An open-source toolbox for measuring vocal tract shape from real-time magnetic resonance images.

Real-time magnetic resonance imaging (rtMRI) is a technique that provides high-contrast videographic data of human anatomy in motion. Applied to the vocal tract, it is a powerful method for capturing the dynamics of speech and other vocal behaviours by imaging structures internal to the mouth and throat. These images provide a means of studying the physiological basis for speech, singing, expressions of emotion, and swallowing that are otherwise not accessible for external observation. However, taking quantitative measurements from these images is notoriously difficult. We introduce a signal processing pipeline that produces outlines of the vocal tract from the lips to the larynx as a quantification of the dynamic morphology of the vocal tract. Our approach performs simple tissue classification, but constrained to a researcher-specified region of interest. This combination facilitates feature extraction while retaining the domain-specific expertise of a human analyst. We demonstrate that this pipeline generalises well across datasets covering behaviours such as speech, vocal size exaggeration, laughter, and whistling, as well as producing reliable outcomes across analysts, particularly among users with domain-specific expertise. With this article, we make this pipeline available for immediate use by the research community, and further suggest that it may contribute to the continued development of fully automated methods based on deep learning algorithms.

Vocal tract shape variation contributes to individual vocal identity in African penguins.

Variation in formant frequencies has been shown to affect social interactions and sexual competition in a range of avian species. Yet, the anatomical bases of this variation are poorly understood. Here, we investigated the morphological correlates of formants production in the vocal apparatus of African penguins. We modelled the geometry of the supra-syringeal vocal tract of 20 specimens to generate a population of virtual vocal tracts with varying dimensions. We then estimated the acoustic response of these virtual vocal tracts and extracted the centre frequency of the first four predicted formants. We demonstrate that: (i) variation in length and cross-sectional area of vocal tracts strongly affects the formant pattern, (ii) the tracheal region determines most of this variation, and (iii) the skeletal size of penguins does not correlate with the trachea length and consequently has relatively little effect on formants. We conclude that in African penguins, while the variation in vocal tract geometry generates variation in resonant frequencies supporting the discrimination of conspecifics, such variation does not provide information on the emitter's body size. Overall, our findings advance our understanding of the role of formant frequencies in bird vocal communication.

Relationship of cepstral analysis with voice self-assessments in dysphonic and normal speakers.

PURPOSE: This study aimed to investigate the relationship of cepstral analysis (Cepstral Peak Prominence [CPP] and Cepstral Peak Prominence-Smoothed [CPPS]) with voice self-assessments (The Persian version of vocal tract discomfort [VTDp] scale and non-standard hoarseness self-assessment [NHS] questionnaire). METHODS: 223 participants (159 with and 64 without dysphonia) were asked to utter the vocal tasks namely vowels /a/ and /e/, six standard sentences, and a non-standard connected speech sample. CPP and CPPS were calculated in these three vocal tasks using the "Praat" software. The participants also asked to complete the VTDp scale and the NHS questionnaire. RESULTS: The means of frequency and severity the VTDp and the means of NHS were statistically different between the dysphonic and normal voice groups (P < 0.05), except for tickling (P > 0.05). There was a very low significant correlation between cepstral analysis with aching and in the dysphonic group (P < 0.05). However, a very low to low significant correlation between cepstral analysis with burning, tight, aching, tickling, sore, and both frequency and severity subscales scores of the VTDp in the normal voice group (P < 0.05). Moreover, the means of the cepstral analysis did not differ significantly between all scores of the NHS in the dysphonic the normal voice groups (P > 0.05), except for 1 with 3, 4, and 5 in the dysphonic group (P < 0.05). CONCLUSION: The cepstral analysis can provide some information about the status of vocal tract and person's perception of his/her own voice quality.

The comparison between vocal facilitating techniques, manual circumlaryngeal therapy, and combined voice therapy in teachers with muscle tension dysphonia: a randomized clinical trial.

