Abstract
Although “artificial stuttering”, also known as pseudostuttering, represents a well-controlled technique for exploring disfluencies in spontaneous speech, little is known about the exact neural mechanisms involved in pseudostuttering. More specifically, previous research has not considered different types of pseudostuttering symptoms, such as repetitions or prolongations. To address this research gap, we performed functional near-infrared spectroscopy on N = 31 adult participants to measure their brain activity during spontaneous speech under three conditions: habitual (fluent) speech, voluntary produced repetitions, and prolongations. We found greater activation during pseudostuttering than during habitual speech in the left dorsolateral prefrontal cortex, inferior frontal gyrus, middle temporal gyrus, premotor cortex, supplementary motor area, supramarginal gyrus, and superior temporal gyrus, with no significant differences between repetitions and prolongations. These results support previous activation findings obtained during sentence reading and extend them to include activations in the left dorsolateral prefrontal cortex and middle temporal gyrus when producing simulated prolongations and repetitions in naturalistic speech scenarios. Our findings underscore the potential of employing pseudostuttering paradigms in real-world contexts, such as conversational discourse, as a valuable tool to elucidate the neural underpinnings of speech disfluency and its implications for the speaker.