Aerodynamic and acoustic features of vocal effort

Singing In The Mask: Effects Of A Variably Occluded Face Mask On Singing

OBJECTIVE

A limitation of traditional semi-occluded vocal tract exercises (SOVTE) is the single sustained vowel task that precludes co-articulated singing. This study investigated immediate effects of a variably occluded face mask (VOFM) on vocal effort, acoustic, and aerodynamic measures in sung low and high pitches of healthy singers.

DESIGN

Single-group, pre-post intervention study.

METHODS

The outlet ports of disposable anesthesia facemasks were fitted with plastic caps with two drilled openings sizes (9.6 mm, 6.4 mm). Twenty-three singers with no voice complaints provided baseline vocal effort, acoustic, and aerodynamic measures in high and low pitches. Participants trained in four conditions: two VOFM sizes (9.6 mm, 6.4 mm) in combination with the 20th and 80th percentile of the singer's pitch range. Participants were trained on three phonatory tasks: repeated consonant/vowel syllables, sung sentence, and sustained vowel. Vocal effort before and after training was compared using a visual-analog scale, while standardized mean differences captured acoustic and aerodynamic changes before and after training.

RESULTS

Participants reported decreased vocal effort after VOFM training at all occlusion and pitch combinations. On average, consistent beneficial effect sizes were found in cepstral peak prominence (CPP) and cepstral spectral index of dysphonia (CSID) for all 4 occlusion-pitch combinations, and vocal intensity and mean estimated subglottal pressure increased for all 4 occlusion-pitch training combinations. Changes in mean phonatory airflow and resistance were less consistent.

DISCUSSION

There was an immediate effect of decreased vocal effort in singing after VOFM training. Acoustic and aerodynamic effects were variable and modest. Future studies should explore changes in these outcomes after VOFM in singing voice therapy.

Acoustic and Physiologic Correlates of Vocal Effort in Individuals With and Without Primary Muscle Tension Dysphonia

OBJECTIVES

The aims of this study were to determine relationships between vocal effort and (a) acoustic correlates of vocal output and (b) supraglottic compression in individuals with primary muscle tension dysphonia (pMTD) and without voice disorders (controls) in the context of a vocal load challenge.

METHOD

Twenty-six individuals with pMTD and 35 vocally healthy controls participated in a 30-min vocal load challenge. The pre- and postload relationships among self-ratings of vocal effort, various acoustic voice measures, and supraglottic compression (mediolateral and anteroposterior) were tested with multiple regression models and post hoc Pearson's correlations. Acoustic measures included cepstral peak prominence (CPP), low-to-high spectral ratio, difference in intensity between the first two harmonics, fundamental frequency, and sound pressure level (dB SPL).

RESULTS

Regression models for CPP and mediolateral compression were statistically significant. Vocal effort, diagnosis of pMTD, and vocal demand were each significant variables influencing CPP measures. CPP was lower in the pMTD group across stages. There was no statistical change in CPP following the vocal load challenge within either group, but both groups had an increase in vocal effort postload. Vocal effort and diagnosis influenced the mediolateral compression model. Mediolateral compression was higher in the pMTD group across stages and had a negative relationship with vocal effort, but it did not differ after vocal loading.

CONCLUSIONS

CPP and mediolateral supraglottic compression were influenced by vocal effort and diagnosis of pMTD. Increased vocal effort was associated with lower CPP, particularly after vocal load, and decreased mediolateral supraglottic compression in the pMTD group.

Breathing better: A tech-monitored study of positive expiratory pressure and reading aloud for chronic obstructive pulmonary disease

BACKGROUND

Breathing exercises, such as diaphragmatic breathing and positive expiratory pressure (PEP), relieve breathlessness in people with chronic obstructive pulmonary disease (COPD).

AIM

This study aimed to investigate the effects of breathing exercises with PEP and reading aloud on vital signs, fatigue level, severity of dyspnoea and respiratory function parameters in patients with COPD.

DESIGN

The study followed a randomized controlled trial of COPD patients from a single hospital in eastern Turkey.

METHODS

The study included 103 patients who were randomly assigned to receive pre-reading exercises, breathing exercises with a PEP device or no intervention for 8 weeks.

RESULTS

The use of a PEP device improved oxygen saturation, forced expiratory volume in 1 s (FEV1 ) and FEV1 /forced vital capacity (FVC) values and reduced fatigue and dyspnoea severity. Reading aloud lowered the mean arterial pressure and reduced fatigue and dyspnoea severity.

CONCLUSION

The study concludes that PEP devices and reading aloud can improve respiratory function in patients with COPD. Additionally, reading aloud is an accessible, easy-to-implement and economically feasible method for treating COPD symptoms.

Initial Theoretical Discussion of Identity as Barrier and Facilitator in Voice Habilitation and Rehabilitation

OBJECTIVES

The purpose of this paper is to review seminal identity theories grounded in social psychology and one concept from voice science and explain how this group may point to identity factors facilitating or impeding voice habilitation and rehabilitation.

METHODS

Identity theories from the social psychology literature (Dramaturgical Theory, Self-Categorization Theory, Self-Determination Theory, Identity Negotiation Theory) and vocal congruence are described. Concepts are synthesized with voice science research to explore potential identity-behavior relations at play in voice habilitation and rehabilitation.

RESULTS

Applicable concepts from social psychology and voice science suggest identity-related processes by which a client may or may not develop a voice difference/disorder, seek intervention, and achieve goals in intervention. A bidirectional relationship between identity and behavior has been well-established in the social psychology literature. However, the relevance of vocal behavior has yet to be formally examined within this literature. Importantly, although connections between behavioral tendencies and voice disorders as well as the contribution of identity to gender-affirming voice treatment have been established in the voice science literature, the consideration of identity's possible role in voice habilitation and rehabilitation in cis gender individuals has thus far been scant.

CONCLUSIONS

Research into identity and voice habilitation and rehabilitation may help to improve voice intervention outcomes. A possible adjunct to human studies is agent-based modeling or other computational approaches to assess the myriad factors that may be relevant within this line of inquiry.

Effect of Face Masks and Speech Style on Speech Intelligibility and Listener Effort in Parkinson's Disease

PURPOSE

The aim of this study was to quantify the combined effects of face masks and effortful speech styles on listener intelligibility and perceived listener effort in talkers with and without Parkinson's disease (PD).

METHOD

Ten people with PD and 10 healthy, older controls read aloud sentences in two face mask and three speech style conditions. Masks included no mask and KN95 masks. Speech styles included habitual, clear, and loud. Listener participants were tasked with listening to each sentence mixed with background noise and then transcribing what they heard and rating how effortful it was to understand. Listener accuracy and effort were each modeled as a function of speaker group, face mask, and speech style using mixed-effects regression models.

