Effects of practice with and without knowledge of results on jitter and shimmer levels in normally speaking women

Preliminary Findings of Vocal Fold Vibratory Characteristics of Singers Analyzed by Laryngeal High-Speed Videoendoscopy

OBJECTIVES

This study investigates the vocal fold vibratory dynamics of singers, which are postulated to differ from those of normal speakers due to the singers' regular vocal training. The measurement of vocal fold vibration involved the utilization of laryngeal high-speed videoendoscopy (LHSV) and subsequent LHSV-based analysis. The focus of the present study is to characterize and compare the LHSV-based measures derived from the glottal area waveform (GAW), namely fundamental frequency (F0GAW), glottal perturbation (jitterGAW and shimmerGAW), open quotient (OQGAW), and Nyquist plots, between singers and normal speakers across genders.

METHODS

Participants comprised 13 singers from a local cultural and heritage academy and 56 normal speakers from a local university, all were evaluated to have normal voices. Each participant underwent LHSV procedures to capture images of vocal fold vibration, which were subsequently analyzed to generate the LHSV-based measures.

RESULTS

Male singers exhibited lower F0GAW, jitterGAW, shimmerGAW, and OQGAW than female singers. When compared to normal speakers, male singers demonstrated higher F0GAW, and lower jitterGAW and shimmerGAW. No difference in OQGAW was found between male singers and normal speakers. Female singers exhibited lower jitterGAW compared to normal speakers, but no differences were observed in shimmerGAW and OQGAW. The results of Nyquist plots indicated no gender-related associations between types of rim width and among singers. However, for rim pattern, male singers were associated with a higher percentage of clustered rim, suggesting more regular vocal fold vibration, compared to female singers and normal male speakers.

CONCLUSIONS

Singers, particularly male singers, demonstrate distinct and potentially superior vocal fold vibrations compared to normal speakers, likely attributed to their regular vocal training, resulting in refined vocal fold configurations even during speaking. Despite the limited sample of singers, the study offers valuable insights into the vocal fold vibratory behaviors in singers analyzed using LHSV.

Resonant Voice: Perceptual and Acoustic Analysis After an Intensive Lessac Kinesensic Training Workshop

OBJECTIVE

To investigate whether actors' and actresses' voices post an Intensive Lessac Kinesensic Training Workshop - ILKTW can be perceptually identified as more resonant, and to assess if the Acoustic Voice Quality Index (AVQI), the Acoustic Breathing Index (ABI), and their acoustic measures are able to indicate the classified voices as more resonant.

METHODS

Eight vocally healthy English first-language actors and actresses, participants of the same ILKTW, were asked to sustain the vowel /a/ and to read a piece of the Rainbow Passage, pre and postworkshop, at a self-selected habitual frequency and intensity. The readings were divided into initial and final parts, both with 34 syllables, and combined with the vowel /a/ (3s). The pre and postworkshop recordings (pairs of the initial and final parts followed by the /a/ vowel) of each participant were randomly presented to a voice expert who rated the samples as more resonant or similar. The same samples were analyzed using the AVQI and ABI scripts.

RESULTS

87,5% of the initial parts and 100% of the final in postworkshop were rated by the voice expert as more resonant. Tilt was higher for the postworkshop initial parts (P = 0.036), but a correlation with the perceptual rating wasn't found. HNR was higher (P = 0.018) and jitter was lower (P = 0.017) for the postworkshop final parts. The statistical analysis comparing the perceptive and acoustic data for the final samples couldn't be applied.

CONCLUSION

It seems that the ILKTW has a positive impact on the development of a resonant voice and that the perceptual auditory rating was more effective to describe resonant voices than the AVQI, ABI, and its acoustic measures.

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.

Concatenation of the Moving Window Technique for Auditory-Perceptual Analysis of Voice Quality

PURPOSE

The purpose of this study is to develop a program to concatenate acoustic vowel segments that were selected with the moving window technique, a previously developed technique used to segment and select the least perturbed segment from a sustained vowel segment. The concatenated acoustic segments were compared with the nonconcatenated, short, individual acoustic segments for their ability to differentiate normal and pathological voices. The concatenation process sometimes created a clicking noise or beat, which was also analyzed to determine any confounding effects.

