The inability to produce soft voice (IPSV): a tool to detect vocal change in school-teachers

Special Education Teachers' Self-Assessed Voice Health Regarding Voice Use Habits

OBJECTIVES

Special education teachers (SETs) work with students with disabilities. To get and keep these students' attention during the lesson, they may use their voices with high loudness and frequent pitch changes. These situations can be tiring for their voices and affect their vocal health. This study aimed to compare SETs' voice fatigue, reflux symptoms, and self-assessments according to their voice use habits in their work and social lives.

METHODS

A total of 208 SETs were included. A Teacher Voice Use Habits Questionnaire was developed by considering the literature, taking expert opinion, and conducting a pilot study. In addition, the Vocal Fatigue Index (VFI), Voice Handicap Index-30 (VHI-30), and Reflux Symptom Index (RSI) were used. One-way ANOVA, Mann-Whitney U, Kruskal Wallis-H, and Pearson correlation analyses were performed.

RESULTS

Of SETs, 37.5% reported frequent hoarseness, and 65.4% reported voice fatigue during/at the end of the day. Those who answered "yes" to the questions about talking loudly at home, having the television on at home, feeling stressed in the work environment, eating and drinking before going to bed at night, smoking, having frequent colds, talking loudly during the day, and voice fatigue during/at the end of the day had significantly higher scores in all scales. Those who used their voice for more than 6hours were found to have significantly higher scores on the VFI and RSI. In all scales, the scores of those who made very frequent long phone calls were significantly higher.

CONCLUSION

According to the SETs' reports, it was concluded that they did not comply with the rules of vocal hygiene, although they used their voices for a long time. This situation should be considered an occupational health problem in schools, and it may be helpful to screen this group's voice disorders and design preventive programs.

Can Resident Auditory-Perceptual Voice Assessments Predict Medical Urgency of Voice Disorders?

BACKGROUND/OBJECTIVES

Growing reliance on telemedicine has created new triaging challenges. This study investigated how effectively otolaryngology resident auditory-perceptual voice assessments performed via telemedicine determined the need for urgent in-person clinic visits.

METHODS

Twelve otolaryngology resident physicians (PGY1-PGY5) performed auditory-perceptual assessments on 25 voice samples recorded during initial voice evaluations. Voice samples were balanced in severity and taken in equal numbers from patients with the following diagnoses: benign laryngeal lesions, laryngeal cancer, functional voice disorders, laryngeal edema (associated with LPR), and laryngeal paralysis/paresis. Urgent diagnoses were defined as laryngeal cancer and severe unilateral laryngeal paralysis. For each voice sample, residents were initially blinded to patient medical history. Residents rated severity of voice disorder, predicted patient diagnosis, and determined the urgency of seeing the patient in clinic. Residents then reviewed information from the patient's medical history and again rated urgency of voice disorder.

RESULTS

On average, residents identified urgent voice disorders in 56% of cases. After reviewing medical history, this number significantly increased to 77% (P = 0.001). Voice severity, smoking history, time since onset, and course of symptoms were considered most influential when determining medical urgency of voice patients. Year in residency program had no effect on rating accuracy. As expected, diagnostic accuracy of auditory-perceptual assessments was low, ranging from 40% for laryngeal paralysis/paresis to 5% for laryngeal edema.

CONCLUSION

Auditory-perceptual voice assessment, combined with medical history, predicted most medically urgent voice disorders. Further work should investigate if task-specific training might improve these results and which medical history items are most critical. Until accuracy of auditory-perceptual assessment of medical urgency is improved, these data underscore the importance of laryngeal examination in identifying medical urgency and etiology of dysphonia.

The Effects of Room Acoustics on Self-reported Vocal Fatigue: A Systematic Review

PURPOSE

The main objective of the present systematic review is to quantify the relationship between the room acoustics and self-reported vocal fatigue.

METHODS

A comprehensive literature search and systematic review were conducted using PubMed/MEDLINE, Science Direct, Web of Science, EBSCO, and Scopus databases. Two inclusion criteria were defined: (1) description of a relationship between the room acoustics and self-reported vocal fatigue; and (2) reporting of raw data and/or a statistic of the association between the variables. Risk of bias in the included studies was assessed via the Quality Assessment Tool for Quantitative Studies Effective Public Health Practice Project. The occurrences and frequencies of the most common parameters in the literature are presented, and a quantitative summary of their relationships is reported.

