Vocal loading among day care center teachers

Developing Educational Health Modules to Improve Vocal Wellness in Mask-Wearing Occupational Voice Users

OBJECTIVE

To develop educational modules to improve vocal wellness and optimize communication in mask-wearing occupational voice users.

METHODS

Module development focused on identifying accurate, understandable, and actionable steps to improve vocal wellness in the workplace. We i) interviewed eight voice-specialized speech-language pathologists and researchers on current speech and voice recommendations for mask-wearers, ii) developed educational content using the standardized Patient Education Materials Assessment Tool (PEMAT), iii) assessed the ability of nine mask-wearing community members to learn educational content, and iv) compared behavioral, acoustical, and perceptual changes in four mask-wearing healthcare professionals following educational training.

RESULTS

We created three educational modules that described key vocal health and communication strategies, including microphone amplification, postural alignment, clear speech, hydration, vocal naps, and vocal warm-ups. PEMAT scores were 96% and 93% on understandability and actionability, respectively. Mask-wearing healthcare professionals increased use of 4 out of the 6 strategies following educational training and were able to retain information at rates >90% at 1-week follow-up.

CONCLUSIONS

We developed a set of free-to-use educational modules to promote vocal wellness among mask-wearing occupational voice users (see VSMechLab.com). Future work should examine the impact of these strategies on voice measures in a larger group of mask-wearing community members.

Maternal occupational noise exposure during pregnancy and children's early language acquisition

INTRODUCTION

Noise exposure during pregnancy may affect a child's auditory system, which may disturb fetal learning and language development. We examined the impact of occupational noise exposure during pregnancy on children's language acquisition at the age of one.

METHODS

A cohort study was conducted among women working in the food industry, as kindergarten teachers, musicians, dental nurses, or pharmacists who had a child aged <1 year. The analyses covered 408 mother-child pairs. Language acquisition was measured using the Infant-Toddler Checklist. An occupational hygienist assessed noise exposure individually as no (N = 180), low (70-78 dB; N = 108) or moderate/high exposure (>79 dB; N = 120).

RESULTS

Among the boys, the adjusted mean differences in language acquisition scores were -0.4 (95% CI -2.5, 1.8) for low, and -0.7 (95% CI -2.9, 1.4) for moderate/high exposure compared to no exposure. Among the girls the respective scores were +0.1 (95% CI -2.2, 2.5) and -0.1 (95% CI -2.3, 2.2). Among the children of kindergarten teachers, who were mainly exposed to human noise, low or moderate exposure was associated with lower language acquisition scores. The adjusted mean differences were -3.8 (95% CI -7.2, -0.4) for low and -4.9 (95% CI -8.6, -1.2) for moderate exposure.

CONCLUSIONS

In general, we did not detect an association between maternal noise exposure and children's language acquisition among one-year-old children. However, the children of kindergarten teachers exposed to human noise had lower language acquisition scores than the children of the non-exposed participants. These suggestive findings merit further investigation by level and type of exposure.

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.

Work-Related Vocal Challenges of Online Teaching: A Study of Female College Professors

BACKGROUND

College professors are at an elevated risk of developing voice disorders due to increased vocal demands associated with their working conditions, including high background noise levels, long reverberation times, prolonged voice use duration, and large class sizes. However, the impact of online classes on vocal health among college professors remains unclear.

OBJECTIVE

This longitudinal study aimed to characterize voice changes associated with online teaching among female Colombian college professors.

METHODS

Thirteen female college professors teaching online classes completed an online survey that included questions about voice functioning, working conditions, the Spanish translation of the Vocal Fatigue Index (VFI), and the Spanish translation of the Voice-Related Quality of Life. Instrumental measurements were also performed, including environmental background noise levels, hearing screening, and voice recordings before and after a synchronous online class.

RESULTS

This study found a decreased fundamental frequency in connected speech (reading) associated with the number of students per class, the number of classes per week, and background noise levels measured with a sound level meter. L1L0 was statistically smaller among experienced teachers with higher background noise levels compared with less-experienced colleagues in quieter classes. 1558kHz was statistically associated with the average number of students, whereas HNR was slightly higher for professors with more students and more classes per week.

