Article

Phonation threshold pressure measurement with a semi-occluded vocal tract.

National Center for Voice and Speech, The Denver Center for the Performing Arts, Denver, CO, USA.
Journal of Speech Language and Hearing Research (Impact Factor: 1.93). 09/2009; 52(4):1062-72. DOI: 10.1044/1092-4388(2009/08-0110)
Source: PubMed

ABSTRACT The purpose of this article was to determine if a semi-occluded vocal tract could be used to measure phonation threshold pressure. This is in contrast to the shutter technique, where an alternation between a fully occluded tract and an unoccluded tract is used.
Five male and 5 female volunteers phonated through a thin straw held between the lips. Oral pressure behind the lips was measured. Mathematical predictions of phonation threshold pressures were compared to the measured ones over a range of frequencies.
It was shown that, for a 2.5-mm diameter straw, phonation threshold pressures were obtainable over a 2-octave range of fundamental frequency by all volunteers. In magnitude, the pressures agreed with the 0.2-0.5 kPa values obtained in previous investigations. Sensitivity to viscoelastic and geometric properties of the vocal folds was generally not compromised with greater oral impedance, but some differences were predicted theoretically in contrast to an open mouth configuration.
Because phonation threshold pressure is always dependent on vocal tract interaction, it may be advantageous to choose an exact and fixed oral semi-occlusion for the measurement and interpret the results in light of the known acoustic load.

3 Followers
 · 
180 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of this study was to describe changes in aerodynamic and electroglottographic (EGG) measures immediately after completing three semi-occluded vocal tract (SOVT) exercises.
    Journal of voice: official journal of the Voice Foundation 09/2014; 29(2). DOI:10.1016/j.jvoice.2014.05.009 · 0.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This contribution is aimed to provide material that can be used to develop more realistic physical models of voice production. The experimental methodology and the results of measurement of subglottal, oral (substitute for subglottic) and acoustic air pressure (captured at a distance of 20 cm in front of the subject's mouth) are presented. The data were measured during ordinary speech production and when the acoustic impedance and mean supraglottal resistance were raised by phonating into differently sized tubes in the air and having the other end submerged under water. The results presented in time and frequency domain show the physiological ranges and limits of the measured pressures in humans for normal and extreme phonation. Keywords: Biomechanics of voice, measurement of oral pressure, voice exercises, phonation into tubes.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objectives. To investigate the immediate effects of humming and subsequent um-hum phonation on the computed parameters of electroglottographic (EGG) signals in muscle tension dysphonia (MTD) patients and nondysphonic speakers. Methods. We included 21 MTD participants exhibiting both vocal roughness and supraglottic compression, who were able to produce successful humming and um-hum phonation. Twenty nondysphonic participants were selected as controls. Each participant was instructed to perform three phonatory tasks: natural phonation, humming phonation without pitch changes, and subsequent um-hum phonation, that is, humming with a pitch glide up as if agreeing with someone. Acoustic and EGG signals were recorded while the participants performed these tasks. Computed parameters reflecting the irregularities invocal fold vibrations and the degree of glottal contact were calculated and compared between the tasks. Results. The MTD group showed decreases in both perceptual vocal roughness and acoustic perturbation parameters while performing the tasks. The perturbation parameters of EGG signals and the standard deviation of the contact quotient (CQ) also exhibited significant decreases associated with either of humming or um-hum phonation in both groups. In addition, the CQ exhibited significant increases following humming alone in the MTD group and the combination of humming and um-hum phonation in both groups. Conclusions. These results suggest that the combination of humming without pitch changes and subsequent um-hum phonation have the immediate effect in adjusting the regularity of vocal fold vibration and augmenting the degree of glottal contact in MTD patients as well as nondysphonic speakers, whereas humming alone increases the degree of glottal contact in MTD patients.
    Journal of voice: official journal of the Voice Foundation 06/2014; 28(6). DOI:10.1016/j.jvoice.2014.02.004 · 0.94 Impact Factor