This thesis examined the effects of combination inhaled corticosteroids (ICs) on the stability of six aerodynamic measures of phonation utilizing a traditional benchtop model with leporine larynges. The motivation for this study was based on the increase of voice disorders associated with IC use in recent years. The aerodynamic measures examined were phonation threshold pressure (PTP), phonation threshold flow (PTF), onset resistance, sustained pressure, sustained flow, and sustained resistance. Leporine larynges were selected as the model for this study due to histological similarities between leporine and human vocal folds that make them ideal for translational research. Rabbits were either exposed to saline solution or ICs for 8 weeks before being sacrificed. After being sacrificed, larynges were excised and dissected. After dissection, the larynges were mounted on a benchtop, the aerodynamic data were gathered, and stability over multiple phonation trials was calculated. The results indicate that the variation between individual rabbits across the measures did not differ significantly. However, after controlling for trial, the average variation of the groups across all trials did differ significantly. PTP and sustained pressure were more variable for the inhaler group, while PTF, sustained flow, onset resistance, and sustained resistance were more variable for the control group. These results suggest that some level of variability in aerodynamic measures both within and between subjects is to be expected when using the leporine benchtop model. Furthermore, while IC exposure does not seem to impact within-subject variability, it does influence between-subjects variability.

Combination corticosteroid inhalers are the primary treatment option for long-term pulmonary disorders including asthma, persistent bronchitis, and chronic obstructive pulmonary disease. Common side effects of these medications are xerostomia in the mouth and throat, hoarseness, and soreness in the oropharynx. Research indicates that a large percentage of the inhaler particles are deposited onto laryngeal tissue, leaving an alteration of laryngeal mucosal properties. As the first stage in a long-term project, this thesis addresses the need for baseline phonatory data that will lay groundwork for quantifying inhaler-induced phonatory changes. Excised larynx research is a powerful tool for assessing aerodynamic alterations that accompany laryngeal pathology. Porcine (pig) larynges are a traditional species employed in voice disorder research, though leporine (rabbit) larynges are an emerging species that lends itself to histologic vocal fold studies as they have the most similar vocal fold cover structure to humans compared to any other animal to date. The purpose of this study was to examine the measurement stability of six aerodynamic parameters in a traditional excised larynx benchtop model. Specifically, the current author assessed measurement stability of leporine larynges compared to porcine larynges with the following aerodynamic metrics: phonation onset pressure (PTP; cmH2O), phonation onset flow (PTF; L/m), sustained pressure (cmH2O), sustained flow (L/m), onset laryngeal resistance (cmH2O/L/m), and sustained laryngeal resistance (cmH2O/L/m). A total of 30 larynges—15 leporine and 15 porcine—were mounted on a benchtop setup; phonation was sampled over 15 trials for each larynx. Measurement stability for the above six tokens was examined using coefficient of variation (%) analyses. Leporine larynges demonstrated significantly less variation across all six aerodynamic parameters when compared to porcine larynges. The leporine PTP values were most stable as compared to leporine and porcine pressure and airflow values. Leporine airflow values were also more stable than porcine PTP and PTF values. These results indicate that leporine larynges might be a preferred excised larynx specimen for certain benchtop phonation studies. These findings are important for establishing expected measurement variability in porcine and leporine larynges, particularly when translating benchtop research to laryngeal pathology.

