Speech Adjustments for Room Acoustics and Their Effects on Vocal Effort

Sex Differences in the Speech of Persons With and Without Parkinson's Disease

BACKGROUND

Sex differences are apparent in the prevalence and the clinical presentation of Parkinson's disease (PD), but their effects on speech have been less studied.

METHOD

Speech acoustics of persons with (34 females and 34 males) and without (age- and sex-matched) PD were examined, assessing the effects of PD diagnosis and sex on ratings of dysarthria severity and acoustic measures of phonation (fundamental frequency standard deviation, smoothed cepstral peak prominence), speech rate (net syllables per second, percent pause ratio), and articulation (articulatory-acoustic vowel space, release burst precision).

RESULTS

Most measures were affected by PD (dysarthria severity, fundamental frequency standard deviation) and sex (smoothed cepstral peak prominence, net syllables per second, percent pause ratio, articulatory-acoustic vowel space), but without interactions between them. Release burst precision was differentially affected by sex in PD. Relative to those without PD, persons with PD produced fewer plosives with a single burst: females more frequently produced multiple bursts, whereas males more frequently produced no burst at all.

CONCLUSIONS

Most metrics did not indicate that speech production is differentially affected by sex in PD. Sex was, however, associated with disparate effects on release burst precision in PD, which deserves further study.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24388666.

Effects of warm-up exercises on self-assessed vocal effort

PURPOSE

An elevated sense of vocal effort due to increased vocal demand is frequently reported by patients with voice disorders. However, effects of vocal warm-up on self-assessed vocal effort have not been thoroughly examined. A recently developed version of the Borg CR-10 Scale facilitates vocal effort assessments, following different vocal warm-up tasks.

METHODS

Effects of a short (5 min) vocal warm-up on self-assessed vocal effort was evaluated using the Borg CR-10. Twenty-six vocally healthy participants (13F, 13M, mean age 22.6), in two randomised groups, underwent sessions of either reading aloud or semi-occluded vocal tract exercises (SOVTE). Vocal effort was evaluated at four times: pre to post vocal warm-up and two silence periods. Non-parametric analyses for repeated measures and calculations for within-subject standard deviation were applied in group comparisons.

RESULTS

Following vocal warm-up, vocal effort ratings were increased to a statistically significant degree in both intervention groups compared to baseline ratings. After a 5-min rest in silence following completion of the vocal warm-up, vocal effort ratings returned to baseline levels in both groups. The drop in ratings immediately post warm-up compared to 5 min later was statistically significant for the SOVTE group.

CONCLUSIONS

Five minutes of vocal warm-up caused increased self-perceived vocal effort in vocally healthy individuals. The increased sense of effort dissipated faster following warm-up for the SOVTE group. When using the Borg CR-10 scale to track vocal effort, it may be beneficial to apply experience-based anchors.

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.

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.

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.

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.

Self-Perception of Vocal Effort in Response to Modeled Communication Demands

OBJECTIVES

The optimization of vocal effort given a response to a voice demand is a common clinical and vocal performance goal. Increases in vocal effort are often in response to communication limitations from both the interlocutors and the communication environment. This study investigates the relationship between vocal effort and vocal demands from changes and limitations imposed by the communication environment.

METHODS

Thirty-seven participants rated their vocal effort associated with a map description task in a range of communication demands. These demands included communication distance (from 1 m to 4 m), loudness goal (54 dB-66 dB), and excess background noise (53 dBA-71 dBA). The vocal effort ratings were compared across the different types and extents of vocal demand conditions.

RESULTS

As would be expected, there were significant increases in vocal effort levels from the control condition to the extremes of the distance and loudness goal vocal demands. Each increase in background noise resulted in distinct increases in vocal effort level. Participants were able to use the vocal effort scale to efficiently quantify expected increases in vocal demands.

CONCLUSIONS

Increases of vocal effort level accompany increases to vocal demands that exceed the habitual or expected communication. While voice training and vocal therapy are essential for reducing internal vocal demands, clients with a goal to reduce vocal effort should also consider external vocal demands such as communication distance and background noise.

The effects of vocal exertion on lung volume measurements and acoustics in speakers reporting high and low vocal fatigue

Purpose

Vocal exertion is common and often results in reduced respiratory and laryngeal efficiency. It is unknown, however, whether the respiratory kinematic and acoustic adjustments employed during vocal exertion differ between speakers reporting vocal fatigue and those who do not. This study compared respiratory kinematics and acoustic measures in individuals reporting low and high levels of vocal fatigue during a vocal exertion task.

