This thesis consists of five articles and a summary. Thethesis deals with methods for measuring properties of thevoice. The methods are all computer-based, but utilisedifferent approaches for measuring different aspects of thevoice. Paper I introduces the Visual Sort and Rate (VSR) method forperceptual rating of voice quality. The method is based on theVisual Analogue Scale (VAS), but simultaneously shows allstimuli as icons along the VAS on the computer screen. As thelistener places similar-sounding stimuli close to each otherduring the rating process, comparing stimuli becomeseasier. Paper II introduces the correlogram. Fundamental frequencyF0 sometimes cannot be strictly defined, particularly forperturbed voice signals. The method displays multipleconsecutive correlation functions in a grey scale image. Thus,the correlogram avoids selecting a single F0 value. Rather itpresents an unbiased image of periodicity, allowing theinvestigator to select among several candidates, ifappropriate. PaperIII introduces a method for detection of phonation tobe utilised in voice accumulators. The method uses twomicrophones attached near the subject’s ears. Phase andamplitude relations of the microphone signals are used to forma phonation detector. The output of the method can be used tomeasure phonation time, speaking time and fundamental frequencyof the subject, as well as sound pressure level of both thesubject’s voicing and the ambient sounds. Paper IV introduces a method for Fourier analysis ofhigh-speed laryngoscopic imaging. The data from the consecutiveimages are re-arranged to form time-series that reflect thetime-variation of light intensity in each pixel. Each of thesetime series is then analysed by means of Fouriertransformation, such that a spectrum for each pixel isobtained. Several ways of displaying these spectra aredemonstrated. Paper V examines a test set-up for simultaneous recording ofairflow, intra-oral pressure, electro-glottography, audio andhigh-speed imaging. Data are analysed with particular focus onsynchronisation between glottal area and inverse filteredairflow. Several methodological aspects are also examined, suchas the difficulties in synchronising high-speed imaging datawith the other signals. / QC 20100609

