ABSTRACT
This chapter reviews the effects temporal, spectral and intensity perturbations to auditory and vibratory feedback have on fluent speakers and PWS. Early work on Delayed Auditory Feedback (DAF) with fluent speakers, showed that speech errors arise, speakers increase voice level, speech is slowed, medial vowels in syllables are elongated and pitch is monotone. It has been claimed that short-delay DAF produces effects on speech fluency, rate and naturalness that are as good as other forms of altered sensory feedback although this has been contested. Another alternative would be to reduce dosage by ramping intensity of altered auditory feedback down after a dysfluency provided speech is fluent and switch it to its full level when the next episode of stuttering occurs. Overall, temporal delays to speech feedback have a robust effect on fluent speakers and PWS. In fluent speakers, DAF induces a range of disruptions to speech.