RESULTS

Listeners were less accurate and reported greater listening effort for the PD group and for the mask condition. Listeners were more accurate and reported less effort when listening to clear and loud compared to habitual speech. Listener accuracy and listener effort were strongly negatively correlated across all conditions. Face masks were also associated with a steeper decline in speech intelligibility and an increase in listener effort for talkers with PD.

DISCUSSION

Face masks resulted in steeper speech intelligibility decline for talkers with PD compared to controls. Speaking more loudly or more clearly when wearing a face mask improved intelligibility for talkers with PD compared to habitual speech, and both speech styles resulted in speech intelligibility levels that approximated talkers' baseline intelligibility levels without a mask.

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.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Impact of naturalistic smartphone positioning on acoustic measures of voicea)

Smartphone technology has been used for at-home health monitoring, but there are few available applications (apps) for tracking acoustic measures of voice for those with chronic voice problems. Current apps limit the user by restricting the range of smartphone positions to those that are unnatural and non-interactive. Therefore, we aimed to understand how more natural smartphone positions impacted the accuracy of acoustic measures in comparison to clinically acquired and derived measures. Fifty-six adults (11 vocally healthy, 45 voice disordered, aged 18-80 years) completed voice recordings while holding their smartphones in four different positions (e.g., as if reading from the phone, up to the ear, etc.) while a head-mounted high-quality microphone attached to a handheld acoustic recorder simultaneously captured voice recordings. Comparisons revealed that mean fundamental frequency (Hz), maximum phonation time (s), and cepstral peak prominence (CPP; dB) were not impacted by phone position; however, CPP was significantly lower on smartphone recordings than handheld recordings. Spectral measures (low-to-high spectral ratio, harmonics-to-noise ratio) were impacted by the phone position and the recording device. These results indicate that more natural phone positions can be used to capture specific voice measures, but not all are directly comparable to clinically derived values.

Tracking Occupational Voice State with a Visual Analog Scale: Voice Quality, Vocal Fatigue, and Effort

BACKGROUND

Due to elevated vocal health risk in industries such as call centers, there is a need to have accessible and quick self-report tools for voice symptoms. This study aimed to determine if the concurrent and construct validity of three visual analog scales (VASs) of voice quality and symptoms could be used as a screening tool in call center agents.

METHODS

A cross-sectional study was carried out in three call center companies. The Voice Handicap Index-10 (VHI-10) and a vocal hygiene and symptoms survey were administered to 66 call center workers. Further, acoustic parameters including harmonics-to-noise ratio (HNR), smoothed cepstral peak prominence (CPPs), L1-L0 slope, and Alpha ratio were collected. Finally, workers completed three VASs capturing self-perception of vocal effort (VAS-1), voice quality (VAS-2), and vocal fatigue (VAS-3). Linear regression models with bootstrapping evaluated the possible relationship between the three VASs measurements, self-perceived vocal symptoms, and acoustic parameters.

RESULTS

VAS-1 scores were associated with HNR and voice breaks, VAS-2 with voice breaks, and VAS-3 with Alpha ratio. Using the area under a receiver operating characteristic curve (AUC), the highest AUC for detecting an altered VHI-10 questionnaire score was observed for the three VASs. Also, the highest AUC for detecting altered CPPs was reached for the VAS-1.

CONCLUSIONS

VAS as a self-report instrument of vocal symptoms is related to psychosocial voice impairment and alterations of acoustic voice parameters in call center workers. Such instruments could be easily implemented to identify voice complaints in these populations.

LEVEL OF EVIDENCE

2 (Diagnosis research question) Laryngoscope, 133:1676-1682, 2023.

Examining Relationships Between GRBAS Ratings and Acoustic, Aerodynamic and Patient-Reported Voice Measures in Adults With Voice Disorders

OBJECTIVE

To determine if auditory-perceptual voice ratings performed using the GRBAS scale correlate with acoustic and aerodynamic measures of voice. A secondary aim was to examine the relationship between GRBAS ratings and patient-reported quality of life scales.

METHODS

GRBAS ratings, acoustic, aerodynamic and patient-reported quality of life ratings were collected from the University of Wisconsin Madison Voice and Swallow Outcomes Database for 508 adults with voice disorders. Acoustic measures included noise to harmonic ratio, jitter%, shimmer%, highest fundamental frequency (F0) of vocal range, lowest F0 of vocal range, maximum phonation time and dysphonia severity index. Aerodynamic measures included phonation threshold pressure, subglottal pressure, mean transglottal airflow and laryngeal airway resistance. Patient-reported quality of life measures included the Vocal Handicap Index (VHI) and Glottal Function Index (GFI).

RESULTS

GRBAS ratings were significantly correlated with several acoustic and aerodynamic measures, VHI and GFI. The strongest significant correlations for acoustic measures were observed between GRBAS ratings of overall voice quality and perturbation measures (jitter% r = 0.58, shimmer% r = 0.45, noise to harmonic ratio r = 0.36, Dysphonia Severity Index r = -0.56). The strongest significant correlation for aerodynamic voice measures was observed between GRBAS ratings of breathiness and transglottal airflow (r = 0.23), subglottal pressure (r = 0.49), and phonation threshold pressure (r = 0.26). GRBAS ratings were also significantly correlated with both VHI and the GFI scales. R values were higher for the VHI, but remained largely in low range for both scales.

CONCLUSIONS

Although GRBAS ratings were significantly correlated with multiple objective voice and patient related quality of life ratings, r values were low. These findings support the need for multiple voice measures when performing voice evaluations as no single voice measure was highly correlated with voice quality as measured by the GRBAS scale.

Auditory-perceptual Parameters as Predictors of Voice Acoustic Measures

BACKGROUND

Much research has examined the relationship between perceptual and acoustic measures. However, little is known about the prediction values of perceptual measures on an acoustic parameter.

AIMS

This study utilized simulated and disordered voice samples to investigate the prediction values of breathiness, roughness, and strain ratings on the selection of some time-based and spectral-based measures of voice quality.

METHOD

This study retrospectively analysed two sets of precollected data. The experimental data had been collected from nine trained speakers manipulating false vocal fold activity, true vocal fold mass, and larynx height. The voice-disordered data had been extracted from a clinical database for 68 patients with muscle tension voice disorders (MTVD). Both data sets had been perceptually rated for breathiness, roughness, and strain. Voice samples (prolonged vowel /ɑ/ and Rainbow Passage readings) had undergone acoustic analysis using Praat for harmonics-to-noise ratio (HNR) and the program "Analysis of Dysphonia in Speech and Voice" (ADSV) for cepstral peak prominence (CPP), Cepstral/Spectral Index of Dysphonia (CSID), and Low/High spectral ratio (L/H ratio). Perceptual parameters were regressed against these acoustic measures to test their prediction values.

