Updating signal typing in voice: addition of type 4 signals

A Comparison of Healthy and Disordered Voices Using Multi-Dimensional Voice Program, Praat, and TF32

PURPOSE

Instrumental voice assessment plays a critical role in identifying vocal issues and for documenting treatment outcomes. The reported voice data, however, are sensitive to the algorithm used by each acoustic analysis software program (AASP) to analyze the corresponding waveform. In the present study, five acoustic measures were compared across healthy speakers and speakers with dysphonia for three AASPs commonly used in research, education, and clinical practice: Multidimensional Voice Program (MDVP) by Computerized Speech Lab, Praat, and TF32.

MATERIALS AND METHODS

Sustained vowel phonations for the quantal vowels /ɑ/, /i/, and /u/ were analyzed for 80 speakers with organic dysphonia and 60 age- and sex-matched healthy controls. Descriptive, inferential, and correlation data are reported for mean fundamental frequency (mean F0), standard deviation of fundamental frequency (SD F0), short-term perturbation measures of jitter and shimmer, and harmonic-to-noise ratio (HNR).

RESULTS

The present study replicated previous findings of interprogram differences for healthy speakers, with MDVP consistently yielding higher values than Praat and TF32 for SD F0, jitter, and shimmer and lower values for HNR. Similar, but magnified patterns of results were observed for speakers with dysphonia.

CONCLUSION

The variation observed across programs calls into question the validity in comparing voice outcomes reported by one AASP to those previously obtained by another, particularly for acoustic signals with aperiodic components that are commonly present in disordered voices. It is advised that waveforms be visually inspected prior to conducting acoustic analysis, and that voice outcomes not be combined or compared across AASPs.

Voice disorder discrimination using vowel acoustic measures in female speakers

BACKGROUND

Sustained vowels are important vocal tasks that have been investigated in discriminating voice disorders using acoustic analysis. To date, no study has combined vowel acoustic measures only that evaluate major aspects of the pathological voice signals in voice disorder discrimination.

AIMS

To investigate the value of vowel acoustic measures that quantify glottal noise, signal stability, signal periodicity, spectral slope and overall voice quality in discriminating female speakers with and without voice disorders.

METHODS & PROCEDURES

Sustained vowel /ɑ/ samples were extracted from 133 voice-disordered female patients and 97 non-voice disordered female speakers and were signal typed prior to analysis. Praat software was used to measure harmonics-to-noise ratio (HNR), glottal-to-noise excitation ratio (GNE), the standard deviation of fundamental frequency (F0SD) and cepstral peak prominence (CPPp); and the Analysis of Dysphonia in Speech and Voice (ADSV) program was used to measure CPPadsv, low/high spectral ratio (LH) and the cepstral/spectral index of dysphonia (CSID). Outcome measures included sensitivity, specificity, and discrimination accuracy.

OUTCOMES & RESULTS

As individual acoustic measures, only spectral-based measures showed good (CPPadsv) and acceptable (CSID) discrimination results. The HNR, GNE and CPPp measures had acceptable sensitivity but poor or non-acceptable specificity and discrimination accuracy. Logistic regression models with all Praat measures (F0SD, HNR, GNE, CPPp) plus ADSV measures (CPPadsv, LH or CSID) provided excellent sensitivity, good-to-excellent specificity and excellent discrimination accuracy. ROC analysis for all individual measures showed that CPPadsv, CSID, CPPp, GNE and F0SD had the highest area under the curve (AUC) values.

CONCLUSIONS & IMPLICATIONS

A combination of acoustic measures that evaluate the major aspects of vocal dysfunction resulted in good to excellent voice discrimination outcomes. Individual acoustic measures had lower discrimination ability than combined measures. The findings implied that acoustic measures extracted from a prolonged vowel were useful in voice disorder discrimination.

WHAT THIS PAPER ADDS

What is already known on this subject Acoustic measures hold great value in discriminating voice disorders from normal voices. However, no study has evaluated discrimination values of a combination of sustained vowel acoustic measures that quantify additive noise, signal stability, signal periodicity, spectral slope and overall voice quality in single-gender cohorts. Previous studies have not used signal typing (the classification of the acoustic signals) for time-based measures, impacting the reliability of discrimination. What this study adds to the existing knowledge This study was the first to implement signal typing to include sustained vowel samples of Types 1 and 2 signals for discrimination statistics. We showed that a combination of vocal acoustic measures using time- and spectral-based extraction from the sustained /ɑ/ vowel evaluating additive noise, signal stability, signal periodicity, spectral slope and overall voice quality resulted in good to excellent sensitivity, specificity and discrimination accuracy. As individual measures, traditional time-based measures such as HNR had rather limited discrimination values whilst spectral-based measures provided higher discrimination values. Measures that are sensitive to signal types have low discrimination ability. What are the potential or actual clinical implications of this work? The sustained vowel /ɑ/ is a relevant, universal vocal task for clinical application using acoustic measures to discriminate female speakers with and without voice disorders if signal typing is implemented. Clinical voice assessment using vowels may not be effective if relying solely on time-based measurements. Spectral-based measures perform better in voice disorder discrimination given their insensitivity to signal types. The most effective voice disorder discrimination could only be obtained using a combination of acoustic measures that quantify major phenomena in the signals of disordered voices. Using measures extracted from both programs, Praat and ADSV, is useful given that specific settings in a program may impact on discrimination accuracy.

Effects of Speech Characteristics on Electroglottographic and Instrumental Acoustic Voice Analysis Metrics in Women With Structural Dysphonia Before and After Treatment

PURPOSE

Literature suggests a dependency of the acoustic metrics, smoothed cepstral peak prominence (CPPS) and harmonics-to-noise ratio (HNR), on human voice loudness and fundamental frequency (F0). Even though this has been explained with different oscillatory patterns of the vocal folds, so far, it has not been specifically investigated. In the present work, the influence of three elicitation levels, calibrated sound pressure level (SPL), F0 and vowel on the electroglottographic (EGG) and time-differentiated EGG (dEGG) metrics hybrid open quotient (OQ), dEGG OQ and peak dEGG, as well as on the acoustic metrics CPPS and HNR, was examined, and their suitability for voice assessment was evaluated.

METHOD

In a retrospective study, 29 women with a mean age of 25 years (± 8.9, range: 18-53) diagnosed with structural vocal fold pathologies were examined before and after voice therapy or phonosurgery. Both acoustic and EGG signals were recorded simultaneously during the phonation of the sustained vowels /ɑ/, /i/, and /u/ at three elicited levels of loudness (soft/comfortable/loud) and unconstrained F0 conditions.

RESULTS

A linear mixed-model analysis showed a significant effect of elicitation effort levels on peak dEGG, HNR, and CPPS (all p < .01). Calibrated SPL significantly influenced HNR and CPPS (both p < .01). Furthermore, F0 had a significant effect on peak dEGG and CPPS (p < .0001). All metrics showed significant changes with regard to vowel (all p < .05). However, the treatment had no effect on the examined metrics, regardless of the treatment type (surgery vs. voice therapy).

CONCLUSIONS

The value of the investigated metrics for voice assessment purposes when sampled without sufficient control of SPL and F0 is limited, in that they are significantly influenced by the phonatory context, be it speech or elicited sustained vowels. Future studies should explore the diagnostic value of new data collation approaches such as voice mapping, which take SPL and F0 effects into account.

Nonlinear Dynamic Analysis and Perturbation Measurement Used for Discriminating Pathological Voices and Their Correlations With Perceptual Evaluation

OBJECTIVE

1. To investigate the discriminatory and diagnostic power of nonlinear dynamic analysis measures concerning voices from normal, benign, and malignant voice disorders. 2. To study the correlations of nonlinear dynamic analysis measures with perceptual ratings to evaluate the reliability of the objective acoustic analysis in predicting severity of voice.

METHOD

The perturbation analysis metrics used were Jitter%, Shimmer%, and signal-to-noise ratio. The nonlinear dynamic analysis metrics used were spectrum convergence ratio (SCR), nonlinear energy difference ratio (NEDR), and rate of divergence (ROD). Subjects were enrolled and divided into three groups based on laryngeal pathology: normal, benign, and malignant. Vowel sound and reading samples were recorded. Perceptual evaluation was applied to these voice samples to investigate correlations between metrics and auditory perception.