RESULTS

In total, 12 publications met the inclusion criteria. The most relevant measures of self-reported vocal fatigue were the Vocal Fatigue Index (n = 3), Vocal Signs and Symptoms Questionnaire (n = 1), and vocal fatigue visual analog scales (n = 2). The most relevant room acoustic parameters include noise conditions (n = 6) and reverberation time (n = 2). The relationships between the room acoustic parameters and self-reported vocal fatigue are quantified and reported while maintaining the concepts stated in the original articles and outlining their similarities.

CONCLUSION

Overall, background noise and reverberation time were determined to be the most significant independent variables associated with self-reported vocal fatigue. A primary limitation of the evidence was inconsistent measures of self-reported vocal fatigue.

Systematic Review of Literature on Prevalence of Vocal Fatigue Among Teachers

BACKGROUND

Previous results suggest that teaching is a high-risk profession for developing voice disorders.

OBJECTIVE

This study aims to determine the prevalence of vocal fatigue among teachers and its relationship with voice acoustic parameters reported in previous studies.

METHOD

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement Guidelines, we performed a systematic literature review including five databases: Scopus, Scielo, ScienceDirect, PubMed, and Web of Science. Information on study population, definition and evaluation of vocal fatigue, and teaching characteristics were extracted from each paper. The quality of the included publications was assessed using the "Quality assessment tool for quantitative studies".

RESULTS

In total, 14 publications met the inclusion criteria. The two most common work-related factors of vocal fatigue were high levels of noise inside classrooms and loud speaking voice use. Some investigations reported voice acoustic parameters such as fundamental frequency and vocal Sound Pressure Levels as associated with vocal fatigue.

CONCLUSION

Vocal fatigue is a prevalent symptom among teachers associated with teaching vocal demands. However, studies on objective parameters that complement self-reports, to quantify vocal fatigue are needed to determine permissible values for healthy occupational voice use.

Mitigating the Effects of Acute Vocal Exertion in Individuals With Vocal Fatigue

OBJECTIVES/HYPOTHESIS

To investigate the effects of acute vocal exertion on individuals with vocal fatigue and to determine whether semi-occluded vocal tract exercises (SOVTEs) are more effective than vocal rest in mitigating acute effects.

STUDY DESIGN

Prospective, repeated-measures design.

METHODS

On consecutive days, 10 individuals (6 males, 4 females) with scores indicating vocal fatigue on the Vocal Fatigue Index completed two 10-minute vocal exertion tasks. Vocal rest or SOVTEs were interspersed in counterbalanced order between exertion tasks. Respiratory kinematic, acoustic, aerodynamic, and self-perceptual measures were collected at baseline, following vocal exertion, following SOVTE/vocal rest, and following the second exertion task.

RESULTS

Acute vocal exertion worsened phonation threshold pressure (P < .001) and vocal effort (P < .001) and reduced maximum fundamental frequency (P < .001). Speech was terminated at lower lung volumes following vocal exertion (decreased lung volume termination [LVT], P < .001). Exertion-induced changes in vocal effort and LVT were significantly reversed by both vocal rest and SOVTE. Detrimental changes in voice measures reoccurred following the second vocal exertion task. SOVTE and vocal rest protected against changes in respiratory kinematics when vocal exertion was resumed.

CONCLUSIONS

Vocal exertion impacted laryngeal, respiratory, and self-perceptual measures in individuals with vocal fatigue. Both SOVTE and vocal rest partially mitigated changes in voice measures and prompted more efficient respiratory strategies that were maintained when vocal exertion resumed. These data increase our understanding of how individuals with vocal fatigue respond to vocal exertion tasks and offer preliminary guidance for optimal clinical recommendations.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:2732-2739, 2021.