RESULTS

Reliability data showed satisfactory intra- and inter-reliability of perceptual ratings for both data sets. Breathiness significantly predicted CPP (both vocal tasks) and CSID (Rainbow Passage) in experimental data and predicted all the acoustic measures in MTVD data. Roughness significantly predicted HNR, CPP, and CSID in experimental data, and CPP (Rainbow Passage) and CSID (both vocal tasks) in MTVD data. Strain (both vocal tasks) significantly predicted L/H ratio in both data sets.

CONCLUSIONS

Breathiness ratings predicted selection of HNR, CPP and CSID; roughness ratings predicted selection of CPP and CSID, and strain ratings predicted L/H ratio.

Relationship Between Auditory-Perceptual and Objective Measures of Resonance in Children with Cleft Palate: Effects of Intelligibility and Dysphonia

To investigate the relationship between auditory-perceptual ratings of resonance and nasometry scores in children with cleft palate. Factors which may impact this relationship were examined including articulation, intelligibility, dysphonia, sex, and cleft-related diagnosis.

Retrospective, observational cohort study.

Outpatient pediatric cranio-facial anomalies clinic.

Four hundred patients <18 years of age identified with CP ± L, seen for auditory-perceptual and nasometry evaluations of hypernasality as well as assessments of articulation and voice.

Relationship between auditory-perceptual ratings of resonance and nasometry scores.

Pearson's correlations indicated that auditory-perceptual resonance ratings and nasometry scores were significantly correlated across oral-sound stimuli on the picture-cued portion of the MacKay-Kummer SNAP-R Test (r values .69 to.72) and the zoo reading passage (r = .72). Linear regression indicated that intelligibility (p ≤ .001) and dysphonia (p = .009) significantly impacted the relationship between perceptual and objective assessments of resonance on the Zoo passage. Moderation analyses indicated that the relationship between auditory-perceptual and nasometry values weakened as severity of speech intelligibility increased (P < .001) and when children presented with moderate dysphonia (p ≤ .001). No significant impact of articulation testing or sex were observed.

Speech intelligibility and dysphonia alter the relationship between auditory-perceptual and nasometry assessments of hypernasality in children with cleft palate. SLPs should be aware of potential sources of auditory-perceptual bias and shortcomings of the Nasometer when following patients with limited intelligibility or moderate dysphonia. Future study may identify the mechanisms by which intelligibility and dysphonia affect auditory-perceptual and nasometry evaluations.

Singing Voice Concern in Tertiary Laryngology Practice

OBJECTIVES

To determine the prevalence and characteristics of patients who identify singing voice as a primary concern when presenting with general voice complaints to a voice clinic.

METHODS

Data were collected from medical records on demographics, medical history, laryngoscopy exam, diagnosis, and subsequent treatments; and from self-report questionnaires including the Voice Handicap Index-10 (VHI-10) and clinical voice questionnaire.

RESULTS

A total of 17% of patients presenting to a voice clinic with general voice problems who completed a VHI-10 identified singing voice as a primary concern. Compared to the reference cohort, patients concerned about singing voice report greater handicap on several questions of the VHI-10, particularly in personal and social life impact, loss of income, unpredictability of vocal clarity, subjective upset, and subjective handicap. Those concerned with singing voice were also more concerned about their vocal problem, and both more likely to be recommended voice therapy and participate in voice therapy despite no statistical differences in categorical diagnoses.

CONCLUSIONS

When considering both professional and recreational singers, voice concerns occurred in 17% of the cohort under study. Patients with singing voice concerns are accounted for largely by recreational singers, who remain poorly characterized in the literature. We underscore the importance of sensitivity and responsivity to the needs of this group of patients.

Ambulatory Monitoring of Subglottal Pressure Estimated from Neck-Surface Vibration in Individuals with and without Voice Disorders

The aerodynamic voice assessment of subglottal air pressure can discriminate between speakers with typical voices from patients with voice disorders, with further evidence validating subglottal pressure as a clinical outcome measure. Although estimating subglottal pressure during phonation is an important component of a standard voice assessment, current methods for estimating subglottal pressure rely on non-natural speech tasks in a clinical or laboratory setting. This study reports on the validation of a method for subglottal pressure estimation in individuals with and without voice disorders that can be translated to connected speech to enable the monitoring of vocal function and behavior in real-world settings. During a laboratory calibration session, a participant-specific multiple regression model was derived to estimate subglottal pressure from a neck-surface vibration signal that can be recorded during natural speech production. The model was derived for vocally typical individuals and patients diagnosed with phonotraumatic vocal fold lesions, primary muscle tension dysphonia, and unilateral vocal fold paralysis. Estimates of subglottal pressure using the developed method exhibited significantly lower error than alternative methods in the literature, with average errors ranging from 1.13 to 2.08 cm H₂O for the participant groups. The model was then applied during activities of daily living, thus yielding ambulatory estimates of subglottal pressure for the first time in these populations. Results point to the feasibility and potential of real-time monitoring of subglottal pressure during an individual's daily life for the prevention, assessment, and treatment of voice disorders.

Lombard Effect in Individuals With Nonphonotraumatic Vocal Hyperfunction: Impact on Acoustic, Aerodynamic, and Vocal Fold Vibratory Parameters

PURPOSE

This exploratory study aims to investigate variations in voice production in the presence of background noise (Lombard effect) in individuals with nonphonotraumatic vocal hyperfunction (NPVH) and individuals with typical voices using acoustic, aerodynamic, and vocal fold vibratory measures of phonatory function.

METHOD

Nineteen participants with NPVH and 19 participants with typical voices produced simple vocal tasks in three sequential background conditions: baseline (in quiet), Lombard (in noise), and recovery (5 min after removing the noise). The Lombard condition consisted of speech-shaped noise at 80 dB SPL through audiometric headphones. Acoustic measures from a microphone, glottal aerodynamic parameters estimated from the oral airflow measured with a circumferentially vented pneumotachograph mask, and vocal fold vibratory parameters from high-speed videoendoscopy were analyzed.

RESULTS

During the Lombard condition, both groups exhibited a decrease in open quotient and increases in sound pressure level, peak-to-peak glottal airflow, maximum flow declination rate, and subglottal pressure. During the recovery condition, the acoustic and aerodynamic measures of individuals with typical voices returned to those of the baseline condition; however, recovery measures for individuals with NPVH did not return to baseline values.

CONCLUSIONS

As expected, individuals with NPVH and participants with typical voices exhibited a Lombard effect in the presence of elevated background noise levels. During the recovery condition, individuals with NPVH did not return to their baseline state, pointing to a persistence of the Lombard effect after noise removal. This behavior could be related to disruptions in laryngeal motor control and may play a role in the etiology of NPVH.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.20415600.

