Psychometric Analysis of an Ecological Vocal Effort Scale in Individuals With and Without Vocal Hyperfunction During Activities of Daily Living

Evaluating Anterior and Posterior Oral Tongue Contributions to Pressure Generation: A Comparison Between Regular and Effortful Saliva Swallows

PURPOSE

This study determined the contributions of the anterior and posterior tongue regions in tongue pressure generation during regular saliva swallows (SSs) and effortful swallows (ESs) completed under two different instructions. The association between tongue pressure and perceived effort to swallow was also examined.

METHOD

Forty healthy adults without swallowing disorders participated in this study, divided into two age groups: 20 younger (Mage = 21.95 years, SD = 4.43) and 20 older (Mage = 70.10 years, SD = 4.30). Simultaneous data acquisition involved submental surface electromyography, tongue manometry, and a visual analog scale across swallowing conditions (SS, ES with tongue emphasis, and ES with pharyngeal squeezing). The main outcome measures were tongue pressure during swallowing and perceived effort to swallow.

RESULTS

Overall tongue pressure during ESs with tongue emphasis and with pharyngeal squeezing was greater than that during SSs (R2 = .78, p < .001). Moreover, tongue pressure during the ES with tongue emphasis was greater than that during the ES with pharyngeal squeezing (t = 25.63, p < .001). The posterior tongue region generated more pressure during SSs (R2 = .64, p < .001) and the ES with tongue emphasis (R2 = .55, p < .001) than the anterior tongue. Finally, a positive correlation was found between perceived effort and tongue pressure during swallowing (r = .75, 95% CI [0.72, 0.77]).

CONCLUSIONS

Tongue pressure generation was affected by the type of instruction used to elicit ESs, and the posterior tongue showed relatively greater pressure contributions than the anterior tongue for ESs with tongue emphasis and SSs. Furthermore, age-related declines in pressure generation during swallowing were not evidenced in this study, underscoring the ability of healthy older individuals to appropriately modulate lingual pressure during ESs. Last, our results showed that the visual analog scale is a simple tool for rating swallowing effort during ESs, supporting its potential clinical use to train ESs.

Relationships Between Vocal Fold Adduction Patterns, Vocal Acoustic Quality, and Vocal Effort in Individuals With and Without Hyperfunctional Voice Disorders

OBJECTIVES/HYPOTHESIS

Increased vocal effort and aberrant vocal quality are often attributed to vocal fold hyperadduction in hyperfunctional voice disorders. However, there are currently no established methods to quantify vocal fold adduction beyond subjective descriptors in this clinical population. Furthermore, relationships between vocal fold adduction patterns, vocal effort severity, and vocal quality are not well characterized. Therefore, the objectives of this study were to (1) quantify vocal fold adduction, applying a previously validated method developed for patients with vocal fold paralysis, and (2) correlate these measures with acoustic vocal quality and self-perceived measures of vocal effort severity.

METHODS

A deep learning program, Automated Glottic Action Tracking using artificial Intelligence, was used to track glottic angle configurations and vocal fold adduction velocities on laryngoscopic videos across 60 laryngoscopies (20 primary muscle tension dysphonia [pMTD], 20 phonotraumatic lesions, and 20 healthy controls). Voice samples were also acquired, and cepstral peak prominence (CPP) and H1-H2 acoustic measures were used to quantify vocal quality. Participants were also asked to rate their vocal effort on a 100 mm visual analog scale.

RESULTS

There were no significant group differences in glottic angle configurations or vocal fold adduction velocities, although there were trends toward increased peak vocal fold adduction velocities in patients with hyperfunctional voice disorders compared to controls. Vocal effort was significantly higher in the two hyperfunctional groups compared to controls. CPP was significantly lower in the pMTD group, but there were no group differences in acoustic parameters between any of the other groups or for H1-H2 values.

CONCLUSION

Despite significantly more vocal effort reported in patients with hyperfunctional voice disorders, there were no significant group differences in vocal fold adduction patterns. These findings suggest other physiologic mechanisms may also be responsible for the symptoms and genesis of pMTD and benign vocal fold lesions.

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.

Improving Perceptual Speech Ratings: The Effects of Auditory Training on Judgments of Dysarthric Speech

PURPOSE

Auditory training has been shown to reduce rater variability in perceptual voice assessment. Because rater variability is also a central issue in the auditory-perceptual assessment of dysarthria, this study sought to determine if training produces a meaningful change in rater reliability, criterion validity, and scaling magnitude of four features: overall speech impairment, articulatory imprecision, monotony, and slow rate.

METHOD

Forty-four nonexperts randomized to training and nontraining listener groups completed a pretest and posttest. Only the former group underwent auditory training between pre- and posttests. For both testing and training, listeners rated samples from speakers with amyotrophic lateral sclerosis (ALS), speakers with Parkinson's disease (PD), and neurologically healthy control speakers using separate visual analog scales (VASs) for each of the four features. Intraclass correlation coefficients were used to compare inter- and intrarater reliability between pre- and posttest for both listener groups. For criterion validity, severity ratings from the two nonexpert listener groups were compared to those of two experienced listeners for all four features. To determine changes in scaling magnitude, raw VAS scores for each feature were compared from pre- to posttest within the two nonexpert listener groups. Scaling changes were also compared between the two listener groups for the pre- and posttest conditions.

