scholarly journals Modelling sagittal and vertical phase differences in a lumped and distributed elements vocal fold model

2021 ◽  
Vol 64 ◽  
pp. 102309
Author(s):  
Carlo Drioli ◽  
Philipp Aichinger
Keyword(s):  
Vocal Fold ◽  
Phase Differences ◽  
Distributed Elements

Comments on the Myoelastic - Aerodynamic Theory of Phonation

1980 ◽  
Vol 23 (3) ◽  
pp. 495-510 ◽  
Author(s):  
Ingo R. Titze
Keyword(s):  
Vocal Fold ◽  
Vocal Tract ◽  
Driving Forces ◽  
Vibrational Amplitude ◽  
Subglottal Pressure ◽  
Vertical Displacements ◽  
Vocal Intensity ◽  
Tissue Deformations ◽  
Chest Voice ◽  
Phase Differences

The myoelastic-aerodynamic theory of phonation has been quantified and tested with mathematical models. The models suggest that vocal fold oscillation is produced as a result of asymmetric forcing functions over closing and opening portions of the glottal cycle. For nearly uniform tissue displacements, as in falsetto voice, the asymmetry in the driving forces can result from the inertia of the air moving through the glottis. This inertia can in turn be enhanced or suppressed by supraglottal or subglottal vocal tract coupling. More obvious and pronounced asymmetries in the driving forces are associated with non-uniform vocal fold tissue displacements. These are combinations of normal tissue modes, and can result in vertical and horizontal phase differences along the surfaces, as observed in chest voice. The ranges of oscillation increase among various models as more freedom in the simulated tissue movement is incorporated. Of particular significance in initiating and maintaining oscillation are the vertical motions that facilitate coupling of aerodynamic energy into the tissues and allow tissue deformations under conditions of incompressibility. Vertical displacements also can have a significant effect on vocal tract excitation. Control of fundamental frequency of oscillation (FO) is basically myoelastic, partially as a result of deliberate or reflex adjustments of laryngeal muscles, and partially as a result of nonlinear tissue strain over the vibrational cycle. This places limits on the control of FO by subglottal pressure, and forces such control to be inseparably connected with vibrational amplitude, or less directly, with vocal intensity.

Friedel'S law breakdown and interpretation of stacking fault images in tetrahedral semiconductors

1987 ◽  
Vol 45 ◽  
pp. 318-319
Author(s):  
Rob. W. Glaisher ◽  
A.E.C. Spargo
Keyword(s):  
Relative Phase ◽  
Point Group ◽  
Binary Compound ◽  
Stacking Fault ◽  
Fold Axis ◽  
Atom Pair ◽  
Tetrahedral Semiconductors ◽  
Group Symmetries ◽  
Thin Crystal ◽  
Phase Differences

Images of <11> oriented crystals with diamond structure (i.e. C,Si,Ge) are dominated by white spot contrast which, depending on thickness and defocus, can correspond to either atom-pair columns or tunnel sites. Olsen and Spence have demonstrated a method for identifying the correspondence which involves the assumed structure of a stacking fault and the preservation of point-group symmetries by correctly aligned and stigmated images. For an intrinsic stacking fault, a two-fold axis lies on a row of atoms (not tunnels) and the contrast (black/white) of the atoms is that of the {111} fringe containing the two-fold axis. The breakdown of Friedel's law renders this technique unsuitable for the related, but non-centrosymmetric binary compound sphalerite materials (e.g. GaAs, InP, CdTe). Under dynamical scattering conditions, Bijvoet related reflections (e.g. (111)/(111)) rapidly acquire relative phase differences deviating markedly from thin-crystal (kinematic) values, which alter the apparent location of the symmetry elements needed to identify the defect.

Assessment of Tongue Position and Laryngeal Height in Two Professional Voice Populations

2020 ◽  
Vol 63 (1) ◽  
pp. 109-124
Author(s):  
Carly Jo Hosbach-Cannon ◽  
Soren Y. Lowell ◽  
Raymond H. Colton ◽  
Richard T. Kelley ◽  
Xue Bao
Keyword(s):  
Vocal Fold ◽  
Vocal Tract ◽  
Current Knowledge ◽  
Acoustic Resonance ◽  
Contact Dynamics ◽  
Voice Disorder ◽  
Music Program ◽  
Tongue Position ◽  
Singer Groups ◽  
Professional Voice

