A sensorimotor approach to disfluency adaptation in typically fluent adults

Delaying auditory feedback (DAF) during speech is a potent auditory perturbation that can interrupt and prolong syllables and words, even though these disfluencies rarely affect typical speakers under non-altered feedback (NAF). Adaptation or compensation to auditory perturbations has been shown in typical speakers through a gradual reduction in the amplitude of formant shift responses. However, despite considerable research on DAF, it is still not known whether typical speakers adapt to DAF. In this study, we tested whether a comparable form of adaptation occurs with DAF in typical speakers as shown by a reduction in altered feedback disfluencies (AFD) during repeated consecutive readings, after a pause between readings and to a novel reading. We then tested for carryover effects after a single DAF exposure. A significant decrease in AFD rate was observed in 38 speakers that was sustained after a pause and for a novel reading. The adaptation effect extended to articulation rate (syllables/sec) in that rate increased for all speakers across readings. Evidence for carryover effects was inconclusive. By showing that typical speakers can adapt to DAF, the findings support a sensorimotor approach to auditory perturbation adaptation achieved through motor practice.