Sensitivity analysis of muscle mechanics-based voice simulator to determine gender-specific speech characteristics

A Semiautomated Protocol Towards Quantifying Vocal Effort in Relation to Vocal Performance During a Vocal Loading Task

To increase the reliability and comparability of vocal loading studies, this paper proposes the use of a standardized approach with experiments that are [1] grounded on consistent definitions of terms related to vocal fatigue (vocal effort, vocal demand, and vocal demand response), and [2] designed to reduce uncertainty and increase repeatability. In the approach, a semi-automated vocal loading task that also increases efficiencies in collecting and preparing vocal samples for analysis was used to answer the following research question: To what extent is vocal effort and vocal demand response sensitive to changes in vocal demands (ie, noise only, noise plus duration)? Results indicate that the proposed protocol design consistently induced change in both vocal effort and vocal demand response, indicating vocal fatigue. The efficacy of future vocal loading studies would be improved by adopting a more consistent methodology for quantifying vocal fatigue, thus increasing interstudy comparability of results and conclusions.

Relationship Between Tasked Vocal Effort Levels and Measures of Vocal Intensity

Purpose Patients with voice problems commonly report increased vocal effort, regardless of the underlying pathophysiology. Previous studies investigating vocal effort and voice production have used a range of methods to quantify vocal effort. The goals of the current study were to use the Borg CR100 effort scale to (a) demonstrate the relation between vocal intensity or vocal level (dB) and tasked vocal effort goals and (b) investigate the repeated measure reliability of vocal level at tasked effort level goals. Method Three types of speech (automatic, read, and structured spontaneous) were elicited at four vocal effort level goals on the Borg CR100 scale (2, 13, 25, and 50) from 20 participants (10 females and 10 males). Results Participants' vocal level reliably changed approximately 5 dB between the elicited effort level goals; this difference was statistically significant and repeatable. Biological females produced a voice with consistently less intensity for a vocal effort level goal compared to biological males. Conclusions The results indicate the utility of the Borg CR100 in tracking effort in voice production that is repeatable with respect to vocal level (dB). Future research will investigate other metrics of voice production with the goal of understanding the mechanisms underlying vocal effort and the external environmental influences on the perception of vocal effort.

Intraglottal Pressure: A Comparison Between Male and Female Larynxes

Acoustic differences in the phonated sounds made by men and women are related to laryngeal and vocal tract structural differences. This model-based study explored how typical vocal fold differences between males and females affect intraglottal pressure distributions under conditions of different glottal angles and transglottal pressures, and thus how they may affect phonation. The computational code ANSYS Fluent 6.3 was used to obtain the pressure distributions and other aerodynamic parameters for laminar, incompressible flow. Typical values of the vocal fold length, the vertical glottal duct length, and the lateral vocal fold tissue depth were selected both for males and females under conditions of nine typical convergent/divergent glottal angles and three transglottal pressures. There was no coupling of the upstream or downstream vocal tracts, and also no vocal fold contact in these two-dimensional static glottal geometries. Results suggest that males tend to have greater intraglottal pressures for the convergent glottal shape that occurs during glottal opening, and the male glottis offers less flow resistance than the female glottis. These results suggest that the male vocal folds may vibrate more easily (ie, with lower transglottal pressure) but the tissue differences may nullify such an hypothesis. Also, the peak velocities in the glottis were dependent on the transglottal pressure driving the flow and the minimal glottal diameter, which were the same for both the male and female larynxes, rather than on the inferior-superior length of the glottis or the anterior-posterior glottal length. In addition, the tangential forces for larger glottal convergent angles was significantly greater in the female larynx. The entrance loss coefficients, however, were similar between the male and female larynxes, except for the uniform glottis for which the values were larger for the male larynx. The results suggest that the structural differences between male and female vocal folds should be well specified when building computational and physical models of the larynx.