Relationship of Cepstral Peak Prominence-Smoothed and Long-Term Average Spectrum with Auditory–Perceptual Analysis

Water Resistance Therapy in Individuals with Parkinson's Disease: A Session-by-Session Analysis of the Vocal Quality

OBJECTIVES

Verify session-by-session effects of the water resistance therapy (WRT) on the vocal quality of individuals with Parkinson's disease (PD).

METHODS

This is a retrospective analytical study. Then, the samples were acquired from a database composed of 10 men aged between 50 and 90 years old diagnosed with PD. The participants underwent WRT with a resonance tube; then, they were guided to perform the following phonatory tasks: comfortable pitch and loudness, high pitch, low pitch, ascending and descending glissandos, and sentence uttering. Furthermore, tube depth ranged from 2 cm to 9 cm. Finally, WRT was implemented twice per week, totaling eight sessions, each lasting 45 minutes. Participants were assessed before and after each therapy session. Hence, the data were assessed with spectrographic analysis, vocal intensity, cepstral peak prominence-smoothed, alpha ratio, L1-L0, oscillatory frequency, and auditory-perceptual assessment of overall degree, roughness, breathiness, and instability. One-way repeated measures analysis of variance and Friedman tests were applied (P < 0.05). Furthermore, Holm-Sidak and Tukey tests were used as posthoc tests.

RESULTS

After the sixth session, the spectrographic analysis revealed that the tracing color intensity of medium frequencies darkened, whereas a better result could be observed after the eighth session. Regarding vocal intensity, the improvement could be observed from the third session. Additionally, L1-L0 followed the same results. The overall degree auditory-perceptual assessment revealed the best results only after the second, third, and fourth sessions; however, after the eighth session, the instability increased.

CONCLUSIONS

WRT allowed better results from the third session, with some improvements in the sixth session. However, the instability increased after the eighth session; thus, it is important to review the phonatory tasks and session numbers to avoid an overload in the phonatory system.

Cepstral and Perceptual Investigations of Voice in Speech and Language Pathologists with Vocal Fatigue

Vocal fatigue is known as a hyperfunctional voice disorder that can lead to other conditions, such as muscle tension dysphonia (MTD). Speech and language pathologists (SLPs) are professional voice users who may suffer from vocal fatigue due to heavy vocal demands. This study aimed at investigating the cepstral and perceptual dimensions of voice and their correlation in the SLPs with vocal fatigue. Twenty-six SLPs and senior speech therapy students (mean age = 27.11 ± 6.8 yrs), including men (n = 5) and women (n = 21), participated in this descriptive cross-sectional study. They had vocal fatigue according to the Vocal Fatigue Index (VFI). In acoustic assessment, cepstral analysis (CPP and CPPS) was performed using Praat software. The Persian version of Consensus Auditory Perceptual Evaluation of Voice (CAPE-V) was used to evaluate the overall severity of dysphonia. The correlation between these two evaluations was also investigated using IBM SPSS Statistics software version 23. Results revealed that the mean CPPS (13.716 ± 2.084) was lower than the cutoff point. Perceptual findings indicated that the mean overall severity (10.557 ± 11.210) fell in the normal variability of voice quality (NVVQ) range. In addition, cepstral and perceptual evaluations had no significant correlation (P > 0/05). The findings showed that auditory-perceptual evaluation considered the gold standard method of voice evaluation, cannot solely identify vocal fatigue. However, cepstral measures can help provide a more objective profile of vocal function in SLPs with vocal fatigue. Therefore, both of these evaluations are recommended for voice assessment of vocal fatigue.

Acoustic measurements of CPPS and AVQI pre and post speech therapy

PURPOSE

To compare the acoustic measurements of Cepstral Peak Prominence-Smoothed (CPPS) and Acoustic Voice Quality Index (AVQI) at pre- and post-voice therapy times.

