Attenuation of vocal responses to pitch perturbations during Mandarin speech

Using altered auditory feedback to study pitch compensation and adaptation in tonal language speakers

Human speech production is strongly influenced by the auditory feedback it generates. Auditory feedback-what we hear when we speak-enables us to learn and maintain speaking skills and to rapidly correct errors in our speech. Over the last three decades, the real-time altered auditory feedback (AAF) paradigm has gained popularity as a tool to study auditory feedback control during speech production. This method involves changing a speaker's speech and feeding it back to them in near real time. More than 50% of the world's population speak tonal languages, in which the pitch or tone used to pronounce a word can change its meaning. This review article aims to offer an overview of the progression of AAF paradigm as a method to study pitch motor control among speakers of tonal languages. Eighteen studies were included in the current mini review and were compared based on their methodologies and results. Overall, findings from these studies provide evidence that tonal language speakers can compensate and adapt when receiving inconsistent and consistent pitch perturbations. Response magnitude and latency are influenced by a range of factors. Moreover, by combining AAF with brain stimulation and neuroimaging techniques, the neural basis of pitch motor control in tonal language speakers has been investigated. To sum up, AAF has been demonstrated to be an emerging tool for studying pitch motor control in speakers of tonal languages.

Controlling Pitch for Prosody: Sensorimotor Adaptation in Linguistically Meaningful Contexts

PURPOSE

This study examined how speakers adapt to fundamental frequency (fo) errors that affect the use of prosody to convey linguistic meaning, whether fo adaptation in that context relates to adaptation in linguistically neutral sustained vowels, and whether cue trading is reflected in responses in the prosodic cues of fo and amplitude.

METHOD

Twenty-four speakers said vowels and sentences while fo was digitally altered to induce predictable errors. Shifts in fo (±200 cents) were applied to the entire sustained vowel and one word (emphasized or unemphasized) in sentences. Two prosodic cues-fo and amplitude-were extracted. The effects of fo shifts, shift direction, and emphasis on fo response magnitude were evaluated with repeated-measures analyses of variance. Relationships between adaptive fo responses in sentences and vowels and between adaptive fo and amplitude responses were evaluated with Spearman correlations.

RESULTS

Speakers adapted to fo errors in both linguistically meaningful sentences and linguistically neutral vowels. Adaptive fo responses of unemphasized words were smaller than those of emphasized words when fo was shifted upward. There was no relationship between adaptive fo responses in vowels and emphasized words, but adaptive fo and amplitude responses were strongly, positively correlated.

CONCLUSIONS

Sensorimotor adaptation occurs in response to fo errors regardless of how disruptive the error is to linguistic meaning. Adaptation to fo errors during sustained vowels may not involve the exact same mechanisms as sensorimotor adaptation as it occurs in meaningful speech. The relationship between adaptive responses in fo and amplitude supports an integrated model of prosody.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25008908.

Modifications of auditory feedback and its effects on the voice of adult subjects: a scoping review

INTRODUCTION

The auditory perception of voice and its production involve auditory feedback, kinesthetic cues and the feedforward system that produce different effects for the voice. The Lombard, Sidetone and Pitch-Shift-Reflex effects are the most studied. The mapping of scientific experiments on changes in auditory feedback for voice motor control makes it possible to examine the existing literature on the phenomenon and may contribute to voice training or therapies.

PURPOSE

To map experiments and research results with manipulation of auditory feedback for voice motor control in adults.

METHOD

Scope review following the Checklist Preferred Reporting Items for Systematic reviews and Meta-Analyses extension (PRISMA-ScR) to answer the question: "What are the investigation methods and main research findings on the manipulation of auditory feedback in voice self-monitoring of adults?". The search protocol was based on the Population, Concept, and Context (PCC) mnemonic strategy, in which the population is adult individuals, the concept is the manipulation of auditory feedback and the context is on motor voice control. Articles were searched in the databases: BVS/Virtual Health Library, MEDLINE/Medical Literature Analysis and Retrieval System online, COCHRANE, CINAHL/Cumulative Index to Nursing and Allied Health Literature, SCOPUS and WEB OF SCIENCE.

RESULTS

60 articles were found, 19 on the Lombard Effect, 25 on the Pitch-shift-reflex effect, 12 on the Sidetone effect and four on the Sidetone/Lombard effect. The studies are in agreement that the insertion of a noise that masks the auditory feedback causes an increase in the individual's speech intensity and that the amplification of the auditory feedback promotes the reduction of the sound pressure level in the voice production. A reflex response to the change in pitch is observed in the auditory feedback, however, with particular characteristics in each study.

