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Camera Mouse is a freely available software program that visually tracks the movement of facial features to allow individuals with motor impairments to control a computer mouse. The goal of this case study was to provide an evaluation of Camera Mouse as a computer access method as part of a multiple modality communication system for an individual with cerebral palsy. The participant was asked to reproduce sentences and respond to ethical dilemmas for language sampling. Tasks were completed using natural speech and an AAC solution consisting of Camera Mouse paired with an orthographic selection interface and speech synthesis. The participant completed a questionnaire for satisfaction with the introduced assistive technology. Camera Mouse resulted in higher intelligibility than natural speech, while natural speech had a higher rate. She used more complex language with her natural speech. The participant rated Camera Mouse as at least 3/5 on all measures, including 5/5 on weight and safety. The results of this case study suggest Camera Mouse is a promising computer access system for communication supported by the participant's satisfaction rating, expressive language, and synthesized speech production capabilities. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to quantify sentence-level articulatory kinematics in individuals treated for oral squamous cell carcinoma (ITOC) compared to control speakers while also assessing the effect of treatment site (jaw vs. tongue). Furthermore, this study aimed to assess the relation between articulatory-kinematic measures and self-reported speech problems. Method: Articulatory-kinematic data from the tongue tip, tongue back, and jaw were collected using electromagnetic articulography in nine Dutch ITOC and eight control speakers. To quantify articulatory kinematics, the two-dimensional articulatory working space (AWS; in mm² ), one-dimensional anteroposterior range of motion (AP-ROM; in mm), and superior-inferior range of motion (SIROM in mm) were calculated and examined. Self-reported speech problems were assessed with the Speech Handicap Index (SHI). Results: Compared to a sex-matched control group, ITOC showed significantly smaller AWS, AP-ROM, and SI-ROM for both the tongue tip and tongue back sensor, but no significant differences were observed for the jaw sensor. This pattern was found for both individuals treated for tongue and jaw tumors. Moderate nonsignificant correlations were found between the SHI and the AWS of the tongue back and jaw sensors. Conclusions: Despite large individual variation, ITOC showed reduced one- and two-dimensional tongue, but not jaw, movements compared to control speakers and treatment for tongue and jaw tumors resulted in smaller tongue movements. A larger sample size is needed to establish a more generalizable connection between the AWS and the SHI. Further research should explore how these kinematic changes in ITOC are related to acoustic and perceptual measures of speech. [ABSTRACT FROM AUTHOR]

Purpose: Behavioral assays of feedforward and feedback auditory–motor control of voice and articulation frequently are used to make inferences about underlying neural mechanisms and to study speech development and disorders. However, no studies have examined the test–retest reliability of such measures, which is critical for rigorous study of auditory–motor control. Thus, the purpose of the present study was to assess the reliability of assays of feedforward and feedback control in voice versus articulation domains. Method: Twenty-eight participants (14 cisgender women, 12 cisgender men, one transgender man, one transmasculine/nonbinary) who denied any history of speech, hearing, or neurological impairment were measured for responses to predictable versus unexpected auditory feedback perturbations of vocal (fundamental frequency, fo) and articulatory (first formant, F1) acoustic parameters twice, with 3–6 weeks between sessions. Reliability was measured with intraclass correlations. Results: Opposite patterns of reliability were observed for fo and F1; fo reflexive responses showed good reliability and fo adaptive responses showed poor reliability, whereas F1 reflexive responses showed poor reliability and F1 adaptive responses showed moderate reliability. However, a criterion-referenced categorical measurement of fo adaptive responses as typical versus atypical showed substantial test–retest agreement. Conclusions: Individual responses to some behavioral assays of auditory–motor control of speech should be interpreted with caution, which has implications for several fields of research. Additional research is needed to establish reliable criterion-referenced measures of F1 adaptive responses as well as fo and F1 reflexive responses. Furthermore, the opposite patterns of test–retest reliability observed for voice versus articulation add to growing evidence for differences in underlying neural control mechanisms. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to determine the effect of a concurrent working memory task on acoustic measures of speech in individuals with Parkinson's disease (PD). Method: Individuals with PD and age- and sex-matched controls performed a speaking task with and without a Stroop-like concurrent working memory task. Cepstral peak prominence, low-to-high spectral energy ratio, fundamental frequency (fo) standard deviation, articulation rate, pause duration, articulatory-acoustic vowel space, relative fo, mean voice onset time (VOT), and VOT variability were calculated for each condition. Mixed-model analyses of variance were performed to determine the effects of group, condition (presence of the concurrent working memory task), and their interaction on the acoustic measures. Results: All measures except for VOT variability, mean pause duration, and relative fo offset differed between people with and without PD. Cepstral peak prominence, articulation rate, and relative fo offset differed as a function of condition. However, no measures indicated disparate effects of condition as a function of group. Conclusion: Although differentially impactful on limb motor function in PD, here a concurrent working memory task was not found to be differentially disruptive to speech acoustics in PD. [ABSTRACT FROM AUTHOR]

