2B using an isotropic vocal fold model, and the other is to stiffen the vocal fold in the AP direction (in either the body or cover layer or both layers), which is considered in Sec. The effect on the vocal fold stiffness, eigenfrequencies and eigenmodes, fundamental frequencies, glottal flow rate, vocal fold vibratory dynamics, and synchronization of the eigenmodes were analyzed by using the structure eigen analysis and flow-structure interaction simulations. According to Hirano s cover-body theory of vocal fold vibra-tion, the epithelium and the SLP constitute the cover, the vocalis muscle acts as the body, and the intermediate and deep layers of the lamina propria, which make up the vocal ligament, are the transition layer [ ]. The underlying structure of the lamina propria consists of extracellular matrix, collagen and elastin fibers [ 2 , 5 , 6 ]. eCollection 2020. Generally speaking, the vocal folds open up from bottom to top and from back to front. In 1974, Minoru Hirano proposed his theory of voice production that is now known as the cover–body theory. The influence of vocal fold geometry and stiffness on phonation onset was experimentally investigated using a body-cover physical model of the vocal folds. In 1974, Minoru Hirano proposed his theory of voice production that is now known as the cover–body theory. For each vocal fold, the model uses one mass for the body, two mass for the cover, coupled by a linear spring, and, on the fold affected by the lesion (the right fold was arbitrarily chosen), e cover layer is considered important, as it is mainly involved in the normal Preliminaries to the body-cover theory of pitch control. - vocal folds are composed of a cover and a body-sometimes only the cover is set into vibration, only the body, or both The 2017 Oct;142(4):2311. doi: 10.1121/1.5008497. Resonance Effects and the Vocalization of Speech. Fully automatic segmentation of glottis and vocal folds in endoscopic laryngeal high-speed videos using a deep Convolutional LSTM Network. 51, 1233-1268 (1972)] has been extended to a three-mass model in order to more realistically represent the body-cover vocal-fold structure [M. Hirano, Folia Phoniar. Enter words / phrases / DOI / ISBN / authors / keywords / etc. The cover-body thickness ratio of a three-layer vocal fold was systematically varied. The classic two‐mass model of the vocal folds [K. Ishizaka and J. L. Flanagan, Bell Syst. Clipboard, Search History, and several other advanced features are temporarily unavailable. This process has been superbly modelled mathematically by Ingo Titze [ Tize 1994 ], and forms the basis of our understanding of the dynamics of voice production today. The body mass, which represents muscle tissue, is further coupled laterally to a rigid wall (assumed to represent the thyroid cartilage) by a nonlinear spring and a damping element.  |  A simple, low‐dimensional model of the body‐cover vocal‐fold structure is proposed as a research tool to study both normal and pathological vocal‐fold vibration. Epub 2014 Jul 5. J Acoust Soc Am.  |  The closing of the vocal folds also proceeds from bottom to top, but along the horizontal axis it starts from the middle, closing forwards and backwards at the same time. J Acoust Soc Am. Biomechanical features (35–46) are intended to estimate the mass and, overall, the stiffness in the body and the cover of the vocal folds, as well as their instability. It also serves as a lubricator during sound production. Cover is the lamina propria and epithelium. However, deeper vocal fold tissues - collagen, elastin and muscle - exhibit some resistance to stretching, but can become quite stiff. 26, 89-94 (1974)]. A simple, low-dimensional model of the body-cover vocal-fold structure is proposed as a research tool to study both normal and pathological vocal-fold vibration. ... interrupt the vibratory patterns of the vocal fold by increasing the mass and reducing the pliability of the overlying cover (ie, cover/body theory of vocal fold vibration), as well as by impeding proper closure of … The body-cover model of phonation facilitated an explanation of F0 control based on tension or stiffness of the vocal fold. J. Website © 2020 AIP Publishing LLC. The role of the individual laryngeal adductors (thyroarytenoid [TA] vs. LCA) in ... control of vocal fold cover stiffness remains to be further elucidated. Laryngoscope, 119:222–227, 2009 INTRODUCTION The ability to … 2014 Nov;28(6):657-67. doi: 10.1016/j.jvoice.2014.03.001. Remember, it wasn't until the middle 1970s that this theory was widely accepted. Tech. Benign vocal fold lesions have varying amounts of inflammatory products, collagen de- Mathematical body-cover model of vocal folds with a polyp The proposed model adapts the structure presented in [9] into the three-mass body-cover model of vocal folds described in [21]. 