CONCLUSION

The material and method of the experiments are different, there are no standardizations in the tasks, the samples are varied and often reduced. The methodological diversity makes it difficult to generalize the results. The main findings of research on auditory feedback on voice motor control confirm that in the suppression of auditory feedback, the individual tends to increase the intensity of the voice. In auditory feedback amplification, the individual decreases the intensity and has greater control over the fundamental frequency, and in frequency manipulations, the individual tends to correct the manipulation. The few studies with dysphonic individuals show that they behave differently from non-dysphonic individuals.

Task-dependent pitch auditory feedback control in cerebellar ataxia

Purpose

The purpose of this study was to investigate how ataxia affects the task-dependent role of pitch auditory feedback control in speech. In previous research, individuals with ataxia produced over-corrected, hypermetric compensatory responses to unexpected pitch and formant frequency perturbations in auditory feedback in sustained vowels and single words (Houde et al., 2019; Li et al., 2019; Parrell et al., 2017). In this study, we investigated whether ataxia would also affect the task-dependent role of the auditory feedback control system, measuring whether pitch-shift responses would be mediated by speech task or semantic focus pattern as they are in neurologically healthy speakers.

Methods

Twenty-two adults with ataxia and 29 age- and sex-matched control participants produced sustained vowels and sentences with and without corrective focus while their auditory feedback was briefly and unexpectedly perturbed in pitch by +/-200 cents. The magnitude and latency of the reflexive pitch-shift responses were measured as a reflection of auditory feedback control.

Results

Individuals with ataxia produced larger reflexive pitch-shift responses in both the sustained-vowel and sentence-production tasks than the control participants. Additionally, a differential response magnitude was observed by task and sentence focus pattern for both groups.

Conclusion

These findings demonstrate that even though accuracy of auditory feedback control correction is affected by cerebellar damage, as evidenced by the hypermetric responses, the system still retains efficiency in utilizing the task-dependent role of auditory feedback.

Semantic focus mediates pitch auditory feedback control in phrasal prosody

This study investigated the effect of semantic focus on pitch auditory feedback control in the production of phrasal prosody through an experiment using pitch-shifted auditory feedback. We hypothesized that pitch-shift responses would be mediated by semantic focus because highly informative focus types, such as corrective focus, impose more specific constraints on the prosodic form of a phrase and require greater consistency in the production of pitch excursions compared to sentences with no such focus elements. Twenty-eight participants produced sentences with and without corrective focus while their auditory feedback was briefly and unexpectedly perturbed in pitch by +/-200 cents at the start of the sentence. The magnitude and latency of the reflexive pitch-shift responses were measured as a reflection of auditory feedback control. Our results matched our prediction that corrective focus would elicit larger pitch-shift responses, supporting our hypothesis that auditory feedback control is mediated by semantic focus.

Comparison of Involuntary and Volitional Responses to Pitch-Shifted Auditory Feedback: Evidence for Tone Speakers' Flexibility to Switch Between Opposing and Following Responses

PURPOSE

Our audio-vocal system involves a negative feedback system that functions to correct for fundamental frequency (f ₀) errors in production. Therefore, automatic and opposing responses appear when an unexpected change in voice pitch is present in auditory feedback. This study explores following responses to pitch perturbation in auditory feedback in tonal language speakers, which have been commonly overlooked or discarded by past research. We examine whether the number of response types (opposing vs. following) and their dynamic f ₀ contours in tone word production vary as a function of instruction (involuntary ["to ignore"] vs. volitional ["to compensate"]).

METHOD

Twenty-four native speakers of Taiwanese Southern Min (TSM) produced three disyllabic TSM words while receiving pitch perturbation through headphones. The three disyllabic words were tsau⁵⁵-im⁵⁵ ("out of tune"; HH), kau³³-uann³³ ("exchange"; MM), and pan¹¹-an¹¹ ("handle a case"; LL) that carry an identical high-, mid-, or low-level tone. The participants were instructed either "to ignore" or "to compensate" for the pitch shifts.