Methods

Individuals reporting low (N = 20) and high (N = 10) vocal fatigue participated in a repeated measures design study over 2 days. On each day, participants completed a 10-minute vocal exertion task consisting of repeated, loud vowel productions at elevated F0 sustained for maximum phonation time. Respiratory kinematic and acoustic measures were analyzed on the 1^st vowel production (T0), and the vowels produced 2 minutes (T2), 5 minutes (T5), 7 minutes (T7), and 10 minutes (T10) into the vocal exertion task. Vowel durations were also measured at each time point.

Results

No differences in respiratory kinematics were observed between low and high vocal fatigue groups at T0. As the vocal exertion task progressed (T2-T10), individuals reporting high vocal fatigue initiated phonation at lower lung volumes while individuals with low vocal fatigue initiated phonation at higher lung volumes. As the exertion task progressed, total lung volume excursion decreased in both groups. Differences in acoustic measures were observed, as individuals reporting high vocal fatigue produced softer, shorter vowels from T0 through T10.

Conclusions

Individuals reporting high vocal fatigue employed less efficient respiratory strategies during periods of increased vocal demand when compared with individuals reporting low vocal fatigue. Individuals reporting high vocal fatigue had shorter maximum phonation time on loud vowels. Further study should examine the potential screening value of loud maximum phonation time, as well as the clinical implications of the observed respiratory patterns for managing vocal fatigue.

A Semiautomated Protocol Towards Quantifying Vocal Effort in Relation to Vocal Performance During a Vocal Loading Task

To increase the reliability and comparability of vocal loading studies, this paper proposes the use of a standardized approach with experiments that are [1] grounded on consistent definitions of terms related to vocal fatigue (vocal effort, vocal demand, and vocal demand response), and [2] designed to reduce uncertainty and increase repeatability. In the approach, a semi-automated vocal loading task that also increases efficiencies in collecting and preparing vocal samples for analysis was used to answer the following research question: To what extent is vocal effort and vocal demand response sensitive to changes in vocal demands (ie, noise only, noise plus duration)? Results indicate that the proposed protocol design consistently induced change in both vocal effort and vocal demand response, indicating vocal fatigue. The efficacy of future vocal loading studies would be improved by adopting a more consistent methodology for quantifying vocal fatigue, thus increasing interstudy comparability of results and conclusions.

Impact of Face Masks on Speech Acoustics and Vocal Effort in Healthcare Professionals

OBJECTIVES/HYPOTHESIS

We investigated speech acoustics and self-reported vocal symptoms in mask-wearing healthcare professionals. We hypothesized that there would be an attenuation of spectral energies and increase in vocal effort during masked speech compared to unmasked speech.

STUDY DESIGN

Within and between subject quasi-experimental design.

METHODS

We prospectively enrolled 21 healthcare providers (13 cisgender female, 8 cisgender male; M = 32.9 years; SD = 7.9 years) and assessed acoustics and perceptual measures with and without a face mask in place. Measurements included: 1) acoustic Vowel Articulation Index (VAI); 2) cepstral and spectral acoustic measures; 3) traditional vocal measures (e.g., fundamental frequency, intensity); 4) relative fundamental frequency (RFF); and 5) self-reported ratings of vocal effort and dyspnea.

RESULTS

During masked speech, there was a significant reduction in VAI, high-frequency information (>4 kHz), and RFF offset 10, as well as a significant increase in cepstral peak prominence and perceived vocal effort. Further analysis showed that high-frequency attenuation was more pronounced when wearing an N95 mask compared to a simple mask.

CONCLUSIONS

Face masks pose an additional barrier to effective communication that primarily impacts spectral characteristics, vowel space measures, and vocal effort. Future work should evaluate how long-term mask use impacts vocal health and may contribute to vocal problems.

LEVEL OF EVIDENCE

3 Laryngoscope, 132:391-397, 2022.

Voice amplifier: effects on dose and vocal intensity of teachers without dysphonia

PURPOSE

Analyze the interference of using the voice amplifier in vocal dose of non-dysphonic teachers.