RESULT

Each metric was capable of discriminating laryngeal pathology, except for SCR in the case of distinguishing between benign and malignant pathologies. Perturbation analysis parameters had a moderate ability to differentiate between normal and benign pathologies, but were unable to characterize malignant pathologies for certain diseases, such as Reinke's edema. All metrics significantly correlated with perceptual G scores. Nonlinear dynamic analysis was superior when applied to cases of severe dysphonia, where linear metrics such as Jitter% and Shimmer% tended to lose utility. NEDR and ROD were successful at differentiating between the different pathologies, whereas SCR could not discriminate between the benign and malignant groups.

CONCLUSION

Perturbation and nonlinear dynamic analyses are comparable in their discriminating power with respect to normal and benign voices, and normal and malignant voices. The nonlinear dynamic analysis metrics NEDR and ROD may be superior in clinical settings with respect to discriminating voice pathology ranging from mild pathological voice to severe dysphonia, and with respect to discriminating benign and malignant voice. SCR was found unable to discriminate pathological voices.

Comparison Between Custom Smartphone Acoustic Processing Algorithms and Praat in Healthy and Disordered Voices

OBJECTIVE

The aim of this study was to understand the relationship between temporal and spectral-based acoustic measures derived using Praat and custom smartphone algorithms across patients with a wide range of vocal pathologies.

METHODS

Voice samples were collected from 56 adults (11 vocally healthy, 45 dysphonic, aged 18-80 years) performing three speech tasks: (a) sustained vowel, (b) maximum phonation, and (c) the second and third sentences of the Rainbow passage. Data were analyzed to extract mean fundamental frequency (fo), maximum phonation time (MPT), and cepstral peak prominence (CPP) using Praat and our custom smartphone algorithms. Linear regression models were calculated with and without outliers to determine relationships.

RESULTS

Statistically significant relationships were found between the smartphone algorithms and Praat for all three measures (r2 = 0.68-0.95, with outliers; r2 = 0.80-0.98, without outliers). An offset between CPP measures was found where Praat values were consistently lower than those computed by the smartphone app. Outlying data were identified and described, and findings indicated that speakers with high levels of clinician-perceived dysphonia resulted in smartphone algorithm errors.

CONCLUSIONS

These results suggest that the proposed algorithms can provide measurements comparable to clinically derived values. However, clinicians should take caution when analyzing severely dysphonic voices as the current algorithms show reduced accuracy for measures of mean fo and MPT for these voice types.

Differences and Reliability of Linear and Nonlinear Acoustic Measures as a Function of Vocal Intensity in Individuals With Voice Disorders

PURPOSE

Linear acoustic indices are significantly influenced by speaking voice intensity. The main aim of this work was to compare acoustic measures based on linear and nonlinear models in different speaking voice intensity levels and to analyze the reliability of those measures in different intensity levels in subjects with voice disorders.

METHODS

435 samples from subjects (314 women, 121 men with a mean age of 41.07 ± 13.73) diagnosed with various voice disorders were used. In total, 17 acoustic measures were derived from the vowel /ɛ/ sustained at three intensity levels (soft, comfortable, and loud). Five were linear (standard deviation of the fundamental frequency (f0), jitter, shimmer, harmonics-to-noise ratio (HNR) and smoothed cepstral peak prominence (CPPS)), and twelve were nonlinear measures, namely correlation dimension (D2), correlation entropy (H2), first minimum of the mutual information function (FMMI), relative entropy (ENTR-R), largest Lyapunov exponent (Lyap), determinism (DET), transitivity, mean diagonal line length (Lmed), Shannon entropy (ENTR-S), mean length of vertical structures, also known as trapping time (TT), laminarity (LAM) and recurrence period density entropy (RPDE). Differences between speaking voice intensity levels were assessed by Friedman's test and Nemenyi as posthoc test. Intraclass correlation coefficient was used to investigate if each acoustic measure remains in agreement (reliability) between different voice intensity levels.

RESULTS

There were significant differences in all acoustic measures about vocal intensity level (P < 0.001). Intraclass correlation coefficient was very good for HNR (>0.61) and good for Lyap, DET, ENTR-S, Lmed, RPDE, and TT (0.41-0.60).

CONCLUSIONS

All acoustic measures varied as a function of vocal intensity in voice disordered adults, while this relation was different for linear and nonlinear measures. Only the measures HNR, Lyap, DET, ENTR-S, Lmed, RPDE and TT had an acceptable reliability between different voice intensity levels. Therefore, patient`s voice SPL should be controlled or indicated during acoustic vocal assessment.

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.

Longitudinal Vocal Outcomes and Voice-Related Quality of Life After Selective Bilateral Laryngeal Reinnervation: A Case Study

PURPOSE

Bilateral vocal fold paralysis (BVFP) is a severe disorder that can result in respiratory, swallowing, and voice-related problems. Most surgical treatments do not restore laryngeal function and often need to compromise voice quality to preserve respiratory function. Laryngeal reinnervation (LR) may offer a solution to this problem, but literature on longitudinal outcomes of this procedure is scarce. This study aims to report the longitudinal vocal outcomes of BVFP after LR and subsequent voice therapy.

METHOD

The case of a 23-year-old man with BVFP after a traumatic dissection of both recurrent laryngeal nerves is described. Selective bilateral LR of both adductors and abductors was performed 5 months after the onset of BVFP. Voice therapy was provided after the LR procedure. Multidimensional voice assessments, including acoustic, perceptual, and patient-reported outcome measures (PROMs), were conducted 2, 5, 6.5, 8, and 31 months after LR.

RESULTS

An improvement of vocal capabilities and voice quality was noticed 6.5 months after LR, after 4.5 months of voice therapy, with normative values after 2.5 years. PROMs showed an improvement of voice-related quality of life, but some limitations to activities of daily living were still present. Inspiratory arytenoid abduction was not observed on laryngeal videostroboscopic findings in this patient, but tracheostomy was not required.

CONCLUSIONS

Voice therapy after LR helps establish healthy and efficient voice use without increasing compensatory hyperfunctional behavior. More research is needed to examine potential merits of voice therapy in the rehabilitation of vocal and respiratory functions after LR.

Investigation of Vocal Bifurcations and Voice Patterns Induced by Asymmetry of Pathological Vocal Folds

PURPOSE

Vocal fold asymmetry creates irregular entrainments and modulations in voice, which may lead to rough perceptual quality. The presence of asymmetry can also cause mid-phonation bifurcations where a small change in the phonatory system causes a drastic change in vibration pattern, resulting in transitions in and out of rough voice. This study surveys sustained phonation recordings of speakers with the diagnoses of vocal fold polyp or unilateral vocal fold paralysis to investigate the resulting voice patterns.

METHOD

This retrospective study observed 71 sustained phonation recordings from 48 patients. Segments with distinctive signal patterns were identified within each recording with narrowband spectrogram and computer-assisted analysis of spectral peaks.

RESULTS

Phonation segmentation yielded 240 segments across all the recordings. Five voice patterns were recognized: (regularly or irregularly) entrained, modulated, uncoupled, unstable, and pulsed. Thirty-six patients (75%) exhibited irregular patterns. No single irregular pattern lasted for the entire phonation and was always accompanied by at least one mid-phonation bifurcation. Durations of the irregular segments (M = 0.4 s) were significantly shorter than the segments with the regular pattern (M = 1.4 s).

CONCLUSIONS

The results suggest that vocal fold pathology frequently introduces dynamic vibratory patterns that affect both the acoustic signals and perceptions. Due to these abnormalities, it is important for clinical voice assessment protocols, both perceptual and acoustic, to account for these possible bifurcations, irregular signal patterns, and their tendencies.

Impact of Instructed Laryngeal Manipulation on Acoustic Measures of Voice-Preliminary Results

BACKGROUND

Control of laryngeal muscles is required to manipulate pitch, volume, and voice quality. False vocal fold activity (FVFA) refers to the constriction and release of constriction of the false vocal folds. True vocal fold mass (TVFM) represents the cross-sectional thickness of the vocal folds. Larynx height (LH) refers to the vertical position of the larynx in the neck. To date, studies of voice control have examined the effects of these parameters separately. No study has investigated the impact of instructed systematic manipulation of these parameters on acoustic voice measures in vocally healthy trained subjects.

