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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Association between Laryngeal Airway Aperture and the Discharge Rates of Genioglossus Motor Units

LaCross, Amy, Watson, Peter J., Bailey, E. Fiona 25 January 2017 (has links)
We know very little about how muscles and motor units in one region of the upper airway are impacted by adjustments in an adjacent airway region. In this case, the focus is on regulation of the expiratory airstream by the larynx and how changes in laryngeal aperture impact muscle motor unit activities downstream in the pharynx. We selected sound production as a framework for study as it requires (i) sustained expiratory airflow, (ii) laryngeal airway regulation for production of whisper and voice, and (iii) pharyngeal airway regulation for production of different vowel sounds. We used these features as the means of manipulating expiratory airflow, pharyngeal, and laryngeal airway opening to compare the effect of each on the activation of genioglossus (GG) muscle motor units in the pharynx. We show that some GG muscle motor units (a) discharge stably on expiration associated with production of vowel sounds, (b) are exquisitely sensitive to subtle alterations in laryngeal airflow, and (c) discharge at higher firing rates in high flow vs. low flow conditions even when producing the same vowel sound. Our results reveal subtle changes in GG motor unit discharge rates that correlate with changes imposed at the larynx, and which may contribute to the regulation of the expiratory airstream.
2

Breathing and phonation : effects of lung volume and breathing behaviour on voice function

Iwarsson, Jenny 2001 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2001. Härtill 6 uppsatser.
3

A numerical and analytical study of phonation threshold pressure and experiments with a physical model of the vocal fold mucosa

Liu, Chen 1 September 2009 (has links)
No description available.
4

Whisper and Phonation: Aerodynamic Comparisons across Adduction and Loudness Levels

Konnai, Ramya Mohan 26 March 2012 (has links)
No description available.
5

Análise do padrão vibratório das pregas vocais em sujeitos com e sem nódulo vocal por meio de videolaringoscopia de alta velocidade Analysis of the vibrations of vocal folds in subjects with and without vocal nodule by means of High-speed videoendoscopy

