Suitability of Acoustic Perturbation Measures in Analysing Periodic and Nearly Periodic Voice Signals

The Effectiveness of Vocal Hygiene Education With Resonant Voice Therapy for School-Aged Children With Vocal Nodules

OBJECTIVE

This study evaluated the effectiveness of vocal hygiene education with resonant voice therapy for school-aged children with vocal nodules.

STUDY DESIGN

A pre-test/post-test control group design was employed.

METHODS

Seventeen children aged between 6 and 9 years old with vocal nodules were randomly assigned to three groups: a treatment group, a placebo group and a control group. Children in the treatment group (n = 7) received six consecutive, weekly, one-hour sessions of vocal hygiene education with resonant voice therapy. Children in the placebo group (n = 5) received six consecutive, weekly, one-hour sessions on presentation skills training. Children in the control group (n = 5) did not receive any form of treatment. Subjective outcome measures included auditory-perceptual evaluation of overall dysphonia severity, the Pediatric Voice Handicap Index (pVHI) and the Children's Voice Handicap Index-10 (CVHI-10). Objective outcome measures included acoustic analysis of fundamental frequency, jitter, shimmer and noise-to-harmonic ratio.

RESULTS AND CONCLUSIONS

Significant improvements in perceptual ratings of overall dysphonia severity levels and pVHI scores were found in the treatment group. No significant changes in acoustic measures and CVHI-10 scores were noted in any of the three groups. Interestingly, an improvement in perceptual overall dysphonia severity levels at post-evaluation was observed in the no treatment control group.

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.

Voice Therapy Improves Acoustic and Auditory-Perceptual Outcomes in Children

PURPOSE

This study employed acoustic measures as well as auditory-perceptual assessments to examine the effects of voice therapy in children presenting with benign vocal fold lesions.

METHODS

A retrospective, observational cohort design was employed. Sustained vowels produced by 129 children diagnosed with benign vocal fold lesions were analyzed, as well as connected speech samples produced by 47 children. Treatment outcome measures included Consensus of Auditory-Perceptual Evaluation of Voice (CAPE-V), jitter, shimmer, Noise-to-Harmonic Ratio (NHR), cepstral peak prominence (CPP), and Low-to-High Ratio (LHR) on sustained vowels, and CPP and LHR on connected speech.

RESULTS

Following voice therapy, significant improvements in CAPE-V ratings (p < 0.001) were observed. Additionally, jitter (p = 0.041), NHR (p = 0.019), and CPP (p < 0.01) on sustained vowels, and CPP (p = 0.002), and LHR (p = 0.008) on connected speech significantly improved following voice therapy. CPP increased with age in males but did not change in females. CAPE-V ratings and perturbation measures indicated that dysphonia was more severe in younger children pre and post-therapy.

CONCLUSIONS

Auditory-perceptual and acoustic measures demonstrated improved voice quality following voice therapy in children with dysphonia. CPP effectively quantified voice therapy gains and allowed for analysis of connected speech, in addition to sustained vowels. These findings demonstrate the value of CPP as a tool in assessing therapy outcomes and support the efficacy of voice therapy for children presenting with vocal fold lesions.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:977-983, 2023.

Comparison of Vocal Fatigue in Speech Therapists With Other Rehabilitation Therapists

INTRODUCTION

Voice, as one of the most important communication tools in humans, can cause many problems in a person's daily life if it is damaged. One type of voice complaint is vocal fatigue, which is common among people who use their voices a lot. Rehabilitation therapists may be more vulnerable to a variety of vocal disorders and complaints due to extensive voice use and long-term relationships with clients. The aim of this study is to investigate and compare vocal fatigue among therapists in Ahvaz rehabilitation fields.

METHOD

This cross-sectional, descriptive-analytical study was performed on 100 therapists in Ahvaz rehabilitation fields. For this purpose, the Persian version of the vocal fatigue index questionnaire has been used. One Way Anova parametric tests were used to compare target variables. The relationship between vocal fatigue and work experience and working hours per day was calculated using Spearman correlation coefficient.

RESULTS

A comparison of the scores of the vocal fatigue index in the rehabilitation therapists showed that there was a significant difference between the therapists scores in the field of speech therapy and the therapists scores in other fields (P < 0.05).