AIMS

This study examined the effects of systematically manipulating FVFA, TVFM, and LH on several acoustic voice measures.

METHOD

Twelve vocally trained speakers were instructed to use specific techniques to achieve experimental conditions of constriction and release of constriction of FVFA, thicker and thinner TVFM, and normal and low LH. Each condition was implemented in combination with manipulating the other parameters. Voice recordings of sustained vowel /a/ and Rainbow Passage were obtained for all laryngeal manipulation conditions and underwent acoustic analyses for fundamental frequency (F0), signal typing, harmonics-to-noise ratio (HNR), cepstral peak prominence (CPP), and vocal relative intensity.

RESULTS

Constricted FVFA caused more aperiodicity in the signals, lower CPP, and lower vocal relative intensity than release of constriction. Thicker TVFM resulted in significantly higher CPP and vocal relative intensity than thinner TVFM. Modifying TVFM did not affect F0 and HNR. Low LH had significantly lower F0 but did not impact on HNR, CPP, and intensity.

CONCLUSIONS

The effects of systematic manipulation of each laryngeal parameter resulted in independent acoustic effects without measurable interaction. Release of constriction of FVFA, thicker TVFM, and low LH were configurations that resulted in more optimal acoustic signals.

[Current methods of acoustic analysis of voice: a review]

Acoustic analysis of the voice, as an objective, quantitative, non-invasive and reproducible method for the evaluation of voice quality, can be used to detect and analyze the acoustic characteristics of normal, artistic or pathological voice. With the development of medicine, physics, statistics, and artificial intelligence technology, there are new advances in the study of voice acoustic analysis, especially in terms of acoustic parameters. In addition, artificial neural networks can be used to perform complex multi-parameter analysis, which greatly improves the efficiency of acoustic analysis. This paper provides an overview of the methods of acoustic analysis and its latest development.

Do the Nonlinear Dynamic Acoustic Measurements, Nonlinear Energy Difference Ratio and Spectrum Convergence Ratio, Correlate with Perceptual Evaluation of Esophageal Voice Speakers?

BACKGROUND

The acoustic assessment of phonation after total laryngectomy is challenged by signal aperiodicity which makes frequency-based acoustic measures less reliable. This is important for patients who use esophageal voice since voice samples mostly include type III (highly aperiodic) and 4 (chaotic) signals. As such, using non-linear measures, which are better suited for aperiodic phonation, may be useful to investigate the relationship between acoustic signal characteristics and perception of esophageal voice quality.

OBJECTIVES

This study aimed to investigate whether nonlinear dynamic acoustic methods, nonlinear energy difference Ratio (NEDR) and spectrum convergence ratio (SCR), were correlated with perceptual measures in subjects who used esophageal phonation.

METHODS

Thirty-one subjects who had undergone total laryngectomy and use esophageal voice as a rehabilitation method were included in this study. Expert and non-expert raters listened to the esophageal voice samples from the subjects and rated vowels and connected speech samples on a scale from 1 to 7 on dysphonia severity and intelligibility. In addition, non-linear acoustic analysis was performed to calculate NEDR and SCR. Analysis from the raters was compared to the non-linear acoustic analysis to find the correlation between the variables.

RESULTS

There were no significant correlations between any of the non-linear acoustic measures NEDR and SCR and the perceptual ratings at the significance level of 0.05. Correlations were calculated for each acoustic measure among the expert raters and among the non-expert raters in both connected speech samples and sustained vowel fragments.

CONCLUSIONS

In conclusion, the nonlinear dynamic acoustic analyses of spectrum convergence ratio and nonlinear energy difference ratio do not have a significant correlation with perceptual measures of esophageal voice.

Voice and communication after open partial horizontal laryngectomies: A cross-sectional outcome study

OBJECTIVE

The present study evaluates voice and communication after open partial horizontal laryngectomies (OPHLs), according to surgery and patient-related variables.

METHODS

Fifty-eight patients were included: 18 type I OPHL, 20 type II OPHL and 20 type III OPHL. Acoustic, aerodynamic, endoscopic, perceptual and self-assessment analyses were carried out. Surgery-related variables and patient-related variables were considered for the analysis.

RESULTS

Type I OPHL revealed the best phonatory outcomes. Type II and type III OPHL showed similar and poor results, with a highly deteriorated voice quality. A significant difference in MTP was found for patients who had both arytenoids/cricoarytenoid units preserved. Age and time from surgery showed significant correlations with voice quality after OPHLs.

CONCLUSIONS

Voice and communication outcomes after OPHLs are heterogeneous and might be influenced by several factors. Knowing variables with a substantial impact on phonatory outcomes may help clinicians in the preoperative decision-making process and the postoperative rehabilitative program.

Phonosurgical Injection Approaches for Voice Restoration After Open Partial Horizontal Laryngectomies: A Pilot Study

OBJECTIVE

The aim of the present study is to evaluate the efficacy of phonosurgical corrective approaches based on injection laryngoplasties and pharyngoplasties followed by speech therapy for voice restoration after unsatisfactory phonatory results of open partial horizontal laryngectomies.

METHODS

Ten patients with not satisfying phonatory results despite speech therapy after type II or type III open partial horizontal laryngectomies (OPHLs) were included. Each patient underwent a voice restoration program based on phonosurgery (injection laryngoplasty and/or injection pharyngoplasty) with hyaluronic acid and/or calcium hydroxyapatite, followed by post-surgical voice rehabilitation. Voices were recorded and analysed through spectrographic, aerodynamic, perceptual, laryngoscopic and self-assessment evaluations before the treatment (T0), after 1 month (T1) and after three months (T2).

RESULTS

Significant improvements in the patients voices were found between T0, T1 and T2 concerning acoustic, perceptual, aerodynamic, laryngoscopic and self assessment evaluations.

CONCLUSIONS

The results of the present study support phonosurgical injection procedures followed by speech therapy as an effective strategy for voice restoration after type II or type III OPHLs in selected patients.

The Relationship Between Pitch Discrimination and Acoustic Voice Measures in a Cohort of Female Speakers

BACKGROUND

Evidence across a range of musically trained, hearing disordered and voice disordered populations present conflicting results regarding the relationship between pitch discrimination (PD) and voice quality. PD characteristics of female speakers with and without a musical training background and no self-reported voice disorder, and the relationship between PD and voice quality in this particular population, have not been investigated.

AIMS

To evaluate PD characteristics in a cohort of female participants without a self-reported voice disorder and the relationship between PD and acoustic voice measures.

METHOD

One hundred fourteen female participants were studied, all of whom self-reported as being non-voice disordered. All completed the Newcastle Assessment of Pitch Discrimination which involved a two-tone PD task. Their voices were recorded producing standardized vocal tasks. Voice samples were acoustically analyzed for frequency-domain measures (fundamental frequency and its standard deviation, and harmonics-to-noise ratio) and spectral-domain measures (cepstral peak prominence and the Cepstral/Spectral Index of Dysphonia). Data were analyzed for the whole cohort and for musical and non-musical training backgrounds.

RESULTS

In the whole cohort, there were no significant correlations between PD and acoustic voice measures. PD accuracy in musically trained speakers was better than in non-trained speakers and correlated with fundamental frequency standard deviation in prolonged vowel tasks. Vocalists demonstrated superior PD accuracy and fundamental frequency standard deviation in prolonged vowels compared to instrumentalists but did not show significant correlations between PD and acoustic measures. The Newcastle Assessment of Pitch Discrimination was a reliable tool, showing moderate-good prediction value in differentiating musical background.

CONCLUSIONS

There was little evidence of a relationship between PD and acoustic measures of voice quality, regardless of musical training background and superior PD accuracy among the musically trained. These data do not support ideas concerning the co-development of perception and action among individuals identified as having voice quality measures within normal ranges. Numerous measures of voice quality, including measures sensitive to pitch, did not distinguish across musically and non-musically trained individuals, despite individual differences in pitch discrimination.

