Vocal Impact of a Prolonged Reading Task at Two Intensity Levels: Objective Measurements and Subjective Self-Ratings

Detecting of Voice Fatigue With Artificial Intelligence

Voice fatigue (VF) has many symptoms and can occur after extended or brief voice use, depending on the presence or absence of voice pathology, and other factors. However, fatigue is difficult to detect and quantify through current approaches. This study explores the use of artificial intelligence (AI) in the automatic detection and analysis of VF, presenting a novel approach to detect and monitor the condition.

OBJECTIVE

This study aims to create an AI-based system for detecting VF. The AI model's performance is evaluated against traditional methods of assessment conducted by speech-language pathologists (SLPs).

METHODS

Voice samples were collected from individuals experiencing varying levels of VF. To validate these samples, we calculated fo, increases that have been shown to be correlated with VF, at the beginning and end of the recordings. The samples were processed using a machine learning model trained to recognize patterns associated with VF. To build the model, we extracted embeddings from an ECAPA-TDNN model that has been shown to capture changes in the voice characteristics of a speaker over time and used a Convolutional Neural Network for classification. To validate the model, the model's accuracy in detecting VF was compared with assessments from SLPs.

RESULTS

We achieved an accuracy score of 93% on our dataset of English academic lectures and podcasts. As further validation, we asked three experienced SLPs to classify audio segments from our dataset and compared their responses to the classifications from our model, and achieved an accuracy of 86% as compared to their ratings.

CONCLUSION

The application of AI in the detection of VF shows a generalizable approach for the analysis of VF. Future research will incorporate patient data to validate further the models that we created.

Effects of Back Pressure on the Feasibility and Tolerability of Laryngeal Diadochokinetic Exercise: A Pilot Study

BACKGROUND

The term vocal demand response refers to how speakers meet vocal demands. Vocal loading tasks with predetermined demand parameters (duration, pitch, loudness, etc) have been used in research to study the vocal demand response; these have historically consisted of loud sustained vowel and loud speech tasks. Tasks founded on laryngeal diadochokinesis (LDDK) may be viable alternatives, especially if demand parameters such as exercise-rest ratio and fluid back pressure are concurrently modulated.

OBJECTIVES

To explore the effects of four fluid back pressure conditions (0, 5, 10, and 15 cm H2O) on several measures of subjective participant experience, feasibility, and tolerability during intervallic laryngeal diadochokinetic exercise.

METHODS

Participants (n = 12) completed 15-minute trials of LDDK in 30-second rest and exercise intervals against four counterbalanced back pressure conditions: 0, 5, 10, and 15 cm H2O. The effects of back pressure on (1) ratings of perceived vocal exertion, (2) prevalence of adverse effects such as shortness of breath or lightheadedness, (3) subjective difficulty of sustaining LDDK, (4) number of exercise intervals completed, (5) rankings of participant-preferred back pressure levels, and (6) expert ratings of auditory-perceptual diadochokinetic strength were assessed descriptively.

RESULTS

Perceived vocal exertion, lightheadedness, and subjective laryngeal diadochokinetic difficulty increased as back pressure increased. Number of intervals completed, auditory-perceptual diadochokinetic strength, and participant rankings of back pressure conditions, by contrast, decreased as back pressure increased. 0 and 5 cm H2O were the most preferred back pressure conditions overall.

DISCUSSION

Fluid back pressure was feasible and broadly tolerated during 15-minute trials of vocal exercise. However, the transition from 5 → 10 cm H2O appeared to represent an inflection point in our results: a minority of participants did not tolerate exercise at 10 cm H2O, becoming a majority at 15 cm H2O. We conclude that fluid back pressure should be restricted to values between 0 and 10 cm H2O during LDDK.

The Impact of a Vocal Loading Task on Voice Characteristics of Female Speakers With Benign Vocal Fold Lesions

OBJECTIVES

To examine the effect of a vocal loading task on measures of vocal structure and function in females with benign vocal fold lesions (BVFLs) and determine if change is observed in voice and lesion characteristics.

STUDY DESIGN

Prospective cohort study.

METHODS

Twenty-eight (n = 28) female subjects with phonotraumatic BVFLs completed a vocal loading task of 30 minutes of reading aloud at 75-85 dBA. Multidimensional voice evaluation was completed pre- and post-load, including audio and videostroboscopy recordings and images for expert perceptual ratings and acoustic and aerodynamic evaluation. Subjects also scored themselves using a 10 cm visual analogue scale for Perceived Phonatory Effort, and completed the Evaluation of Ability to Voice Easily, a 12 item self-report scale of current perceived speaking voice function. An exploratory rather than confirmatory approach to data analysis was adopted. The direction and magnitude of the change scores (pre- to post-load) for each individual, across a wide variety of instrumental and self-report measures, were assessed against a Minimal Clinically Important Difference criteria.

