Investigations into vocal doses and parameters pertaining to primary school teachers in classrooms

Voice use of nurses working in the intensive care unit during the COVID-19 pandemic

OBJECTIVE

This study aimed to investigate the voice use of nurses working in intensive care units (ICUs) and their perception of acoustic environments.

SETTING AND SAMPLE

The research was conducted in four different hospitals in China during the COVID-19 pandemic. A total of 60 ICU nurses were recruited for their voice use monitoring and 100 nurses participated in the survey.

RESEARCH METHODOLOGY

Firstly, voice-related parameters such as voice level (SPL, dB), fundamental frequency (F0, Hz), and voicing time percentage (Dt, %) were measured using a vocal monitor. To collect data, a non-invasive accelerometer was attached to the participants' necks during their working hours. Secondly, the perception of the ICU acoustic environment was assessed using semantic differential.

RESULTS

The results showed that nurses spoke approximately 0.9-4 dB louder to patients and colleagues in ICUs compared to quiet rooms, and their fundamental frequency (F0) significantly increased during work. The voice levels of nurses were influenced by background noise levels, with a significant correlation coefficient of 0.44 (p < 0.01). Furthermore, the background noise levels ranged from 58.1 to 73.9 dBA, exceeding the guideline values set by the World Health Organisation (WHO). The semantic differential analysis identified 'Stress' and 'Irritation' as the two main components, indicating the prevalence of negative experiences within ICUs.

IMPLICATIONS FOR CLINICAL PRACTICE

This study highlights the potential risk of voice disorders among ICU nurses. The findings also underscore the importance of implementing strategies to reduce noise levels in ICUs to reduce voice disorders among nurses.

Quantifying the Occupational Voice Use of Teachers

Purpose

The teaching profession is a high-voice use occupation at elevated risk for developing voice disorders. Continued research on teachers' vocal demands is necessary to advocate for and establish vocal health programs. This study quantified ambulatory vocal dose measures for teachers during both on- and off-work periods, comparing their occupational voice use to that in other studies that have reported percent phonation ranging from 17% to 30%.

Method

Participants included 26 full-time, female school teachers between 23 and 55 years of age across multiple grades and subjects, including individuals with and without a voice disorder. Ambulatory voice data were collected from weeklong voice monitoring that recorded phonatory activity through anterior neck-surface vibration. Three vocal dose measures-time, cycle, and distance doses-were computed for each participant for three time periods: on-work weekdays, off-work weekdays, and off-work weekend days.

Results

The teachers' average percent phonation was 16.2% on-work weekdays, 8.4% off-work weekdays, and 8.0% off-work weekend days. No statistically significant differences for vocal dose measures were found between off-work weekdays and weekend days. Overall, all vocal dose measures were approximately 2 times higher during work relative to off-work time periods.

Conclusions

This study provides values for vocal dose measures for school teachers using ambulatory voice-monitoring technology. The vocal demands of this particular teacher sample and voice activity detection algorithm are potential factors contributing to percent phonation values on the lower end of the range reported in the literature. Future work is needed to continue to understand occupational voice use and its associated risks related to voice health, with the ultimate goal of preventing and managing voice disorders in individuals engaged in high-risk occupations.

Classroom Acoustics for Enhancing Students' Understanding When a Teacher Suffers From a Dysphonic Voice

PURPOSE

The purpose of this project is to assess the acoustical conditions in which optimal intelligibility and low listening difficulty can be achieved in real classrooms for elementary students, taking into consideration the effects of dysphonic voice and typical classroom noise.

METHOD

Speech intelligibility tests were performed in six elementary classrooms with 80 normal-hearing students aged 7-11 years. The speech material was produced by a female actor using a normal voice quality and simulating a dysphonic voice. The stimuli were played by a Head and Torso Simulator. Child babble noise and classrooms with different reverberation times were used to obtain a Speech Transmission Index (STI) range from 0.2 to 0.7, corresponding to the categories bad, poor, fair, and good.

RESULTS

The results showed a statistically significant decrease in intelligibility when the speaker was dysphonic, in STI higher than 0.33. The rating of listening difficulty showed a significantly greater difficulty in perceiving the dysphonic voice. In addition, younger children showed poorer performance and greater listening difficulty compared with older children when listening to the normal voice quality. Both groups were equally impacted when the voice was dysphonic.

CONCLUSIONS

The results suggested that better acoustic conditions are needed for children to reach a good level of intelligibility and to reduce listening difficulty if the teacher is suffering from voice problems. This was true for children regardless of grade level, highlighting the importance of ensuring more favorable acoustic conditions for children throughout all elementary schools.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23504487.

The Influence of Multisensory Input On Voice Perception and Production Using Immersive Virtual Reality

OBJECTIVES

The purpose was to examine the influence of auditory vs visual vs combined audiovisual input on perception and production of one's own voice, using immersive virtual reality technology.

METHODS

Thirty-one vocally healthy men and women were investigated under 18 sensory input conditions, using immersive virtual reality technology. Conditions included two auditory rooms with varying reverberation times, two visual rooms with varying volumes, and the combination of audiovisual conditions. All conditions were repeated with and without background noise. Speech tasks included counting, sustained vowel phonation, an all-voiced sentence from the Consensus Auditory-Perceptual Evaluation of Voice, and the first sentence from the Rainbow Passage, randomly ordered. Perception outcome measures were participants' self-reported perceptions of their vocal loudness, vocal effort, and vocal comfort in speech. Production outcome measures were sound pressure level (SPL) and spectral moments (spectral mean and standard deviation in Hz, skewness, and kurtosis). Statistical analyses used self-reported vocal effort, vocal loudness, and vocal comfort in percent (0 = "not at all," 100 = extremely), SPL in dB, and spectral moments in Hz. The reference level was a baseline audiovisual deprivation condition.

RESULTS

Results suggested (i) increased self-perceived vocal loudness and effort, and decreased comfort, with increasing room volume, speaker-to-listener distance, audiovisual input, and background noise, and (ii) increased SPL and fluctuations in spectral moments across conditions.

CONCLUSIONS

Not only auditory, but also visual and audiovisual input influenced voice perception and production in ways that have not been previously documented. Findings contribute to the basic science understanding the role of visual, audiovisual and auditory input in voice perception and production, and also to models of voice training and therapy. The findings also set the foundation for the use of virtual reality in voice and speech training, as a potentially power solution to the generalization problem.

Mapping the Landscape of Voice Complaints among Teachers: A Bibliometric Investigation

PURPOSE

With the significant and growing interest in voice disorders among teachers over the last several decades, there is value in having a comprehensive overview of the current state of the field and its related research productivity. This study aims to provide an updated and comprehensive mapping of the intellectual structure and research evolution in the field of occupational voice complaints among teachers.