Detecting Bulbar Involvement in Patients with Amyotrophic Lateral Sclerosis Based on Phonatory and Time-Frequency Features

The term "bulbar involvement" is employed in ALS to refer to deterioration of motor neurons within the corticobulbar area of the brainstem, which results in speech and swallowing dysfunctions. One of the primary symptoms is a deterioration of the voice. Early detection is crucial for improving the quality of life and lifespan of ALS patients suffering from bulbar involvement. The main objective, and the principal contribution, of this research, was to design a new methodology, based on the phonatory-subsystem and time-frequency characteristics for detecting bulbar involvement automatically. This study focused on providing a set of 50 phonatory-subsystem and time-frequency features to detect this deficiency in males and females through the utterance of the five Spanish vowels. Multivariant Analysis of Variance was then used to select the statistically significant features, and the most common supervised classifications models were analyzed. A set of statistically significant features was obtained for males and females to capture this dysfunction. To date, the accuracy obtained (98.01% for females and 96.10% for males employing a random forest) outperformed the models in the literature. Adding time-frequency features to more classical phonatory-subsystem features increases the prediction capabilities of the machine-learning models for detecting bulbar involvement. Studying men and women separately gives greater success. The proposed method can be deployed in any kind of recording device (i.e., smartphone).

Telehealth voice assessment by speech language pathologists during a global pandemic using principles of a primary contact model: an observational cohort study protocol

INTRODUCTION

SARS-CoV-2, a highly contagious severe acute respiratory syndrome, has spread to most countries in the world and resulted in a change to practice patterns for the assessment and diagnosis of people with voice disorders. Many services are transitioning to telehealth models to maintain physical distancing measures and conserve personal protective equipment used by healthcare workers during laryngoscopy examinations. The speech-language pathology primary contact (SLPPC) assessment for patients referred to ear, nose and throat (ENT) services in Australia has been shown to reduce waiting times for assessment while streamlining access to ENT assessment and allied health practitioner treatment pathways.

METHODS AND ANALYSIS

A prospective observational cohort study will see patients in a newly developed telehealth model which uses the principles from a usual care SLPPC assessment protocol. Participants will be offered an initial telehealth assessment (speech-language pathology primary contact telehealth (SLPPC-T)) prior to being prioritised for a face-to-face laryngoscopy assessment to complete the diagnostic process. The telehealth assessment will collect sociodemographic information, personal and family medical history, key symptoms, onset and variability of symptoms, red-flag signs or symptoms for laryngeal malignancy, and clinical voice assessment data for auditory-perceptual and acoustic analysis. The study outcomes include (1) association of signs, symptoms and specific voice measures collected during SLPPC-T with voice disorder classification provided after laryngoscopy; (2) degree of concordance between voice disorder classification after SLPPC-T and after laryngoscopy; (3) health service and patient-related costs and health outcomes of the SLPPC-T; (4) patient and stakeholder views and beliefs about the SLPPC-T process.

ETHICS AND DISSEMINATION

Ethical approval has been granted prior to commencement of the study enrolment by the Gold Coast Hospital and Health Service Human Research Ethics Committee (reference number HREC/2020/QGC/62832). Results will be shared through the publication of articles in peer-reviewed medical journals and presentation at national and international scientific meetings.

TRIAL REGISTRATION NUMBER

ACTRN12621000427875.

Probability-Based Best Sample Selection for Acoustic Analysis of Normal and Disordered Voices

PURPOSE

Acoustic analysis is a commonly used method for quantitatively measuring vocal fold function. The accuracy of acoustic analysis depends upon the operator selecting a stable segment of the voice sample to analyze. This paper proposes a novel method to more accurately and reliably select a stable voice segment.

STUDY DESIGN

Four selection methods were implemented to evaluate each raw audio signal and determine the most stable segment of each signal: The proposed modal periodogram method, the moving window method, the midvowel method, and the whole vowel method. Acoustic parameters of interest-namely perturbation (jitter), correlation dimension (D2), and spectrum convergence ratio (SCR)-were calculated for 48 phonation samples to evaluate each method.

METHODS

The proposed modal periodogram method utilizes a minimum mean-square error based approach to calculate a stable modal periodogram and obtain the most stable segment. The Wilcoxon Signed-Rank test was used to compare jitter, D2, and SCR values acquired using the modal periodogram method against the current standard segment selection methods.

RESULTS

The modal periodogram method yielded significantly lower D2 values, and a significantly higher SCR for both normal and disordered voice samples (P < 0.01). This indicates that the modal periodogram method is more apt for selecting a stable audio segment than the other selection methods.

Active Ingredients of Voice Therapy for Muscle Tension Voice Disorders: A Retrospective Data Audit

Background: Although voice therapy is the first line treatment for muscle-tension voice disorders (MTVD), no clinical research has investigated the role of specific active ingredients. This study aimed to evaluate the efficacy of active ingredients in the treatment of MTVD. A retrospective review of a clinical voice database was conducted on 68 MTVD patients who were treated using the optimal phonation task (OPT) and sob voice quality (SVQ), as well as two different processes: task variation and negative practice (NP). Mixed-model analysis was performed on auditory–perceptual and acoustic data from voice recordings at baseline and after each technique. Active ingredients were evaluated using effect sizes. Significant overall treatment effects were observed for the treatment program. Effect sizes ranged from 0.34 (post-NP) to 0.387 (post-SVQ) for overall severity ratings. Effect sizes ranged from 0.237 (post-SVQ) to 0.445 (post-NP) for a smoothed cepstral peak prominence measure. The treatment effects did not depend upon the MTVD type (primary or secondary), treating clinicians, nor the number of sessions and days between sessions. Implementation of individual techniques that promote improved voice quality and processes that support learning resulted in improved habitual voice quality. Both voice techniques and processes can be considered as active ingredients in voice therapy.

Validation and Classification of the 9-Item Voice Handicap Index (VHI-9i)

The international nine-item Voice Handicap Index (VHI-9i) is a clinically established short-scale version of the original VHI, quantifying the patients’ self-assessed vocal handicap. However, the current vocal impairment classification is based on percentiles. The main goals of this study were to establish test–retest reliability and a sound statistical basis for VHI-9i severity levels. Between 2009 and 2021, 17,660 consecutive cases were documented. A total of 416 test–retest pairs and 3661 unique cases with complete multidimensional voice diagnostics were statistically analyzed. Classification candidates were the overall self-assessed vocal impairment (VHIs) on a four-point Likert scale, the dysphonia severity index (DSI), the vocal extent measure (VEM), and the auditory–perceptual evaluation (GRB scale). The test–retest correlation of VHI-9i total scores was very high (r = 0.919, p < 0.01). Reliability was excellent regardless of gender or professional voice use, with negligible dependency on age. The VHIs correlated best with the VHI-9i, whereas statistical calculations proved that DSI, VEM, and GRB are unsuitable classification criteria. Based on ROC analysis, we suggest modifying the former VHI-9i severity categories as follows: 0 (healthy): 0 ≤ 7; 1 (mild): 8 ≤ 16; 2 (moderate): 17 ≤ 26; and 3 (severe): 27 ≤ 36.

Evaluating the Voice Type Component Distributions of Excised Larynx Phonations at Three Subglottal Pressures

Purpose The excised canine larynx provides an advantageous experimental framework in the study of voice physiology. In recent years, signal processing methods have been applied to analyze phonations in excised canine larynx experiments. However, phonations have a highly complex and nonstationary nature corresponding to different proportions of regular and chaotic signal elements. Current nonlinear dynamic methods that are used to assess the degree of irregularity in the voice fail to recognize the distribution of voice type components (VTCs). Method Based on measures of intrinsic dimension, this article presents a method to analyze the VTC distribution of phonations in excised canine larynx experiments. Thirty-nine phonation samples from 13 excised canine larynges at three different subglottal pressures were analyzed. Results Phonation produced with subglottal pressures above phonation instability pressure (PIP) and below phonation threshold pressure (PTP) resulted in high proportions of Voice Types 3 and 4, characterized by chaotic and noisy signals. Phonation produced with pressure between PTP and PIP contained mostly Type 1 voice, characterized by a regular and nearly periodic signal. Mean proportions of all VTCs varied significantly in comparisons of phonations produced with Sub-PTP and PTP as well as in comparisons of phonations produced with PTP and PIP. Conclusions Across all VTCs, the VTC profiles of normal and abnormal phonation differ significantly. Normal phonation is strongly associated with VTC₁ (Voice Type Component 1), whereas abnormal phonation exhibits increased VTC₄ (Voice Type Component 4). The study further demonstrates the ability of intrinsic dimension to successfully detect multiple voice types in an acoustic signal and highlights the need for expanded use of intrinsic dimension in human voice. Supplemental Material https://doi.org/10.23641/asha.14417585.