METHODS

This is a before and after intervention study, with retrospective data collection. Twenty-two subjects with a mean age of 49.9 years participated in the study. The vocal therapy occurred between the years 2016 to 2019 in a teaching clinic, and the subjects had vocal samples collected before and after the therapeutic processes. CPPS and AVQI data extractions were performed during pre- and post-therapy. In order to characterize the sample, auditory-perceptual evaluation (APE) regarding the overall degree of vocal deviation at pre- and post-therapy moments was performed. The data were analyzed statistically.

RESULTS

The APE data indicated a decrease in the median values of overall vocal deviation degree at the post-therapy stage for both the vowel (p=0.00) and number (p=0.00) samples. The average CPPS for the vowel was 14.53 pre-therapy and 16.37 post-therapy (p=0.01); for the number emission, it was 8.22 pre-therapy and 9.06 post-therapy (p=0.02), there was a difference in the CPPS of the vowel and numbers indicating vocal improvement at post-therapy. The average AVQI was 2.27 pre-therapy and 1.54 post-therapy (p=0.05). There was an improvement in the AVQI results, with borderline p-value.

CONCLUSION

Vocal therapy produced changes in the general degree of vocal deviation, as well as in CPPS and AVQI measurements, and the results at the post-therapy moment are similar to those of vocally healthy individuals.

Acoustic measurements of CPPS and AVQI pre and post speech therapy

PURPOSE

To compare the acoustic measurements of Cepstral Peak Prominence-Smoothed (CPPS) and Acoustic Voice Quality Index (AVQI) at pre- and post-voice therapy times.

METHODS

This is a before and after intervention study, with retrospective data collection. Twenty-two subjects with a mean age of 49.9 years participated in the study. The vocal therapy occurred between the years 2016 to 2019 in a teaching clinic, and the subjects had vocal samples collected before and after the therapeutic processes. CPPS and AVQI data extractions were performed during pre- and post-therapy. In order to characterize the sample, auditory-perceptual evaluation (APE) regarding the overall degree of vocal deviation at pre- and post-therapy moments was performed. The data were analyzed statistically.

RESULTS

The APE data indicated a decrease in the median values of overall vocal deviation degree at the post-therapy stage for both the vowel (p=0.00) and number (p=0.00) samples. The average CPPS for the vowel was 14.53 pre-therapy and 16.37 post-therapy (p=0.01); for the number emission, it was 8.22 pre-therapy and 9.06 post-therapy (p=0.02), there was a difference in the CPPS of the vowel and numbers indicating vocal improvement at post-therapy. The average AVQI was 2.27 pre-therapy and 1.54 post-therapy (p=0.05). There was an improvement in the AVQI results, with borderline p-value.

CONCLUSION

Vocal therapy produced changes in the general degree of vocal deviation, as well as in CPPS and AVQI measurements, and the results at the post-therapy moment are similar to those of vocally healthy individuals.

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.

Efficacy of a Semi-Occluded Vocal Tract Exercises-Therapeutic Program in Behavioral Dysphonia: A Randomized and Blinded Clinical Trial

PURPOSE

Semi-occluded vocal tract exercises (SOVTE) may improve the source and filter interaction by changing the acoustic characteristics and the impedance of the vocal tract, both in dysphonic and vocally healthy populations. However, there are a few studies that verify the effects of these exercises in a clinical trial. Thus, this study's purpose was to analyze the effectiveness of the SOVTE-Therapeutic Program (SOVTE-TP) in vocal quality and self-assessment, comparing it with Vocal Function Exercises.

METHOD

Eighteen (eight men; 10 women), ages 18-50, with behavioral dysphonia participated in this randomized and blinded clinical trial. The participants were equally randomized into two groups: Experimental Group and Vocal Function Exercises Group. They were assessed at three moments: before the treatment, after finishing it, and one month after finishing the treatment--follow up. Acoustic measures (ie, fundamental frequency, jitter, shimmer, noise-to-harmonic ratio, cepstral peak-smoothed, alpha ratio, and L1-L0), auditory-perceptual analysis, vocal fatigue index (VFI), self-perceived resonant voice, and vocal handicap index-30 (VHI-30) were measured at all assessment moments. For the two groups, the interventions happened twice per week (four weeks) and lasted 35 minutes. It was applied the repeated-measures ANOVA test (P< 0.05) and Tukey Test.

