The Effect of Hydration on the Voice Quality of Future Professional Vocal Performers

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.

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.

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.

Hydration State and Hyaluronidase Treatment Significantly Affect Porcine Vocal Fold Biomechanics

OBJECTIVES

The understanding of vocal fold hydration state, including dehydrated, euhydrated, rehydrated tissue, and how hydration affects vocal fold biomechanical properties is still evolving. Although clinical observations support the benefits of increasing vocal fold hydration after dehydrating events, more mechanistic information on the effects of vocal fold dehydration and the beneficial effects of rehydration are needed. Alterations to hyaluronic acid (HA), an important component of the vocal fold extracellular matrix, are likely to influence the biomechanical properties of vocal folds. In this study, we investigated the influence of hydration state and HA on vocal fold tissue stiffness via biomechanical testing.

STUDY DESIGN

Prospective, ex vivo study design.

METHODS

Fresh porcine vocal folds (N = 18) were examined following sequential immersion in hypertonic (dehydration) and isotonic solutions (rehydration). In a separate experiment, vocal folds were incubated in hyaluronidase (Hyal) to remove HA. Control tissues were not exposed to any challenges. A custom micromechanical system with a microforce sensing probe was used to measure the force-displacement response. Optical strain was calculated, and ultrasound imaging was used to measure tissue cross-sectional area to obtain stress-strain curves.

RESULTS

Significant increases (P ≤ 0.05) were found in tangent moduli between dehydrated and rehydrated vocal folds at strains of ε = 0.15. The tangent moduli of Hyal-digested tissues significantly increased at both ε = 0.15 and 0.3 (P ≤ 0.05).

CONCLUSION

Vocal fold dehydration increased tissue stiffness and rehydration reduced the stiffness. Loss of HA increased vocal fold stiffness, suggesting a potential mechanical role for HA in euhydrated vocal folds.

Analysis of the singing voice handicap index for elderly choristers

PURPOSE

To analyze the singing voice handicap index in elderly choristers and verify its relationship with the profile, habits and health conditions of the participants.

METHODS

110 individuals aged 60 years or older, participating in amateur choirs, were included. Choir singers were interviewed in order to verify data such as age, time in choir singing, vocal classification, and the presence of habits and health conditions adverse to voice production. Subsequently, they answered the questionnaire "Singing Voice Handicap Index (SVHI)", which assesses the individual's self-perception in relation to experiences in the use of the singing voice.

RESULTS

The SVHI score had a median of 25, with a minimum score of 0 and a maximum score of 86. The most scored items were related to physical aspects in the use of singing voice: "I am unable to use my 'high voice'" (Q10) and "My throat is dry when I sing"(Q13). It was found that older adults over 75 years of age had a greater voice handicap when compared to younger ones (p=0.020). Choir singers classified as contralto also had a higher SVHI score (p=0.023), as well as individuals who reported drinking little water (p=0.007).

CONCLUSION

The choristers in this study presented a singing voice handicap index compatible with healthy singing voices. When verifying the relationship of the SVHI score with the characteristics of the participants and with respect to habits and health conditions, it was found that the elderly choir singers over 75 years old, the contralto choir singers, and those who claimed to drink little water had higher scores for the singing voice handicap.

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.

The Effects of Caffeine on Voice: A Systematic Review

BACKGROUND

Caffeine is considered a dehydrating agent due to its diuretic effects and influences the body's fluid balance. The relationship between voice and hydration has been widely investigated and it is accepted that inadequate hydration has detrimental effects on phonation. Since dehydration negatively affects the vocal folds and caffeine is considered a dehydrating agent, it can be hypothesized that voice might be negatively affected by caffeine intake. This systematic review aims to summarize and appraise the available evidence regarding the effects of caffeine on voice.

METHODS

Randomized and non-randomized experimental studies of healthy participants were retrieved following an electronic searching of six databases in June 2020. No publication, language or date restrictions were applied. Data extraction of relevant data and risk of bias assessment was conducted independently by two reviewers.