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A quantidade de mÃtodos nÃo invasivos de diagnÃstico tem aumentado devido à necessidade de exames simples, rÃpidos e indolores. Por conta do crescimento da tecnologia que fornece os meios necessÃrios para a extraÃÃo e processamento de sinais, novos mÃtodos de anÃlise tÃm sido desenvolvidos para compreender a complexidade dos sinais de voz. Este trabalho de dissertaÃÃo apresenta uma nova ideia para caracterizar os sinais de voz saudÃvel e patolÃgicos baseado em uma ferramenta matemÃtica amplamente conhecida na literatura, a Transformada Wavelet (WT). O conjunto de dados utilizado neste trabalho consiste de 60 amostras de vozes divididas em quatro classes de amostras, uma de indivÃduos saudÃveis e as outras trÃs de pessoas com nÃdulo vocal, edema de Reinke e disfonia neurolÃgica. Todas as amostras foram gravadas usando a vogal sustentada /a/ do PortuguÃs Brasileiro. Os resultados obtidos por todos os classificadores de padrÃes estudados mostram que a abordagem proposta usando WT à uma tÃcnica adequada para discriminaÃÃo entre vozes saudÃvel e patolÃgica, e apresentaram resultados similares ou superiores a da tÃcnica clÃssica quanto à taxa de reconhecimento. / The amount of non-invasive methods of diagnosis has increased due to the need for simple, quick and painless tests. Due to the growth of technology that provides the means for extraction and signal processing, new analytical methods have been developed to help the understanding of analysis of the complexity of the voice signals. This dissertation presents a new idea to characterize signals of healthy and pathological voice based on one mathematical tools widely known in the literature, Wavelet Transform (WT). The speech data were used in this work consists of 60 voice samples divided into four classes of samples: one from healthy individuals and three from people with vocal fold nodules, Reinkeâs edema and neurological dysphonia. All the samples were recorded using the vowel /a/ in Brazilian Portuguese. The obtained results by all the pattern classifiers studied indicate that the proposed approach using WT is a suitable technique to discriminate between healthy and pathological voices, since they perform similarly to or even better than classical technique, concerning recognition rates.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Microvascularization of human superior membranous vocal folds tends to be parallel to the long axis. This pattern of microvascularization changes with disease. The objective this study was to describe microvascular changes in the human vocal folds with polypoid alterations as differential diagnosis with other laryngeal diseases. A retrospective study was conducted to describe alterations in the microvasculature of the vocal folds of eleven patients having polyps, who underwent laryngeal microsurgery and subsequent rigid and contact laryngoscopy. To study the microvascular changes, D Ávila (2002) classification was used. The vocal folds were divided in three regions: superior membranous, superior cartilaginous, and subglottic. The twelve types of microvessels described by D Ávila were identified in the study and 74 altered microvessels were found; dilated parallel and branching micro vessels predominated. Our findings highlight that microvascularization of the vocal folds changes with polyp formation; and the presence of branching microvessels in the surface of vocal cord lesions suggests a diagnosis of polyp formation. / A microvascularização da face superior membranosa da prega vocal humana tende a ser paralela ao seu longo eixo. Este padrão de vascularização modifica-se na presença de patologias. O objetivo deste trabalho foi descrever as alterações microvasculares que ocorrem na prega vocal humana acometida por pólipo. Através de estudo retrospectivo foram descritas as alterações microvasculares que ocorreram nas pregas vocais de 11 pacientes de ambos os gêneros, portadores de pólipos, atendidos nas Clínicas de Dr. Jeferson D Ávila e Dr. Edilson Cunha e submetidos à microcirurgia da laringe e às endoscopias rígida e de contato da laringe. Para descrever as alterações microvasculares foi utilizada a classificação de D Ávila (2002) e as pregas vocais foram dividas em 3 faces: face superior membranosa, face superior cartilaginosa e face subglótica. Os 12 tipos de microvasos descritos por D Avila foram identificados neste estudo, tendo sido encontrados 74 microvasos alterados, havendo predominância dos microvasos paralelo ectásico e ramificado em rede. Nossos achados ressaltam que a microvascularização da prega vocal está alterada na presença de pólipo e que a presença de microvaso do tipo ramificado em rede na superfície de uma lesão única ou múltipla de prega vocal sugere fortemente a presença de pólipo de prega vocal.

The presented thesis is involved in the biomechanics of phonation. The aim of the thesis is to set a fluid-structure interaction between the vocal folds and air flow when the pressure from lungs reaches the physiological values. In the expected outcome the self-oscillating vocal folds should be observable with characteristics shape-shift from convergent to divergent. In theory part of the thesis is described Anatomy of the vocal tract, physiology of the human phonation, research of computational simulations, experiments and visualisation methods are described in the theory part of the thesis. In the second part, setup of computational simulation with the finite element method is presented. Besides of the fluid-structure interaction the acoustical model is set. Achieved results are presented and compared to the results in literature. Displacements are evaluated from the structural model and pressures, velocities and flow velocities are evaluated from fluid model, so as acoustics results.

Master thesis deals with creating of the numerical model of the human vocal folds. Calculation algorithm is designed to include vocal chordsinteraction with the air flow. Analysis of the results achieved by the numerical simulations and calculations are focused on the pressure and velocity conditions in the areas under vocal folds, between vocal folds and above vocal folds. Movement and stress analysis of individual layers of vocal folds has been made. This analysis is limited only for physiological health vocal folds without pathology and disease. Modal analysis of structural and acoustic environment, backround research of vocal folds function and summary of some published overviews of numerical models is part of this work.

