the disorder by evaluating the speech of children close to the onset of stuttering.