scholarly journals Acoustic and Aerodynamic Coupling during Phonation in MRI-Based Vocal Tract Replicas

2019 ◽  
Vol 9 (17) ◽  
pp. 3562
Author(s):  
Judith Probst ◽  
Alexander Lodermeyer ◽  
Sahar Fattoum ◽  
Stefan Becker ◽  
Matthias Echternach ◽  
...  
Keyword(s):  
Cross Sections ◽  
Vocal Tract ◽  
Vocal Folds ◽  
Aerodynamic Characteristics ◽  
Fluid Structure ◽  
Acoustic Interaction ◽  
Voiced Speech ◽  
3D Printed ◽  
The Mean

Voiced speech is the result of a fluid-structure-acoustic interaction in larynx and vocal tract (VT). Previous studies show a strong influence of the VT on this interaction process, but are limited to individually obtained VT geometries. In order to overcome this restriction and to provide a more general VT replica, we computed a simplified, averaged VT geometry for the vowel /a/. The basis for that were MRI-derived cross-sections along the straightened VT centerline of six professional tenors. The resulting mean VT replica, as well as realistic and simplified VT replicas of each tenor were 3D-printed for experiments with silicone vocal folds that show flow-induced oscillations. Our results reveal that all replicas, including the mean VT, reproduce the characteristic formants with mean deviations of 12% when compared with the subjects’ audio recordings. The overall formant structure neither is impaired by the averaging process, nor by the simplified geometry. Nonetheless, alterations in the broadband, non-harmonic portions of the sound spectrum indicate changed aerodynamic characteristics within the simplified VT. In conclusion, our mean VT replica shows similar formant properties as found in vivo. This indicates that the mean VT geometry is suitable for further investigations of the fluid-structure-acoustic interaction during phonation.

Nonlinear Vocal Fold Dynamics in a Two-Mass Model of Speech Arising From Asymmetric Intraglottal Flow

2011 ◽  
Author(s):  
Byron D. Erath ◽  
Matías Zañartu ◽  
Sean D. Peterson ◽  
Michael W. Plesniak
Keyword(s):  
Vocal Fold ◽  
Vocal Tract ◽  
Vocal Folds ◽  
Attractive Alternative ◽  
Nonlinear Phenomena ◽  
Mass Model ◽  
Sustained Oscillations ◽  
Voiced Speech ◽  
Subglottal Pressure ◽  
Vocal Fold Dynamics

Voiced speech is initiated as air is expelled from the lungs and passes through the vocal tract inciting self-sustained oscillations of the vocal folds. While various approaches exist for investigating both normal and pathological speech, the relative inaccessibility of the vocal folds make multi-mass speech models an attractive alternative. Their behavior has been benchmarked with excised larynx experiments, and they have been used as analysis tools for both normal and disordered speech, including investigations of paralysis, vocal tremor, and breathiness. However, during pathological speech, vocal fold motion is often unstructured, resulting in chaotic motion and a wealth of nonlinear phenomena. Unfortunately, current methodologies for multi-mass speech models are unable to replicate the nonlinear vocal fold behavior that often occurs in physiological diseased voice for realistic values of subglottal pressure.

scholarly journals Accuracy evaluation of a 3D-printed individual template for needle guidance in head and neck brachytherapy

2016 ◽  
Vol 57 (6) ◽  
pp. 662-667 ◽  
Author(s):  
Ming-Wei Huang ◽  
Jian-Guo Zhang ◽  
Lei Zheng ◽  
Shu-Ming Liu ◽  
Guang-Yan Yu
Keyword(s):  
Head And Neck ◽  
Needle Insertion ◽  
Accuracy Evaluation ◽  
Angular Deviation ◽  
3D Printed ◽  
Radioactive Seeds ◽  
The Mean ◽  
125I Radioactive Seeds ◽  
Time Required

