Effect of Single and Combined Altered Auditory Feedback on Stuttering Frequency at Two Speech Rates

Abstract

The purpose of the study was to determine if combining delayed auditory feedback (DAF) and frequency altered feedback (FAF) would be more fluency enhancing than either DAF or FAF alone. Ten stutterers read at normal and fast speech rates under nonaltered auditory feedback (NAF), DAF (i.e., a 50 ms delay), FAF (i.e., a one half octave downward shift), and a combination of DAF and FAF [(COMBO), i.e., a 50 ms delay plus a one half octave downward shift]. Results indicated that stuttering frequency was significantly reduced under all altered auditory conditions at both speech rates relative to the NAF condition. There was, however, no significant differences between the altered auditory feedback conditions (i.e., DAF, FAF, and COMBO). It is suggested that further studies be undertaken to explore the combination of altered auditory feedback conditions, as it may be the case that a floor effect was demonstrated with the singular presentations of DAF and FAF and further improvements in fluency enhancement could not be exhibited in the combined condition. Finally, these findings support the notion that a slowed rate of speech is not necessary for fluency enhancement under conditions of altered auditory feedback.