Psychometric Analysis of an Ecological Vocal Effort Scale in Individuals With and Without Vocal Hyperfunction During Activities of Daily Living

Objective The purpose of this study was to examine the psychometric properties of an ecological vocal effort scale linked to a voicing task. Method Thirty-eight patients with nodules, 18 patients with muscle tension dysphonia, and 45 vocally healthy control individuals participated in a week of ambulatory voice monitoring. A global vocal status question was asked hourly throughout the day. Participants produced a vowel-consonant-vowel syllable string and rated the vocal effort needed to produce the task on a visual analog scale. Test-retest reliability was calculated for a subset using the intraclass correlation coefficient, ICC(A, 1). Construct validity was assessed by (a) comparing the weeklong vocal effort ratings between the patient and control groups and (b) comparing weeklong vocal effort ratings before and after voice rehabilitation in a subset of 25 patients. Cohen's d, the standard error of measurement (SEM), and the minimal detectable change (MDC) assessed sensitivity. The minimal clinically important difference (MCID) assessed responsiveness. Results Test-retest reliability was excellent, ICC(A, 1) = .96. Weeklong mean effort was statistically higher in the patients than in controls (d = 1.62) and lower after voice rehabilitation (d = 1.75), supporting construct validity and sensitivity. SEM was 4.14, MDC was 11.47, and MCID was 9.74. Since the MCID was within the error of the measure, we must rely upon the MDC to detect real changes in ecological vocal effort. Conclusion The ecological vocal effort scale offers a reliable, valid, and sensitive method of monitoring vocal effort changes during the daily life of individuals with and without vocal hyperfunction.

Determining Medical Urgency of Voice Disorders Using Auditory-Perceptual Voice Assessments Performed by Speech-Language Pathologists

OBJECTIVE

This study examined whether speech-language pathologist auditory-perceptual voice assessments can predict the medical urgency of voice disorders.

METHODS

Twenty speech-language pathologists (SLPs) evaluated 25 voice samples recorded during initial voice evaluations. Voice samples represented a range of dysphonia severity (mild-severe) balanced across patient diagnoses. Diagnoses included: benign lesions, laryngeal cancer, non-organic voice disorders, laryngeal edema (associated with LPR), and laryngeal paralysis or paresis. Laryngeal cancer and severe unilateral laryngeal paralysis were considered urgent disorders. While blinded to patient information, SLPs rated severity of voice quality, predicted patient diagnosis, and determined whether the patient should be seen urgently by a laryngologist. SLPs were then given basic medical history information and rated medical urgency of voice disorder a second time.

RESULTS

On average, SLPs correctly identified 65% of urgent voices and 87% of nonurgent voices when blinded to patient information. Accuracy improved significantly to 86% for urgent voices with medical history information (P < .001) and decreased to 77% for nonurgent voices. Accuracy was better when severity of voice quality was severe for urgent voices and mild for nonurgent voices (P < .001). SLPs indicated that patient smoking history and severity of dysphonia were most influential in their decision making. Diagnostic accuracy of auditory-perceptual assessments was poor.

CONCLUSIONS

SLPs identified 86% of medically urgent voice disorders when auditory perceptual assessments were combined with medical history information. Further work is needed to determine what medical history information is most crucial to rating accuracy and what speech tasks might best separate urgent and nonurgent patients.

Restoration Strategies Following Short-Term Vocal Exertion in Healthy Young Adults

Purpose This study aims to investigate the effects of a 10-min vocal exertion task on voice and respiratory measures, to determine whether restorative strategies can mitigate these effects after cessation of exertion, and to assess whether these strategies continue to reduce these detrimental effects when vocal exertion is resumed. Method A prospective, repeated-measures design was used. On consecutive days, 20 participants (equal men and women) completed two vocal exertion tasks separated by 10 min of restoration strategies: vocal rest or controlled phonation (low-level tissue mobilization using straw phonation). Voice and respiratory data were collected at baseline, following the first exertion task, after restoration strategies, and after the second exertion task. Outcome measures included (a) vocal effort, (b) phonation threshold pressure, (c) maximum and minimum fundamental frequencies, (d) cepstral peak prominence of connected speech, (e) lung volume initiation and termination, (f) percent vital capacity expended per syllable, and (g) number of syllables per breath group. Results A worsening of phonation threshold pressure (p < .001), vocal effort (p < .001), and increase of minimum fundamental frequency (p = .007) were observed after vocal exertion. Lung volume initiation (p < .001) and lung volume termination (p < .001) increased. These changes were largely reversed by restoration strategies, but only controlled phonation prevented exertion-induced changes in respiratory kinematic measures on a subsequent vocal exertion task. Conclusions Exertion-induced voice changes occur rapidly and may be mitigated by either controlled phonation or vocal rest. Controlled phonation is recommended as a superior strategy due to evidence of a protective effect on a successive vocal exertion task.

