A pilot investigation of twang quality using magnetic resonance imaging

Connecting Auditory-Perceptual Prompts Used in Voice Therapy to Anatomy and Physiology: Application to the Estill Voice Model and the Rehabilitation Treatment Specification System

PURPOSE

This clinical tutorial will present the concept of applying auditory-perceptual prompts (implicit instruction) typically used in voice therapy to the anatomy and physiology of the voice production system (explicit instruction) via the Estill Voice Model (EVM) and the Rehabilitation Treatment Specification System (RTSS).

METHODS

EVM offers an integrated implicit-explicit instructional approach to voice training allowing for isolated practice of vocal structures (explicit) that interact to produce functional voice qualities (implicit), such as modal speech and louder projected voice qualities. In EVM, voice quality is correlated with the specific anatomy and physiologic adjustments via 13 Estill Figures and Options (eg, Larynx Figure has three options: High, Mid, and Low). RTSS provides a framework to connect client change in functioning (ie, target) with clinician action (ie, ingredients). Mechanisms of action connect the target to the ingredients by hypothesizing how the treatment is expected to work.

RESULTS

Evidence is provided for connecting auditory-perpetual voice prompts with the anatomy and physiology of voice and supporting an integrated implicit-explicit approach to voice therapy. The concept of linking commonly used implicit auditory-perceptual prompts used in voice therapy (eg, humming, loud "aahh") to explicit anatomy and physiology training (eg, 13 Estill Figures and Options) is demonstrated using EVM and the RTSS framework with case studies and video examples.

CONCLUSIONS

Clinicians may choose to use anatomy and physiology of voice to define and provide explicit instruction for typically used implicit auditory-perceptual prompts. Future research is warranted to test the concept applied to voice therapy models in the literature across prevention and treatment of voice disorders.

Oropharyngeal and Aryepiglottic Narrowing for Twang: A Magnetic Resonance Imaging Study

OBJECTIVE

This study aimed to compare vocal tract configurations between speech and twang qualities.

METHODS

Magnetic resonance imaging data were acquired from five professional vocalists while producing the sustained vowel /i/. Width and area measurements were obtained from the axial (ie, transverse) images to evaluate oropharyngeal narrowing and aryepiglottic (AES) narrowing.

RESULTS

Four out of five participants exhibited a smaller vocal tract area for twang than for speech at the oropharyngeal level, with the extent of narrowing ranging from 18.8% to 49.6%. Only one participant showed a meaningful decrease in oropharyngeal anteroposterior (AP) width, while three participants showed meaningful decreases in oropharyngeal mediolateral (ML) width for twang compared to speech. At the AES level, all participants showed a smaller vocal tract area for twang than for speech, with the extent of narrowing ranging from 11.8% to 52.4%. Two participants exhibited meaningful decreases in AES AP width, while three participants showed meaningful decreases in AES ML width for twang compared to speech.

CONCLUSIONS

Axial imaging revealed oropharyngeal and AES narrowing associated with twang, more prominent in the ML than the AP dimension. Notable individual variations in the mechanism and degree of narrowing at the oropharyngeal and AES levels were observed. The degree of narrowing varied among participants, highlighting the complexity of physiological maneuvers involved in twang production. Future research is necessary to identify broader patterns in twang production for effective pedagogic and therapeutic applications.

Spectral features related to the auditory perception of twang-like voices

BACKGROUND

To the best of our knowledge, studies on the relationship between spectral energy distribution and the degree of perceived twang-like voices are still sparse. Through an auditory-perceptual test we aimed to explore the spectral features that may relate with the auditory-perception of twang-like voices.

METHODS

Ten judges who were blind to the test's tasks and stimuli rated the amount of twang perceived on seventy-six audio samples. The stimuli consisted of twenty voices recorded from eight CCM singers who sustained the vowel [a:] in different pitches, with and without a twang-like voice. Also, forty filtered and sixteen synthesized-manipulated stimuli were included.