RESULTS

Observations of change and the direction of change in vocal response of individuals with BVFLs to 30 minutes of loud vocal load was variable. Minimal to no change was noted for participants pre- to post-load as rated perceptually, for auditory and videostroboscopy samples. For most instrumental measures, change was shown for many participants including an overall improvement in aerodynamic and acoustic measures of function and efficiency post-load for 20 participants (77%) and decline in function for 4 participants (15%). Self-reported effort and vocal function post-load was multidirectional with similar numbers of participants reporting no change, improved function or a decline.

CONCLUSION

Subjects with BVFLs demonstrate change in vocal function following 30 minutes of vocal load. While this change can be variable and multidirectional, overall improvement was observed in instrumental measures of function and efficiency for most participants. Some participants perceived this change to be an increase in effort, some a reduction in effort and some perceived no change. Improved vocal function despite relative lesion stability can seemingly occur after loading in some pathological voices.

Phonatory Tasks and Outcome Measures for Assessing Vocal Fatigue: A Scoping Review

OBJECTIVES

To map the phonatory tasks and the result measures used to evaluate vocal fatigue in vocally healthy individuals.

METHODS

This is a scoping review based on the following research question: What are the phonatory tasks and outcome measures used for the evaluation of vocal fatigue in vocally healthy individuals? The construction of the search strategy followed the PCC strategy; population: vocally healthy adult individuals; concept: phonatory tasks and vocal evaluation measures; and context: vocal fatigue. The search was performed electronically in the databases Medline (PubMed), LILACS (BVS), SCOPUS (Elsevier), Web of Science (Clarivate), EMBASE, and COCHRANE. A manual search in the references of the selected articles and in the journal with the highest number of publications was also performed. The selection of articles was based on reading the titles, abstracts, and full text, applying the eligibility criteria. The selected articles were related to the evaluation of vocal fatigue in healthy individuals from a predetermined vocal load task. Data regarding the characteristics of the publication, sample, phonatory tasks, and outcomes were extracted. The results were presented in a descriptive format, due to a frequency distribution analysis.

RESULTS

In total, 3756 studies were identified during the search, of which 60 were selected. The most used vocal load activity was the reading task, with duration ranging from 46 to 120 minutes. The (1) sustained vowel /a/ and (2) the reading of texts and phrases, both in usual intensity and frequency without the interference of the researcher, were the most used evaluation tasks. The most used outcome measures are the following: (1) acoustic parameters-fundamental frequency [fo] (mean, variance), sound pressure level (mean), local jitter (%), local shimmer (%), cepstral peak prominence (mean); (2) vocal self-assessment by the validated instruments-Perceived Phonatory Effort Scale, Visual Analog Scale, Borg-CR-10 Scale.

CONCLUSIONS

There is a diversity of phonatory tasks and outcome measures recurrently used in scientific articles to evaluate the signs of vocal fatigue in vocally healthy individuals. The most used vocal sample to evaluate vocal fatigue was the sustained vowel /a/ in habitual intensity and frequency without the interference of the researcher. The most frequently reported outcome measures for the assessment of immediate vocal fatigue effects were the acoustic analysis and vocal self-assessment.

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.

Voice Acoustics and Vocal Effort in Mask-Wearing Healthcare Professionals: A Comparison Pre- and Post-Workday

OBJECTIVE

We evaluated voice acoustics and self-perceptual ratings in healthcare workers required to wear face masks throughout their workday.

METHODS

Eighteen subjects (11 cisgender female, 7 cisgender male; M = 33.72 years, SD = 8.30) completed self-perceptual ratings and acoustic recordings before and after a typical workday. Chosen measures were specific to vocal effort, dysphonia, and laryngeal tension. Mixed effects models were calculated to determine the impact of session, mask type, sex, and their interactions on the set of perceptual and acoustic measures.

RESULTS

The subjects self-reported a significant increase in vocal effort following the workday. These perceptual changes coincided with an increase in vocal intensity and harmonics-to-noise ratio, but decrease in relative fundamental frequency offset 10. As expected, men and women differed in measures related to fundamental frequency and vocal tract length.

CONCLUSION

Healthcare professionals wearing masks reported greater vocal symptoms post-workday compared to pre-workday. These symptoms coincided with acoustic changes previously related to vocal effort; however, the degree of change was considered mild. Further research is needed to determine whether vocal hygiene strategies may reduce vocal symptoms in mask-wearing workers.