METHODS

A systematic review of scientific articles on occupational voice complaints among teachers published in the last two decades was conducted using the preferred reporting items for systematic reviews and meta-analyses statements. A retrospective bibliometric analysis was then performed using the Web of Science core collection and VOSviewer to identify scientific productivity indicators, including publications per year, productivity by country, journals, and most cited articles.

RESULTS

Based on the search eligibility criteria, a total of 473 articles were initially screened, and from this selection, 157 articles were identified as meeting the inclusion criteria and therefore included in the analysis. The analysis revealed a strong trend in scientific productivity, with a 300% increase in the number of publications during the last decade. The leading countries in publications on this field were Brazil, the United States, and Finland. The Journal of Voice, CoDAS, and Folia Phoniatrica et Logopaedica were the most frequently published journals. Additionally, the literature on voice complaints among teachers primarily focused on five conceptual clusters: vocal demand response, voice disorders, vocal health promotion, individual-associated factors, and voice symptoms.

CONCLUSION

This study examines the growing literature on voice complaints among teachers over the past 20 years, identifying key countries, journals, and thematic clusters. The findings have important implications for researchers, policymakers, and practitioners, providing insights for collaboration and guiding future advancements in the field.

Do-It-Yourself Voice Dosimeter Device: A Tutorial and Performance Results

PURPOSE

Voice dosimeters gather voice production data in the daily lives of individuals with voice disorders. Additionally, voice dosimeters aid in understanding the pathophysiology of voice disorders. Previously, several voice dosimeters were commercially available. However, these devices have been discontinued and are not available to clinicians and researchers alike. In this tutorial, instructions for a low-cost, easy-to-assemble voice dosimeter are provided. This do-it-yourself (DIY) voice dosimeter is further validated based on performance results.

METHOD

Ten vocally healthy participants wore the DIY voice dosimeter. They produced a sustained /a/ vowel and read a text with three different vocal efforts. These tasks were recorded by the DIY voice dosimeter and a reference microphone simultaneously. The expanded uncertainty of the mean error in the estimation of four voice acoustic parameters as measured by the DIY dosimeter was performed by comparing the signals acquired through the reference microphone and the dosimeter.

RESULTS

For measures of sound pressure level, the DIY voice dosimeter had a mean error of -0.68 dB with an uncertainty of 0.56 dB. For fundamental frequency, the mean error was 1.56 Hz for female participants and 1.11 Hz for male participants, with an uncertainty of 0.62 Hz and 0.34 Hz for female and male participants, respectively. Cepstral peak prominence smoothed and L₁ minus L₂ had mean errors (uncertainty) of -0.06 dB (0.27 dB) and 2.20 dB (0.72 dB).

CONCLUSION

The mean error and uncertainties for the DIY voice dosimeter are comparable to those for the most accurate voice dosimeters that were previously on the market.

Self-reported Vocal Demands, Perceptions, and Knowledge of Occupational Voice Users in South Africa

OBJECTIVES

The study aimed to describe daily vocal demands, perceptions and knowledge as reported by occupational voice users.

STUDY DESIGN

A descriptive, cross-sectional research design was employed.

METHODS

A survey on vocal demands, perceptions and knowledge was distributed to 102 occupational voice users via a snowball sampling technique.

RESULTS

Slightly more than half of the participants (55%) reported using their voice for work 36.5 hours a week on average (SD = 15.5, range: 33-40). Participants reported that, on average, their daily voice use is 6.3 hours (SD = 2.7) for work and the majority (81%) reported a decrease in voice quality after work; Three-quarters (75%) also reported vocal fatigue at the end of day. Approximately one-third (33%) reported being exposed to environments where they are expected to shout, scream or cheer loudly. More than half of the participants (61%) reported that they have previously received vocal health education but 40% reported that they felt this training was insufficient. High vocal demands are significantly correlated to an increase in perceived vocal handicap rs = 0.242; (P = 0.018), tiredness of voice rs = 0.270; (P = 0.008), physical discomfort rs = 0.217; (P = 0.038) as well as how occupational voice users experience improvement of symptoms with rest rs = -0.356 (P < 0.001). Other risk factors highlighted by occupational voice users are the ingestion of liquid caffeine, alcohol, and carbonated drinks, smoking or the presence of chronic cough, chronic laryngitis, and gastroesophageal reflux disease.

CONCLUSIONS

Occupational voice users are subjected to high daily vocal demands that can be seen to be linked to vocal fatigue, changes in voice quality and vocal symptoms experienced. It is essential that occupational voice users as well as treating clinicians are aware of certain significant predictors of both vocal handicap and vocal fatigue. These findings provide insights for developing strategies for training and cultivating vocal health consciousness and preventive voice care initiatives that focus on occupational voice users in South Africa.

A basic protocol for the acoustic characterization of small and medium-sized classrooms

To promote a fast and effective characterization of the sound environment in small and medium-sized classrooms, a basic measurement protocol, based on a minimum number of parameters and positions, is provided. Measurements were taken in 29 occupied classrooms belonging to 13 primary schools in Turin, Italy, that differ in location and typology. The background noise level was acquired during silent and group activities, and the reverberation time, speech clarity, useful-to-detrimental ratio and speech level, were acquired along the main axis of each classroom and in one or two offset positions. To reduce the number of measured parameters that can be used to fully characterize classroom acoustics, data were divided into two groups on the basis of a cutoff value of maximum occupied reverberation time in the case of moderate and severe requirements. Given the strong correlation among the quantities, thresholds were identified for the other acoustical parameters, and their accuracy and precision were tested to assess their ability to classify the acoustic quality as compliant or non-compliant. Results suggest that more convenient parameters, like clarity in the central position of the classroom, can be used instead of reverberation time to classify classroom acoustics.

Speech and noise levels measured in occupied K-12 classrooms

This project acquired sound levels logged across six school days and impulse responses in 220 classrooms across four K-12 grades. Seventy-four percent met reverberation time recommendations. Sound levels were processed to estimate occupied signal-to-noise ratios (SNRs), using Gaussian mixture modeling and from daily equivalent and statistical levels. A third method, k-means clustering, estimated SNR more precisely, separating data on nine dimensions into one group with high levels across speech frequencies and one without. The SNRs calculated as the daily difference between the average levels for the speech and non-speech clusters are found to be lower than 15 dB in 27.3% of the classrooms and differ from using the other two methods. The k-means data additionally indicate that speech occurred 30.5%-81.2% of the day, with statistically larger percentages found in grade 3 compared to higher grades. Speech levels exceeded 65 dBA 35% of the day, and non-speech levels exceeded 50 dBA 32% of the day, on average, with grades 3 and 8 experiencing speech levels exceeding 65 dBA statistically more often than the other two grades. Finally, classroom speech and non-speech levels were significantly correlated, with a 0.29 dBA increase in speech levels for every 1 dBA in non-speech levels.