1. The body-cover model of the vocal folds' structure is used for the modelling of vocal fold vibration (see section 27.3). The epithelium, the thin skin that covers the vocal fold, is a loose material that can't hold much tension. He described the thyroarytenoid (TA) and cricothyroid (CT) muscles as the major determinants of vocal fold shape and stiffness, and theorized four typical laryngeal configurations resulting from unique TA/CT activations, with implications for the resulting voice quality. Key Words: Shear modulus, vocal fold, viscoelasticity, LSR, larynx. Identification of geometric parameters influencing the flow-induced vibration of a two-layer self-oscillating computational vocal fold model. Effect of vocal fold stiffness on voice production in a three-dimensional body-cover phonation model. Article copyright remains as specified within the article. Epub 2020 Feb 13. In this model, cover layer stiffness is primarily responsible for F0 control and the TA and the cricothyroid (CT) muscles change the stiffness of the cover layer by altering its length. J Acoust Soc Am. In humans, these two approaches roughly correspond to activation of the TA and CT … 2002 Sep;112(3 Pt 1):1064-76. doi: 10.1121/1.1496080. HHS 2020 Feb 10;15(2):e0227791. According to Hirano’s cover-body theory of vocal fold vibration, the epithelium and the SLP constitute the “cover,” the vocalis muscle acts as the “body,” and the intermediate and deep layers of the lamina propria, which make up the vocal ligament, are the “transition” layer [11 1. You grow a new vocal fold cover every 4 days! J. Tokyo, University of Tokyo Press, 1981:271-88 3. But only if you give your voice a chance to rest and restore. The manner and frequency (pitch & loudness) of vibration can be modified by the intrinsic laryngeal muscles What is the Body Cover Theory? The transition zone is the vocal ligament. doi: 10.1371/journal.pone.0227791. It maintains the simplicity of a two‐mass model but allows for physiologically relevant adjustments and separate vibration of the body and the cover. The underlying structure of the lamina propria consists of extracellular matrix, collagen and elastin fibers [2, 5, 6]. doi: 10.1121/10.0001276. Tech. Jiang W, Rasmussen JH, Xue Q, Ding M, Zheng X, Elemans CPH. Selecting this option will search all publications across the Scitation platform, Selecting this option will search all publications for the Publisher/Society in context, Department of Speech Pathology and Audiology and The National Center for Voice and Speech, The University of Iowa, Iowa City, Iowa 52242. J Voice. It maintains the simplicity of a two‐mass model but allows for physiologically relevant adjustments and separate vibration of the body and the cover. Clinical significance Lesions. Since the cover model accounts only for the cover and not the body, it makes sense that it would not explain situations involving activity in both the body and the cover. Fehling MK, Grosch F, Schuster ME, Schick B, Lohscheller J. PLoS One. It maintains the simplicity of a two-mass model but allows for physiologically relevant adjustments and separate vibration of the body and the cover. consists of a body (a deep layer of lamina propria and muscle) and a cover (epithelium plus superficial and intermediate layers of the lamina propria). It maintains the simplicity of a two-mass model but allows for physiologically relevant adjustments and separate vibration of the body and the cover. Rules for controlling low-dimensional vocal fold models with muscle activation. Objectives/Hypothesis. The normal vocal fold is composed of five layers: the epithelium, the three layers of the lamina propria (superficial, intermediate, and deep), and the thyroarytenoid muscle. M. Hirano and Y. Kakita, “Cover-body theory of vocal fold vibrati… Chaos. In: Stevens KN, Hirano M, eds. The mucosal wave of the vocal folds is generated as the cover (the epithelium and superficial lamina propria) deforms over the body (the vocal fold ligament and vocalis muscle). 2009 Jun;19(2):023113. doi: 10.1063/1.3120293. The model consists of two "cover" masses coupled laterally to a "body" mass by nonlinear springs and viscous damping elements. cover-body theory of vocal fold vibration, in which the epithelium and superficial lam-ina propria act as a “cover” which vibrates over the “body” designated by the deeper tissue layers of the vocal fold (intermediate and deep layers of the lamina propria and vocalis muscle). The two cover springs are intended to represent the elastic properties of the epithelium and the lamina propria while the body spring simulates the tension produced by contraction of the thyroarytenoid muscle. If you need an account, please register here, The Journal of the Acoustical Society of America. A model that can,represent the body-cover structure of the vocal folds is an,extension of the two-mass model to the three-mass model,[16]. The soft vocal fold cover is pulled up, leading to closure that cuts of the airflow, enabling the tension in the underlying body to pull the cover back down. The body-cover theory of vocal fold vibration then relies on the myoelastic nature of the cover, the deformability or suppleness of this region. NLM 2020 Mar 3;117(9):4718-4723. doi: 10.1073/pnas.1922147117. This can be achieved in at least two ways: one is to stiffen the body layer, which is discussed in Sec. Epub 2019 Dec 5. ... Mucus is a viscous substance covering respiratory, digestive, and other systems in your body, including the vocal folds. High-fidelity continuum modeling predicts avian voiced sound production. Would you like email updates of new search results? Please enable it to take advantage of the complete set of features! Then, for the mechanical