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.

A Vocal Hygiene Program for Mitigating the Effects of Occupational Vocal Demand in Primary School Teachers

PURPOSE

Teachers are occupational voice users with significant vocal demand. This study examined if a vocal hygiene program could mitigate the effects of occupational vocal demand in primary school teachers across 1 month.

METHOD

Sixty female teachers participated, with 30 in an experimental group receiving vocal hygiene education plus daily home practice for 1 month and 30 in a control group with no intervention. Their vocal changes across the month were quantified with (a) acoustic measures on fundamental frequency (f_o), vocal intensity, jitter and shimmer, harmonics-to-noise ratio, and smoothed cepstral peak prominence and (b) Voice Handicap Index (VHI-10) and Vocal Fatigue Index (VFI) scores.

RESULTS

Analysis of covariance showed significantly larger changes (significant decreases) in conversational f_o and in jitter for the experimental group relative to the control group. Post hoc pairwise comparisons following repeated-measures analysis of variance showed significant decreases in conversational f_o and in jitter across the month for the experimental group. No significant differences in VHI-10 and VFI scores were found between the groups.

CONCLUSIONS

Vocal demand-related changes in acoustic measures could be partially mitigated with the vocal hygiene program. Future studies with a more refined intervention program and more long-term follow-up are recommended to better understand the long-term benefits of vocal hygiene programs on primary school teachers.

Outcomes of Vocal Hygiene Program in Facilitating Vocal Health in Female School Teachers With Voice Problems

BACKGROUND

Teachers suffer greater impacts of voice problems due inappropriate voice use and other contributing factors such as physiological, environmental, and individual & work related issues. Structured vocal hygiene programs (VHP) prevent/reduce the risk of vocal trauma and promote vocal health in teachers. This study aimed to estimate the outcome of instituting a sociocultural relevant vocal hygiene program in facilitating vocal health among female school teachers using a comprehensive voice assessment protocol.

METHOD

VHP was developed emphasizing adequate hydration, healthy vocal diet, posture and alignment, vocal practices while teaching, and ideal speaking environment. This was administered via a face to face session to seventeen female teachers with voice concerns. All underwent a comprehensive voice assessment (subjective, objective, and self-perceptual vocal measures) before and four weeks after the VHP. Inter-rater reliability for perceptual and visual examination was estimated using Intra-Class Coefficient. Wilcoxon signed ranks test was used to compare the pre- and post-treatment measures of continuous variables (acoustic, Maximum phonation time, s/z ratio, Vocal Fatigue Index [VFI] & Voice Disorder Outcome Profile [V-DOP]), and McNemar test was used for categorical variables (vocal health questionnaire, visual examination of larynx and perceptual evaluation of voice).

RESULTS

Teachers reported reduction of unhealthy vocal & nonvocal practices after VHP. Improvements in vocal and related symptoms such as sensation of heart burn (P = 0.031), discomfort around the throat (P = 0.008), inadequate breath control while speaking (P = 0.016) were noticed. Perceptually, minimal improvement was seen in voice quality (overall grade). However, MPT & s/z ratio showed no significant difference. Improvement was observed in frequency range (P = 0.004), low I₀ (P = 0.044), shimmer (P = 0.017), and DSI (P = 0.013). Changes were evident in all parameters of stroboscopic evaluation (except nonvibratory portion & ventricular fold hyper-adduction). V-DOP scores indicated positive change in the overall severity (P = 0.002), physical (P = 0.003) and functional domain (P = 0.034). VFI indicated improvement in teachers voice after a period of voice rest (P = 0.048).

CONCLUSION

Though VHP facilitated in improving the teachers' awareness of at risk phono-traumatic behaviors and vocal health, its efficiency was limited in producing physiological improvement in teachers' voice. The comparison of vocal metrics before & after the treatment provides information on changes that can be expected in teachers after guiding them through a systematic VHP.

Detecting Vocal Fatigue with Neural Embeddings

Vocal fatigue refers to the feeling of tiredness and weakness of voice due to extended utilization. This paper investigates the effectiveness of neural embeddings for the detection of vocal fatigue. We compare x-vectors, ECAPA-TDNN, and wav2vec 2.0 embeddings on a corpus of academic spoken English. Low-dimensional mappings of the data reveal that neural embeddings capture information about the change in vocal characteristics of a speaker during prolonged voice usage. We show that vocal fatigue can be reliably predicted using all three types of neural embeddings after 40 minutes of continuous speaking when temporal smoothing and normalization are applied to the extracted embeddings. We employ support vector machines for classification and achieve accuracy scores of 81% using x-vectors, 85% using ECAPA-TDNN embeddings, and 82% using wav2vec 2.0 embeddings as input features. We obtain an accuracy score of 76%, when the trained system is applied to a different speaker and recording environment without any adaptation.

