Speaking speed effects on delayed auditory feedback disruption of speech fluency

Area of Science:

• Neuroscience
• Speech Science
• Cognitive Psychology

Background:

• Auditory feedback is crucial for speech production.
• Delayed auditory feedback (DAF) is known to disrupt speech fluency.
• The influence of speaking rate and hemispheric processing on DAF effects requires further investigation.

Purpose of the Study:

• To investigate the effects of delayed auditory feedback on verbal fluency at varying speaking rates and auditory input laterality.
• To explore the role of central vs. peripheral mechanisms and hemispheric specialization in response to DAF.

Main Methods:

• 24 Italian medical students performed verbal fluency tasks under normal and delayed auditory feedback (200 msec delay).
• Experiments involved bilateral, right-ear, and left-ear auditory input across normal and increased speaking rates.
• Speech errors were quantified across six different experimental conditions.

Main Results:

• DAF significantly disrupted speech at normal speaking rates.
• Increased speaking rates reduced the disruptive effects of DAF, although error rates remained higher with DAF.
• Speech disruption was more pronounced with auditory input to the right ear (left hemisphere), indicating greater left hemisphere susceptibility to DAF.

Conclusions:

• Increased speaking rates may shift speech production reliance towards more central processing mechanisms, mitigating DAF effects.
• Hemispheric specialization, particularly the left hemisphere's role in linguistic processing, may explain its heightened susceptibility to DAF.
• These findings contribute to understanding the neural underpinnings of speech production and auditory feedback processing.