RESULTS

Results from a Bayesian Poisson regression show that the number of opposing and following responses were split nearly 50-50 for the "ignore" condition and 55%-35% for the "compensate" condition. The simulation results indicate that the speakers were able to switch between the feedback and the feedforward mode during the testing. On the other hand, f ₀ contour analyses using generalized additive models show that pitch-increasing responses (i.e., oppose to downshifts or follow upshifts) were significantly larger than pitch-decreasing responses (i.e., oppose to upshifts or follow downshifts) for the MM and LL words, but not for the HH word.

CONCLUSIONS

Our results provide support for the view that, for tone speakers, following responses are not uncommon. The magnitudes of pitch shift response trajectories have to do with the available pitch range for moving up or down in tone word production.

The effect of stimulus timing in compensating for pitch perturbation on flat, rising, and falling contours

The purpose of this study was to explore vocal responses to pitch perturbation on the flat, rising, and falling contour made of sequences of level tones in Taiwanese Southern Min. Twenty-two native speakers produced nine disyllabic words (flat: high-high, mid-mid, and low-low tone sequences; rising: mid-high, low-high, and low-mid tone sequences; falling: high-mid, high-low, and mid-low tone sequences). Pitch-shift stimuli (200 ms) appeared at either 100 ms (the beginning of the first syllable) or 400 ms (the beginning of the second syllable) after vocal onset. The participants were asked to ignore the pitch perturbation that appeared via auditory feedback. We found their compensation decreased when both syllables had identical level tones (i.e., the flat contour) but was particularly large when the overall contour was falling. Furthermore, pitch compensation at 100 ms was smaller than at 400 ms for the falling contour, but not for the flat and rising contours. Our results suggest that less susceptibility to pitch perturbation in the initial speech planning process is conditioned by the velocity of overall pitch contour.

Speech compensation responses and sensorimotor adaptation to formant feedback perturbations

Control of speech formants is important for the production of distinguishable speech sounds and is achieved with both feedback and learned feedforward control. However, it is unclear whether the learning of feedforward control involves the mechanisms of feedback control. Speakers have been shown to compensate for unpredictable transient mid-utterance perturbations of pitch and loudness feedback, demonstrating online feedback control of these speech features. To determine whether similar feedback control mechanisms exist in the production of formants, responses to unpredictable vowel formant feedback perturbations were examined. Results showed similar within-trial compensatory responses to formant perturbations that were presented at utterance onset and mid-utterance. The relationship between online feedback compensation to unpredictable formant perturbations and sensorimotor adaptation to consistent formant perturbations was further examined. Within-trial online compensation responses were not correlated with across-trial sensorimotor adaptation. A detailed analysis of within-trial time course dynamics across trials during sensorimotor adaptation revealed that across-trial sensorimotor adaptation responses did not result from an incorporation of within-trial compensation response. These findings suggest that online feedback compensation and sensorimotor adaptation are governed by distinct neural mechanisms. These findings have important implications for models of speech motor control in terms of how feedback and feedforward control mechanisms are implemented.

The Effect of Pitch Auditory Feedback Perturbations on the Production of Anticipatory Phrasal Prominence and Boundary

Purpose In this study, we investigated how the direction and timing of a perturbation in voice pitch auditory feedback during phrasal production modulated the magnitude and latency of the pitch-shift reflex as well as the scaling of acoustic production of anticipatory intonation targets for phrasal prominence and boundary. Method Brief pitch auditory feedback perturbations (±200 cents for 200-ms duration) were applied during the production of a target phrase on the first or the second word of the phrase. To replicate previous work, we first measured the magnitude and latency of the pitch-shift reflex as a function of the direction and timing of the perturbation within the phrase. As a novel approach, we also measured the adjustment in the production of the phrase-final prominent word as a function of perturbation direction and timing by extracting the acoustic correlates of pitch, loudness, and duration. Results The pitch-shift reflex was greater in magnitude after perturbations on the first word of the phrase, replicating the results from Mandarin speakers in an American English-speaking population. Additionally, the production of the phrase-final prominent word was acoustically enhanced (lengthened vowel duration and increased intensity and fundamental frequency) after perturbations earlier in the phrase, but more so after perturbations on the first word in the phrase. Conclusion The timing of the pitch perturbation within the phrase modulated both the magnitude of the pitch-shift reflex and the production of the prominent word, supporting our hypothesis that speakers use auditory feedback to correct for immediate production errors and to scale anticipatory intonation targets during phrasal production.

