Toward Enhanced Voice-Related Self-Reports: Translation, Cross-Cultural Adaptation, and Validity

PURPOSE

This article provides a commentary on voice-related self-reports and presents various shortcomings endemic in the development and validation of these measures. Emphasis is placed on issues of construct validity, translation, and cross-cultural adaptation. Finally, a demonstration is provided to elucidate the importance of cross-cultural adaptation.

METHODS

An example of a voice-related self-report that lacks cross-cultural adaptation is provided, and a linguistic translation and cross-cultural adaptation process is outlined and demonstrated. A bilingual voice scientist, a bilingual speech-language pathologist (SLP), and two experts in voice-related self-reports completed a multistep linguistic translation and cross-cultural adaptation process and obtained back-translations from five SLPs native to the self-report's source culture.

RESULTS

Analyses of the back-translations demonstrated that the mean BiLingual Evaluation Understudy (BLEU) scores of the adapted items were higher overall than the back-translations of the original English items.

CONCLUSIONS

Unvalidated translations of voice-related self-reports are commonly used as a baseline to further translate the measure, and this deteriorates cross-cultural health equity. Cross-cultural adaptation is a crucial, but often overlooked process when translating and adapting self-reports. The present article calls for standardized methodologies with an emphasis on the necessity of careful translation methods and cultural adaptation processes.

The Effects of Reading Speed on Acoustic Voice Parameters and Self-reported Vocal Fatigue in Students

INTRODUCTION

Vocal loading tasks (VLTs) help researchers gather acoustic measurements and understand how a healthy speaker adjusts their voice in response to challenges. There is a dearth of evidence measuring the impact of speaking rate in VLTs on acoustic voice parameters and vocal fatigue.

OBJECTIVES

In the present study, the relationships between acoustic voice parameters and self-reported vocal fatigue were examined through an experimental VLT.

METHODS

38 students completed a 45-minute VLT which involved the recording of three randomized reading tasks. The tasks varied by the speed in which the words were presented (slow, medium, fast) on a computer monitor. Vocal fatigue ratings were measured subjectively using a Borg scale and negative adaptations to vocal loading were measured objectively using Sound Pressure Level (SPL, in dBA), fundamental frequency (fo, in semitones), and phonation time (Dt %).

RESULTS

Analysis indicated that vocal fatigue increases with time, and the slope of this relationship is affected by the speaking rate. SPL and fo increased with speaking rate and the standard deviation of SPL and fo decreased with speaking rate. On average, the male participants' phonation time values were 7.8% lower than the female participants. The rate of increase of vocal fatigue with time during the experiment was higher in the fast speaking style compared to the slow and medium ones.

CONCLUSION

The results provide support that the novel VLT altered multiple vocal parameters to induce measurable changes in vocal fatigue.

Reducing Vocal Fatigue With Bone Conduction Devices: Comparing Forbrain and Sidetone Amplification

PURPOSE

Altered auditory feedback research aims to identify methods to strengthen speakers' awareness of their own voicing behaviors, diminish their perception of vocal fatigue, and improve their voice production. This study aims to compare the effects of two bone conduction devices that provide altered auditory feedback.

METHOD

Twenty participants (19-33 years old, age: M [SD] = 25.5 [3.85] years) participated in a vocal loading task using a standard Forbrain device that provides filtered auditory feedback via bone conduction and a modified Forbrain device that provides only sidetone amplification, and a control condition with no device was also included. They rated their vocal fatigue on a visual analog scale every 2 min during the vocal loading task. Additionally, pre- and postloading voice samples were analyzed for acoustic voice parameters.

RESULTS

Across all participants, the use of bone conduction-altered auditory feedback devices resulted in a lower vocal fatigue when compared to the condition with no feedback. During the pre- and postvoice samples, the sound pressure level decreased significantly during feedback conditions. During feedback conditions, spectral mean and standard deviation significantly decreased, and spectral skew significantly increased.

CONCLUSION

The results promote bone conduction as a possible preventative tool that may reduce self-reported vocal fatigue and compensatory voice production for healthy individuals without voice disorders.

The Effect of Bilingualism on Production and Perception of Vocal Fry

AIMS

(1) Determine the difference in vocal fry phonation in English and Spanish productions among bilingual young adults, (2) Characterize the effect of spoken language and native language on vocal fry production among English-Spanish bilingual speakers, (3) Identify the effect of first and second language knowledge of the listener in the voice perceptual assessment, and (4) Define the effect of the environment of the assessment (in situ vs. online), in the voice perceptual assessment.