PURPOSE: Although voice therapy (VT) has been known effective in muscle tension dysphonia (MTD), it is not obviously clear which VT approach is more effective. This study aimed to compare the effectiveness of Vocal Facilitating Techniques (VFTs), Manual Circumlaryngeal Therapy (MCT), and combined VT in teachers with MTD. METHODS: This study was a double-blind parallel randomized clinical trial. Thirty elementary female teachers with MTD were divided into three treatment groups including VFTs; MCT, and combined VT. In addition, vocal hygiene was presented to all groups. All participants received 10 individual 45-min sessions of VT twice a week. The effectiveness was assessed using Vocal Tract Discomfort (VTD) scale and Dysphonia Severity Index (DSI) before and after treatment and improvement measurement was calculated. The participants and data analyzer were blinded to the type of VT. RESULTS: All groups showed significantly better results on the subscales of VTD scale and DSI score after VT (p ≤ 0.001; η2 ≥ 0.90). There was a significant difference between the three groups on the results of VTD scale and DSI score (p ≤ 0.05). The improvement measurement on the VTD severity subscale and DSI score following the combined VT was the greatest compared with other groups (η2 = 0.99 and 0.98, respectively). The significant interactive effect of treatment and time was observed on the VTD severity subscale and DSI score (p < 0.05; η2 ≥ 0.56). CONCLUSIONS: This study showed that the VFTs, MCT, and combined VT were effective for MTD teachers, and the combined VT is the most effective one. It seems the combination of different approaches is recommended for the VT of MTD patients.

Immediate effects of straw phonation in air or water on the laryngeal function and configuration of female speech-language pathology students visualised with strobovideolaryngoscopy: A randomised controlled trial.

BACKGROUND: A promising way to obtain vocal economy and efficiency is by semi-occluding the vocal tract while phonating. Current knowledge about the immediate effects of semi-occluded vocal tract (SOVT) phonation on the laryngeal function and configuration is based mainly on computer modelling or excised larynges studies. In in vivo SOVT studies, electroglottography (EGG) has been the most commonly used laryngeal outcome, showing contradictory results between studies. Therefore, exploring these aspects by direct visualisation of the human larynx during SOVT phonation using strobovideolaryngoscopy (SVL) is needed. AIMS: The aim of this study was to investigate and compare the immediate effects of straw phonation (SP) in air, SP in 2 cm water, and SP in 5 cm water (with stirring straws), on the laryngeal function and configuration of a homogeneous group of vocally healthy female speech-language pathology students, visualised with flexible SVL. METHODS & PROCEDURE: A randomised controlled trial was used. Fifty-two female speech-language pathology students (mean age: 18.7 years, SD: 0.6) were assigned randomly to one of three experimental groups or a control group: (1) SP in air, (2) SP in 2 cm water, (3) SP in 5 cm water or (4) [u] phonation with similar soft onset and slightly pursed lips as in SP but without a straw (control group). The participants underwent flexible SVL during habitual [u] phonation, followed by the specific SOVT exercise of their group assignment. All video samples were evaluated randomly and blindly by two experienced investigators using the Voice-Vibratory Assessment with Laryngeal Imaging (VALI) rating form, first independently and then by consensus. OUTCOME & RESULTS: Compared to habitual phonation, the vibrational amplitude decreased during SP in 5 cm water and SP in 2 cm water, being more prominent in the first, more flow-resistant exercise. The mucosal wave also decreased during SP in 5 cm water. The anteroposterior (AP) supraglottic compression similarly increased during SP in air, SP in 2 cm water, and SP in 5 cm water. Further, a rise in mediolateral (ML) compression and a decrease in phase symmetry and regularity were found during SP in 2 cm water. A similar decrease in regularity was observed during SP in 5 cm water. CONCLUSIONS & IMPLICATIONS: Both SP in air and SP in water cause positive immediate laryngeal effects for voice training opportunities. More AP supraglottic activity found during each SP exercise might indicate epilarynx narrowing, an economic phenomenon associated with SOVT. Immersing the straw in water additionally diminished the vibrational amplitude, lowering vocal fold impact stress and risk for phonotrauma during the exercise. The decreased regularity of the vibrational cycles during SP in water might be due to the varying back pressure created by the water bubbling. The impact of SP in water on ML supraglottic compression needs further investigation. WHAT THIS PAPER ADDS: What is already known on the subject A promising way to obtain vocal economy and efficiency is by semi-occluding the vocal tract while phonating. Current knowledge about the immediate effects of semi-occluded vocal tract (SOVT) phonation on the laryngeal function and configuration is based mainly on computer modelling or excised larynges studies. In in vivo SOVT studies, electroglottography (EGG) has been the most commonly used laryngeal outcome, showing contradictory results between studies. Therefore, exploring these aspects by direct visualisation of the human larynx during SOVT phonation using strobovideolaryngoscopy (SVL) is needed. What this paper adds to existing knowledge Group results of the current study generally support earlier computer modelling and in vivo studies, strengthening the current SOVT knowledge. Both SP in air and SP in water cause positive immediate laryngeal effects for voice training opportunities. More anteroposterior (AP) supraglottic activity found during each SP exercise might indicate epilarynx narrowing, an economic phenomenon associated with SOVT. Immersing the straw in water additionally diminished the vibrational amplitude, lowering vocal fold impact stress and risk for phonotrauma during the exercise. The decreased regularity of the vibrational cycles during SP in water might be due to the varying back pressure created by the water bubbling. The impact of SP in water on ML supraglottic compression needs further investigation. What are the potential or actual clinical implications of this work? Current results support that both SP in air and SP in water can be useful exercises in voice training. SP in water has shown the additional gain of lowering the vibrational amplitude during the exercise, hence supporting its appropriateness for vocal warm-ups by minimising vocal fold impact stress and the risk of phonotrauma. In the future, large-scale randomised controlled trials in other subgroups of voice users, including dysphonic patients, are needed to support evidence-based practice. SVL can facilitate the search for individualised training and therapy approaches.