CONCLUSION

Due to the nature of rehabilitation fields and the use of voice during daily interactions with different clients, especially clients with special disabilities, the possibility of voice disorders and complaints in this population should be considered. Therefore, providing the necessary training for voice care and voice health of this population should be noted in order to prevent voice disorders and complaints.

Voice outcomes and its impact on quality of life after open airway surgery in children

INTRODUCTION

Open airway surgery is used to treat severe grades of laryngotracheal stenosis in children. Scarring of the airway following these procedures may lead to voice impairment and impact quality of life. This study was designed to characterize vocal outcome in children submitted reconstructive airway surgery and verify how this correlates to voice related quality of life in this population.

MATERIAL AND METHODS

Children submitted to open airway surgery that had been decannulated for a minimum of 30 days and had functional speech were invited to participate. Pediatric Voice-Related Quality-of-Life survey (PVRQoL) was applied, consensus auditory perceptive of voice (CAPE-V) protocol was used for perceptual voice evaluation and acoustic analysis was performed using Praat software.

RESULTS

Twenty children were enrolled in the study with an average age of 4 years and 8 months. Averages for PVRQoL exceeded normative values in 80% of the children. Half of the children had normal voice or mild dysphonia and half had moderate dysphonia, according to perceptual evaluation. Measures of F0, jitter and particularly shimmer were abnormal in most of the children.

CONCLUSION

Voice quality varies from normal to moderately impaired in children following reconstructive airway surgery. Voice quality impacts quality of life in the majority of cases and the degree of dysphonia does not always correlate with voice related quality of life scores.

Correlation of the Iranian Voice Quality of Life Profile (IVQLP) with Acoustic Measurements across Three Common Voice Disorders

OBJECTIVES

The Iranian Voice Quality of Life Profile (IVQLP) is a recent culture-based developed tool for assessing the quality of life of dysphonic patients. The research questions addressed here are as follows: (1) Are the correlations between IVQLP scores and values of objective voice measures? (2) Do the correlations differ across the three different voice disorders?

METHODS

The subjects were divided into three groups: muscle tension dysphonia (MTD) (n = 62), benign midmembranous vocal fold lesions (n = 56), and unilateral vocal fold paralysis (UVFP) (n = 32). The study sample consisted of 91 males and 59 females. The individuals had a mean age of 46.53 ± 13.84 years. All of the participants completed the IVQLP questionnaire. The PRAAT software was used to provide acoustic analyses. The correlations between fundamental frequency (F0), perturbation analyses, harmonics-to-noise ratio, and IVQLP data of the three groups of patients were measured using Pearson's correlation.

RESULTS

There was a significant correlation between the total score and jitter in the MTD group. For the benign vocal fold lesion group, correlations were significant and relatively strong for numerous analyses. Again, there were numerous significant and strong correlations for the UVFP group.

CONCLUSIONS

Results may indicate two interpretations. One interpretation of the results is that patients with morphological tissue changes (lesions, paralysis) appear to associate their sense of how their voice problem negatively affects their lives. A second interpretation is that there is perhaps a threshold of vocal perturbation or instability that lends itself to a patient's connection to his or her sense of how the voice affects his or her quality of life.

Pitch Strength as an Outcome Measure for Treatment of Dysphonia

BACKGROUND

Measurement of treatment outcomes is critical for the spectrum of voice treatments (ie, surgical, behavioral, or pharmacological). Outcome measures typically include visual (eg, stroboscopic data), auditory (eg, Consensus Auditory-Perceptual Evaluation of Voice; Grade, Roughness, Breathiness, Asthenia, Strain), and objective correlates of vocal fold vibratory characteristics, such as acoustic signals (eg, harmonics-to-noise ratio, cepstral peak prominence) or patient self-reported questionnaires (eg, Voice Handicap Index, Voice-Related Quality of Life). Subjective measures often show high variability, whereas most acoustic measures of voice are only valid for signals where some degree of periodicity can be assumed. However, this assumption is often invalid for dysphonic voices where signal periodicity is suspect. Furthermore, many of these measures are not useful in isolation for diagnostic purposes.