METHOD

Exploratory cross-sectional study of 34 bilingual (Spanish-English) speakers and six inexperienced listeners. Participating speakers produced two speech samples (one in English and one in Spanish). Six inexperienced monolingual and bilingual listeners performed the voice perceptual assessment of vocal fry, General grade of hoarseness, and Roughness using a 4-point rating scale.

RESULTS

Bilingual speakers used vocal fry more often when they were speaking in English (around 3%) compared with their production in Spanish (around 2%). Bilingual native English speakers used vocal fry more often during their productions in both languages compared with bilingual native Spanish speakers. Bilingual listeners had the highest agreement when identifying vocal fry in both languages.

CONCLUSIONS

Differences in production of vocal fry between native speakers of American English and native speakers of Spanish may be evidence of transferring of vocal behavior (such as vocal fry) from one language to the second one. In addition, being a bilingual listener may have an important effect on the perceptual identification of voice quality in English and Spanish, as well as vocal fry in English.

The effects of face masks on speech-in-speech recognition for children and adults

OBJECTIVES

This study explored the effects of different face masks on school-age children's and young adults' word recognition.

DESIGN

Speech recognition thresholds were measured adaptively in a two-talker speech masker using a closed-set picture pointing task. Target words were recorded by a female talker in five conditions: no mask, transparent mask, face shield, N95 mask and surgical mask.

STUDY SAMPLES

Thirty children (8-12 years) and 25 adults (18-25 years) with normal hearing.

RESULTS

Both children's and adults' word recognition was most negatively impacted by the face shield. Children's recognition was also impaired by the transparent mask. No negative effects were observed for the N95 or surgical mask for either age group.

CONCLUSION

School-age children, like young adults, are negatively affected by face masks when recognising speech in a two-talker speech masker, but the effects depend on the type of face mask being worn. Acoustic analyses suggest that the reflective materials used for masks impact speech signal quality and impair word recognition.

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.

Singing in different performance spaces: The effect of room acoustics on singers' perception

Classical singers' performances vary across different acoustic environments. The changes in the delivery are influenced by the singer's perception of the venue's acoustics. This study investigated these relationships using nine professional or semi-professional classical singers. Participants performed Giordani's "Caro mio ben" aria in five venues, and the acoustic parameters reverberance (T30 and EDT), clarity (C80), early vocal support (STv), and tonal color (EDTf) were measured. From a factor analysis of the subjective analysis three major factors emerged that, we propose, would represent three generalized percepts of Room Supportiveness, Room Noiselessness, and Room Timbre. These percepts correlated significantly with objective acoustic parameters traditionally linked to vocal support, reverberation, and timbre. Room Supportiveness and Room Noiselessness significantly contributed to the singers' likability of the acoustic environment, while Room Timbre did not. This indicates that singers' perceptual preference for a performance space may be influenced by factors affecting both auditory feedback and vocal function. These findings underscore the need for performing space designers to consider the unique needs of all stakeholders, including listeners and performers. The study contributes to the bridging of the gap between subjective perceptions and objective measurements, providing valuable insights for acoustic design considerations.

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.

Bilingualism and Voice Production. Differences Between Bilingual Latin-American Spanish- English Female Speakers and Monolingual Spanish Female Speakers During Spanish Productions

BACKGROUND

Speaking a second language influences jitter and shimmer when comparing monolingual English speakers with bilingual English-Spanish speakers. However, there is little information about differences on voice acoustic parameters when comparing monolingual Spanish speakers with bilingual Spanish-English speakers during their productions in Spanish.

AIM

Determine differences in five voice acoustic parameters commonly used in voice assessments (fundamental frequency, jitter, shimmer, Harmonics-to-Noise Ratio and Cepstral Peak Prominence Smoothed) which may be influenced by bilingualism.

METHODS

Exploratory cross-sectional study with two groups of female participants: monolingual Spanish speakers (n = 17), and bilingual Spanish-English speakers (n = 11). Participants filled out a questionnaire and recorded two voice samples (sustained vowel /a/ and reading). For this study, all the participants reported that their native language was Spanish.

RESULTS

Being a female bilingual speaker had a significant effect on Shimmer (%) with a Beta = -0.7. Similar tendency was found on harmonics-to-noise ratio (B = 0.2) and cepstral peak prominence smoothed (B = 0.2).

CONCLUSIONS

Our results indicate that being a native Spanish female speaker, speaking English as a second language, has significant small effects on voice acoustic parameters, such as shimmer, harmonics-to-noise ratio and cepstral peak prominence smoothed, during their productions in Spanish. This information is of interest for assessment and intervention plans of bilingual speakers at clinical and work-related settings.

