Immediate Effect of Semioccluded Vocal Tract Exercises Using Resonance Tube Phonation in Water on Women Without Vocal Complaints

Comparative Study of Two Semi-Occluded Vocal Tract Protocols: A Randomized Clinical Trial

INTRODUCTION

Semi-occluded vocal tract exercises (SOVTEs) are widely used as a therapeutic tool to create flow resistance in the upper airway. The current study was a randomized controlled clinical trial to establish the efficacy of two SOVTE protocols, flow-resistant tube (FRT) and Lessac-Madsen Resonant Voice Therapy (LMRVT). Exploratory investigations included a noninferiority analysis of FRT to the widely adopted therapy protocol (LMRVT), as well as examining the dosing required to improve acoustic measures and subjective ratings.

METHOD

Sixty-seven participants with voice disorder were randomized into one of five groups: 4-week FRT (n = 14), 8-week FRT (n = 19), 4-week LMRVT (n = 15), 8-week LMRVT (n = 5), and control (n = 14). Voice Handicap Index (VHI) and Vocal Fatigue Index scores were collected pre- and posttreatment. Acoustic analysis using the Acoustic Voice Quality Index was completed. We compared VHI between controls and 8-week FRT and LMRVT, adjusting for pre-VHI using linear regression. We examined the efficacy of 4-week protocols relative to controls and conducted a noninferiority comparison of FRT (4 and 8 weeks) to LMRVT (4 and 8 weeks) using 5- and 10-point margins. Finally, we compared the 4- versus 8-week sessions for both therapies.

RESULTS

A statistically significant reduction of VHI in both 8-week FRT relative to controls (-10.60, 95% CI [-19.80, -1.40], p = .025) and 8-week LMRVT (-15.74, 95% CI [-29.40, -2.08], p = .025) was found. We also found an improvement in 4-week FRT relative to controls (-10.11, 95% CI [-20.03, -0.20], p = .046), but the 4-week LMRVT result was not statistically significant (p = .057). FRT was found to be noninferior to LMRVT in terms of VHI using a 10-point margin (FRT - LMRVT: 0.69, 95% CI [-5.76, 7.15], p = .01), but not using a 5-point margin (p = .054). There were no statistically significant differences in VHI scores between 4- and 8-week sessions for either therapy.

CONCLUSIONS

Both FRT and LMRVT improved VHI scores relative to controls. FRT was noninferior to LMRVT in terms of VHI scores. There were no statistically significant differences in VHI scores between 4- and 8-week therapy sessions.

Vocal Training in Healthy Individuals: A Scoping Review

OBJECTIVE

This study aimed to map the characteristics and effects of vocal training approaches in individuals with healthy voice.

METHODS

This is a scoping review based on three research questions: What are the interventions used for vocal training of individuals with healthy voice? What are their prescription parameters? What are their effects? The search was conducted electronically in the databases of Embase, Lilacs, Medline, Scopus, and Web of Science. The study selection was based on the reading of titles, abstracts, and full text, applying the eligibility criteria. Data related to the characteristics of the publication, sample, and intervention were extracted. Measures/outcomes and results were also extracted. Quantitative synthesis was performed, and the results were presented in descriptive format.

RESULTS

In total, 221 studies were identified during the search, of which 23 were selected. The most frequently used approach in the vocal training of individuals with healthy voice was the Semi-Occluded Vocal Tract Exercise (SOVTE), mainly with tube and straw phonation. Many studies have focused on the immediate effect, with varying dosages. The main outcome measures were acoustic analysis, aerodynamic evaluation, electroglotography, and vocal self-assessment. Positive effects were mainly observed on aerodynamic and acoustic parameters. Only one study reported negative results in the self-assessment.

CONCLUSION

The SOVTE is most frequently performed to provide an immediate effect in the acoustic analysis and has also demonstrated positive effects on vocal self-assessment. Medium and long-term effects and dosages are rarely reported and should be also investigated.

Is There an Ideal Performance Time for the Latex Tube Exercise?

PURPOSE

SOVTE has been widely used in voice clinic. Estimates of time to perform the technique with a flexible latex tube are still unknown. This study aimed to investigate the immediate effect of flexible latex tube immersed in water on amateur singers after 1, 3, 5 and 7 minutes, considering: (a) the singers' self-assessment regarding voice and vocal effort; (b) acoustic parameters; and (c) auditory-perceptual parameters of voice quality.