Vocal Tract Resonance Detection at Low Frequencies: Improving Physical and Transducer Configurations.

Broadband excitation introduced at the speaker's lips and the evaluation of its corresponding relative acoustic impedance spectrum allow for fast, accurate and non-invasive estimations of vocal tract resonances during speech and singing. However, due to radiation impedance interactions at the lips at low frequencies, it is challenging to make reliable measurements of resonances lower than 500 Hz due to poor signal to noise ratios, limiting investigations of the first vocal tract resonance using such a method. In this paper, various physical configurations which may optimize the acoustic coupling between transducers and the vocal tract are investigated and the practical arrangement which yields the optimal vocal tract resonance detection sensitivity at low frequencies is identified. To support the investigation, two quantitative analysis methods are proposed to facilitate comparison of the sensitivity and quality of resonances identified. Accordingly, the optimal configuration identified has better acoustic coupling and low-frequency response compared with existing arrangements and is shown to reliably detect resonances down to 350 Hz (and possibly lower), thereby allowing the first resonance of a wide range of vowel articulations to be estimated with confidence.

Method for Fabricating Transparent Patient-Specific Vocal Tract Replicas.

INTRODUCTION: Transparent, patient-specific vocal tract replicas are helpful in research and educational endeavors but challenging to procure. An accessible method for fabricating these models, improving on previously suggested processes, would make them more widely available. METHOD: Detailed instructions for fabricating a transparent, patient-specific vocal tract model were addressed. The broad steps were (1) digitally reconstructing (patient-specific) vocal tract geometry, (2) producing a vocal tract mold (using methods such as three-dimensional [3D] printing), and (3) casting transparent material (such as silicone) around the vocal tract mold and removing the mold. The cavities remaining within the cast represented the exact geometry of the vocal tract. DISCUSSION: A combination of 3D printing and silicone casting can produce useful vocal tract replicas. Several simple changes to previous methods can improve consistency and reduce the labor and cost of production. Limitations and potential modifications to expand the applications of this method are discussed.

A practical guide to calculating vocal tract length and scale-invariant formant patterns.

Formants (vocal tract resonances) are increasingly analyzed not only by phoneticians in speech but also by behavioral scientists studying diverse phenomena such as acoustic size exaggeration and articulatory abilities of non-human animals. This often involves estimating vocal tract length acoustically and producing scale-invariant representations of formant patterns. We present a theoretical framework and practical tools for carrying out this work, including open-source software solutions included in R packages soundgen and phonTools. Automatic formant measurement with linear predictive coding is error-prone, but formant_app provides an integrated environment for formant annotation and correction with visual and auditory feedback. Once measured, formants can be normalized using a single recording (intrinsic methods) or multiple recordings from the same individual (extrinsic methods). Intrinsic speaker normalization can be as simple as taking formant ratios and calculating the geometric mean as a measure of overall scale. The regression method implemented in the function estimateVTL calculates the apparent vocal tract length assuming a single-tube model, while its residuals provide a scale-invariant vowel space based on how far each formant deviates from equal spacing (the schwa function). Extrinsic speaker normalization provides more accurate estimates of speaker- and vowel-specific scale factors by pooling information across recordings with simple averaging or mixed models, which we illustrate with example datasets and R code. The take-home messages are to record several calls or vowels per individual, measure at least three or four formants, check formant measurements manually, treat uncertain values as missing, and use the statistical tools best suited to each modeling context.