Paula Belini Baravieira 20 January 2012 (has links)
O objetivo do presente trabalho foi analisar por meio da videolaringoscopia de alta velocidade o padrão vibratório das pregas vocais de indivíduos com e sem nódulo de prega vocal. Além disso, comparar o padrão vibratório das pregas vocais, de todos os grupos, analisado pela videolaringoscopia de alta velocidade com os resultados das análises acústica e quimográfica. Participaram deste estudo 36 indivíduos, do gênero feminino, com idades entre 18 e 45 anos, divididos em 3 grupos: grupo controle (GC), com 18 mulheres sem lesão nas pregas vocais e com vozes normais, grupo com nódulo vocal incipiente (GNI) com 8 mulheres com nódulo vocal incipiente e grupo com nódulo vocal (GN) composto por 10 mulheres com nódulo vocal de pequeno a grande. Procedimentos: gravação vocal, para análise acústica e perceptivo-auditiva, e exame laríngeo com a videolaringoscopia de alta velocidade para análise das imagens de alta velocidade (HSV) e da quimografia digital (DKG). Resultados: Encontraram-se tempos de fase do ciclo glótico semelhantes entre o grupo controle e o grupo com nódulo vocal incipiente, no entanto, significativamente menores do que os tempos de fase dos indivíduos com nódulo vocal, com exceção do tempo de fechamento. Observou-se também diferenças para o quociente de abertura (OQ), no grupo com nódulo vocal a proporção em que a prega vocal ficou aberta em um ciclo foi significativamente maior do que no grupo sem nódulo (OQ = 0,81 ± 0,07 e OQ = 0,68 ± 0,12, respectivamente). Além disso, por meio da quimografia digital pode-se observar que a amplitude de vibração das pregas vocais foi significativamente reduzida no grupo com nódulo vocal em relação aos indivíduos sem nódulo. Discussão e Conclusão: Concluiu-se neste trabalho, por meio da análise da videolaringoscopia de alta velocidade, que o padrão de vibração das pregas vocais foi regular em todos os grupos analisados, apresentando variações mínimas em relação ao período e à amplitude. Na comparação dos grupos, observou-se que o grupo com nódulo vocal apresentou redução da amplitude de vibração das pregas vocais em relação ao grupo controle. Além disso, no grupo com nódulo vocal o quociente de abertura indicou predomínio do tempo de fase aberta. Na comparação das metodologias empregadas concluiu-se que a videolaringoscopia de alta velocidade e a quimografia digital avaliam de forma distinta os tempos de fase do ciclo vibratório, e, consequentemente o quociente de abertura das pregas vocais, cujo cálculo é baseado nestes tempos de fase. Estes resultados alertam a necessidade de estabelecerem-se valores diferentes para a normalidade entre a videolaringoscopia de alta velocidade e a quimografia digital. This dissertation reports on the analysis of the vocal fold vibration pattern of subjects with and without vocal fold nodule by high-speed videoendoscopy. It also compares the pattern of vocal fold vibration in all groups analyzed with the results of acoustic and kymograph analyses. Thirty six women whose age ranged from 18 to 45 participated of the study. They were divided into 3 groups: control group (GC), with 18 women with no lesions on vocal folds; incipient vocal nodule group (GNI), composed of 8 women with incipient vocal nodule; and vocal nodule group (GN), composed of 10 women with a smallto-large vocal nodule. The procedures comprised voice recording for acoustic analysis and auditory-perceptual and highspeed videoendoscopy for high-speed image analysis and digital kymography (DKG). The results revealed phases of the vibration cycle (open phase, closed phase, opening phase and closing phase) similar to those of the control group and incipient vocal nodule group, but significantly lower than the phase times of the vibration cycle of vocal nodule group, except for the closing phase. Regarding the open quotient (OQ), in the group with vocal nodule the proportion at which the vocal fold was opened in a cycle was significantly higher than the control group (OQ = 0,81 ± 0,07 and OQ = 0,68 ± 0,12, respectively). The digital kymography allowed observing that the vibration amplitude of the vocal folds was significantly reduced in the group with vocal nodule in comparison to the control group. By means of the high-speed videoendoscopy analysis, it was possible to conclude that the pattern of vocal fold vibration was regular in all groups, with minor variations in the period and amplitude. By comparing the groups, the group with vocal nodule decreased the amplitude of vibration of the vocal folds in the control group. Moreover, in the group with vocal nodule the open quotient indicated predominance of the open phase. The comparison of the methodologies allowed concluding that high-speed videoendoscopy and digital kymography asses the time phase of the vibration cycle differently, and hence the open quotient the vocal folds, which is calculated based on these times of phase. The results emphasize the need to set up different values for the normality of high-speed videoendoscopy and digital kymography.
6

The Epilarynx in Speech

Moisik, Scott 2013 (has links)
This dissertation examines the phonetic and phonological functioning of the supraglottal part of the larynx, the epilarynx, from an articulatory-physiological perspective. The central thesis is that, through constriction, the epilarynx physically couples the vocal folds to the supralaryngeal vocal tract. This basic principle is important in explaining a wide range of speech phenomena, such as the mechanism of glottal stop, creaky and harsh (“constricted”) phonation, interaction between vocal fold state and lingual state, and the coordination of phonatory and vowel quality as voice quality, which underlies many register-like patterns. Furthermore, oscillation of the epilarynx and (typically) the vocal folds below is the basis for “growl”, which is demonstrated to have numerous expressions in speech, both phonetically and phonologically. The thesis is explored by detailed examination of three functions of the epilarynx: (1) epilaryngeal vibration, (2) epilaryngeal interaction with the vocal folds, and (3) epilaryngeal interaction with the supralaryngeal vocal tract. Phonetic evaluations of these functions include physiological, theoretical, and taxonomic considerations, imaging data (obtained with laryngeal and lingual ultrasound, simultaneous laryngoscopy and laryngeal ultrasound, and videofluoroscopy), and computational modeling. These phonetic evaluations are then taken as the basis for a model of lower vocal tract phonology. Traditional models of such sounds do not accommodate the epilarynx. Rather than positing new distinctive features, an alternative approach is taken. A theoretical model is proposed which is framed in terms of “phonological potentials”, which are the biases associated with physical principles that underlie the formation of phonological systems and patterns. In the context of epilaryngeal function, the phonological potentials are expressed in terms of synergistic relations amongst gross physiological states that either support or hinder epilaryngeal constriction. These biases are argued to exert an articulation-based typological skewing on phonemic systems and patterning, and numerous cases are examined in support of this claim. Graduate 0290
7