OBJECTIVE

We evaluated a recently developed algorithm (Auditory Sawtooth Waveform Inspired Pitch Estimator-Prime [Auditory-SWIPE']) for estimating pitch and pitch strength for dysphonic voices. Whereas fundamental frequency is a physical attribute of a signal, pitch is its psychophysical correlate. As such, the perception of pitch can extend to most signals irrespective of their periodicity.

METHODS

Post hoc analyses were conducted for three groups of patients evaluated and treated for voice problems at a major voice center: (1) muscle tension dysphonia/functional dysphonia, (2) vocal fold mass(es), and (3) presbyphonia. All patients were recorded before and after surgical/behavioral treatment for voice disorders. Pitch and pitch strength for each speaker were computed with the Auditory-SWIPE' algorithm.

RESULTS

Comparison of pre- and posttreatment data provides support for pitch strength as a measure of treatment outcomes for dysphonic voices.

Voice Disorder Classification Based on Multitaper Mel Frequency Cepstral Coefficients Features

The Mel Frequency Cepstral Coefficients (MFCCs) are widely used in order to extract essential information from a voice signal and became a popular feature extractor used in audio processing. However, MFCC features are usually calculated from a single window (taper) characterized by large variance. This study shows investigations on reducing variance for the classification of two different voice qualities (normal voice and disordered voice) using multitaper MFCC features. We also compare their performance by newly proposed windowing techniques and conventional single-taper technique. The results demonstrate that adapted weighted Thomson multitaper method could distinguish between normal voice and disordered voice better than the results done by the conventional single-taper (Hamming window) technique and two newly proposed windowing methods. The multitaper MFCC features may be helpful in identifying voices at risk for a real pathology that has to be proven later.

Reliability of OperaVOX against Multidimensional Voice Program (MDVP)

OBJECTIVE

To evaluate the agreement between OperaVOX and MDVP.

DESIGN

Cross sectional reliability study.

SETTING

University teaching hospital.

METHODS

Fifty healthy volunteers and 50 voice disorder patients had supervised recordings in a quiet room using OperaVOX by the iPod's internal microphone with sampling rate of 45 kHz. A five-seconds recording of vowel/a/was used to measure fundamental frequency (F0), jitter, shimmer and noise-to-harmonic ratio (NHR). All healthy volunteers and 21 patients had a second recording. The recorded voices were also analysed using the MDVP. The inter- and intrasoftware reliability was analysed using intraclass correlation (ICC) test and Bland-Altman (BA) method. Mann-Whitney test was used to compare the acoustic parameters between healthy volunteers and patients.

RESULTS

Nine of 50 patients had severe aperiodic voice. The ICC was high with a confidence interval of >0.75 for the inter- and intrasoftware reliability except for the NHR. For the intersoftware BA analysis, excluding the severe aperiodic voice data sets, the bias (95% LOA) of F0, jitter, shimmer and NHR was 0.81 (11.32, -9.71); -0.13 (1.26, -1.52); -0.52 (1.68, -2.72); and 0.08 (0.27, -0.10). For the intrasoftware reliability, it was -1.48 (18.43, -21.39); 0.05 (1.31, -1.21); -0.01 (2.87, -2.89); and 0.005 (0.20, -0.18), respectively. Normative data from the healthy volunteers were obtained. There was a significant difference in all acoustic parameters between volunteers and patients measured by the Opera-VOX (P < 0.001) except for F0 in females (P = 0.87).

CONCLUSION

OperaVOX is comparable to MDVP and has high internal consistency for measuring the F0, jitter and shimmer of voice except for the NHR.

Integrating voice evaluation: correlation between acoustic and audio-perceptual measures

OBJECTIVES/HYPOTHESIS

This article aims to establish correlations between acoustic and audio-perceptual measures using the GRBAS scale with respect to four different voice analysis software programs.

STUDY DESIGN

Exploratory, transversal.

METHODS

A total of 90 voice records were collected and analyzed with the Dr. Speech (Tiger Electronics, Seattle, WA), Multidimensional Voice Program (Kay Elemetrics, NJ, USA), PRAAT (University of Amsterdam, The Netherlands), and Voice Studio (Seegnal, Oporto, Portugal) software programs. The acoustic measures were correlated to the audio-perceptual parameters of the GRBAS and rated by 10 experts.