Tonality over a broad frequency range is linked to vocal learning in birds.

Many birds emit tonal song syllables even though the sound sources generate sound with rich upper harmonic energy content. This tonality is thought to arise in part from dynamically adjusted filtering of harmonic content. Here, we compare tonality of song syllables between vocal learners and non-learners to assess whether this characteristic is linked to the increased neural substrate that evolved with vocal learning. We hypothesize that vocal learning ability is correlated with enhanced ability for generating tonal sounds, because vocal production learners might also have an enhanced ability to articulate their vocal tracts and sound source for producing tonality. To test this hypothesis, we compared vocal learners and non-learners from two groups (186 passerines and 42 hummingbirds) by assessing tonality of song syllables. The data suggest that vocal learners in both clades have evolved to sing songs with higher tonality than the related, non-vocal learning clades, which is consistent with stronger roles for broadband dynamic filtering and adjustments to the sound source. In addition, oscine songs display higher tonality than those of hummingbirds. A complex interplay of vocal tract biomechanics, anatomical differences of the sound source as well as increased motor control through vocal learning facilitates generation of broad tonality.

Vocal tract allometry in a mammalian vocal learner.

Acoustic allometry occurs when features of animal vocalisations can be predicted from body size measurements. Despite this being considered the norm, allometry sometimes breaks, resulting in species sounding smaller or larger than expected for their size. A recent hypothesis suggests that allometry-breaking mammals cluster into two groups: those with anatomical adaptations to their vocal tracts and those capable of learning new sounds (vocal learners). Here, we tested which mechanism is used to escape from acoustic allometry by probing vocal tract allometry in a proven mammalian vocal learner, the harbour seal (Phoca vitulina). We tested whether vocal tract structures and body size scale allometrically in 68 young individuals. We found that both body length and body mass accurately predict vocal tract length and one tracheal dimension. Independently, body length predicts vocal fold length while body mass predicts a second tracheal dimension. All vocal tract measures are larger in weaners than in pups and some structures are sexually dimorphic within age classes. We conclude that harbour seals do comply with anatomical allometric constraints. However, allometry between body size and vocal fold length seems to emerge after puppyhood, suggesting that ontogeny may modulate the anatomy-learning distinction previously hypothesised as clear cut. We suggest that seals, and perhaps other species producing signals that deviate from those expected from their vocal tract dimensions, may break allometry without morphological adaptations. In seals, and potentially other vocal learning mammals, advanced neural control over vocal organs may be the main mechanism for breaking acoustic allometry.

Domestic dogs (Canis lupus familiaris) are sensitive to the correlation between pitch and timbre in human speech.

The perceived pitch of human voices is highly correlated with the fundamental frequency (f0) of the laryngeal source, which is determined largely by the length and mass of the vocal folds. The vocal folds are larger in adult males than in adult females, and men's voices consequently have a lower pitch than women's. The length of the supralaryngeal vocal tract (vocal-tract length; VTL) affects the resonant frequencies (formants) of speech which characterize the timbre of the voice. Men's longer vocal tracts produce lower frequency, and less dispersed, formants than women's shorter vocal tracts. Pitch and timbre combine to influence the perception of speaker characteristics such as size and age. Together, they can be used to categorize speaker sex with almost perfect accuracy. While it is known that domestic dogs can match a voice to a person of the same sex, there has been no investigation into whether dogs are sensitive to the correlation between pitch and timbre. We recorded a female voice giving three commands ('Sit', 'Lay down', 'Come here'), and manipulated the recordings to lower the fundamental frequency (thus lowering pitch), increase simulated VTL (hence affecting timbre), or both (synthesized adult male voice). Dogs responded to the original adult female and synthesized adult male voices equivalently. Their tendency to obey the commands was, however, reduced when either pitch or timbre was manipulated alone. These results suggest that dogs are sensitive to both the pitch and timbre of human voices, and that they learn about the natural covariation of these perceptual attributes.