The impact of face masks on spectral acoustics of speech: Effect of clear and loud speech styles

This study quantified the effects of face masks on spectral speech acoustics in healthy talkers using habitual, loud, and clear speaking styles. Harvard sentence lists were read aloud by 17 healthy talkers in each of the 3 speech styles without wearing a mask, when wearing a surgical mask, and when wearing a KN95 mask. Outcome measures included speech intensity, spectral moments, and spectral tilt and energy in mid-range frequencies which were measured at the utterance level. Masks were associated with alterations in spectral density characteristics consistent with a low-pass filtering effect, although the effect sizes varied. Larger effects were observed for center of gravity and spectral variability (in habitual speech) and spectral tilt (across all speech styles). KN95 masks demonstrated a greater effect on speech acoustics than surgical masks. The overall pattern of the changes in speech acoustics was consistent across all three speech styles. Loud speech, followed by clear speech, was effective in remediating the filtering effects of the masks compared to habitual speech.

Impact of Vocal Effort on Respiratory and Articulatory Kinematics

PURPOSE

The goal of this study was to examine the effects of increases in vocal effort, without changing speech intensity, on respiratory and articulatory kinematics in young adults with typical voices.

METHOD

A total of 10 participants completed a reading task under three speaking conditions: baseline, mild vocal effort, and maximum vocal effort. Respiratory inductance plethysmography bands around the chest and abdomen were used to estimate lung volumes during speech, and sensor coils for electromagnetic articulography were used to transduce articulatory movements, resulting in the following outcome measures: lung volume at speech initiation (LVSI) and at speech termination (LVST), articulatory kinematic vowel space (AKVS) of two points on the tongue dorsum (body and blade), and lip aperture.

RESULTS

With increases in vocal effort, and no statistical changes in speech intensity, speakers showed: (a) no statistically significant differences in LVST, (b) statistically significant increases in LVSI, (c) no statistically significant differences in AKVS measures, and (d) statistically significant reductions in lip aperture.

CONCLUSIONS

Speakers with typical voices exhibited larger lung volumes at speech initiation during increases in vocal effort, paired with reduced lip displacements. To our knowledge, this is the first study to demonstrate evidence that articulatory kinematics are impacted by modulations in vocal effort. However, the mechanisms underlying vocal effort may differ between speakers with and without voice disorders. Thus, future work should examine the relationship between articulatory kinematics, respiratory kinematics, and laryngeal-level changes during vocal effort in speakers with and without voice disorders.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.17065457.

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.

The Relationship Between Voice Onset Time and Increase in Vocal Effort and Fundamental Frequency

Purpose Prior work suggests that voice onset time (VOT) may be impacted by laryngeal tension: VOT means decrease when individuals with typical voices increase their fundamental frequency (f o) and VOT variability is increased in individuals with vocal hyperfunction, a voice disorder characterized by increased laryngeal tension. This study further explored the relationship between VOT and laryngeal tension during increased f o, vocal effort, and vocal strain. Method Sixteen typical speakers of American English were instructed to produce VOT utterances under four conditions: baseline, high pitch, effort, and strain. Repeated-measures analysis of variance models were used to analyze the effects of condition on VOT means and standard deviations (SDs); pairwise comparisons were used to determine significant differences between conditions. Results Voicing, condition, and their interaction significantly affected VOT means. Voiceless VOT means significantly decreased for high pitch (p < .001) relative to baseline; however, no changes in voiceless VOT means were found for effort or strain relative to baseline. Although condition had a significant effect on VOT SDs, there were no significant differences between effort, strain, and high pitch conditions relative to baseline. Conclusions Speakers with typical voices likely engage different musculature to increase pitch than to increase vocal effort and strain. The increased VOT variability present with vocal hyperfunction is not seen in individuals with typical voices using increased effort and strain, supporting the assertion that this feature of vocal hyperfunction may be related to disordered vocal motor control rather than resulting from effortful voice production.

Comparing Ensemble-Based Machine Learning Classifiers Developed for Distinguishing Hypokinetic Dysarthria from Presbyphonia

It is essential to understand the voice characteristics in the normal aging process to accurately distinguish presbyphonia from neurological voice disorders. This study developed the best ensemble-based machine learning classifier that could distinguish hypokinetic dysarthria from presbyphonia using classification and regression tree (CART), random forest, gradient boosting algorithm (GBM), and XGBoost and compared the prediction performance of models. The subjects of this study were 76 elderly patients diagnosed with hypokinetic dysarthria and 174 patients with presbyopia. This study developed prediction models for distinguishing hypokinetic dysarthria from presbyphonia by using CART, GBM, XGBoost, and random forest and compared the accuracy, sensitivity, and specificity of the development models to identify the prediction performance of them. The results of this study showed that random forest had the best prediction performance when it was tested with the test dataset (accuracy = 0.83, sensitivity = 0.90, and specificity = 0.80, and area under the curve (AUC) = 0.85). The main predictors for detecting hypokinetic dysarthria were Cepstral peak prominence (CPP), jitter, shimmer, L/H ratio, L/H ratio_SD, CPP max (dB), CPP min (dB), and CPPF0 in the order of magnitude. Among them, CPP was the most important predictor for identifying hypokinetic dysarthria.

The Impact of Communication Modality on Voice Production

Purpose Communicating remotely using audio and audiovisual technology is ubiquitous in modern work and social environments. Remote communication is increasing in medicine and in voice therapy delivery, and this evolution may have an impact on speakers' voices. This study sought to determine whether these communication modalities impact the voice production of typical speakers. Method The speech acoustics of 12 participants with healthy voices were recorded as they held standardized conversations with a single investigator using three communication modalities: in-person, remote-audio, and remote-audiovisual. Participants rated their vocal effort on a 100-mm visual analog scale. Results Compared to in-person communication, self-ratings of vocal effort were statistically significantly increased for remote-audiovisual communication; vocal effort during remote-audio and in-person communication were not significantly different. In comparison to in-person communication, vocal intensity and smoothed cepstral peak prominence (CPPS) were statistically significantly higher during remote-audio and remote-audiovisual communication. Effect sizes for CPPS changes were larger than for sound pressure level (SPL), and changes in CPPS and SPL between in-person and remote-audiovisual communication were not significantly correlated. Conclusions Vocal effort and SPL were increased when using remote-audio and remote-audiovisual communication in comparison to in-person communication. Voice quality was also impacted by technology use, with changes in CPPS that were consistent with, but not fully explained by, increases in SPL. This may impact the telepractice delivery of voice therapy, and further investigation is warranted.

