This study aimed to increase our understanding of the underlying mechanisms of vocal control in frequency-altered conditions of auditory feedback for people who do and who do not stutter by assessing the vocal responses to perturbations in pitch of auditory feedback. Past research has shown that the speech of people who stutter improves during frequency-altered feedback, but the mechanisms responsible for this fluency remain unclear. Typically, brief modulations in pitch of voice auditory feedback lead to short-latency corrective voice F0 responses during sustained phonations in non-stuttering individuals. However, data are lacking regarding audio-vocal control mechanisms in individuals that stutter. Brief upward (+) and downward (-) perturbations in pitch (50 or 600 cents in magnitude) lasting 200 ms in duration were introduced intermittently into vocalizing subject's auditory feedback. Four mild to moderate developmental stutterers and four gender-matched non-stutterers were tested using the "pitch-shift paradigm." Analysis of vocal reflex parameters elicited by 50 cent perturbations in pitch indicated that voice F0 responses during sustained vowels were more variable, slower in latency, and more likely to decrease in F0 in individuals that stutter compared to gender-matched controls. However, responses were more similar for 600 cent stimuli.

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