Investigating the Impact of Visual Input on Voice Production in Virtual Reality

OBJECTIVE

This study explored the independent effects of visual input on voice production using virtual reality. Specifically, its effects on acoustic voice parameters and vocal status ratings, with the hypothesis that larger (a virtual lecture hall and theater compared to an office) and more full virtual rooms (75% of the capacity compared to 45%) would result in changes to the voice parameters and vocal status ratings.

METHODS

Voice production from 30 vocally healthy participants was recorded in six virtual reality conditions. After each condition, the participants provided vocal status ratings. The voice recordings were processed to calculate mean and standard deviation of sound pressure level and fundamental frequency, mean pitch strength, time dose, and cepstral peak prominence smoothed. The effects of the virtual reality conditions on these voice acoustic parameters and the vocal status ratings were analyzed.

RESULTS

The full virtual reality rooms resulted in significantly higher vocal fatigue and vocal discomfort ratings. The larger virtual reality rooms were significantly related to increases in mean and the standard deviation of sound pressure level, mean pitch strength, and cepstral peak prominence smoothed.

CONCLUSIONS

This study demonstrated that visual size and visual fullness input during speech tasks have distinct effects on voice production and self-reported vocal status. Visual size is related to voice acoustic outcomes, while visual fullness is related to self-reported outcomes.

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.

Assessing Acoustic Parameters in Early Music and Romantic Operatic Singing

OBJECTIVE

Since the recent early music (EM) revival, a subset of singers have begun to specialize in a style of singing that is perceptually different from the more "mainstream" romantic operatic (RO) singing style. The aim of this study is to characterize EM with respect to RO singing in terms of its vibrato characteristics and the singer's formant cluster.

STUDY DESIGN

This study presents a within-subject experimental design.

METHODS

Ten professional singers (5 F; 5M) versed in both EM and RO repertoire were enrolled in the study. Each singer recorded the first 10 bars of the famous Aria, "Amarilli Mia Bella" (Giulio Caccini, 1602) a cappella, in RO and EM styles, in random order. Three sustained notes were extracted from the acoustical recordings and were analyzed using the free user-friendly software Biovoice to extract five parameters: vibrato rate, vibrato extent, vibrato jitter (J_vib), vibrato shimmer, and quality ratio (QR), an estimation of the singer's formant power.

RESULTS

Vibrato in EM singing was characterized by a higher rate, a smaller extent, and less regular cycle-cycle period duration (higher J_vib) compared to RO singing. As in previous studies, RO singing presented a more prominent singer's formant, as indicated by a smaller QR.

CONCLUSIONS

Acoustical analysis of some vibrato characteristics and the Singer's Formant significantly differentiated EM from RO singing styles. Given the acoustical distinctions between EM and RO styles, future scientific and musicological studies should consider distinguishing between the two styles rather than using a singular term for and description of Western Classical singing.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Systematic Review of Literature on Speech Intelligibility and Classroom Acoustics in Elementary Schools

PURPOSE

Good verbal signals and low background noise are key factors for all children to maximize understanding of what is being taught. Classroom shape, surroundings, and even furnishings change how the environment "sounds" and how speech is "heard" in the classroom. Classroom acoustics is perhaps one of the most important, but often least considered, factors when designing a classroom. This systematic review aimed to characterize the relationship between intelligibility of speech and room acoustics in elementary schools based on the available evidence.

METHOD

Eligible studies were identified using two computerized databases: PubMed and Scopus. In total, 23 publications met our inclusion criteria: (a) Participants must have been from elementary schools, (b) acoustic characterization of the classroom must have been provided, (c) intelligibility tests must have been performed, and (d) articles were written in English.

RESULTS

After identifying the parameters and tests used to quantify the intelligibility of speech, the speech intelligibility scores were analyzed in relation with acoustical parameters found in the articles, particularly signal-to-noise ratio and speech transmission index. Our results highlighted the negative effect on intelligibility associated with poor transmission of the speech and poor classroom acoustics caused by long reverberation times and high background noise.

CONCLUSION

Good classroom acoustics is needed to improve speech intelligibility and, therefore, increase children's academic success.

Voice Biofeedback via Bone Conduction Headphones: Effects on Acoustic Voice Parameters and Self-Reported Vocal Effort in Individuals With Voice Disorders

PURPOSE

This study explores sidetone amplification (amplified playback of one's own voice) provided via bone conduction in participants with voice disorders. The effects of bone conduction feedback on acoustic voice parameters and vocal effort ratings are examined.