CONCLUSION

The findings suggest that online teaching has important implications for voice production among participating teachers. This study highlights the importance of considering working conditions during online classes when designing workplace prevention programs for college professors.

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.

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.

Vocal fatigue in professors at the beginning and end of the school year

PURPOSE

To characterize and to compare the perception of vocal fatigue in professors at the beginning and at the end of the school year.

METHODS

Observational, analytical, prospective cohort study was carried out. A total of 115 professors participated with a mean age of 40 years old, 71 women and 44 men, employees of 28 higher education institutions in the south and southeast regions of Brazil. All answered to the Vocal Fatigue Index (VFI) at the beginning (February or March) and at the end (October or November) of the Brazilian school year. The VFI results for both assessed moments were statistically compared (p<0.05).

RESULTS

The professors' mean scores obtained in the factors of tiredness of voice and avoidance of voice use (p<0.001) and improvement of symptoms with rest (p=0.001) increased at the end of the school year.

CONCLUSION

Professors reported higher perception of vocal fatigue at the end of the school year, which influenced the avoidance of voice use and improvement of symptoms with the rest.

Teachers' and Children's Experiences after an Acoustic Intervention and a Noise-Controlling Workshop in Two Elementary Classrooms

INTRODUCTION

Treating sources of noise is a novel aspect of voice ergonomics intended to enhance the preconditions for good voice production and easy listening.

OBJECTIVE

To improve experiences of listening and voice ergonomics in classrooms.

METHODS

Participants were two female elementary school teachers with voice symptoms and their pupils (n = 50). Two interventions were performed: the acoustic intervention and then the workshop intervention where the teachers and pupils were active. Teachers' voice symptoms and pupils' and teachers' experiences of the interventions were elicited by questionnaire.

RESULTS

The teacher with many voice symptoms experienced more annoyance from sounds and benefitted more from the interventions. After the interventions both teachers suffered fewer voice breaks and voice symptoms such as lump and mucus in the throat. The pupils reported improvement in the teachers' voice clarity and audibility (p = 0.001). Pupils aged 12-13 years were more annoyed by sounds than those aged 8-9 years (p = 0.003). The older pupils experienced less sound annoyance after both interventions and the younger ones after the workshop intervention.

CONCLUSIONS

The importance of good acoustics and individuals' ability to improve voice ergonomics and listening conditions was demonstrated.

The Others Are Too Loud! Children's Experiences and Thoughts Related to Voice, Noise, and Communication in Nordic Preschools

BACKGROUND

High noise levels affect hearing, voice use, and communication. Several studies have reported high noise levels in preschools and impaired voice quality in children. Noise and poor listening conditions impair speech comprehension in children more than in adults and even more for children with hearing or language impairment, attention deficits, or another first language.

AIM

The aim of this study was to explore how children in Finland, Sweden, and Iceland describe the preschool environment in relation to noise, voice, and verbal communication; what were their experiences, knowledge and ideas in relation to voice, noise, and communication. Children's awareness of effects of noise, reactions, and coping strategies were also studied. In addition, country and gender differences were analyzed.

METHODS

Eighteen Icelandic, 14 Finnish, and 16 Swedish children were interviewed using a common interview-guide. Swedish and Finnish children were interviewed in focus groups and Icelandic children individually. All interviews were transcribed verbatim and analyzed thematically by the native speaker. The interviews were translated to English to be re-analyzed for inter-judge reliability of identified themes. Inter-judge reliability was calculated using percentage absolute agreement.

RESULTS

The interviews resulted in 1052 utterances, 471 from focus groups, and 581 from individual interviews. Three themes were identified, Experiences, Environment, and Strategies with two to three subcategories. Inter-judge agreement for the themes was excellent, 92-98%. Experiences occurred in 55% of the utterances. The subcategories were bodily and emotional experiences and experiences of hearing and being heard. Environment occurred in 20% of the utterances, with subcategories indoor vs. outdoor and noise. Strategies was found in 15%, with subcategories games and problem oriented actions. The only significant difference between the countries was for the theme Strategies where the Swedish children produced more utterances than the Finnish. No gender differences were found.