Prevalence of vocal tract discomfort in patients with voice disorders.

OBJECTIVE: To analyse the prevalence of vocal tract discomfort in patients with voice disorders. METHODS: The analytical cross-sectional study was conducted at Riphah International University, Lahore, Pakistan, from September 2020 to January 2021, and comprised voice disorder patients of either gender aged 18-65 years enrolled from Mayo Hospital, Sheikh Zayed Hospital and Jinnah Hospital, Lahore. The Vocal Tract Discomfort Scale was used for data-collection. Data was analysed using SPSS 21. RESULTS: Of the 137 patients, 68(49.6%) were males and 69(50.4%) were females. The overall mean age was 36.36±12.47 years. The most affected age group was 18-33 years 70(51.1%) while those aged 50-65 years were the least affected 28(20.4%). The most common VTD symptom was dryness with mean frequency 3.48±1.97 and mean severity 3.36±1.99, followed by irritation 2.88±2.08 and 2.88±2.12, and lump in the throat 2.42±2.27 and 2.31±2.23, respectively. CONCLUSIONS: Dryness, irritation and a lump in the throat were the most common symptoms of vocal tract discomfort.

Comparison of auto-contouring and hand-contouring of ultrasound images of the tongue surface.

Contours traced by trained phoneticians have been considered to be the most accurate way to identify the midsagittal tongue surface from ultrasound video frames. In this study, inter-measurer reliability was evaluated using measures that quantified both how closely human-placed contours approximated each other as well as how consistent measurers were in defining the start and end points of contours. High reliability across three measurers was found for all measures, consistent with treating contours placed by trained phoneticians as the 'gold standard.' However, due to the labour-intensive nature of hand-placing contours, automatic algorithms that detect the tongue surface are increasingly being used to extract tongue-surface data from ultrasound videos. Contours placed by six automatic algorithms (SLURP, EdgeTrak, EPCS, and three different configurations of the algorithm provided in Articulate Assistant Advanced) were compared to human-placed contours, with the same measures used to evaluate the consistency of the trained phoneticians. We found that contours defined by SLURP, EdgeTrak, and two of the AAA configurations closely matched the hand-placed contours along sections of the image where the algorithms and humans agreed that there was a discernible contour. All of the algorithms were much less reliable than humans in determining the anterior (tongue-tip) edge of tongue contours. Overall, the contours produced by SLURP, EdgeTrak, and AAA should be useable in a variety of clinical applications, subject to spot-checking. Additional practical considerations of these algorithms are also discussed.

Comparison of vocal fatigue and vocal tract discomfort between teachers of normal pupils and teachers of mentally disabled pupils.

PURPOSE: This study aims to study the comparison of vocal fatigue and vocal tract discomfort between teachers of normal pupils and teachers of mentally disabled pupils. STUDY DESIGN: Cross-sectional study METHODS: Participants were 179 teachers (50 male, 129 female) and 30 non-teachers (14 male, 16 female) who participated in the current study. The teachers work in elementary schools. Furthermore, 87 of the teachers work for mentally disabled pupils at special elementary schools. Non-teachers were Ahvaz Jundishapur University of Medical Sciences employees who consider as the control group. They completed the Persian VFI and VTDp questionnaires three times, at the beginning, middle, and end of their office hours for 1 workday. RESULTS: The current study's findings indicate that the Persian VFI and VTD scores of non-teachers were significantly lower than teachers' scores. Furthermore, teachers of mentally disabled pupils demonstrated higher values from teachers of normal pupils based on the Persian VFI and VTDp scores CONCLUSION: The study results showed that teachers experienced more vocal fatigue and vocal tract discomfort than non-teachers. Furthermore, teachers of mentally disabled pupils indicated more vocal fatigue, the larynx's physical discomfort, and vocal tract discomfort, but this difference was practically small.

Savannah roars: The vocal anatomy and the impressive rutting calls of male impala (Aepyceros melampus) - highlighting the acoustic correlates of a mobile larynx.