METHODS

Speech samples of 47 participants with voice disorders were recorded in three auditory feedback conditions: two with sidetone amplification delivered via bone conduction and one condition with no alteration of the feedback. After each task, the participants rated their vocal effort on a visual analog scale. The voice recordings were evaluated by a speech-language pathologist through the GRBAS scale and processed to calculate the within-participant centered sound pressure level (SPL) values, the mean pitch strength (PS), the time dose (Dt%), and cepstral peak prominence smoothed (CPPS). The effects of the feedback conditions on these acoustic parameters and vocal effort ratings were analyzed.

RESULTS

The high sidetone amplification condition resulted in a statistically significant decrease in the within-participant centered SPL values and mean pitch strength across all participants. The feedback conditions had no statistically significant effects on the vocal effort ratings, time dose (Dt%), or CPPS.

CONCLUSIONS

This study provides an evidence that bone conduction sidetone amplification contributes to a consistent adaptation in the within-participant centered SPL values (ΔSPL) in patients with vocal hyperfunction, glottal insufficiency, and organic/neurological laryngeal pathologies compared to conditions with no feedback.

Singing in different performance spaces: The effect of room acoustics on vibrato and pitch inaccuracy

Previous literature suggests that musical performers may be influenced to some extent by the acoustic environment in which they sing or play. This study investigates the influence of room acoustics on singers' voice production, by analyzing consecutive sung performances of classically trained students in five different performance spaces. The analyzed voice parameters were vibrato rate, extent, and pitch inaccuracy. Nine classically trained student-singers performed the same aria unaccompanied on a variable starting pitch that was consistent between spaces. Variance in vibrato rate and pitch inaccuracy was primarily explained by individual differences between singers. Conversely, the variance attributable to the rooms for the parameter of vibrato extent was larger compared to the variance attributable to the performers. Vibrato extent tended to increase with room clarity (C80) and was inversely associated with early decay time (EDT). Additionally, pitch inaccuracy showed a significant negative association with room support (ST_v). Singers seem to adjust their vocal production when performing in different acoustic environments. Likewise, the degree to which a singer can hear themself on stage may influence pitch accuracy.

Lombard effect, intelligibility, ambient noise, and willingness to spend time and money in a restaurant amongst older adults

Dining establishments are an essential part of the social experience. However, they are often characterized by high levels of background noise, which represents a barrier to effective communication. This particularly affects people suffering from hearing problems. Moreover, noise level exceeding normal conversational levels causes a phenomenon called the Lombard Effect, an involuntary tendency to increase the amount of vocal effort when talking in the presence of noise. Adults over 60 years represent the second largest population in the US and the majority of them suffer from some degree of hearing loss. The primary aim of the current study was to understand the effect of noise on vocal effort and speech intelligibility in a restaurant setting for adults over 60 years old with and without hearing loss. The secondary aim was to evaluate their perception of disturbance in communication and their willingness to spend time and money in a restaurant was affected by the varying levels of background noise. The results of this study showed background noise levels lower than 50 dB(A) will allow senior customers to minimize their vocal effort and to maximize their understanding of conversations, even for those with moderate to severe hearing loss. By setting a limit, it will also keep perceived disturbance low and willingness to spend time and money high among dining patrons.

Intelligibility of dysphonic speech in auralized classrooms

Voice disorders can reduce the speech intelligibility of affected speakers. This study evaluated the effect of noise, voice disorders, and room acoustics on vowel intelligibility, listening easiness, and the listener's reaction time. Three adult females with dysphonia and three adult females with normal voice quality recorded a series of nine vowels of American English in /h/-V-/d/ format (e.g., "had"). The recordings were convolved with two oral-binaural impulse responses acquired from measurements in two classrooms with 0.4 and 3.1 s of reverberation time, respectively. The stimuli were presented in a forced-choice format to 29 college students. The intelligibility and the listening easiness were significantly higher in quiet than in noisy conditions, when the speakers had normal voice quality compared to a dysphonic voice, and in low reverberated environments compared to high reverberated environments. The response time of the listener was significantly longer for speech presented in noisy conditions compared to quiet conditions and when the voice was dysphonic compared with healthy voice quality.

Do Voice Acoustic Parameters Differ Between Bilingual English-Spanish Speakers and Monolingual English Speakers During English Productions?

BACKGROUND

In addition to language differences in fundamental frequency between bilinguals and monolinguals, studies have also included other acoustic parameters to analyze differences in voice production associated with the language spoken.

AIM

To identify differences in voice acoustic parameters during English productions between monolingual and bilingual English speakers.

METHOD

Exploratory cross-sectional study with two groups of subjects: monolingual English speakers (n = 40), and bilingual English-Spanish speakers (n = 13). Participants filled out a questionnaire and recorded one reading in English (second sentence of Rainbow passage "The rainbow is a division of white light into many beautiful colors") under a "virtual-simulated" acoustic condition of No Noise and Medium Reverberation Time (0.8 seconds).

