Effects of Vocal Intensity and Vowel Type on Cepstral Analysis of Voice

The Accompanying Effect in Responses to Auditory Perturbations: Unconscious Vocal Adjustments to Unperturbed Parameters

PURPOSE

The present study examined whether participants respond to unperturbed parameters while experiencing specific perturbations in auditory feedback. For instance, we aim to determine if speakers adjust voice loudness when only pitch is artificially altered in auditory feedback. This phenomenon is referred to as the "accompanying effect" in the present study.

METHOD

Thirty native Mandarin speakers were asked to sustain the vowel /ɛ/ for 3 s while their auditory feedback underwent single shifts in one of the three distinct ways: pitch shift (±100 cents; coded as PT), loudness shift (±6 dB; coded as LD), or first formant (F1) shift (±100 Hz; coded as FM). Participants were instructed to ignore the perturbations in their auditory feedback. Response types were categorized based on pitch, loudness, and F1 for each individual trial, such as Popp_Lopp_Fopp indicating opposing responses in all three domains.

RESULTS

The accompanying effect appeared 93% of the time. Bayesian Poisson regression models indicate that opposing responses in all three domains (Popp_Lopp_Fopp) were the most prevalent response type across the conditions (PT, LD, and FM). The more frequently used response types exhibited opposing responses and significantly larger response curves than the less frequently used response types. Following responses became more prevalent only when the perturbed stimuli were perceived as voices from someone else (external references), particularly in the FM condition. In terms of isotropy, loudness and F1 tended to change in the same direction rather than loudness and pitch.

CONCLUSION

The presence of the accompanying effect suggests that the motor systems responsible for regulating pitch, loudness, and formants are not entirely independent but rather interconnected to some degree.

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.

Longitudinal Evaluation of Cepstral Peak Prominence in Children

OBJECTIVES

To evaluate whether the acoustic measure of cepstral peak prominence changes during typical development in children 2-7.

METHODS

Data were retrospectively analyzed from the Arizona Child Acoustic Database Repository in this longitudinal cohort study. The Repository contains longitudinal data recordings from 63 total children between 2 and 7 years of age. Thirty-one children met the inclusion criteria for the current analysis (at least five time points of usable speech data, no history of speech or language difficulties, no significant dysphonia, and were monolingual speakers of American English). Cepstral peak prominence measures were calculated in Praat for each child, at each timepoint. Additional acoustic measures of vocal fundamental frequency, vocal intensity, and stimuli length were also calculated. These measures were chosen as previous work has shown they may impact cepstral peak prominence values.

RESULTS

Linear mixed-effects regression models examined the relationship between cepstral peak prominence and age, after controlling for vocal fundamental frequency, vocal intensity, and stimuli length. Within-participant effects of age were found, indicating a trajectory change in which cepstral peak prominence increases with age in this population. This positive relationship between a cepstral peak prominence and age was nonlinear, with a steeper slope between age and cepstral peak prominence after 5 years of age.

CONCLUSIONS

This is the first study to examine the typical developmental trajectory of cepstral peak prominence children between 2 and 7 years, a critical period of vocal development. Cepstral peak prominence increased with age, suggesting an increase in periodicity of vocal fold vibration that coincides with the significant vocal fold structural changes occurring during this time. Outcomes present important normative information on vocal development, essential for effectively understanding the difference between what vocal changes are part of normative development and what changes indicate a voice disorder.

CPPS and Voice-Source Parameters: Objective Analysis of the Singing Voice

INTRODUCTION

In recent years cepstral analysis and specific cepstrum-based measures such as smoothed cepstral peak prominence (CPPS) has become increasingly researched and utilized in attempts to determine the extent of overall dysphonia in voice signals. Yet, few studies have extensively examined how specific voice-source parameters affect CPPS values.

OBJECTIVE

Using a range of synthesized tones, this exploratory study sought to systematically analyze the effect of fundamental frequency (fo), vibrato extent, source-spectrum tilt, and the amplitude of the voice-source fundamental on CPPS values.

MATERIALS AND METHODS

A series of scales were synthesised using the freeware Madde. Fundamental frequency, vibrato extent, source-spectrum tilt, and the amplitude of the voice-source fundamental were systematically and independently varied. The tones were analysed in PRAAT, and statistical analyses were conducted in SPSS.

RESULTS

CPPS was significantly affected by both fo and source-spectrum tilt, independently. A nonlinear association was seen between vibrato extent and CPPS, where CPPS values increased from 0 to 0.6 semitones (ST), then rapidly decreased approaching 1.0 ST. No relationship was seen between the amplitude of the voice-source fundamental and CPPS.

CONCLUSION

The large effect of fo should be taken into account when analyzing the voice, particularly in singing-voice research, when comparing pre and posttreatment data, and when comparing inter-subject CPPS data.

Exploring the Relationship Between Acoustic Measurements and Self-Perception of Voice in Trans Women

OBJECTIVE

This study aimed to explore the strength and direction of the relationship between spectral cepstral-based, time-based acoustic measures and the self-perception of voice in trans women.

METHODS

Forty-eight trans women were included in the study. Analysis of the sustained vowel phonation was performed using Multidimensional Voice Profile Analysis (MDVP), and spectral-cepstral analyses of the sustained vowel phonation, all-voiced weighted sentence, and spontaneous speech were made via Analysis of Dysphonia in Speech and Voice (ADSV) software. For self-perceptual evaluations, the Trans Woman Voice Questionnaire (TWVQ) and the Self-perception of Voice Femininity Scale (SPVF) were used. The correlation between MDVP, spectral-cepstral parameters, and TWVQ and SPVF scores was calculated.

RESULTS

The present study found a positive relationship between F0, SPVF, and TWVQ. Among the perturbation parameters, the jitter was the only one found to correlate with SPVF and TWVQ. The CPPF0 parameter was found to be associated with a more feminine voice perception and a higher voice-related quality of life in all speech samples in the present study. In addition, higher CPP values achieved from vowel phonation were associated with less feminine voice perception and lower voice-related quality of life. The present study also suggests a weak correlation with the SPVF and Cepstral Peak Prominence Standard Deviation (CPPF0 SD) of the spontaneous speech sample in a negative direction.

CONCLUSIONS

This study found weak and moderate levels of correlations between F0, jitter (%), CPP, CPPF0, CPPF0 SD parameters, and self-perceptual measures. These findings suggested that such a level of relationship is attributable to the fact that these tools evaluate different aspects of voice in accordance with the International Classification of Functioning System. According to this pioneering study, it would be beneficial to incorporate spectral-cepstral measures into the objective assessment protocol for trans women's voices.

Sex Differences in the Speech of Persons With and Without Parkinson's Disease

BACKGROUND

Sex differences are apparent in the prevalence and the clinical presentation of Parkinson's disease (PD), but their effects on speech have been less studied.