Purpose: The practice of removing “following” responses from speech perturbation analyses is increasingly common, despite no clear evidence as to whether these responses represent a unique response type. This study aimed to determine if the distribution of responses to auditory perturbation paradigms represents a bimodal distribution, consisting of two distinct response types, or a unimodal distribution. Method: This mega-analysis pooled data from 22 previous studies to examine the distribution and magnitude of responses to auditory perturbations across four tasks: adaptive pitch, adaptive formant, reflexive pitch, and reflexive formant. Data included at least 150 unique participants for each task, with studies comprising younger adult, older adult, and Parkinson’s disease populations. A Silverman’s unimodality test followed by a smoothed bootstrap resampling technique was performed for each task to evaluate the number of modes in each distribution. Wilcoxon signed-ranks tests were also performed for each distribution to confirm significant compensation in response to the perturbation. Results: Modality analyses were not significant (p > .05) for any group or task, indicating unimodal distributions. Our analyses also confirmed compensatory reflexive responses to pitch and formant perturbations across all groups, as well as adaptive responses to sustained formant perturbations. However, analyses of sustained pitch perturbations only revealed evidence of adaptation in studies with younger adults. Conclusion: The demonstration of a clear unimodal distribution across all tasks suggests that following responses do not represent a distinct response pattern, but rather the tail of a unimodal distribution. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to determine normative values for cepstral peak prominence measures across the life span as a function of sex using clinically relevant stimuli (/ɑ/, /i/, and two sentences of The Rainbow Passage) and two commonly used software types: Praat (Version 6.0.50) and Analysis of Dysphonia in Speech and Voice (ADSV). Method: One hundred fifty speakers (75 males, 75 females; evenly distributed into three age groups) without voice disorders aged 18–91 years were recorded via headset microphone in a sound-treated booth. Cepstral measures were analyzed using common analysis methods in Praat and ADSV by sex, stimuli, and software type. Kruskal–Wallis tests and post hoc Mood’s Median tests for significant factors were performed on cepstral measures to assess the effects of age group, sex, stimuli, and software type. Results: The results revealed statistically significant effects of sex, stimuli, and software type on cepstral measures, but no statistical effect of age group on cepstral values. Females had lower average cepstral values compared to males. Across stimuli, the highest average cepstral measure was found for sustained /ɑ/, followed by sustained /i/, and then of the two sentences of The Rainbow Passage. Average cepstral measures in Praat were higher than those from ADSV. Conclusions: The current work did not find a statistical effect of age group on cepstral values; thus, normative cepstral values were reported by sex, stimuli, and software type. Future work should examine the applicability of these normative values for discriminating speakers with and without voice disorders. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this study was to examine the effects of increases in vocal effort, without changing speech intensity, on respiratory and articulatory kinematics in young adults with typical voices. Method: A total of 10 participants completed a reading task under three speaking conditions: baseline, mild vocal effort, and maximum vocal effort. Respiratory inductance plethysmography bands around the chest and abdomen were used to estimate lung volumes during speech, and sensor coils for electromagnetic articulography were used to transduce articulatory movements, resulting in the following outcome measures: lung volume at speech initiation (LVSI) and at speech termination (LVST), articulatory kinematic vowel space (AKVS) of two points on the tongue dorsum (body and blade), and lip aperture. Results: With increases in vocal effort, and no statistical changes in speech intensity, speakers showed: (a) no statistically significant differences in LVST, (b) statistically significant increases in LVSI, (c) no statistically significant differences in AKVS measures, and (d) statistically significant reductions in lip aperture. Conclusions: Speakers with typical voices exhibited larger lung volumes at speech initiation during increases in vocal effort, paired with reduced lip displacements. To our knowledge, this is the first study to demonstrate evidence that articulatory kinematics are impacted by modulations in vocal effort. However, the mechanisms underlying vocal effort may differ between speakers with and without voice disorders. Thus, future work should examine the relationship between articulatory kinematics, respiratory kinematics, and laryngeal-level changes during vocal effort in speakers with and without voice disorders. [ABSTRACT FROM AUTHOR]