Potential Biophysiological Mechanisms Underlying Vocal Demands and Vocal Fatigue

Patients with complaint of vocal fatigue have perceptual, acoustic, and aerodynamic outcomes that are heterogeneous in nature. One reason may be due to different underlying biophysiological mechanisms that lead to these heterogeneous clinical presentations. Five potential mechanisms are proposed: neuromuscular, metabolic, vocal tissue, afferent, and central neural. Analytical frameworks and study designs to study these mechanisms are also addressed. A better understanding of biophysiological mechanisms of vocal fatigue can improve precision of therapeutic approaches. It can also help shift management from symptom-based to etiology-focused approaches for vocal fatigue.

The Reliability and Validity of the Mandarin Chinese Version of the Vocal Fatigue Index: Preliminary Validation

PURPOSE

This study attempted to develop and to preliminarily validate the Mandarin Chinese version of the Vocal Fatigue Index (VFI) as a standardized self-assessment questionnaire tool for potential clinical applications.

METHOD

The experimental procedure involved (a) cross-cultural adaptation of the VFI into the Mandarin Chinese version (CVFI), (b) evaluation by an expert panel, (c) back translation, (d) pilot testing, and (e) validation of the questionnaire by three participant groups: 50 with voice disorders, 50 occupational voice users (at-risk group), and 50 with normal voice (control group). Internal consistency, test-retest reliability, content validity, and convergent validity of the CVFI were examined, and discriminatory ability (diagnostic accuracy) for distinguishing between the groups was evaluated.

RESULTS

Results showed high internal consistency (Cronbach's alpha ≥ .8817 for the total CVFI scores for all groups), high test-retest reliability (intraclass correlation coefficients ≥ .9072, p < .001 for the total CVFI scores for all groups), high content validity (total content validity index = 0.9368), and high convergent validity (Pearson r ≥ .8155, p < .001 between the total CVFI scores and Factors 1 and 2 scores). Significant differences between the three groups were found in all scores. Receiver operating characteristic analysis revealed a high diagnostic accuracy for distinguishing between the disorders group and the normal group (area under the curve ≥ 0.927, p < .001 for the total CVFI scores and Factors 1 and 2 scores), with cutoff scores of ≥ 36 (total CVFI score), ≥ 23.5 (Factor 1 score), ≥ 7.5 (Factor 2 score), and ≤ 6.5 (Factor 3 score).

CONCLUSIONS

These findings suggested that the CVFI could be a reliable and valid self-assessment tool for the clinical evaluation of vocal fatigue in Mandarin Chinese-speaking populations. A full-scale validation study of the CVFI is recommended to verify these results.

Laying the Groundwork to Study the Heterogeneous Nature of Vocal Fatigue

Vocal fatigue has remained an elusive construct-despite its significant impact on communication, vocation, and quality of life. Current frameworks define vocal fatigue in the context of vocal demands and vocal demand-responses. However, the impact of factors like individuals' baseline vocal fitness and perception of the demand are not well understood. What is also not well understood are the effects of specific vocal demand ingredients on an individual's vocal demand responses. Furthermore, current outcome measures utilized to capture vocal fatigue lack sensitivity and underlying mechanisms are poorly understood. These gaps have led to inconclusive next steps in how to best define, assess, monitor, and manage vocal fatigue. A conceptual framework is needed to study and better understand vocal fatigue constructs. Such a framework should consider the individual's baseline physiology, psychology, key vocal demand ingredients, and biophysiological mechanisms underlying demand responses. The objective of this paper is to help the reader better understand the complex and heterogeneous nature of vocal fatigue and its impact on reliable assessment and monitoring. Future studies will require better elucidation of vocal demand ingredients, will need more sensitive vocal demand response measures, and will need to take in to account an individual's baseline physiology and psychological factors.

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.

Daily Phonotrauma Index: An Objective Indicator of Large Differences in Self-Reported Vocal Status in the Daily Life of Females With Phonotraumatic Vocal Hyperfunction

PURPOSE

The purpose of this study is to evaluate if the Daily Phonotrauma Index (DPI) can quantitatively discriminate large differences in overall vocal status in the daily life of patients with phonotraumatic vocal hyperfunction (PVH).