METHOD

A program was developed to concatenate the moving window segments. Listeners with no previous rating experience were trained and, then, rated 20 normal and 20 pathological voice segments, both concatenated (2 s) and short (0.2 s) for a total of 80 segments. Listeners evaluated these segments on both the Grade, Roughness, Breathiness, Asthenia, and Strain scale (GRBAS; 8 listeners) and the Consensus Auditory-Perceptual Evaluation of Voice (Kempster, Gerratt, Abbott, Barkmeier-Kraemer, & Hillman, 2009) scale (7 listeners). The sensitivity and specificity of these ratings were analyzed using a receiver-operating characteristic curve. To evaluate if there were increases in particular criteria due to the beat, differences between beat and nonbeat ratings were compared using a 2-tailed analysis of variance.

RESULTS

Concatenated segments had a higher sensitivity and specificity for distinguishing pathological and normal voices than short segments. Compared with nonbeat segments, the beat had statistically similar increases for all criteria across Consensus Auditory-Perceptual Evaluation of Voice and GRBAS scales, except pitch and loudness.

CONCLUSIONS

The concatenated moving window method showed improved sensitivity and specificity for detecting voice disorders using auditory-perceptual analysis, compared with the short moving window segment. It is a helpful tool for perceptual analytic protocols, allowing for voice evaluation using standardized and automated voice-segmenting procedures.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.7100951.

Measuring vocal motor skill with a virtual voice-controlled slingshot

Successful voice training (e.g., singing lessons) and vocal rehabilitation (e.g., therapy for a voice disorder) involve learning complex, vocal behaviors. However, there are no metrics describing how humans learn new vocal skills or predicting how long the improved behavior will persist post-therapy. To develop measures capable of describing and predicting vocal motor learning, a theory-based paradigm from limb motor control inspired the development of a virtual task where subjects throw projectiles at a target via modifications in vocal pitch and loudness. Ten subjects with healthy voices practiced this complex vocal task for five days. The many-to-one mapping between the execution variables pitch and loudness and resulting target error was evaluated using an analysis that quantified distributional properties of variability: Tolerance, noise, covariation costs (TNC costs). Lag-1 autocorrelation (AC1) and detrended-fluctuation-analysis scaling index (SCI) analyzed temporal aspects of variability. Vocal data replicated limb-based findings: TNC costs were positively correlated with error; AC1 and SCI were modulated in relation to the task's solution manifold. The data suggests that vocal and limb motor learning are similar in how the learner navigates the solution space. Future work calls for investigating the game's potential to improve voice disorder diagnosis and treatment.

Ambulatory Voice Biofeedback: Relative Frequency and Summary Feedback Effects on Performance and Retention of Reduced Vocal Intensity in the Daily Lives of Participants With Normal Voices

Purpose

Ambulatory voice biofeedback has the potential to significantly improve voice therapy effectiveness by targeting carryover of desired behaviors outside the therapy session (i.e., retention). This study applies motor learning concepts (reduced frequency and delayed, summary feedback) that demonstrate increased retention to ambulatory voice monitoring for training nurses to talk softer during work hours.

Method

Forty-eight nurses with normal voices wore the Voice Health Monitor (Mehta, Zañartu, Feng, Cheyne, & Hillman, 2012) for 6 days: 3 baseline days, 1 biofeedback day, 1 short-term retention day, and 1 long-term retention day. Participants were block-randomized into 3 different biofeedback groups: 100%, 25%, and Summary. Performance was measured in terms of compliance time below a participant-specific vocal intensity threshold.

Results

All participants exhibited a significant increase in compliance time (Cohen's d = 4.5) during biofeedback days compared with baseline days. The Summary feedback group exhibited statistically smaller performance reduction during both short-term (d = 1.14) and long-term (d = 1.04) retention days compared with the 100% feedback group.

Conclusions

These findings suggest that modifications in feedback frequency and timing affect retention of a modified vocal behavior in daily life. Future work calls for studying the potential beneficial impact of ambulatory voice biofeedback in participants with behaviorally based voice disorders.