Do Professionals Who Use the Voice in a Journalistic Context Benefit from Humming as a Semi-occluded Vocal Tract Exercise?

INTRODUCTION

Many vocal enhancement and rehabilitation programs for voice professionals define vocal exercises without analyzing their effects on that specific population in which they will be applied, in the established dose and often without considering the presence and absence of vocal alteration. Journalists have sought the voice clinic due to new professional vocal demands and a vocal program is being elaborated.

OBJECTIVE

To determine the immediate effect of humming in professionals with and without voice disorders who work under high vocal demand in a journalistic context.

METHOD

Thirty-six individuals who completed the Dysphonia Risk Screening Protocol and underwent voice recording participated in the study. Three speech therapists defined the presence and/or absence of vocal changes by consensus. Subsequently, five repetitions of humming were proposed; the exercises lasted five seconds each and were separated by five seconds of complete silence, and recordings were made before and after the exercise (vowel and phrase). For the pre and post comparison between the groups with and without vocal changes, acoustic measurements and spectrogram, including the classification of the signal type, were performed.

RESULTS

The sample had a similar distribution of men and women and a mean age of 39.9 years. Most of the professionals were journalists or reporters. The risk of dysphonia was high for half of the sample, and the presence of vocal changes, predominantly mild ones, was identified in 56%. After the exercise, a decrease in noise at low frequencies and an improvement in the series of harmonics and the signal type were observed in both groups; a decrease in irregularity was observed only in the participants without vocal changes.

CONCLUSION

The proposed humming exercise had an immediate positive effect on the voice of professionals working in a journalistic context, and the changes were particularly evident in aspects of the voice that were initially altered.

Spontaneous Vocal Fold Polyps Remission after Lockdown for Covid-19 Pandemic: Does Vocal Load Matter?

Objective

During the Italian lockdown for Covid-19 emergency, due to stay-at-home orders, many people experienced an unusual period of voice rest. The present case series aims at reporting the spontaneous regression of some vocal fold polyps during the Italian lockdown for SARS-CoV2 pandemic.

Methods

Five patients with voice complaints presenting to a tertiary referral center and diagnosed with vocal fold polyps before the lockdown were included. Because of the lockdown restrictive measures, planned elective surgical procedures were suspended. The patients were re-assessed immediately after lockdown. Multidimensional voice assessments were conducted before and after the lockdown period through laryngostroboscopies, perceptual voice evaluations, electroacoustic analysis and self assessments.

Results

The patients included in the present case series experienced a complete or nearly complete remission of symptoms. Videolaryngostroboscopies documented a complete or nearly complete regression of the polyps. Voices considerably improved both perceptually and electroacoustically. Self assessments showed a reduction of voice-related complaints.

Conclusions

The present study suggests that daily vocal load reduction may play a critical role in the conservative management of vocal fold polyps.

Acoustic voice characteristics with and without wearing a facemask

Facemasks are essential for healthcare workers but characteristics of the voice whilst wearing this personal protective equipment are not well understood. In the present study, we compared acoustic voice measures in recordings of sixteen adults producing standardised vocal tasks with and without wearing either a surgical mask or a KN95 mask. Data were analysed for mean spectral levels at 0-1 kHz and 1-8 kHz regions, an energy ratio between 0-1 and 1-8 kHz (LH1000), harmonics-to-noise ratio (HNR), smoothed cepstral peak prominence (CPPS), and vocal intensity. In connected speech there was significant attenuation of mean spectral level at 1-8 kHz region and there was no significant change in this measure at 0-1 kHz. Mean spectral levels of vowel did not change significantly in mask-wearing conditions. LH1000 for connected speech significantly increased whilst wearing either a surgical mask or KN95 mask but no significant change in this measure was found for vowel. HNR was higher in the mask-wearing conditions than the no-mask condition. CPPS and vocal intensity did not change in mask-wearing conditions. These findings implied an attenuation effects of wearing these types of masks on the voice spectra with surgical mask showing less impact than the KN95.

The Influence of Voice Training on Vocal Learner's Objective Acoustic Voice Components

OBJECTIVE

Acoustic parameters of voice were studied in music majors throughout 18 months of training to understand the influence of voice training on voice.

METHODS

Twenty-three students from Xiamen Music School between 12 and 15 years old were enrolled. Acoustic examination was performed three times- every 6 months for 18 months. Various traditional acoustic parameters were measured, including dysphonia severity index (DSI), jitter, and D-value of vocal range. Nonlinear dynamic measures were also measured, including diffusive chaos to construct voice type component profiles (VTCPs), spectrum convergence ratio, and nonlinear energy difference ratio. The results were analyzed by multivariate analysis of variance.

RESULTS

Over the study duration, there was an improvement of DSI (P = 0.002), and D-value of vocal range (P = 0.000). Among nonlinear parameters, only voice type component data demonstrated significant changes during the study duration. Both Voice Type Component 1(VTC1) and VTC3 values differed from Time 1 to Time 2 as well as from Time 1 to Time 3. The proportion of VTC1 in samples generally decreased, while VTC3, representative of aperiodicity, increased. Both nonlinear energy difference ratio and spectrum convergence ratio exhibited no significant changes throughout the study.

CONCLUSION

Professional voice training can improve DSI and D-value of vocal range in singers' voices. These parameters have potential to be used for voice training evaluation and screening. Many nonlinear parameters did not detect differences in the healthy voices studied, but VTCPs created using intrinsic dimension present a valuable new method, visualizing increases in aperiodicity of the speaking voices after professional voice training.

Using Telepractice to Deliver Pediatric Voice Care in a Changing World: Breaking down Challenges and Learning from Successes

For children with voice disorders, access to care has long been a challenge. Reasons for this include the challenge of qualifying children with isolated voice disorders for services within the public-school system as well as a family's geographic proximity to experienced clinicians who are in the healthcare system. Over the past decade, there have been both formal and informal investigations into the use of telepractice to deliver services to communicatively disordered children and adults, including those with voice disorders. Although barriers and obstacles existed, use of telepractice to deliver such services demonstrated both feasibility and, in some studies, effective outcomes. However, prior to spring of 2020, use of telepractice to deliver speech pathology services was not mainstream. This changed when the nation was forced to shut down many of its in-person healthcare and educational delivery due to the COVID-19 pandemic. This article summarizes select relevant literature pertaining to the use of telepractice in speech language pathology over the past decade and provides a case-based discussion of how it was and is currently being used to deliver pediatric voice care.

Cepstral analysis in patients with a vocal fold motility impairment: advantages of the cepstrum over time-based acoustic analysis

OBJECTIVES

To determine the usefulness of the smoothed cepstral peak prominence (CPPS) in sustained vowel as objective measure of dysphonia.

STUDY DESIGN

This is a retrospective cohort study. 49 patients presenting a vocal cord motility impairment between 2012 and 2018 were included.

METHODS

Classical acoustic parameters, including jitter, shimmer and NHR, as well as the CPPS were obtained for each patient with a vocal cord motility impairment confirmed by means of a fiberoptic laryngoscopy. We calculated the S/E ratio of each patient to establish the glottal efficiency. An independent sample t test and a Pearson correlation test were used to compare data.

RESULTS

Patients presenting a vocal cord motility impairment present abnormal values of the CPPS. Those patients presenting a vocal cord paralysis present lower values of those presenting a vocal cord paresis, with statistically significant difference (P < 0.005). CPPS and the S/E ratio present a moderate negative correlation (- 0.29).

CONCLUSIONS

Subjects with a vocal cord motility impairment present abnormal values for CPPS and those values are lower, the greater the motility impairment is. Therefore, CPPS presents as an objective, measurable and reproducible acoustic parameter of dysphonia that will improve the evaluation of patients presenting vocal pathologies.

