OBJETIVO: Comparar a viscosidade dinâmica da camada superficial da fáscia temporal com a de outros tecidos biológicos tradicionalmente utilizados em implantes de pregas vocais para o tratamento de rigidez de pregas vocais. DESENHO DO ESTUDO: Experimental. MÉTODO: Amostras de camada superficial da fáscia temporal, camada profunda da fáscia temporal e gordura abdominal de 12 cadáveres são submetidas a medição de viscosidade dinâmica. RESUTADOS: A viscosidade dinâmica das diferentes amostras apresenta-se na seguinte ordem crescente: camada superficial da fáscia temporal, camada profunda da fáscia temporal e gordura abdominal. Observa-se diferença estatística na comparação entre todas as amostras. DISCUSSÃO: Quanto maior for a viscosidade da mucosa da prega vocal, maior é a pressão subglótica necessária para se iniciar a fonação. Dessa maneira, um bom material implantável em lâmina própria de prega vocal deve ter baixa viscosidade. Por esse parâmetro, a camada superficial da fáscia temporal é um material promissor para implantação em pregas vocais. CONCLUSÃO: A viscosidade dinâmica da camada superficial da fáscia temporal é menor que a da camada profunda da fáscia temporal e que a da gordura abdominal. / OBJECTIVE: To compare the dynamic viscosity of superficial layer of temporalis fascia with that of other biological tissues traditionally used for vocal fold implants to treat vocal fold rigidity. STUDY DESIGN: Experimental. METHOD: Measurement of dynamic viscosity of samples of superficial layer of temporalis fascia, deep layer of temporalis fascia and abdominal fat of 12 cadavers are performed. RESULTS: Dynamic viscosity values of the different samples are presented in the following increasing order: superficial layer of temporalis fascia, deep layer of temporalis fascia and abdominal fat. There is statistical difference among all the samples. CONCLUSION: Dynamic viscosity of superficial layer of temporalis fascia is lower than the ones of deep layer of temporalis fascia and abdominal fat.

Les travaux de cette thèse portent sur la compréhension des phénomènes physiques sous-jacents à la production normale ou pathologique de la voix. Certaines formes de pathologies pouvant concerner des affections structurelles des cordes vocales (polypes, paralysie, ...) et altérer de façon plus ou moins conséquente la mise en vibration des cordes vocales. Une partie de ces travaux porte ainsi sur l'observation expérimentale de la production de parole pathologique, grâce notamment à la mise au point d'une maquette auto-oscillante de cordes vocales artificielles. Celle-ci reprend la structure de latex remplie d'eau sous pressions des maquettes déjà développées au Gipsa-lab mais permet une plus grande indépendance des paramètres de contrôle. Un accent particulier des manipulations expérimentales est également porté sur la caractérisation mécanique des structures vibrantes, dont la connaissance est indispensable à la reproductibilité et la répétabilité des mesures ultérieures sur la maquette, ainsi qu'à l'analyse des résultats expérimentaux avec couplage aéroacoustique et la validation de modèles numériques associés.D'un côté, un calcul du comportement vibratoire des maquettes basée sur une méthode éléments finis a été mise oeuvre. Le modèle numérique développé utilise ainsi une formulation du couplage hydro-élastique entre le latex et l'eau qui constituent les maquettes et offre la possibilité de prendre en compte les grandes déformations et les pré-contraintes liées au gonflement du latex soumis à une forte pression d'eau. Finalement, un modèle d'écoulement glottique couplé à un modèle mécanique distribué de type "masse-raideur" a été utilisé et étendu pour simuler des comportements pathologiques tels que des asymétries (entre les deux cordes vocales et au sein d'une corde) ou la présence d'une masse ajoutée (kyste, polype). Un procédure d'optimisation de ce modèle sur une configuration expérimentale de référence permet alors de comparer les calculs aux observations des seuils d'oscillation sur les maquettes en présence d'une masse ajoutée. / My PhD work has focused on understanding physical phenomena related to speech production in healthy and pathological conditions. Some pathologies affect the structure of the vocal folds which could lead to a more or less substantial alteration of their vibrations. Part of this work is experimental modeling of speech production applied to pathologies, with the development of a self-oscillating vocal fold replica. This replica is made of water-filled latex, such as have already been developed at Gipsa-lab, but it allows a larger independence within its control parameters and it can be used to reproduce pathological conditions. A particular interest is brought to mechanical characterization of these vibrating structures. This characterization is of primary importance when it comes to repeatability and reproducibility of measurements, as for the analysis of experimental results with aeroacoustic coupling and the validation and improvements of corresponding numerical models.Simulations of the vocal fold vibrating behavior based on the finite element method have been developed. The model uses a formulation of the hydro-elastic coupling between the latex and the water which the replica is made of. It also offers the possibility to take into account the large deformations and the prestress within the latex induced by water pressure. Another numerical approach is made using a theoretical laryngeal flow model coupled with a distributed mass-spring model and a set of resonators. Calculations of the dynamical system stability offer the possibility for comparisons with the experimental setup through a finite set of parameters. This model is adapted to simulate pathological conditions such as asymmetries and the presence of growths (cysts, polyps). Finally, an optimization calculation of this model on an experimental reference configuration of the replica allows us to compare the calculations with the measurements on this replica with the presence of a polyp.