CONCLUSION

Children are aware of high noise levels and mainly blame other children for making noise and shouting. They describe reactions and strategies related to noise like impaired communication and effects on hearing but are less aware of effects on voice. Expressed thoughts were similar across countries. No gender differences were found.

The Importance of The Occupational Vocal Load for The Occurence and Treatment of Organic Voice Disorders

Introduction

The voice represents a basic working tool for carrying out certain occupations. Hoarseness, as a consequence of vocal fold lesions, presents an important cause of work-related absences for voice professionals.

Methods

Our study was designed as a retrospective cohort one. Data on gender, workplace, vocal load and exposure to risk factors for voice disorders of the patients who had surgery in the 2014-2015 period at the tertiary centre due to benign vocal fold lesions were collected from their clinical records. We compared professional voice users (PVU) to subjects with no vocal load at work (NPVU). The SPSS programme, version 22.0, was used for statistical analysis.

Results

From 2014 to 2015, 103 PVU and 132 NPVU were surgically treated for benign vocal fold lesions. In comparison to the second group, loud speech use was reported significantly more often by PVU (40.8% vs. 14.4%), as was a fast speaking rate (22.3% vs. 9.8%) and additional vocal load outside of the workplace (23.3% vs. 12.9%). The time that had passed between the occurrence of the hoarseness and the surgical treatment did not differ between the groups. The majority of patients were satisfied with the outcome of the operation.

Conclusions

Nearly a half of the operated patients had a considerable vocal load at work. An ENT assessment prior to starting a job as well as priority phoniatric treatment of voice disorders for PVU would significantly reduce the costs of work absences and contribute to a speedier recovery and return to the workplace.

The importance of the occupational vocal load for the occurence and treatment of organic voice disorders

Introduction

The voice represents a basic working tool for carrying out certain occupations. Hoarseness, as a consequence of vocal fold lesions, presents an important cause of work-related absences for voice professionals.

Methods

Our study was designed as a retrospective cohort one. Data on gender, workplace, vocal load and exposure to risk factors for voice disorders of the patients who had surgery in the 2014-2015 period at the tertiary centre due to benign vocal fold lesions were collected from their clinical records. We compared professional voice users (PVU) to subjects with no vocal load at work (NPVU). The SPSS programme, version 22.0, was used for statistical analysis.

Results

From 2014 to 2015, 103 PVU and 132 NPVU were surgically treated for benign vocal fold lesions. In comparison to the second group, loud speech use was reported significantly more often by PVU (40.8% vs. 14.4%), as was a fast speaking rate (22.3% vs. 9.8%) and additional vocal load outside of the workplace (23.3% vs. 12.9%). The time that had passed between the occurrence of the hoarseness and the surgical treatment did not differ between the groups. The majority of patients were satisfied with the outcome of the operation.

Conclusions

Nearly a half of the operated patients had a considerable vocal load at work. An ENT assessment prior to starting a job as well as priority phoniatric treatment of voice disorders for PVU would significantly reduce the costs of work absences and contribute to a speedier recovery and return to the workplace.

Accuracy of Self-Reported Estimates of Daily Voice Use in Adults With Normal and Disordered Voices

PURPOSE

Accurate estimation of daily patterns of vocal behavior is essential to understanding the role of voice use in voice disorders. Given that clinicians currently rely on patient self-report to assess daily vocal behaviors, this study sought to assess the accuracy with which adults with and without voice disorders can estimate their amount of daily voice use in terms of phonation time.

METHOD

Eighteen subjects (6 patients, 6 matched members of a control group without voice disorders, 6 low voice users) wore the accelerometer-based Ambulatory Phonation Monitor (APM; model 3200, KayPENTAX, Montvale, NJ) for at least 5 workdays. Subjects were instructed to provide hourly self-reports of time spent talking using a visual analog scale. Spearman correlation coefficients and errors between self-reported and APM-based estimates of phonation time revealed subject- and group-specific characteristics.

