Phonation into a glass tube is a voice training and therapy method that leads to beneficial effects in voice production. It has not been known, however, what changes occur in the vocal tract during and after the phonation into a tube. This pilot study examined the vocal tract shape in a female subject before, during, and after phonation into a tube using computer tomography (CT). Three-dimensional finite-element models (FEMs) of the vocal tract were derived from the CT images and used to study changes in vocal tract input impedance. When phonating on vowel [a:] the data showed tightened velopharyngeal closure and enlarged cross-sectional areas of the oropharyngeal and oral cavities during and after the tube-phonation. FEM calculations revealed an increased input inertance of the vocal tract and an increased acoustic energy radiated out of the vocal tract after the tube-phonation. The results indicate that the phonation into a tube causes changes in the vocal tract which remain also when the tube is removed. These effects may help improving voice production in patients and voice professionals.

• MeSH
• akustika řeči MeSH
• analýza metodou konečných prvků MeSH
• biologické modely MeSH
• fonace MeSH
• hlasové řasy fyziologie   radiografie   MeSH
• kvalita hlasu MeSH
• larynx fyziologie   radiografie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• pilotní projekty MeSH
• počítačová rentgenová tomografie MeSH
• rentgenový obraz - interpretace počítačová MeSH
• zobrazování trojrozměrné MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Impact stress (the impact force divided by the contact area of the vocal folds) has been suspected to be the main traumatizing mechanism in voice production, and the main cause of vocal fold nodules. However, there are also other factors, such as the repetitive acceleration and deceleration, which may traumatize the vocal fold tissues. Using an aeroelastic model of voice production, the present study quantifies the acceleration and impact stress values in relation to lung pressure, fundamental frequency (F0) and prephonatory glottal half-width. Both impact stress and acceleration were found to increase with lung pressure. Compared to impact stress, acceleration was less dependent on prephonatory glottal width and, thus, on voice production type. Maximum acceleration values were about 5-10 times greater for high F0 (approx. 400 Hz) compared to low F0 (approx. 100 Hz), whereas maximum impact stress remained nearly unchanged. This suggests that acceleration, i.e. the inertia forces, may present at high F0 a greater load for the vocal folds, and in addition to the collision forces may contribute to the fact that females develop vocal fold nodules and other vocal fold traumas more frequently than males. Copyright 2009 S. Karger AG, Basel.

• MeSH
• akustika řeči MeSH
• biologické modely MeSH
• fonace fyziologie   MeSH
• glottis fyziologie   MeSH
• lidé MeSH
• plíce fyziologie   MeSH
• počítačová simulace MeSH
• pohlavní dimorfismus MeSH
• tlak vzduchu MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Current models of the vocal folds derive their shape from approximate information rather than from exactly measured data. The objective of this study was to obtain detailed measurements on the geometry of human vocal folds and the glottal channel in phonatory position. A non-destructive casting methodology was developed to capture the vocal fold shape from excised human larynges on both medial and superior surfaces. Two female larynges, each in two different phonatory configurations corresponding to low and high fundamental frequency of the vocal fold vibrations, were measured. A coordinate measuring machine was used to digitize the casts yielding 3D computer models of the vocal fold shape. The coronal sections were located in the models, extracted and fitted by piecewise-defined cubic functions allowing a mathematical expression of the 2D shape of the glottal channel. Left-right differences between the cross-sectional shapes of the vocal folds were found in both the larynges.

• MeSH
• biologické modely MeSH
• biomechanika MeSH
• financování organizované MeSH
• glottis anatomie a histologie   fyziologie   MeSH
• hlas fyziologie   MeSH
• hlasové řasy anatomie a histologie   fyziologie   MeSH
• lidé MeSH
• senioři MeSH
• zobrazování trojrozměrné statistika a číselné údaje   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH

• MeSH
• biologické modely MeSH
• fonace fyziologie   MeSH
• hlas MeSH
• hlasové řasy MeSH
• larynx umělý MeSH
• lidé MeSH
• Check Tag
• lidé MeSH

The maximum impact stress at the contact of the vocal folds achieved during the oscillation cycle was estimated in phonation using an aeroelastic model of voice production. Relations of impact stress to the lung pressure, fundamental frequency of self-oscillations, prephonatory glottal width, sound pressure level generated at the end of the glottis and vibration amplitude of the vocal folds were studied. Using the fundamental frequency, prephonatory glottal width, lung pressure and airflow rate values found in normal speech, maximum impact stress values of 2-3 kPa were obtained. The results fall well within the limits reported for excised canine larynges and human subjects. Impact stress increased with lung pressure almost linearly after the phonation threshold but reached a plateau when the limit of maximum glottal opening was reached. When the fundamental frequency and lung pressure were kept constant, impact stress appears to fit closely with a parabolic function of prephonatory glottal half-width.

• MeSH
• financování organizované MeSH
• fonace fyziologie   MeSH
• hlasové řasy patofyziologie   MeSH
• lidé MeSH
• modely anatomické MeSH
• numerická analýza pomocí počítače MeSH
• plicní ventilace fyziologie   MeSH
• počítačová simulace MeSH
• poruchy hlasu patofyziologie   MeSH
• řeč fyziologie   MeSH
• vibrace MeSH
• zvuková spektrografie MeSH
• Check Tag
• lidé MeSH

• MeSH
• analýza metodou konečných prvků * využití   MeSH
• biomechanika MeSH
• fonace * fyziologie   MeSH
• hlasové řasy fyziologie   MeSH
• larynx * fyziologie   MeSH
• lidé MeSH
• mechanické jevy MeSH
• modely anatomické MeSH
• statistika jako téma MeSH
• teoretické modely MeSH
• tvrdé patro fyziologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• práce podpořená grantem MeSH

• MeSH
• analýza metodou konečných prvků * využití   MeSH
• biomechanika MeSH
• biometrie MeSH
• lebka * fyziologie   MeSH
• lidé MeSH
• modely anatomické * MeSH
• modely strukturální MeSH
• počítačová rentgenová tomografie metody   využití   MeSH
• počítačové zpracování obrazu MeSH
• software MeSH
• statistika jako téma MeSH
• teoretické modely MeSH
• vibrace MeSH
• zobrazování trojrozměrné MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

• MeSH
• biomechanika MeSH
• glottis fyziologie   MeSH
• hlas * fyziologie   MeSH
• hlasové řasy * fyziologie   MeSH
• laryngoskopie * metody   využití   MeSH
• lidé MeSH
• mechanické jevy MeSH
• pilotní projekty MeSH
• vibrace MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• práce podpořená grantem MeSH