RESULT

Analysis by gender shows that monolingual speakers had higher fundamental frequency mode, and lower standard deviation of fundamental frequency compared to bilingual English-Spanish speakers. Bilingual male speakers had higher jitter and harmonics-to-noise ratio than monolingual speakers. On the contrary, female bilingual speakers had lower jitter and shimmer than monolingual speakers.

CONCLUSIONS

Speaking a second language may influence voice acoustic parameters, and therefore, should be considered when comparing acoustic speech metrics.

Hyoid Bone Syndrome and Dysphonia: Can Throat Pain Affect the Voice?

OBJECTIVES/HYPOTHESIS

To investigate the relationship of throat pain and dysphonia.

STUDY DESIGN

Prospective cohort study.

METHODS

Forty-five subjects presenting with hyoid bone syndrome (HBS) and dysphonia were asked to rate their pain on a numerical rating scale and complete the 10-item Voice-Related Quality of Life (V-RQOL) questionnaire prior to and at 1-week follow-up after treatment with triamcinolone injection into the attachments to the affected greater cornu(s). Wilcoxon signed-rank tests were applied to evaluate if the overall V-RQOL scores, the physical functioning (PF) and social-emotional (SE) domain scores, and pain scores changed significantly after treatment. To evaluate how change in perceived pain affected V-RQOL, the differences in the V-RQOL, PF, and SE domain scores, and in pain scores were calculated for each subject. Three linear models were fit to the response variables, ΔV-RQOL, ΔPF, and ΔSE, using ΔPain as a predicting variable.

RESULTS

V-RQOL, PF, and SE domain scores, and pain scores all improved significantly with treatment. A bigger decrease in the pain score led to a bigger increase in V-RQOL and domain scores, with slopes varying between -1.1 and -1.4. The PF domain scores showed the greatest improvement with decrease in pain scores.

CONCLUSIONS

Effective treatment of HBS led to improvement in patients' voice complaints, suggesting that throat pain may have a direct effect on voice. This may be related to compensatory perilaryngeal adjustments patients make when speaking with a "guarding" effect when they have throat pain.

LEVEL OF EVIDENCE

IV (Cohort study) Laryngoscope, 131:E2303-E2308, 2021.

Acoustic-Perceptual Correlates of Voice Among Steam Train Engineers: Effects of Noise and Hearing Protection

Occupational voice users are at a higher risk for developing voice disorders due to their vocal demands, such as prolonged periods of work-related voice use and nonideal environmental factors, such as speaking above background noise. The current study focused on the effects of background noise and hearing protection on acoustic-perceptual correlates of voice among steam train engineers. Fourteen participants phonated vowel /a/, read a phrase, and described a map under different noise and hearing protection conditions. Relative sound pressure level, relative fundamental frequency, and perceived vocal effort and disturbance decreased in the presence of hearing protection for all noise conditions. In contrast, these acoustic measures increased in the absence of hearing protection supporting Lombard effect. Overall, results of the current study provide insight into possible risks to vocal health in workers exposed to high levels of background noise and use hearing protection.

Effect of masks on speech intelligibility in auralized classrooms

This study explored the effects of wearing face masks on classroom communication. The effects of three different types of face masks (fabric, surgical, and N95 masks) on speech intelligibility (SI) presented to college students in auralized classrooms were evaluated. To simulate realistic classroom conditions, speech stimuli were presented in the presence of speech-shaped noise with a signal-to-noise ratio of +3 dB under two different reverberation times (0.4 s and 3.1 s). The use of fabric masks yielded a significantly greater reduction in SI compared to the other masks. Therefore, surgical masks or N95 masks are recommended in teaching environments.

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.

Reproducibility of Voice Parameters: The Effect of Room Acoustics and Microphones

INTRODUCTION

Computer analysis of voice recordings is an integral part of the evaluation and management of voice disorders. In many practices, voice samples are taken in rooms that are not sound attenuated and/or sound-proofed; further, the technology used is rarely consistent. This will likely affect the recordings, and therefore, their analyses.

OBJECTIVES

The objective of this study is to compare various acoustic outcome measures taken from samples recorded in a sound-proofed booth to those recorded in more common clinic environments. Further, the effects from six different commonly used microphones will be compared.

METHODS

Thirty-six speakers were recorded while reading a text and producing sustained vowels in a controlled acoustic environment. The collected samples were reproduced by a Head and Torso Simulator and recorded in three clinical rooms and in a sound booth using six different microphones. Newer measures (eg, Pitch Strength, cepstral peak prominence, Acoustic Voice Quality Index), as well as more traditional measures (eg Jitter, Shimmer, harmonics-to-noise ratio and Spectrum Tilt), were calculated from the samples collected with each microphone and within each room.