A retractable larynx and adaptations of the vocal folds in the males of several polygynous ruminants serve for the production of rutting calls that acoustically announce larger than actual body size to both rival males and potential female mates. Here, such features of the vocal tract and of the sound source are documented in another species. We investigated the vocal anatomy and laryngeal mobility including its acoustical effects during the rutting vocal display of free-ranging male impala (Aepyceros melampus melampus) in Namibia. Male impala produced bouts of rutting calls (consisting of oral roars and interspersed explosive nasal snorts) in a low-stretch posture while guarding a rutting territory or harem. For the duration of the roars, male impala retracted the larynx from its high resting position to a low mid-neck position involving an extensible pharynx and a resilient connection between the hyoid apparatus and the larynx. Maximal larynx retraction was 108 mm based on estimates in video single frames. This was in good concordance with 91-mm vocal tract elongation calculated on the basis of differences in formant dispersion between roar portions produced with the larynx still ascended and those produced with maximally retracted larynx. Judged by their morphological traits, the larynx-retracting muscles of male impala are homologous to those of other larynx-retracting ruminants. In contrast, the large and massive vocal keels are evolutionary novelties arising by fusion and linear arrangement of the arytenoid cartilage and the canonical vocal fold. These bulky and histologically complex vocal keels produced a low fundamental frequency of 50 Hz. Impala is another ruminant species in which the males are capable of larynx retraction. In addition, male impala vocal folds are spectacularly specialized compared with domestic bovids, allowing the production of impressive, low-frequency roaring vocalizations as a significant part of their rutting behaviour. Our study expands knowledge on the evolutionary variation of vocal fold morphology in mammals, suggesting that the structure of the mammalian sound source is not always human-like and should be considered in acoustic analysis and modelling.

[Pretesting of the German Vocal Fatigue Index (VFI-D)-transcultural translation and cross validation]. / Prätestung des deutschen Vocal Fatigue Index (VFI-D) ­ transkulturelle Übersetzung und Kreuzvalidierung.

BACKGROUND: In clinical routine, vocal fatigue is a common symptom in patients with dysphonia. OBJECTIVE: The aim of this study was to conduct a transcultural translation of the Vocal Fatigue Index (VFI), a standardized subjective questionnaire. Furthermore, pretesting and prevalidation were performed in 20 subjects, with comparison to the Voice Handicap Index (VHI­9i) and the Vocal Tract Discomfort Scale (VTD). MATERIALS AND METHODS: The translation, content review, and pretest of the German Vocal Fatigue Index (VFI-D) was divided into four sections: 1. transcultural translation, 2. expert voting on comprehensibility, 3. test of comprehensibility through cognitive interviews in 15 participants, 4. pretest of the VFI­D with cross validation compared to VHI­9i and VTD in 20 subjects. This process corresponds to current standards for transcultural translation and adaptation of questionnaires. RESULTS: According to expert voting and cognitive testing, the VFI­D is correct and comprehensible (intercoder reliability κ = 0.66). The factor analysis revealed three distinguishable parts: VFI­D part 1 correlates strongly with VHI­9i and VTD, VFI­D part 2 with VTD only (rho ≈ 0.800 each), and VFI­D part 3 correlates only weakly with VHI­9i and VTD (rho ≈ 0.585). Thus, convergence and divergence validity are proven. CONCLUSION: The first German version of the VFI­D might be a base for further research on symptoms, causes, and treatment options in vocal fatigue. Particularly patients in voice-intensive professions may benefit.

Water Resistance Therapy as Vocal Warm-Up Method in Contemporary Commercial Music Singers.

BACKGROUND/AIMS: Although water resistance therapy (WRT) has been widely used in voice training, no data are supporting the effectiveness of WRT as vocal warm-up for singers. The present study aimed to determine the effects of WRT as a vocal warm-up method in contemporary commercial music (CCM) singers. METHODS: Twenty-two CCM singers were randomly assigned to one of two types of 15-min vocal warm-up: open vocal tract (OVT) warm-up and WRT. Self-perceived resonant voice quality and aerodynamic, electroglottographic, and acoustic measures were assessed before, immediately after vocal warm-up, and after 40 min of vocal loading. RESULTS: Significant results were found immediately after vocal warm-up. Subglottic pressure and inspiratory airflow duration decreased in both groups. SPL decreased for the OVT group. No changes in SPL were found for the WRT group. Significant results were observed after vocal loading. Subglottic pressure and inspiratory airflow duration decreased for both groups after vocal loading. Expiratory airflow duration and electroglottographic contact quotient decreased for the OVT group. CONCLUSION: Some objective data suggest that the WRT method is more effective as vocal warm-up than OVT exercises. Since outcomes in self-perceived resonant voice quality for both methods were similar but physiological effects were different, vocal warm-up strategies might produce a placebo effect.