Unsupervised analysis of background noise sources in active offices

Inside open-plan offices, background noise affects the workers' comfort, influencing their productivity. Recent approaches identify three main source categories: mechanical sources (air conditioning equipment, office devices, etc.), outdoor traffic noise, and human sources (speech). Whereas the first two groups are taken into account by technical specifications, human noise is still often neglected. The present paper proposes two procedures, based on machine-learning techniques, to identify the human and mechanical noise sources during working hours. Two unsupervised clustering methods, specifically the Gaussian mixture model and K-means clustering, were used to separate the recorded sound pressure levels that were recorded while finding the candidate models. Thus, the clustering validation was used to find the number of sound sources within the office and, then, statistical and metrical features were used to label the sources. The results were compared with the common parameters used in noise monitoring in offices, i.e., the equivalent continuous and 90th percentile levels. The spectra obtained by the two algorithms match with the expected shapes of human speech and mechanical noise tendencies. The outcomes validate the robustness and reliability of these procedures.

Comparison of vocal fatigue and vocal tract discomfort between teachers of normal pupils and teachers of mentally disabled pupils

PURPOSE

This study aims to study the comparison of vocal fatigue and vocal tract discomfort between teachers of normal pupils and teachers of mentally disabled pupils.

STUDY DESIGN

Cross-sectional study METHODS: Participants were 179 teachers (50 male, 129 female) and 30 non-teachers (14 male, 16 female) who participated in the current study. The teachers work in elementary schools. Furthermore, 87 of the teachers work for mentally disabled pupils at special elementary schools. Non-teachers were Ahvaz Jundishapur University of Medical Sciences employees who consider as the control group. They completed the Persian VFI and VTDp questionnaires three times, at the beginning, middle, and end of their office hours for 1 workday.

RESULTS

The current study's findings indicate that the Persian VFI and VTD scores of non-teachers were significantly lower than teachers' scores. Furthermore, teachers of mentally disabled pupils demonstrated higher values from teachers of normal pupils based on the Persian VFI and VTDp scores CONCLUSION: The study results showed that teachers experienced more vocal fatigue and vocal tract discomfort than non-teachers. Furthermore, teachers of mentally disabled pupils indicated more vocal fatigue, the larynx's physical discomfort, and vocal tract discomfort, but this difference was practically small.

Which teachers are most at risk for voice disorders? Individual factors predicting vocal acoustic parameters monitored in situ during a workweek

PURPOSE

To identify the factors affecting teachers' vocal acoustic parameters, with the aim of detecting individuals at risk of phonotrauma.

METHOD

The voicing time, voice sound pressure level [SPL] and fundamental frequency [f_o] of 87 teachers were measured during one workweek using a voice dosimeter. We retrospectively investigated the impact of 10 factors (gender, age, teaching experience, teaching level, tobacco, gastro-esophageal problems, nonoccupational voice activity, voice education, past voice problems, and biopsychosocial impact of voice problems measured using the Voice Handicap Index [VHI]) on each voice parameter.

RESULTS

None of the above factors affected voicing time or SPL. f_o depended significantly on gender, teaching level, nonoccupational voice activity and VHI score. Specifically, f_o was higher in women (Δ = 69 Hz), in individuals without nonoccupational voice activities (Δ = 11 Hz), and in individuals with a lower VHI score (increase of 0.7 Hz for each additional point). For females, post hoc comparisons revealed a substantial impact of teaching level on f_o: university instructors had deeper voices than kindergarten (Δ = 66 Hz), elementary (Δ = 52 Hz), or secondary teachers (Δ = 41 Hz).

CONCLUSIONS

Since higher f_o increases the mechanical stress related to vocal fold vibration, the screening and prevention of phonotrauma should focus primarily on women, particularly those who teach at lower levels, and teachers with more self-rated voice problems. The lower f_o of teachers who engage in nonprofessional voice activities may suggest acute inflammation or muscle fatigue due to voice overload.

Acoustic Comfort as a Salutogenic Resource in Learning Environments—A Proposal for the Design of a System to Improve the Acoustic Quality of Classrooms

This article addresses the topic of environmental comfort from a salutogenic and pedagogical point of view. It begins by presenting a wide framework aimed at describing the complexity and specificity of the acoustic issue and the need to integrate decibel-based metrics with knowledge and reflections which are inherent to non-measurable factors. The article then focuses its attention on educational spaces and presents the results of an investigation carried out in 52 classrooms of 19 primary schools in Florence. From this research and keeping in mind the current Italian legislation, the following results are deduced: (1) the layout of a typical classroom, (2) the average reverberation time and (3) the sound-absorbing surface required to improve the acoustic quality of the typical classroom with polystyrene fibre panels. Subsequently, after having briefly described the more appropriate typology of sound-absorbing solutions, a system for the acoustic correction of classrooms is presented. This system is composed of two parts. The first part is fixed and its realisation is entrusted to specialised personnel; the second, based on the concept of personalisation and transformation of the educational space, is modifiable through time and designed and applied by the students themselves.

Investigating Listening Effort in Classrooms for 5- to 7-Year-Old Children

Purpose This study aims to investigate the listening effort made by young children in real classrooms during a prolonged speech reception task in the presence of background noise. Method The experiment was proposed to 117 typically developing kindergarten and primary school pupils, aged 5-7 years old. An ecological experimental approach was followed, and speech-in-noise tests were presented in the classrooms to groups made up of the whole class. The speech material of the Word Intelligibility by Picture Identification Test in the Italian language ( Arslan, Genovese, Orzan, & Turrini, 1997 ) was presented in 2 listening conditions (quiet classroom [no noise added] and working classroom [with stationary noise]) and was repeated twice during the experiment. Data on the number of correctly recognized words and the single-task response time (RT) were collected; the quantity of the latter was considered informative on listening effort. Results It was found that when background noise was present, the pupils' performance decreased, and greater RTs were required compared to the "quiet classroom" condition. When the RTs were analyzed over the course of the experiment, there were no changes in the quiet condition, whereas in the working classroom, a significant increase was found for the 6- and 7-year-old pupils. On the contrary, the youngest pupils (5-year-olds) showed a decrease in the RT results over the test repetitions. Conclusions The RT measured with a single-task paradigm was found to be a viable approach for investigating the listening effort in 6- to 7-year-old pupils. For this age range, the metric was sensitive to changes both in the listening conditions and within the same listening condition across the time of exposure. More research is needed to assess the feasibility of the experimental paradigm with the 5-year-old children.