Purpose: Unexpected and sustained manipulations of auditory feedback during speech production result in "reflexive" and "adaptive" responses, which can shed light on feedback and feedforward auditory-motor control processes, respectively. Persons with Parkinson's disease (PwPD) have shown aberrant reflexive and adaptive responses, but responses appear to differ for control of vocal and articulatory features. However, these responses have not been examined for both voice and articulation in the same speakers and with respect to auditory acuity and functional speech outcomes (speech intelligibility and naturalness). Method: Here, 28 PwPD on their typical dopaminergic medication schedule and 28 age-, sex-, and hearing-matched controls completed tasks yielding reflexive and adaptive responses as well as auditory acuity for both vocal and articulatory features. Results: No group differences were found for any measures of auditory-motor control, conflicting with prior findings in PwPD while off medication. Auditory-motor measures were also compared with listener ratings of speech function: first formant frequency acuity was related to speech intelligibility, whereas adaptive responses to vocal fundamental frequency manipulations were related to speech naturalness. Conclusions: These results support that auditory-motor processes for both voice and articulatory features are intact for PwPD receiving medication. This work is also the first to suggest associations between measures of auditorymotor control and speech intelligibility and naturalness. [ABSTRACT FROM AUTHOR]

Hyperfunctional voice disorders (HVDs) are the most common class of voice disorders, consisting of diagnoses such as vocal fold nodules and muscle tension dysphonia. These speech production disorders result in effort, fatigue, pain, and even complete loss of voice. The mechanisms underlying HVDs are largely unknown. Here, the auditory-motor control of voice fundamental frequency (fo) was examined in 62 speakers with and 62 speakers without HVDs. Due to the high prevalence of HVDs in singers, and the known impacts of singing experience on auditory-motor function, groups were matched for singing experience. Speakers completed three tasks, yielding: (1) auditory discrimination of voice fo; (2) reflexive responses to sudden fo shifts; and (3) adaptive responses to sustained fo shifts. Compared to controls, and regardless of singing experience, individuals with HVDs showed: (1) worse auditory discrimination; (2) comparable reflexive responses; and (3) a greater frequency of atypical adaptive responses. Atypical adaptive responses were associated with poorer auditory discrimination, directly implicating auditory function in this motor disorder. These findings motivate a paradigm shift for understanding development and treatment of HVDs. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to explore the relationship between feedback and feedforward control of articulation and voice by measuring reflexive and adaptive responses to first formant (F1) and fundamental frequency (fo) perturbations. In addition, perception of F1 and fo perturbation was estimated using passive (listening) and active (speaking) just noticeable difference paradigms to assess the relation of auditory acuity to reflexive and adaptive responses. Method: Twenty healthy women produced single words and sustained vowels while the F1 or fo of their auditory feedback was suddenly and unpredictably perturbed to assess reflexive responses or gradually and predictably perturbed to assess adaptive responses. Results: Typical speakers' reflexive responses to sudden perturbation of F1 were related to their adaptive responses to gradual perturbation of F1. Specifically, speakers with larger reflexive responses to sudden perturbation of F1 had larger adaptive responses to gradual perturbation of F1. Furthermore, their reflexive responses to sudden perturbation of F1 were associated with their passive auditory acuity to F1 such that speakers with better auditory acuity to F1 produced larger reflexive responses to sudden perturbations of F1. Typical speakers' adaptive responses to gradual perturbation of F1 were not associated with their auditory acuity to F1. Speakers' reflexive and adaptive responses to perturbation of fo were not related, nor were their responses related to either measure of auditory acuity to fo. Conclusion: These findings indicate that there may be disparate feedback and feedforward control mechanisms for articulatory and vocal error correction based on auditory feedback. [ABSTRACT FROM AUTHOR]