RESULTS

The acoustic measures and auditory-perceptual had no differences between the groups and moments, respectively, which means that SOVTE-TP did not cause any harm. The auditory-perceptual analysis showed a mild deviation of participants' vocal quality. All groups reduced the VFI and VHI-30 scores in M2 and kept these results at M3 also, the vocal economy sensation increased in M2, decreasing slightly in M3.

CONCLUSION

SOVTE-TP has positive effects regarding self-assessment (VFI, VHI, and resonant voice quality) on patients with mild behavioral dysphonia, and it provides the same effects as VFE.

Bright Voice Quality and Fundamental Frequency Variation in Non-binary Speakers

OBJECTIVES

1) To investigate if vocal variation produced by assigned-female-at-birth (AFAB) non-binary people differed from vocal variation produced by cisgender (cis) participants. Cue values produced by non-binary participants were predicted to differ from those values produced by cisgender participants. 2) To determine if previous subjective assessments of bright voice quality in AFAB non-binary participants were quantifiable, and if so, if non-binary and cisgender participants differed in their voice quality production.

STUDY DESIGN

A quantitative comparative research design.

METHODS

Phonetic and statistical analyses of continuous speech samples produced by AFAB non-binary and cisgender participants. Vocal cues were mean fundamental frequency (F0) and bright voice quality, measured by cepstral peak prominence-smoothed and spectral slope, with speaker gender as the predictor.

RESULTS

At the group level, non-binary participants produced intermediate F0 values - significantly lower than the cis women's and significantly higher than the cis men's. Individually, the majority of non-binary participants produced mean F0 in this intermediate range. Non-binary participants produced significantly less negative spectral slope and higher cepstral peak prominence-smoothed, indicative of a brighter, more resonant voice quality. Individual-level results indicated that vocal training and vocal tract physiology did not fully account for the results found.

CONCLUSION

Participants' agency, particularly their motivation to alter vocal output to avoid being misgendered, has an effect on the AFAB non-binary participants' F0 production and potentially their voice quality. The majority of AFAB non-binary participants uniquely produced the cue combination of intermediate F0 and bright voice quality.

Effects of Resonance Tube Voice Therapy on Parkinson's Disease: Clinical Trial

PURPOSE

To verify the effect of resonance tube voice therapy on the vocal aspects of patients with Parkinson's Disease (PD).

METHOD

Intra-subject comparative controlled clinical trial with a single group assignment. Fourteen individuals with PD (10 men, mean age 66.1 years; four women, mean age 73.75 years) received eight 45-minute sessions of voice therapy, twice a week for 4 weeks. The therapy consisted of semi-occluded vocal tract exercises - phonation method in a resonance tube (glass, 27 cm x 9 mm) in water. Tube depth in water ranged from 2 cm to 9 cm, as the difficulty in carrying out the exercises increased (usual pitch, high pitch, low pitch, ascending/descending glissandos), followed by sentence production. The assessments were made three times: at baseline (Time0), after 30 days without intervention (Time1), and 1 day after eight intervention sessions (Time2). The following aspects were assessed: vocal intensity; acoustic parameters (Smoothed Cepstral Peak Prominence - CPPs, alpha ratio, and L1-L0 difference); auditory-perceptual analysis of the overall degree of vocal quality deviation; voice symptoms (Voice Symptom Scale protocol - VoiSS) and voice-related quality of life (Voice-Related Quality of Life Protocol - V-RQOL). The results were compared at the three times of assessment Time0/Time1/Time2 using one-way repeated measures ANOVA test and Tukey test (5% significance).