RESULTS

Five non-randomized experimental studies were deemed eligible for inclusion. The format of the administered interventions in the included studies was either liquid (coffee) or solid (caffeine tablets). Reported outcome measures used to examine the effects of caffeine on phonation consisted of acoustic, aerodynamic and (auditory & self-) perceptual. No measures were adversely affected by caffeine consumption.

CONCLUSION

Clinicians commonly advise patients to refrain from caffeine, as caffeine intake increases diuresis with subsequent effects on fluid balance. Such imbalances can potentially induce dehydration which can be detrimental to phonation. This notion cannot be supported empirically, as the evidence is deemed unreliable and no firm conclusions can be elicited to guide clinical practice. The results of this review demonstrate the lack of research in the field and the necessity for future investigations in order to inform evidence-based practice through reliable and valid outcomes.

Muscle Tension Dysphagia: Contributing Factors and Treatment Efficacy

OBJECTIVE

To determine factors contributing to disease etiology and treatment efficacy.

STUDY DESIGN

Original Report.

SETTING

Tertiary academic center.

METHODS

IRB approved prospective study of 20 patients with reported dysphagia who exhibited normal oropharyngeal and esophageal swallowing function as evidenced by videofluoroscopic swallow study, esophagogastroduodenoscopy, high-resolution esophageal manometry with stationary impedance, and Bravo pH probe off proton pump inhibitor. Patients underwent speech-language pathology intervention.

RESULTS

Atypical laryngeal muscle tension was present in 100% of patients. Forty percent of patients had diagnosed positive gastroesophageal reflux disease. Sixty-five percent of patients showed signs of non-specific laryngeal inflammation and laryngeal hyperresponsiveness during strobolaryngoscopy. All patients reported a mean of 90% recovery by the completion of voice therapy directed toward unloading muscle tension.

CONCLUSION

The study results suggest an association between laryngeal muscle tension and these patients' dysphagia symptoms regardless of associated conditions. Speech-language pathology intervention showed high treatment efficacy.

LEVEL OF EVIDENCE

2c- Outcomes research.

Vocal Hygiene in Collegiate Singers-Does Formal Training Relate to Practices?

BACKGROUND

Vocal hygiene is vitally important for protecting vocal quality and promoting vocal longevity. It includes adequate hydration, avoidance of environmental irritants, and refraining from phonotraumatic behaviors such as screaming, excessive talking, and throat clearing. Formal singing training in addition to enhancing singing techniques, is also assumed to promote good vocal hygiene. Consequently, we investigated whether collegiate singers with formal training are more likely to practice good vocal hygiene habits than untrained collegiate singers.

METHODS

We completed a prospective cohort study, where collegiate singers at Stanford University were voluntarily enrolled in an annual vocal health clinic. Full laryngeal exams were performed and demographic information, formal vocal training status, and information on vocal hygiene habits were obtained through questionnaires. The results were then analyzed by grouping singers as "untrained" if less than 1 year of formal training, and "trained" if greater than a year.

RESULTS

A total of 82 singers were included for analysis, with 49 (59.8%) having greater than one year of formal training. Trained singers were more likely to employ a primary musical singing style of classical or operatic singing compared to untrained singers who were more likely to utilize "R&B" (P < 0.001). No significant differences were found between groups for hydration practices (P = 0.20), caffeine consumption (P = 0.73), warm up practices (P = 0.08), and phonotraumatic behaviors. Alcohol consumption, smoking tobacco, marijuana, e-cigarette usage was similar between groups. Overall, 11% of our sample reported intermittent less than daily marijuana use, with one singer reporting daily consumption. None of the singers in this sample used e-cigarettes. These rates are noticeably lower than the agematched United States population. Perceptions of cigarettes, marijuana, electronic cigarettes, alcohol, and caffeine were also the same between groups, with the vast majority of singers perceiving these agents as harmful to the voice (64%-100% depending on the agent). No laryngeal pathology was identified during laryngeal examination of any singers.