Purpose: Given the role of auditory perception in voice production, studies have investigated whether impairments in auditory perception may underlie the noted disruptions in speech in Parkinson’s disease (PD). Studies of loudness perception in PD show impairments in the perception of self-generated speech, but not external tones. Studies of pitch perception in PD have only examined external tones, but these studies differed in terms of the interstimulus intervals (ISIs) that were used, did not examine the impact of cognition, and report conflicting results. To clarify pitch perception in PD, this work investigated perception of self-generated vocal pitch, controlling for cognition and ISI. Method: A total of 30 individuals with and without PD completed (a) hearing threshold testing, (b) the Montreal Cognitive Assessment, and (c) an adaptive just-noticeable-difference paradigm under two separate ISIs (100 ms and 1,000 ms) to assess acuity to self-generated vocal pitch. Results: There was no significant difference in acuity between individuals with and without PD. Both groups demonstrated significantly worse acuity for longer compared to shorter ISIs. Montreal Cognitive Assessment scores were not a significant predictor of acuity. Conclusions: The results suggest that acuity to self-generated vocal pitch does not differ between individuals with and without PD. [ABSTRACT FROM AUTHOR]

Purpose: Gradual and sudden perturbations of vocal fundamental frequency (fo), also known as adaptive and reflexive fo perturbations, are techniques to study the influence of auditory feedback on voice fo control mechanisms. Previous vocal fo perturbations have incorporated varied setup-specific feedback delays and amplifications. Here, we investigated the effects of feedback delays (10–100 ms) and amplifications on both adaptive and reflexive fo perturbation paradigms, encapsulating the variability in equipment-specific delays (3–45 ms) and amplifications utilized in previous experiments. Method: Responses to adaptive and reflexive fo perturbations were recorded in 24 typical speakers for four delay conditions (10, 40, 70, and 100 ms) or three amplification conditions (−10, +5, and +10 dB relative to microphone) in a counterbalanced order. Repeatedmeasures analyses of variance were carried out on the magnitude of fo responses to determine the effect of feedback condition. Results: There was a statistically significant effect of the level of auditory feedback amplification on the response magnitude during adaptive fo perturbations, driven by the difference between +10- and −10-dB amplification conditions (hold phase difference: M = 38.3 cents, SD = 51.2 cents; after-effect phase: M = 66.1 cents, SD = 84.6 cents). No other statistically significant effects of condition were found for either paradigm. Conclusions: Experimental equipment delays below 100 ms in behavioral paradigms do not affect the results of fo perturbation paradigms. As there is no statistically significant difference between the response magnitudes elicited by +5- and +10-dB auditory amplification conditions, this study is a confirmation that an auditory feedback amplification of +5 dB relative to microphone is sufficient to elicit robust compensatory responses for fo perturbation paradigms. [ABSTRACT FROM AUTHOR]