Modulation of auditory-vocal feedback control due to planned changes in voice fo

Previous studies have demonstrated that voice fundamental frequency (f_o), or pitch, relies on auditory feedback to monitor and correct for errors in production. When voice-pitch auditory feedback is unexpectedly perturbed, individuals typically produce a compensatory change in f_o that opposes the direction of the pitch-perturbation. Studies comparing steady vowel vocalizations and speech tasks have demonstrated task-dependent modulation of the compensatory response, but the effects of planning to volitionally change f_o during active vocalization have yet to be explored. Ten musicians and ten non-musicians were asked to perform two vocal tasks. Both tasks started off at a conversational f_o. In one task, pitch-shifted feedback was presented when the participants were planning to hold f_o constant (steady f_o), and in the other, feedback was shifted while participants were in the planning stage prior to raising f_o (raised f_o) from a steady state. Acoustical analyses of f_o were performed to measure the peak magnitude and latency of both the compensatory response as well as the voluntary f_o change. Results showed that planning to change pitch modulates the mechanisms controlling feedback-based error correction of f_o, and musicality affects how individuals incorporate modulations in auditory feedback with the feedforward plans to increase voice f_o.

Suppression of vocal responses to auditory perturbation with real-time visual feedback

Speakers can adjust pitch using auditory feedback through a short-latency corrective response known as the pitch-shift response (PSR). Suppression of the PSR denotes on-line stabilization of pitch. In this paper, the hypothesis that pitch-shift responses can be suppressed with real-time visual feedback of vocal F0 is investigated. Mandarin speakers and naive speakers without tonal language experience were instructed to produce the sustained vowel /a/ and Mandarin tone /ma1/ in an audio-only condition and a separate audio-visual condition. Both Mandarin speakers and naive speakers suppressed pitch-shift responses in the audio-visual condition, regardless of task (/a/ or /ma1/) and stimulus magnitude (25 cents or 200 cents). These findings suggest that multisensory feedback (audio-visual) can improve the stability of voice F0. The benefit of audio-visual integration is independent of language experience.

Training of Working Memory Impacts Neural Processing of Vocal Pitch Regulation

Working memory training can improve the performance of tasks that were not trained. Whether auditory-motor integration for voice control can benefit from working memory training, however, remains unclear. The present event-related potential (ERP) study examined the impact of working memory training on the auditory-motor processing of vocal pitch. Trained participants underwent adaptive working memory training using a digit span backwards paradigm, while control participants did not receive any training. Before and after training, both trained and control participants were exposed to frequency-altered auditory feedback while producing vocalizations. After training, trained participants exhibited significantly decreased N1 amplitudes and increased P2 amplitudes in response to pitch errors in voice auditory feedback. In addition, there was a significant positive correlation between the degree of improvement in working memory capacity and the post-pre difference in P2 amplitudes. Training-related changes in the vocal compensation, however, were not observed. There was no systematic change in either vocal or cortical responses for control participants. These findings provide evidence that working memory training impacts the cortical processing of feedback errors in vocal pitch regulation. This enhanced cortical processing may be the result of increased neural efficiency in the detection of pitch errors between the intended and actual feedback.

Principal component analysis reveals differential attentional modulation of the vocal response to pitch perturbation

The auditory-vocal system modifies voice fundamental frequency (F0) with auditory feedback. The responses to F0 changes in auditory feedback are known to depend on the task. The hypothesis explored in this study is that the task dependency is the result of multiple components of the F0 responses differently modulated with different tasks. Attention to audition was manipulated by task condition by the instruction to ignore or to count the number of the F0 shifts heard during vocalization. A synthetic voice with pitch shifts was used as auditory pseudo-feedback. The upward and downward shifts evoked very similar vocal F0 response patterns with polarity reversal. Attention to the auditory feedback caused a reduction in the grand-average response amplitude. By decomposing the F0 responses with principal component analysis (PCA), three principal components (PCs) with different peak latencies were found to have contributions above the criterion of 5%, totaling to 74%. All three PCs contributed to a compensatory response under the "ignore" condition. The slowest PC changed its polarity and the intermediate PC was reduced to almost zero under the "count" condition. Thus, the task-dependency of the F0 response to auditory feedback can be described in terms of different sensitivities of components to attention.