METHOD

Speech acoustics of persons with (34 females and 34 males) and without (age- and sex-matched) PD were examined, assessing the effects of PD diagnosis and sex on ratings of dysarthria severity and acoustic measures of phonation (fundamental frequency standard deviation, smoothed cepstral peak prominence), speech rate (net syllables per second, percent pause ratio), and articulation (articulatory-acoustic vowel space, release burst precision).

RESULTS

Most measures were affected by PD (dysarthria severity, fundamental frequency standard deviation) and sex (smoothed cepstral peak prominence, net syllables per second, percent pause ratio, articulatory-acoustic vowel space), but without interactions between them. Release burst precision was differentially affected by sex in PD. Relative to those without PD, persons with PD produced fewer plosives with a single burst: females more frequently produced multiple bursts, whereas males more frequently produced no burst at all.

CONCLUSIONS

Most metrics did not indicate that speech production is differentially affected by sex in PD. Sex was, however, associated with disparate effects on release burst precision in PD, which deserves further study.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24388666.

Are smartphones and low-cost external microphones comparable for measuring time-domain acoustic parameters?

PURPOSE

This study examined and compared the diagnostic accuracy and correlation levels of the acoustic parameters of the audio recordings obtained from smartphones on two operating systems and from dynamic and condenser types of external microphones.

METHOD

The study included 87 adults: 57 with voice disorder and 30 with a healthy voice. Each participant was asked to perform a sustained vowel phonation (/a/). The recordings were taken simultaneously using five microphones AKG-P220, Shure-SM58, Samson Go Mic, Apple iPhone 6, and Samsung Galaxy J7 Pro microphones in an acoustically insulated cabinet. Acoustic examinations were performed using Praat version 6.2.09. The data were examined using Pearson correlation and receiver-operating characteristic (ROC) analyses.

RESULTS

The parameters with the highest area under curve (AUC) values among all microphone recordings in the time-domain analyses were the frequency perturbation parameters. Additionally, considering the correlation coefficients obtained by synchronizing the microphones with each other and the AUC values together, the parameter with the highest correlation coefficient and diagnostic accuracy values was the jitter-local parameter.

CONCLUSION

Period-to-period perturbation parameters obtained from audio recordings made with smartphones show similar levels of diagnostic accuracy to external microphones used in clinical conditions.

Cepstral Measurements: A Comparison of Results Between Singing and Non-Singing Individuals

OBJECTIVE

To analyze and compare cepstral measurements in singing and non-singing men and women to understand if vocal adaptations of singers reflect greater cepstral measurement results.

METHOD

The study included 91 vocally healthy individuals, consisting of 60 erudite or popular singers (30 males, 30 females) and 31 non-singers (16 males, 15 females). The Cepstral Peak Prominence (CPP) and Cepstral Peak Prominence-Smoothed (CPPS) measures were carried out using the sustained /a/ vowel recorded with a unidirectional condenser microphone associated with a sound card on the computer. The Praat software (version 6.1.16) was used to extract the CPP and CPPS measurements. The intra and intergroup values obtained for each sex were compared using the t-test with a 5% significance level.

RESULTS

There was a CPP (P = 0,000) and CPPS (P = 0,000 and P = 0,001) value difference between the sexes in both groups. Cepstral measurements showed no statistically significant difference between singing and non-singing participants (male: P = 0,778 and P = 0,622; female: P = 0,622 and P = 0,460).

CONCLUSION

Men presented higher CPP and CPPS values than women, which may be related to the presence of the physiological posterior glottic cleft in women. The knowledge of the cepstral values of singers shows that singing specificities may not reflect in all vocal evaluations.

Normative Values of Cepstral Peak Prominence Measures in Typical Speakers by Sex, Speech Stimuli, and Software Type Across the Life Span

PURPOSE

The purpose of this study was to determine normative values for cepstral peak prominence measures across the life span as a function of sex using clinically relevant stimuli (/ɑ/, /i/, and two sentences of The Rainbow Passage) and two commonly used software types: Praat (Version 6.0.50) and Analysis of Dysphonia in Speech and Voice (ADSV).

METHOD

One hundred fifty speakers (75 males, 75 females; evenly distributed into three age groups) without voice disorders aged 18-91 years were recorded via headset microphone in a sound-treated booth. Cepstral measures were analyzed using common analysis methods in Praat and ADSV by sex, stimuli, and software type. Kruskal-Wallis tests and post hoc Mood's Median tests for significant factors were performed on cepstral measures to assess the effects of age group, sex, stimuli, and software type.

RESULTS

The results revealed statistically significant effects of sex, stimuli, and software type on cepstral measures, but no statistical effect of age group on cepstral values. Females had lower average cepstral values compared to males. Across stimuli, the highest average cepstral measure was found for sustained /ɑ/, followed by sustained /i/, and then of the two sentences of The Rainbow Passage. Average cepstral measures in Praat were higher than those from ADSV.

CONCLUSIONS

The current work did not find a statistical effect of age group on cepstral values; thus, normative cepstral values were reported by sex, stimuli, and software type. Future work should examine the applicability of these normative values for discriminating speakers with and without voice disorders.

Impact of naturalistic smartphone positioning on acoustic measures of voicea)

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

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.

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.

Acoustic Measures of Dysphonia in Amyotrophic Lateral Sclerosis

PURPOSE

Identifying efficacious measures to characterize dysphonia in complex neurodegenerative diseases is key to optimal assessment and intervention. This study evaluates the validity and sensitivity of acoustic features of phonatory disruption in amyotrophic lateral sclerosis (ALS).

METHOD

Forty-nine individuals with ALS (40-79 years old) were audio-recorded while producing a sustained vowel and continuous speech. Perturbation/noise-based (jitter, shimmer, and harmonics-to-noise ratio) and cepstral/spectral (cepstral peak prominence, low-high spectral ratio, and related features) acoustic measures were extracted. The criterion validity of each measure was assessed using correlations with perceptual voice ratings provided by three speech-language pathologists. Diagnostic accuracy of the acoustic features was evaluated using area-under-the-curve analysis.

RESULTS

Perturbation/noise-based and cepstral/spectral features extracted from /a/ were significantly correlated with listener ratings of roughness, breathiness, strain, and overall dysphonia. Fewer and smaller correlations between cepstral/spectral measures and perceptual ratings were observed for the continuous speech task, although post hoc analyses revealed stronger correlations in speakers with less perceptually impaired speech. Area-under-the-curve analyses revealed that multiple acoustic features, particularly from the sustained vowel task, adequately differentiated between individuals with ALS with and without perceptually dysphonic voices.

CONCLUSIONS

Our findings support using both perturbation/noise-based and cepstral/spectral measures of sustained /a/ to assess phonatory quality in ALS. Results from the continuous speech task suggest that multisubsystem involvement impacts cepstral/spectral analyses in complex motor speech disorders such as ALS. Further investigation of the validity and sensitivity of cepstral/spectral measures during continuous speech in ALS is warranted.

