title: An experimental investigation of the effect of altered auditory feedback on the conversational speech of adults who stutter.
abstract: OBJECTIVE
  To investigate the impact on percentage of syllables stuttered of various durations of delayed auditory feedback (DAF), levels of frequency-altered feedback (FAF), and masking auditory feedback (MAF) during conversational speech.
  
  
  METHODS
  Eleven adults who stuttered produced 10-min conversational speech samples during a control condition and under 4 different combinations of DAF, FAF, and MAF. Participants also read aloud in a control condition with DAF and FAF.
  
  
  RESULTS
  A statistically significant difference was found between the NAF conversation condition and the 4 combined altered auditory feedback (AAF) conditions. No statistically significant differences in percentage of syllables stuttered were found in conversation or reading between the control conditions and the FAF/DAF or MAF conditions. The analysis of individual participants' data showed highly individual responsiveness to different conditions.
  
  
  CONCLUSIONS
  Participants' varying responses to differing AAF settings likely accounted for the failure to find group differences between conditions. These results suggest that studies that use standard DAF and FAF settings for all participants are likely to underestimate any AAF effect. It is not yet possible to predict who will benefit from AAF devices in everyday situations and the extent of those benefits.
authors.affiliation: Australian Stuttering Research Centre, The University of Sydney, Sydney, Australia.
authors.forename: Michelle
authors.initials: M
authors.lastname: Lincoln
authors.forename: Ann
authors.initials: A
authors.lastname: Packman
authors.forename: Mark
authors.initials: M
authors.lastname: Onslow
authors.forename: Mark
authors.initials: M
authors.lastname: Jones
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D056228:Feedback, Sensory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013065:Speech Intelligibility; D013067:Speech Perception; D013070:Speech Therapy / Q000379:methods*; D013342:Stuttering / Q000628:therapy*; D014705:Verbal Behavior; D055815:Young Adult