OBJETIVO: Comparar a viscosidade dinâmica da camada superficial da fáscia temporal com a de outros tecidos biológicos tradicionalmente utilizados em implantes de pregas vocais para o tratamento de rigidez de pregas vocais. DESENHO DO ESTUDO: Experimental. MÉTODO: Amostras de camada superficial da fáscia temporal, camada profunda da fáscia temporal e gordura abdominal de 12 cadáveres são submetidas a medição de viscosidade dinâmica. RESUTADOS: A viscosidade dinâmica das diferentes amostras apresenta-se na seguinte ordem crescente: camada superficial da fáscia temporal, camada profunda da fáscia temporal e gordura abdominal. Observa-se diferença estatística na comparação entre todas as amostras. DISCUSSÃO: Quanto maior for a viscosidade da mucosa da prega vocal, maior é a pressão subglótica necessária para se iniciar a fonação. Dessa maneira, um bom material implantável em lâmina própria de prega vocal deve ter baixa viscosidade. Por esse parâmetro, a camada superficial da fáscia temporal é um material promissor para implantação em pregas vocais. CONCLUSÃO: A viscosidade dinâmica da camada superficial da fáscia temporal é menor que a da camada profunda da fáscia temporal e que a da gordura abdominal. / OBJECTIVE: To compare the dynamic viscosity of superficial layer of temporalis fascia with that of other biological tissues traditionally used for vocal fold implants to treat vocal fold rigidity. STUDY DESIGN: Experimental. METHOD: Measurement of dynamic viscosity of samples of superficial layer of temporalis fascia, deep layer of temporalis fascia and abdominal fat of 12 cadavers are performed. RESULTS: Dynamic viscosity values of the different samples are presented in the following increasing order: superficial layer of temporalis fascia, deep layer of temporalis fascia and abdominal fat. There is statistical difference among all the samples. CONCLUSION: Dynamic viscosity of superficial layer of temporalis fascia is lower than the ones of deep layer of temporalis fascia and abdominal fat.