METHOD

For 1-4 weeks, 23 females with PVH wore an ambulatory voice monitor and answered three vocal status questions (i.e., difficulty producing soft, high-pitched phonation; discomfort; and fatigue) at the beginning, at 5-hr intervals, and the end of each day. DPI values were obtained for each patient's time periods of worst and best self-rated vocal status, and data for the group were analyzed for significant changes using a linear mixed-effects regression model.

RESULTS

The DPI was significantly lower during periods self-rated as "best vocal status" compared to during periods self-rated as "worst vocal status" (mean difference in DPI = 0.53) with a medium-to-large effect size (Cohen's d = -0.68).

CONCLUSIONS

In a group of patients with phonotraumatic lesions, the DPI indicated lower potential for phonotrauma during time periods of better vocal status compared to time periods of worse vocal status. Assuming that a large portion of variance in vocal status for patients with PVH is associated with the extent to which voicing is phonotraumatic, these results support the validity of obtaining estimates of DPI for much shorter time periods (i.e., an estimate every 2 min of voicing) than previous studies (i.e., a single estimate for the entire day or week). Future work can investigate the DPI's use for in-clinic assessment/treatment and ambulatory biofeedback and can gain further insights into phonatory mechanisms that underlie DPI via comparisons with other physiologically relevant measures and computational vocal fold modeling.

Mitigating the Effects of Acute Vocal Exertion in Individuals With Vocal Fatigue

OBJECTIVES/HYPOTHESIS

To investigate the effects of acute vocal exertion on individuals with vocal fatigue and to determine whether semi-occluded vocal tract exercises (SOVTEs) are more effective than vocal rest in mitigating acute effects.

STUDY DESIGN

Prospective, repeated-measures design.

METHODS

On consecutive days, 10 individuals (6 males, 4 females) with scores indicating vocal fatigue on the Vocal Fatigue Index completed two 10-minute vocal exertion tasks. Vocal rest or SOVTEs were interspersed in counterbalanced order between exertion tasks. Respiratory kinematic, acoustic, aerodynamic, and self-perceptual measures were collected at baseline, following vocal exertion, following SOVTE/vocal rest, and following the second exertion task.

RESULTS

Acute vocal exertion worsened phonation threshold pressure (P < .001) and vocal effort (P < .001) and reduced maximum fundamental frequency (P < .001). Speech was terminated at lower lung volumes following vocal exertion (decreased lung volume termination [LVT], P < .001). Exertion-induced changes in vocal effort and LVT were significantly reversed by both vocal rest and SOVTE. Detrimental changes in voice measures reoccurred following the second vocal exertion task. SOVTE and vocal rest protected against changes in respiratory kinematics when vocal exertion was resumed.

CONCLUSIONS

Vocal exertion impacted laryngeal, respiratory, and self-perceptual measures in individuals with vocal fatigue. Both SOVTE and vocal rest partially mitigated changes in voice measures and prompted more efficient respiratory strategies that were maintained when vocal exertion resumed. These data increase our understanding of how individuals with vocal fatigue respond to vocal exertion tasks and offer preliminary guidance for optimal clinical recommendations.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:2732-2739, 2021.

Restoration Strategies Following Short-Term Vocal Exertion in Healthy Young Adults

Purpose This study aims to investigate the effects of a 10-min vocal exertion task on voice and respiratory measures, to determine whether restorative strategies can mitigate these effects after cessation of exertion, and to assess whether these strategies continue to reduce these detrimental effects when vocal exertion is resumed. Method A prospective, repeated-measures design was used. On consecutive days, 20 participants (equal men and women) completed two vocal exertion tasks separated by 10 min of restoration strategies: vocal rest or controlled phonation (low-level tissue mobilization using straw phonation). Voice and respiratory data were collected at baseline, following the first exertion task, after restoration strategies, and after the second exertion task. Outcome measures included (a) vocal effort, (b) phonation threshold pressure, (c) maximum and minimum fundamental frequencies, (d) cepstral peak prominence of connected speech, (e) lung volume initiation and termination, (f) percent vital capacity expended per syllable, and (g) number of syllables per breath group. Results A worsening of phonation threshold pressure (p < .001), vocal effort (p < .001), and increase of minimum fundamental frequency (p = .007) were observed after vocal exertion. Lung volume initiation (p < .001) and lung volume termination (p < .001) increased. These changes were largely reversed by restoration strategies, but only controlled phonation prevented exertion-induced changes in respiratory kinematic measures on a subsequent vocal exertion task. Conclusions Exertion-induced voice changes occur rapidly and may be mitigated by either controlled phonation or vocal rest. Controlled phonation is recommended as a superior strategy due to evidence of a protective effect on a successive vocal exertion task.