Performance of Different Acoustic Measures to Discriminate Individuals With and Without Voice Disorders

The goal of this study is to compare and combine different acoustic features in discriminating subjects with and without voice disorders. A database of 484 adult patients participated in the research. All subjects recorded a sustained vowel /Ɛ/ and underwent a laryngoscopic examination of the larynx. From the results of the laryngeal examination performed by a physician and the auditory-perceptual judgment performed by a Speech-Language Pathologist, the subjects were allocated to the group with (n = 52) and without (n = 432) voice disorder. Four types of acoustic features were used: traditional measures, cepstral measures, nonlinear measures, and recurrence quantification measures. Recordings comprised the emission of the vowel /ε/. Quadratic discriminant analysis was used as classifier. Individual features in the context of traditional, cepstral, and recurrence quantification measures achieved an acceptable performance of ≥70%. Combination of measures improved the classifier performance. The best classification result (86.43% accuracy) was obtained by combining traditional linear and recurrence quantification measures. Results shown that Traditional, Cepstral, and recurrence quantification measures are promising features that capture meaningful information about voice production, which provides good classification performances. The findings of this study can be used to develop a computational tool for voice disorders diagnosis and monitoring.

Substitution Voice Rehabilitation After Open Partial Horizontal Laryngectomy Through the Proprioceptive Elastic Method (PROEL): A Preliminary Study

OBJECTIVE

The aim was to investigate the efficacy of the Proprioceptive Elastic Method (PROEL) in the rehabilitation of the substitution voice after open partial horizontal laryngectomy (OPHL).

STUDY DESIGN

Prospective outcome study.

METHODS

Fifteen patients surgically treated by OPHL type II or type III for laryngeal cancer were recruited (experimental group). Each patient underwent a specific program of voice rehabilitation based on the PROEL method with the same speech and language pathologist. Acoustic-aerodynamic analysis: maximum phonation time (MPT); spectrographic classification (Titze's modified classification), perceptual analysis (INFVo rating scale) and self-assessments (SECEL questionnaire) were performed before the treatment (T0), after 3 months of rehabilitation (T1), and at the end of the 6-month rehabilitation program (T2). A control sample of other 15 patients who underwent OPHL type II or type III and who underwent a standard perioperative rehabilitation was randomly extracted from an historical database and compared to the experimental group.

RESULTS

Significative voice improvements between T0-T1 and T2 were found for acoustic, aerodynamic, perceptual, and self-assessments analysis in the experimental group. Significative differences were found between the experimental group at T2 and the control sample for aerodynamic, self-assessment, and perceptual analysis.

CONCLUSIONS

The results of the present study support PROEL method as an effective approach for substitution voice rehabilitation after OPHL type II and III. Randomized controlled trials on larger groups of patients are needed in future in order to compare PROEL with other rehabilitative approaches.

Voice Signal Typing Using a Pattern Recognition Approach

Voice signal classification in three types according to their degree of periodicity, a task known as signal typing, is a relevant preprocessing step before computing any perturbation measures. However, it is a time consuming and subjective activity. This has given rise to interest in automatic systems that use objective measures to distinguish among the different signal types. The purpose of this paper is twofold. First, to propose a pattern recognition approach for automatic voice signal typing based on a multi-class linear Support Vector Machine, and using rather well-known parameters like Jitter, Shimmer, Harmonic-to-Noise Ratio, and Cepstral Prominence Peak in combination with nonlinear dynamics measures. Two novel features are also proposed as objective parameters. Second, to validate this approach using a large amount of signals coming from two well-known corpora using cross-dataset experiments to assess the generalizability of the system. A total amount of 1262 signals labeled by professional voice pathologists were used with this purpose. Statistically significant differences between all types were found for all features. Accuracies over 82.71% were estimated in all intra-datasets and inter-datasets using cross-validation. Finally, the use of posterior probabilities is proposed as a measure of the reliability of the assigned type. This could help clinicians to make a more informed decision about the type assigned to a voice. These outcomes suggest that the proposed approach can successfully discriminate among the three voice types, paving the way to a fully automatic tool for voice signal typing in the future.

Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Validity

OBJECTIVE

To present evidence of the reliability and validity in the Spectrographic Vocal Assessment Protocol.

METHODS

The sample consisted of 50 female participants, aged 25-62 years old, 24 with a otorhinolaryngological diagnosis of the normal larynx or posterior glottal gap, and 26 diagnosed with vocal fold disturbances. The emission of the vowel /a:/ was analyzed by the Real Time Spectrogram software. The spectrographs were analyzed with a protocol by two speech therapist judges. For reliability analysis, inter- and intrajudge analysis were performed using the Kendall coefficient. For criterion validity, the t test for matched samples with Bonferroni correction was used to compare the average performance of the protocol between the two groups of subjects.

RESULTS

Protocol reliability: for broadband items, the agreement between judges ranged from moderate (0.462) to almost perfect (0.888), and it is significant for all items, and an intrajudge agreement was almost perfect and significant (0.865-1.000) for all items. For narrowband items, the agreement between judges ranged from moderate (0.469) to almost perfect (0.922), and it is significant for all items except for the presence of "subharmonics in high frequencies" where agreement was moderate (0.504), but not significant, and the intrajudge agreement was almost perfect (0.874-1.000) and significant for all items. Criterion validity: for most broadband and narrowband items, the groups with normal or altered diagnosis differed statistically.

CONCLUSION

The Spectrographic Vocal Assessment Protocol presented adequate evidence in reliability and validity.

Development and Evidence of Content Validity of the Spectrographic Vocal Assessment Protocol (SVAP)

OBJECTIVE

To develop and seek evidence of content validity of a spectrographic vocal assessment protocol.

METHODS

Methodological study for development and validation of an assessment instrument. A broad literature search was conducted to develop and substantiate a spectrographic vocal assessment protocol. The protocol items were sent to five expert judges, speech therapists, nonauthors of the research, doctors, and clinicians, with experience in the field of voice and spectrographic acoustic analysis, who individually analyzed the protocol items. For data analysis, the Gwet analysis and the Content Validity Ratio formula were used.

RESULTS

The Spectrographic Vocal Assessment Protocol was developed, subdivided into Broadband and Narrowband. Twenty-four protocol items had Content Validity Ratio 1.0 and 25 items had 0.6. Gwet analysis indicated substantial agreement (0.656) for broadband and almost perfect (0.848) for narrowband items.

CONCLUSION

Evidence of satisfactory content validity was obtained in the development of the protocol.

Classificação espectrográfica do sinal vocal: relação com o diagnóstico laríngeo e a análise perceptivo-auditiva

RESUMO Objetivo Verificar se existe associação entre a presença de alteração laríngea, a análise perceptivo-auditiva da qualidade vocal e a classificação espectrográfica do sinal vocal em indivíduos com distúrbio de voz. Métodos Participaram 478 pacientes com distúrbios de voz. Foi realizada gravação da vogal /Ɛ/ sustentada e o exame médico para estabelecimento de diagnóstico laríngeo. Os espectrogramas da vogal foram utilizados para classificação dos sinais em Tipo I, II, III e IV. Resultados Vozes de indivíduos sem alteração laríngea foram classificadas, predominantemente, como Tipo I e Tipo II, enquanto sinais de indivíduos com alteração laríngea foram classificados nos Tipos III e IV. Vozes desviadas foram classificadas, predominantemente, como Tipo II, enquanto os sinais de pacientes com desvio vocal foram categorizados, predominantemente, como Tipos II e III. Apenas os sinais de indivíduos com desvio vocal foram classificados como Tipo IV. Sinais Tipo III e IV apresentaram valores mais elevados no grau geral do desvio e nos graus de rugosidade e soprosidade, em relação aos sinais Tipo I e Tipo II. Os sinais Tipo IV apresentaram maior grau geral e graus de rugosidade e soprosidade, em comparação aos sinais Tipo III. Apenas os sinais Tipo IV apresentaram valores mais elevados no grau de tensão, em relação aos sinais Tipo I, II e III. Conclusão Há associação entre a presença de alteração laríngea, a análise perceptivo-auditiva e a classificação espectrográfica do sinal vocal em indivíduos com distúrbio de voz.

Auditory Skills as a Predictor of Rater Reliability in the Evaluation of Vocal Quality

OBJECTIVE

To determine whether an association exists between auditory skills and the reliability of judgments of the vocal deviation grade and the degrees of roughness and breathiness and to evaluate whether these skills are predictive of interrater reliability in auditory-perceptual evaluations.