The vocal folds are an essential component of human speech production and communication. Advancements in voice research allow for improved voice disorder treatments. Since in vivo analysis of vocal fold function is limited, models have been developed to simulate vocal fold motion. In this research, synthetic and computational vocal fold models were used to investigate various aspects of vocal fold vibratory characteristics. A series of tests were performed to quantify the effect of varying material and geometric parameters on the models' flow-induced responses. First, the influence of asymmetric vocal fold stiffness on voice production was evaluated using life-sized, self-oscillating vocal fold models with idealized vocal fold geometry. Asymmetry significantly influenced glottal jet flow, glottal area, and vibration frequency. Second, flow-induced responses of simplified and MRI-based synthetic models were compared. The MRI-based models showed remarkable improvements, including less vertical motion, alternating convergent-divergent glottal profile patterns, and mucosal wave-like movement. Third, a simplified model was parametrically investigated via computational modeling techniques to determine which geometric features influenced model motion. This parametric study led to identification and ranking of key geometric parameters based on their effects on various measures of vocal fold motion (e.g., mucosal wavelike movement). Incorporation of the results of these studies into the definition of future models could lead to models with more life-like motion.

The voice is the primary mode of communication for humans. Because the voice is so important, voice disorders tend to severely diminish quality of life. A better understanding of the physics of voice production can help to improve treatment of voice disorders. For this thesis research a self-oscillating synthetic vocal fold model was developed, compared with previous synthetic vocal fold models, and used to explore the physical effects of augmentation injections on vibration dynamics. The research was conducted in two stages. First, four vocal fold models were evaluated by quantifying onset pressure, frequency, maximum glottal gap, flow rate, and medial surface motion. The newly developed model, differentiated from the other models by the inclusion of more layers, adjusted geometry, and an extremely soft superficial lamina propria layer, was included in this study. One of the models, created using MRI-derived geometry, had the most defined mucosal wave. The newly-developed model had the lowest onset pressure, flow rate, and smallest maximum glottal width, and the model motion compared very well with published excised human larynx data. Second, the new model was altered to simulate bowing by decreasing the volume of the body layer relative to that of a normal, unbowed model. Two models with varying degrees of bowing were created and tested while paired with normal models. Pre- and post-injection data (onset pressure, vibration frequency, glottal flow rate, open quotient, and high-speed image sequences) were recorded and compared. General pre- to post-injection trends included decreased onset pressure, glottal flow rate, and open quotient, and increased vibration frequency. Additionally, there was a decrease in mucosal wave velocity and an increase in phase angle. The thesis results are anticipated to aid in better understanding the physical effects of augmentation injections, with the ultimate goal of obtaining more consistent surgical outcomes, and also to contribute to the advancement of voice research through the development of the new synthetic model.

Synthetic, self-oscillating vocal fold (VF) models are physical models whose life-like vibration is induced and perpetuated by fluid flow. Self-oscillating VF models, which are often fabricated life-size from soft silicone elastomers, are used to study various aspects of voice biomechanics. Despite their many advantages, the development and use of self-oscillating VF models is limited by the casting process used to fabricate the models. Consequently, this thesis focuses on the development of 3D printing processes for fabricating silicone VF models. A literature review is first presented which describes three types of material extrusion 3D printing processes for silicone elastomers, namely direct ink writing (DIW), embedded 3D printing, and removable-embedded 3D printing. The review describes each process and provides recent examples from literature that show how each has been implemented to create silicone prints. An embedded 3D printing process is presented wherein a set of multi-layer VF models are fabricated by extruding silicone ink within a VF-shaped reservoir filled with a curable silicone support matrix. The printed models successfully vibrated during testing, but lacked several desirable characteristics which were present in equivalent cast models. The advantages and disadvantages of using this fabrication process are explored. A removable-embedded 3D printing process is presented wherein shapes were fabricated by extruding silicone ink within a locally-curable support matrix then curing the silicone ink and proximate matrix. The printing process was used to fabricate several geometries from a variety of silicone inks. Tensile test results show that printed models exhibit relatively high failure strains and a nearly isotropic elastic modulus in directions perpendicular and parallel to the printed layers. A set of single-material VF models were printed and subjected to vibration testing. The printed models exhibited favorable vibration characteristics, suggesting the continued use of this printing process for VF model fabrication. A micro-slicing process is presented which is capable of creating gcode for 3D printing multiple materials in discrete and mixed ratios by utilizing a previously-sliced single-material shape and a material definition. An important advantage of micro-slicing is its ability to create gcode with a mixed-material gradient. Initial test results and observations are included. This micro-slicing process could be used in material extrusion 3D printing