Quality of Life and Acoustic Comfort in Educational Environments of Curitiba, Brazil

BACKGROUND

It is believed that poor classroom acoustics leads to lower levels of student learning and exposes teachers vocal folds to greater physical wear and tear.

OBJECTIVE

This study sought to compare the quality of life by World Health Organization (whoqol-bref) questionnaire of 61 teachers working at schools with different acoustic conditions.

METHODS

This paper reports on a descriptive exploratory study aimed at ascertaining the following: (1) outdoor sound pressure levels in the immediate surroundings of two primary schools; (2) background noise levels inside classrooms; (3) reverberation times in classrooms; (4) the teacher's perception of noise in the work environment; (5) the teacher's vocal intensity in the classroom; and (6) the teacher's perceived quality of life.

RESULTS

It was found that the quality of life of teachers, as well as the major causes of acoustic discomfort, do not stem from a source outside the classroom, halls, and physical education classes. Instead, they originate inside the classroom and are caused by students during school hours; the teachers' vocal intensity exceeds the limits of tolerability both in schools that provide acoustic comfort and in those that do not.

CONCLUSIONS

The basic conditions required to ensure the health of the participants in this study during their workday were found to be unsatisfactory.

Work-Related Communicative Profile of Voice Teachers: Effects of Classroom Noise on Voice and Hearing Abilities

PURPOSE

Vocal instructors during their normal workday are exposed to high noise levels that can affect their voice and hearing health. The goal of this study was to evaluate the voice and hearing status of voice instructors before and after lessons and relate these evaluations with voice and noise dosimetry taken during lessons.

METHODS

Eight voice instructors volunteered to participate in the study. The protocol included (1) questionnaires, (2) pre/post assessment of voice quality and hearing status, and (3) voice and noise dosimetry during lessons. Acoustic measurements were taken of the unoccupied classrooms.

RESULTS

In six of eight classrooms, the measured noise level was higher than the safety recommendations set by National Institute for Occupational Safety and Health. The background noise level and the reverberation time in the classrooms were in compliance with the national standard recommendations. We did not find a clear pattern comparing pre- and post-measurements of voice quality consistent among genders. In all subjects, the Sound Pressure Levels mean increased, and the standard deviation of fundamental frequency decreased indicating association to vocal fatigue. Previous studies link these changes to increasing vocal fatigue. The audiometric results revealed seven out of eight instructors have sensorineural hearing loss.

CONCLUSIONS

The interaction of the acoustic space and noise levels can contribute to the development of hearing and voice disorders for voice instructors. If supported by larger sample size, the results of this pilot study could justify the need for a hearing and voice conservation program for music faculty.

Ambulatory monitoring of Lombard-related vocal characteristics in vocally healthy female speakers

Speakers typically modify their voice in the presence of increased background noise levels, exhibiting the classic Lombard effect. Lombard-related characteristics during everyday activities were recorded from 17 vocally healthy women who wore an acoustic noise dosimeter and ambulatory voice monitor. The linear relationship between vocal sound pressure level and environmental noise level exhibited an average slope of 0.54 dB/dB and value of 72.8 dB SPL at 50 dBA when correlation coefficients were greater than 0.4. These results, coupled with analyses of spectral and cepstral vocal function measures, provide normative ambulatory Lombard characteristics for comparison with patients with voice-use related disorders.

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.

Differences in Weeklong Ambulatory Vocal Behavior Between Female Patients With Phonotraumatic Lesions and Matched Controls

Purpose Previous work using ambulatory voice recordings has shown no differences in average vocal behavior between patients with phonotraumatic vocal hyperfunction and matched controls. This study used larger groups to replicate these results and expanded the analysis to include distributional characteristics of ambulatory voice use and measures indicative of glottal closure. Method Subjects included 180 adult women: 90 diagnosed with vocal fold nodules or polyps and 90 age-, sex-, and occupation-matched controls with no history of voice disorders. Weeklong summary statistics (average, variability, skewness, kurtosis) of voice use were computed from neck-surface acceleration recorded using an ambulatory voice monitor. Voice measures included estimates of sound pressure level (SPL), fundamental frequency (f _o), cepstral peak prominence, and the difference between the first and second harmonic magnitudes (H1-H2). Results Statistical comparisons resulted in medium-large differences (Cohen's d ≥ 0.5) between groups for SPL skewness, f _o variability, and H1-H2 variability. Two logistic regressions (theory-based and stepwise) found SPL skewness and H1-H2 variability to classify patients and controls based on their weekly voice data, with an area under the receiver operating characteristic curve of 0.85 and 0.82 on training and test sets, respectively. Conclusion Compared to controls, the weekly voice use of patients with phonotraumatic vocal hyperfunction reflected higher SPL tendencies (negatively skewed SPL) with more abrupt glottal closure (reduced H1-H2 variability, especially toward higher values). Further work could examine posttreatment data (e.g., after surgery and/or therapy) to determine the extent to which these differences are associated with the etiology and pathophysiology of phonotraumatic vocal fold lesions.

Improved subglottal pressure estimation from neck-surface vibration in healthy speakers producing non-modal phonation

Subglottal air pressure plays a major role in voice production and is a primary factor in controlling voice onset, offset, sound pressure level, glottal airflow, vocal fold collision pressures, and variations in fundamental frequency. Previous work has shown promise for the estimation of subglottal pressure from an unobtrusive miniature accelerometer sensor attached to the anterior base of the neck during typical modal voice production across multiple pitch and vowel contexts. This study expands on that work to incorporate additional accelerometer-based measures of vocal function to compensate for non-modal phonation characteristics and achieve an improved estimation of subglottal pressure. Subjects with normal voices repeated /p/-vowel syllable strings from loud-to-soft levels in multiple vowel contexts (/ɑ/, /i/, and /u/), pitch conditions (comfortable, lower than comfortable, higher than comfortable), and voice quality types (modal, breathy, strained, and rough). Subject-specific, stepwise regression models were constructed using root-mean-square (RMS) values of the accelerometer signal alone (baseline condition) and in combination with cepstral peak prominence, fundamental frequency, and glottal airflow measures derived using subglottal impedance-based inverse filtering. Five-fold cross-validation assessed the robustness of model performance using the root-mean-square error metric for each regression model. Each cross-validation fold exhibited up to a 25% decrease in prediction error when the model incorporated multidimensional aspects of the accelerometer signal compared with RMS-only models. Improved estimation of subglottal pressure for non-modal phonation was thus achievable, lending to future studies of subglottal pressure estimation in patients with voice disorders and in ambulatory voice recordings.