RESULTS

A majority of subjects exhibited a significant bias toward overestimating their phonation times, with an average absolute error of 113%. Correlation coefficients between self-reported and APM-based estimates of phonation time ranged from statistically nonsignificant to .91, reflecting large intersubject variability.

CONCLUSIONS

Subjects in all 3 groups were moderately accurate at estimating their hourly voice use, with a consistent bias toward overestimation. The results support the potential role that ambulatory monitoring could play in improving the clinical assessment of voice disorders.

Are children with stronger cognitive capacity more or less disturbed by classroom noise and dysphonic teachers?

PURPOSE

This study aimed to explore if dysphonic voice quality affects children's performance on a language comprehension test, the Test for Reception of Grammar-2 (TROG-2), performed in simultaneous background noise (non-semantic babble). A further aim was to investigate the role of Working Memory Capacity (WMC) and Executive Functioning (EF) in coping with the voice against a background of babble conditions.

METHOD

Ninety-three mainstreamed 8 year old children with typical language development were tested for WMC and EF. Two groups of children (n = 47/46) were formed and presented with recordings of TROG-2 instructions read by one female speaker: one group was presented with recordings with induced dysphonic voice quality, the other with recordings of typical voice. Both groups listened to the voice recordings in competing babble noise at a Signal-to-Noise Ratio of + 10 dB.

RESULT

Significant differences were found for the interaction between cognitive capacity and the TROG-2 results in relation to the voice conditions. In the dysphonic voice condition, children with better WMC results scored higher at the easier comprehension tasks. In the typical voice condition, children with better WMC and EF results scored higher on the more difficult tasks. Seventeen per cent of the variance for the TROG-2 results was explained by the WMC and EF results. There was no overall effect on the children's performance depending of voice condition.

CONCLUSION

The effect of the speaker's voice quality on children's performance varies depending on the prevalence of background babble noise and on the task demands. The dysphonic voice and babble noise seem to demand allocation of cognitive capacities at the cost of language comprehension.

Effects of pedagogical ideology on the perceived loudness and noise levels in preschools

High activity noise levels that result in detrimental effects on speech communication have been measured in preschools. To find out if different pedagogical ideologies affect the perceived loudness and levels of noise, a questionnaire study inquiring about the experience of loudness and voice symptoms was carried out in Iceland in eight private preschools, called "Hjalli model", and in six public preschools. Noise levels were also measured in the preschools. Background variables (stress level, age, length of working career, education, smoking, and number of children per teacher) were also analyzed in order to determine how much they contributed toward voice symptoms and the experience of noisiness. Results indicate that pedagogical ideology is a significant factor for predicting noise and its consequences. Teachers in the preschool with tighter pedagogical control of discipline (the "Hjalli model") experienced lower activity noise loudness than teachers in the preschool with a more relaxed control of behavior (public preschool). Lower noise levels were also measured in the "Hjalli model" preschool and fewer "Hjalli model" teachers reported voice symptoms. Public preschool teachers experienced more stress than "Hjalli model" teachers and the stress level was, indeed, the background variable that best explained the voice symptoms and the teacher's perception of a noisy environment. Discipline, structure, and organization in the type of activity predicted the activity noise level better than the number of children in the group. Results indicate that pedagogical ideology is a significant factor for predicting self-reported noise and its consequences.

Classroom Noise and Teachers' Voice Production

PURPOSE

The aim of this study was to research the associations between noise (ambient and activity noise) and objective metrics of teachers' voices in real working environments (i.e., classrooms).

METHOD

Thirty-two female and 8 male teachers from 14 elementary schools were randomly selected for the study. Ambient noise was measured during breaks in unoccupied classrooms and, likewise, the noise caused by pupils' activity during lessons. Voice samples were recorded before and after a working day. Voice variables measured were sound pressure level (voice SPL), fundamental frequency, jitter, shimmer, and the tilt of the sound spectrum slope (alpha ratio).