Sensorimotor adaptation experiments are commonly used to examine motor learning behavior and to uncover information about the underlying control mechanisms of many motor behaviors, including speech production. In the speech and voice domains, aspects of the acoustic signal are shifted/perturbed over time via auditory feedback manipulations. In response, speakers alter their production in the opposite direction of the shift so that their perceived production is closer to what they intended. This process relies on a combination of feedback and feedforward control mechanisms that are difficult to disentangle. The current study describes and tests a simple 3-parameter mathematical model that quantifies the relative contribution of feedback and feedforward control mechanisms to sensorimotor adaptation. The model is a simplified version of the DIVA model, an adaptive neural network model of speech motor control. The three fitting parameters of SimpleDIVA are associated with the three key subsystems involved in speech motor control, namely auditory feedback control, somatosensory feedback control, and feedforward control. The model is tested through computer simulations that identify optimal model fits to six existing sensorimotor adaptation datasets. We show its utility in (1) interpreting the results of adaptation experiments involving the first and second formant frequencies as well as fundamental frequency; (2) assessing the effects of masking noise in adaptation paradigms; (3) fitting more than one perturbation dimension simultaneously; (4) examining sensorimotor adaptation at different timepoints in the production signal; and (5) quantitatively predicting responses in one experiment using parameters derived from another experiment. The model simulations produce excellent fits to real data across different types of perturbations and experimental paradigms (mean correlation between data and model fits across all six studies = 0.95 ± 0.02). The model parameters provide a mechanistic explanation for the behavioral responses to the adaptation paradigm that are not readily available from the behavioral responses alone. Overall, SimpleDIVA offers new insights into speech and voice motor control and has the potential to inform future directions of speech rehabilitation research in disordered populations. Simulation software, including an easy-to-use graphical user interface, is publicly available to facilitate the use of the model in future studies. [ABSTRACT FROM AUTHOR]

Purpose: While orthographic transcription (OT) is the gold standard for measures of intelligibility, it is relatively inaccessible to clinicians. This study investigates the relationship between visual analog scale (VAS) ratings and OT measures of intelligibility for speakers with Parkinson's disease (PD), with the eventual goal of developing more clinically feasible assessments of intelligibility. Method: Twenty speakers with PD and 5 controls read 11 sentences. First, 33 listeners completed an OT task using 1 sentence from each speaker. An additional 33 listeners rated the intelligibility of 1 sentence from each speaker using a VAS, reflecting a minimized exposure VAS (MEV) task. Lastly, 14 additional listeners each rated the intelligibility of all 11 sentences produced by all speakers using a VAS, reflecting an extended exposure VAS (EEV) task. Smaller listener groups were simulated from each VAS task for comparison to scores from the OT task. Results: There was a strong relationship between OT and both MEV and EEV. This relationship remained strong (R2 ≥ .82) even when only 1 listener in MEV and 2 listeners in EEV were simulated per sentence. Conclusions: VAS ratings may be a suitable alternative to OT measures of sentence intelligibility for PD using listeners with both minimal and extended exposure to the stimuli. [ABSTRACT FROM AUTHOR]

Bone conduction (BC) is heavily relied upon in the diagnosis and treatment of hearing loss, but is poorly understood. For example, the relative importance and frequency dependence of various identified BC sound transmission mechanisms that contribute to activate the cochlear partition remain unknown. Recently, we have developed techniques in fresh human cadaveric specimens to directly measure scalae pressures with micro-fiberoptic sensors, enabling us to monitor the input pressure drive across the cochlear partition that triggers the cochlear traveling wave during air conduction (AC) and round-window stimulation. However, BC stimulation poses challenges that can result in inaccurate intracochlear pressure measurements. Therefore, we have developed a new technique described here that allows for precise measurements during BC. Using this new technique, we found that BC stimulation resulted in pressure in scala vestibuli that was significantly higher in magnitude than in scala tympani for most frequencies, such that the differential pressure across the partition-the input pressure drive-was similar to scala vestibuli pressure. BC (stimulated by a Bone Anchored Hearing Aid [Baha]) showed that the mechanisms of sound transmission in BC differ from AC, and also showed the limitations of the Baha bandwidth. Certain kinematic measurements were generally proportional to the cochlear pressure input drive: for AC, velocity of the stapes, and for BC, low-frequency acceleration and high-frequency velocity of the cochlear promontory. Therefore, our data show that to estimate cochlear input drive in normal ears during AC, stapes velocity is a good measure. During BC, cochlear input drive can be estimated for low frequencies by promontory acceleration (though variable across ears), and for high frequencies by promontory velocity. [ABSTRACT FROM AUTHOR]