Influence of Classroom Acoustics on Noise Disturbance and Well-Being for First Graders

Several studies have shown so far that poor acoustics inside classrooms negatively affects the teaching and learning processes, especially at the lowest grades of education. However, the extent to which noise exposure or excessive reverberation affect well-being of children at school in their early childhood is still unanswered, as well as their awareness of noise disturbance. This work is a pilot study to investigate to which extent classroom acoustics affects the perceived well-being and noise disturbance in first graders. About 330 pupils aged from 6 to 7 years participated in the study. They belonged to 20 classes of 10 primary schools located in Torino (Italy), where room acoustic measurements were performed and where noise level was monitored during classes. The school buildings and the classrooms were balanced between socioeconomic status and acoustic conditions. Trained experimenters administered questionnaires in each class, where pupils answered all together during the last month of the school year (May). Questions included the happiness scale, subscales assessing self-esteem, emotional health, relationship at home and with friends, enjoyment of school, intensity and noise disturbance due to different sound sources, and quality of voice. The findings of the study suggest that long reverberation times, which are associated with poor classroom acoustics as they generate higher noise levels and degraded speech intelligibility, bring pupils to a reduced perception of having fun and being happy with themselves. Furthermore, bad classroom acoustics is also related to an increased perception of noise intensity and disturbance, particularly in the case of traffic noise and noise from adjacent school environments. Finally, happy pupils reported a higher perception of noise disturbance under bad classroom acoustic conditions, whereas unhappy pupils only reported complaints in bad classroom acoustics with respect to the perception of pleasances with himself or herself and of fitting in at school. Being a mother tongue speaker is a characteristic of children that brings more chances of attending classes in good acoustics, of being less disturbed, and of having more well-being, and richer districts presented better acoustic conditions, in turn resulting in richer districts also revealing a greater perception of well-being.

Vocal Dose of Preservice Music Therapists, Preservice Music Teachers, and Other Undergraduate Students

BACKGROUND

Researchers have studied various populations with high vocal doses and prevalence of related voice disorders. Teachers, singers, and university students are three such populations that have been examined extensively. No studies to date, however, have examined the voice use of music therapists and compared their voice use to these other populations.

OBJECTIVE

The purpose of this investigation was to examine voice dosimeter data including phonation duration and percentage, amplitude, frequencies, and distance dose acquired over contiguous 7 day (1 week) periods by preservice music therapists, preservice music teachers, and other university students in concert with daily voice use surveys.

STUDY DESIGN

This is a quantitative descriptive design.

METHODS

Eight female students of varied majors (music therapy, music education, vocal performance, elementary education, and "other") in their third year of university study wore a voice dosimeter during all waking hours for 7 days. The dosimeter recorded voicing time, percentage, frequency, and estimated amplitude. Participants also completed surveys related to several parameters of vocal health, the number of hours they slept, and their voice care.

RESULTS

Participants experienced relatively low vocal doses during the week. Music majors experienced more voice use than nonmusic majors. Some of the highest doses occurred during teaching demonstrations and leading of music therapy practicum sessions.

CONCLUSION

Preservice music therapists and preservice music teachers may experience extreme increases in vocal load when they enter the field. Absent training protocols, these increases could be detrimental to their vocal health and long-term viability as practitioners.

Noise, Age, and Gender Effects on Speech Intelligibility and Sentence Comprehension for 11- to 13-Year-Old Children in Real Classrooms

The present study aimed to investigate the effects of type of noise, age, and gender on children’s speech intelligibility (SI) and sentence comprehension (SC). The experiment was conducted with 171 children between 11 and 13 years old in ecologically-valid conditions (collective presentation in real, reverberating classrooms). Two standardized tests were used to assess SI and SC. The two tasks were presented in three listening conditions: quiet; traffic noise; and classroom noise (non-intelligible noise with the same spectrum and temporal envelope of speech, plus typical classroom sound events). Both task performance accuracy and listening effort were considered in the analyses, the latter tracked by recording the response time (RT) using a single-task paradigm. Classroom noise was found to have the worst effect on both tasks (worsening task performance accuracy and slowing RTs), due to its spectro-temporal characteristics. A developmental effect was seen in the range of ages (11–13 years), which depended on the task and listening condition. Gender effects were also seen in both tasks, girls being more accurate and quicker to respond in most listening conditions. A significant interaction emerged between type of noise, age and task, indicating that classroom noise had a greater impact on RTs for SI than for SC. Overall, these results indicate that, for 11- to 13-year-old children, performance in SI and SC tasks is influenced by aspects relating to both the sound environment and the listener (age, gender). The presence of significant interactions between these factors and the type of task suggests that the acoustic conditions that guarantee optimal SI might not be equally adequate for SC. Our findings have implications for the development of standard requirements for the acoustic design of classrooms.

Impact of Nonmodal Phonation on Estimates of Subglottal Pressure From Neck-Surface Acceleration in Healthy Speakers

Purpose The purpose of this study was to evaluate the effects of nonmodal phonation on estimates of subglottal pressure (Ps) derived from the magnitude of a neck-surface accelerometer (ACC) signal and to confirm previous findings regarding the impact of vowel contexts and pitch levels in a larger cohort of participants. Method Twenty-six vocally healthy participants (18 women, 8 men) were asked to produce a series of p-vowel syllables with descending loudness in 3 vowel contexts (/a/, /i/, and /u/), 3 pitch levels (comfortable, high, and low), and 4 elicited phonatory conditions (modal, breathy, strained, and rough). Estimates of Ps for each vowel segment were obtained by averaging the intraoral air pressure plateau before and after each segment. The root-mean-square magnitude of the neck-surface ACC signal was computed for each vowel segment. Three linear mixed-effects models were used to statistically assess the effects of vowel, pitch, and phonatory condition on the linear relationship (slope and intercept) between Ps and ACC signal magnitude. Results Results demonstrated statistically significant linear relationships between ACC signal magnitude and Ps within participants but with increased intercepts for the nonmodal phonatory conditions; slopes were affected to a lesser extent. Vowel and pitch contexts did not significantly affect the linear relationship between ACC signal magnitude and Ps. Conclusion The classic linear relationship between ACC signal magnitude and Ps is significantly affected when nonmodal phonation is produced by a speaker. Future work is warranted to further characterize nonmodal phonatory characteristics to improve the ACC-based prediction of Ps during naturalistic speech production.