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.

Vibrational Therapies for Vocal Fatigue

BACKGROUND

Vibration is commonly used to relax tension in the limb and truck muscle. Vibration used directly on the muscle concerned and vertical vibration used on the whole-body through a foot platform have been reported in the literature to be useful to release muscle tension.

AIM

The present study investigated the effect of indirect whole-body vibration (WBV) and direct localized perilaryngeal vibration (LPV) on the phonatory functions of nondysphonic individuals with vocal fatigue.

METHODS

Forty-four subjects (mean age = 21.67 years) with normal voice, were randomly assigned to either the WBV group, the LPV group, or the Control (sham hand-held vibratory device) group. They performed karaoke singing for at least 95 minutes. They then received either WBV through a Turbosonic vibratory machine, LPV with a Novofan vibrator, or a sham vibrator for 10 minutes. The highest pitch produced, and self-reported vocal fatigue score were taken before singing, after singing, and after the intervention. Data were analyzed separately for the gender subgroups.

RESULTS

All subject groups showed significant reduction of vocal function (highest pitch production, and vocal fatigue score) after singing. Following the vibrational interventions, both the WBV and LPV groups showed significantly recovery in the highest pitch production and the perception of vocal fatigue (P < 0.002) than the Control groups.

CONCLUSION

Vibrational therapy, whether it is localized vibration on the peri-laryngeal muscles, or whole-body vibration, is more effective than voice rest per se in relieving vocal fatigue. Vibrational methods are recommended for treating vocal fatigue.

Continuous Vocal Fry Simulated in Laboratory Subjects: A Preliminary Report on Voice Production and Listener Ratings

PURPOSE

Vocal fry is prevalent in everyday speech. However, whether the use of vocal fry is detrimental to voice production is unclear. This preliminary study assessed the effects of using continuous vocal fry on voice production measures and listener ratings.

METHOD

Ten healthy individuals (equal male and female, mean age = 22.4 years) completed 2 counterbalanced sessions. In each session, participants read in continuous vocal fry or habitual voice quality for 30 min at a comfortable intensity. Continuous vocal fry was simulated. Phonation threshold pressure (PTP10 and PTP20), cepstral peak prominence, and vocal effort ratings were obtained before and after the production of each voice quality. Next, 10 inexperienced listeners (equal male and female, mean age = 24.1 years) used visual analog scales to rate paired samples of continuous vocal fry and habitual voice quality for naturalness, employability, and amount of listener concentration.

RESULTS

PTP10 and vocal effort ratings increased after 30 min of continuous vocal fry. Inexperienced listeners rated continuous vocal fry more negatively than the habitual voice quality.

CONCLUSIONS

Thirty minutes of simulated, continuous vocal fry worsened some voice measures when compared with a habitual voice quality. Samples of continuous vocal fry were rated as significantly less employable, less natural, and requiring greater listener concentration as compared with samples of habitual voice quality. Future studies should include habitual users of vocal fry to investigate speech stimulability and adaptation with cueing to further understand pathogenesis of vocal fry.

Sense of Effort and Fatigue Associated With Talking After Total Laryngectomy

PURPOSE

Sense of effort and fatigue associated with talking was compared in individuals with and without a total laryngectomy.

METHOD

An online survey of individuals using tracheoesophageal speech (TES; n = 222), electrolaryngeal speech (ELS; n = 132), esophageal speech (n = 41), and laryngeal speech (LS; n = 112) asked about 3 domains of effort when talking: frequency of occurrence, withdrawal from talking, and location in the body. Three aspects of fatigue were explored: frequency of occurrence, fatigue type, and duration of talking before fatigue.

RESULTS

Alaryngeal groups reported significantly more talking-related effort and fatigue than the LS group. Sixty-three percent of all respondents indicated that effort caused them to talk less, with no group differences on this item. Significantly more effort was localized to the lips and tongue by ELS compared with TES and LS groups. Both the ELS and TES groups had higher shoulder/arm effort when talking compared with the esophageal speech and LS groups. ELS respondents reported less fatigue than the TES group. When fatigue was present, the TES group had more physical and less mental fatigue than the ELS group. The duration of talking before experiencing fatigue was significantly shorter for the alaryngeal groups compared with the LS group.

CONCLUSIONS

Effort and fatigue associated with talking are a common report for individuals using alaryngeal speech. The location of effort within the body and the type of fatigue experienced vary to some extent across alaryngeal speaking methods.