METHODS

Twenty nine amateur singers (14 women and 15 men) performed the exercise with latex tube (35 cm X 0.9 cm) in one 1-minute set and three 2-minute sets. Data collection was conducted before and immediately after each set using sustained emission of vowel [a].

RESULTS

Women and men were considered separately. Vocal self-assessment showed a statistically significant increase in negative sensations after 7 minutes of exercise for women. Auditory-perceptual analysis indicated voices were perceived more often as "equal" comparing pre exercise with first minute set and more often as "better" in the third and fifth minutes comparing with pre exercise only for women. The other parameters showed no significance.

CONCLUSIONS

The exercise with flexible latex tube in amateur singers promoted improvement in vocal quality after 3 and 5 minutes for women. Also, the women presented significant negative sensations after 7 minutes. Immediate effect on the analyzed parameters was not observed in men.

Effectiveness of Semi-Occluded Vocal Tract Exercises (SOVTEs) in Patients with Dysphonia: A Systematic Review and Meta-Analysis

BACKGROUND

Dysphonia is a disorder characterized by an alteration in the overall quality of the voice which reduces quality of life. Therefore, we assessed the effectiveness of SOVTEs in the management of dysfunctional and organic dysphonia for acoustic, perceptual-auditive, aerodynamic parameters and self-perception of the disease.

METHODS

a systematic review and meta-analysis were conducted. Findings were reported according to the PRISMA statement. Five databases were searched for RCTs and non- or quasi-RCTs. Studies were independently assessed using the Cochrane Risk of bias (RoB) and ROBINS-I tools. Effect sizes (ES) were calculated only at post-treatment. GRADE criteria were used to assess the quality of evidence.

RESULTS

eight articles were included. Studies investigated several SOVTEs, alone or in combination. None of the study was completely judged at low RoB. The quality of evidence resulted very low for each analysis. SOVTEs revealed to be statistically more effective than control interventions in improving F0 (ES: -14.42; CI 95%: -27.16, -1.69); P = 0.03), whereas shimmer did not change significantly (ES: -0.43; CI 95%:-02.02, 1.15; P = 0.59). Not significant changes in favor of control groups were found for jitter (ES: 0.13; CI 95%: -0.14, 0.40; P  = 0.34) and overall gravity in the perceptual-auditory evaluation (ES: 0.13 CI 95%: -0.50, 0.77; P = 0. 68). Among secondary outcomes, evidence suggested that SOVTEs are more effective than control interventions in Psub reduction (ES: -1.47; CI 95%: -2.84, -0.10; P = 0.03); self-assessment resulted not significantly in favor of SOVTEs (VHI/VRQoL: ES -0.23; CI 95% -1.14, 0.69; P = 0.63 and VTDS/VDSI: ES -4.85, CI 95% -25.13, 15.42; P = 0.64).

CONCLUSION

results obtained showed that voice therapy based on SOVTEs is not to consider significantly superior if compared to other treatments, even if a favorable trend was detected and should be taken into consideration. Further high-quality RCTs on specific SOVTEs are recommended to produce better-quality evidence.

Volitional and Non-volitional Devices Used in Voice Therapy and Training: A Scoping Review-Part A

OBJECTIVE

To map the volitional and non-volitional devices used by speech and language pathologists (SLPs) in voice training and therapy and characterize their use in research on voice interventions.

METHODS

This scoping review is the first part of a larger study. The electronic search was carried out by mapping the references in PubMed/Medline, LILACS/BVS, Scopus, Web of Science, EMBASE, and the Cochrane Library, and the manual search was carried out in the grey literature. Two blind independent reviewers selected and extracted data; divergences were solved by consensus. The data extracted in this part of the study were the authorship and year of publication, country, study design, sample characteristics, intervention modality, ingredient, target, mechanism of action, dosage, and outcome measures. They were addressed with descriptive analysis.

RESULTS

Publications that use devices as ingredients are mostly from the last two decades, mainly carried out in the United States of America and Brazil, in adults of both sexes with behavioral dysphonia. Forty-two types of devices were used, many of them with similar approaches but different nomenclatures. Most devices were used voluntarily, focusing on vocal function, and aiming to increase source and filter interaction. Most studies used silicone tubes. The most reported technical specification to apply the ingredient was surface electrodes on the neck. Device dosage was time-controlled, and the most used outcomes were self-assessment and acoustic analysis.