Investigation of the Cepstral Spectral Acoustic Analysis for Classifying the Severity of Dysphonia

OBJECTIVES

The advantages of cepstral measurements in the evaluation of dysphonia have been noted in previous studies. However, there is an unclarity regarding the results of cepstral analyzes effect in determining the severity of dysphonia. The aims of this study were to determine the cut-off values of cepstral peak prominence, cepstral peak prominence standard deviation, low frequency/ high frequency ratio, low frequency/high frequency ratio standard deviation, and cepstral spectral index of dysphonia for predicting the voice severity within a Turkish speaking population, as well as to confirm the discriminative power of these cut-off values.

MATERIALS METHODS

One hundred ninety-five individuals with voice disorders and an equal number of age and gender-matched individuals without voice disorders were included. Included subjects had visited the Hacettepe University Hospitals Speech and Language Therapy Department for voice evaluation between January 2017 and September 2021. The voice recordings from all participants included the six CAPE-V/Turkish sentences and sustained vowel /a/. Three raters provided auditory perceptual ratings of the voice samples using the GRBAS scale (grade) and overall severity for the CAPE-V/Turkish. Participants were categorized into normal and mild, moderate, and severely dysphonic groups based on the auditory perceptual evaluation. Analysis of Dysphonia in Speech and Voice (ADSV) software was used for cepstral spectral acoustic analysis.

RESULTS

In the sustained vowel context, the area under the curve (ROC) for the CSID value was >0.8, except for mild vs. moderate dysphonia groups. In connected speech contexts, the ROC of the CPP value was also >0.8, except for normal vs. mild dysphonia groups. The cut-off values of CPP and CSID demonstrated high sensitivity and specificity for predicting voice severities.

CONCLUSION

The cut-off values for the parameters that predicted voice severities showed a significant degree of discriminative power for categorizing voice severities among Turkish-speaking people.

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.

The Effect of Pitch and Loudness Auditory Feedback Perturbations on Vocal Quality During Sustained Phonation

OBJECTIVE

Dysphonia is a reduction in vocal quality that impacts communication and is often an early sign of a voice disorder. There is little information regarding the effects of auditory feedback control of loudness and pitch on voice quality. In this study, we used both loudness-shift and pitch-shift paradigms to study the relationship between auditory feedback control and vocal quality as measured by smoothed cepstral peak prominence (CPPS), which reflects the harmonicity of the voice signal.

STUDY DESIGN

Experimental, mixed design.

METHODS

We applied 200 ms loudness-shifts (± 0, 3, or 6 dB) and pitch-shifts (± 0, 50, and 100 cents) to auditory feedback during sustained vowel production in 25 healthy adults. We then measured CPPS before and after the loudness-shift or pitch-shift to investigate the effect of changes in auditory feedback on vocal harmonicity.

RESULTS & CONCLUSIONS

Results showed that, on average, CPPS significantly decreased between the first half of the measured segment and the last half of the segment in the absence of auditory feedback shifts, suggesting that voice quality may be reduced across longer vowels over time. Upward and downward shifts in loudness auditory feedback caused a relative increase in CPPS, indicating an improvement in vocal harmonicity, even in cases when vocal intensity was reduced. Pitch alterations had inconsistent and minimal effects. We propose that there may be a control mechanism for voice quality that increases harmonicity of the voice signal to improve voice audibility (ie, ability to be heard) in the presence of unpredictable variability in voice intensity.

A Practical Guide to Calculating Cepstral Peak Prominence in Praat

The acoustic measure of cepstral peak prominence (CPP) is recommended for the analysis of dysphonia. Yet, clinical use of this measure is not universal, as clinicians and researchers are still learning the strengths and limitations of this measure. Furthermore, affordable access to specialized acoustic software is a significant barrier to universal CPP use. This article will provide a guide on how to calculate CPP in Praat, a free software program, using a new CPP plugin. Important external factors that could influence CPP measures are discussed, and suggestions for clinical use are provided. As CPP becomes more widely used by clinicians and researchers, it is important to consider external factors that may inadvertently influence CPP values. Controlling for these external factors will aid in reducing variability across CPP values, which will make CPP a valuable tool for both clinical and research purposes.

The effects of vocal exertion on lung volume measurements and acoustics in speakers reporting high and low vocal fatigue

Purpose

Vocal exertion is common and often results in reduced respiratory and laryngeal efficiency. It is unknown, however, whether the respiratory kinematic and acoustic adjustments employed during vocal exertion differ between speakers reporting vocal fatigue and those who do not. This study compared respiratory kinematics and acoustic measures in individuals reporting low and high levels of vocal fatigue during a vocal exertion task.

Methods

Individuals reporting low (N = 20) and high (N = 10) vocal fatigue participated in a repeated measures design study over 2 days. On each day, participants completed a 10-minute vocal exertion task consisting of repeated, loud vowel productions at elevated F0 sustained for maximum phonation time. Respiratory kinematic and acoustic measures were analyzed on the 1^st vowel production (T0), and the vowels produced 2 minutes (T2), 5 minutes (T5), 7 minutes (T7), and 10 minutes (T10) into the vocal exertion task. Vowel durations were also measured at each time point.

Results

No differences in respiratory kinematics were observed between low and high vocal fatigue groups at T0. As the vocal exertion task progressed (T2-T10), individuals reporting high vocal fatigue initiated phonation at lower lung volumes while individuals with low vocal fatigue initiated phonation at higher lung volumes. As the exertion task progressed, total lung volume excursion decreased in both groups. Differences in acoustic measures were observed, as individuals reporting high vocal fatigue produced softer, shorter vowels from T0 through T10.

Conclusions

Individuals reporting high vocal fatigue employed less efficient respiratory strategies during periods of increased vocal demand when compared with individuals reporting low vocal fatigue. Individuals reporting high vocal fatigue had shorter maximum phonation time on loud vowels. Further study should examine the potential screening value of loud maximum phonation time, as well as the clinical implications of the observed respiratory patterns for managing vocal fatigue.

The Effect of Mandarin Vowels on Acoustic Analysis: A Prospective Observational Study

OBJECTIVES

Although vowels are of interest for acoustic analysis in clinics, there is no consensus regarding the effect of vowel selection on acoustic perturbation parameters. This study aimed to reveal the effects of Mandarin vowels on acoustic measurements.

STUDY DESIGN

A prospective observational study.

METHODS

This prospective observational study enrolled normal phonation Mandarin speakers at the Otolaryngology Department of the Eye & ENT Hospital affiliated with Fudan University from December 2020 to August 2021. This study recruited 107 normal-voiced Mandarin speakers (59 women and 49 men) with a median age of 26 (22, 33) years old. The objective measures included traditional acoustic parameters (fundamental frequency, harmonic-to-noise ratio, percent jitter, and percent shimmer) and cepstral analysis (smoothed cepstral peak prominence) of six Mandarin vowels (ɑ /a/, o /o/, e /ɤ/, i /i/, u /u/, ü /y/).