RESULTS

The measures which are more robust to room acoustic differences, background noise, and microphone quality include Jitter and smooth cepstral peak prominence, followed by Shimmer, Acoustic Voice Quality Index, harmonics-to-noise ratio, Pitch Strength, and Spectrum Tilt.

CONCLUSIONS

The effect of room acoustics and background noise on voice parameters appears to be stronger than the type of microphone used for the recording. Consequently, an appropriate acoustical clinical space may be more important than the quality of the microphone.

The Effect of Unilateral Hearing Protection on Vocal Intensity With Varying Degrees of Background Noise

INTRODUCTION

The Lombard effect (LE) is a phenomenon in which speakers adjust their vocal production by raising the volume in noisy environments. As a result, the LE can create problems of vocal strain, fatigue and potential injury.

OBJECTIVES

This study aims to examine the difference in vocal intensity output in subjects wearing unilateral hearing protection versus no hearing protection in the presence of background noise.

METHODS

Each subject was seated inside a sound booth wearing a head-mounted microphone. Subjects were asked to read an excerpt from "The Rainbow Passage" while various levels of background noise were played: 50, 60, 70, and 80 dBA (Multitalker Babble). Each noise level was played while the subject was with and without unilateral ear protection (Optime 98 Earmuff [3M]) in random order. The earmuff has a noise reduction rating of 25 dB. After each reading of the text, subjects were asked to rate communication disturbance, vocal clarity, and discomfort during talking using a 10 cm visual analogue scale.

RESULTS

The LE is reduced from 0.38 dB/dB to 0.29 dB/dB with unilateral ear occlusion. However, self-perception of disturbance, clarity and comfort were not affected by unilateral occlusion, only by noise level.

CONCLUSIONS

Unilateral hearing protection reduces the LE and may protect against phonotrauma when speaking in an environment with loud background noise.

Toward a Consensus Description of Vocal Effort, Vocal Load, Vocal Loading, and Vocal Fatigue

Purpose The purpose of this document is threefold: (a) review the uses of the terms "vocal fatigue," "vocal effort," "vocal load," and "vocal loading" (as found in the literature) in order to track the occurrence and the related evolution of research; (b) present a "linguistically modeled" definition of the same from the review of literature on the terms; and (c) propose conceptualized definitions of the concepts. Method A comprehensive literature search was conducted using PubMed/MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and Scientific Electronic Library Online. Four terms ("vocal fatigue," "vocal effort," "vocal load," and "vocal loading"), as well as possible variants, were included in the search, and their usages were compiled into conceptual definitions. Finally, a focus group of eight experts in the field (current authors) worked together to make conceptual connections and proposed consensus definitions. Results The occurrence and frequency of "vocal load," "vocal loading," "vocal effort," and "vocal fatigue" in the literature are presented, and summary definitions are developed. The results indicate that these terms appear to be often interchanged with blurred distinctions. Therefore, the focus group proposes the use of two new terms, "vocal demand" and "vocal demand response," in place of the terms "vocal load" and "vocal loading." We also propose standardized definitions for all four concepts. Conclusion Through a comprehensive literature search, the terms "vocal fatigue," "vocal effort," "vocal load," and "vocal loading" were explored, new terms were proposed, and standardized definitions were presented. Future work should refine these proposed definitions as research continues to address vocal health concerns.

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.

Work-related communicative profile of radio broadcasters: a case study

Purpose: To explore the short-term effect of work-related voice use on voice function, and noise exposure on hearing function among radio broadcasters. Method: A 1-week follow-up study with the participation of two radio broadcasters was conducted. Participants were monitored at the beginning and at the end of the working week. Premonitoring assessment on Monday (baseline measure) and postmonitoring assessment on Friday (follow-up measure) were performed to identify short-term effects of work-related conditions on voice and hearing function among radio broadcasters. Result: Changes in fundamental frequency postmonitoring at the end of the work week may be an indication of work-related vocal fatigue. Changes in the distribution and standard deviation of SPL during the monitoring from Monday to Friday may indicate control of the vocal loudness as a strategy to reduce vocal effort during broadcasting. During a 1-week follow-up, noise conditions during radio broadcasting were below occupational exposure limits and without noticeable consequences on hearing function. Conclusion: The work-related communicative profile of radio broadcasting, from this pilot study, suggests that although vocal demands in terms of vocal load may differ among broadcasters, the work-related conditions of broadcasting may play a role on vocal function among these occupational voice users. Concerning hearing function, our results indicate that occupational noise exposure represented minimal risk for hearing problems but the consequences of long-term noise exposure on hearing mechanisms may yet occur. Future studies with bigger sample sizes are warranted to confirm our results.

