Influence of Altered Auditory Feedback on Oral-Nasal Balance in Speech

This study explored the role of auditory feedback in the regulation of oral-nasal balance in speech.

Twenty typical female speakers wore a Nasometer 6450 (KayPentax) headset and headphones while continuously repeating a sentence with oral and nasal sounds. Oral-nasal balance was quantified with nasalance scores. The signals from 2 additional oral and nasal microphones were played back to the participants through the headphones. The relative loudness of the nasal channel in the mix was gradually changed so that the speakers heard themselves as more or less nasal. An additional amplitude control group of 9 female speakers completed the same task while hearing themselves louder or softer in the headphones.

A repeated-measures analysis of variance of the mean nasalance scores of the stimulus sentence at baseline, minimum, and maximum nasal feedback conditions demonstrated a significant effect of the nasal feedback condition. Post hoc analyses found that the mean nasalance scores were lowest for the maximum nasal feedback condition. The scores of the minimum nasal feedback condition were significantly higher than 2 of the 3 baseline feedback conditions. The amplitude control group did not show any effects of volume changes on nasalance scores.

Increased nasal feedback led to a compensatory adjustment in the opposite direction, confirming that oral-nasal balance is regulated by auditory feedback. However, a lack of nasal feedback did not lead to a consistent compensatory response of similar magnitude.