Relationship Between Tasked Vocal Effort Levels and Measures of Vocal Intensity

Purpose Patients with voice problems commonly report increased vocal effort, regardless of the underlying pathophysiology. Previous studies investigating vocal effort and voice production have used a range of methods to quantify vocal effort. The goals of the current study were to use the Borg CR100 effort scale to (a) demonstrate the relation between vocal intensity or vocal level (dB) and tasked vocal effort goals and (b) investigate the repeated measure reliability of vocal level at tasked effort level goals. Method Three types of speech (automatic, read, and structured spontaneous) were elicited at four vocal effort level goals on the Borg CR100 scale (2, 13, 25, and 50) from 20 participants (10 females and 10 males). Results Participants' vocal level reliably changed approximately 5 dB between the elicited effort level goals; this difference was statistically significant and repeatable. Biological females produced a voice with consistently less intensity for a vocal effort level goal compared to biological males. Conclusions The results indicate the utility of the Borg CR100 in tracking effort in voice production that is repeatable with respect to vocal level (dB). Future research will investigate other metrics of voice production with the goal of understanding the mechanisms underlying vocal effort and the external environmental influences on the perception of vocal effort.

Are Indoor Cycling Instructors Riding Their Way to Vocal Injury? Acute Effects of a Single Class on Measures of Voice Production

OBJECTIVE/HYPOTHESIS

There is an increased need for vocal education programs in group fitness instructors due to the reported risk of phonotraumatic injury in this population. Most research has focused on aerobics class instructors with limited research detailing the vocal demand response of cycling instruction, specifically. We hypothesized that instruction of a single indoor cycling class would produce evidence of acute vocal fold edema manifested by worsening of acoustic and self-perceptual voice measures and changes in ratings of laryngeal appearance.

STUDY DESIGN

Prospective Cohort study.

METHODS

Acoustic and self-perceptual voice measures that were potentially sensitive to laryngeal edema were collected from ten cycling instructors (Mean age: 31 ± 6.14 years, 3M and 7F) before and after instruction of a typical 45-minute cycling class. Two laryngologists then rated pairs of laryngeal exams from five instructors (Mean age: 30 ± 6.22 years, 1M and 4F) on the measure of vocal fold edema using a 10-inch Visual Analogue Scale. Paired t-test comparisons were completed on normalized data to compare pre- and postinstruction.

RESULTS

Majority of acoustic and self-perceptual measures significantly worsened following cycling instruction but the magnitude of change in these measures were small. In terms of laryngeal appearance, no measurable change in vocal fold edema was observed at both time points.

CONCLUSION

The vocal demand response to a single cycling class may be insufficient to cause significant vocal fold edema in our cycling instructors. Future research is required to determine the effects of repeated cycling instruction.

Investigation of Vocal Fatigue Using a Dose-Based Vocal Loading Task

Vocal loading tasks are often used to investigate the relationship between voice use and vocal fatigue in laboratory settings. The present study investigated the concept of a novel quantitative dose-based vocal loading task for vocal fatigue evaluation. Ten female subjects participated in the study. Voice use was monitored and quantified using an online vocal distance dose calculator during six consecutive 30-min long sessions. Voice quality was evaluated subjectively using the CAPE-V and SAVRa before, between, and after each vocal loading task session. Fatigue-indicative symptoms, such as cough, swallowing, and voice clearance, were recorded. Statistical analysis of the results showed that the overall severity, the roughness, and the strain ratings obtained from CAPE-V obeyed similar trends as the three ratings from the SAVRa. These metrics increased over the first two thirds of the sessions to reach a maximum, and then decreased slightly near the session end. Quantitative metrics obtained from surface neck accelerometer signals were found to obey similar trends. The results consistently showed that an initial adjustment of voice quality was followed by vocal saturation, supporting the effectiveness of the proposed loading task.