ERP correlates of language-specific processing of auditory pitch feedback during self-vocalization

The present study investigated whether the neural correlates for auditory feedback control of vocal pitch can be shaped by tone language experience. Event-related potentials (P2/N1) were recorded from adult native speakers of Mandarin and Cantonese who heard their voice auditory feedback shifted in pitch by -50, -100, -200, or -500 cents when they sustained the vowel sound /u/. Cantonese speakers produced larger P2 amplitudes to -200 or -500 cents stimuli than Mandarin speakers, but this language effect failed to reach significance in the case of -50 or -100 cents. Moreover, Mandarin speakers produced shorter N1 latencies over the left hemisphere than the right hemisphere, whereas Cantonese speakers did not. These findings demonstrate that neural processing of auditory pitch feedback in vocal motor control is subject to language-dependent neural plasticity, suggesting that cortical mechanisms of auditory-vocal integration can be shaped by tone language experience.

Vocal responses to perturbations in voice auditory feedback in individuals with Parkinson's disease

BACKGROUND

One of the most common symptoms of speech deficits in individuals with Parkinson's disease (PD) is significantly reduced vocal loudness and pitch range. The present study investigated whether abnormal vocalizations in individuals with PD are related to sensory processing of voice auditory feedback. Perturbations in loudness or pitch of voice auditory feedback are known to elicit short latency, compensatory responses in voice amplitude or fundamental frequency.

METHODOLOGY/PRINCIPAL FINDINGS

Twelve individuals with Parkinson's disease and 13 age- and sex-matched healthy control subjects sustained a vowel sound (/α/) and received unexpected, brief (200 ms) perturbations in voice loudness (±3 or 6 dB) or pitch (±100 cents) auditory feedback. Results showed that, while all subjects produced compensatory responses in their voice amplitude or fundamental frequency, individuals with PD exhibited larger response magnitudes than the control subjects. Furthermore, for loudness-shifted feedback, upward stimuli resulted in shorter response latencies than downward stimuli in the control subjects but not in individuals with PD.

CONCLUSIONS/SIGNIFICANCE

The larger response magnitudes in individuals with PD compared with the control subjects suggest that processing of voice auditory feedback is abnormal in PD. Although the precise mechanisms of the voice feedback processing are unknown, results of this study suggest that abnormal voice control in individuals with PD may be related to dysfunctional mechanisms of error detection or correction in sensory feedback processing.

Differential effects of perturbation direction and magnitude on the neural processing of voice pitch feedback

OBJECTIVE

The present study examined the differential effects of voice auditory feedback perturbation direction and magnitude on voice fundamental frequency (F(0)) responses and event-related potentials (ERPs) from EEG electrodes on the scalp.

METHODS

The voice F(0) responses and N1 and P2 components of ERPs were examined from 12 right-handed speakers when they sustained a vowel phonation and their mid-utterance voice pitch feedback was shifted ±100, ±200, and ±500 cents with 200 ms duration.

RESULTS

Downward voice pitch feedback perturbations led to larger voice F(0) responses than upward perturbations. The amplitudes of N1 and P2 components were larger for downward compared with upward pitch-shifts for 200 and 500 cents stimulus magnitudes. Shorter N1 and P2 latencies were also associated with larger magnitudes of pitch feedback perturbations.

CONCLUSIONS

Corresponding changes in vocal and neural responses to upward and downward voice pitch feedback perturbations suggest that the N1 and P2 components of ERPs reflect neural concomitants of the vocal responses.

SIGNIFICANCE

The findings of interactive effects between the magnitude and direction of voice feedback pitch perturbation on N1 and P2 ERP components indicate that the neural mechanisms underlying error detection and correction in voice pitch auditory feedback are differentially sensitive to both the magnitude and direction of pitch perturbations.

Effect of tonal native language on voice fundamental frequency responses to pitch feedback perturbations during sustained vocalizations

The purpose of this cross-language study was to examine whether the online control of voice fundamental frequency (F(0)) during vowel phonation is influenced by language experience. Native speakers of Cantonese and Mandarin, both tonal languages spoken in China, participated in the experiments. Subjects were asked to vocalize a vowel sound /u/at their comfortable habitual F(0), during which their voice pitch was unexpectedly shifted (± 50, ± 100, ± 200, or ± 500 cents, 200 ms duration) and fed back instantaneously to them over headphones. The results showed that Cantonese speakers produced significantly smaller responses than Mandarin speakers when the stimulus magnitude varied from 200 to 500 cents. Further, response magnitudes decreased along with the increase in stimulus magnitude in Cantonese speakers, which was not observed in Mandarin speakers. These findings suggest that online control of voice F(0) during vocalization is sensitive to language experience. Further, systematic modulations of vocal responses across stimulus magnitude were observed in Cantonese speakers but not in Mandarin speakers, which indicates that this highly automatic feedback mechanism is sensitive to the specific tonal system of each language.