structure, we consider the body-cover model (BCM) proposed by Story & Titze (1995), where the bottom surfaces of cover masses, m 1 and m 2, are in contact with the intraglottal airflow through the surfaces S 1 and S 2, respectively. USA.gov. 1988;1(4):314-319 4. Prevention and treatment information (HHS). A simple, low-dimensional model of the body-cover vocal-fold structure is proposed as a research tool to study both normal and pathological vocal-fold vibration. The cover as we said, is the epithelium plus the superficial layer of the lamina propria. A simple, low‐dimensional model of the body‐cover vocal‐fold structure is proposed as a research tool to study both normal and pathological vocal‐fold vibration. Due to the assumed symmetry, the cover masses collide in the midsagittal … The physiologic concepts are based on the myoelastic-aerodynamic, body-cover, and mucosal wave theories. Histologically, the vocal fold is a complex structure. The vocal folds are set into vibration by changes in airflow and air pressure. The study of the behavior of the vocal muscle during phonation has made it possible to detect neurological anomalies such as … 2019 Dec 26;4(6):1637-1643. doi: 10.1044/2019_pers-19-00052. True Vocal Folds: Body - Cover Control: The body refers to the vocalis muscle and ligament. The reason for this is that part of the vocal fold body, the TA muscle itself, is vibrating when you produce low pitches or do especially loud singing. All these characteristics provide much information, as they depend directly on neuromotor control. The factors that regulate the vocal folds to produce pitch changes, intensity variation, and register effects are outlined. To sign up for alerts, please log in first. Energy-based fluid–structure model of the vocal folds ... Horáˇcek, 2018 ). Proc Natl Acad Sci U S A. This option allows users to search by Publication, Volume and Page. Since the basal lamina secures... Reinke's edema. Additionally, the two cover masses are coupled to each other through a linear spring which can represent vertical mucosal wave propagation. The delicate arrangement of the extracellular matrix proteins within the lamina propria permits passive movement of the epithelium, or vocal cover, over the body, resulting in the formation of the mucosal wave as air is passed through the glottis as a release of building subglottic pressure. Perspect ASHA Spec Interest Groups. Lowell SY, Story BH. Perspect ASHA Spec Interest Groups. This site needs JavaScript to work properly. All the elements,of this system have non-linear … Vocal fold nodules (VFNs), depicted in the video below, are localized, benign, superficial growths on the medial surface of the true vocal folds (TVFs) that are commonly believed to result from phonotrauma. It is the intermediate and deep layer. The classic two-mass model of the vocal folds [K. Ishizaka and J. L. Flanagan, Bell Syst. Fujimura O. Body-cover theory of the vocal fold and its phonetic implications. the cover-body model in that cricothyroid muscle ac-tivity generates a greater change in cover stiffness than laryngeal adductors. P60 DC00976/DC/NIDCD NIH HHS/United States.  The vibration of the vocal folds is a very complex movement. The vocal fold tissue is attached to the thyroid cartilage on the internal surface of the thyroid lamina just below the thyroid notch at a point called the anterior commissure. Effects of mucosal loading on vocal fold vibration. NIH Alzamendi GA, Manríquez R, Hadwin PJ, Deng JJ, Peterson SD, Erath BD, Mehta DD, Hillman RE, Zañartu M. J Acoust Soc Am. 13, 26 If the vocal folds were a simple single mass, the oscillation of the vocal folds as airflow through the glottis increases and then decreases could be described simplistically as … Selecting this option will search the current publication in context. The histological structure of the vocal fold can be separated into 5 or 6 tissues, depending on the source, which can then be grouped into three sections as the cover, the transition, and the body. J Voice. Simulations show reasonable similarity to observed vocal-fold motion, measured vertical phase difference, and mucosal wave velocity, as well as experimentally obtained intraglottal pressure. He described the thyroarytenoid (TA) and cricothyroid (CT) muscles as the major determinants of vocal fold shape and stiffness, and theorized four typical laryngeal configurations resulting from unique TA/CT activations, with implications for the resulting voice quality. THREE MASS MODEL Vocal folds consider as 3 interconnected masses First & largest mass - body of the vocal fold (thyroarytenoid muscle) Two smaller masses - upper and lower portions of the cover (lamina propria and epithelium) Glottis opens and closes asymmetrically with vertical phase difference from bottom to top. 2019 Dec;5(4):387-401. doi: 10.1007/s40883-018-0085-8. Mechanical characterization of vocal fold tissue: a review study. Titze IR, Jiang J, Drucker DG. An evaluation of the cover-body theory is explained in terms of pitch control. 2011 Apr;129(4):2121-32. doi: 10.1121/1.3557046. the vocal fold comprises an upper and lower part, each of them represented by a simple mechanical oscillator described by mass, stiffness (spring) and damping (m, s, r)

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