Language enables the acquisition of distinct sensorimotor memories for speech.

Interactions between the context in which a sensorimotor skill is learned and the recall of that memory have been primarily studied in limb movements, but speech production requires movement, and many aspects of speech processing are influenced by task-relevant contextual information. Here, in ecologically valid speech (read sentences), we test whether English-French bilinguals can use the language of production to acquire and recall distinct motor plans for similar speech sounds spanning the production workspace. Participants experienced real-time alterations of auditory feedback while producing interleaved English and French sentences.

Speech motor adaptation during synchronous and metronome-timed speech.

Sensorimotor integration during speech has been investigated by altering the sound of a speaker's voice in real time; in response, the speaker learns to change their production of speech sounds in order to compensate (adaptation). This line of research has however been predominantly limited to very simple speaking contexts, typically involving (a) repetitive production of single words and (b) production of speech while alone, without the usual exposure to other voices. This study investigated adaptation to a real-time perturbation of the first and second formants during production of sentences either in synchrony with a prerecorded voice (synchronous speech group) or alone (solo speech group).

Immediate cross-language transfer of novel articulatory plans in bilingual speech.

Current models of second language (L2) acquisition focus on interactions with a first language (L1) at the level of speech sound targets. In multilinguals, the degree of interaction between the articulatory plans that guide speech in each language remains unclear. Here, we directly address this question in bilingual speakers.

Auditory and Somatosensory Development for Speech in Later Childhood.

Purpose: This study collected measures of auditory-perceptual and oral somatosensory acuity in typically developing children and adolescents aged 9-15 years. We aimed to establish reference data that can be used as a point of comparison for individuals with residual speech sound disorder (RSSD), especially for RSSD affecting American English rhotics. We examined concurrent validity between tasks and hypothesized that performance on at least some tasks would show a significant association with age, reflecting ongoing refinement of sensory function in later childhood.

Early auditory responses to speech sounds in Parkinson's disease: preliminary data.

Parkinson's disease (PD), as a manifestation of basal ganglia dysfunction, is associated with a number of speech deficits, including reduced voice modulation and vocal output. Interestingly, previous work has shown that participants with PD show an increased feedback-driven motor response to unexpected fundamental frequency perturbations during speech production, and a heightened ability to detect differences in vocal pitch relative to control participants. Here, we explored one possible contributor to these enhanced responses.

Toward an index of oral somatosensory acuity: Comparison of three measures in adults.

Purpose: Somatosensory targets and feedback are instrumental in ensuring accurate speech production. Individuals differ in their ability to access and respond to somatosensory information, but there is no established standard for measuring somatosensory acuity. The primary objective of this study was to determine which of three measures of somatosensory acuity had the strongest association with change in production accuracy in a vowel learning task, while controlling for the better-studied covariate of auditory acuity.

Visual feedback of the tongue influences speech adaptation to a physical modification of the oral cavity.

Studies examining sensorimotor adaptation of speech to changing sensory conditions have demonstrated a central role for both auditory and somatosensory feedback in speech motor learning. The potential influence of visual feedback of oral articulators, which is not typically available during speech production but may nonetheless enhance oral motor control, remains poorly understood. The present study explores the influence of ultrasound visual feedback of the tongue on adaptation of speech production (focusing on the sound /s/) to a physical perturbation of the oral articulators (prosthesis altering the shape of the hard palate).

Exposure to Auditory Feedback Delay while Speaking Induces Perceptual Habituation but does not Mitigate the Disruptive Effect of Delay on Speech Auditory-motor Learning.

Perceiving the sensory consequences of our actions with a delay alters the interpretation of these afferent signals and impacts motor learning. For reaching movements, delayed visual feedback of hand position reduces the rate and extent of visuomotor adaptation, but substantial adaptation still occurs. Moreover, the detrimental effect of visual feedback delay on reach motor learning-selectively affecting its implicit component-can be mitigated by prior habituation to the delay.

Neural Correlates of Vocal Pitch Compensation in Individuals Who Stutter.

Stuttering is a disorder that impacts the smooth flow of speech production and is associated with a deficit in sensorimotor integration. In a previous experiment, individuals who stutter were able to vocally compensate for pitch shifts in their auditory feedback, but they exhibited more variability in the timing of their corrective responses. In the current study, we focused on the neural correlates of the task using functional MRI.

Sensorimotor adaptation across the speech production workspace in response to a palatal perturbation.

Talkers have been shown to adapt the production of multiple vowel sounds simultaneously in response to altered auditory feedback. The present study extends this work by exploring the adaptation of speech production to a physical alteration of the vocal tract involving a palatal prosthesis that impacts both somatosensory and auditory feedback during the production of a range of consonants and vowels. Acoustic and kinematic measures of the tongue were used to examine the impact of the physical perturbation across the various speech sounds, and to assess learned changes following 20 min of speech practice involving the production of complex, variable sentences.

Individual predictors of response to biofeedback training for second-language production.

While recent research suggests that visual biofeedback can facilitate speech production training in clinical populations and second language (L2) learners, individual learners' responsiveness to biofeedback is highly variable. This study investigated the hypothesis that the type of biofeedback provided, visual-acoustic versus ultrasound, could interact with individuals' acuity in auditory and somatosensory domains. Specifically, it was hypothesized that learners with lower acuity in a sensory domain would show greater learning in response to biofeedback targeting that domain.

The Relationship Between Speech Perceptual Discrimination and Speech Production in Parkinson's Disease.