Dynamical modelling of the human larynx in phonation

Apostoli, Adam Graham 2012 (has links)
Producing an accurate model of the human voice has been the goal of researchers for a very long time, but is extremely challenging due to the complexity surrounding the way in which the voice functions. One of the more complicated aspects of modelling the voice is the fluid dynamics of the airflow, by which the process of self-oscillation of the vocal folds is sustained. This airflow also provides the only means by which the ventricular bands (two vocal fold-like structures located a short distance above the vocal folds) are driven into self-oscillation. These have been found to play a significant role in various singing styles and in voice pathologies. This study considers the airflow and flow-structure interaction in an artificial up-scaled model of the human larynx, including self-oscillating vocal folds and fixed ventricular bands. As the majority of any significant fluid-structure interaction takes place between structures found within the larynx, this thesis is limited only to examining this component of the voice organ. Particle Image Velocimetry (PIV) has been used to produce full field measurements of the flow velocity for the jet emerging from the oscillating vocal folds. An important advance in this study is the ability to observe the glottal jet from the point at which it emerges from the vocal folds, thus permitting a more complete view of the overall jet geometry within the laryngeal ventricle than in previous work. Ensemble-averaged PIV results are presented for the experimental model at different phase steps, both with and without ventricular bands, to examine their impact on the dynamics of the human larynx and the glottal jet. Finally, the three-dimensional nature of the glottal jet is considered in order to further understand and test currently held assumptions about this aspect of the jet dynamics. This was achieved by undertaking PIV in a plane perpendicular to that already considered. It is shown that the ventricular bands have an impact on the flow separation point of the glottal jet and on the deflection of the jet centreline. Furthermore, the dynamics of the vocal folds alters when ventricular bands are present, but the glottal jet is found to exhibit similar three-dimensional behaviour whether or not ventricular bands are present.
8

Short and Long Term Effects of the Lee Silverman Voice Treatment(R) in Non-progressive Dysarthria

Rachel Wenke Unknown Date (has links)
No description available.
9

Real-time monitoring of voice characteristics usingaccelerometer and microphone measurements

Virebrand, Marcus 2011 (has links)
VoxLog is a portable voice accumulator, that uses both an accelerometer that measures skin vibrations and a regular microphone to collect data. The goal of the thesis was to implement and evaluate methods that based on this data estimate the three different voice parameters fundamental frequency, phonation and soundpressure level. For pitch, three different methods were evaluated. The different methods all require relatively low computational power since the goal was to implement at least one of them on the digital signal processor in the VoxLog. The results from these evaluations show that the best estimations of pitch were made with a FFT-based approach that uses phase information to get an estimation with high frequencyresolution. Phonation is estimated with an energy based voice activity detection method.This estimation is then used to choose when sound pressure level should be estimated. Here one of the main problems was to make a distinction between when sound pressure level should be estimated for the wearer of the VoxLog or when an estimation should be made for the background noise. This was solved by implementing a time window before and after phonation were neither is estimated. For both pitch and sound pressure level a feedback functionality was implemented. The feedback is given to the user via vibrations in the VoxLog, the feedback is given when estimated parameters break set limits on pitch or sound pressure level.
10

"Influência dos esteróides sexuais sobre a voz falada em mulheres do climatério" Influence of the sexual steroids on the voice speak in women of the climacteric