CONCLUSIONS

Vocal hygiene habits are similar between trained and untrained collegiate singers. This likely relates to a desire for vocal longevity irrespective of prior training. This may dispel the long-held assumption that formal training was necessary to develop good vocal habits. We do however, present a very homogenous, highly educated sample of collegiate singers from Stanford University, having significantly less at-risk behavior than their aged-matched counterparts in the general US population. A lack of laryngeal pathology despite extensive vocal demands may also be reflective of good vocal hygiene habits.

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

OBJECTIVE

The aim of this study was to describe the effect of superficial hydration, with or without systemic hydration, on voice quality in future female professional singers by assessing acoustic and perceptual parameters of voice production as well as symptoms of vocal fatigue.

STUDY DESIGN

This is an experimental design study.

METHODS

A study was performed on a sample of 24 female voice majors to ascertain the effect of superficial hydration, with or without systemic hydration, on acoustic parameters and perception of vocal fatigue. The study replicated a prior study by van Wyk et al (2016) with some modifications; we looked at the effect of both systemic and superficial hydration independently and together on voice quality and vocal fatigue. Acoustic measurements including GRBASI, jitter, shimmer, F₀ MPT, frequency min and max, intensity min and max, and dysphonia severity index were measured along with perceived vocal fatigue using the Vocal Fatigue Index.

RESULTS

A statistically significant increase in MPT values were obtained when comparing pre- and post-test results of the hypo hydrated (P = 0.015) and superficial hydration condition (P = 0.004). A significant increase in frequency min (Hz) within the hypo hydrated condition was also observed (P = 0.019). A significant increase was observed in the intensity min (dB) (P = 0.010) and F₀ min (Hz) (P = 0.002) within the combined hydration condition. Also, when superficial hydration was applied, mean shimmer % (P = 0.016), MPT (sec) (P = 0.003) and dysphonia severity index (P = 0.020) scores increased significantly in a between-group, post-test comparison. A significant reduction in mean intensity max (dB) (P = 0.049) and intensity min (dB) (P = 0.018) was also observed.

CONCLUSIONS

This study demonstrates that the use of superficial hydration results in positive outcomes of perceptual parameters of voice quality and symptoms of vocal fatigue in future female professional singers. However, mixed results were observed regarding the acoustic parameters of voice. The superficial hydration data is compelling enough to warrant implementing in a vocal hygiene protocol for singers.

Effects of Humidification of the Vocal Tract and Respiratory Muscle Training in Women With Voice Symptoms-A Pilot Study

OBJECTIVE

The aim of this study was to determine the efficacy of a 4-week breathing exercise intervention in participants with voice symptoms.

METHODS

Six nonsmoking women (mean age 49) experiencing voice symptoms used a novel device WellO₂ for respiratory exercises that provides counter pressure during both inspiration and expiration and warms and humidifies the breathing air. Speech samples were acoustically (Acoustic Voice Quality Index) and perceptually (grade, roughness, breathiness, asthenia, and strain scale) analyzed, and perceived voice symptoms and self-reported effort in breathing and phonation were obtained. Respiratory measurements included breathing frequency and pattern, peak expiratory flow, forced vital capacity, and forced expiratory volume in 1 minute.

RESULTS

The total scores of Acoustic Voice Quality Index and some of its subcomponents (shimmer and harmonic-to-noise ratio), and the grade, roughness, and strain of the GRBAS scale indicated significantly improved voice quality. However, neither the nature or frequency of the experienced voice symptoms nor the perceived phonatory effort changed as the function of intervention. According to the participants, their breathing was significantly less effortful after the intervention, although no significant changes were observed in the objective respiratory measurements with a spirometer.

CONCLUSION

Training with the WellO₂ device has the potential to improve voice quality. The combination of inspiratory and expiratory training and warmed, humidified air is a multifaceted entity influencing several parts in the physiology of voice production. The effects of using WellO₂ need to be confirmed by further studies with a larger number of participants.