Sex-related differences in vocal responses to pitch feedback perturbations during sustained vocalization

The present study assessed the effect of sex on voice fundamental frequency (F(0)) responses to pitch feedback perturbations during sustained vocalization. Sixty-four native-Mandarin speakers heard their voice pitch feedback shifted at ± 50, ± 100, or ± 200 cents for 200 ms, five times during each vocalization. The results showed that, as compared to female speakers, male speakers produced significantly larger but slower vocal responses to the pitch-shifted stimuli. These findings reveal a modulation of vocal response as a function of sex, and suggest that there may be a differential processing of vocal pitch feedback perturbations between men and women.

Effect of tonal native language on voice fundamental frequency responses to pitch feedback perturbations during sustained vocalizations

The purpose of this cross-language study was to examine whether the online control of voice fundamental frequency (F(0)) during vowel phonation is influenced by language experience. Native speakers of Cantonese and Mandarin, both tonal languages spoken in China, participated in the experiments. Subjects were asked to vocalize a vowel sound /u/at their comfortable habitual F(0), during which their voice pitch was unexpectedly shifted (± 50, ± 100, ± 200, or ± 500 cents, 200 ms duration) and fed back instantaneously to them over headphones. The results showed that Cantonese speakers produced significantly smaller responses than Mandarin speakers when the stimulus magnitude varied from 200 to 500 cents. Further, response magnitudes decreased along with the increase in stimulus magnitude in Cantonese speakers, which was not observed in Mandarin speakers. These findings suggest that online control of voice F(0) during vocalization is sensitive to language experience. Further, systematic modulations of vocal responses across stimulus magnitude were observed in Cantonese speakers but not in Mandarin speakers, which indicates that this highly automatic feedback mechanism is sensitive to the specific tonal system of each language.

Adaptive auditory feedback control of the production of formant trajectories in the Mandarin triphthong /iau/ and its pattern of generalization

In order to test whether auditory feedback is involved in the planning of complex articulatory gestures in time-varying phonemes, the current study examined native Mandarin speakers' responses to auditory perturbations of their auditory feedback of the trajectory of the first formant frequency during their production of the triphthong /iau/. On average, subjects adaptively adjusted their productions to partially compensate for the perturbations in auditory feedback. This result indicates that auditory feedback control of speech movements is not restricted to quasi-static gestures in monophthongs as found in previous studies, but also extends to time-varying gestures. To probe the internal structure of the mechanisms of auditory-motor transformations, the pattern of generalization of the adaptation learned on the triphthong /iau/ to other vowels with different temporal and spatial characteristics (produced only under masking noise) was tested. A broad but weak pattern of generalization was observed; the strength of the generalization diminished with increasing dissimilarity from /iau/. The details and implications of the pattern of generalization are examined and discussed in light of previous sensorimotor adaptation studies of both speech and limb motor control and a neurocomputational model of speech motor control.

Age-related differences in vocal responses to pitch feedback perturbations: a preliminary study

The present study tested the effect of age on voice fundamental frequency (F(0)) responses to pitch-shifted feedback. Pitch-shift stimuli (-100 cents, 200 ms duration) were presented to 30 native-English speakers: 10 children (7-12 yrs), 10 younger adults (19-21 yrs), and 10 older adults (60-73 yrs). Significantly larger response magnitudes were found in the older group compared to the children and young adult groups, while the longest latencies were associated with the children group as compared to the two adult groups. These findings provide preliminary evidence of an age effect on the modulation of vocal responses to pitch-shifted feedback.

Voice fundamental frequency modulates vocal response to pitch perturbations during English speech

Previous research has demonstrated task-dependent vocal responses to pitch perturbations during speech production. The present study investigated the effect of voice fundamental frequency (F(0)) on the modulation of vocal responses during English speech. Randomized pitch shifts of +/-100 or 200 cents during speaking were presented to English speakers. Results indicated larger vocal responses and shorter latencies at a high voice F(0) than at a low voice F(0), but no significance differences were observed for stimulus magnitude or direction. These findings suggest that the pitch-shift reflex during speech can be modulated as a function of voice F(0).