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

Quantifying Vocal Repertoire Tessituras Through Real-Time Measures

INTRODUCTION

Voice teachers use anecdotal evidence and experience in determining the appropriateness of repertoire for each student's development. Tessitura is important in that determination, but until recently a straightforward, repeatable, and quantifiable method for determining tessitura has not existed. However, technology exists to provide the means to estimate the tessituras of standard vocal repertoire by measuring sung pitch (fundamental frequency) and vocal dose (amount of phonation) in real-time performance.

PURPOSE

The purpose of this study was to examine the combined use of tessituragrams, Voice Range Profiles (VRPs), a singer's self-perception of a performance, and expert listeners perception of a performance towards the goal of a more systematic way of selecting appropriate voice repertoire for singers. The following research questions guided this investigation: 1) How do Performance Range Profiles (PRPs, performance-based tessituragrams computed from neck skin surface vibration during singing), compare to score-based tessituragrams of the same selection in the same key? 2) How do PRPs of the same vocal score compare when performed in three different keys? 3) How do singer VRPs compare with PRPs of three performances of a score, each sung in a different key? and 4) How do singer and expert panel perceptions of the selection's "fit" in three different keys compare with the alignment of each singer's VRP to their PRPs? Four female singers and five expert voice pedagogues were enlisted to address these questions.

RESULTS

The distribution (histogram) of the score-based tessituragram closely matched the distribution of performance-based tessituragrams (PRP), suggesting that score-based tessituragrams have promise in accurately reflecting the performance-based tessitura of a musical vocal work. Acquired data revealed relationships of practical importance between score-derived tessituragrams, PRPs, acquired VRPs, and singer perceptions of ease in singing. These data suggest that score-based tessituragrams aligned with singer VRPs show promise in repertoire selection. However, there was only a minor relationship between expert panel perceptions of ease in singing and the acquired PRPs or singer perceptions of ease. Creation of a score-based tessituragram database could be combined with singer VRPs to assist in appropriate repertoire selection.

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.

Factors Influencing Teachers' Experience of Vocal Fatigue and Classroom Voice Amplification

BACKGROUND

Voice disorders among teachers are widespread. Teachers' voice problems have been shown to influence the teaching-learning process, thereby impeding students' academic performance. Voice amplification has been used as a preventative strategy to avoid voice problems and as a means of augmenting student reception of a teacher's voice. However, the relationship between perceived vocal fatigue and amplification use has not been established, nor have factors been identified which may be associated with the use of voice amplification in the classroom.

PURPOSE

This research has two aims: (1) determine the relationship between self-reported vocal fatigue and self-reported teachers' use of sound field amplification in the classroom; and (2) identify which factors are related with the use of amplification systems among the participating teachers.

METHODS

Paper and online surveys were provided to teachers throughout the United States. These surveys contained the 19-question Vocal Fatigue Index (VFI), in addition to other questions regarding health-related conditions and lifestyle habits of respondents. Access to and use of amplification systems, as well as other work-related factors that might influence the use of such systems were detailed by the respondents.

RESULTS

Regardless of grades levels or measured factors, teachers who reported using amplification systems were more likely to report higher levels of vocal fatigue. Teachers who taught in lower grade levels or in larger capacity classrooms not only reported a greater likelihood of using the systems more frequently, but also reported a greater access to amplification systems. Overall, less than 40% of teachers had access to an amplification system. Teachers of lower grades reported having the least access.

CONCLUSIONS

Our results suggest an association between teachers' use of voice amplification systems and vocal fatigue. In addition, some work-related factors (eg, grade level, classroom capacity) were associated with the use of amplification systems. The results can be beneficial to teachers, school administrators, lawmakers and health professionals to more efficiently use diminishing educational resources in a targeted fashion to better train and potentially reduce the occurrence of voice problems among teachers.

Kalman Filter Implementation of Subglottal Impedance-Based Inverse Filtering to Estimate Glottal Airflow during Phonation

Subglottal Impedance-Based Inverse Filtering (IBIF) allows for the continuous, non-invasive estimation of glottal airflow from a surface accelerometer placed over the anterior neck skin below the larynx. It has been shown to be advantageous for the ambulatory monitoring of vocal function, specifically in the use of high-order statistics to understand long-term vocal behavior. However, during long-term ambulatory recordings over several days, conditions may drift from the laboratory environment where the IBIF parameters were initially estimated due to sensor positioning, skin attachment, or temperature, among other factors. Observation uncertainties and model mismatch may result in significant deviations in the glottal airflow estimates; unfortunately, they are very difficult to quantify in ambulatory conditions due to a lack of a reference signal. To address this issue, we propose a Kalman filter implementation of the IBIF filter, which allows for both estimating the model uncertainty and adapting the airflow estimates to correct for signal deviations. One-way analysis of variance (ANOVA) results from laboratory experiments using the Rainbow Passage indicate an improvement using the modified Kalman filter on amplitude-based measures for phonotraumatic vocal hyperfunction (PVH) subjects compared to the standard IBIF; the latter showing a statistically difference (p-value = 0.02, F = 4.1) with respect to a reference glottal volume velocity signal estimated from a single notch filter used here as ground-truth in this work. In contrast, maximum flow declination rates from subjects with vocal phonotrauma exhibit a small but statistically difference between the ground-truth signal and the modified Kalman filter when using one-way ANOVA (p-value = 0.04, F = 3.3). Other measures did not have significant differences with either the modified Kalman filter or IBIF compared to ground-truth, with the exception of H1–H2, whose performance deteriorates for both methods. Overall, both methods (modified Kalman filter and IBIF) show similar glottal airflow measures, with the advantage of the modified Kalman filter to improve amplitude estimation. Moreover, Kalman filter deviations from the IBIF output airflow might suggest a better representation of some fine details in the ground-truth glottal airflow signal. Other applications may take more advantage from the adaptation offered by the modified Kalman filter implementation.

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.

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.

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.

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.

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.

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.

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.