RESULTS

intervention significantly increased: vocal intensity, L1-L0 value of vowel /a/ and counting, CPP value in counting, and decreased: the overall degree of vocal quality deviation in 78% of participants, the total score of VoiSS protocol, the limitation, and emotional subscales. In addition, the intervention increased the score of all the domains of V-RQOL protocol - physical, socio-emotional, and total.

CONCLUSION

Resonance tube phonation in voice therapy was effective in increasing vocal intensity and long-term acoustic parameters, the improved overall degree of vocal quality, reducing voice symptoms, and increasing voice-related quality of life in individuals with PD.

Immediate and long-term effects of speech treatment targets and intensive dosage on Parkinson's disease dysphonia and the speech motor network: Randomized controlled trial

This study compared acoustic and neural changes accompanying two treatments matched for intensive dosage but having two different treatment targets (voice or articulation) to dissociate the effects of treatment target and intensive dosage in speech therapies. Nineteen participants with Parkinsonian dysphonia (11 F) were randomized to three groups: intensive treatment targeting voice (voice group, n = 6), targeting articulation (articulation group, n = 7), or an untreated group (no treatment, n = 6). The severity of dysphonia was assessed by the smoothed cepstral peak prominence (CPPS) and neuronal changes were evaluated by cerebral blood flow (CBF) recorded at baseline, posttreatment, and 7-month follow-up. Only the voice treatment resulted in significant posttreatment improvement in CPPS, which was maintained at 7 months. Following voice treatment, increased activity in left premotor and bilateral auditory cortices was observed at posttreatment, and in the left motor and auditory cortices at 7-month follow-up. Articulation treatment resulted in increased activity in bilateral premotor and left insular cortices that were sustained at a 7-month follow-up. Activation in the auditory cortices and a significant correlation between the CPPS and CBF in motor and auditory cortices was observed only in the voice group. The intensive dosage resulted in long-lasting behavioral and neural effects as the no-treatment group showed a progressive decrease in activity in areas of the speech motor network out to a 7-month follow-up. These results indicate that dysphonia and the speech motor network can be differentially modified by treatment targets, while intensive dosage contributes to long-lasting effects of speech treatments.

Effects of Laryngeal Vibratory Asymmetry and Neuromuscular Compensation on Voice Quality

INTRODUCTION

Vibratory asymmetry and neuromuscular compensation are often seen in laryngeal neuromuscular pathology. However, the ramifications of these findings on voice quality are unclear. This study investigated the effects of varying levels of vibratory asymmetry and neuromuscular compensation on cepstral peak prominence (CPP), an analog of voice quality.

STUDY DESIGN

In vivo canine phonation model.

METHODS

Varying degrees of vocal fold vibratory asymmetry were achieved by stimulating one recurrent laryngeal nerve (RLN) over 11 levels from threshold to maximal muscle activation. For each of these levels, phonation was induced at systematically varied combinations of neuromuscular compensation: three levels each of contralateral RLN stimulation (80%, 90%, and 100% of maximal), superior laryngeal nerve (SLN) activation (0%, 50%, and 100% of maximal), and airflow levels (500, 700, and 900 mL/s). Vocal fold symmetry was determined by assessing the opening phase of the vibratory cycle in high-speed video recordings. Voice quality was estimated acoustically by calculating CPP for each voice sample.

RESULTS

Eight hundred twenty-two phonatory conditions with varying degrees of vibratory asymmetry were evaluated. CPP was highest at vibratory symmetry. Increasing levels of asymmetry resulted in significant decreases in CPP. CPP increased significantly with increasing contralateral RLN activation. CPP was significantly higher at 50% SLN activation than 0% or 100% SLN activation.

CONCLUSION

Voice quality, as approximated by CPP, is best at vibratory symmetry and deteriorates with increasing degrees of asymmetry. Voice quality may be improved with neuromuscular compensation by increased adduction of the contralateral vocal fold or increased vocal fold tension at mid-levels of SLN activation.

LEVEL OF EVIDENCE

NA, Basic Science Laryngoscope, 132:130-134, 2022.