The Effect of Superficial Hydration, With or Without Systemic Hydration, on Voice Quality in Future Female Professional Singers

Hypertonic Aerosols Hydrate Airways Longer and Reduce Acidification Risk with Nonpermeating Cation and Permeating Anion Salts

Background: Hyperosmolar aerosols appear to promote or suppress upper airway dysfunction caused by dehydration in a composition-dependent manner. We sought to explore this composition dependence experimentally, in an interventional human clinical study, and theoretically, by numerical analysis of upper airway ion and water transport. Methods: In a double-blinded, placebo-controlled clinical study, phonation threshold pressure (PTP) was measured prenasal and postnasal inhalation of hypertonic aerosols of NaCl, KCl, CaCl2, and MgCl2 in seven human subjects. Numerical analysis of water and solute exchanges in the upper airways following deposition of these same aerosols was performed using a mathematical model previously described in the literature. Results: PTP decreased by 9%-22% relative to baseline (p < 0.05) for all salts within the first 30 minutes postadministration, indicating effective laryngeal hydration. Only MgCl2 reduced PTP beyond 90 minutes (21% below baseline at 2 hours postadministration). By numerical analysis, we determined that, while airway water volume up to 15 minutes postdeposition is dictated by osmolarity, after 30 minutes, divalent cation salts, such as MgCl2, better retain airway surface liquid (ASL) volume by slow paracellular clearance of the divalent cation. Fall of CFTR chloride flux with rise in ASL height, a promoter of airway acidification, appears to be a signature of permeating cation (NaCl) and nonpermeating anion (mannitol) aerosol deposition. For hypertonic aerosols that lack permeating cation and include permeating anion (CaCl2 and MgCl2), this acid-trigger signature does not exist. Conclusions: Nonpermeating cation and permeating anion hypertonic aerosols appear to hydrate upper airways longer and, rather than provoke, may reduce laryngeal dysfunction such as cough and bronchoconstriction.

Mucus Transpiration as the Basis for Chronic Cough and Cough Hypersensitivity

Chronic cough is characterized by a state of cough hypersensitivity. We analyze the process of transpiration, by which water appears to evaporate from laryngeal and tracheal mucus as from the surface of a leaf, as a potential cause of cough hypersensitivity. In this process, osmotic pressure differences form across mucus, pulling water toward the air, and preventing mucus dehydration. Recent research suggests that these osmotic differences grow on encounter with dry and dirty air, amplifying pressure on upper airway epithelia and initiating a cascade of biophysical events that potentially elevate levels of ATP, promote inflammation and acidity, threaten water condensation, and diminish mucus water permeability. Among consequences of this inflammatory cascade is tendency to cough. Studies of isotonic, hypotonic, and hypertonic aerosols targeted to the upper airways give insights to the nature of mucus transpiration and its relationship to a water layer that forms by condensation in the upper airways on exhalation. They also suggest that, while hypertonic NaCl and mannitol may provoke cough and bronchoconstriction, hypertonic salts with permeating anions and non-permeating cations may relieve these same upper respiratory dysfunctions. Understanding of mucus transpiration and its role in cough hypersensitivity can lead to new treatment modalities for chronic cough and other airway dysfunctions promoted by the breathing of dry and dirty air.

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 Vocal Hygiene Treatment Programs for Singers: A Systematic Review

OBJECTIVES

This systematic review aims to explore the effectiveness of voice health education interventions among singers, particularly focusing on vocal hygiene treatment programs tailored for professional voice users.

STUDY DESIGN

Systematic review.

METHODS

Preferred Reporting Items on Systematic Reviews and Meta-Analysis guidelines were followed to conduct this systematic review. Comprehensive searches were conducted in PubMed, Web of Science, Scopus, Science Direct, and Cochrane Library databases. Four articles were selected for detailed review. The studies were evaluated using the Effective Public Health Practice Project tool for quality assessment.

RESULTS

The four reviewed studies primarily utilized the pretest-posttest design to examine the effectiveness of vocal hygiene interventions on singers' vocal health. Two studies investigated the effect of hydration as a treatment method, while the remaining two focused on vocal hygiene instruction. Significant improvements were observed in various vocal health parameters, including maximum phonation time, intensity, Dysphonia Severity Index, and number of daily vocal breaks taken.