Lombard effect, ambient noise, and willingness to spend time and money in a restaurant

The objective of this study is to determine the minimum level of noise in a restaurant that starts the Lombard effect, and how it relates to the perceived communication disturbance and the willingness to spend time and money for a meal. Twenty-eight participants were instructed to read a passage in the presence of restaurant noise from 35 to 85 dB(A). As the noise level increased, participants began to be disturbed by the noise at 52 dB(A) and began to raise their voice at 57 dB(A). The willingness to spend time and money decreased starting at 52 dB(A).

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.

Vocal Fry and Vowel Height in Simulated Room Acoustics

PURPOSE

The purpose of this study was to investigate the influence of room acoustics in the relationship between vowel height and vocal fry.

METHODS

This was a cross-sectional study. Participants (college students, n = 40) read the first six sentences of "The Rainbow Passage" under nine simulated room acoustic conditions. Using two words with low vowels (act, pot) and two words with high vowels (shape, strikes) preceding a voiceless stop, the presence/absence of vocal fry was assessed using an automatic detection script. Generalized estimation equations were used to investigate the relationship between percentage of vocal fry, vowel height, and room acoustics.

RESULTS

The percentage of vocal fry was significantly higher for the low-height vowels compared with the high-height vowels (β = 1.21; standard er ror = 0.35), and for pink background noise present (β = 0.89; standard error = 0.35) compared with the condition without artificial noise added.

CONCLUSION

The results of this study indicate that young college students are more likely to produce fry phonation when producing low-height vowels under pink background noise condition compared with no noise conditions and high-height vowels. This result is of special interest for voice clinicians when designing therapy plans and vocal assessment protocols with fry-like components.

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.

Factors associated with vocal fry among college students

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Speech produced in noise: Relationship between listening difficulty and acoustic and durational parameters

Conversational speech produced in noise can be characterised by increases in intelligibility relative to such speech produced in quiet. Listening difficulty (LD) is a metric that can be used to evaluate speech transmission performance more sensitively than intelligibility scores in situations in which performance is likely to be high. The objectives of the present study were to evaluate the LD of speech produced in different noise and style conditions, to evaluate the spectral and durational speech modifications associated with these conditions, and to determine whether any of the spectral and durational parameters predicted LD. Nineteen subjects were instructed to speak at normal and loud volumes in the presence of background noise at 40.5 dB(A) and babble noise at 61 dB(A). The speech signals were amplitude-normalised, combined with pink noise to obtain a signal-to-noise ratio of -6 dB, and presented to twenty raters who judged their LD. Vowel duration, fundamental frequency and the proportion of the spectral energy in high vs low frequencies increased with the noise level within both styles. LD was lowest when the speech was produced in the presence of high level noise and at a loud volume, indicating improved intelligibility. Spectrum balance was observed to predict LD.

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.

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.

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.

Effect of Training and Level of External Auditory Feedback on the Singing Voice: Pitch Inaccuracy

BACKGROUND

One of the most important aspects of singing is the control of fundamental frequency.

OBJECTIVES

The effects on pitch inaccuracy, defined as the distance in cents in equally tempered tuning between the reference note and the sung note, of the following conditions were evaluated: (1) level of external feedback, (2) tempo (slow or fast), (3) articulation (legato or staccato), (4) tessitura (low, medium, or high), and (5) semi-phrase direction (ascending or descending).

METHODS

The subjects were 10 nonprofessional singers and 10 classically trained professional or semi-professional singers (10 men and 10 women). Subjects sang one octave and a fifth arpeggi with three different levels of external auditory feedback, two tempi, and two articulations (legato or staccato).

RESULTS

It was observed that inaccuracy was greatest in the descending semi-phrase arpeggi produced at a fast tempo and with a staccato articulation, especially for nonprofessional singers. The magnitude of inaccuracy was also relatively large in the high tessitura relative to the low and the medium tessitura for such singers. Contrary to predictions, when external auditory feedback was strongly attenuated by the hearing protectors, nonprofessional singers showed greater pitch accuracy than in the other external feedback conditions. This finding indicates the importance of internal auditory feedback in pitch control.

CONCLUSIONS

With an increase in training, the singer's pitch inaccuracy decreases.

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.

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

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

Effect of Training and Level of External Auditory Feedback on the Singing Voice: Volume and Quality

BACKGROUND

Previous research suggests that classically trained professional singers rely not only on external auditory feedback but also on proprioceptive feedback associated with internal voice sensitivities.