RESULTS

The predictive value of the acoustic measurements related to the audio-perceptual parameters exhibited magnitudes ranging from weak (R(2)a=0.17) to moderate (R(2)a=0.71). The parameter exhibiting the highest correlation magnitude is B (Breathiness), whereas the weaker correlation magnitudes were found to be for A (Asthenia) and S (Strain). The acoustic measures with stronger predictive values were local Shimmer, harmonics-to-noise ratio, APQ5 shimmer, and PPQ5 jitter, with different magnitudes for each one of the studied software programs.

CONCLUSIONS

Some acoustic measures are pointed as significant predictors of GRBAS parameters, but they differ among software programs. B (Breathiness) was the parameter exhibiting the highest correlation magnitude.

Effects of immediate feedback on learning auditory perceptual voice quality evaluation

The study investigated the effect of immediate feedback in training listeners to perceive subtle differences in voice quality, a perceptual skill that is important for speech-language pathologists. Sixty naive listeners were randomly assigned to a feedback group (Group F), a no feedback group (Group NF), and a no training group acting as a control group (Group C). The task was to evaluate the severity of a perceptual voice quality (breathiness) by using a reference-matching paradigm. All participants took part in three rating sessions (pre-training, 2 days after training and 1 week after training). Group F and Group NF participated in a training session immediately after the first rating session, where Group F practiced with immediate feedback given and Group NF practice with no immediate feedback given. The results showed that Group F and Group NF had significant improvement after training, but Group F did not retain the improvement in the third rating session. The use of a reference-matching training paradigm without giving frequent immediate feedback is suggested for auditory-perceptual voice evaluation training. The most effective frequency of immediate feedback is yet to be determined.

Nonlinear dynamic-based analysis of severe dysphonia in patients with vocal fold scar and sulcus vocalis

OBJECTIVE

The primary goal of this study was to evaluate a nonlinear dynamic approach to the acoustic analysis of dysphonia associated with vocal fold scar and sulcus vocalis.

STUDY DESIGN

Case-control study.

METHODS

Acoustic voice samples from scar/sulcus patients and age-/sex-matched controls were analyzed using correlation dimension (D2) and phase plots, time-domain based perturbation indices (jitter, shimmer, signal-to-noise ratio [SNR]), and an auditory-perceptual rating scheme. Signal typing was performed to identify samples with bifurcations and aperiodicity.

RESULTS

Type 2 and 3 acoustic signals were highly represented in the scar/sulcus patient group. When data were analyzed irrespective of signal type, all perceptual and acoustic indices successfully distinguished scar/sulcus patients from controls. Removal of type 2 and 3 signals eliminated the previously identified differences between experimental groups for all acoustic indices except D2. The strongest perceptual-acoustic correlation in our data set was observed for SNR and the weakest correlation was observed for D2.

CONCLUSIONS

These findings suggest that D2 is inferior to time-domain based perturbation measures for the analysis of dysphonia associated with scar/sulcus; however, time-domain based algorithms are inherently susceptible to inflation under highly aperiodic (ie, type 2 and 3) signal conditions. Auditory-perceptual analysis, unhindered by signal aperiodicity, is therefore a robust strategy for distinguishing scar/sulcus patient voices from normal voices. Future acoustic analysis research in this area should consider alternative (e.g., frequency- and quefrency-domain based) measures alongside additional nonlinear approaches.

Updating signal typing in voice: addition of type 4 signals

The addition of a fourth type of voice to Titze's voice classification scheme is proposed. This fourth voice type is characterized by primarily stochastic noise behavior and is therefore unsuitable for both perturbation and correlation dimension analysis. Forty voice samples were classified into the proposed four types using narrowband spectrograms. Acoustic, perceptual, and correlation dimension analyses were completed for all voice samples. Perturbation measures tended to increase with voice type. Based on reliability cutoffs, the type 1 and type 2 voices were considered suitable for perturbation analysis. Measures of unreliability were higher for type 3 and 4 voices. Correlation dimension analyses increased significantly with signal type as indicated by a one-way analysis of variance. Notably, correlation dimension analysis could not quantify the type 4 voices. The proposed fourth voice type represents a subset of voices dominated by noise behavior. Current measures capable of evaluating type 4 voices provide only qualitative data (spectrograms, perceptual analysis, and an infinite correlation dimension). Type 4 voices are highly complex and the development of objective measures capable of analyzing these voices remains a topic of future investigation.