Abstract To transfer the preplan for the head and neck brachytherapy to the clinical implantation procedure, a preplan-based 3D-printed individual template for needle insertion guidance had previously been designed and used. The accuracy of needle insertion using this kind template was assessed in vivo. In the study, 25 patients with head and neck tumors were implanted with 125I radioactive seeds under the guidance of the 3D-printed individual template. Patients were divided into four groups based on the site of needle insertion: the parotid and masseter region group (nine patients); the maxillary and paranasal region group (eight patients); the submandibular and upper neck area group (five patients); and the retromandibular region group (six patients). The distance and angular deviations between the preplanned and placed needles were compared, and the complications and time required for needle insertion were assessed. The mean entrance point distance deviation for all 619 needles was 1.18 ± 0.81 mm, varying from 0.857 ± 0.545 to 1.930 ± 0.843 mm at different sites. The mean angular deviation was 2.08 ± 1.07 degrees, varying from 1.85 ± 0.93 to 2.73 ± 1.18 degrees at different sites. All needles were manually inserted to their preplanned positions in a single attempt, and the mean time to insert one needle was 7.5 s. No anatomical complications related to inaccurately placed implants were observed. Using the 3D-printed individual template for the implantation of 125I radioactive seeds in the head and neck region can accurately transfer a CT-based preplan to the brachytherapy needle insertion procedure. Moreover, the addition of individual template guidance can reduce the time required for implantation and minimize the damage to normal tissues.

scholarly journals Positioning accuracy assessment of minimally invasive percutaneous injection techniques for the treatment of temporomandibular disorders

2020 ◽  
pp. 20200313
Author(s):  
Antônio Luís Neto Custódio ◽  
Andrew Cameron ◽  
Mahmoud Bakr ◽  
Chris Little ◽  
Bruno Ramos Chrcanovic ◽  
...  
Keyword(s):  
Accuracy Assessment ◽  
Mean Difference ◽  
Virtual Planning ◽  
Percutaneous Injection ◽  
Mean Values ◽  
Surgical Guide ◽  
Injection Techniques ◽  
3D Printed ◽  
The Mean

Objective: The aim of the present study was to evaluate the accuracy of an extraoral CBCT-planned 3D-printed surgical guide aimed to percutaneous injection of substances into the temporomandibular joint (TMJ) and the lateral pterygoid muscle (LPM). Methods: Nine human cadaver heads were used. Pre-planning CBCT and facial scans were obtained and three percutaneous injection sites were planned: one for the lower compartment of the TMJ and two for the LPM. A digital surgical guide was then designed with small titanium sleeves and printed by a 3D printer. After the injections, new CBCT scans with the needles in place were obtained in order to assess the accuracy of the procedure in relation to the virtual planning. Results: The mean values for angle deviation were very low (range 1.13o-4.08o), the same happening for the mean difference in the length reached (range 1.82–2.64 mm), as well as for the mean difference in the needle tip dislocation (range 0.94–2.03 mm). Conclusion: The guide seems to be a reliable tool for accurate percutaneous injection of drugs into the inferior compartment of the TMJ and the LPM. Further studies are necessary to test the efficacy and validate the method in an in vivo study.

Finite Element Modelling of the Effect of Stiffness and Damping of Vocal Fold Layers on their Vibrations and Produced Sound

2016 ◽  
Vol 821 ◽  
pp. 657-664 ◽  
Author(s):  
Petr Hájek ◽  
Pavel Švancara ◽  
Jaromír Horáček ◽  
Jan G. Švec
Keyword(s):  
Finite Element ◽  
Lamina Propria ◽  
Vocal Tract ◽  
Stokes Equations ◽  
Vocal Folds ◽  
Sustained Oscillation ◽  
Fe Model ◽  
Fluid Structure ◽  
Stiffness And Damping ◽  
Amplitude Decrease

The study presents a two-dimensional (2D) finite element (FE) model of the fluid-structure-acoustic interaction during self-sustained oscillation of the human vocal folds (VF). The FE model combines the FE models of the VF, trachea and a simplified human vocal tract shaped for phonation of a Czech vowel [a:]. The developed FE model comprises large deformations of the VF tissue, VF contact, fluid-structure interaction (FSI), morphing of the fluid mesh according to the VF motion (Arbitrary Lagrangian-Eulerian approach), solution of unsteady viscous compressible airflow described by the Navier-Stokes equations and airflow separation during the glottis closure. The effect of stiffness and damping of lamina propria, which can be caused by certain VF pathologies, on VF vibrations and produced sound are analyzed. The numerical simulations showed that stiffer lamina propria results in a decrease of the maximum width of glottal opening and in a decrease of the fundamental vibration frequency. Stiffer lamina propria also leads to an increase of maximum of the subglottal pressure and it causes amplitude decrease and flattening of the first and second formant in the spectrum of acoustic pressures. Higher values of lamina propria damping result in the amplitude decrease and flattening of all formants.