Estimation of Subglottal Pressure From Neck Surface Vibration in Patients With Voice Disorders

Purpose Given the established linear relationship between neck surface vibration magnitude and mean subglottal pressure (Ps) in vocally healthy speakers, the purpose of this study was to better understand the impact of the presence of a voice disorder on this baseline relationship. Method Data were obtained from participants with voice disorders representing a variety of glottal conditions, including phonotraumatic vocal hyperfunction, nonphonotraumatic vocal hyperfunction, and unilateral vocal fold paralysis. Participants were asked to repeat /p/-vowel syllable strings from loud-to-soft loudness levels in multiple vowel contexts (/pa/, /pi/, /pu/) and pitch levels (comfortable, higher than comfortable, lower than comfortable). Three statistical metrics were computed to analyze the regression line between neck surface accelerometer (ACC) signal magnitude and Ps within and across pitch, vowel, and voice disorder category: coefficient of determination (r 2), slope, and intercept. Three linear mixed-effects models were used to evaluate the impact of voice disorder category, pitch level, and vowel context on the relationship between ACC signal magnitude and Ps. Results The relationship between ACC signal magnitude and Ps was statistically different in patients with voice disorders than in vocally healthy controls; patients exhibited higher levels of Ps given similar values of ACC signal magnitude. Negligible effects were found for pitch condition within each voice disorder category, and negligible-to-small effects were found for vowel context. The mean of patient-specific r 2 values was .63, ranging from .13 to .92. Conclusions The baseline, linear relationship between ACC signal magnitude and Ps is affected by the presence of a voice disorder, with the relationship being participant-specific. Further work is needed to improve ACC-based prediction of Ps, across treatment, and during naturalistic speech production.

Improved subglottal pressure estimation from neck-surface vibration in healthy speakers producing non-modal phonation

Subglottal air pressure plays a major role in voice production and is a primary factor in controlling voice onset, offset, sound pressure level, glottal airflow, vocal fold collision pressures, and variations in fundamental frequency. Previous work has shown promise for the estimation of subglottal pressure from an unobtrusive miniature accelerometer sensor attached to the anterior base of the neck during typical modal voice production across multiple pitch and vowel contexts. This study expands on that work to incorporate additional accelerometer-based measures of vocal function to compensate for non-modal phonation characteristics and achieve an improved estimation of subglottal pressure. Subjects with normal voices repeated /p/-vowel syllable strings from loud-to-soft levels in multiple vowel contexts (/ɑ/, /i/, and /u/), pitch conditions (comfortable, lower than comfortable, higher than comfortable), and voice quality types (modal, breathy, strained, and rough). Subject-specific, stepwise regression models were constructed using root-mean-square (RMS) values of the accelerometer signal alone (baseline condition) and in combination with cepstral peak prominence, fundamental frequency, and glottal airflow measures derived using subglottal impedance-based inverse filtering. Five-fold cross-validation assessed the robustness of model performance using the root-mean-square error metric for each regression model. Each cross-validation fold exhibited up to a 25% decrease in prediction error when the model incorporated multidimensional aspects of the accelerometer signal compared with RMS-only models. Improved estimation of subglottal pressure for non-modal phonation was thus achievable, lending to future studies of subglottal pressure estimation in patients with voice disorders and in ambulatory voice recordings.

Hearing Impairment Increases Communication Effort During Conversations in Noise

Purpose This article describes patterns of speech modifications produced by talkers as a function of the degree of hearing impairment of communication partners during naturalistic conversations in noise. An explanation of observed speech modifications is proposed in terms of a generalization of the concept of effort. This account complements existing theories of listening effort by extending the concept of effort to the domain of interactive communication. Method Twenty young adult normal hearing participants and 20 older adult hearing-impaired participants were tested in pairs. Each pair consisted of 1 young normal hearing participant and 1 older hearing-impaired participant. Pairs of participants took part in naturalistic conversations through the use of a referential communication task. Each pair completed a 5-min conversation in each of 5 different realistic acoustic environments. Results Talkers modified their speech, in terms of level and spectrum, in a gradient manner reflecting both the acoustic environment and the degree of hearing impairment of their conversation partner. All pairs of participants were able to maintain communication across all acoustic environments regardless of degree of hearing impairment and the level of environmental noise. Contrasting effects of noise and hearing impairment on speech production revealed distinct patterns of speech modifications produced by normal hearing and hearing-impaired talkers during conversation. This may reflect the fact that only the speech modifications produced by normal hearing talkers functioned to compensate for the hearing impairment of a conversation partner. Conclusions The data presented support the concept of communication effort as a dynamic feedback system between conversation participants. Additionally, these results provide insight into the nature of realistic speech signals, which are encountered by people with hearing impairment in everyday communication scenarios.

Which Plosive Consonant Is More Useful for the Aerodynamic Analysis of Pathologic Voice?

Objectives.

Both acoustic and aerodynamic analyses are essential to evaluate the phonetic characteristics of voice pathology. The purpose of the study is to determine the magnitude of their correlation with the different types of bilabial plosive consonants.

Methods.

A controlled prospective study of 35 patients diagnosed with unilateral vocal fold paralysis was performed. The sustained vowel /a/ and bilabial voiceless consonants were used. Three common acoustic parameters were measured from a sustained vowel /a/ and aerodynamic parameters from a set of syllables /pi/, /p^hi/, and /p’i/. We determined the correlation coefficients between acoustic and aerodynamic measurements for the bilabial plosive consonants /pi/, /p^hi/, and /p’i/.

Results.

The mean values of acoustic parameters were higher than the thresholds of pathology. The mean values of aerodynamic parameters varied according to the types of consonants. The correlation between acoustic and aerodynamic parameters was significantly larger with the consonant /p^hi/ compared with the consonants /p’/ and /p/. The magnitudes of correlation were higher with the consonant /p^hi/ compared with the consonants /p’/ and /p/.

Conclusion.

The plosive consonant /p^hi/ may represent a more valuable investigative consonant than the consonants /p/ or /p’/ for aerodynamic analysis of voice pathology, especially in patients with unilateral vocal fold paralysis.

Impact of Nonmodal Phonation on Estimates of Subglottal Pressure From Neck-Surface Acceleration in Healthy Speakers

Purpose The purpose of this study was to evaluate the effects of nonmodal phonation on estimates of subglottal pressure (Ps) derived from the magnitude of a neck-surface accelerometer (ACC) signal and to confirm previous findings regarding the impact of vowel contexts and pitch levels in a larger cohort of participants. Method Twenty-six vocally healthy participants (18 women, 8 men) were asked to produce a series of p-vowel syllables with descending loudness in 3 vowel contexts (/a/, /i/, and /u/), 3 pitch levels (comfortable, high, and low), and 4 elicited phonatory conditions (modal, breathy, strained, and rough). Estimates of Ps for each vowel segment were obtained by averaging the intraoral air pressure plateau before and after each segment. The root-mean-square magnitude of the neck-surface ACC signal was computed for each vowel segment. Three linear mixed-effects models were used to statistically assess the effects of vowel, pitch, and phonatory condition on the linear relationship (slope and intercept) between Ps and ACC signal magnitude. Results Results demonstrated statistically significant linear relationships between ACC signal magnitude and Ps within participants but with increased intercepts for the nonmodal phonatory conditions; slopes were affected to a lesser extent. Vowel and pitch contexts did not significantly affect the linear relationship between ACC signal magnitude and Ps. Conclusion The classic linear relationship between ACC signal magnitude and Ps is significantly affected when nonmodal phonation is produced by a speaker. Future work is warranted to further characterize nonmodal phonatory characteristics to improve the ACC-based prediction of Ps during naturalistic speech production.