CONCLUSION

This systematic review provides valuable insights into the efficacy of vocal hygiene treatment programs for singers. The positive outcomes observed in the reviewed studies underscore the importance of voice health education tailored to singers' specific needs. However, the limited number of eligible studies and the common limitation of small sample sizes highlight the need for further research in this area. Vocal health practitioners, educators, and researchers can utilize the findings of this review to develop evidence-based vocal hygiene interventions that promote the well-being and longevity of singers' vocal performance careers.

Investigation of the Relationship Between Vocal Fatigue, Quality of Life, and Compliance With Vocal Hygiene in Professional Voice Users

PURPOSE

Intensive voice use may lead to the development of voice disorders or voice complaints, such as vocal fatigue, for professional voice users (teachers, academics, call center workers, actors, singers, speech and language therapists, voice trainers, and religious officials). Vocal fatigue has a detrimental effect on occupational, emotional, and social performance, besides the quality of life of the individual. The effect of voice hygiene interventions on voice fatigue is not fully known. The results of studies conducted with different occupational groups are inconsistent. The present study aims to analyze the relationship between vocal fatigue and voice-related quality of life (V-RQOL) in professional voice users, and the impact of vocal hygiene on vocal fatigue.

METHODS

Participants (24 male, 90 female), who were professional voice users without any diagnosis of voice disorders or voice complaints were divided into two groups low vocal hygiene compliance (LVH; n = 66) and high vocal hygiene compliance (HVH; n = 48). In this study, vocal fatigue was measured by the vocal fatigue index (VFI), and V-RQOL was measured by the voice handicap index (VHI-10) and V-RQOL.

RESULTS

VFI subscales (tiredness, avoidance, physical discomfort) have a moderate positive correlation with VHI-10 and V-RQOL, which indicates that there is a significant relationship between vocal fatigue and quality of life amongst professional voice users. While there was no significant difference between the LVH and HVH groups in terms of quality of life, it was found that the vocal fatigue level of the LVH group was higher.

CONCLUSION

This study of professional voice users with healthy voices reveals a relationship between vocal fatigue and V-RQOL. Vocal hygiene compliance may affect professional voice users' vocal fatigue symptoms; the low-compliant group has higher levels of tiredness, avoidance, and physical discomfort. The findings highlight the importance of raising awareness of the problems of professional voice users, even though they have healthy voices and the need for vocal hygiene education programs that target them.

What are the Symptoms that Characterize the Clinical Condition of Vocal Fatigue? A Scoping Review and Meta-Analysis

INTRODUCTION

Vocal fatigue is a clinical manifestation associated with a perception of negative vocal adjustment. It is related to the increase in the sensation of excessive effort when speaking and the lack of conditioning of the muscles and structures that involve vocal production. Because it has a complex and multifactorial diagnosis, there is still no consensus on the symptoms most commonly found in this clinical condition.

OBJECTIVE

To review and analyze the symptoms that characterize the clinical condition of vocal fatigue.

METHODS

This study consists of a scoping review carried out in the Cochrane Library, Embase, Lilacs, and Medline databases. Observational studies or clinical trials from the last 10 years. Studies with participants younger than 18 years of age were excluded; as well as research that did not describe symptoms of vocal fatigue or that presented vocal fatigue as a symptom; studies with patients with neurological, psychiatric, syndromic conditions, or head and neck cancer. The Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies NHLBI-NIH scale was used to assess the methodological quality of selected observational studies and the PEDro scale for the analysis of experimental studies. The steps were performed by three blinded evaluators. Subsequently, meta-analyses of global means were executed for each factor under study; a comparison of the difference in the mean score for each factor between exposed and unexposed; a comparison of the difference in the average score, among non-professional voice users, for each factor between exposed and unexposed.

RESULTS

In the searches performed, 956 articles were found and 29 articles were selected according to the eligibility criteria. Of these, 93.11% of the studies were observational and 6.89% were clinical trials. Regarding the gender and age group of the study samples, women aged between 30 and 45 years were predominant. As for the occupational use of voice, 68.97% of the samples were composed of professional voice users and 31.03% of non-professional voice users, with most professional voice users being teachers and non-professional voice users, individuals with dysphonia or vocal complaint. To assess vocal fatigue symptoms, 28 studies used the Vocal Fatigue Index (VFI) protocol, and only one study used another assessment protocol, Self-Administered Voice Rating. All studies were classified as regular, according to the scale used. As for the meta-analyses performed, the mean scores of the VFI factors were higher among professional voice users when compared to non-professional voice users and higher in dysphonic individuals compared to non-dysphonic individuals.

