Auditory Feedback Control of Vocal Pitch during Sustained Vocalization: A Cross-Sectional Study of Adult Aging

Paul L Gribble,Peng Liu,Dongfeng Huang,Jeffery A Jones,Zhaocong Chen,Hanjun Liu

doi:10.1371/journal.pone.0022791

Abstract

BackgroundAuditory feedback has been demonstrated to play an important role in the control of voice fundamental frequency (F0), but the mechanisms underlying the processing of auditory feedback remain poorly understood. It has been well documented that young adults can use auditory feedback to stabilize their voice F0 by making compensatory responses to perturbations they hear in their vocal pitch feedback. However, little is known about the effects of aging on the processing of audio-vocal feedback during vocalization.Methodology/Principal FindingsIn the present study, we recruited adults who were between 19 and 75 years of age and divided them into five age groups. Using a pitch-shift paradigm, the pitch of their vocal feedback was unexpectedly shifted ±50 or ±100 cents during sustained vocalization of the vowel sound/u/. Compensatory vocal F0 response magnitudes and latencies to pitch feedback perturbations were examined. A significant effect of age was found such that response magnitudes increased with increasing age until maximal values were reached for adults 51–60 years of age and then decreased for adults 61–75 years of age. Adults 51–60 years of age were also more sensitive to the direction and magnitude of the pitch feedback perturbations compared to younger adults.ConclusionThese findings demonstrate that the pitch-shift reflex systematically changes across the adult lifespan. Understanding aging-related changes to the role of auditory feedback is critically important for our theoretical understanding of speech production and the clinical applications of that knowledge.

Highlights

During vocal communication, the fundamental frequency (F0) of one’s voice is used to convey a large range of social information such as the emotional state of the speaker, whether an utterance is a statement or a question, and whether the speaker is being sarcastic or emphatic
These findings demonstrate that the pitch-shift reflex systematically changes across the adult lifespan
Understanding aging-related changes to the role of auditory feedback is critically important for our theoretical understanding of speech production and the clinical applications of that knowledge

Summary

Introduction

The fundamental frequency (F0) of one’s voice is used to convey a large range of social information such as the emotional state of the speaker, whether an utterance is a statement or a question, and whether the speaker is being sarcastic or emphatic. A number of researchers have explored the role of auditory feedback in voice F0 control by exposing speakers to altered versions of their feedback [1,7,8,9,10,11] During these experiments, the participants were asked to vocalize a vowel sound or a speech syllable while they heard their voice pitch unexpectedly altered in an upward or downward direction. It has been suggested that this response is reflexive because subjects seem to be unaware that they are changing their voice F0 so rapidly (,100 ms) [8]; it is termed the pitch-shift reflex This direction-specific vocal response to a pitch-shifted stimulus indicates that the audio-vocal system detects the direction of the pitch perturbation in auditory feedback, and adjusts the response . Little is known about the effects of aging on the processing of audio-vocal feedback during vocalization

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Discussion

Conclusion