The effects of varying rhythmic stimulus on and off duration on stuttering frequency and speech naturalness

Abstract

This study investigated the effects of varying the duration of a rhythmic stimulus (its “on time”) and the duration of the pauses between stimuli (“off time”) on stuttering frequency and speech naturalness in adults who stutter. Three adult males with developmental stuttering served as participants. Each participant produced monologues while timing his speech to 16 different rhythmic stimulus conditions that varied on time from 0.1 s to 3 s and varied off time from 0.25 s to 1.5 s. Stuttering frequency, listener-rated speech naturalness, and self-rated speech naturalness were measured for each of the conditions. Results showed that stimulus on-time duration was the greatest predictor of both stuttering frequency and speech naturalness. Off-time duration seemed to have little to no effect on stuttering frequency or speech naturalness, for these speakers and these durations. Implications for future research and for clinical applications are discussed.