Resonance Effects and the Vocalization of Speech

Studies of the respiratory and laryngeal actions required for phonation are central to our understanding of both voice and voice disorders. The purpose of the present article is to highlight complementary insights about voice that have come from the study of vocal tract resonance effects.

Vibrational Therapies for Vocal Fatigue

BACKGROUND

Vibration is commonly used to relax tension in the limb and truck muscle. Vibration used directly on the muscle concerned and vertical vibration used on the whole-body through a foot platform have been reported in the literature to be useful to release muscle tension.

AIM

The present study investigated the effect of indirect whole-body vibration (WBV) and direct localized perilaryngeal vibration (LPV) on the phonatory functions of nondysphonic individuals with vocal fatigue.

METHODS

Forty-four subjects (mean age = 21.67 years) with normal voice, were randomly assigned to either the WBV group, the LPV group, or the Control (sham hand-held vibratory device) group. They performed karaoke singing for at least 95 minutes. They then received either WBV through a Turbosonic vibratory machine, LPV with a Novofan vibrator, or a sham vibrator for 10 minutes. The highest pitch produced, and self-reported vocal fatigue score were taken before singing, after singing, and after the intervention. Data were analyzed separately for the gender subgroups.

RESULTS

All subject groups showed significant reduction of vocal function (highest pitch production, and vocal fatigue score) after singing. Following the vibrational interventions, both the WBV and LPV groups showed significantly recovery in the highest pitch production and the perception of vocal fatigue (P < 0.002) than the Control groups.

CONCLUSION

Vibrational therapy, whether it is localized vibration on the peri-laryngeal muscles, or whole-body vibration, is more effective than voice rest per se in relieving vocal fatigue. Vibrational methods are recommended for treating vocal fatigue.

Test-Retest Reliability of Relative Fundamental Frequency and Conventional Acoustic, Aerodynamic, and Perceptual Measures in Individuals With Healthy Voices

Purpose Recent studies have shown that an acoustic measure, relative fundamental frequency (RFF), has potential for the assessment of excessive laryngeal tension and vocal effort associated with functional and neurological voice disorders. This study presents an analysis of the test-retest reliability of RFF in individuals with healthy voices and a comparison of reliability between RFF and conventional measures of voice. Method Acoustic and aerodynamic measurements and Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) were performed on 28 individuals with healthy voices on 5 consecutive days. Participants produced RFF stimuli, a sustained /ɑ/, and a reading passage to allow for extraction of acoustic measures and CAPE-V ratings; /pa/ trains were produced to allow for extraction of aerodynamic measures. Results Moderate reliabilities (intraclass correlation coefficient [ICC] = .64-.71) were found for RFF values. Mean vocal fundamental frequency, smoothed cepstral peak prominence, shimmer, harmonics-to-noise ratio, and mean airflow rate exhibited good-to-excellent reliabilities (ICC = .76-.99). ICCs for jitter and phonation threshold pressure were moderately reliable (ICC = .67-.74). ICCs for subglottal pressure estimates and all CAPE-V parameters showed poor reliabilities (ICC = .31-.58). Conclusion RFF has comparable reliability to conventional measures of voice. This expands the potential for clinical application of RFF. Supplemental Material https://doi.org/10.23641/asha.8233376.

Magnitude of Neck-Surface Vibration as an Estimate of Subglottal Pressure During Modulations of Vocal Effort and Intensity in Healthy Speakers

PURPOSE

This study examined the relationship between the magnitude of neck-surface vibration (NSVMag; transduced with an accelerometer) and intraoral estimates of subglottal pressure (P'sg) during variations in vocal effort at 3 intensity levels.

METHOD

Twelve vocally healthy adults produced strings of /pɑ/ syllables in 3 vocal intensity conditions, while increasing vocal effort during each condition. Measures were made of P'sg (estimated during stop-consonant closure), NSVMag (measured during the following vowel), sound pressure level, and respiratory kinematics. Mixed linear regression was used to analyze the relationship between NSVMag and P'sg with respect to total lung volume excursion, levels of lung volume initiation and termination, airflow, laryngeal resistance, and vocal efficiency across intensity conditions.