Janaína Mendes Laureano 8 November 2005 (has links)
São freqüentes as queixas entre as mulheres, particularmente entre as cantoras, de que ocorrem alterações na voz após a menopausa. Há relatos na literatura de que a freqüência fundamental da voz da mulher se altera nesta fase da vida. Como a prega vocal possui receptores para os esteróides sexuais, é possível que essas alterações sejam decorrentes da deficiência estrogênica observada no climatério. O presente trabalho teve como objetivo comparar a freqüência fundamental da voz (F0) de mulheres na pós-menopausa usuárias e não usuárias de terapia de reposição hormonal (TRH) com mulheres no menacme. Foram estudadas 45 pacientes: grupo-controle (15 mulheres de 20 a 40 anos, não usuárias de anticoncepcional hormonal, não fumantes, com ciclos menstruais regulares), grupo com TRH (15 mulheres de 45 a 60 anos, menopausadas há mais de 2 anos, usuárias de valerato de estradiol 1mg/norgestimato 90 mcg há no mínimo 6 meses) e grupo sem TRH (15 mulheres com idade de 45 a 60 anos, menopausadas há mais de 2 anos sem TRH há no mínimo 6 meses). Todas as pacientes foram submetidas à avaliação otorrinolaringológica e videolaringoscopia para confirmar a integridade da laringe. Posteriormente, avaliou-se a F0 com a emissão das vogais “e” e “i” na altura de fala habitual da paciente. A F0 foi analisada através do programa Dr.Speech 3.0®. Foi utilizado o teste ANOVA para comparação das médias de F0 entre os grupos. A média da idade dos grupos controle, com TRH e sem TRH foi respectivamente 30,3 anos, 54,5 anos e 56,5 anos. A média da F0 dos grupos foram respectivamente: vogal “e”: 215,97 Hz; 206,21 Hz e 200,71 Hz, e vogal “i”: 229,89 Hz; 221,79 Hz e 212,79 Hz. Os resultados mostraram uma tendência de agravamento da F0 em menopausadas, sendo a média do grupo com TRH mais próxima do grupo-controle que do grupo sem TRH. Entretanto não houve diferença estatisticamente significativa na F0 da voz para as vogais “e” (p=0,2127) e “i” (p=0,193), comparando os três grupos entre si. De acordo com esses resultados, parece não haver diferença clinicamente relevante na F0 da voz falada entre mulheres no menacme, menopausadas usuárias e não usuárias de TRH. A tendência à diminuição de F0 nas pacientes hipoestrogênicas sugere a possibilidade de que pequenas diferenças, decorrentes da influência hormonal sobre a laringe, que não tenham sido detectadas neste estudo, possam atingir maiores níveis de significância, quando os grupos forem analisados para a voz cantada. The complaints between the women are frequent, particularly between the singers, of whom alterations in the voice occur after the menopause. It has been reported, in literature, that woman’ fundamental frequency is altered in this phase of the life. As the vocal fold possess receivers for the sexual steroids are possible that these alterations are decurrent of the observed hypoestrogenism in the climacteric. To compare the voice fundamental frequency (F0) of postmenopausal women, users and non-users of HRT with women in menache. Forty-five patients have been trialed, divided into the following groups: control group (15 women of 20 to 40 years of age, non-users of hormonal contraceptives, non smokers, with regular menstrual cycles), group with HRT (15 women of 45 to 60 years of age, menopaused for over 2 years, users of estradiol valerate 1mg/norgestimato 90mcg for a minimum period of 6 months) and the group without HRT (15 women of 45 to 60 years of age, menopaused for over 2 years, without HRT for a minimum period of 6 months). All patients had been submitted to the otolaryngological evaluation and videolaryngoscopy in order to confirm the integrity of the larynx. Afterwards F0 has been evaluated by emitting the vowels [e] and [i] in the patient’s habitual voice pitch. The F0 was analyzed using the Dr.Speech Pro. 3 software. The ANOVA test was used in order to compare the averages of F0 between the groups. The average ages of the groups control, with HRT and without HRT were respectively 30,3 years, 54,5 years and 56,5 years. The average F0 of the groups control, with HRT and without HRT were respectively: vowel [e]: 215,97Hz; 206,21Hz and 200,71Hz and vowel [i]: 229,89Hz; 221,79Hz and 212,79Hz. The results showed a trend of aggravation of the F0 in postmenopausal women, once the F0 average of the group with HRT was closer to the group control than the group without HRT. However, in a comparison between those three groups, there were no significant statistical difference in the voice F0 for the vowels [e] (p=0,2127) and [i] (p=0,193). There were no differences in F0, in the speaking voice, between women in menache and postmenopausal users and non-users of HRT. However it’s been recorded a trend in the aggravation of F0 in the postmenopausal women, mainly amongst the without HRT users. In accordance with these results seem not to have significant clinical difference in the F0 of the voice said between women in menacme, postmenopausal users and non-users of HRT. The trend the reduction of F0 in the hypoestrogenism patients suggests the possibility of that small decurrent differences of the hormonal influence on the larynx, that they have not been detected in this study, can reach greaters levels of significance when the groups will be analyzed for the sung voice.

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