Purpose We recently demonstrated that individuals with Parkinson's disease (PD) respond differentially to specific altered auditory feedback parameters during speech production. Participants with PD respond more robustly to pitch and less robustly to formant manipulations compared to control participants. In this study, we investigated whether differences in perceptual processing may in part underlie these compensatory differences in speech production.

Adults who stutter and metronome synchronization: evidence for a nonspeech timing deficit.

Speech timing deficits have been proposed as a causal factor in the disorder of stuttering. The question of whether individuals who stutter have deficits in nonspeech timing is one that has been revisited often, with conflicting results. Here, we uncover subtle differences in a manual metronome synchronization task that included tempo changes with adults who stutter and fluent speakers.

Different Responses to Altered Auditory Feedback in Younger and Older Adults Reflect Differences in Lexical Bias.

Purpose Previous work has found that both young and older adults exhibit a lexical bias in categorizing speech stimuli. In young adults, this has been argued to be an automatic influence of the lexicon on perceptual category boundaries. Older adults exhibit more top-down biases than younger adults, including an increased lexical bias.

Can perceptual training alter the effect of visual biofeedback in speech-motor learning?

Recent work showing that a period of perceptual training can modulate the magnitude of speech-motor learning in a perturbed auditory feedback task could inform clinical interventions or second-language training strategies. The present study investigated the influence of perceptual training on a clinically and pedagogically relevant task of vocally matching a visually presented speech target using visual-acoustic biofeedback. Forty female adults aged 18-35 yr received perceptual training targeting the English /æ-ɛ/ contrast, randomly assigned to a condition that shifted the perceptual boundary toward either /æ/ or /ɛ/.

Timing variability of sensorimotor integration during vocalization in individuals who stutter.

Persistent developmental stuttering affects close to 1% of adults and is thought to be a problem of sensorimotor integration. Previous research has demonstrated that individuals who stutter respond differently to changes in their auditory feedback while speaking. Here we explore a number of changes that accompany alterations in the feedback of pitch during vocal production.

Robust Sensorimotor Learning during Variable Sentence-Level Speech.

Sensorimotor learning has been studied by altering the sound of the voice in real time as speech is produced. In response to voice alterations, learned changes in production reduce the perceived auditory error and persist for some time after the alteration is removed [1-5]. The results of such experiments have led to the development of prominent models of speech production.

Auditory prediction during speaking and listening.

In the present EEG study, the role of auditory prediction in speech was explored through the comparison of auditory cortical responses during active speaking and passive listening to the same acoustic speech signals. Two manipulations of sensory prediction accuracy were used during the speaking task: (1) a real-time change in vowel F1 feedback (reducing prediction accuracy relative to unaltered feedback) and (2) presenting a stable auditory target rather than a visual cue to speak (enhancing auditory prediction accuracy during baseline productions, and potentially enhancing the perturbing effect of altered feedback). While subjects compensated for the F1 manipulation, no difference between the auditory-cue and visual-cue conditions were found.

Sensorimotor adaptation of whole-body postural control.

The aim of the present study was to examine the modification of postural symmetry during quiet standing using a sensorimotor adaptation paradigm. A group of neurologically typical adult participants performed a visually guided mediolateral (left-right) weight shifting task requiring precise adjustments in body orientation. During one phase of the task, the visual feedback of center of pressure (COP) was systematically biased toward the left or the right, requiring an adjustment in posture to compensate.

Sensorimotor control of vocal pitch and formant frequencies in Parkinson's disease.

Background: Auditory feedback reflects information on multiple speech parameters including fundamental frequency (pitch) and formant properties. Inducing auditory errors in these acoustic parameters during speech production has been used to examine the manner in which auditory feedback is integrated with ongoing speech motor processes. This integration has been shown to be impaired in disorders such as Parkinson's disease (PD), in which individuals exhibit difficulty adjusting to altered sensory-motor relationships.

Autophonic loudness perception in Parkinson's disease.

The relationship between the intensity and loudness of self-generated (autophonic) speech remains invariant despite changes in auditory feedback, indicating that non-auditory processes contribute to this form of perception. The aim of the current study was to determine if the speech perception deficit associated with Parkinson's disease may be linked to deficits in such processes. Loudness magnitude estimates were obtained from parkinsonian and non-parkinsonian subjects across four separate conditions: self-produced speech under normal, perturbed, and masked auditory feedback, as well as auditory presentation of pre-recorded speech (passive listening).

Please say what this word is-Vowel-extrinsic normalization in the sensorimotor control of speech.

The extent to which the adaptive nature of speech perception influences the acoustic targets underlying speech production is not well understood. For example, listeners can rapidly accommodate to talker-dependent phonetic properties-a process known as vowel-extrinsic normalization-without altering their speech output. Recent evidence, however, shows that reinforcement-based learning in vowel perception alters the processing of speech auditory feedback, impacting sensorimotor control during vowel production.

Auditory imagery forces motor action.

A large number of neuroimaging studies have investigated imagined sensory processing and motor behaviours. These studies have reported neural activation patterns for imagined processes that resemble those of real sensory and motor events. The widespread use of such methods has raised questions about the extent to which imagined sensorimotor events mimic their overt counterparts, including their ability to elicit sensorimotor interactions.

Plasticity in the human speech motor system drives changes in speech perception.

Recent studies of human speech motor learning suggest that learning is accompanied by changes in auditory perception. But what drives the perceptual change? Is it a consequence of changes in the motor system? Or is it a result of sensory inflow during learning? Here, subjects participated in a speech motor-learning task involving adaptation to altered auditory feedback and they were subsequently tested for perceptual change. In two separate experiments, involving two different auditory perceptual continua, we show that changes in the speech motor system that accompany learning drive changes in auditory speech perception.