RESULTS

The ambient noise correlated most often with the fundamental frequency of men and voice SPL, whereas activity noise correlated with the alpha ratio and perturbation values. Teachers working in louder ambient noise spoke more loudly before work than those working in lower noise levels. Voice variables generally changed less during work among teachers working in loud activity noise than among those working in lower noise levels.

CONCLUSIONS

Ambient and activity noises affect teachers' voice use. Under loud ambient noise teachers seem to speak habitually loudly, and under loud activity noise teachers' ability to react to loading deteriorates.

Voice dosimetry and monitoring, with emphasis on professional voice diseases: Critical review and framework for future research

Professional voice has become an important issue in the field of occupational health. Similarly, voice diseases related to occupations gain interest in insurance medicine, particularly within the frame of specific insurance systems for occupational diseases. Technological developments have made possible dosimetry of voice loading in the work-place, as well as long-term monitoring of relevant voice parameters during professional activities. A critical review is given, with focus on the specificity of occupational voice use and on the point of view of insurance medicine. Remaining questions and suggestions for future research are proposed.

Voice Disorders in Occupations with Vocal Load in Slovenia

Aim

The aim of this paper is to compare the prevalence of voice disorders and the risk factors for them in different occupations with a vocal load in Slovenia.

Methods

A meta-analysis of six different Slovenian studies involving teachers, physicians, salespeople, catholic priests, nurses and speech-and-language therapists (SLTs) was performed. In all six studies, similar questions about the prevalence of voice disorders and the causes for them were included.

Results

The comparison of the six studies showed that more than 82% of the 2347 included subjects had voice problems at some time during their career. The teachers were the most affected by voice problems. The prevalent cause of voice problems was the vocal load in teachers and salespeople and respiratory-tract infections in all the other occupational groups. When the occupational groups were compared, it was stated that the teachers had more voice problems and showed less care for their voices than the priests. The physicians had more voice problems and showed better consideration of vocal hygiene rules than the SLTs. The majority of all the included subjects did not receive instructions about voice care during education.

Conclusions

In order to decrease the prevalence of voice disorders in vocal professionals, a screening program is recommended before the beginning of their studies. Regular courses on voice care and proper vocal technique should be obligatory for all professional voice users during their career. The inclusion of dysphonia in the list of occupational diseases should be considered in Slovenia as it is in some European countries.

Comparison of vocal loading parameters in kindergarten and elementary school teachers

PURPOSE Although a global picture exists of teachers' voice demands in general, few studies have compared specific groups of teachers to determine whether some are more at risk than others. This study compared the vocal loadings of kindergarten and elementary school teachers; professional and nonprofessional vocal load were determined for both groups. METHOD Twelve kindergarten and 20 elementary school female teachers without voice problems were monitored during 1 workweek using the Ambulatory Phonation Monitor. Vocal loading parameters analyzed were F0, SPL, time dose, distance dose, and cycle dose. RESULTS Comparisons between the groups showed significantly higher cycle dose and distance dose for kindergarten teachers than for elementary school teachers, in both professional and nonprofessional environments. Professional and nonprofessional voice use comparisons showed significant differences for all parameters, indicating that vocal load was higher in the professional environment for both groups. CONCLUSIONS The higher vocal doses measured in kindergarten teachers suggest that particular attention should be paid to this specific group of teachers. Although nonprofessional vocal load is lower than professional vocal load, it is important to take both into account because of their cumulative effects.

Associations between voice ergonomic risk factors and acoustic features of the voice

The associations between voice ergonomic risk factors in 40 classrooms and the acoustic parameters of 40 schoolteachers' voices were investigated. The risk factors assessed were connected to participants' working practices, working postures, and the indoor air quality in their workplaces. The teachers recorded spontaneous speech and sustained /a/ before and after a working day. Fundamental frequency, sound pressure level, the slope of the spectrum, perturbation, and harmonic-to-noise ratio were analysed. The results showed that the more the voice ergonomic risk factors were involved, the louder the teachers' voices became. Working practices correlated most often with the acoustic parameters; associations were found especially before a working day. The results suggest that a risky voice ergonomic environment affects voice production.