The effect of vocal effort on contrastive voice quality in Shaoxing Wu

Voice quality varies at different levels of communication functions. In order to better understand the range of voice quality variation in normal speech, it is important to examine the interaction between global functions and local functions. This study investigates the effect of vocal effort on the contrastive voice quality in Shaoxing Wu. Results show that register contrasts are maintained in all vocal effort conditions, suggesting that the controls for global vs local functions are rather independent. However, the contrastivity of the registers is modulated by the vocal effort conditions, and the register contrasts are less well-defined in the loud and soft conditions.

Impact of Subharmonic and Aperiodic Laryngeal Dynamics on the Phonatory Process Analyzed in Ex Vivo Rabbit Models

Normal voice is characterized by periodic oscillations of the vocal folds. On the other hand, disordered voice dynamics (e.g., subharmonic and aperiodic oscillations) are often associated with voice pathologies and dysphonia. Unfortunately, not all investigations may be conducted on human subjects; hence animal laryngeal studies have been performed for many years to better understand human phonation. The rabbit larynx has been shown to be a potential model of the human larynx. Despite this fact, only a few studies regarding the phonatory parameters of rabbit larynges have been performed. Further, to the best of our knowledge, no ex vivo study has systematically investigated phonatory parameters from high-speed, audio and subglottal pressure data with irregular oscillations. To remedy this, the present study analyzes experiments with sustained phonation in 11 ex vivo rabbit larynges for 51 conditions of disordered vocal fold dynamics. (1) The results of this study support previous findings on non-disordered data, that the stronger the glottal closure insufficiency is during phonation, the worse the phonatory characteristics are; (2) aperiodic oscillations showed worse phonatory results than subharmonic oscillations; (3) in the presence of both types of irregular vibrations, the voice quality (i.e., cepstral peak prominence) of the audio and subglottal signal greatly deteriorated compared to normal/periodic vibrations. In summary, our results suggest that the presence of both types of irregular vibration have a major impact on voice quality and should be considered along with glottal closure measures in medical diagnosis and treatment.

The Relationship Between Physiological Mechanisms and the Self-Perception of Vocal Effort

Purpose This study aimed to examine the relationship between a large set of hypothesized physiological measures of vocal effort and self-ratings of vocal effort. Method Twenty-six healthy adults modulated speech rate and vocal effort during repetitions of the utterance /ifi/, followed by self-perceptual ratings of vocal effort on a visual analog scale. Physiological measures included (a) intrinsic laryngeal tension via kinematic stiffness ratios determined from high-speed laryngoscopy, (b) extrinsic suprahyoid and infrahyoid laryngeal tension via normalized percent activations and durations derived from surface electromyography, (c) supraglottal compression via expert visual-perceptual ratings, and (d) subglottal pressure via magnitude of neck surface vibrations from an accelerometer signal. Results Individual statistical models revealed that all of the physiological predictors, except for kinematic stiffness ratios, were significantly predictive of self-ratings of vocal effort. However, a combined regression model analysis yielded only 3 significant predictors: subglottal pressure, mediolateral supraglottal compression, and the normalized percent activation of the suprahyoid muscles (adjusted R ² = .60). Conclusions Vocal effort manifests as increases in specific laryngeal physiological measures. Further work is needed to examine these measures in combination with other contributing factors, as well as in speakers with dysphonia.

Descriptive Analysis of the Interactive Patterning of the Vocalization Subsystems in Healthy Participants: A Dynamic Systems Perspective

Purpose Normative data for many objective voice measures are routinely used in clinical voice assessment; however, normative data reflect vocal output, but not vocalization process. The underlying physiologic processes of healthy phonation have been shown to be nonlinear and thus are likely different across individuals. Dynamic systems theory postulates that performance behaviors emerge from the nonlinear interplay of multiple physiologic components and that certain patterns are preferred and loosely governed by the interactions of physiology, task, and environment. The purpose of this study was to descriptively characterize the interactive nature of the vocalization subsystem triad in subjects with healthy voices and to determine if differing subgroups could be delineated to better understand how healthy voicing is physiologically generated. Method Respiratory kinematic, aerodynamic, and acoustic formant data were obtained from 29 individuals with healthy voices (21 female and eight male). Multivariate analyses were used to descriptively characterize the interactions among the subsystems that contributed to healthy voicing. Results Group data revealed representative measures of the 3 subsystems to be generally within the boundaries of established normative data. Despite this, 3 distinct clusters were delineated that represented 3 subgroups of individuals with differing subsystem patterning. Seven of the 9 measured variables in this study were found to be significantly different across at least 1 of the 3 subgroups indicating differing physiologic processes across individuals. Conclusion Vocal output in healthy individuals appears to be generated by distinct and preferred physiologic processes that were represented by 3 subgroups indicating that the process of vocalization is different among individuals, but not entirely idiosyncratic. Possibilities for these differences are explored using the framework of dynamic systems theory and the dynamics of emergent behaviors. A revised physiologic model of phonation that accounts for differences within and among the vocalization subsystems is described. Supplemental Material https://doi.org/10.23641/asha.7616462.

The relationship between acoustical and perceptual measures of vocal effort

Excessive vocal effort is a common clinical voice symptom, yet the acoustical manifestation of vocal effort and how that is perceived by speakers and listeners has not been fully elucidated. Here, 26 vocally healthy adults increased vocal effort during the production of the utterance /ifi/, followed by self-ratings of effort on a 100 mm visual analog scale. Twenty inexperienced listeners assessed the speakers' vocal effort using the visual sort-and-rate method. Previously proposed acoustical correlates of vocal effort were calculated, including: mean sound pressure level (SPL), mean fundamental frequency (f o), relative fundamental frequency (RFF) offset cycle 10 and onset cycle 1, harmonics-to-noise ratio (HNR), cepstral peak prominence and its standard deviation (SD), and low-to-high (L/H) spectral ratio and its SD. Two separate mixed-effects regression models yielded mean SPL, L/H ratio, and HNR as significant predictors of both speaker and listener ratings of vocal effort. RFF offset cycle 10 and mean f o were significant predictors of listener ratings only. Therefore, speakers and listeners attended to similar acoustical cues when making judgments of vocal effort, but listeners also used additional time-based information. Further work is needed to determine how vocal effort manifests in the speech signal in speakers with voice disorders.