RESULTS

The acoustic analysis revealed no significant differences in the fundamental frequency among vowels. The low vowel /a/ had the highest values for percent jitter and percent shimmer and the lowest harmonic-to-noise ratio value. The back vowel /u/ had the lowest cepstral measures (P < 0.05).

CONCLUSIONS

The acoustic analysis significantly varied across the different Mandarin vowels, and these differences must be considered for the effective clinical application of objective evaluations.

Impact of Face Masks on Speech Acoustics and Vocal Effort in Healthcare Professionals

OBJECTIVES/HYPOTHESIS

We investigated speech acoustics and self-reported vocal symptoms in mask-wearing healthcare professionals. We hypothesized that there would be an attenuation of spectral energies and increase in vocal effort during masked speech compared to unmasked speech.

STUDY DESIGN

Within and between subject quasi-experimental design.

METHODS

We prospectively enrolled 21 healthcare providers (13 cisgender female, 8 cisgender male; M = 32.9 years; SD = 7.9 years) and assessed acoustics and perceptual measures with and without a face mask in place. Measurements included: 1) acoustic Vowel Articulation Index (VAI); 2) cepstral and spectral acoustic measures; 3) traditional vocal measures (e.g., fundamental frequency, intensity); 4) relative fundamental frequency (RFF); and 5) self-reported ratings of vocal effort and dyspnea.

RESULTS

During masked speech, there was a significant reduction in VAI, high-frequency information (>4 kHz), and RFF offset 10, as well as a significant increase in cepstral peak prominence and perceived vocal effort. Further analysis showed that high-frequency attenuation was more pronounced when wearing an N95 mask compared to a simple mask.

CONCLUSIONS

Face masks pose an additional barrier to effective communication that primarily impacts spectral characteristics, vowel space measures, and vocal effort. Future work should evaluate how long-term mask use impacts vocal health and may contribute to vocal problems.

LEVEL OF EVIDENCE

3 Laryngoscope, 132:391-397, 2022.

The reproducibility of bio-acoustic features is associated with sample duration, speech task and gender

Bio-acoustic properties of speech show evolving value in analyzing psychiatric illnesses. Obtaining a sufficient speech sample length to quantify these properties is essential, but the impact of sample duration on the stability of bio-acoustic features has not been systematically explored. We aimed to evaluate bio-acoustic features' reproducibility against changes in speech durations and tasks. We extracted source, spectral, formant, and prosodic features in 185 English-speaking adults (98 w, 87 m) for reading-a-story and counting tasks. We compared features at 25% of the total sample duration of the reading task to those obtained from non-overlapping randomly selected sub-samples shortened to 75%, 50%, and 25% of total duration using intraclass correlation coefficients. We also compared the features extracted from entire recordings to those measured at 25% of the duration and features obtained from 50% of the duration. Further, we compared features extracted from reading-a-story to counting tasks. Our results show that the number of reproducible features (out of 125) decreased stepwise with duration reduction. Spectral shape, pitch, and formants reached excellent reproducibility. Mel-frequency cepstral coefficients (MFCCs), loudness, and zero-crossing rate achieved excellent reproducibility only at a longer duration. Reproducibility of source, MFCC derivatives, and voicing probability (VP) was poor. Significant gender differences existed in jitter, MFCC first-derivative, spectral skewness, pitch, VP, and formants. Around 97% of features in both genders were not reproducible across speech tasks, in part due to the short counting task duration. In conclusion, bio-acoustic features are less reproducible in shorter samples and are affected by gender.

Co-Occurrence of Hypernasality and Voice Impairment in Amyotrophic Lateral Sclerosis: Acoustic Quantification

PURPOSE

Hypernasality and atypical voice characteristics are common features of dysarthric speech due to amyotrophic lateral sclerosis (ALS). Existing acoustic measures have been developed to primarily target either hypernasality or voice impairment, and the effects of co-occurring hypernasality-voice problems on these measures are unknown. This report explores (a) the extent to which acoustic measures are affected by concurrent perceptually identified hypernasality and voice impairment due to ALS and (b) candidate acoustic measures of early indicators of hypernasality and voice impairment in the presence of multisystem involvement in individuals with ALS.

METHOD

Two expert listeners rated severity of hypernasality and voice impairment in sentences produced by individuals with ALS (n = 27). The samples were stratified based on perceptual ratings: voice/hypernasality asymptomatic, predominantly hypernasal, predominantly voice impairment, and mixed (co-occurring hypernasality and voice impairment). Groups were compared using established acoustic measures of hypernasality (one-third octave analysis) and voice (cepstral/spectral analysis) impairment.

RESULTS

The one-third octave analysis differentiated all groups; the cepstral peak prominence differentiated all groups except asymptomatic versus mixed, whereas the low-to-high spectral ratio did not differ among groups. Additionally, one-third octave analyses demonstrated promising speech diagnostic potential.

CONCLUSIONS

The results highlight the need to consider the validity of measures in the context of multisubsystem involvement. Our preliminary findings further suggest that the one-third octave analysis may be an optimal approach to quantify hypernasality and voice abnormalities in the presence of multisystem speech impairment. Future evaluation of the diagnostic accuracy of the one-third octave analysis is warranted.

Contribution of laryngeal size to differences between male and female voice production

In this study we investigated the effect of sex- and age-related differences in vocal fold length, thickness, and depth on voice production in a three-dimensional vocal fold model. The results showed that the cause-effect relationships between vocal fold physiology and voice production previously identified in an adult male-like vocal fold geometry remained qualitatively the same in vocal folds with geometry representative of adult females and children. We further showed that the often-observed differences in voice production between adult males, adult females, and children can be explained by differences in length and thickness. The lower F0, higher flow rate, larger vocal fold vibration amplitude, and higher sound pressure level (SPL) in adult males as compared to adult females and children can be explained by differences in vocal fold length. In contrast, the thickness effect dominated and contributed to the larger closed quotient of vocal fold vibration, larger normalized maximum flow declination rate, and lower H1-H2 in adult males as compared to adult females and children. The effect of differences in vocal fold depth was generally small. When targeting a specific SPL, adult males experienced a lower peak vocal fold contact pressure during phonation than adult females and children.

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.

Receiver operating characteristic analysis of acoustic and electroglottographic parameters with different sustained vowels

OBJECTIVE

To examine the power of the parameters obtained from different sustained vowels used in acoustic and electroglottographic (EGG) voice evaluation protocols to discriminate between dysphonic and non-dysphonic voice quality.

METHODS

Sixty non-dysphonic participants and 30 dysphonic participants were included in the study. In addition to the time domain amplitude and frequency perturbation parameters obtained from the sustained phonation of /ʌ/-/ɛ/-/i/-/u/ vowels, several frequency-domain spectral/cepstral parameters and EGG parameters were evaluated. The classification performance of the acoustic and electroglottographic measures was quantified using analysis and receiver operating characteristic (ROC) curve analysis.

