The impact of phonation mode and vocal technique on vocal fold closure in young females with normal voice quality

Immediate and Short-term Effects of Straw Phonation in Air or Water on Vocal Fold Vibration and Supraglottic Activity of Adult Patients with Voice Disorders Visualized with Strobovideolaryngoscopy: A Pilot Study

Purpose The first purpose of this study was to investigate and compare the short-term effects after a semi-occluded vocal tract (SOVT) therapy session consisting of straw phonation (SP) in air or water on vocal fold vibration and supraglottic activity of adult patients with voice disorders, visualized with strobovideolaryngoscopy (SVL). The second purpose of this study was to investigate and compare immediate changes in the patients' vocal fold vibration and supraglottic activity during SP in air or water, visualized with SVL. Methods Twelve adult patients with voice disorders (eight women and four men, mean age 52 years) were assigned randomly to one of two study groups: SP in air or SP in water. Immediately before and after a therapy session of 15 min, participants underwent a rigid SVL to determine the short-term effects of the SP session. At the posttherapy examination, flexible SVL while performing SP was added to determine the effects occurring during SP. The visual-perceptual ratings were performed blindly and in random order by three laryngologists, using the Voice-Vibratory Assessment with Laryngeal Imaging rating form for stroboscopy. ResultsShort-term effects after SP: After the SP-in-air session, the supraglottic mediolateral compression decreased significantly. The SP-in-water session led to significantly increased left vibrational amplitude. Immediate effects during SP: During SP in air, a significantly increased left amplitude and mucosal wave, and significantly decreased mediolateral supraglottic activity, were found. SP in water tended to decrease the vibrational amplitude during performance of the task. A trend toward higher anteroposterior supraglottic compression was observed during both SP in air and water, being more prominent in the latter. Conclusion SP in air led to less false vocal fold adduction and consequently less hyperfunction. The small increment in anteroposterior supraglottic activity during SP in air and water might be related to epilarynx narrowing, an economic phenomenon associated with SOVT exercises. The effects on vibrational amplitude were rather ambiguous. The small reduction in amplitude during SP in water is expected to diminish vocal fold impact stress and therefore creates an ideal basis for voice therapy. The increment in amplitude and mucosal wave during SP in air might indicate insufficient supraglottic pressure to obtain the favorable effects of semi-occlusion. Whether or not the rise in amplitude after the SP-in-water session is due to voice efficiency or voice fatigue remains unknown. Future larger-scale investigation in subgroups of voice patients is needed to explore these hypotheses.

Towards Automated Vocal Mode Classification in Healthy Singing Voice-An XGBoost Decision Tree-Based Machine Learning Classifier

Auditory-perceptual assessment is widely used in clinical and pedagogical practice for speech and singing voice, yet several studies have shown poor intra- and inter-rater reliability in both clinical and singing voice contexts. Recent advances in artificial intelligence and machine learning offer models for automated classification and have demonstrated discriminatory power in both pathological and healthy voice. This study develops and tests an XGBoost decision tree based machine learning classifier to develop automated vocal mode classification in healthy singing voice. Classification models trained on mel-frequency cepstrum coefficients, MFCC-Zero-Time Windowing, glottal features, voice quality features, and α-ratios demonstrated 92% average F1-score accuracy in distinguishing metallic and non-metallic singing for male singers and 87% average F1-score for female singers. The model distinguished vocal modes with 70% and 69% average F1-score for male and female samples, respectively. Model performance was compared to human auditory-perceptual assessments of 64 corresponding samples performed by 41 professional singers. The model performed with approximating or subpar performance to human assessors on task-matched problems. The XGBoost gains observed across tested features reveal that the most important attributes for the tested classification problems were MFCCs and α-ratios between high and low frequency energy, with models trained on only these features achieving performance not statistically significantly different from the best tested models. The best automated models in this study do not yet match human auditory-perceptual discrimination but improve on previously reported F1-average accuracies in automated classification in singing voice.

