Modelling study of the physical background for voice therapy with tubes

0490467 - ÚT 2019 RIV FI eng A - Abstract
Horáček, Jaromír - Radolf, Vojtěch - Laukkanen, A. M.
Modelling study of the physical background for voice therapy with tubes.
29th Congress of Union of the European Phoniatricians. Helsinki: University of Helsinki, 2018 - (Geneid, A.). s. 1-230
[Congress of Union of the European Phoniatricians /29./. 13.06.2018-16.06.2018, Helsinky]
R&D Projects: GA ČR(CZ) GA16-01246S
Institutional support: RVO:61388998
Keywords : biomechanics of voice * voice therapy * computer modelling
OECD category: Acoustics

Phonation into a tube with the distal end in air or submerged in water (water resistance therapy) is used for voice therapy. This study explores the effective mechanisms of tube therapy using a computer model and a physical model consisting of silicone vocal folds and a plexiglas vocal tract. First formant frequency F1 decreased by 71% and F2 by 19% for phonation into a glass resonance tube (length 27 cm, inner diameter 7.8 mm) with the distal end in air, compared to the production of [u:]. F1 descended slightly above F0. For the tube in water, F1 decreased by 92%, reaching ca 28 Hz where the water bubbling frequency (19–24 Hz) was just below F1. The bubbling frequency occurs close to the acoustic–mechanical resonance of the vocal tract. This resonance helps F1 to descend lower –close to F0 in speech, which can further enhance the water voice therapy effect. Loops of subglottic pressure versus glottal area variation in time clearly differentiate vowel phonation from both therapy methods. In both therapy methods, part of the airflow energy required for phonation is substituted by the acoustic energy utilizing the first acoustic resonance. Thus, less flow energy is needed for vibration of the vocal folds, which means improved vocal economy. The effect can be stronger in water resistance therapy if the water bubbling frequency nears the acoustic–mechanical resonance of the vocal tract and simultaneously the fundamental frequency approaches the first formant frequency.

Permanent Link: http://hdl.handle.net/11104/0286931