2008 Zemlin Award in Speech Sciences Memorial Lecture: The Role of Auditory Feedback for the Control of Voice Fundamental Frequency and Amplitude

Abstract

Abstract Previous research has failed to identify precise neural mechanisms involved in auditory feedback regulation of vocalization. The goal of this research project was to improve our understanding of neural mechanisms controlling the voice. Participants were instructed to sustain a vowel or repeat phrases during which perturbations in voice pitch or loudness feedback were presented. Voice signal averaging, neuroimaging, laryngeal electromyography, and cortical event-related potential techniques were used to measure vocal and neural responses to perturbed feedback. Pitch- and loudness-shifted voice feedback triggers small automatic corrective responses in voice fundamental frequency and amplitude during vowel or speech production. Larger responses during speech suggest task modulation of these responses. Larger responses were also recorded in individuals with Parkinson's disease and children with autism than in normal controls. Neural recording techniques revealed cortical activation during these responses. Cortical mechanisms are involved in generating corrective vocal responses to perturbations in voice auditory feedback. This system helps control the voice during speech and dynamically adjusts responses to meet vocal goals. Abnormally large responses in individuals with Parkinson's disease and autism suggest that the audio-vocal mechanisms just described may be involved in the speech and vocalizations of these individuals as well.