METHODS

This is an experimental study comparing people from the same ambience compound for 20 teachers from municipal elementary school in Belo Horizonte/MG. After consent, the participants were requested to answer the vocal symptom scale questionnaire (ESV) and later participated in two different moments of the study, for which they randomly selected. In the first moment, the participants used only the vocal dosimeter and in the second, they used the vocal dosimeter and the voice amplifier. The measurements were recorded by the device for 1h40m, in the classroom that the teachers taught. The time between the two measurements was one week, with the same room, the same time and the same discipline being taught, at both times.

RESULTS

The intensity parameter was the only one that showed difference with the use of the voice amplifier.

CONCLUSION

Use voice amplification while non-dysphonic teachers are teaching doesn't affect the fundamental frequency and vocal dose measure in the acoustics parameters. The vocal intensity is smaller when teacher uses the vocal amplification.

Relationship Between Tasked Vocal Effort Levels and Measures of Vocal Intensity

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

High-resolution spherical directivity of live speech from a multiple-capture transfer function method

Although human speech radiation has been a subject of considerable interest for decades, researchers have not previously measured its directivity over a complete sphere with high spatial and spectral resolution using live phonetically balanced passages. The research reported in this paper addresses this deficiency by employing a multiple-capture transfer function technique and spherical harmonic expansions. The work involved eight subjects and 2522 unique sampling positions over a 1.22 or 1.83 m sphere with 5° polar and azimuthal-angle increments. The paper explains the methods and directs readers to archived results for further exploration, modeling, and speech simulation in acoustical environments. Comparisons of the results to those of a KEMAR head-and-torso simulator, lower-resolution single-capture measurements, other authors' work, and basic symmetry expectations all substantiate their validity. The completeness and high resolution of the measurements offer insights into spherical speech directivity patterns that will aid researchers in the speech sciences, architectural acoustics, audio, and communications.

Voice and Respiratory Characteristics of Men and Women Seeking Treatment for Presbyphonia

BACKGROUND AND OBJECTIVES

Impaired respiratory function could potentially explain why some older speakers experience voice-related handicap whereas others do not, despite presenting with similar age-related laryngeal characteristics. The objectives of this study were therefore to (1) describe voice and respiratory function across men and women in a sample of treatment-seeking patients with presbyphonia; (2) assess how respiratory function differed from the general elderly population, based on normative data; and 3) discuss how respiratory function may play a role in the development of voice symptoms across men and women.

METHODS

Twenty one participants with presbyphonia underwent respiratory assessments (spirometry and respiratory muscle strength testing) in addition to standard of care voice assessments. Respiratory variables included forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), FEV₁/FVC, maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP).

RESULTS

Voice features were consistent with the diagnosis of presbyphonia and values did not different significantly between males and females, although some trends were noted. Regarding respiratory variables, one-third of the participants (n = 7) presented with FVC and FEV₁ less than 80% of predicted, and 57% (n = 12) were <90% of predicted. Nine percent of the males (n = 1) and none of the females had a MIP below the lower limit of normal (LLN) expected for their age, sex, and weight. Eighteen percent of the males (n = 2) and 20% of the females (n = 2) fell below the LLN for MEP.

CONCLUSION

Our sample of participants with presbyphonia included a non-negligible proportion of patients with decreased percent predicted values of FVC and FEV₁, and with respiratory muscle strength (MEP) below the LLN. Standardized values of pulmonary function were not different across sexes, indicative of a similar respiratory health. However, a lower raw pulmonary function and respiratory muscle strength in women may compound laryngeal changes and have an impact on perceived voice-related handicap. Together, findings warrant further studies to explore the impact of decreased respiratory function on voice and, ultimately, on the response to voice therapy in patients with presbyphonia.

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.

Acoustic correlates of vocal effort: External factors and personality traits

OBJECTIVES

To develop an experimental protocol to study the vocal effort generated by introducing barriers to communication, and its relationship with certain personality traits.

MATERIAL AND METHODS

The experimental protocol consisted of an interactive game in which the subject gave an investigator instructions to adopt various body positions (semi-directed communication situation). The Control situation included no constraints on communication. Then a Distance Constraint (increased distance between subject and investigator) and a Time Constraint (generation of performance stress by putting the subject in competition with others) were introduced. The vocal parameters studied comprised vocal intensity and fundamental frequency in the middle of the vowel of 3 target phonemes. Subjects also took the NEO FFI-R personality test.