Immediate effects of straw phonation in air or water on the laryngeal function and configuration of female speech-language pathology students visualised with strobovideolaryngoscopy: A randomised controlled trial

BACKGROUND

A promising way to obtain vocal economy and efficiency is by semi-occluding the vocal tract while phonating. Current knowledge about the immediate effects of semi-occluded vocal tract (SOVT) phonation on the laryngeal function and configuration is based mainly on computer modelling or excised larynges studies. In in vivo SOVT studies, electroglottography (EGG) has been the most commonly used laryngeal outcome, showing contradictory results between studies. Therefore, exploring these aspects by direct visualisation of the human larynx during SOVT phonation using strobovideolaryngoscopy (SVL) is needed.

AIMS

The aim of this study was to investigate and compare the immediate effects of straw phonation (SP) in air, SP in 2 cm water, and SP in 5 cm water (with stirring straws), on the laryngeal function and configuration of a homogeneous group of vocally healthy female speech-language pathology students, visualised with flexible SVL.

METHODS & PROCEDURE

A randomised controlled trial was used. Fifty-two female speech-language pathology students (mean age: 18.7 years, SD: 0.6) were assigned randomly to one of three experimental groups or a control group: (1) SP in air, (2) SP in 2 cm water, (3) SP in 5 cm water or (4) [u] phonation with similar soft onset and slightly pursed lips as in SP but without a straw (control group). The participants underwent flexible SVL during habitual [u] phonation, followed by the specific SOVT exercise of their group assignment. All video samples were evaluated randomly and blindly by two experienced investigators using the Voice-Vibratory Assessment with Laryngeal Imaging (VALI) rating form, first independently and then by consensus.

OUTCOME & RESULTS

Compared to habitual phonation, the vibrational amplitude decreased during SP in 5 cm water and SP in 2 cm water, being more prominent in the first, more flow-resistant exercise. The mucosal wave also decreased during SP in 5 cm water. The anteroposterior (AP) supraglottic compression similarly increased during SP in air, SP in 2 cm water, and SP in 5 cm water. Further, a rise in mediolateral (ML) compression and a decrease in phase symmetry and regularity were found during SP in 2 cm water. A similar decrease in regularity was observed during SP in 5 cm water.

CONCLUSIONS & IMPLICATIONS

Both SP in air and SP in water cause positive immediate laryngeal effects for voice training opportunities. More AP supraglottic activity found during each SP exercise might indicate epilarynx narrowing, an economic phenomenon associated with SOVT. Immersing the straw in water additionally diminished the vibrational amplitude, lowering vocal fold impact stress and risk for phonotrauma during the exercise. The decreased regularity of the vibrational cycles during SP in water might be due to the varying back pressure created by the water bubbling. The impact of SP in water on ML supraglottic compression needs further investigation.

WHAT THIS PAPER ADDS

What is already known on the subject A promising way to obtain vocal economy and efficiency is by semi-occluding the vocal tract while phonating. Current knowledge about the immediate effects of semi-occluded vocal tract (SOVT) phonation on the laryngeal function and configuration is based mainly on computer modelling or excised larynges studies. In in vivo SOVT studies, electroglottography (EGG) has been the most commonly used laryngeal outcome, showing contradictory results between studies. Therefore, exploring these aspects by direct visualisation of the human larynx during SOVT phonation using strobovideolaryngoscopy (SVL) is needed. What this paper adds to existing knowledge Group results of the current study generally support earlier computer modelling and in vivo studies, strengthening the current SOVT knowledge. Both SP in air and SP in water cause positive immediate laryngeal effects for voice training opportunities. More anteroposterior (AP) supraglottic activity found during each SP exercise might indicate epilarynx narrowing, an economic phenomenon associated with SOVT. Immersing the straw in water additionally diminished the vibrational amplitude, lowering vocal fold impact stress and risk for phonotrauma during the exercise. The decreased regularity of the vibrational cycles during SP in water might be due to the varying back pressure created by the water bubbling. The impact of SP in water on ML supraglottic compression needs further investigation. What are the potential or actual clinical implications of this work? Current results support that both SP in air and SP in water can be useful exercises in voice training. SP in water has shown the additional gain of lowering the vibrational amplitude during the exercise, hence supporting its appropriateness for vocal warm-ups by minimising vocal fold impact stress and the risk of phonotrauma. In the future, large-scale randomised controlled trials in other subgroups of voice users, including dysphonic patients, are needed to support evidence-based practice. SVL can facilitate the search for individualised training and therapy approaches.