RESULTS

As a result of ROC analysis, the discriminative diagnostic performance (area under the curve, AUC) of the test for low-vowel (/ʌ/-/ɛ/) phonation was higher than values obtained from high-vowel (/i/-/u/) phonation. For /ʌ/ and /ɛ/ sustained vowels, the parameters exhibiting the highest discrimination were fundamental frequency standard deviation (f_o/STD), cepstral peak prominence (CPP), relative average perturbation (RAP), pitch perturbation quotient (PPQ), and jitter percent (JITT). In the EGG parameters, on the other hand, average jitter and periodicity parameters obtained from front vowels (/ɛ/-/i/) were found to have higher AUC values compared to back vowels (/ʌ/-/u/).

CONCLUSIONS

In acoustic analyses, /ʌ/ and /ɛ/ sustained vowels give the highest diagnostic performance. In the electroglottographic evaluation, on the other hand, /ɛ/ and /i/ vowels, when the position of the tongue is forward, have better classification performance compared to /ʌ/ and /u/ vowels, when the position of the tongue is back.

Investigating the cepstral acoustic characteristics of voice in healthy children

OBJECTIVES

This study aimed to determine the cepstral acoustic parameters that vary depending on age and gender in vocally healthy children, and to establish normative data for cepstral analysis.

BACKGROUND

Cepstral measurements are among the strongest predictors of auditory-perceptual evaluation of voice and differentiate between healthy and dysphonic voices. More spesificially, ceptral peak prominence is accepted to be as a strong acoustic predictor of breathiness and overall severity of dysphonia. Cepstral measures determine voice quality reliably not only in sustained vowel samples but also in running speech samples. Determining the parameters related to the acoustic profile of children with normal voices can lead us to a better understanding of the effect of changes in the larynx and vocal fold structure during growth and development. There is a limited number of norm studies examining the cepstral acoustic properties of pediatric voice. Determining norm-specific values and clinical guidelines of cepstral acoustics according to the age and gender in vocally healthy children are utmost important.

METHODS

A total of 160 vocally healthy children were divided into the following four age groups: Group-I included children within the age range of 4-7 years, Group-II included 7-11 years, Group-III 11-14 years, and Group-IV included children within the age range of 14-18 years. An equal number of male and female participants were assigned to each group. PENTAX Medical CSL Model 4500 was used for recording all tasks. For acoustic analysis, Multi-Dimensional Voice Program and Analysis of Dysphonia in Speech and Voice were used.

RESULTS

Cepstral Peak Prominence (CPP), Cepstral Peak Prominence Standard Deviation (CPP SD), and Low-To-High Spectral Ratio (L/H Ratio) increased with age. It is found that the CPP parameter of all-voiced sentences and nasal-weighted sentences increased with age in boys, while no significant pattern was observed in any sample for girls. For L/H ratio, it can be said that there is a general increase with age in all speech samples, except for the vowel-weighted and voiceless plosive sentence samples, evident especially in the group above the age of 15 years. This study concluded that the CPP SD parameter in the vowel-weighted sentences increased with age in boys. It was also noticed in this study that CPP F0 standard deviation (SD) intervals were narrower in vowel-weighted, easy onset, and voiceless plosive sentence samples than in all-voiced, hard glottal attack and nasal-weighted sentence samples.

CONCLUSION

This study established cepstral acoustic normative values for a wide age range of the pediatric population. It is thought that age and gender specific cepstral acoustic findings presented in this study contributed to the related literature. In addition, to our knowledge, this is the first study that provides a normative cepstral acoustic database of the CAPE-V/Turkish sentences in the pediatric population.

Acoustic Variability in the Healthy Female Voice Within and Across Days: How Much and Why?

Purpose The aims of this study were (1) to quantify variability in voice production (as measured acoustically) within and across consecutive days in vocally healthy female speakers, (2) to identify which acoustic measures are sensitive to this variability, and (3) to identify participant characteristics related to such voice variability. Method Participants included 45 young women with normal voices who were stratified by age, specifically 18-23, 24-29, and 30-35 years. Following an initial acoustic and auditory-perceptual voice assessment, participants performed standardized field voice recordings 3 times daily across a 7-day period. Acoustic analyses involved 32 cepstral-, spectral-, and time-based measures of connected speech and sustained vowels. Relationships among acoustic data and select demographic, health, and lifestyle (i.e., participant-based) factors were also examined. Results Significant time-of-day effects were observed for acoustic analyses within speakers (p < .05), with voices generally being worse in the morning. No significant differences were observed across consecutive days. Variations in voice production were associated with several participant factors, including improved voice with increased voice use; self-perceived poor voice function, minimal or no alcohol consumption, and extroverted personality; and worse voice with regular or current menstruation, depression, and anxiety. Conclusions This acoustic study provides essential information regarding the nature and extent to which healthy voices vary throughout the day and week. Participant-based factors that were associated with improved voice over time included increased voice use, self-perceived poor voice function, minimal or no alcohol consumption, and extroverted personality. Factors associated with worse voice production over time included regular or current menstruation, and depression and anxiety.

Dysarthria treatment for Parkinson's disease: one-year follow-up of SPEAK OUT!® with the LOUD Crowd®

INTRODUCTION

SPEAK OUT! with The LOUD Crowd is a standardized speech therapy program typically consisting of 12 one-on-one treatments and ongoing weekly group maintenance sessions for patients with dysarthria due to Parkinson's disease (PD). It is based upon the hypothesis that increased attention to speech, which is a goal-directed motor activity, may compensate for the impairment in automatic sequential motor behaviors often demonstrated in patients with PD. We present results on the 1-year response to treatment.

METHODS

Forty individuals with idiopathic PD received SPEAK OUT! delivered in 12 one-on-one 40-min treatment sessions 3 times per week for four consecutive weeks in addition to ongoing group maintenance sessions called The LOUD Crowd. Evaluations occurred 3 times at baseline, within one and six weeks after completion of the SPEAK OUT! sessions (N = 40) and 1-year later (N = 35). Assessments included mean speech intensity and intonation from reading and monolog, the voice quality acoustic measure called cepstral peak prominence (CPP), and scores on the voice-related quality of life questionnaire.

RESULTS

The significant improvements achieved in all outcome measures from baseline to completion of SPEAK OUT! were maintained 1-year later. Participation throughout the year in regular group maintenance sessions (The LOUD Crowd) was positively correlated with level of improvement at 1 year for all measures except patient perception of voice.

CONCLUSIONS

These long-term data contribute evidence of the effectiveness of this speech therapy program for improving communication for individuals with PD and emphasize the importance of regular and ongoing group sessions to sustain therapeutic gains.