CONCLUSION

Devices are currently used as ingredients in vocal interventions, with a greater focus on increasing the source and filter interaction, associated with silicone tubes (the most used devices in these studies), which have been dosed with performance time. Outcomes were measured with self-assessment instruments.

The Role of the Vocal Tract's Acousto-Mechanical Resonance on the Mechanism of Bubble Release From Tubes Used in SOVTE

AND OBJECTIVES

Semi-occluded vocal tract exercises involving a tube with a distal end immersed in water have been used as a voice rehabilitation technique for nearly 60 years. Advantages of this technique include a constant flow resistance, which is mainly dependent on the tube's immersion depth, and an oscillatory component of the back pressure due to bubble release, which is assumed to provide relief of muscle hypertension around the laryngeal and pharyngeal regions. The goal of this study is twofold. First, to shed more light on the contribution of geometrical parameters, such as tube inner diameter and inclination, on the amplitude of the back pressure oscillation and on the bubble release frequency (BRF). The second goal aims to understand the role of vocal tract compliance on the mechanism of bubble release. We hypothesize that the low-frequency acousto-mechanical resonance of a real compliant vocal tract becomes strongly coupled with the mechanism of bubble release, thereby augmenting the back pressure oscillation and dictating the BRF.

METHODS

The BRF and the back pressure are assessed experimentally as a function of flow rate for tubes with a non-compliant upstream condition, considering different diameters and inclinations. These results are compared with theoretical predictions and the experimental data obtained with six adult subjects, from which the vocal tract acousto-mechanical resonance frequencies are also assessed.

RESULTS

The results obtained with tubes involving a non-compliant upstream condition agreed well with the theoretical results and did not indicate a significant influence of the inclination nor the inner diameter on the BRF and on the oscillatory component of the back pressure. Despite the good agreement with the theory, the results obtained from the tube with a non-compliant upstream termination diverged significantly from those obtained with human subjects. In the latter case, the back pressure fluctuation was considerably higher and the BRF measured for each subject coincided with the frequency associated their respective vocal tract acousto-mechanical resonance.

CONCLUSIONS

Results indicate that the BRF is essentially driven by the acousto-mechanical resonance of the vocal tract. Furthermore, the substantial increase on the amplitude of the oscillatory component of the back pressure suggests a strong feedback loop between the source of pressure (bubble release mechanism) and the resonator (vocal tract). The high-pressure fluctuations within the oral cavity implies that subjects need a considerable extra effort to adjust their vocal tract in order to achieve an adequate impedance match between vocal folds and vocal tractsd to produce voice.

Recognition of the Effect of Vocal Exercises by Fuzzy Triangular Naive Bayes, a Machine Learning Classifier: A Preliminary Analysis

OBJECTIVES

Machine learning (ML) methods allow the development of expert systems for pattern recognition and predictive analysis of intervention outcomes. It has been used in Voice Sciences, mainly to discriminate between healthy and dysphonic voices. Parameter patterns of vocal acoustic analysis and vocal perceptual assessment can be evaluated by ML classifiers, such as the Fuzzy Triangular Naive Bayes (FTriangNB), after using techniques that improve the vocal quality of individuals with healthy or dysphonic voices. Thus, the goal of this study was to analyze the performance of the FTriangNB to detect patterns in the acoustic parameters and the auditory-perceptual assessment of 12 women with dysphonia and 12 vocally healthy women, after performing three vocal exercises (tongue trills, semi-occluded vocal tract exercise with a high-resistance straw - SOVTE, and over-articulation).

METHODS

The FTriangNB classifier contained in the Fuzzy Class package was implemented in the data analysis software R Studio version 1.4.1106 for Macintosh. The confusion matrix was extracted, as well as the accuracy, the Kappa coefficient, and the class statistics. The final result was compared with those generated by FTriangNB with the same variables from the preapplication database of the exercises.

RESULTS

The FTriangNB presented good accuracy (87.5%) and Kappa coefficient (81.3%), and showed almost perfect agreement after application of the exercises, while the results before the application of the exercises demonstrated accuracy without acceptable discrimination capacity (33.3%) and Kappa coefficient with a poor agreement (-6.67%). The Semioccluded Vocal Tract Exercises (SOVTE) with high strength straw presented with a sensitivity and Negative Predictive Value (NPV) of value 1 (one), and the over-articulation's specificity and Positive Predictive Value (PPV) also showed a value of 1 (one).