A Healthy, Energy-Efficient and Comfortable Indoor Environment, a Review

Design strategies for sustainable buildings, that improve building performance and avoid extensive resource utilization, should also promote healthy indoor environments. The following paper contains a review of the couplings between (1) building design, (2) indoor environmental quality and (3) occupant behavior. The paper focuses on defining the limits of adaptation on the three aforementioned levels to ensure the energy efficiency of the whole system and healthy environments. The adaptation limits are described for measurable physical parameters and the relevant responsible human sensory systems, evaluating thermal comfort, visual comfort, indoor air quality and acoustical quality. The goal is to describe the interactions between the three levels where none is a passive participant, but rather an active agent of a wider human-built environment system. The conclusions are drawn in regard to the comfort of the occupant. The study reviews more than 300 sources, ranging from journals, books, conference proceedings, and reports complemented by a review of standards and directives.

Speech level parameters in very low and excessive reverberation measured with a contact-sensor-based device and a headworn microphone

This work deals with the effect of very low and excessive reverberation on speech sound pressure levels. Measurements were carried out in a semi-anechoic and reverberant room using a contact-sensor-based device fixed at the base of the neck and a headworn microphone placed at 2.5 cm from the speaker's mouth. Speakers produced short monologues and also described a map with the intent of correctly explaining directions to a listener 6 m away. A significant increase of about 2 dB in mean, equivalent, and mode speech levels in semi-anechoic compared to reverberant room was on average observed for the map description from recordings with the contact device, thus, highlighting an increased vocal intensity in dead rooms when the speech task had a communicative intent. Such reliable results were not found with the headworn microphone because speech levels were affected by noise recorded in the pauses. Particularly, the 30 ms logging interval brought to more severe errors in mode and mean speech levels compared to 1 s. When the pauses were removed and a logging interval of 30 ms was adopted, results were more consistent with those obtained with the contact sensor, but level differences between the two rooms still remained not significant.

Assessing the Acoustic Characteristics of Rooms: A Tutorial with Examples

In both practicing audiology and speech language pathology, as well as in speech and hearing science research, the space where the work is done is an integral part of the function. Hence, for all of these endeavors it can be important to measure the acoustics of a room. This article provides a tutorial regarding the measurement of room reverberation and background noise, both of which are important when evaluating a space's strengths and limitations for speech communication. As the privacy of patients and research participants is a primary concern, the tutorial also describes a method for measuring the amount of acoustical insulation provided by a room's barriers. Several room measurement data sets - all obtained from the assessment of clinical and research spaces within our own department - are presented here as examples.

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.

Influence of Noise Resulting From the Location and Conditions of Classrooms and Schools in Upper Egypt on Teachers' Voices

PURPOSE

Teachers are professional voice users, always at high risk of developing voice disorders due to high vocal demand and unfavorable environmental conditions. This study aimed at identifying possible correlations between teachers' voice symptoms and their perception of noise, the location of schools, as well as the location and conditions of their classrooms.

METHOD

One hundred forty teachers (ages 21-56) from schools in Upper Egypt participated in this study. They filled out a questionnaire including questions about the severity and frequency of their voice symptoms, noise perception, and the location and conditions of their schools and classrooms. Questionnaire responses were statistically analyzed to identify possible correlations.

RESULTS

There were significant correlations (P < 0.05) between voice symptoms, teachers' noise perception, and noise resulting from the location and conditions of schools and classrooms. Teachers experienced severe dysphonia, neck pain, and increased vocal effort with weekly or daily recurrence. Among the teachers who participated in the study, 24.2% felt they were always in a noisy environment, with 51.4% of the total participants reporting having to raise their voices. The most common sources of noise were from student activities and talking in the teachers' own classrooms (61.4%), noise from adjacent classrooms (52.9%), and road traffic (40.7%).

CONCLUSIONS

Adverse effect on teachers' voices due to noise from poor school and classroom conditions necessitates solutions for the future improvement of conditions in Egyptian schools. This study may help future studies that focus on developing guidelines for the better planning of Egyptian schools in terms of improved infrastructure and architecture, thus considering the general and vocal health of teachers.

Accuracy of the quantities measured by four vocal dosimeters and its uncertainty

Although vocal dosimeters are often used for long-term voice monitoring, the uncertainty of the quantities measured by these devices is not always stated. In this study, two common vocal dosimetry quantities, mean vocal sound pressure level and mean vocal fundamental frequency, were measured by four vocal dosimeters (VocaLog2, VoxLog, Voice Care, and APM3200). The expanded uncertainty of the mean error in the estimation of these two quantities as measured by the four dosimeters was performed by simultaneously comparing signals acquired through a reference microphone and the devices themselves. Dosimeters, assigned in random order, were worn by the participants (22 vocally healthy adults), along with a head-mounted microphone, which acted as a reference. For each device, participants produced a sustained /a/ vowel four times and then read a text with three different vocal efforts (relaxed, normal, and raised). The measurement uncertainty was obtained by comparing data from the microphone and the dosimeters. The mean vocal sound pressure level was captured the most accurately by the Voice Care and the VoxLog while the APM3200 was the least accurate. The most accurate mean vocal fundamental frequency was estimated by the Voice Care and the APM3200, while the VoxLog was the least accurate.

The Effect of Classroom Capacity on Vocal Fatigue as Quantified by the Vocal Fatigue Index

OBJECTIVE

Previous research has concluded that teachers are at a higher-than-normal risk for voice issues that can cause occupational limitations. While some risk factors have been identified, there are still many unknowns.

PATIENTS AND METHODS

A survey was distributed electronically with 506 female teacher respondents. The survey included questions to quantify three aspects of vocal fatigue as captured by the Vocal Fatigue Index (VFI): (1) general tiredness of voice (performance), (2) physical discomfort associated with voicing (pain), and (3) improvement of symptoms with rest (recovery). The effect of classroom capacity on US teachers' self-reported experience of vocal fatigue was analyzed.

RESULTS

The results indicated that a classroom's capacity significantly affected teachers' reported amounts of vocal fatigue, while a teacher's age also appeared to significantly affect the reported amount of vocal fatigue. A quadratic rather than linear effect was seen, with the largest age effect occurring at around 40-45 years in all three factors of the VFI.

CONCLUSION

Further factors which may affect vocal fatigue must be explored in future research. By understanding what increases the risk for vocal fatigue, educators and school administrators can take precautions to mitigate the occupational risk of short- and long-term vocal health issues in school teachers.

A one-school year longitudinal study of secondary school teachers' voice parameters and the influence of classroom acoustics

Recent literature reports that a large percentage of teachers complain that teaching has an adverse effect on their voice status. Thus, more needs to be done to study their vocal behavior. The objective of this longitudinal study was twofold: to determine changes in the voice use of teachers over a school year, and to study the relationships between voice use and classroom acoustic parameters. Thirty-one teachers from two secondary schools in Turin (Italy) were involved at the beginning of the 2014-2015 school year, and 22 of them also participated at the end of the same school year. The results show that teachers adjust their voices with noise and reverberation. A minimum value of the sound pressure level of voice (SPL) was found at a mid-frequency reverberation time of 0.8 s in both periods. Moreover, the teachers who worked in the worst classroom acoustic conditions showed an increase of 2.3 dB in the mean SPL and a decrease of 10% in the voicing time percentage at the end of the school year. A predictive model that can be used to estimate the mean SPL from the background noise level and the reverberation time, based on collected data, is here proposed.