Purpose To advance our current knowledge of singer physiology by using ultrasonography in combination with acoustic measures to compare physiological differences between musical theater (MT) and opera (OP) singers under controlled phonation conditions. Primary objectives addressed in this study were (a) to determine if differences in hyolaryngeal and vocal fold contact dynamics occur between two professional voice populations (MT and OP) during singing tasks and (b) to determine if differences occur between MT and OP singers in oral configuration and associated acoustic resonance during singing tasks. Method Twenty-one singers (10 MT and 11 OP) were included. All participants were currently enrolled in a music program. Experimental procedures consisted of sustained phonation on the vowels /i/ and /ɑ/ during both a low-pitch task and a high-pitch task. Measures of hyolaryngeal elevation, tongue height, and tongue advancement were assessed using ultrasonography. Vocal fold contact dynamics were measured using electroglottography. Simultaneous acoustic recordings were obtained during all ultrasonography procedures for analysis of the first two formant frequencies. Results Significant oral configuration differences, reflected by measures of tongue height and tongue advancement, were seen between groups. Measures of acoustic resonance also showed significant differences between groups during specific tasks. Both singer groups significantly raised their hyoid position when singing high-pitched vowels, but hyoid elevation was not statistically different between groups. Likewise, vocal fold contact dynamics did not significantly differentiate the two singer groups. Conclusions These findings suggest that, under controlled phonation conditions, MT singers alter their oral configuration and achieve differing resultant formants as compared with OP singers. Because singers are at a high risk of developing a voice disorder, understanding how these two groups of singers adjust their vocal tract configuration during their specific singing genre may help to identify risky vocal behavior and provide a basis for prevention of voice disorders.

Update: Behavioral Management of Unilateral Vocal Fold Paralysis and Paresis

2019 ◽  
Vol 4 (3) ◽  
pp. 474-482
Author(s):  
Sarah L. Schneider
Keyword(s):  
Vocal Fold ◽  
Treatment Plan ◽  
Traumatic Injury ◽  
Voice Therapy ◽  
Valuable Insight ◽  
Behavioral Management ◽  
Use Patterns ◽  
Vocal Quality ◽  
And Function ◽  
Voice Use

PurposeVocal fold motion impairment (VFMI) can be the result of iatrogenic or traumatic injury or may be idiopathic in nature. It can result in glottic incompetence leading to changes in vocal quality and ease. Associated voice complaints may include breathiness, roughness, diplophonia, reduced vocal intensity, feeling out of breath with talking, and vocal fatigue with voice use. A comprehensive interprofessional voice evaluation includes auditory-perceptual voice evaluation, laryngeal examination including videostroboscopy, acoustic and aerodynamic voice measures. These components provide valuable insight into laryngeal structure and function and individual voice use patterns and, in conjunction with stimulability testing, help identify candidacy for voice therapy and choice of therapeutic techniques.ConclusionA comprehensive, interprofessional evaluation of patients with VFMI is necessary to assess the role of voice therapy and develop a treatment plan. Although there is no efficacy data to support specific voice therapy techniques for treating VFMI, considerations for various techniques are provided.

Pediatric Benign Vocal Fold Lesions: A Team Approach

2009 ◽  
Vol 19 (3) ◽  
pp. 105-112 ◽  
Author(s):  
Geralyn Harvey Woodnorth ◽  
Roger C. Nuss
Keyword(s):  
Vocal Fold ◽  
Evaluation Process ◽  
Team Approach ◽  
Speech Language Pathologist ◽  
Benign Vocal Fold Lesions ◽  
Different Types ◽  
Team Evaluation ◽  
Surgical Treatments ◽  
Review Current ◽  
Vocal Fold Nodules

Abstract Many children with dysphonia present with benign vocal fold lesions, including bilateral vocal fold nodules, cysts, vocal fold varices, and scarring. Evaluation and treatment of these children are best undertaken in a thoughtful and coordinated manner involving both the speech-language pathologist and the otolaryngologist. The goals of this article are (a) to describe the team evaluation process based on a “whole system” approach; (b) to discuss etiological factors and diagnosis; and (c) to review current medical, behavioral, and surgical treatments for children with different types of dysphonia.

Visco-elastic changes of vocal fold mucosa related to high and low relative air humidity

2000 ◽  
Vol 25 (4) ◽  
pp. 329-330
Author(s):  
R.J.B. Hemler ◽  
G.H. Wieneke ◽  
P.H. Dejonckere
Keyword(s):  
Vocal Fold ◽  
Air Humidity ◽  
Relative Air Humidity
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