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

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

Effects of Vocal Intensity and Fundamental Frequency on Cepstral Peak Prominence in Patients with Voice Disorders and Vocally Healthy Controls

OBJECTIVE

Cepstrum-based voice measures, such as smoothed cepstral peak prominence (CPPS), are influenced by voice sound pressure level (SPL) in vocally healthy adults. Since it is unclear if similar effects hold in voice disordered adults and how these interact with natural fundamental frequency (fo) changes, this study examines voice SPL and fo effects on CPPS in women with vocal hyperfunction and vocally healthy controls.

STUDY DESIGN

Retrospective matched case-control study.

METHODS

Fifty-eight women with vocal hyperfunction were individually matched with 58 vocally healthy women for occupation and approximate age. The patient group comprised women exhibiting phonotraumatic vocal hyperfunction associated with vocal fold nodules (n = 39) or polyps (n = 5), and nonphonotraumatic vocal hyperfunction associated with primary muscle tension dysphonia (n = 14). All participants sustained the vowel /a/ at soft, comfortable, and loud loudness conditions. Voice SPL, fo, and CPPS (dB) were computed from acoustic voice recordings using Praat. The effects of loudness condition, measured voice SPL, and fo on CPPS were assessed with linear mixed models. Pairwise correlations among voice SPL, fo, and CPPS were assessed using multiple regression analysis.

RESULTS

Increasing voice SPL correlated significantly (P < 0.001) with higher CPPS in both patient (r2 = 0.53) and normative groups (r2 = 0.45). fo had statistically significant effects on CPPS (P < 0.001), but with a weak relation for the patient (r2 = 0.02) and control groups (r2 = 0.05).

CONCLUSIONS

In women with and without voice disorder, CPPS is highly affected by the individual's voice SPL in vowel phonation. Future studies could investigate how these effects should be controlled for to improve the diagnostic value of acoustic-based cepstral measures.

A Field-Based Approach to Establish Normative Acoustic Data for Healthy Female Voices

Purpose The primary aim of this study was to obtain high-quality acoustic normative data in natural field environments for female voices. A secondary aim was to examine acoustic measurement variability in field environments. Method This study employed a within-subject repeated-measures experimental design that included 45 young female adults with normal voices. Participants were stratified by age (18-23, 24-29, and 30-35 years). After initial evaluation and instruction, participants completed voice recordings during seven consecutive days using a standard protocol, including both connected speech and sustained vowels. Thirty-two cepstral-, spectral-, and time-based acoustic measures were acquired using Praat and the Analysis of Dysphonia in Speech and Voice. Results Among the 958 total recordings, greater than 90% satisfied inclusion criteria based on protocol compliance, peak clipping, and signal-to-noise ratio. Significant differences were observed for age (p < .05). For 19 acoustic measures, values improved significantly as signal-to-noise ratio increased. Cepstral- and spectral-based measures demonstrated less measurement variability as compared with time-based measures. Conclusions With adequate training, field audio recordings represent a viable option for clinical voice management. The significant age effects observed in this study support the need for more specific criteria when collecting and applying normative data. Cepstral- and spectral-based measures demonstrated the least measurement variability. This study provides additional evidence for multiparameter acoustic voice measurement, specifically toward ecologically valid sampling in natural environments. Future studies should expand on these findings in other populations with normal and disordered voices.

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.

Worldwide Healthy Adult Voice Baseline Parameters: A Comprehensive Review

The voice results in acoustic signals analyzed and synthetized at first for telecommunication matters, and more recently investigated for medical purposes. In particular, voice signal characteristics can evidence individual health conditions useful for screening, diagnostic and remote monitoring aims. Within this frame, the knowledge of baseline features of healthy voice is mandatory, in order to balance a comparison with their unhealthy counterpart. However, the baseline features of the human voice depend on gender, age-range and ethnicity and, as far as we know, no work reports as those features spread worldwide. This paper intends to cover this lack. Our database research yielded 179 relevant published studies, retrieved using digital libraries of IEEE Xplore, Scopus, Web of Science, Iop Science, Taylor and Francis Online, and Scitepress. These relevant studies report different features, among which here we consider the most investigated ones, within the most investigated age-range. In particular, the features are the fundamental frequency, the jitter, the shimmer, the harmonic-to-noise ratio, and the cepstral peak prominence, the most investigated age-range is within 20-40 years and, related to the ethnicity, 20 countries are considered.

The Impact of Communication Modality on Voice Production

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

Are Indoor Cycling Instructors Riding Their Way to Vocal Injury? Acute Effects of a Single Class on Measures of Voice Production

OBJECTIVE/HYPOTHESIS

There is an increased need for vocal education programs in group fitness instructors due to the reported risk of phonotraumatic injury in this population. Most research has focused on aerobics class instructors with limited research detailing the vocal demand response of cycling instruction, specifically. We hypothesized that instruction of a single indoor cycling class would produce evidence of acute vocal fold edema manifested by worsening of acoustic and self-perceptual voice measures and changes in ratings of laryngeal appearance.

STUDY DESIGN

Prospective Cohort study.

METHODS

Acoustic and self-perceptual voice measures that were potentially sensitive to laryngeal edema were collected from ten cycling instructors (Mean age: 31 ± 6.14 years, 3M and 7F) before and after instruction of a typical 45-minute cycling class. Two laryngologists then rated pairs of laryngeal exams from five instructors (Mean age: 30 ± 6.22 years, 1M and 4F) on the measure of vocal fold edema using a 10-inch Visual Analogue Scale. Paired t-test comparisons were completed on normalized data to compare pre- and postinstruction.

RESULTS

Majority of acoustic and self-perceptual measures significantly worsened following cycling instruction but the magnitude of change in these measures were small. In terms of laryngeal appearance, no measurable change in vocal fold edema was observed at both time points.

CONCLUSION

The vocal demand response to a single cycling class may be insufficient to cause significant vocal fold edema in our cycling instructors. Future research is required to determine the effects of repeated cycling instruction.

The Effect of SPEAK OUT! and The LOUD Crowd on Dysarthria Due to Parkinson's Disease

Purpose SPEAK OUT! and The LOUD Crowd is a standardized speech therapy program of 12 individual treatments combined with ongoing weekly group sessions for individuals with dysarthria due to Parkinson's disease (PD). The premise of this program is that individuals with PD must rely on goal-directed basal ganglia-cortical circuits to compensate for deficits in habitual, automatic control. The purpose of this study was to assess the outcome of this therapy program. Method Forty individuals with idiopathic PD received SPEAK OUT! in 12 individual 40-min sessions 3 times per week for 4 consecutive weeks and also participated in The LOUD Crowd. Assessments were conducted 3 times at baseline and then within 1 and 6 weeks after completion of the individual SPEAK OUT! sessions. Twenty-five adults without communication disorders were assessed on the same schedule. Acoustic outcome measures were mean intensity from reading and monologue, the prosody measures of standard deviation of intensity and frequency from reading and monologue, and the voice quality measure of cepstral peak prominence from reading. Patient perception of voice was also assessed with the Voice-Related Quality of Life. Results Posttherapy, mean intensity was greater and variation of frequency was larger in reading and monologue, while variation in intensity was larger in monologue but unchanged in reading. Cepstral peak prominence and Voice-Related Quality of Life scores were significantly higher (improved) after therapy. Conclusion These data contribute to evidence of the effectiveness of this program for hypokinetic dysarthria secondary to idiopathic PD and thus inform clinical practice in the selection among treatment options.

