Speaker
Description
Real-time MRI has transformed the study of speech production by allowing direct visualization of vocal tract movements during running speech. Beyond typical speech, its application to clinical populations has also been increasing. Stuttering offers a tempting test case: stuttering disfluencies have long been identified from auditory-perceptual records, and yet the underlying articulation has rarely been investigated, largely due to challenges in articulatory instrumentation and stuttering elicitation in laboratory settings. We present a real-time MRI approach to studying stuttered speech, combining dynamic vocal tract imaging with a suite of connected speech tasks designed to elicit stuttering during MRI scanning. Seven adults who stutter completed interleaved passage reading, interview, and time-limited picture description tasks. Midsagittal vocal tract movements were imaged using a 0.55T MRI system with high-performance gradients and a custom upper-airway coil. The acquired images have a spatial solution of 2.3 mm and temporal resolution of 10.06 ms. This protocol yielded a rich corpus of stuttered and fluent speech. The resulting data reveal articulatory dynamics that are not recoverable from acoustics alone. Articulation in stuttered speech is largely organized according to the intended linguistic tasks, instead of random, spasmodic movements. Two basic articulatory patterns underpin perceived stuttering: fixation and oscillation of the proximal articulator for the stuttered segment, typically a syllable-onset consonant. Coarticulation between the syllable onset and nucleus appears to be preserved during stuttering, challenging hypotheses that link stuttering occurrences to speech planning disruptions. Together, these findings yield implications for both the phenomenology and theories of stuttering.