A feasibility study on non-invasive oxidative metabolism detection and acoustic assessment of human vocal cords by using optical technique

Voice disorder such as vocal fatigue is a common and complex multifaceted clinical problem that presents a significant impact on quality of life. In this study, the functional near-infrared diffuse optical technique (fNIRS-DOT) was proposed as a novel approach for human vocal cords oxidative metabolism detection and acoustic assessment simultaneously to provide a multidimensional assessment of voice disorder. A totally of 60 healthy subjects included 30 male and 30 female adults of age-matched were recruited and performed a vocal loading task to trigger a mild inflammation of the vocal cords in this study. In the results of oxidative metabolism, the vocal cords expressed hypoxia after vocal loading task in both male and female groups that could provide relevant information on the relationship between tissue oxygen consumption and supply for vocal cords diagnosis. Additionally, the results of optical acoustic assessment revealed the worse/changes voice quality after vocal loading task. Therefore, integration of non-invasive oxidative metabolism detection and acoustic assessment by using optical technique could provide more relevant information for diagnosis of voice disorders. The multi-functional vocal cords detection system could provide a good feasibility for clinical applications such as diagnosis and therapeutic monitoring of voice disorder.

Videokymographic Visualization of Phonasthenia: A Nonorganic Voice Disorder

BACKGROUND

Phonasthenia is a voice disorder where the larynx looks essentially normal and dysphonia is not heard but felt by the patient. This study aims to use videokymography (VKG) to detect any abnormalities in the vibratory pattern in phonasthenia and to find out whether or not these abnormalities change after vocal loading.

METHODS

Thirty-seven phonasthenic patients and 31 normal subjects participated in a detailed protocol, including analysis of subjective complaints and videokymographic quasi-objective parameters (baseline) followed by loading their voices through prolonged loud reading for 45 min. A second evaluation (experimental) was done after loading.

RESULTS

Before vocal loading, patients had significantly more symptoms in all questionnaire questions and higher maximum width difference in VKG than controls. When pre- and postloading values were compared, both groups experienced more symptoms after loading (significant in most of the questions), while the pre- and post-VKG parameters did not show significant differences neither in patients nor controls. On comparing their percent change, the only statistically significant difference between the 2 groups was a greater change in the total score of the questionnaire in the control group.

CONCLUSION

Patients had more vocal fatigue symptoms and more amplitude asymmetry between left and right vocal folds than normal subjects.

Self-Ratings of Vocal Status in Daily Life: Reliability and Validity for Patients With Vocal Hyperfunction and a Normative Group

PURPOSE

The aim of this study was to establish reliability and validity for self-ratings of vocal status obtained during the daily activities of patients with vocal hyperfunction (VH) and matched controls.

METHOD

Eight-four patients with VH and 74 participants with normal voices answered 3 vocal status questions-difficulty producing soft, high-pitched phonation (D-SHP); discomfort; and fatigue-on an ambulatory voice monitor at the beginning, 5-hr intervals, and the end of each day (7 total days). Two subsets of the patient group answered the questions during a 2nd week after voice therapy (29 patients) or laryngeal surgery (16 patients).

RESULTS

High reliability resulted for patients (Cronbach's α = .88) and controls (α = .95). Patients reported higher D-SHP, discomfort, and fatigue (Cohen's d = 1.62-1.92) compared with controls. Patients posttherapy and postsurgery reported significantly improved self-ratings of vocal status relative to their pretreatment ratings (d = 0.70-1.13). Within-subject changes in self-ratings greater than 20 points were considered clinically meaningful.

CONCLUSIONS

Ratings of D-SHP, discomfort, and fatigue have adequate reliability and validity for tracking vocal status throughout daily life in patients with VH and vocally healthy individuals. These questions could help investigate the relationship between vocal symptom variability and putative contributing factors (e.g., voice use/rest, emotions).

Respiratory and Laryngeal Changes With Vocal Loading in Younger and Older Individuals

PURPOSE

The objective of the current study was to investigate the effects of age and vocal loading on the respiratory and laryngeal systems.

METHOD

Fourteen younger (M = 20 years) and 13 older (M = 75 years) healthy individuals participated in a 40-min vocal loading challenge in the presence of 70-dB background noise. Respiratory kinematic and laryngeal measurements were obtained before and after the challenge.

RESULTS

Following the loading challenge, participants in both groups reported greater speaking effort. Sound pressure level increased in the older group and decreased in the younger group after loading. Younger adults, but not older adults, used lower lung volume initiations and higher lung volume terminations after loading. Cepstral peak prominence increased with loading in both groups, but this change was of small magnitude and not clinically significant.