RESULTS AND CONCLUSIONS

Based on the intra-rater reliability scores, four judges were identified as suitable to be included in the analyses. Results showed that the frequency of F1 and F2 correlated strongly with the auditory-perception of twang-like voices (0.90 and 0.74, respectively), whereas F3 showed a moderate negative correlation (-0.52). The frequency difference between F1 and F3 showed a strong negative correlation (-0.82). The mean energy between 1-2 kHz and 2-3 kHz correlated moderately (0.51 and 0.42, respectively). The frequency of F4 and F5, and the energy above 3 kHz showed weak correlations. Since the spectral changes under 2 kHz have been associated with the jaw, lips, and tongue adjustments (i.e. vowel articulation) and a higher vertical laryngeal position might affect the frequency of all formants (including F1 and F2), our results suggest that vowel articulation and the laryngeal height may be relevant when performing twang-like voices.

Dark tone quality and vocal tract shaping in soprano song production: Insights from real-time MRI

Tone quality termed "dark" is an aesthetically important property of Western classical voice performance and has been associated with lowered formant frequencies, lowered larynx, and widened pharynx. The present study uses real-time magnetic resonance imaging with synchronous audio recordings to investigate dark tone quality in four professionally trained sopranos with enhanced ecological validity and a relatively complete view of the vocal tract. Findings differ from traditional accounts, indicating that labial narrowing may be the primary driver of dark tone quality across performers, while many other aspects of vocal tract shaping are shown to differ significantly in a performer-specific way.

A Nonrandomized Trial for Student Teachers of an In-Person and Telepractice Global Voice Prevention and Therapy Model With Estill Voice Training Assessed by the VoiceEvalU8 App

Purpose This study investigated the effects of the in-person and telepractice Global Voice Prevention and Therapy Model (GVPTM) treatment conditions and a control condition with vocally healthy student teachers. Method In this single-blinded, nonrandomized trial, 82 participants completed all aspects of the study. Estill Voice Training was used as the stimulability component of the GVPTM to train multiple new voices meeting all the vocal needs of the student teachers. Outcomes were assessed using acoustic, perceptual, and aerodynamic measures captured by the VoiceEvalU8 app at pre and post in fall and during student teaching in spring. Results Significant improvements were achieved for several acoustic and perceptual measures in the treatment conditions, but not in the control condition. The in-person and telepractice conditions produced similar results. The all-voiced phrase and connected speech were more successful in demonstrating voice change for some of the perturbation measures as compared to sustained /a/. Conclusions The treatment conditions were successful in improving the participants' voices for fundamental frequency and some acoustic perturbation measures while maintaining the improvements during student teaching. In addition, the treatment conditions were successful in decreasing the negative impact of voice-related quality of life and vocal fatigue during student teaching. Future research should address the effectiveness of the various components of the GVPTM, the application of the GVPTM with patients with voice disorders, the relevance of defining auditory-perceptual terms by the anatomy and physiology of the voice production system (i.e., Estill Voice Training), and the continued use of the VoiceEvalU8 app for clinical voice investigations. Supplemental Material https://doi.org/10.23641/asha.13626824.

Functional Voice Assessment and Therapy Methods Supported by Telepractice, VoiceEvalU8, and Estill Voice Training

Functional assessment and therapy methods are necessary for a client-centered approach that addresses the client's vocal needs across all environments. The purpose of this article is to present the approach with the intent to encourage discussion and implementation among educators, clinicians, researchers, and students. The functional approach is defined and its importance is described within the context of the World Health Organization's International Classification of Functioning, Disability, and Health with support provided by synchronous and asynchronous telepractice, the VoiceEvalU8 app, server, and web portal, and a framework that defines voice qualities (e.g., resonance, twang, loud, and others) by the anatomy and physiology of the voice production system (i.e., Estill Figures for Voice). Case scenarios are presented to highlight application of the functional voice approach.