Intra-speaker and inter-speaker variability in speech sound pressure level across repeated readings

The intra- and inter-speaker variability of speech sound pressure level (SPL) has been investigated under repeatability conditions in this work. In a semi-anechoic chamber, speech from 17 individuals was recorded with a sound level meter, a headworn microphone, and a vocal monitoring device. The subjects were asked to read twice and in sequence two phonetically balanced passages. The speech variability has been investigated for mean, equivalent, and mode SPL from each reading and device. The intra-speaker variability has been evaluated by means of the average among individual standard deviations in the four readings and it reached the maximum of 2 dB for mode SPL. For the inter-speaker variability, the experimental standard deviation of individual averaged SPL parameters among the four repeated measures has been calculated, obtaining the highest value of 5.3 dB for mode SPL. Changes in SPL variability have been evaluated with different logging intervals for each device. The influence of speech material has been investigated by the Wilcoxon test on paired lists of descriptive statistics for SPL distribution and equivalent SPL in the repeated readings. The data reported in this study may be considered as a preliminary reference for the investigation of changes in speech SPL over subjects.

Analysing the vocal behaviour of teachers during classroom teaching using a portable voice accumulator

PURPOSE

Teachers are at a considerable risk of developing vocal health problems due to intensive voice use during teaching. This study investigated factors related to the teacher's voice during a teaching situation.

METHODS

Overall, 113 teachers were recorded during a typical class lesson, lasting on average 48 min. A portable voice dosimeter (VoxLog System) was used to measure the sound pressure level (SPL) of the noise in the classroom, the teacher's voice SPL, the fundamental frequency (f_o) and the phonation time. General conditions of each lesson such as number of pupils, lesson subject and the educational level of the class were also collected. For the analysis, vocal loading doses and correlations between teacher's voice and noise SPL were calculated.

RESULTS

Voice and noise SPL values varied across the lesson subjects, with highest levels measured in sports lessons. The mean noise SPL changed throughout a lesson with highest values at the beginning and at the end of the lessons. The correlation analysis of voice and noise SPL identified two groups of teachers with different vocal SPL behaviours. For some teachers, the voice SPL varied with the noise SPL. For others, voice SPL was constantly high. A regression model on the teacher's voice SPL yielded a strong correlation with f_o, the classroom noise SPL, and the individual vocal SPL behaviour.

CONCLUSIONS

Classroom noise SPL and individual vocal SPL behaviour were significantly associated with teachers' voice SPL during teaching. Addressing these factors could be important steps in reducing the vocal load in teachers.

Evaluation of the starting point of the Lombard Effect

Speakers increase their vocal effort when their communication is disturbed by noise. This adaptation is termed the Lombard effect. The aim of the present study was to determine whether this effect has a starting point. Hence, the effects of noise at levels between 20 and 65 dB(A) on vocal effort (quantified by sound pressure level) and on both perceived noise disturbance and perceived vocal discomfort were evaluated. Results indicate that there is a Lombard effect change-point at a background noise level (Ln) of 43.3 dB(A). This change-point is anticipated by noise disturbance, and is followed by a high magnitude of vocal discomfort.

Four-day-follow-up study on the voice monitoring of primary school teachers: Relationships with conversational task and classroom acoustics

The present study has investigated the occupational voice use of 27 female primary school teachers over a four-day-follow-up. Sixty-one working-day voice samples were acquired with two contact sensor-based vocal analyzers in four schools with highly different classroom acoustics. The vocal parameters were compared with a conversational task that the teachers performed before each lesson and with the measured classroom acoustic parameters. The average equivalent sound pressure level at 1 m from the mouth, which refers to the teacher's vocal effort, and the voicing time percentage were 71.2 dB [standard error (SE) 1.0 dB] and 29%, respectively. The teachers' mean voice level and fundamental frequency were significantly higher in the occupational setting than in the conversational one, which is by 5.5 dB (SE 0.5 dB) and 50 Hz (SE 3 Hz), respectively. Higher voice levels were observed for higher background noise levels, at a rate of 0.53 dB/dB, and a tendency of the background noise to increase with increasing reverberation time was observed at a rate of 13 dB/s. An optimal reverberation time of 0.7 s was found to minimize the voice level, since teachers raised their voice at lower and higher reverberation times, the latter presumably due to higher background noise levels.

Teachers' voicing and silence periods during continuous speech in classrooms with different reverberation times

The relationship between reverberation times and the voicing and silence accumulations of continuous speech was quantified in 22 primary-school teachers. Teachers were divided into a high and a low reverberation time groups based on their classroom reverberation time (higher and lower than 0.90 s). Reverberation times higher than 0.90 s implicate higher voicing accumulations and higher accumulations of the silences typical of turn taking in dialogue. These results suggest that vocal load, which can lead to vocal fatigue, is influenced by classroom reverberation time. Therefore, it may be considered a risk factor for occupational voice users.

Combined effect of noise and room acoustics on vocal effort in simulated classrooms

This work investigated the relationships between room acoustics, background noise level, and vocal effort of a speaker in simulated classrooms of various volumes. Under simulated acoustic environments, talkers adjusted their vocal effort linearly with the voice support, i.e., the degree of amplification offered by the room to the voice of a speaker, at his own ears. The slope of this relationship, called the room effect, of -0.24 dB/dB was significant only in the case of the highest noise levels of 62 dB. The vocal comfort for the speaker, however, was found to be more closely related to noise annoyance than to room reverberance.

Assessments of Voice Use and Voice Quality Among College/University Singing Students Ages 18-24 Through Ambulatory Monitoring With a Full Accelerometer Signal

The multiple social and performance demands placed on college/university singers could put their still-developing voices at risk. Previous ambulatory monitoring studies have analyzed the duration, intensity, and frequency (in Hertz) of voice use among such students. Nevertheless, no studies to date have incorporated the simultaneous acoustic voice quality measures into the acquisition of these measures to allow for direct comparison during the same voicing period. Such data could provide greater insight into how young singers use their voices, as well as identify potential correlations between vocal dose and acoustic changes in voice quality. The purpose of this study was to assess the voice use and the estimated voice quality of college/university singing students (18-24 years old, N = 19). Ambulatory monitoring was conducted over three full, consecutive weekdays measuring voice from an unprocessed accelerometer signal measured at the neck. From this signal, traditional vocal dose metrics such as phonation percentage, dose time, cycle dose, and distance dose were analyzed. Additional acoustic measures included perceived pitch, pitch strength, long-term average spectrum slope, alpha ratio, dB sound pressure level 1-3 kHz, and harmonic-to-noise ratio. Major findings from more than 800 hours of recording indicated that among these students (a) higher vocal doses correlated significantly with greater voice intensity, more vocal clarity and less perturbation; and (b) there were significant differences in some acoustic voice quality metrics between nonsinging, solo singing, and choral singing.

