Acoustic, Aerodynamic, Morphometric, and Perceptual Changes During and After Semi-Occluded Vocal Tract Exercise: An Integrative Review

A Human-Centered Design Approach to SOVTE Straw Phonation Instruction

OBJECTIVES

Extensive research has demonstrated that straw/tube phonation exercises produce positive effects on the voice quality of the user. The purpose of this study was to explore pedagogical practices employed by a range of voice professionals when using SOVTEs by applying human-centered design approaches to examine workflow and communication between teachers and students.

METHOD/DESIGN

The researchers conducted a series of five participatory role-playing workshop activities at a multi-disciplinary vocology conference that included speech-language pathologists, voice scientists, physicians, singing teachers, acting voice teachers, choral directors, and singers. Volunteers were asked to assume the role of teaching or learning straw phonation exercises. The other participants from each workshop were asked to provide written and verbal feedback regarding the teacher/student dynamics and what they found most important and relevant in terms of best practices for SOVTEs. Expert evaluators subsequently provided similar feedback based on video recordings of the workshops.

RESULTS

While there was variability noted in teaching techniques and results, common themes emerged in the analysis. Successful and unsuccessful student and teacher techniques were identified by the workshop participants. Through the video analysis, the research team identified themes in instructional teaching, experiential learning, and straw articulation and mechanics.

CONCLUSIONS

The benefits of straw/tube phonation exercises on voice quality have been well-established and are clear. As we continue to refine best practices in SOVTEs and, in particular, straw phonation, involvement of experts in HCD as part of multidisciplinary teams may lead to the eventual design of SOVTE tools that provide greater precision, consistency, and effectiveness both in clinical and pedagogical settings, and aid in the differentiation of SOVTE approaches within the taxonomy of vocal habilitation and rehabilitation techniques.

Optimizing Diameter, Length, and Water Immersion in Flow Resistant Tube Vocalization

OBJECTIVE

The objective was to quantify the range of airflow resistance and oral pressure attainable with variation of length, diameter, and water immersion depth of tubes and straws.

STUDY DESIGN

Pressure-flow equations for tubes, determined previously for variable tube geometries, were used to calculate oral pressure ranges. Human subjects were then recruited to use the variable tube geometries to produce oral pressures, which were quantified with commercial manometers.

RESULTS

Nomograms for airflow resistances and oral pressures are plotted as a function of tube length, tube diameter, and water insertion depth.

CONCLUSIONS

It is shown that tube diameters in the range of 2.5-3.0 mm with tube lengths of 10-40 cm produce oral pressures in the range of 10-40 cm H2O. Insertion of the distal end into water adds a pressure in the amount of the depth of insertion. Maximum power transfer with different tube geometries is discussed.

The Effect of Phonation into a Glass Tube Immersed in Water Compared to Other Interventions on General Degree of Vocal Deviation, Fundamental Frequency, Sound Pressure Level, and Vocal Self-assessment in Vocally Healthy Individuals: A Systematic Review and Meta-analysis

OBJECTIVE

To analyze the effect of phonation in a glass tube immersed in water compared to other interventions on general degree of vocal deviation, fundamental frequency, sound pressure level, and vocal self-assessment in vocally healthy individuals.

METHODS

This is a systematic review and meta-analysis developed from the research question: "In vocally healthy individuals, what is the effect of phonation into a glass tube immersed in water versus other vocal interventions, other activities, or no intervention on general degree of vocal deviation, fundamental frequency, sound pressure level, and vocal self-assessment?" An electronic search was performed using Medline, LILACS, Cochrane Library, Embase, Web of Science, and SCOPUS databases, and a manual search was performed in the gray literature (Brazilian Digital Library of Theses and Dissertations and OpenGrey), the Journal of Voice, and the citations of the studies. Studies with (P) population of adults with healthy voices, (I) intervention with phonation into a glass tube immersed in water, (C) comparison with other vocal interventions, other activities, or no intervention, (O) outcomes of the general degree of vocal deviation, fundamental frequency, sound pressure level, and vocal self-assessment, and an (S) study with the experimental or quasi-experimental design were included. Risk of bias assessment and meta-analysis of the outcomes were performed.

RESULTS

A total of 457 studies were found in the search; four were selected for the systematic review and meta-analysis. In the risk of bias assessment, there was an uncertain risk of selection and performance bias in 100% of the studies and uncertain risk of detection bias of 75%. All studies had an experimental design, and most of them were conducted on women. In the fundamental frequency analysis, there was no difference between the effect sizes of the interventions (z = 0.471, P = 0.638). In the vocal self-assessment, the estimated odds ratio was 1.31, showing a greater chance of improvement in the intervention group than with the comparison group (z = 3.45, P < 0.001). There were not enough studies to analyze the general degree of vocal deviation and sound pressure level outcomes.

CONCLUSION

Phonation into a glass tube immersed in water has a greater positive effect on vocal self-assessment than other interventions in vocally healthy individuals.