CONCLUSIONS

The FTriangNB showed great accuracy in recognizing the effect of vocal exercises. Exploratory studies with larger samples using FTriangNB, as well as other Machine Learning classifiers should be further carried out for this purpose in the Voice Science to enable inferences.

The Immediate and Long-Term Effects of Tube and Mask+Tube Phonation in Water Exercises and Their Duration as Measured by Electroglottographic and Nasometric Parameters

OBJECTIVE

This study investigated the immediate effects and their persistence (at 15 minutes) of various durations of semi-occluded vocal tract exercise (SOVTE) (standard tube into water and modified mask+tube into water exercises) as measured by electroglottographic (EGG) and nasometric parameters.

METHODS

The study included 30 women aged 19 through 28 years with healthy voices, and it comprised five randomly implemented procedures (Ps): P1-tube phonation into water for 5 minutes; P2-tube phonation into water for 10 minutes; P3-tube+ventilation mask phonation into water for 5 minutes; P4-tube+ventilation mask phonation into water for 10 minutes; P5-phonation with ventilation mask for 5 minutes. Fifteen-minute voice rest breaks were provided between each procedure. Nasometric and electroglottographic measurements were taken before, during, immediately after and at 5, 10, and 15 minutes after the exercises, and the recorded measurements were analyzed.

RESULTS

The immediate effects of P3 and P4 on voice quality showed better performance than the other procedures. Among all the procedures, P1 had the smallest effect on voice quality in terms of nasometric and EGG parameters and the least degree of effect permanence. In all the fluctuating SOVTE procedures except P1, the nasalance scores decreased (P1, P2, P3, and P4: fluctuating SOVTE; P5: steady SOVTE).

CONCLUSION

The tube phonation exercises modified by the addition of a ventilation mask were highly advantageous in terms of EGG parameters. In addition to this, regardless of the mode of application of the retention time, it was observed that the positive effect (ie, lower vertical laryngeal position) of the exercises applied for 10 minutes was higher than the exercises applied for 5 minutes.

Mapping of the Execution of Resonance Tubes Phonation Immersed in Water Exercise in Adults: A Scoping Review

OBJECTIVE

To map the execution of resonance tubes phonation immersed in water exercise in adults with healthy or altered voices.

METHODS

This study was a scoping review. An electronic search was performed using the following databases: MEDLINE, LILACS, SCOPUS, Web of Science, EMBASE, Cochrane Library, gray literature, and a manual search. A blinded review was performed by two authors to determine the selection and extraction procedures. Studies with adult participants with dysphonic or healthy voices who underwent intervention with phonation in a resonance tube immersed in water in the context of the vocal clinic, with an experimental intervention, quasi-experimental, or before and after the intervention were included. Data from the publication, sample, execution, and results obtained from the exercises were extracted by two blinded reviewers. Disagreements were resolved through consensus. The analysis was performed quantitatively.

RESULTS

A total of 44 publications were analyzed. Among these, Brazilian studies were the most frequent, with a publication peak in 2020. The characterization of the sample was variable, with a higher frequency of participants of both sexes who were not voice professionals. The most frequent studies were before and after exercise with a resonance tube immersed in water, in one session, with an exercise execution time of 3 minutes; in cases of more than one series of executions, the 30-sseconds rest time was more frequent. The most used resonance tube was a flexible silicone tube, with a wall thickness of 0.1 mm, immersion container in a 500-, 510-, or 600-mL bottle, 2/3 filled with water, and the resonance tube immersed 2 cm from the water surface. The most used phonatory task was flow phonation with rounded lips similar to the articulation of the vowel /u/. Acoustic analysis and vocal self-assessment are the most commonly used outcome measures. The best results were obtained in the self-assessment.

CONCLUSION

There is significant variability in the information on the execution of resonance tubes phonation immersed in water exercise influenced by vocal diagnosis and experience with previous vocal training. Studies on the effects of this exercise have been concentrated over the last decade and are of the vocal training and therapy. Acoustic and self-assessment measures were used to verify the results, with self-assessment being the outcome that most frequently indicated positive results.