Vocal Health Practices Among School Teachers: A Study From Chennai, India

INTRODUCTION

A healthy vocal system is a prerequisite to produce a serviceable voice for any vocal profession. The concept of vocal health (VH) among teachers is worth exploring considering their known risk of developing voice disorders.

AIM

To provide socioculture-specific information on VH practices and nature of voice problems in teachers.

METHOD

A VH questionnaire was developed to elicit opinions toward one's own voice health and factors that indicated and contributed to impaired/poor VH from 384 school teachers.

RESULTS AND DISCUSSION

'Flexible voice' (23%), 'enduring voice' (22%), and 'good voice' (22%) were descriptions to indicate good VH by teachers. 'Vocal fatigue' (13%), 'dry throat' (9.4%), 'throat irritation' (4.7%), and 'pain while swallowing/speaking' (3.1%) were frequently reported throat sensations to indicate poor VH. For 30.2% of the teachers, voice mattered for professional needs. However, most of them managed to cope with voice problems through several home remedies and 'intentional/self-imposed neglect' despite their vocal difficulties. Sociocultural factors influencing these findings and scope to escalate voice problems in teachers as a public health issue are discussed.

CONCLUSION AND IMPLICATION

Insight and perception of VH based on self-reports and information on voice practices among teachers pertinent to this geographical location provide scope to develop models for counseling and preventive treatment for voice problems.

Acoustic and Perceived Measurements Certifying Tango as Voice Treatment Method

Voice disorders are affecting everyday life in many levels, and their prevalence has been studied extensively in certain and general populations. Notably, several factors have a cohesive influence on voice disorders and voice characteristics. Several studies report that health and environmental and psychological etiologies can serve as risk factors for voice disorders. Many diagnostic protocols, in the literature, evaluate voice and its parameters leading to direct or indirect treatment intervention. This study was designed to examine the effect of tango on adult acoustic voice parameters. Fifty-two adults (26 male and 26 female) were recruited and divided into four subgroups (male dancers, female dancers, male nondancers, and female nondancers). The participants were asked to answer two questionnaires (Voice Handicap Index and Voice Evaluation Form), and their voices were recorded before and after the tango dance session. Moreover, water consumption was investigated. The study's results indicated that the voices' acoustic characteristics were different between tango dancers and the control group. The beneficial results are far from prominent as they prove that tango dance can serve stand-alone as voice therapy without the need for hydration. Also, more research is imperative to be conducted on a longitudinal basis to obtain a more accurate result on the required time for the proposed therapy.

Dysphonia in adults with developmental stuttering: A descriptive study

BACKGROUND

Persons with stuttering (PWS) often present with other co-occurring conditions. The World Health Organization's (WHO) International Classification of Functioning, Disability and Health (ICF) proposes that it is important to understand the full burden of a health condition. A few studies have explored voice problems among PWS, and the characteristics of voices of PWS are relatively unknown. The importance of conducting future research has been emphasised.

OBJECTIVES

This study aimed to describe the vocal characteristics of PWS.

METHOD

Acoustic and perceptual data were collected during a comprehensive voice assessment. The severity of stuttering was also determined. Correlations between the stuttering severity instrument (SSI) and the acoustic measurements were evaluated to determine the significance. Twenty participants were tested for this study.

RESULT

Only two participants (10%) obtained a positive Dysphonia Severity Index (DSI) score of 1.6 or higher, indicating that no dysphonia was present, while 90% of participants (n = 18) scored lower than 1.6, indicating that those participants presented with dysphonia. Some participants presented with weakness (asthenia) of voice (35%), while 65% presented with a slightly strained voice quality. Moderately positive correlations between breathiness and SSI (r = 0.40, p = 0.08) have been reported. In addition, participants with high SSI scores also scored a poor DSI of below 1.6, as observed by a moderate positive correlation between SSI and DSI (r = 0.41).

CONCLUSION

The majority of PWS presented with dysphonia, evident in the perceptual or acoustic parameters of their voices. These results can be used for further investigation to create awareness and to establish intervention strategies for voice disorders among PWS.