RESULTS

The study included 41 women aged between 18 and 52 years. Vocal intensity and fundamental frequency increased significantly with the introduction of the constraints (P<0.05), intensity passing from 75.5dB to 81.8dB and frequency from 249.4Hz to 335.8Hz. No correlations were found between these changes and results for the various personality traits.

CONCLUSIONS

This ecological protocol enables the impact of both physical and emotional obstacles to communication to be studied. No correlations between vocal effort and personality traits emerged. A larger-scale study would be necessary to analyze the continuum between vocal effort and vocal forcing, to improve speech therapy for dysfunctional dysphonia.

Effects of added absorption on the vocal exertions of talkers in a reverberant room

Occupational speech users such as schoolteachers develop voice disorders at higher rates than the general population. Previous research has suggested that room acoustics may influence these trends. The research reported in this paper utilized varying acoustical conditions in a reverberant room to assess the effects on vocal parameters of healthy talkers. Thirty-two participants were recorded while completing a battery of speech tasks under eight room conditions. Vocal parameters were derived from the recordings and the statistically significant effects of room acoustics were verified using mixed-model analysis of variance tests. Changes in reverberation time (T₂₀), early decay time (EDT), clarity index (C₅₀), speech transmission index (STI), and room gain (G_RG) all showed highly correlated effects on certain vocal parameters, including speaking level standard deviation, speaking rate, and the acoustic vocal quality index. As T₂₀, EDT, and G_RG increased, and as C₅₀ and STI decreased, vocal parameters showed tendencies toward dysphonic phonation. Empirically derived equations are proposed that describe the relationships between select room-acoustic parameters and vocal parameters. This study provides an increased understanding of the impact of room acoustics on voice production, which could assist acousticians in improving room designs to help mitigate unhealthy vocal exertion and, by extension, voice problems.

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.

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.

Modeling Speech Level as a Function of Background Noise Level and Talker-to-Listener Distance for Talkers Wearing Hearing Protection Devices

PURPOSE

Studying the variations in speech levels with changing background noise level and talker-to-listener distance for talkers wearing hearing protection devices (HPDs) can aid in understanding communication in background noise.

METHOD

Speech was recorded using an intra-aural HPD from 12 different talkers at 5 different distances in 3 different noise conditions and 2 quiet conditions.

RESULTS

This article proposes models that can predict the difference in speech level as a function of background noise level and talker-to-listener distance for occluded talkers. The proposed model complements the existing model presented by Pelegrín-García, Smits, Brunskog, and Jeong (2011) and expands on it by taking into account the effects of occlusion and background noise level on changes in speech sound level.

CONCLUSIONS

Three models of the relationship between vocal effort, background noise level, and talker-to-listener distance for talkers wearing HPDs are presented. The model with the best prediction intervals is a talker-dependent model that requires the users' unoccluded speech level at 10 m as a reference. A model describing the relationship between speech level, talker-to-listener distance, and background noise level for occluded talkers could eventually be incorporated with radio protocols to transmit verbal communication only to an intended set of listeners within a given spatial range-this range being dependent on the changes in speech level and background noise level.

Gender Differences in the Reporting of Vocal Fatigue in Teachers as Quantified by the Vocal Fatigue Index

OBJECTIVES

Occupational voice users report higher instances of vocal health problems. Women, who are more likely than men to report voice problems, are the largest members of some occupational voice users, such as teachers. While a common complaint among this population is vocal fatigue, it has been difficult to quantify. Therefore, the goal of this study is to quantify vocal fatigue generally in school teachers and investigate any related gender differences.

METHODS

Six hundred forty (518 female, 122 male) teachers were surveyed using an online questionnaire consisting in part of the Vocal Fatigue Index (VFI), an index specifically designed to quantify vocal fatigue.

RESULTS

Compared to vocally healthy adults, the teachers surveyed were 3 times as likely to report vocal tiredness or vocal avoidance and over 3 times as likely to report physical voice discomfort. Additionally, female teachers were more likely to have scores approaching those with dysphonia.

CONCLUSIONS

The VFI quantified elevated levels of vocal fatigue in teachers, with a significant prevalence of symptoms reported among females compared to males. Further, because the VFI indicated elevated complaints (between normal and dysphonic) in a population likely to be elevated, the VFI might be used to identify early indications of voice problems and/or track recovery.

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.