Variations in intensity, fundamental frequency, and voicing for teachers in occupational versus nonoccupational settings

PURPOSE

In this study, the authors created a more concise picture of the vocal demands placed on teachers by comparing occupational voice use with nonoccupational voice use.

METHOD

The authors used National Center for Voice and Speech voice dosimetry databank to calculate voicing percentage per hour as well as average dB SPL and fundamental frequency (F(0)). Occupational voice use (9:00 a.m.-3:00 p.m., weekdays) and nonoccupational voice use (4:00 p.m.-10:00 p.m., weekends) were compared (57 teachers, 2 weeks each).

RESULTS

Five key findings were uncovered: (1) Similar to previous studies, occupational voicing percentage per hour is more than twice that of nonoccupational voicing; (2) teachers experienced a wide range of occupational voicing percentages per hour (30+/-11% per hr); (3) average occupational voice was about 1 dB SPL louder than the nonoccupational voice and remained constant throughout the day; (4) occupational voice exhibited an increased pitch and trended upward throughout the day; and (5) some apparent gender differences were shown.

CONCLUSIONS

Data regarding voicing percentages, F(0), and dB SPL provide critical insight into teachers' vocal health. Further, because nonoccupational voice use is added to an already overloaded voice, it may add key insights into recovery patterns and should be the focus of future studies.

Comparison of voice-use profiles between elementary classroom and music teachers

Among teachers, music teachers are roughly four times more likely than classroom teachers to develop voice-related problems. Although it has been established that music teachers use their voices at high intensities and durations in the course of their workday, voice-use profiles concerning the amount and intensity of vocal use and vocal load have neither been quantified nor has vocal load for music teachers been compared with classroom teachers using these same voice-use parameters. In this study, total phonation time, fundamental frequency (F₀), and vocal intensity (dB SPL [sound pressure level]) were measured or estimated directly using a KayPENTAX Ambulatory Phonation Monitor (KayPENTAX, Lincoln Park, NJ). Vocal load was calculated as cycle and distance dose, as defined by Švec et al (2003), which integrates total phonation time, F₀, and vocal intensity. Twelve participants (n = 7 elementary music teachers and n = 5 elementary classroom teachers) were monitored during five full teaching days of one workweek to determine average vocal load for these two groups of teachers. Statistically significant differences in all measures were found between the two groups (P < 0.05) with large effect sizes for all parameters. These results suggest that typical vocal loads for music teachers are substantially higher than those experienced by classroom teachers (P < 0.01). This study suggests that reducing vocal load may have immediate clinical and educational benefits in vocal health in music teachers.

Speaker's comfort in teaching environments: voice problems in Swedish teaching staff

OBJECTIVES

The primary objective of this study was to examine how a group of Swedish teachers rate aspects of their working environment that can be presumed to have an impact on vocal behavior and voice problems. The secondary objective was to explore the prevalence of voice problems in Swedish teachers.

METHOD

Questionnaires were distributed to the teachers of 23 randomized schools. Teaching staff at all levels were included, except preschool teachers and teachers at specialized, vocational high schools. The response rate was 73%.

RESULTS

The results showed that 13% of the whole group reported voice problems occurring sometimes, often, or always. The teachers reporting voice problems were compared with those without problems. There were significant differences among the groups for several items. The teachers with voice problems rated items on room acoustics and work environment as more noticeable. This group also reported voice symptoms, such as hoarseness, throat clearing, and voice change, to a significantly higher degree, even though teachers in both groups reported some voice symptoms. Absence from work because of voice problems was also significantly more common in the group with voice problems--35% versus 9% in the group without problems.

CONCLUSION

We may conclude that teachers suffering from voice problems react stronger to loading factors in the teaching environment, report more frequent symptoms of voice discomfort, and are more often absent from work because of voice problems than their voice-healthy colleagues.