The influence of the vocal tract on the attack transients in clarinet playing.

When playing single-reed woodwind instruments, players can modulate the spectral content of the airflow in their vocal tract, upstream of the vibrating reed. In an empirical study with professional clarinettists ( N p = 11 ), blowing pressure and mouthpiece pressure were measured during the performance of Clarinet Concerto excerpts. By comparing mouth pressure and mouthpiece pressure signals in the time domain, a method to detect instances of vocal tract adjustments was established. Results showed that players tuned their vocal tract in both clarion and altissimo registers. Furthermore, the analysis revealed that vocal tract adjustments support shorter attack transients and help to avoid lower bore resonances.

3D dynamic MRI of the vocal tract during natural speech.

PURPOSE: To develop and evaluate a technique for 3D dynamic MRI of the full vocal tract at high temporal resolution during natural speech. METHODS: We demonstrate 2.4 × 2.4 × 5.8 mm3 spatial resolution, 61-ms temporal resolution, and a 200 × 200 × 70 mm3 FOV. The proposed method uses 3D gradient-echo imaging with a custom upper-airway coil, a minimum-phase slab excitation, stack-of-spirals readout, pseudo golden-angle view order in kx -ky , linear Cartesian order along kz , and spatiotemporal finite difference constrained reconstruction, with 13-fold acceleration. This technique is evaluated using in vivo vocal tract airway data from 2 healthy subjects acquired at 1.5T scanner, 1 with synchronized audio, with 2 tasks during production of natural speech, and via comparison with interleaved multislice 2D dynamic MRI. RESULTS: This technique captured known dynamics of vocal tract articulators during natural speech tasks including tongue gestures during the production of consonants "s" and "l" and of consonant-vowel syllables, and was additionally consistent with 2D dynamic MRI. Coordination of lingual (tongue) movements for consonants is demonstrated via volume-of-interest analysis. Vocal tract area function dynamics revealed critical lingual constriction events along the length of the vocal tract for consonants and vowels. CONCLUSION: We demonstrate feasibility of 3D dynamic MRI of the full vocal tract, with spatiotemporal resolution adequate to visualize lingual movements for consonants and vocal tact shaping during natural productions of consonant-vowel syllables, without requiring multiple repetitions.

Effects of a simulated system of straw phonation on the complete phonatory range of excised canine larynges.

PURPOSE: This study investigated the effects of straw phonation therapy on the aerodynamic and acoustic parameters of the vocal folds at different levels of elongation and subglottal pressure. METHODS: 20 excised canine larynges were used in both experimental (straw phonation therapy simulation) and control conditions. Aerodynamic parameters, including phonation threshold pressure (PTP), phonation instability pressure (PIP), phonation pressure range (PPR), phonation threshold flow (PTF), phonation instability flow (PIF), phonation flow range (PFR), were obtained at different levels of vocal fold elongation (0%, 10%, 20%). Acoustic parameters, including fundamental frequency (F0), jitter, shimmer, signal noise ratio (SNR) were detected at different levels of vocal fold elongation (0%, 10%, 20%) and subglottal pressure (15 cmH2O, 20 cmH2O, 25 cmH2O). RESULTS: Significant decreases in PTP and PTF and significant increases in PIP, PIF, PPR, and PFR occurred in experimental condition at all levels of elongation when compared with control condition. However, no significant changes of acoustic parameters were obtained between conditions at all levels. CONCLUSION: At different levels of vocal fold elongation, straw phonation not only lowered the onset of normal voice, but also elevated the onset of chaotic voice, indicating a better voice economy and voice control. Moreover, the improved phonatory range demonstrated that straw phonation had the potential to prevent voice users who have high voice demand from voice fatigue and vocal damage.