Stuttering inhibition via altered auditory feedback during scripted telephone conversations
Version of Record online: 30 AUG 2013
© 2013 Royal College of Speech and Language Therapists
International Journal of Language & Communication Disorders
Volume 49, Issue 1, pages 139–147, January-February 2014
How to Cite
Hudock, D. and Kalinowski, J. (2014), Stuttering inhibition via altered auditory feedback during scripted telephone conversations. International Journal of Language & Communication Disorders, 49: 139–147. doi: 10.1111/1460-6984.12053
- Issue online: 23 DEC 2013
- Version of Record online: 30 AUG 2013
- Manuscript Accepted: JUL 2013
- Manuscript Received: NOV 2012
Overt stuttering is inhibited by approximately 80% when people who stutter read aloud as they hear an altered form of their speech feedback to them. However, levels of stuttering inhibition vary from 60% to 100% depending on speaking situation and signal presentation. For example, binaural presentations of delayed auditory feedback (DAF) and frequency-altered feedback (FAF) have been shown to reduce stuttering by approximately 57% during scripted telephone conversations.
To examine stuttering frequency under monaural auditory feedback with one combination of DAF with FAF (COMBO-2) and two combinations of DAF with FAF (COMBO-4) during scripted telephone conversations.
Methods & Procedures
Nine adult participants who stutter called 15 local businesses during scripted telephone conversations; each condition consisted of five randomized telephone calls. Conditions consisted of (1) baseline (i.e. non-altered feedback), (2) COMBO-2 (i.e. 50-ms delay with a half octave spectral shift up), and (3) COMBO-4 (i.e. 200-ms delay and a half octave spectral shift down in addition to the COMBO-2). Participants wore a supra-aural headset with a dynamic condenser microphone while holding a receiver to their contralateral ear when making telephone calls.
Outcomes & Results
Stuttering was significantly reduced during both altered auditory feedback (AAF) conditions by approximately 65%. Furthermore, a greater reduction in stuttering was revealed during the COMBO with four effects (74%) as compared with the COMBO with two effects (63%).
Conclusions & Implications
Results from the current study support prior research reporting decreased stuttering under AAF during scripted telephone conversations. Findings that stuttering was significantly reduced to a greater extent under the COMBO with four effects condition suggest that second signals reduce stuttering along a continuum. Additionally, findings support prior research results of decreased stuttering frequency under AAF during hierarchically difficult speaking situations. Clinical application of these findings may be that people who stutter can use specific software or smartphone applications that produce second speech signals to inhibit stuttering frequency effectively during telephone conversations.