INTRODUÇÃO: O grande desafio para o laringologista perante o quadro de paralisia unilateral do músculo cricotireoideo é fazer o diagnóstico do comprometimento desse músculo por meio da laringoscopia. Não existe consenso na literatura em relação aos achados vibratórios que possam servir como comprovação dessa condição. O objetivo desse estudo foi avaliar os efeitos da contração do músculo cricotireoideo sobre a vibração das pregas vocais usando a videolaringoscopia de alta velocidade e tentar encontrar um ou mais achados que pudessem ser utilizados como um sinal indicativo de paralisia unilateral do músculo cricotireoideo. MÉTODOS: Realizou-se um estudo experimental com 20 laringes excisadas de cadáveres humanos adultos masculinos. A vibração cordal foi produzida artificialmente com a passagem de ar comprimido através das pregas vocais. Cada laringe foi avaliada em três situações: contração bilateral do músculo cricotireoideo, contração unilateral do músculo cricotireoideo e ausência de contração de ambos os músculos cricotireoideos. Os seguintes parâmetros foram avaliados pela videolaringoscopia de alta velocidade: frequência fundamental, periodicidade da vibração, amplitude de vibração das pregas vocais e simetria de fase entre as pregas vocais. RESULTADOS: A diminuição da tensão longitudinal das pregas vocais decorrente da ausência de contração do músculo cricotireoideo unilateral e bilateral mostrou não alterar a periodicidade da vibração e a presença de assimetria de fase entre as pregas vocais, mas houve uma diminuição significativa da frequência fundamental (p < 0,001). Observou-se, também, um aumento da amplitude de vibração das pregas vocais direita e esquerda (p < 0,05), que apresentaram comportamento semelhante para esse parâmetro nas diferentes situações estudadas. CONCLUSÕES: A diminuição da tensão nas pregas vocais, causada pela ausência da contração do músculo cricotireoideo unilateral e bilateral, resultou em uma diminuição da frequência fundamental e em um aumento da amplitude de vibração. A presença de periodicidade em todas as laringes sugere que a videoestrobolaringoscopia, método usado mais frequentemente na prática clínica, possa ser um método adequado para avaliar pacientes com paralisia unilateral do músculo cricotireoideo. E, finalmente, os resultados sugerem que a paralisia unilateral do músculo cricotireoideo parece não ser capaz de produzir uma assimetria de tensão suficiente para induzir diferença de amplitude de vibração e de fase entre as pregas vocais e, desta forma, esses parâmetros não podem ser utilizados para fazer uma diferenciação segura dessa condição / INTRODUCTION: The great challenge for laryngologists dealing with cricothyroid muscle paralysis is to diagnose impaired cricothyroid muscle function using laryngoscopy. There is no consensus in the literature on the vibratory findings that can be used as a proof of this condition. The aim of this study was to evaluate the effects that cricothyroid muscle contraction has on vocal fold vibration as evaluated with high-speed videoendoscopy, and to identify one or more aspects of the vocal fold vibration that could be used as an indicator of unilateral cricothyroid muscle paralysis. METHODS: We conducted an experimental study on 20 larynges excised from adult male human cadavers. Laryngeal vibration was artificially produced by compressed air passing through the vocal folds. Each larynx was assessed in three situations: bilateral cricothyroid muscle contraction, unilateral cricothyroid muscle contraction and no contraction of either cricothyroid muscle. The following parameters were evaluated by high-speed videoendoscopy: fundamental frequency, periodicity, amplitude of vocal fold vibration, and phase symmetry between the vocal folds. RESULTS: Although neither unilateral nor bilateral cricothyroid muscle contraction altered periodicity of vibration or the occurrence of phase asymmetry, there was a significant decrease in fundamental frequency in parallel with the decreasing longitudinal tension (p < 0,001). We also found an increase in vibration amplitude of right and left vocal folds (p < 0,05), which were similar in terms of their behavior for this parameter in the various situations studied. CONCLUSION: Decreased vocal fold tension caused by the absence of unilateral or bilateral contraction of cricothyroid muscle resulted in a decrease in fundamental frequency and an increase in vibration amplitude. The presence of regular periodicity in all studied larynges suggests that videostroboscopy, method most frequently used in clinical practice, may be a suitable method for the evaluation of patients with unilateral cricothyroid muscle paralysis. We also believe that unilateral cricothyroid muscle paralysis is not capable of causing a sufficient degree of tension asymmetry to induce phase asymmetry or a difference in vibration amplitude between the vocal folds and, hence, these parameters can\'t be used as reliable indicators of this condition

Master´s thesis deals with creating planar computational model of human folds, involving fluid-structure interaction. With this model, the influence of changes in vocal folds tissue layers (stiffness, thickness) and their effects on the videokymograph image are studied. Analysis of the results also deals with the evaluation of pressure at selected points below, between and above the vocal folds. The results indicate a possible similarity with the behavior of human vocal folds with pathology. Background research of vocal folds function, an overview of vocal folds pathology and summary of computational models are included.

This Master´s thesis deals with use of finite element method for modeling motion and stress of vocal folds during setting to phonation position. The thesis contains a description of the relevant anatomical structures and of the closely related formation of the human voice. A list of some previously published models of the function of human vocal folds follows. A part of my work was to create a model of geometry of the larynx using CATIA V5 and PTC Creo 2.0 on the basis of data acquired by MRI (magnetic resonance imaging). After that the model was converted into the calculation system Ansys Workbench 15.0 and, for solving contact problems, into Ansys Classic 15.0. To solve given problems, these programs use the finite element method (FEM). Solution was carried out for six different variants simulating individual motions of cartilages, corresponding to the activation of individual muscles. For each variant, the movements and stresses in the soft tissue of the vocal folds were evaluated. For variants with activation of IA, TA and LCA muscle it was also evaluated the contact pressure between the vocal folds. Finally, the thesis mentions the preparation of the model for the activation of the vocal folds movement by the muscles of the larynx.

No description available.

