Vocal and Neural Responses to Unexpected Changes in Voice Pitch Auditory Feedback During Register Transitions

Abstract

Objective/Hypothesis It is known that singers are able to control their voice to maintain a relatively constant vocal quality while transitioning between vocal registers; however, the neural mechanisms underlying this effect are not understood. It was hypothesized that greater attention to the acoustical feedback of the voice and increased control of the vocal musculature during register transitions compared to singing within a register would be represented as neurological differences in event-related potentials (ERPs). Study Design/Methods Nine singers sang musical notes at the high end of the modal register (the boundary between the modal and head/falsetto registers) and at the low end (the boundary between the modal and fry/pulse registers). While singing, the pitch of the voice auditory feedback was unexpectedly shifted either into the adjacent register (“toward” the register boundary) or within the modal register (“away from” the boundary). Singers were instructed to maintain a constant pitch and ignore any changes to their voice feedback. Results Vocal response latencies and magnitude of the accompanying N1 and P2 ERPs were greatest at the lower (modal-fry) boundary when the pitch shift carried the subjects’ voices into the fry register as opposed to remaining within the modal register. Conclusions These findings suggest that when a singer lowers the pitch of their voice such that it enters the fry register from the modal register, there is increased sensory-motor control of the voice, reflected as increased magnitude of the neural potentials to help minimize qualitative changes in the voice.

Objective measurement of pitch extractors' responses to frequency modulated sounds and two reference pitch extraction methods for analyzing voice pitch responses to auditory stimulation

“…The combination of elements test signal generator, response analyser, and CAPRICEP-set and orthogonal matrix is the CAPRICEP-based method [3]. We used a Gaussian smoother 8 for LPF and fed the output to VFO (Variable Frequency Oscillator) to modulate fo of the test signals. We normalize the pitch extractor's responses by the LTI response of the lower path in Fig.…”

“…The first author introduced an altered auditory feedback technique 5 and reported that our voice pitch control consists of two responses to feedback pitch modification, the voluntary and the involuntary responses a quarter-century ago [5,6]. Despite decades of research, altered feedback still is a hot topic for investigating speech chain and underlying neural basis [7][8][9][10][11]. This research mainly focused on voluntary responses represented by the pitch shift paradigm and adaptation paradigm [12][13][14].…”

“…We used an ad hoc workaround 8. We used a sidelobe-less Gaussian window by setting the endpoint level to the machine epsilon.…”

An objective test tool for pitch extractors' response attributes

“…The first author introduced an altered auditory feed-back technique 1 and reported that our voice fundamental frequency (fo) 2 responds to feedback pitch modification [4]. Despite decades of research, altered feedback still is a hot topic for investigating speech chain and underlying neural basis [5][6][7][8][9]. Those research focused on voluntary responses represented by the pitch shift paradigm and adaptation paradigm [10,11].…”

Mixture of orthogonal sequences made from extended time-stretched pulses enables measurement of involuntary voice fundamental frequency response to pitch perturbation

“…The fundamental frequency (fo) 1 of sustained vowels respond to frequency modulation of aurally presented sounds [2][3][4]. This response, combined with our recently developed system analysis method [5,6] provides a versatile new tool for investigating the auditory-to-speech chain.…”