RESULTS

NSVMag was significantly related to P'sg (p < .001), and there was a significant, although small, interaction between NSVMag and intensity condition. Total lung excursion was the only additional variable contributing to predicting the NSVMag-P'sg relationship.

CONCLUSIONS

NSVMag closely reflects P'sg during variations of vocal effort; however, the relationship changes across different intensities in some individuals. Future research should explore additional NSV-based measures (e.g., glottal airflow features) to improve estimation accuracy during voice production.

Self-Ratings of Vocal Status in Daily Life: Reliability and Validity for Patients With Vocal Hyperfunction and a Normative Group

PURPOSE

The aim of this study was to establish reliability and validity for self-ratings of vocal status obtained during the daily activities of patients with vocal hyperfunction (VH) and matched controls.

METHOD

Eight-four patients with VH and 74 participants with normal voices answered 3 vocal status questions-difficulty producing soft, high-pitched phonation (D-SHP); discomfort; and fatigue-on an ambulatory voice monitor at the beginning, 5-hr intervals, and the end of each day (7 total days). Two subsets of the patient group answered the questions during a 2nd week after voice therapy (29 patients) or laryngeal surgery (16 patients).

RESULTS

High reliability resulted for patients (Cronbach's α = .88) and controls (α = .95). Patients reported higher D-SHP, discomfort, and fatigue (Cohen's d = 1.62-1.92) compared with controls. Patients posttherapy and postsurgery reported significantly improved self-ratings of vocal status relative to their pretreatment ratings (d = 0.70-1.13). Within-subject changes in self-ratings greater than 20 points were considered clinically meaningful.

CONCLUSIONS

Ratings of D-SHP, discomfort, and fatigue have adequate reliability and validity for tracking vocal status throughout daily life in patients with VH and vocally healthy individuals. These questions could help investigate the relationship between vocal symptom variability and putative contributing factors (e.g., voice use/rest, emotions).

Factors associated with vocal fry among college students

PURPOSE

Vocal fry is increasingly used in everyday speech. The purpose of this study was to identify associated factors of vocal fry among young US college-age students.

METHODS

Forty college students participated in a cross-sectional study. Participants produced speech under nine different room acoustic conditions (simulated). The recorded speech was perceptually evaluated by three speech-language pathologists. Multivariate logistic regression analysis was used to identify variables (individual, environmental) associated with the perceptual assessment of vocal fry.

RESULTS

A high occurrence of perceptually identified vocal fry was identified among college students. Two factors were significantly associated with lower occurrence of perceptually identified vocal fry: one individual (sporadic consumption of caffeinated beverages) and one environmental factor (speaking in an environment with background noise).

CONCLUSIONS

Similar to modal phonation, fry-like phonation seems to be influenced by individual and environmental factors. Therefore, clinicians interested in including this technique as part of their intervention programs may take into account the caffeine consumption and the background noise conditions of the room where the therapy will take place in order to facilitate the production of fry-like phonation.

Vocal Loading and Environmental Humidity Effects in Older Adults

The goal of this study was to investigate the effects of a vocal loading challenge that combined prolonged speaking, in child-directed voice within a noisy environment, in older adults. An additional goal was to determine whether increased environmental humidity would attenuate the negative effects of this vocal loading challenge.

METHOD

Thirteen healthy subjects (five males and eight females; >65 years) completed a vocal loading challenge. The challenge involved 45 minutes of child-directed speech in the presence of 65 dB multitalker babble background noise. Subjects completed this challenge in both low humidity and moderate humidity in counterbalanced order. Vocal function was assessed before and after the challenge using phonation threshold pressure (PTP), cepstral peak prominence (CPP), low/high spectral ratio (LHR), perceived phonatory effort (PPE), and perceived vocal tiredness.

RESULTS

Negative changes were observed in the aging larynx following the 45-minute vocal loading challenge. Measures of PTP, PPE, and perceived vocal tiredness demonstrated statistically significant loading effects. Increased ambient humidity significantly alleviated the negative changes observed in PPE and perceived vocal tiredness. Increased humidity significantly improved CPP measures both before and after the vocal loading challenge.