Purpose: Reduced intensity is a hallmark of speech production in Parkinson's disease (PD). Previous work has examined the perception of intensity in PD to explain these speech deficits. This study reports loudness ratings of pure tones by individuals with PD and controls, all with normal thesholds for older adults. Method: Twenty individuals with PD and 23 age- and sex-matched controls rated the loudness of pure tones from 1 (very soft) to 7 (uncomfortably loud). Tones at 500, 750, 1000, 2000, and 4000 Hz were presented from 35 to 80 dB HL (or until a rating of 7 was given). A mixed-model analysis of variance was performed on ratings to assess the effects of group, frequency, sound intensity, and ear. Loudness growth slopes were determined for each participant and analyzed by group. Results: The mean loudness growth slopes of the control and PD groups did not significantly differ. Conclusions: No difference was found in loudness growth slopes in response to externally generated tones in PD. This is in contrast with the findings of previous studies of self-generated speech and externally presented speech. The underlying causes for impaired perception and production of loudness in PD require further investigation. [ABSTRACT FROM AUTHOR]

Objective: This study examined adaptive responses to auditory perturbation of fundamental frequency (fo) in speakers with Parkinson’s disease (PD) and control speakers. Method: Sixteen speakers with PD and nineteen control speakers produced sustained vowels while they received perturbed auditory feedback (i.e., fo shifted upward or downward). Speakers’ pitch acuity was quantified using a just-noticeable-difference (JND) paradigm. Twelve listeners provided estimates of the speech intelligibility for speakers with PD. Results: Fifteen responses from each speaker group for each shift direction were included in analyses. While control speakers generally showed consistent adaptive responses opposing the perturbation, speakers with PD showed no compensation on average, with individual PD speakers showing highly variable responses. In the PD group, the degree of compensation was not significantly correlated with age, disease progression, pitch acuity, or intelligibility. Conclusions: These findings indicate reduced adaptation to sustained fo perturbation and higher variability in PD compared to control participants. No significant differences were seen in pitch acuity between groups, suggesting that the fo adaptation deficit in PD is not the result of purely perceptual mechanisms. Significance: These results suggest there is an impairment in vocal motor control in PD. Building on these results, contributions can be made to developing targeted voice treatments for PD. [ABSTRACT FROM AUTHOR]

Purpose: The vocal auditory-motor control of individuals with hyperfunctional voice disorders was examined using a sensorimotor adaptation paradigm. Method: Nine individuals with hyperfunctional voice disorders and 9 individuals with typical voices produced sustained vowels over 160 trials in 2 separate conditions: (a) while experiencing gradual upward perturbations in the fundamental frequency (fo) of their auditory feedback (shift-up) and (b) under no auditory perturbation (control). The shift-up condition consisted of 4 ordered (fixed) phases: baseline (no perturbation), ramp (gradual increases in heard fo), hold (a consistently higher heard fo), and after-effect (no perturbation). Adaptive responses were defined as the difference in produced fo during control and shift-up conditions. Results: Adaptive responses were significantly different between groups. Individuals with typical voices generally showed compensatory adaptive responses, with decreased fo during the ramp and hold phases. Conversely, many individuals with hyperfunctional voice disorders instead displayed the opposite effect by following the direction of the perturbation. When fo was experimentally increased, speakers further increased their fo. Conclusion: Results indicate that some individuals diagnosed with hyperfunctional voice disorders have disrupted auditory-motor control, suggesting atypical neurological function. These findings may eventually allow for the development of new interventions for hyperfunctional voice disorders. [ABSTRACT FROM AUTHOR]