CONCLUSION

The vocal fatigue symptoms found in this review were common in the populations of professional voice users and non-professional voice users and dysphonic and non-dysphonic individuals. These symptoms were related to vocal recovery after rest, physical discomfort, and restricted vocal use.

Computational Study of the Impact of Dehydration-Induced Vocal Fold Stiffness Changes on Voice Production

OBJECTIVE

Systemic vocal fold dehydration is known to increase vocal fold stiffness, which has been hypothesized to have important effect on voice production. However, it remains unclear whether the dehydration-induced vocal fold stiffness changes can have a noticeable impact on phonation, particularly in normal phonation conditions. The goal of this study was to investigate the impact of vocal fold stiffness changes due to vocal fold systemic dehydration and its significance in daily communication.

METHODS

Parametric computational simulation using a three-dimensional vocal fold model, in which the vocal fold stiffness was varied as a function of systemic dehydration levels based on previously-reported experimental data.

RESULTS

The results showed that systemic dehydration had significant effects on voice production only at high levels of dehydration, at which dehydration increased the phonation threshold pressure and fundamental frequency, and decreased glottal opening area, vocal intensity and glottal efficiency. The effect depended mainly on the overall dehydration level but was also slightly affected by the dehydration distribution and muscular control. However, for dehydration levels typical of normal phonation conditions, the effect was negligible.

CONCLUSIONS

The results indicated that dehydration-induced vocal fold stiffness change likely is not an important mechanism through which vocal fold systemic dehydration affects voice production. Nevertheless, a large decrease in glottal efficiency implies a possible perceived increase of vocal effort under a realistic dehydration condition.

Effectiveness of Thymepearls After Vocal Loading in Professional Voice Users: A Randomized Placebo-Controlled Double-Blind Clinical Trial

OBJECTIVES

Professional voice users depend on their voice for optimal performance of their profession. The aim of this study was to find out to what extent sucking a placebo and thyme represent an improvement of the voice in professional voice users after vocal loading.

METHODS

A randomized placebo-controlled clinical double-blind study was conducted with four measurement moments: a premeasurement, immediately after the vocal loading, after the subsequent ingestion of the "thymepearl" (TP) in the experimental group and in the control group the placebo, and after a half-hour break. Finally, 18 subjects were considered, 9 participants in each group.

RESULTS

No significant differences in the objective measurements of both groups could be observed. However, significant improvements in subjective measures (perceptions of dry mouth and feeling of hoarseness) could be observed after vocal loading by sucking the thymepearls in direct comparison to the placebo.

CONCLUSIONS

Sucking the TP can improve subjective sensation after vocal loading compared with placebo, but no differences are seen on objective vocal measures.

Immediate effect of surface laryngeal hydration associated with tongue trill technique in amateur singers

PURPOSE

To analyze the immediate effect of laryngeal surface hydration associated with the performance of Tongue Trills (TT) on singers.

METHODS

Thirty singers without vocal complaints or laryngeal alterations divided into control (CG) and experimental (EG) groups. The CG performed the TT for five minutes. The EG was submitted a nebulization with 3 ml of saline solution followed by TT for five minutes. Voice self-assessment, acoustic analysis and perceptual assessment were performed at Pre (Pre TT) and post (PTT) moments in CG and pre (Pre TT), post hydration (PH) and post hydration + TT (PHTT) in GE. In the self-assessment were evaluated quality, stability, vocal intensity and hoarseness. There were extract the values of the Fundamental frequency; Jitter%; Shimmer%, Noise-to-harmonic Ratio e Cepstral Peak Prominence-Smoothed (CPPs) in the acoustic analyze. The perceptual evaluation was performed by an experienced speech therapist.

RESULTS

Comparing the results of self-assessment between groups showed improvement in the perception of stability and vocal intensity in the PTT (CG) in relation to PH (EG). Comparison between the EG moments showed a statistical difference in the vocal intensity perception, indicating a better results for PHTT. There was no statistical difference between the groups investigated in the perceptual assessments and acoustic analysis.

CONCLUSION

Surface laryngeal hydration does not potentiate the effect of TT on naturally hydrated singers with 3ml nebulization. For voice professionals with high vocal demand, surface hydration can be introduced during voice use to maintain vocal quality.