Computational models of the flow-induced vibrations of the vocal folds are powerful tools that can be used in conjunction with physical experiments to better understand voice production. This thesis research has been performed to contribute to the understanding of vocal fold dynamics as well as several aspects of computational modeling of the vocal folds. In particular, the effects of supraglottal geometry have been analyzed using a computational model of the vocal folds and laryngeal airway. In addition, three important computational modeling parameters (contact line location, Poisson's ratio, and symmetry assumptions) have been systematically varied to determine their influence on model output. Variations in model response were quantified by comparing glottal width, frequency, flow rate, open quotient, pressures, and wave velocity measures. In addition, the glottal jet was qualitatively analyzed. It was found that for various supraglottal geometries (either symmetrically or asymmetrically positioned), there was little asymmetry of the vocal fold motion despite significant asymmetry in the glottal jet. In addition, the vocal fold motion was most symmetric when consistent jet deflection was present (even if asymmetric). Inconsistent deflection of the glottal jet led to slightly larger asymmetries in vocal fold motion. The contact line location was found to have minimal impact on glottal width, frequency, and flow rate. The largest influence of the contact line location was seen in predicted velocity fields during the closed phase and in the pressure profiles along the vocal fold surfaces. Variations in Poisson's ratio strongly affected vocal fold motion, with lower Poisson's ratios resulting in larger amplitudes. The model did not vibrate when a Poisson's ratio of 0.49999 was used. The response of a full model (with two vocal folds) was shown to vary slightly from that of a half model (one vocal fold and a symmetry boundary condition), the greatest difference being in the deflection and dissipation of the glottal jet. It was concluded that for many scenarios the half model will be sufficient for modeling vocal fold motion; however, a full model is suggested for studies of material asymmetry or glottal jet dynamics. Application of these results to computational models of the vocal folds will lead to improved modeling and understanding of vocal fold dynamics.

Voice quality is strongly linked to quality of life; those who suffer from voice disorders are adversely affected in their social, family, and professional relationships. An effort has been made to more fully understand the physics behind how the voice is created, specifically the fluid structure interactions that occur during vocal fold vibration. Many techniques have been developed and implemented to study both the motion of the vocal folds and the airflow that creates the motion. Until recently these techniques have sought to understand a highly three-dimensional phenomenon with 1D or 2D perspectives.This research focuses on the development and implementation of an experimental technique to obtain three-dimensional characterizations of vocal fold motion and fluid flow. Experiments were performed on excised human vocal fold models at the University Hospital Erlangen Medical School in Erlangen, Germany. A novel technique for tracking the motion of the vocal folds using multiple camera viewpoints and limited user interaction was developed. Four high-speed cameras (2000 fps) recorded an excised vocal fold model vibrating at 250 Hz. Based on the images from these four cameras a fully 3D reconstruction of the superior surface of the vocal folds was achieved. The 3D reconstruction of 70 consecutive time steps was assembled to characterize the motion of the vocal folds over eight cycles. The 3D reconstruction accurately modeled the observed behavior of vocal fold vibration with a clearly visible mucosal wave. The average reprojection error for this technique was on par with other contemporary techniques (~20 micrometers). A whole field, time resolved, three-dimensional reconstruction of the vocal fold fluid flow was obtained using synthetic aperture particle image velocimetry. Simultaneous 3D flow fields, subglottal pressure waves, and superior surface motion were presented for 2 consecutive cycles of oscillation. The vocal fold fluid flow and motion measurements correlated with behavior observed in previous three-dimensional studies. A higher resolution view of one full cycle of oscillation was compiled from 16 time resolved data sets via pressure data. The result was a full three-dimensional characterization of the evolution and disintegration of the glottal jet.

Introduction: Exercise-induced laryngeal obstruction (EILO) is a condition associated with stridor, wheezing and dyspnea during exercise. The condition is commonly divided into two subtypes, glottic and supraglottic, depending on the level of the obstruction in the larynx. The obstruction may also occur in a combined form. At Uppsala University Hospital there are a few different treatment options for EILO but they are most commonly referred to speech and language pathology treatment (SLP-treatment).    Objectives: The purpose of this study was to examine (1) the perceived effect of SLP-treatment on individuals with EILO and (2) to examine whether a difference in the perceived effect was due to type of EILO. A third aim (3) was to examine the presence of voice symptoms in this group.   Study designs:This study investigated separate objectives and reported results from both a retrospective cross-sectional study and a cross-sectional study.    Methods:51 participants with EILO were referred to SLP-treatment between year 2007 and 2017. 37 of the participants completed a survey on the perceived effect of SLP-treatment. All participants answered a questionnaire about voice symptoms, Screen6.   Results: A majority, 54% of the 37 participants who had undergone SLP-treatment, reported being helped by the treatment. In total, 51 participants diagnosed with EILO answered the survey, generating a response rate of 52%. The result showed that 31 % of the participants reported voice problems. Voice problems were defined as having two or more voice symptoms weekly or daily on Screen6.    Conclusions:(1) In this study a majority of the participants reported SLP-treatment as helpful. (2) No significant difference between the perceived effect of the intervention and type of EILO existed. (3) 31% of the participants had a voice problem according to Screen6. This number is higher, than in the general population and in other risk groups and may indicate a greater risk of voice disorders in individuals with EILO.