Measurement of vocal doses in speech: experimental procedure and signal processing

An experimental method for quantifying the amount of voicing over time is described in a tutorial manner. A new procedure for obtaining calibrated sound pressure levels (SPL) of speech from a head-mounted microphone is offered. An algorithm for voicing detection (kv) and fundamental frequency (F0) extraction from an electroglottographic signal is described. The extracted values of SPL, F0, and kv are used to derive five vocal doses: the time dose (total voicing time), the cycle dose (total number of vocal fold oscillatory cycles), the distance dose (total distance travelled by the vocal folds in an oscillatory path), the energy dissipation dose (total amount of heat energy dissipated in the vocal folds) and the radiated energy dose (total acoustic energy radiated from the mouth). The doses measure the vocal load and can be used for studying the effects of vocal fold tissue exposure to vibration.

Analysis of voice change during cellular phone use: a blinded controlled study

It is a growing belief that cellular phone use may be hazardous to the voice. This study aims to assess voice production in different conversational scenarios to identify any changes in vocal production that may be specific to cellular phone use. Twenty healthy participants were randomized to seven conversational scenarios: quiet conditions face to face; quiet conditions over a landline; quiet conditions using a cellular phone (QCP); quiet conditions using cellular phone with earpiece (QCPE); noisy conditions face to face (NFF); noisy conditions using cellular phone (NCP); and noisy conditions using cellular phone with earpiece (NCPE). In each condition, participants performed spontaneous speech, a standardized reading passage, and sustained voicing. Sound pressure levels (dB SPL) and fundamental frequencies (F(0)[Hz]) were measured. Subjects completed a 100-mm visual analog scale measuring vocal effort after each speaking scenario. Statistical analysis was performed using analysis of variance (ANOVA). There was a significant difference in dB SPL and F(0) between all quiet conditions relative to all noisy conditions (P<0.001). There was no difference in cellular phone use relative to any other conversational condition in mean dB SPL, respective of ambient noise. Vocal effort was rated greater for noisy conditions compared with quiet conditions. Cellular phone use does not lead to a significant change in voice production relative to other speaking conditions. Voice problems associated with cellular phone use may simply be a function of the increased amount of voice use and increased vocal loudness (Lombard effect) associated with speaking in noisy situations rather than a variable inherent to the phone.

Preliminary Study on the Quantitative Analysis of Vocal Loading Effects on Vocal Fold Dynamics Using Phonovibrograms

Objectives:

The purpose of the present study was to determine whether high-speed digital imaging with phonovibrogram (PVG) analysis would identify changes in vocal fold vibratory characteristics following prolonged reading (vocal fatigue) in subjects with normal voice to evaluate the voice effects of vocal loading.

Methods:

Three healthy subjects' larynges were examined with an endoscopic high-speed imaging system at 4 different levels of vocal load. Vocal fold dynamics were segmented and processed by PVGs. The PVG images were quantitatively described by a parameter set enabling an individual characterization of vocal fold dynamics. To reveal differences between the subjects, we performed a linear discrimination analysis. Within each subject, the identification of vocal loading effects was performed by statistical analysis (1-way analysis of variance), and 2-tailed paired t-tests were used as a consistency check between left and right vocal fold sides.

Results:

For each subject, the PVG analysis enabled a precise quantification of the entire range of vocal fold dynamics. Independently of the high-speed videos (vocal loads), each subject could be identified by his or her PVG parameters on linear discrimination analysis. In all subjects, the effect of vocal loading was reflected by alterations of PVG parameters representing the posterior opening and closing dynamics. Evaluation within subjects revealed slight asymmetric vibratory behavior between the left and right vocal folds, confirming earlier assumptions.

Conclusions:

Within the investigated subjects, vocal loading does affect the vibratory characteristics of the vocal folds. Left-right vocal fold vibratory asymmetries do occur in healthy voices and can be identified by PVGs. High-speed digital imaging in combination with PVG analysis seems to be a promising tool for investigation of vocal fold fatigue and disorders resulting even from small dynamic changes.

