Speech-Induced Suppression for Delayed Auditory Feedback in Adults Who Do and Do Not Stutter

Area of Science:

• Neuroscience
• Speech and Hearing Science
• Auditory Processing

Background:

• Speech-induced suppression is a normal reduction in auditory evoked potentials for self-generated speech.
• It is unclear if individuals who stutter exhibit typical auditory modulation during speech production.
• Previous research on auditory processing in stuttering has yielded conflicting results.

Purpose of the Study:

• To investigate auditory evoked potentials (N1 component) in response to self-generated speech versus listening to recorded speech.
• To examine the effects of delayed auditory feedback (DAF) on speech-induced suppression in fluent speakers and adults who stutter.
• To explore potential differences in auditory modulation mechanisms between fluent speakers and those who stutter.

Main Methods:

• Compared auditory evoked potentials (N1) in a Speaking condition (own voice with DAF) and a Listening condition (recorded own voice with DAF).
• Utilized DAF at 100 ms, 200 ms, 500 ms, and 1,000 ms.
• Recruited 24 normally-fluent speakers and 16 adults who stutter.

Main Results:

• Fluent speakers showed enhanced suppression of auditory evoked potentials with shorter DAF times (100 ms, 200 ms).
• Adults who stutter did not exhibit the same opposing changes in Speaking and Listening conditions as fluent speakers.
• Significant speech-induced suppression was observed in adults who stutter only at 200 ms DAF, with greater suppression correlating with stuttering severity.

Conclusions:

• Delayed auditory feedback methods may reveal insights into auditory modulation in stuttering.
• Individuals who stutter may have atypical auditory processing related to self-monitoring of speech.
• Further research is needed to fully understand the neural basis of auditory-speech interactions in stuttering.