Subglottic stenosis (SGS) is a narrowing of the airway below the vocal folds and above the trachea. This narrowing may be idiopathic or caused by scarring in the airway due to prolonged endotracheal intubation, radiation therapy, trauma, or gastroesophageal reflux disease. People who present with SGS often experience respiratory difficulty both at rest and during exertion. Breathing difficulty increases with stenosis severity. SGS is also associated with voice problems. Research has identified relationships among stenosis severity, voice function and certain types of surgical management; however, many aspects of these relationships are not fully understood due to the complexities of studying human phonation in this population. The purpose of the present study was to examine the effects of SGS on aerodynamic features of voice function using an excised larynx benchtop mechanical model. Specifically, this research involved the comparison of excised porcine vocal fold vibration at baseline and under experimental conditions of 50% and 75% stenosed. The dependent variable was phonation threshold pressure (PTP), the minimum pressure needed to initiate and maintain vocal fold vibration. PTP was analyzed for nine excised porcine larynges, sampled three times each, at baseline and the two stenosis conditions. The results of this study revealed no differences in PTP based on within-subjects comparisons. Because airflow changes with airway narrowing, this finding might indicate that other factors are responsible for the voice problems associated with SGS that were not accounted for in the current mechanical model. Vocal fold tone is not easily simulated in a benchtop setup and might be an important consideration for future studies. The quantification and manipulation of vocal fold adduction, as well as the study of high-speed imaging, could be useful in future work involving excised larynx mechanical models for the study of SGS. The results from this pilot work represent an important step toward optimizing the experimental setup for studying aerodynamic features of SGS.

The purpose of this study was to examine external laryngeal oscillation and its potential effects on phonation threshold pressure (PTP; cm H2O) and phonation threshold flow (PTF; L/sec). Measures of PTP and PTF have inherent limitations due to the nonlinear nature of phonation, influencing their clinical and experimental utility. This is true particularly for tracking relatively small changes in voice function because variability in the measure itself can be larger than that resulting from voice change. Elevated PTP and PTF are associated with a variety of voice disorders and correlate with self-reported vocal effort and fatigue. Prior studies involving silicone and excised animal larynges have demonstrated PTP reduction in response to external oscillation. In an extension of this work, this thesis examined external laryngeal oscillation and aerodynamic voice measures in two experiments including a translational benchtop to human approach. Experiment 1 used a within-subjects counterbalanced design to examine PTF in 12 porcine larynges. Larynges were fitted with a custom oscillation device and 30 phonation trials were conducted for each larynx, 15 with external oscillation and 15 without. Although summary statistics indicated that PTF was lower with external oscillation, differences were not significant. Experiment 2 applied a within-subjects counterbalanced design to examine PTP in four healthy adult females and one healthy adult male. Individuals produced repeated syllable strings of /pi/ productions at comfortable pitch with and without external oscillation using an electrolarynx and the second and third syllables were averaged. Descriptive analysis indicated that PTP was lowered for female participants but not the male participant. Taken together, the results of these studies offer preliminary evidence that external oscillation influences voice onset aerodynamic measures. The effects of external oscillation seem to be more evident in PTP. These findings have important clinical and research applications for PTP measurement and the potential positive influence on voice function. These preliminary results indicate the need for further research in this area.

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.

The current study examined the effects of three speech conditions (voiced, whispered, mouthed) on articulatory kinematics at the sentence and word level. Participants included 20 adults (10 males, 10 females) with no history of speech, language, or hearing disorders. Participants read aloud six target utterances in the three different speaking conditions while articulatory kinematics were measured using the NDI Wave electromagnetic articulograph. The following articulators were examined: mid tongue, front of tongue, jaw, lower lip, and upper lip. One of the target utterances was chosen for analysis (It's time to shop for two new suits) at the sentence level and then further segmented for more detailed analysis of the word time. Results revealed a number of significant changes between the voiced and mouthed conditions for all articulators at the sentence level. Significant increases in sentence duration, articulatory stroke count, and stroke duration as well as significant decreases in peak stroke speed, stroke distance, and hull volume were found in the mouthed condition at the sentence level when compared to the voiced condition. Peak velocity significantly decreased in the mouthed condition at the word level, but overall the sentence level measures were more sensitive to change. These findings suggest that both laryngeal activation and auditory feedback may be necessary in the production of normally articulate speech, and that the absence of these may account for the significant changes between the voiced and mouthed conditions.

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.

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.

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

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