High-Speed Imaging of Vocal Fold Vibrations and Larynx Movements within Vocalizations of Different Vowels

1996 ◽  
Vol 105 (12) ◽  
pp. 975-981 ◽  
Author(s):  
Dieter Maurer ◽  
Markus Hess ◽  
Manfred Gross
Keyword(s):  
Fundamental Frequency ◽  
Digital Imaging ◽  
Vocal Fold ◽  
High Speed ◽  
Vocal Tract ◽  
Vocal Folds ◽  
High Speed Imaging ◽  
Filter Model ◽  
Acoustic Interaction ◽  
Glottal Source

Theoretic investigations of the “source-filter” model have indicated a pronounced acoustic interaction of glottal source and vocal tract. Empirical investigations of formant pattern variations apart from changes in vowel identity have demonstrated a direct relationship between the fundamental frequency and the patterns. As a consequence of both findings, independence of phonation and articulation may be limited in the speech process. Within the present study, possible interdependence of phonation and phoneme was investigated: vocal fold vibrations and larynx position for vocalizations of different vowels in a healthy man and woman were examined by high-speed light-intensified digital imaging. We found 1) different movements of the vocal folds for vocalizations of different vowel identities within one speaker and at similar fundamental frequency, and 2) constant larynx position within vocalization of one vowel identity, but different positions for vocalizations of different vowel identities. A possible relationship between the vocal fold vibrations and the phoneme is discussed.

Aerodynamic characteristics of trains on a viaduct with non-uniform cross-section under crosswinds by wind tunnel tests

2021 ◽  
pp. 136943322098609
Author(s):  
Kehui Yu ◽  
Xuhui He ◽  
Chenzhi Cai ◽  
Lei Yan ◽  
Yunfeng Zou
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Cross Section ◽  
Cross Sections ◽  
Aerodynamic Characteristics ◽  
Fluctuating Pressure ◽  
Pressure Coefficients ◽  
Mean Wind Speed ◽  
Bridge Girder ◽  
The Mean

This paper focuses on the aerodynamic characteristics of trains on a non-uniform double-track railway bridge under crosswinds through a scaled 1:40 sectional model wind tunnel test. Pressure measurements of five cross-sections of two types of trains, one with round roof and one with blunt roof, at the upstream and downstream tracks of the bridge were conducted under crosswinds with wind attack angles between −12° and 12°. The mean wind speed and turbulence intensity profiles around the windward surface of the train in the downwind and upward directions were also measured using cobra probe to obtain the boundary layer above the bridge surface. The results show that the shapes of train and bridge, as well as the wind attack angle, affect the aerodynamic characteristic of the train on the non-uniform bridge girder. The mean and fluctuating pressure coefficients are similar for all five cross-sections of the trains while the train is at the upstream track. However, when the train is at the downstream track, the extreme mean and fluctuating pressure coefficients around the windward and top surfaces of each cross-section on the train are different. At the downstream track, the mean wind speed profile and the turbulence intensity profile around the top of the train vary dramatically due to the separation flow caused by the leading edge of the bridge girder.