Objective acoustic analysis of pathological voices from patients with vocal nodules and polyps

OBJECTIVE

We aim to examine the abilities of objective acoustic analysis methods (nonlinear dynamic and traditional perturbation measures) to describe voices from individuals with vocal nodules and polyps.

SUBJECTS AND METHODS

Sustained vowel recordings from normal subjects, patients with vocal nodules, and patients with vocal polyps were analyzed. Perturbation measures of jitter and shimmer were obtained with the Multi-Dimensional Voice Program (MDVP) and CSpeech. Signal-to-noise ratio was calculated using CSpeech. Nonlinear dynamic measures of phase space reconstruction and correlation dimension were also applied to analyze the voices.

RESULTS

A significant difference between normal and polyp groups was found in jitter and shimmer obtained from MDVP, as well as in jitter and signal-to-noise ratio from CSpeech. However, no parameters significantly differentiated between normal and nodule groups. Shimmer from CSpeech did not reveal any significant differences among any of the groups. Correlation dimension values for the nodule and polyp groups were significantly higher than the normal group.

CONCLUSION

Nonlinear dynamic analysis has great potential value for the characterization of voice from patients with vocal nodules and polyps. The combination of traditional perturbation and nonlinear dynamic measures may improve our ability to provide objective clinical analysis of voices with vocal mass lesions.

The Evolution of Diagnosing Benign Vocal Fold Lesions: From Vague to Specific

The evaluation and treatment process for dysphonia due to benign vocal fold lesions (BVFL) can often be a complex and confusing process for clinicians as well as patients. There is no one perfect method, and there are many different approaches to this problem. It is our goal to share our multidisciplinary team evaluation process, decision-making approach, and treatment for patients with these types of voice fold lesions. Our goal is to highlight the teamwork and cross disciplinary cooperation that optimizes patient evaluation and care.

Computer-aided technique for automatic determination of the relationship between transglottal pressure change and voice fundamental frequency

OBJECTIVES

The effect of artificially altered transglottal pressures on the voice fundamental frequency (F0) is known to be associated with vocal fold stiffness. Its measurement, though useful as a potential diagnostic tool for noncontact assessment of vocal fold stiffness, often requires manual and painstaking determination of an unstable F0 of voice. Here, we provide a computer-aided technique that enables one to carry out the determination easily and accurately.

METHODS

Human subjects vocalized in accordance with a series of reference sounds from a speaker controlled by a computer. Transglottal pressures were altered by means of a valve embedded in a mouthpiece. Time-varying vocal F0 was extracted, without manual procedures, from a specific range of the voice spectrum determined on the basis of the controlled reference sounds.

RESULTS

The validity of the proposed technique was assessed for 11 healthy subjects. Fluctuating voice F0 was tracked automatically during experiments, providing the relationship between transglottal pressure change and F0 on the computer.

CONCLUSIONS

The proposed technique overcomes the difficulty in automatic determination of the voice F0, which tends to be transient both in normal voice and in some types of pathological voice.

Voice outcomes after radiotherapy treatment for early glottic cancer: assessment using multidimensional tools

BACKGROUND

This is the first prospective study to use instrumental and both clinician- and client-rated auditory-perceptual measures to examine voice and voice-related quality of life changes in patients after curative radiotherapy for early glottic cancer.

METHOD

Thirty patients undergoing curative radiotherapy treatment for early glottic cancer completed the following: 3 voice tasks for acoustic, aerodynamic, and auditory-perceptual voice measures (therapist-rated); a patient self-report rating of voice quality; and a voice-related quality of life assessment before and 12 months after radiotherapy.

RESULTS

Patients' perceptions of their voice quality and their voice-related quality of life significantly improved posttreatment, as did acoustic, aerodynamic, and auditory-perceptual voice measures. Mean speaking fundamental frequency did not change significantly, although breathiness and strain in the voice recordings were demonstrably reduced.

CONCLUSION

In describing postradiotherapy voices in this study, pertinent measures of voice outcomes have been established, setting the benchmark for comparison in future cohort studies.