Cepstral Peak Prominence Values for Clinical Voice Evaluation

Purpose The goal of this study was to employ frequently used analysis methods and tasks to identify values for cepstral peak prominence (CPP) that can aid clinical voice evaluation. Experiment 1 identified CPP values to distinguish speakers with and without voice disorders. Experiment 2 was an initial attempt to estimate auditory-perceptual ratings of overall dysphonia severity using CPP values. Method CPP was computed using the Analysis of Dysphonia in Speech and Voice (ADSV) program and Praat. Experiment 1 included recordings from 295 patients with medically diagnosed voice disorders and 50 vocally healthy control speakers. Speakers produced sustained /a/ vowels and the English language Rainbow Passage. CPP cutoff values that best distinguished patient and control speakers were identified. Experiment 2 analyzed recordings from 32 English speakers with varying dysphonia severity and provided preliminary validation of the Experiment 1 cutoffs. Speakers sustained the /a/ vowel and read four sentences from the Consensus Auditory-Perceptual Evaluation of Voice protocol. Trained listeners provided auditory-perceptual ratings of overall dysphonia for the recordings, which were estimated using CPP values in a linear regression model whose performance was evaluated using the coefficient of determination (r ²). Results Experiment 1 identified CPP cutoff values of 11.46 dB (ADSV) and 14.45 dB (Praat) for the sustained /a/ vowels and 6.11 dB (ADSV) and 9.33 dB (Praat) for the Rainbow Passage. CPP values below those thresholds indicated the presence of a voice disorder with up to 94.5% accuracy. In Experiment 2, CPP values estimated ratings of overall dysphonia with r ² values up to .74. Conclusions The CPP cutoff values identified in Experiment 1 provide normative reference points for clinical voice evaluation based on sustained /a/ vowels and the Rainbow Passage. Experiment 2 provides an initial predictive framework that can be used to relate CPP values to the auditory perception of overall dysphonia severity based on sustained /a/ vowels and Consensus Auditory-Perceptual Evaluation of Voice sentences.

Multiparameter Voice Assessment in Dysphonics: Correlation Between Objective and Perceptual Parameters

BACKGROUND

Perceptual assessment and objective measures of voice provide a quantifiable tool for determining the degree of glottal closure, thus helping to distinguish dysphonic voices from normal voices. The correlation between the perceptual and objective parameters of voice in dysphonic can enable the voice pathologist to be more effective in differentiating the normal voices from dysphonic voices. However, only a few studies have investigated the correlation between these measures.

OBJECTIVE

To document the differences in the perceptual and objective parameters of voice in participants with dysphonia and normal controls and to investigate the correlation between the perceptual and objective parameters of voice among participants with dysphonia.

STUDY DESIGN

This investigation deployed standard group comparison and a retrospective study.

METHODS

Two groups of participants were included in the study. Participants in group 1 were diagnosed as having a voice disorder secondary to organic pathologies and group 2 participants had a clinically normal voice. Phonation samples of all the participants were collected and perceptual analysis was carried out using the GRBAS rating scale. As part of the objective measures, acoustic and cepstral measures were extracted from the phonation samples.

RESULTS

The analysis of the results revealed significant differences in perceptual ratings between the normal (control) and dysphonic groups. The mean values of all the objective measures of voice presented significant differences between participants of both groups. The perceptual ratings of grade, breathiness, and roughness showed better correlations with the cepstral measures than with the time-based acoustic measures.

CONCLUSIONS

Further foraging research on the correlation between perceptual and objective measures of voice in various degrees of dysphonia will improve reliability while discriminating and quantifying hoarse, harsh and breathy voices from modal voices.

Effects of Fundamental Frequency, Vocal Intensity, Sample Duration, and Vowel Context in Cepstral and Spectral Measures of Dysphonic Voices

Purpose Smoothed cepstral peak prominence (CPPS) and harmonics-to-noise ratio (HNR) are acoustic measures related to the periodicity, harmonicity, and noise components of an acoustic signal. To date, there is little evidence about the advantages of CPPS over HNR in voice diagnostics. Recent studies indicate that voice fundamental frequency (F0) and intensity (sound pressure level [SPL]), sample duration (DUR), vowel context (speech vs. sustained phonation), and syllable stress (SS) may influence CPPS and HNR results. The scope of this work was to investigate the effects of voice F0 and SPL, DUR, SS, and token on CPPS and HNR in dysphonic voices. Method In this retrospective study, 27 Brazilian Portuguese speakers with voice disorders were investigated. Recordings of sustained vowels (SVs) /a:/ and manually extracted vowels (EVs) /a/ from Consensus Auditory-Perceptual Evaluation of Voice sentences were acoustically analyzed with the Praat program. Results There was a highly significant effect of F0, SPL, and DUR on both CPPS and HNR (p < .001), whereas SS and vowel context significantly affected CPPS only (p < .05). Higher SPL, F0, and lower DUR were related to higher CPPS and HNR. SVs moderately-to-highly correlated with EVs for CPPS, whereas HNR had few and moderate correlations. In addition, CPPS and HNR highly correlated in SVs and seven EVs (p < .05). Conclusion Speaking prosodic variations of F0, SPL, and DUR influenced both CPPS and HNR measures and led to acoustic differences between sustained and excised vowels, especially in CPPS. Vowel context, prosodic factors, and token type should be controlled for in clinical acoustic voice assessment.

Cepstral Analysis of Voice in Young Adults

The fundamental frequency and harmonic organization of voice can be quantified using cepstral measure. The two commonly studied cepstral measures are Cepstral Peak Prominence (CPP) and smoothened Cepstral peak prominence (sCPP). CPP is determined by measuring the amplitude difference from the highest peak of the cepstrum to the corresponding regression line, drawn directly below the cepstral peaks and when a smoothening factor is applied, sCPP is obtained. Cepstral analysis has been reported to be a reliable and valid measure for voice evaluation even for signals with high level of aperiodicity, which the time based measures fails to evaluate. Thus, the present study aimed to investigate the reference values for CPP and sCPP in young adults with normal voice in the age range of 20-40 years. Hundred adults in the age range of 20-40 years with equal number of males and females were considered and the task includes to phonate vowels /a/, /i/ and /u/ for five seconds each and to read "300 word Kannada reading passage" (Savithri & Jayaram, 2005) and the Bengaluru passage. The cepstral analysis was done using speech tool software (version 1.65). The data was subjected to statistical analysis using SPSS (version 21). The present study provides the reference values for CPP and sCPP across various stimuli.