Glottal Closure in Women with No Voice Complaints or Laryngeal Disorders

Introduction  The understanding of normal vocal production is essential to guide any voice professional as it is fundamental to understand the effects of the posterior glottal gap on the vocal quality. Objective  The aim of the present study was to verify the association between glottic closure, acoustic parameters, and some characteristics of the videolaryngostroboscopy of young women without vocal complaints nor laryngeal disorders. Methods  This is a cross-sectional study with 56 women between 20 and 30 years old who underwent videolaryngostroboscopy. The acoustic parameters of the vowel /a:/ were analyzed using the Praat software, Release 4.6.10 (Paul Boersman and David Weenik, Amsterdam, Netherlands). Statistical Analysis  The chi-squared, Fischer, and Kruskall-Wallis tests were applied, with 5% significance. Results  Significant occurrence of posterior glottal gap (85.71%, p  < 0.001), of normal vocal folds vibration amplitude (82.14%, p  < 0.001), and of absence of significant constriction of the laryngeal vestibule (98.21%, p  < 0.001); no significant association of the glottic closure with the vocal acoustic parameters; no significant association of glottic closure, vocal folds vibration amplitude, and constriction of the laryngeal vestibule. Conclusion  There was a predominance of posterior glottal gap, normal vocal folds vibration amplitude, and absence of laryngeal vestibule constriction, and no relation with the acoustic parameters, suggesting that the posterior glottal gap did not generate impact on the vocal production of the young adult women studied.

Short-Term Effect of Two Semi-Occluded Vocal Tract Training Programs on the Vocal Quality of Future Occupational Voice Users: "Resonant Voice Training Using Nasal Consonants" Versus "Straw Phonation"

PURPOSE

The purpose of this study was to determine the short-term effect of 2 semi-occluded vocal tract training programs, "resonant voice training using nasal consonants" versus "straw phonation," on the vocal quality of vocally healthy future occupational voice users.

METHOD

A multigroup pretest-posttest randomized control group design was used. Thirty healthy speech-language pathology students with a mean age of 19 years (range: 17-22 years) were randomly assigned into a resonant voice training group (practicing resonant exercises across 6 weeks, n = 10), a straw phonation group (practicing straw phonation across 6 weeks, n = 10), or a control group (receiving no voice training, n = 10). A voice assessment protocol consisting of both subjective (questionnaire, participant's self-report, auditory-perceptual evaluation) and objective (maximum performance task, aerodynamic assessment, voice range profile, acoustic analysis, acoustic voice quality index, dysphonia severity index) measurements and determinations was used to evaluate the participants' voice pre- and posttraining. Groups were compared over time using linear mixed models and generalized linear mixed models. Within-group effects of time were determined using post hoc pairwise comparisons.

RESULTS

No significant time × group interactions were found for any of the outcome measures, indicating no differences in evolution over time among the 3 groups. Within-group effects of time showed a significant improvement in dysphonia severity index in the resonant voice training group, and a significant improvement in the intensity range in the straw phonation group.

CONCLUSIONS

Results suggest that the semi-occluded vocal tract training programs using resonant voice training and straw phonation may have a positive impact on the vocal quality and vocal capacities of future occupational voice users. The resonant voice training caused an improved dysphonia severity index, and the straw phonation training caused an expansion of the intensity range in this population.