METHODS

The sample consisted of 20 speech-language pathology students without previous training in auditory-perceptual evaluation. The students underwent a basic audiological evaluation and a central auditory processing evaluation. They then participated in two auditory-perceptual evaluation sessions assessing the general grade (GG) and the degrees of roughness and breathiness of 44 samples of sustained vowel production with the presence or absence of dysphonia. For statistical analysis, the intraclass correlation coefficient (ICC) and a beta regression model were used.

RESULTS

A difference was found in the average ICCs of the GG parameter between listeners with high and low temporal resolution and binaural interaction skills. Temporal resolution skills and binaural interaction affected the ICC of listeners in the GG evaluation, reducing the likelihood of reliability by 2.8 and 3.6 times, respectively.

CONCLUSION

An association exists between temporal resolution skills and binaural interaction and the reliability of listeners in evaluations of vocal deviation severity. Listeners with low levels of these skills show less reliability in evaluations of the severity of vocal deviation. In addition, temporal resolution and binaural interaction are predictors and explain 42.7% of the variability in the reliability of evaluations of vocal deviation severity.

A Case of Nervus Laryngeus Superior Paresis Treated With Novafon Local Vibration Voice Therapy

OBJECTIVE

The aim of the study is to present a case of chronic idiopathic superior laryngeal nerve paresis (SLNp) treated with a novel voice therapy approach called Novafon Local Vibration Voice Therapy (NLVVT).

METHODS

Outcome measurements including acoustics, aerodynamics, and self-perception of voice handicap were acquired before intervention (i.e., NLVVT) and after intervention (i.e.,follow-up). The use of NLVVT was modified from previous reports of use in functional voice disorders for application to a neurological voice disorder (SLNp).

RESULTS

The results showed that NLVVT had meaningful improvements in Voice Range Profile boundaries, an increase in speaking fundamental frequency, and improved acoustic indices of voice quality in a case of SLNp. The follow-up after NLVVT intervention revealed maintenance of the post-treatment improvements at a 1-month measurement interval.

CONCLUSION

The NLVVT program may have potential to improve voice quality and vocal function in a case of SLNp. Further research is necessary to test a potential effectiveness for NLVVT applied to vocal fold immobility due to paresis in both larger numbers of patients and more well-designed, controlled experiments.

Injection laryngoplasty as adjunct treatment method for muscle tension dysphonia: Preliminary findings

Objectives

This study examined the effectiveness of injection laryngoplasty (IL) in muscle tension dysphonia (MTD) patients who did not fully respond to voice therapy. It was hypothesized that IL would improve voice quality and voice‐related quality of life measures in MTD.

Methods

A retrospective review was conducted on 37 patients with a primary diagnosis of MTD who underwent IL following a suboptimal response to voice therapy (mean age = 43.0 years; standard deviation [SD] = 13.4; range = 23 to 71). Outcome measures included laryngoscopic signs of supraglottic constriction, Voice Handicap Index‐10 (VHI‐10) scores, maximal phonation time, vowel fundamental frequency (F0), standard deviation of F0 (F0SD), harmonics‐to‐noise ratio (HNR), and smoothed cepstral peak prominence. These were compared between baseline and within 3 months following the IL procedure.

Results

There was significant decrease in supraglottic constriction. Mean (SD) of VHI‐10 scores decreased from 25.4 (5.7) at baseline to 15.3 (9.3) following IL. This improvement in VHI‐10 was observed in patients with and without baseline glottal insufficiency (GI). Mean (SD) of HNR (decibels) increased from 21.1 (5.4) at baseline to 22.8 (4.3) after IL. Only patients with GI demonstrated a significant improvement in HNR from baseline to post‐IL. No statistically significant differences in other acoustic measures were observed.

Conclusions

IL resulted in positive changes in voice‐related quality of life in MTD patients with and without GI. Acoustically, only those with GI demonstrated an increase in HNR following IL. Further studies are needed to examine the effects of IL in MTD.

Level of Evidence

4 Laryngoscope, 130:980–985, 2020

The relationship between biomechanics of pharyngoesophageal segment and tracheoesophageal phonation

This study examined the relationship between biomechanical features of the pharyngoesophageal (PE) segment, acoustic characteristics of tracheoesophageal (TE) phonation, and patients’ satisfaction with TE phonation. Fifteen patients using TE phonation after total laryngectomy completed the Voice Symptom Scale (VoiSS) and underwent acoustic voice analysis for cepstral peak prominence (CPP) and relative intensity. High resolution manometry (HRM) combined with videofluoroscopy was used to evaluate PE segment pressure and calculate the pressure gradient (ΔP), which was the pressure difference between the upper oesophagus and a point two centimetres above the vibrating PE segment. The upper oesophageal sphincter (UOS) minimal diameters were measured by Endolumenal Functional Lumen Imaging Probe (EndoFLIP). HRM detected rapid pressure changes at the level of the 4th – 6th cervical vertebra. CPP, relative intensity, and ΔP were significant predictors of satisfactory TE phonation. ΔP was a significant predictor of CPP and intensity. Minimal UOS diameter was a significant predictor of relative intensity of TE phonation. In two patients with unsuccessful TE phonation, endoscopic dilatation subsequently restored TE phonation. These findings suggest that sufficient ΔP and large UOS diameter are required for satisfactory TE phonation. Endoscopic dilatation increasing UOS diameter may provide a new approach to treat unsuccessful TE phonation.

Quantification of Voice Type Components Present in Human Phonation Using a Modified Diffusive Chaos Technique

Purpose:

Signal typing has been used to categorize healthy and disordered voices; however, human voices are likely comprised of differing proportions of periodic type 1 elements, type 2 elements that are periodic with modulations, aperiodic type 3 elements, and stochastic type 4 elements. A novel diffusive chaos method is presented to detect the distribution of voice types within a signal with the goal of providing an objective and clinically useful tool for evaluating the voice. It was predicted that continuous calculation of the diffusive chaos parameter throughout the voice sample would allow for construction of comprehensive voice type component profiles (VTCP).

Methods:

One hundred thirty-five voice samples of sustained /a/ vowels were randomly selected from the Disordered Voice Database Model 4337. All samples were classified according to the voice type paradigm using spectrogram analysis, yielding 34 type 1, 35 type 2, 42 type 3, and 24 type 4 voice samples. All samples were then analyzed using the diffusive chaos method, and VTCPs were generated to show the distribution of the 4 voice type components (VTC).

Results:

The proportions of VTC1 varied significantly between the majority of the traditional voice types ( P < .001). Three of the 4 VTCs of type 3 voices were significantly different from the VTCs of type 4 voices ( P < .001). These results were compared to calculations of spectrum convergence ratio, which did not vary significantly between voice types 1 and 2 or 2 and 3.

Conclusion:

The diffusive chaos method demonstrates proficiency in generating comprehensive VTCPs for disordered voices with varying severity. In contrast to acoustic parameters that provide a single measure of disorder, VTCPs can be used to detect subtler changes by observing variations in each VTC over time. This method also provides the advantage of quantifying stochastic noise components that are due to breathiness in the voice.

The Impact of Nasalance on Cepstral Peak Prominence and Harmonics-to-Noise Ratio

Objectives/Hypothesis

Cepstral peak prominence (CPP) has been reported as a reliable measure of dysphonia and a preferred alternative to harmonics‐to‐noise ratio (HNR). However, CPP has been observed to be sensitive to articulatory variation and vocal intensity. The aim of this study was to examine the impact of nasalance on CPP and HNR of voice signals. It was hypothesized that increased nasalance would be associated with decreased CPP.

Study Design

Within‐subject correlation design.

Methods

Thirty vocally healthy female participants were recorded reading and producing a vowel in alternation with a nasal consonant while wearing a nasometer for calculation of nasalance. Recorded vowel, nasalized, and nasal segments of speech were used to calculate CPP using Analysis of Dysphonia in Speech and Voice software, and HNR and vocal intensity using Praat software.

Results

Significant main effects of conditions were observed for CPP. CPP values decreased significantly when phonation changed from vowel to nasalized vowel and to nasal. There was correlation between CPP and nasalance and between CPP and intensity. HNR was slightly higher in the nasal condition than in vowel. There was a weak correlation between HNR and nasalance. No correlation was found between HNR and intensity.