RESULTS AND CONCLUSIONS

In the training group, a meaningful improvement in interrater reliability was observed for some features in all three speaker groups, but not in the nontraining group. In contrast, for intrarater reliability, in the nontraining group, a meaningful improvement was observed for many features in all three speaker groups, but only for PD monotony and slow rate in the training group. All ratings from the nonexpert listeners were valid except for monotony. Raw VAS scores did not meaningfully change from pre- to posttest for any of the features, but there was a trend toward lower scores posttraining, mainly for the ALS samples. Modifications to the auditory training paradigm to further improve reliability and validity, along with future goals for optimizing training, are discussed.

Lexical Characteristics of the Speech Intelligibility Test: Effects on Transcription Intelligibility for Speakers With Multiple Sclerosis and Parkinson's Disease

PURPOSE

Lexical characteristics of speech stimuli can significantly impact intelligibility. However, lexical characteristics of the widely used Speech Intelligibility Test (SIT) are unknown. We aimed to (a) define variation in neighborhood density, word frequency, grammatical word class, and type-token ratio across a large corpus of SIT sentences and tests and (b) determine the relationship of lexical characteristics to speech intelligibility in speakers with multiple sclerosis (MS), Parkinson's disease (PD), and neurologically healthy controls.

METHOD

Using an extant database of 92 speakers (32 controls, 30 speakers with MS, and 30 speakers with PD), percent correct intelligibility scores were obtained for the SIT. Neighborhood density, word frequency, word class, and type-token ratio were calculated and summed for each of the 11 sentences of each SIT test. The distribution of each characteristic across SIT sentences and tests was examined. Linear mixed-effects models were performed to assess the relationship between intelligibility and the lexical characteristics.

RESULTS

There was large variability in the distribution of lexical characteristics across this large corpus of SIT sentences and tests. Modeling revealed a relationship between intelligibility and the lexical characteristics, with word frequency and word class significantly contributing to the model.

CONCLUSIONS

Three primary findings emerged: (a) There was considerable variability in lexical characteristics both within and across the large corpus of SIT tests; (b) there was not a robust association between intelligibility and the lexical characteristics; and (c) findings from a study demonstrating an effect of neighborhood density and word frequency on intelligibility were replicated. Clinical and research implications of the findings are discussed, and three exemplar SIT tests systematically controlling for neighborhood density and word frequency are provided.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Behavioral Treatment Approaches to Lowering Pitch in the Female Voice

PURPOSE

To assess the outcomes of three voice therapy treatment approaches with an emphasis on lowering speaking pitch. Transmasculine and cisgender individuals may desire to lower their speaking pitch, yet there has not been a method described in the literature to do this effectively using only behavioral techniques.

METHOD

To investigate these approaches, we enrolled 32 adult cisgender females and randomly assigned them to one of four treatment groups: vocal function exercises (VFE), resonant voice therapy (RVT), lip-rounding therapy (LRT), and a control group. Participants received individual instruction and feedback on the given exercise program, and they continued to practice daily for 4 weeks.

RESULTS

Acoustic recordings were collected before treatment, immediately after the first session, and after 4 weeks of treatment. Results showed a lower minimum pitch in the physiological range, lower speaking fundamental frequency (SFF) in reading, and lower SFF in spontaneous speech-with treatment groups performing better than the control group. Additionally, participants' self-rating of the vocal effort expended to speak in a low pitch decreased over the treatment period.

CONCLUSIONS

Each treatment approach (VFE, RVT, and LRT) was successful in lowering the speaking pitch of cisgender females. These methods would likely be useful for clients seeking to speak in a lower pitch. Future research may expand results to include clinical populations, such as transmasculine individuals.

Minimally Detectable Change of Speech Intelligibility in Speakers With Multiple Sclerosis and Parkinson's Disease

PURPOSE

This study sought to determine the minimally detectable change (MDC) of sentence intelligibility for speakers with multiple sclerosis (MS) and Parkinson's disease (PD).

METHOD

Speakers included 78 participants consisting of 32 neurologically healthy control speakers, 30 speakers with MS, and 16 speakers with PD. All speakers were recorded reading 11 sentences comprising the Speech Intelligibility Test (SIT), which were subsequently transcribed by inexperienced listeners. Percent correct scores were calculated for each sentence. An average percent correct score was also calculated for each speaker. The MDC at the 95% confidence interval was calculated using the following formula: MDC₉₅ = 1.96 × √2 × standard error of measurement. Speakers were divided into operationally defined categories of severity, and MDCs were calculated for each category to permit comparison to MDCs reported for speakers with amyotrophic lateral sclerosis (ALS). Kruskal-Wallis tests were conducted to compare MDCs between groups and severity categories.

RESULTS

The average MDC₉₅ for control speakers was 5.53% (range = 3.21%-7.47%) and was statistically smaller than MDCs for speakers with MS (average = 10.08%, range = 5.30%-15.62%) and those for speakers with PD (average = 10.98%, range = 8.60%-13.98%). Statistical analyses further revealed significant differences between MDCs across severity categories.

CONCLUSIONS

In agreement with previous work in ALS conducted under similar conditions (i.e., orthographic transcription of SIT sentences in a quiet listening environment), the MDC₉₅ of speech intelligibility ranged from 3% to 10% for speakers with MS and PD who have mildly impaired speech. These estimates are a step toward the development of a universal language with which to evaluate speech changes in a variety of patient populations.