OBJECTIVES

The Lombard effect and the relationship between sound pressure level (SPL) and external auditory feedback were evaluated for professional and nonprofessional singers. Additionally, the relationship between voice quality, evaluated in terms of singing power ratio (SPR), and external auditory feedback, level of accompaniment, voice register, and singer gender was analyzed.

METHODS

The subjects were 10 amateur or beginner singers and 10 classically trained professional or semiprofessional singers (10 men and 10 women). Subjects sang an excerpt from the Star-Spangled Banner with three different levels of the accompaniment, 70, 80, and 90 dBA and with three different levels of external auditory feedback. SPL and SPR were analyzed.

RESULTS

The Lombard effect was stronger for nonprofessional singers than professional singers. Higher levels of external auditory feedback were associated with a reduction in SPL. As predicted, the mean SPR was higher for professional singers than nonprofessional singers. Better voice quality was detected in the presence of higher levels of external auditory feedback.

CONCLUSIONS

With an increase in training, the singer's reliance on external auditory feedback decreases.

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

Investigations into vocal doses and parameters were carried out on 40 primary school teachers (36 females and 4 males) in six schools in Italy, divided into two groups of three, A and B, on the basis of the type of building and the mid-frequency reverberation time in the classrooms, which was 1.13 and 0.79 s, respectively. A total of 73 working-day samples were collected (66 for females and 7 for males), from which 54 traditional lessons were analyzed separately. The average value over the working days of the mean sound pressure level of the voiced speech at 1 m from the teacher's mouth was 62.1 dB for the females and 57.7 dB for the males, while the voicing time percentage was 25.9 and 25.1 %, respectively. Even though the vocal doses and parameters did not differ for the two school groups, the differences in the subjective scores were significant, with enhanced scores in group B. A 0.72 dB increase in speech level per 1 dB increase in background noise level, L(A90), was found during traditional lessons, as well as an increase in the mean value of the fundamental frequency with an increase in L(A90), at a rate of 1.0 Hz/dB.

Subjective and objective speech intelligibility investigations in primary school classrooms

This work concerns speech intelligibility tests and measurements in three primary schools in Italy, one of which was conducted before and after an acoustical treatment. Speech intelligibility scores (IS) with different reverberation times (RT) and types of noise were obtained using diagnostic rhyme tests on 983 pupils from grades 2-5 (nominally 7-10 year olds), and these scores were then correlated with the Speech Transmission Index (STI). The grade 2 pupils understood fewer words in the lower STI range than the pupils in the higher grades, whereas an IS of ~97% was achieved by all the grades with a STI of 0.9. In the presence of traffic noise, which resulted the most interfering noise, a decrease in RT from 1.6 to 0.4 s determined an IS increase on equal A-weighted speech-to-noise level difference, S/N(A), which varied from 13% to 6%, over the S/N(A) range of -15 to +6 dB, respectively. In the case of babble noise, whose source was located in the middle of the classroom, the same decrease in reverberation time leads to a negligible variation in IS over a similar S/N(A) range.

[Effect of noise and reverberation on vocal effort and fatigue of primary school teachers]

Teachers are at a higher risk for occupation-related voice disorders than the general population. The aim of this work is the investigations on the relationships between vocal doses and clinical status, acoustical conditions (noise and reverberation) in the classrooms and subjective evaluations of vocal effort and fatigue. At clinical evaluation 41% of the teachers showed no sign of vocal disease. Students talking in the classroom is the most annoying, noise source in classrooms. The consequence of the poor acoustics in all the schools was the decrease in students question perception. The main cause of a vocal pathology was time dose.

Acanthamoeba T4 and T15 genotypes associated with keratitis infections in Italy

Thus far there is little data available concerning Acanthamoeba associated amoebic keratitis (AK) from Italy. In order to understand the incidence of Acanthamoeba in patients with ocular infections and to characterize the isolates at the molecular level, ocular specimens and contact lenses or lens case solutions from 140 patients were analysed by culture and by an 18S rRNA (Rns) gene-based PCR method. Nineteen (13.6%) patients showed Acanthamoeba culture positive samples. Eleven out of the 14 genetically characterized isolates were assigned to the T4 genotype. Three isolates, two of them from patients with keratitis responding to specific anti-Acanthamoeba therapy, were identified as belonging to the T15 genotype. This finding represents the first association between the T15 genotype and human amoebic keratitis. PCR amplification of the 18S ribosomal DNA proved to be a sensitive method, potentially able to detect Acanthamoeba without the need of long culture incubation, and thus considerably useful for clinical applications.