Assessment of Tongue Position and Laryngeal Height in Two Professional Voice Populations

Purpose To advance our current knowledge of singer physiology by using ultrasonography in combination with acoustic measures to compare physiological differences between musical theater (MT) and opera (OP) singers under controlled phonation conditions. Primary objectives addressed in this study were (a) to determine if differences in hyolaryngeal and vocal fold contact dynamics occur between two professional voice populations (MT and OP) during singing tasks and (b) to determine if differences occur between MT and OP singers in oral configuration and associated acoustic resonance during singing tasks. Method Twenty-one singers (10 MT and 11 OP) were included. All participants were currently enrolled in a music program. Experimental procedures consisted of sustained phonation on the vowels /i/ and /ɑ/ during both a low-pitch task and a high-pitch task. Measures of hyolaryngeal elevation, tongue height, and tongue advancement were assessed using ultrasonography. Vocal fold contact dynamics were measured using electroglottography. Simultaneous acoustic recordings were obtained during all ultrasonography procedures for analysis of the first two formant frequencies. Results Significant oral configuration differences, reflected by measures of tongue height and tongue advancement, were seen between groups. Measures of acoustic resonance also showed significant differences between groups during specific tasks. Both singer groups significantly raised their hyoid position when singing high-pitched vowels, but hyoid elevation was not statistically different between groups. Likewise, vocal fold contact dynamics did not significantly differentiate the two singer groups. Conclusions These findings suggest that, under controlled phonation conditions, MT singers alter their oral configuration and achieve differing resultant formants as compared with OP singers. Because singers are at a high risk of developing a voice disorder, understanding how these two groups of singers adjust their vocal tract configuration during their specific singing genre may help to identify risky vocal behavior and provide a basis for prevention of voice disorders.

Fundamental Frequency and Intensity Effects on Cepstral Measures in Vowels from Connected Speech of Speakers with Voice Disorders

OBJECTIVE

Cepstral peak prominence (CPP) and smoothed CPP (CPPS) have been described as reliable parameters to detect overall dysphonia in standardized connected speech samples. Recent studies indicate that vocal intensity (sound pressure level, SPL) and fundamental frequency (f_o) changes may influence cepstral measurement results in healthy speakers. The main aim of the present work was to investigate the effects of prosody related SPL and f_o variations on cepstral measures in speech of adults with voice disorders.

STUDY DESIGN

Retrospective cross-sectional study.

METHODS

Recordings of CAPE-V sentences from 27 voice disordered Brazilian Portuguese speakers (19 women, eight men) with a mean age of 45 years (SD = 13) were investigated. Five /a/ vowels were manually extracted from stressed syllables in different positions. Voice f_o (Hz), SPL (dBA), CPP (dB), and CPPS (dB) were computed using PRAAT. Statistical analysis included Linear Mixed Models with ANCOVA and Bonferroni post hoc tests.

RESULTS

Voice SPL as single factor and combined with f_o had a highly significant effect (P ≤ 0.001), while f_o alone had no significant impact on both CPP and CPPS (P ≥ 0.77). Voice f_o, SPL, CPP, and CPPS of the first vowel were all significantly lower than of the last vowel (P ≤ 0.03).

CONCLUSION

In vowel samples from connected speech of adults with voice disorders, we observed better CPP and CPPS in higher voice SPL alone and combined with higher f_o. Further, the vowel position influenced the present results. A larger clinical study should confirm how prosody related SPL and f_o and vowel position effects could be controlled for in connected speech samples.

Comparison of Cepstral Analysis Based on Voiced-Segment Extraction and Voice Tasks for Discriminating Dysphonic and Normophonic Korean Speakers

OBJECTIVES

This study investigated whether there are differences in the discriminatory power of cepstral analysis according to the voiced-segment extraction method and voice tasks used for identifying dysphonic and normophonic Korean individuals.

MATERIALS AND METHODS

A total of 2,863 subjects (2,595 subjects with and 268 subjects without dysphonia) were included in this study. The 3-second sustained vowel (SV) /a/ and one sentence of "Sanchaek" were edited and analyzed using Praat scripts. Cepstral analyses (cepstral peak prominence [CPP], smoothed cepstral peak prominence [CPPS], and low/high spectral ratio [LHRatio]) were performed using three voice tasks, namely, SV, continuous speech (CS), and extracted continuous speech (EXT) samples. Additionally, auditory-perceptual (A-P) assessments were performed by three speech language pathologists.

RESULTS

Significant differences were found between dysphonic and normophonic voice groups for all cepstral parameters, except the LHRatio_EXT. Cepstral measurements of both SV and CS were highly correlated with A-P ratings. Furthermore, the diagnostic predictive power of CPP and CPPS for CS using the area under the receiver operating characteristic curve (AUC) was >0.919, the positive likelihood ratio (LR+) was ≥6.85, and the negative likelihood ratio (LR-) was ≤0.23. Additionally, for EXT, the AUC was >0.816, LR+ was 3.10, and LR- was ≤0.33.

CONCLUSION

Both CS and EXT can predict dysphonia relatively well (r > 0.816). EXT showed lower predictability than the original sample (CS) analysis. Subsequent studies should implement voiced-segment extraction methods using various algorithms.

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.

Spectral/Cepstral Analyses of Phonation in Parkinson's Disease before and after Voice Treatment: A Preliminary Study

PURPOSE

This article examines cepstral/spectral analyses of sustained /α/ vowels produced by speakers with hypokinetic dysarthria secondary to idiopathic Parkinson's disease (PD) before and after Lee Silverman Voice Treatment (LSVT®LOUD) and the relationship of these measures with overall voice intensity.

METHODOLOGY

Nine speakers with PD were examined in a pre-/post-treatment design, with multiple daily audio recordings before and after treatment. Sustained vowels were analyzed for cepstral peak prominence (CPP), CPP standard deviation (CPP SD), low/high spectral ratio (L/H SR), and Cepstral/Spectral Index of Dysphonia (CSID) using the KAYPENTAX computer software.

RESULTS

CPP and CPP SD increased significantly and CSID decreased significantly from pre- to post-treatment recordings, with strong effect sizes. Increased CPP indicates increased dominance of harmonics in the spectrum following LSVT. After restricting the frequency cutoff to the region just above the first formant and second formant and below the third formant, L/H SR was observed to decrease significantly following treatment. Correlation analyses demonstrated that CPP was more strongly associated with CSID before treatment than after.

CONCLUSION

In addition to increased vocal intensity following LSVT, speakers with PD exhibited both improved harmonic structure and voice quality as reflected by cepstral/spectral analysis, indicating that there was improved harmonic structure and reduced dysphonia following treatment.