Conclusions

CPP is sensitive to changes in vocal tract configuration caused by nasalization as well as intensity, whereas HNR is not. Therefore, CPP may reflect the periodicity in source signal or the filtering effects of vocal tract. Further research is needed to clarify the application and interpretation of CPP in clinical practice.

Level of Evidence

4

Laryngoscope, 129:E299–E304, 2019

Comparing the Nonlinear Dynamic Acoustic Parameters of Healthy Adult and Pediatric Voices

Objectives:

The aims of this study were to compare nondysphonic adult and pediatric voices using linear and nonlinear acoustic parameters and to evaluate the ability of adult spectrum convergence ratio (SCR) and rate of divergence (ROD) reference values to correctly identify a pediatric voice type as periodic or aperiodic.

Methods:

Twenty adult and 36 pediatric nondysphonic voice samples were collected and analyzed using linear and nonlinear acoustic parameters. Absence of voice disorder was confirmed using perceptual acoustic and spectral analysis. Mean values for jitter, shimmer, SCR, and ROD were compared between adults and children, across specific age groups, and within genders. Using adult reference values for SCR and ROD, samples were classified as primarily periodic or aperiodic and typed using spectral analysis. Rates of accurate typing were also compared between subject groups.

Results:

Overall, jitter and shimmer were similar among the adult and pediatric age groups. ROD was significantly different among the 3 pediatric and 1 adult group; the pediatric age groups were similar to one another. Adult SCR was also significantly different from all of the pediatric age groups. In adult men, ROD and SCR were significantly different from all of the pediatric age groups; the pediatric age groups were similar to one another. In female subjects, ROD was significantly different among all age groups. The ROD and SCR reference values were significantly better at categorizing adult voice types compared with pediatric voice types.

Conclusions:

In healthy subjects, SCR and ROD have discriminatory power for identifying adult versus pediatric voices, while jitter and shimmer cannot differentiate between the 2 groups. However, age- and gender-specific pediatric reference values must be determined to accurately classify voice types using SCR and ROD.

Exploiting nonlinearity of the speech production system for voice disorder assessment by recurrence quantification analysis

This work summarizes the research related to digital speech signal processing with recurrence quantification analysis (RQA) applied to voice disorder assessment. The main motivation for these studies is the fact that RQA is able to exploit the nonlinear dynamical nature of the speech production system. Due to the use of recurrence quantification measures to represent the behavior of speech signals, promising results were obtained in the characterization and classification of laryngeal pathologies and voice disorders. These contributions may help one to evaluate the usability and efficiency of RQA in vocal disorder assessment.

Treatment Effectiveness of Novafon Local Vibration Voice Therapy for Dysphonia Treatment

BACKGROUND

The objective of this study was to explore the effectiveness of the five-week Novafon local vibration voice therapy (NLVVT) program with and without Novafon local vibration for dysphonia treatment.

METHODS

Twenty-two voice-disordered subjects were divided into two groups. The intervention group (IG) performed the NLVVT program and the control group (CG) had the same voice exercises of this program without local vibration.

RESULTS

After NLVVT, the IG showed significantly high results in all parameters of acoustics, multiparametric indices, and self-evaluation (all P values < 0.01). The CG revealed mostly much significantly lower results (P values < 0.05) or nonsignificant results for these parameters after the treatment. The intergroup comparison under consideration before and after NLVVT showed a large and significant treatment effect in voice quality (ie, narrowband spectrograms, and Acoustic Voice Quality Index), in which the IG had better treatment results. The aerodynamic measurement showed no significant changes for both groups after NLVVT (P value > 0.05).

CONCLUSION

After the NLVVT program both groups showed significant improvements of various voice measurements, in which the IG revealed better treatment results than the CG. However, next to voice exercises an extra benefit for local vibration with the Novafon appliance was assessed in voice quality.

Performance of the phonatory deviation diagram in the evaluation of rough and breathy synthesized voices

Introduction

Voice disorders alter the sound signal in several ways, combining several types of vocal emission disturbances and noise. The phonatory deviation diagram is a two-dimensional chart that allows the evaluation of the vocal signal based on the combination of periodicity (jitter, shimmer, and correlation coefficient) and noise (Glottal to Noise Excitation) measurements. The use of synthesized signals, where one has a greater control and knowledge of the production conditions, may allow a better understanding of the physiological and acoustic mechanisms underlying the vocal emission and its main perceptual-auditory correlates regarding the intensity of the deviation and types of vocal quality.

Objective

To analyze the performance of the phonatory deviation diagram in the discrimination of the presence and degree of roughness and breathiness in synthesized voices.

Methods

871 synthesized vocal signals were used corresponding to the vowel /ɛ/. The perceptual-auditory analysis of the degree of roughness and breathiness of the synthesized signals was performed using visual analogue scale. Subsequently, the signals were categorized regarding the presence/absence of these parameters based on the visual analogue scale cutoff values. Acoustic analysis was performed by assessing the distribution of vocal signals according to the phonatory deviation diagram area, quadrant, shape, and density. The equality of proportions and the chi-square tests were performed to compare the variables.

Results

Rough and breathy vocal signals were located predominantly outside the normal range and in the lower right quadrant of the phonatory deviation diagram. Voices with higher degrees of roughness and breathiness were located outside the area of normality in the lower right quadrant and had concentrated density.

Conclusion

The normality area and the phonatory deviation diagram quadrant can discriminate healthy voices from rough and breathy ones. Voices with higher degrees of roughness and breathiness are proportionally located outside the area of normality, in the lower right quadrant and with concentrated density.

Application of Local Intrinsic Dimension for Acoustical Analysis of Voice Signal Components

Purpose:

The overall aim of this study was to apply local intrinsic dimension ( Di) estimation to quantify high-dimensional, disordered voice and discriminate between the 4 types of voice signals. It was predicted that continuous Di analysis throughout the entire time-series would generate comprehensive descriptions of voice signal components, called voice type component profiles (VTCP), that effectively distinguish between the 4 voice types.

Method:

One hundred thirty-five voice recording samples of the sustained vowel /a/ were obtained from the Disordered Voice Database Model 4337 and spectrographically classified into the voice type paradigm. The Di and correlation dimension ( D2) were then used to objectively analyze the voice samples and compared based on voice type differentiation efficacy.

Results:

The D2 exhibited limited effectiveness in distinguishing between the 4 voice type signals. For Di analysis, significant differences were primarily observed when comparing voice type component 1 (VTC1) and 4 (VTC4) across the 4 voice type signals ( P < .001). The 4 voice type components (VTCs) significantly differentiated between low-dimensional, type 3 and high-dimensional, type 4 signals ( P < .001).

Conclusions:

The Di demonstrated improvements over D2 in 2 distinct manners: enhanced resolution at high data dimensions and comprehensive description of voice signal elements.

Applied Chaos Level Test for Validation of Signal Conditions Underlying Optimal Performance of Voice Classification Methods

PURPOSE

The purpose of this study is to introduce a chaos level test to evaluate linear and nonlinear voice type classification method performances under varying signal chaos conditions without subjective impression.

STUDY DESIGN

Voice signals were constructed with differing degrees of noise to model signal chaos. Within each noise power, 100 Monte Carlo experiments were applied to analyze the output of jitter, shimmer, correlation dimension, and spectrum convergence ratio. The computational output of the 4 classifiers was then plotted against signal chaos level to investigate the performance of these acoustic analysis methods under varying degrees of signal chaos.

METHOD

A diffusive behavior detection-based chaos level test was used to investigate the performances of different voice classification methods. Voice signals were constructed by varying the signal-to-noise ratio to establish differing signal chaos conditions.

RESULTS

Chaos level increased sigmoidally with increasing noise power. Jitter and shimmer performed optimally when the chaos level was less than or equal to 0.01, whereas correlation dimension was capable of analyzing signals with chaos levels of less than or equal to 0.0179. Spectrum convergence ratio demonstrated proficiency in analyzing voice signals with all chaos levels investigated in this study.

CONCLUSION

The results of this study corroborate the performance relationships observed in previous studies and, therefore, demonstrate the validity of the validation test method. The presented chaos level validation test could be broadly utilized to evaluate acoustic analysis methods and establish the most appropriate methodology for objective voice analysis in clinical practice.