CONCLUSIONS

The negative effects of loading were observed in respiratory and laryngeal measures, although the pattern of changes differed across the groups. These data increase our knowledge of underlying respiratory and laryngeal physiological changes following a loading challenge and may reflect some of the physiologic mechanisms underlying vocal fatigue.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Phonatory function after prolonged voice use in Brazilian woman

OBJECTIVES

To evaluate the behavior of the phonatory function and the perceived strain in Brazilian young women, before and after a test of prolonged voice use test, for a period of one continuous hour.

METHODS

Twenty young women without laryngeal disorders participated in the study and were submitted to vocal acoustic analysis (MDVP-Advanced, CSL-Kay Pentax®), perceptual voice assessment, carried out by five judges, and the measurement of speech-strain level using a visual analog scale before and after a prolonged use of the voice, from the reading of a standardized text for one hour in usual vocal intensity and frequency, without breaks for hydration or vocal rest. The description and comparison between the variables and the appropriate statistical analysis were carried out.

RESULTS

The acoustic parameters of fundamental (f0) and low frequency (Flo) of the emission increased after 1 hour of voice use, while the values for the amplitude tremor intensity index (Atri), amplitude variation (vAm), noise-to-harmonic ratio (NHR), and soft phonation index (SPI) were reduced after the prolonged voice use test. The judges agreed with the decrease in the overall level of dysphonia (kappa=0.66), roughness (kappa=0.59), and vocal breathiness (kappa=0.73); increased phonatory stability (kappa=0.64); vocal projection (kappa=0.48); pitch (kappa=0.74); and loudness (kappa=0.65). The phonatory strain increased significantly after the test (p=0.003).

CONCLUSION

One hour of prolonged voice use seems to favor laryngeal adaptation and increased adductor muscle activity to maintain vocal efficiency. However, the self-perception of vocal strain is evident and can be understood as a sign of muscle fatigue caused by continuous use.

Uso do programa MDVP em diferentes contextos: revisão de literatura

Resumo:Este estudo tem como objetivo descrever, a partir de revisão de literatura, a confiabilidade da análise acústica utilizando o Multi Dimensional Voice Program,comparação de suas medidas com outros programas de análise acústica; caracterização de vozes de diferentes grupos; e sua utilização para verificar os efeitos e eficácia de diferentes procedimentos terapêuticos. Realizou-se levantamento bibliográfico que priorizaram estudos dos últimos cinco anos, incluindo-se artigos cujo objetivo estivesse de acordo com o interesse da presente revisão. A pesquisa foi realizada nos bancos de dados das bases Lilacs, BIREME, PubMed, MedLine, Scielo e Google Schoolar, por meio dos descritores acoustic, speech acoustics e voice. As medidas mais utilizadas são frequência fundamental, jitter, shimmer e proporção harmônico-ruído. As medidas de tremor não apresentam boa confiabilidade. As medidas mais consistentes que apresentam alta concordância com outros programas de análise acústica são as relacionadas com a frequência fundamental. Diversos estudos buscam caracterizar diferentes tipos de vozes tais como as de sujeitos sem alterações vocais de ambos os sexos, buscando estabelecer parâmetro de normalidade para diferentes grupos populacionais. Além disso, alguns estudos caracterizam vozes com diferentes distúrbios. A análise acústica é um recurso objetivo e necessário na avaliação de pacientes com distúrbio vocal e, principalmente, na comparação de diversos tipos de tratamento.

Comparison of vocal loading parameters in kindergarten and elementary school teachers

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

Voice outcome in patients treated for laryngeal cancer: efficacy of voice rehabilitation

OBJECTIVE

To investigate the efficacy of voice rehabilitation regarding acoustically measured voice quality as well as self-perceived function after radiotherapy for laryngeal cancer.

STUDY DESIGN

Prospective intervention study.

METHODS

Twenty male patients irradiated for laryngeal cancer participated in the study. Voice recordings and self-assessment of voice function (hoarseness, vocal fatigue, and vocal loudness) were made one and 6 months after completion of radiotherapy. The recordings were analyzed with the program Praat. Ten of the patients received 10 sessions of structured voice rehabilitations between the recordings and 10 worked as a control group.

RESULTS

Jitter and shimmer improved for both groups. Harmonics-to-noise-ratio and maximum phonation time improved for the patients who received voice rehabilitation while it deteriorated for the control group. The self-assessment questions about vocal fatigue and vocal loudness showed improvement for both groups while hoarseness showed no change.

CONCLUSION

General improvement was seen for both the study group and the control group. Despite the lack of statistical significant difference, there are trends where greater improvement in perturbation and self-assessment measures are noted in the study group. The results suggest positive effects of voice rehabilitation in both voice quality and self-perceived function.