Effect of Bhramari Pranayama on the Acoustic and Aerodynamic Parameters of Voice in Normophonic Females

Summary. Objective

Pranayama is known for improving various health conditions. The present study is aimed at investigating the effects of bhramari pranayama on aerodynamic and acoustic parameters of voice in healthy individuals.

Study Design

This is a pretest-posttest design study.

Methods

A total of 24 participants in the age range of 20 to 25 years completed the bhramari pranayama regimen for 30 sessions. Aerodynamic and acoustic assessments were done before and after pranayama sessions. Maximum phonation duration, pitch, loudness, subglottal pressure, glottal airflow, laryngeal resistance and conductance along with acoustical parameters such as average F0, jitter, and shimmer, soft phonation index, noise to harmonic ratio, cepstral peak prominence, and smoothened cepstral peak prominence were analysed.

Results

The results revealed significant improvement in the maximum phonation duration, glottal airflow and pressure, average fundamental frequency, and cepstral peak prominence after practice suggesting that it has an effect on voice parameters.

Conclusion

Bhramari pranayama is effective in improving the acoustic and aerodynamic parameters of voice. The same needs to be investigated in hyper- and hypofunctional voice disorders in the future studies.

Review of differential diagnosis and management of spasmodic dysphonia

PURPOSE OF REVIEW

The recent literature on spasmodic dysphonia is reviewed with regard to pathogenesis, differential diagnosis, treatment options, audits, and current methods of management.

RECENT FINDINGS

Advances in technology have enabled clinicians to better understand the connection between brain and laryngeal function and dysfunction. Refinements in imaging and genetic investigation techniques have led to advances in the understanding of the underlying mechanism of this neurolaryngeal disorder. Development of diagnostic assessment tools and measures of quality of life hold the potential to improve treatment and care.

SUMMARY

Fifty articles published between 2014 and 2015 were selected for this review. The sources were drawn from several clinical specialties: 54% come under the scope of laryngology, 32% from neurology, and 14% from other areas. It remains poorly understood, misdiagnosed, and underdiagnosed. Its identification, diagnosis, treatment selection, and coordination of care require an expert specialist multidisciplinary team. More training is required to help people who have this chronic and psychosocially disabling voice disorder, which impinges on all aspects of their lives. Spasmodic dysphonia is now classified as a 'rare' disease in the United States. This designation will assist in international standards of diagnosis, assessment, treatment, and management.

Magnitude of Neck-Surface Vibration as an Estimate of Subglottal Pressure During Modulations of Vocal Effort and Intensity in Healthy Speakers

PURPOSE

This study examined the relationship between the magnitude of neck-surface vibration (NSVMag; transduced with an accelerometer) and intraoral estimates of subglottal pressure (P'sg) during variations in vocal effort at 3 intensity levels.

METHOD

Twelve vocally healthy adults produced strings of /pɑ/ syllables in 3 vocal intensity conditions, while increasing vocal effort during each condition. Measures were made of P'sg (estimated during stop-consonant closure), NSVMag (measured during the following vowel), sound pressure level, and respiratory kinematics. Mixed linear regression was used to analyze the relationship between NSVMag and P'sg with respect to total lung volume excursion, levels of lung volume initiation and termination, airflow, laryngeal resistance, and vocal efficiency across intensity conditions.

RESULTS

NSVMag was significantly related to P'sg (p < .001), and there was a significant, although small, interaction between NSVMag and intensity condition. Total lung excursion was the only additional variable contributing to predicting the NSVMag-P'sg relationship.

CONCLUSIONS

NSVMag closely reflects P'sg during variations of vocal effort; however, the relationship changes across different intensities in some individuals. Future research should explore additional NSV-based measures (e.g., glottal airflow features) to improve estimation accuracy during voice production.

Influence of glottal closure on the phonatory process in ex vivo porcine larynges

Many cases of disturbed voice signals can be attributed to incomplete glottal closure, vocal fold oscillation asymmetries, and aperiodicity. Often these phenomena occur simultaneously and interact with each other, making a systematic, isolated investigation challenging. Therefore, ex vivo porcine experiments were performed which enable direct control of glottal configurations. Different pre-phonatory glottal gap sizes, adduction levels, and flow rates were adjusted. The resulting glottal closure types were identified in a post-processing step. Finally, the acoustic quality, aerodynamic parameters, and the characteristics of vocal fold oscillation were analyzed in reference to the glottal closure types. Results show that complete glottal closure stabilizes the phonation process indicated through a reduced left-right phase asymmetry, increased amplitude and time periodicity, and an increase in the acoustic quality. Although asymmetry and periodicity parameter variation covers only a small range of absolute values, these small variations have a remarkable influence on the acoustic quality. Due to the fact that these parameters cannot be influenced directly, the authors suggest that the (surgical) reduction of the glottal gap seems to be a promising method to stabilize the phonatory process, which has to be confirmed in future studies.

Estimating Vocal Effort from the Aerodynamics of Labial Fricatives: A Feasibility Study

OBJECTIVE AND HYPOTHESIS

Vocal effort in loud voice is produced with increased subglottal pressure during vowels and increased supraglottal pressure during consonants. In the paper, our main objective is to check whether it was supported by a parallel increase in the airflow resistance of the laryngeal articulator and of the supralaryngeal articulator, here the lips.

STUDY DESIGN AND METHOD

For this comparison, our choice fell on the fricative consonants, as their production allows perfectly synchronous air pressure and airflow measurements. Also, the calculation of the real instantaneous aerodynamic resistance is possible with fricatives-as it is with vowels-whereas it is not possible with plosives. The present feasibility study on a healthy subject is based on direct subglottal and intraoral pressures and airflow measured for /f/ or /v/ and from the contiguous vowel produced in VCVCV nonsense words at different levels of intensity.

RESULTS AND CONCLUSION

The results support that the airflow resistances at the lips and that at the larynx are quite parallel. The airflow resistance at the lips during labial fricative production could provide a good picture of the laryngeal resistance during the production of continuous speech. This suggests clinical applications using both noninvasive inferred measurements of subglottal pressure variation and direct noninferred airflow measurements from more natural speech production tasks.

Estimating Subglottal Pressure From Neck-Surface Acceleration During Normal Voice Production

Purpose

The purpose of this study was to evaluate the potential for estimating subglottal air pressure using a neck-surface accelerometer and to compare the accuracy of predicting subglottal air pressure relative to predicting acoustic sound pressure level (SPL).