A Wave Reflection Analog Extension for Reduced Order Vocal Fold Investigations With Asymmetric Intraglottal Flows

2012 ◽  
Author(s):  
Byron D. Erath ◽  
Sean D. Peterson ◽  
Matias Zañartu ◽  
Michael W. Plesniak
Keyword(s):  
Vocal Fold ◽  
Vocal Tract ◽  
Coupling Effect ◽  
Vocal Folds ◽  
Tissue Properties ◽  
Sustained Oscillations ◽  
Voiced Speech ◽  
Vocal Fold Dynamics ◽  
Static Fluid ◽  
Speech Science

Voiced speech involves complex fluid-structure-acoustic interactions. When a critical lung pressure is achieved, the vocal folds are pushed apart inciting self-sustained oscillations. The interplay between the aerodynamic forces and the myoelastic tissue properties produces robust oscillation of the vocal folds. The pulsatile nature of the flow as it emanates from vocal folds creates an oscillatory pressure field which acoustically excites the vocal tract and ultimately forms intelligible sound. Recently, it has been shown that the acoustic pressures are high enough in magnitude that they modulate the static fluid pressures which drive the flow.1 This coupling effect creates a feedback loop with the fluids, acoustics, and vocal fold dynamics becoming interconnected. Consequently, speech science investigations that aim to capture the relevant physics must consider all three components to yield credible, clinically-relevant results.

Measurement of Vocal Fold Collision Forces During Phonation

2005 ◽  
Vol 48 (3) ◽  
pp. 567-576 ◽  
Author(s):  
Heather E. Gunter ◽  
Robert D. Howe ◽  
Steven M. Zeitels ◽  
James B. Kobler ◽  
Robert E. Hillman
Keyword(s):  
Vocal Fold ◽  
Vocal Tract ◽  
Tissue Injury ◽  
Vocal Folds ◽  
Force Sensor ◽  
Vocal Fold Vibration ◽  
Low Profile ◽  
Order Of Magnitude ◽  
Collision Force

Forces applied to vocal fold tissue as the vocal folds collide may cause tissue injury that manifests as benign organic lesions. A novel method for measuring this quantity in humans in vivo uses a low-profile force sensor that extends along the length and depth of the glottis. Sensor design facilitates its placement and stabilization so that phonation can be initiated and maintained while it is in place, with minimal interference in vocal fold vibration. In 2 individuals with 1 vibrating vocal fold and 1 nonvibrating vocal fold, peak collision force correlates more strongly with voice intensity than pitch. Vocal fold collision forces in 1 individual with 2 vibrating vocal folds are of the same order of magnitude as in previous studies. Correlations among peak collision force, voice intensity, and pitch were indeterminate in this participant because of the small number of data points. Sensor modifications are proposed so that it can be used to reliably estimate collision force in individuals with 2 vibrating vocal folds and with changing vocal tract conformations.

Magnetic Resonance Imaging of the Vocal Folds in Women With Congenital Adrenal Hyperplasia and Virilized Voices

2016 ◽  
Vol 59 (4) ◽  
pp. 713-721 ◽  
Author(s):  
Ulrika Nygren ◽  
Bengt Isberg ◽  
Stefan Arver ◽  
Stellan Hertegård ◽  
Maria Södersten ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Congenital Adrenal Hyperplasia ◽  
Vocal Tract ◽  
Vocal Folds ◽  
Adrenal Hyperplasia ◽  
Resonance Imaging ◽  
Muscle Area ◽  
Cross Sectional

Purpose Women with congenital adrenal hyperplasia (CAH) may develop a virilized voice due to late diagnosis or suboptimal suppression of adrenal androgens. Changes in the vocal folds due to virilization have not been studied in vivo. The purpose was to investigate if the thyroarytenoid (TA) muscle is affected by virilization and correlate findings to fundamental frequency (F0). Method A case-control study using magnetic resonance imaging and voice recordings. Four women with CAH with virilized voices (26–40 years), and 5 female and 4 male controls participated. Measurements of cross-sectional TA muscle area, vocal fold length, vocal tract length, and acoustic analyses of F0 were performed. Results Women with CAH had larger cross-sectional TA muscle area than female control subjects and smaller than male controls. A significant negative correlation was found between TA muscle area and mean F0. The patients had a smaller physiological voice range than both female and male controls. Conclusion Data from our small study suggest that a larger TA muscle area is strongly associated with a lower F0 and thus the anatomical explanation for a female virilized voice, suggesting an androgen effect on the vocal folds. The findings from the present study need to be confirmed in a larger study.

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