Acoustic Measures and Self-reports of Vocal Fatigue by Female Teachers

This study investigated the relation of symptoms of vocal fatigue to acoustic variables reflecting type of voice production and the effects of vocal loading. Seventy-nine female primary school teachers volunteered as subjects. Before and after a working day, (1) a 1-minute text reading sample was recorded at habitual loudness and loudly (as in large classroom), (2) a prolonged phonation on [a:] was recorded at habitual speaking pitch and loudness, and (3) a questionnaire about voice quality, ease, or difficulty of phonation and tiredness of throat was completed. The samples were analyzed for average fundamental frequency (F0), sound pressure level (SPL), and phonation type reflecting alpha ratio (SPL [1-5 kHz]-SPL [50 Hz-1 kHz]). The vowel samples were additionally analyzed for perturbation (jitter and shimmer). After a working day, F0, SPL, and alpha ratio were higher, jitter and shimmer values were lower, and more tiredness of throat was reported. The average levels of the acoustic parameters did not correlate with the symptoms. Increase in jitter and mean F0 in loud reading correlated with tiredness of throat. The results seem to suggest that, at least among experienced vocal professionals, voice production type had little relevance from the point of view of vocal fatigue reported. Differences in the acoustic parameters after a vocally loading working day mainly seem to reflect increased muscle activity as a consequence of vocal loading.

Vocal fatigue and its relation to vocal hyperfunction †

This article reviews current literature on vocal fatigue and considers its potential relationship to vocal hyperfunction. Vocal fatigue is defined by its symptoms. Specifically, the voice user perceives an increase in phonatory effort over time that may be accompanied by decreased phonatory function. Vocal fatigue can present as a pure condition, such that no specific aetiology is apparent, or as a component of other voice disorders. The underlying bases of vocal fatigue appear to include the neurophysiological and biomechanical effects of extended periods of phonation. It can also be a function of strategies used to adapt to extended periods of phonation, such as the use of excessive muscular tension and suboptimal vocal fold posturing. Studies that have attempted to identify observable responses that are reliably associated with vocal fatigue have met with limited success, but recent advances in research methodology are promising. This review addresses current approaches to the study of vocal fatigue, especially regarding subject selection, design variables, and measurement variables. Future studies should address the relationship between vocal fatigue and other voice disorders, differences in individual responses to vocal-loading tasks, and differential evaluation and management of the neuromuscular, biomechanical, and central processes involved in vocal fatigue.

Protocol Challenges for On-the-Job Voice Dosimetry of Teachers in the United States and Finland

The occupational voice use of teachers has been an important research topic over the last 10 years. However, data collection on vocal loading in teachers at and away from the workplace poses significant challenges to the research protocol. The challenges include recruitment of subjects, voice data collection on the job, and subject compliance and retention. The present article offers recommendations for coping with these protocol difficulties. The recommendations are based on the authors' experiences with long-term, on-the-job voice dosimetry of large subject groups of teachers in the United States and Finland.

Outcome of Resonant Voice Therapy for Female Teachers With Voice Disorders: Perceptual, Physiological, Acoustic, Aerodynamic, and Functional Measurements

Teachers have a high percentage of voice problems. For voice disordered teachers, resonant voice therapy is hypothesized to reduce voice problems. No research has been done on the physiological, acoustic, and aerodynamic effects of resonant voice therapy for school teachers. The purpose of this study is to investigate resonant voice therapy outcome from perceptual, physiological, acoustic, aerodynamic, and functional aspects for female teachers with voice disorders. A prospective study was designed for this research. The research subjects were 24 female teachers in Taipei. All subjects received resonant voice therapy in groups of 4 subjects, 90 minutes per session, and 1 session per week for 8 weeks. The outcome of resonant voice therapy was assessed from auditory perceptual judgment, videostroboscopic examination, acoustic measurements, aerodynamic measurements, and functional measurements before and after therapy. After therapy the severity of roughness, strain, monotone, resonance, hard attack, and glottal fry in auditory perceptual judgments, the severity of vocal fold pathology, mucosal wave, amplitude, and vocal fold closure in videostroboscopic examinations, phonation threshold pressure, and the score of physical scale in the Voice Handicap Index were significantly reduced. The speaking Fo, maximum range of speaking Fo, and maximum range of speaking intensity were significantly increased after therapy. No significant change was found in perturbation and breathiness measurements after therapy. Resonant voice therapy is effective for school teachers and is suggested as one of the therapy approaches in clinics for this population.