CONCLUSIONS

This study furthers our understanding of how older adults respond to a vocal loading challenge of prolonged nonhabitual speech in a noisy environment. Our data suggest that the aging voice is negatively affected by prolonged loud speaking and that humidification may be beneficial in reducing some of these negative effects.

Teachers and Teaching: Speech Production Accommodations Due to Changes in the Acoustic Environment

School teachers have an elevated risk of voice problems due to the vocal demands in the workplace. This manuscript presents the results of three studies investigating teachers' voice use at work. In the first study, 57 teachers were observed for 2 weeks (waking hours) to compare how they used their voice in the school environment and in non-school environments. In a second study, 45 participants performed a short vocal task in two different rooms: a variable acoustic room and an anechoic chamber. Subjects were taken back and forth between the two rooms. Each time they entered the variable acoustics room, the reverberation time and/or the background noise condition had been modified. In this latter study, subjects responded to questions about their vocal comfort and their perception of changes in the acoustic environment. In a third study, 20 untrained vocalists performed a simple vocal task in the following conditions: with and without background babble and with and without transparent plexiglass shields to increase the first reflection. Relationships were examined between [1] the results for the room acoustic parameters; [2] the subjects' perception of the room; and [3] the recorded speech acoustic. Several differences between male and female subjects were found; some of those differences held for each room condition (at school vs. not at school, reverberation level, noise level, and early reflection).

Comparison of Vocal Vibration-Dose Measures for Potential-Damage Risk Criteria

PURPOSE

Schoolteachers have become a benchmark population for the study of occupational voice use. A decade of vibration-dose studies on the teacher population allows a comparison to be made between specific dose measures for eventual assessment of damage risk.

METHOD

Vibration dosimetry is reformulated with the inclusion of collision stress. Two methods of estimating amplitude of vocal-fold vibration are compared to capture variations in vocal intensity. Energy loss from collision is added to the energy-dissipation dose. An equal-energy-dissipation criterion is defined and used on the teacher corpus as a potential-damage risk criterion.

RESULTS

Comparison of time-, cycle-, distance-, and energy-dose calculations for 57 teachers reveals a progression in information content in the ability to capture variations in duration, speaking pitch, and vocal intensity. The energy-dissipation dose carries the greatest promise in capturing excessive tissue stress and collision but also the greatest liability, due to uncertainty in parameters. Cycle dose is least correlated with the other doses.

CONCLUSION

As a first guide to damage risk in excessive voice use, the equal-energy-dissipation dose criterion can be used to structure trade-off relations between loudness, adduction, and duration of speech.

Teacher response to ambulatory monitoring of voice

Voice accumulation and dosimetry devices are used for unobtrusive monitoring of voice use. While numerous studies have used these devices to examine how individuals use their voices, little attention has been paid to how subjects respond to them. Therefore, the purpose of this short communication is to begin to explore two questions: 1) How do voice monitoring devices affect daily communication? and 2) How do participants feel about the physical design and function of these types of voice monitoring devices? One key finding is that most of the subjects remain aware of the dosimeter while wearing it, which may impact the data collected. Further, most subjects have difficulty with the accelerometer and/or the data storage device.

Towards a self-rating tool of the inability to produce soft voice based on nonlinear events: a preliminary study

The purpose of this preliminary study was to investigate the feasibility of a tool to compare a severity index of nonlinear events and vocal self-rating over a long period of time. One hundred and ninety-seven phonations were analyzed to quantify the severity of instabilities in the voice attributed to nonlinear dynamic phenomena, including voice breaks, subharmonics, and frequency jumps. Instabilities were first counted; then a severity index was calculated for the instabilities in each phonation. The two quantities were compared to the subject's autoperceptual rating. Generally speaking, the measures derived from nonlinear dynamic analysis of the high-pitched, soft phonations followed the subject's own rating of inability to produce soft voice. These preliminary single subject results provide a foundation for future multi-subject studies to formulate acoustic and autoperceptual measures for the fatiguing effects of prolonged speaking in vocally demanding professions. However, given the number of observations, the results are still useful in showing general relationships. While future work should add additional subjects, a study providing preliminary evidence is useful before attempting to undertake a multi-subject study with complex analysis (i.e., individually selecting the nonlinear events) and with a long observation duration (days, weeks, and months) of subject.