Method

Indirect estimates of subglottal pressure (Psg') were obtained from 10 vocally healthy speakers during loud-to-soft repetitions of 3 different /p/-vowel gestures (/pa/, /pi/, /pu/) at 3 pitch levels in the modal register. Intraoral air pressure, neck-surface acceleration, and radiated acoustic pressure were recorded, and the root-mean-square amplitude of the acceleration signal was correlated with Psg' and SPL.

Results

The coefficient of determination between accelerometer level and Psg' was high when data were pooled from all vowel and pitch contexts for each participant (r2 = .68-.93). These relationships were stronger than corresponding relationships between accelerometer level and SPL (r2 = .46-.81). The average 95% prediction interval for estimating Psg' using accelerometer level was ±2.53 cm H2O, ranging from ±1.70 to ±3.74 cm H2O across participants.

Conclusions

Accelerometer signal amplitude correlated more strongly with Psg' than with SPL. Future work is warranted to investigate the robustness of the relationship in nonmodal voice qualities, individuals with voice disorders, and accelerometer-based ambulatory monitoring of subglottal pressure.

The Relationship Between Relative Fundamental Frequency and a Kinematic Estimate of Laryngeal Stiffness in Healthy Adults

PURPOSE

This study examined the relationship between the acoustic measure relative fundamental frequency (RFF) and a kinematic estimate of laryngeal stiffness.

METHOD

Twelve healthy adults (mean age = 22.7 years, SD = 4.4; 10 women, 2 men) produced repetitions of /ifi/ while varying their vocal effort during simultaneous acoustic and video nasendoscopic recordings. RFF was determined from the last 10 voicing cycles before the voiceless obstruent (RFF offset) and the first 10 cycles of revoicing (RFF onset). A kinematic stiffness ratio was calculated for the vocal fold adductory gesture during revoicing by normalizing the maximum angular velocity by the maximum glottic angle during the voiceless obstruent.

RESULTS

A linear mixed effect model indicated that RFF offset and onset were significant predictors of the kinematic stiffness ratios. The model accounted for 52% of the variance in the kinematic data. Individual relationships between RFF and kinematic stiffness ratios varied across participants, with at least moderate negative correlations in 83% of participants for RFF offset but only 40% of participants for RFF onset.

CONCLUSIONS

RFF significantly predicted kinematic estimates of laryngeal stiffness in healthy speakers and has the potential to be a useful clinical indicator of laryngeal tension. Further research is needed in individuals with voice disorders.

The Effect of Head Position and/or Stance on the Self-perception of Phonatory Effort

BACKGROUND

Vocal fatigue is a common but poorly defined complaint of patients presenting with voice disorders. Definitions of vocal fatigue generally include increased self-perceived phonatory effort resulting from references to vocal loading or prolonged voice use resulting in deterioration of function. The present study looks at the role of posture, specifically head position and stance, in self-perceived phonatory effort.

METHODS

Forty-six healthy adults, 13 males and 33 females (mean age was 27.5), with no history of vocal problems/disorders within the past year were recruited. Subjects were asked to sustain the vowel /a/ at a comfortable pitch and loudness for 5-10 seconds in each of six positions: sitting and standing in the manner habitual for each subject, two exaggerated positions of the head (head back and head forward), and two exaggerated positions in standing (standing with knees locked and with knees soft). Each position was repeated three times in randomized order, resulting in 18 trials for each subject. After each repetition of the sustained /a/, subjects were asked to rate their experience of vocal effort using a 100-mm visual analog scale (0-40 least effort, 40-60 habitual effort, and 60-100 increased effort).

RESULTS

Repeated measures analysis of variance revealed significant difference in the self-perceived phonatory effort levels across positions (P value < 0.001). The exaggerated forward and back head positions in both sitting and standing positions showed the greatest significance on the Tukey post hoc tests (P < 0.000).

CONCLUSIONS

Based on the findings, posture may play a more important role in vocal fatigue than previously thought.

The effect of speaking context on spectral- and cepstral-based acoustic features of normal voice

The effect of speaking context on four cepstral- and spectral-based acoustic measures was investigated in 20 participants with normal voice. Speakers produced three different continuous speaking tasks that varied in duration and phonemic content. Cepstral and spectral measures that can be validly derived from continuous speech were computed across the three speaking contexts. Cepstral peak prominence (CPP), low/high spectral ratio, and the standard deviation (SD) of the low/high spectral ratio did not significantly differ across speaking contexts, and correlations for the first two measures were strong among the three speaking tasks. The SD of the CPP showed significant task differences, and relationships between the speaking contexts were generally moderate. These findings suggest that in speakers with normal voice, the differing phonemic content across several frequently used speaking stimuli minimally impacted group means for three clinically relevant cepstral- and spectral-based acoustic measures.

Acoustic Correlates of Compensatory Adjustments to the Glottic and Supraglottic Structures in Patients with Unilateral Vocal Fold Paralysis

The goal of this study was to analyse perceptually and acoustically the voices of patients with Unilateral Vocal Fold Paralysis (UVFP) and compare them to the voices of normal subjects. These voices were analysed perceptually with the GRBAS scale and acoustically using the following parameters: mean fundamental frequency (F0), standard-deviation of F0, jitter (ppq5), shimmer (apq11), mean harmonics-to-noise ratio (HNR), mean first (F1) and second (F2) formants frequency, and standard-deviation of F1 and F2 frequencies. Statistically significant differences were found in all of the perceptual parameters. Also the jitter, shimmer, HNR, standard-deviation of F0, and standard-deviation of the frequency of F2 were statistically different between groups, for both genders. In the male data differences were also found in F1 and F2 frequencies values and in the standard-deviation of the frequency of F1. This study allowed the documentation of the alterations resulting from UVFP and addressed the exploration of parameters with limited information for this pathology.

Individual Monitoring of Vocal Effort With Relative Fundamental Frequency: Relationships With Aerodynamics and Listener Perception

PURPOSE

The acoustic measure relative fundamental frequency (RFF) was investigated as a potential objective measure to track variations in vocal effort within and across individuals.

METHOD

Twelve speakers with healthy voices created purposeful modulations in their vocal effort during speech tasks. RFF and an aerodynamic measure of vocal effort, the ratio of sound pressure level to subglottal pressure level, were estimated from the aerodynamic and acoustic signals. Twelve listeners also judged the speech samples for vocal effort using the visual sort and rate method.

RESULTS

Relationships between RFF and both the aerodynamic and perceptual measures of vocal effort were weak across speakers (R2 = .06-.26). Within speakers, relationships were variable but much stronger on average (R2 = .45-.56).

CONCLUSIONS

RFF showed stronger relationships between both the aerodynamic and perceptual measures of vocal effort when examined within individuals versus across individuals. Future work is necessary to establish these relationships in individuals with voice disorders across the therapeutic process.