Estimating Subglottal Pressure From Neck-Surface Acceleration During Normal Voice Production

Purpose

The purpose of this study was to evaluate the potential for estimating subglottal air pressure using a neck-surface accelerometer and to compare the accuracy of predicting subglottal air pressure relative to predicting acoustic sound pressure level (SPL).

Method

Indirect estimates of subglottal pressure (Psg') were obtained from 10 vocally healthy speakers during loud-to-soft repetitions of 3 different /p/-vowel gestures (/pa/, /pi/, /pu/) at 3 pitch levels in the modal register. Intraoral air pressure, neck-surface acceleration, and radiated acoustic pressure were recorded, and the root-mean-square amplitude of the acceleration signal was correlated with Psg' and SPL.

Results

The coefficient of determination between accelerometer level and Psg' was high when data were pooled from all vowel and pitch contexts for each participant (r2 = .68-.93). These relationships were stronger than corresponding relationships between accelerometer level and SPL (r2 = .46-.81). The average 95% prediction interval for estimating Psg' using accelerometer level was ±2.53 cm H2O, ranging from ±1.70 to ±3.74 cm H2O across participants.

Conclusions

Accelerometer signal amplitude correlated more strongly with Psg' than with SPL. Future work is warranted to investigate the robustness of the relationship in nonmodal voice qualities, individuals with voice disorders, and accelerometer-based ambulatory monitoring of subglottal pressure.

Four-day Follow-up Study on the Self-reported Voice Condition and Noise Condition of Teachers: Relationship Between Vocal Parameters and Classroom Acoustics

OBJECTIVES

This study aimed to determine the changes in self-reported voice and noise condition over a follow-up of 4 days (equivalent to one working week), to define the relationship between the objective voice parameters and the self-reported voice condition, as well as to characterize the relationship between classroom acoustics and the self-reported noise condition.

STUDY DESIGN

This is a cohort study.

METHODS

We performed voice monitoring of 27 teachers for four working days using the Voice-Care device, which provides information on the fundamental frequency, vocal sound pressure level, and phonation time percentage. The participants performed a pre-monitoring, which consisted of a brief conversation, before each monitoring session, and filled in a questionnaire after each monitored lesson, in which they indicated their opinions about their voice condition and the classroom noise conditions.

RESULTS

The teachers who, during the pre-monitoring, showed a higher standard deviation of the vocal sound pressure level and a greater phonation time percentage difference between the entire monitoring and the pre-monitoring sessions, reported fewer voice complaints. Decay time (DT_40ME), a reverberation measure from the speakers' perspective, resulted to be associated with the self-reporting of the noise condition.

CONCLUSION

Voice disorders at work prevention programs should include strategies to exercise the respiratory and laryngeal components of voice production, because these elements may influence the variation in the vocal sound pressure level, which was found to be significantly associated with the self-reported voice condition. This study also highlights the importance of including reverberation measures, from the speakers' perspective, in the design of schools.

Silence and Voicing Accumulations in Italian Primary School Teachers With and Without Voice Disorders

OBJECTIVES

The relationship between the silence and voicing accumulations of primary school teachers and the teachers' clinical status was examined to determine whether more voicing accumulations and fewer silence accumulations were measured for the vocally unhealthy subjects than for the healthy subjects, which would imply more vocal loading and fewer short-term recovery moments.

METHODS

Twenty-six Italian primary school teachers were allocated by clinicians to three groups: (1) with organic voice disorders, (2) with subjectively mild organic alteration or functional voice symptoms, and (3) normal voice quality and physiology. Continuous silence and voicing periods were measured with the APM3200 during the teachers' 4-hour workdays. The accumulations were grouped into seven time intervals, ranging from 0.03-0.9 to 3.16-10 seconds, according to Italian prosody. The effects of group on silence and voicing accumulations were evaluated.

RESULTS

Regarding silence accumulations, Group 1 accumulated higher values in intervals between 0.1 and 3.15 seconds than other groups, whereas Groups 2 and 3 did not differ from each other. Voicing accumulations between 0.17 and 3.15 seconds were higher for subjects with a structural disorder. A higher time dose was accumulated by these subjects (40.6%) than other subjects (Group 2, 31.9%; Group 3, 32.3%).

CONCLUSIONS

Although previous research has suggested that a rest period of a few seconds may produce some vocal fatigue recovery, these results indicate that periods shorter than 3.16 seconds may not have an observable effect on recovery. The results provide insight into how vocal fatigue and vocal recovery may relate to voice disorders in occupational voice users.

Effects of speech style, room acoustics, and vocal fatigue on vocal effort

Vocal effort is a physiological measure that accounts for changes in voice production as vocal loading increases. It has been quantified in terms of sound pressure level (SPL). This study investigates how vocal effort is affected by speaking style, room acoustics, and short-term vocal fatigue. Twenty subjects were recorded while reading a text at normal and loud volumes in anechoic, semi-reverberant, and reverberant rooms in the presence of classroom babble noise. The acoustics in each environment were modified by creating a strong first reflection in the talker position. After each task, the subjects answered questions addressing their perception of the vocal effort, comfort, control, and clarity of their own voice. Variation in SPL for each subject was measured per task. It was found that SPL and self-reported effort increased in the loud style and decreased when the reflective panels were present and when reverberation time increased. Self-reported comfort and control decreased in the loud style, while self-reported clarity increased when panels were present. The lowest magnitude of vocal fatigue was experienced in the semi-reverberant room. The results indicate that early reflections may be used to reduce vocal effort without modifying reverberation time.

Effects of voice style, noise level, and acoustic feedback on objective and subjective voice evaluations

Speakers adjust their vocal effort when communicating in different room acoustic and noise conditions and when instructed to speak at different volumes. The present paper reports on the effects of voice style, noise level, and acoustic feedback on vocal effort, evaluated as sound pressure level, and self-reported vocal fatigue, comfort, and control. Speakers increased their level in the presence of babble and when instructed to talk in a loud style, and lowered it when acoustic feedback was increased and when talking in a soft style. Self-reported responses indicated a preference for the normal style without babble noise.