Integration of Motor Learning Principles Into Real-Time Ambulatory Voice Biofeedback and Example Implementation Via a Clinical Case Study With Vocal Fold Nodules

PURPOSE

Ambulatory voice biofeedback (AVB) has the potential to significantly improve voice therapy effectiveness by targeting one of the most challenging aspects of rehabilitation: carryover of desired behaviors outside of the therapy session. Although initial evidence indicates that AVB can alter vocal behavior in daily life, retention of the new behavior after biofeedback has not been demonstrated. Motor learning studies repeatedly have shown retention-related benefits when reducing feedback frequency or providing summary statistics. Therefore, novel AVB settings that are based on these concepts are developed and implemented.

METHOD

The underlying theoretical framework and resultant implementation of innovative AVB settings on a smartphone-based voice monitor are described. A clinical case study demonstrates the functionality of the new relative frequency feedback capabilities.

RESULTS

With new technical capabilities, 2 aspects of feedback are directly modifiable for AVB: relative frequency and summary feedback. Although reduced-frequency AVB was associated with improved carryover of a therapeutic vocal behavior (i.e., reduced vocal intensity) in a patient post-excision of vocal fold nodules, causation cannot be assumed.

CONCLUSIONS

Timing and frequency of AVB schedules can be manipulated to empirically assess generalization of motor learning principles to vocal behavior modification and test the clinical effectiveness of AVB with various feedback schedules.

The Effect of Voice Ambulatory Biofeedback on the Daily Performance and Retention of a Modified Vocal Motor Behavior in Participants With Normal Voices

PURPOSE

Ambulatory biofeedback has potential to improve carryover of newly established vocal motor behaviors into daily life outside of the clinic and warrants systematic research that is lacking in the literature. This proof-of-concept study was designed to establish an empirical basis for future work in this area by formally assessing whether ambulatory biofeedback reduces daily vocal intensity (performance) and the extent to which this change remains after biofeedback removal (retention).

METHOD

Six participants with normal voices wore the KayPENTAX Ambulatory Phonation Monitor for 3 baseline days followed by 4 days with biofeedback provided on odd days.

RESULTS

Compared to baseline days, participants exhibited a statistically significant decrease in mean vocal intensity (4.4 dB) and an increase in compliance (16.8 percentage points) when biofeedback was provided above a participant-specific intensity threshold. After biofeedback removal, mean vocal intensity and compliance reverted back to baseline levels.

CONCLUSIONS

These findings suggest that although current ambulatory biofeedback approaches have potential to modify a vocal motor behavior, the modified behavior may not be retained after biofeedback removal. Future work calls for the testing of more innovative ambulatory biofeedback approaches on the basis of motor control and learning theories to improve retention of a desired vocal motor behavior.

The Effect of Moving Window on Acoustic Analysis

OBJECTIVE

To investigate the effects of the moving window method on acoustic measures and discrimination ability between normal and disordered voices.

METHODS

Fifty-three normal voices and 50 disordered voices were recruited. Three selection methods, the moving window method, the mid-vowel method, and the whole vowel method, were applied to each raw audio signal to determine the most stable segment of each signal. Acoustic parameters such as percent jitter, percent shimmer, signal-to-noise ratio (SNR), cepstral peak prominence (CPP), and correlation dimension (D2) were calculated. The Wilcoxon test was used to compare the stability of these segments across different methods. An artificial neural network was used for estimating how well disordered voices were discriminated from normal ones.

RESULTS

Segments selected using the moving window method were more stable than those selected using the other two methods, meaning lower perturbation and nonlinear dynamic measurements as well as higher SNR and CPP values. The discrimination accuracy rate for the moving window method was 91.90 ± 8.73%, whereas the mid-vowel method and the whole vowel method were 72.34 ± 12.94% and 70.34 ± 5.24%, respectively.

CONCLUSION

The moving window method is capable of providing a more stable audio segment and can discriminate disordered voices from normal ones more effectively.

Voice parameters and videonasolaryngoscopy in children with vocal nodules: a longitudinal study, before and after voice therapy

BACKGROUND

Vocal Nodules (VN) are a functional voice disorder associated with voice misuse and abuse in children. There are few reports addressing vocal parameters in children with VN, especially after a period of vocal rehabilitation.

OBJECTIVE

The purpose of this study is to describe measurements of vocal parameters including Fundamental Frequency (FF), Shimmer (S), and Jitter (J), videonasolaryngoscopy examination and clinical perceptual assessment, before and after voice therapy in children with VN. Voice therapy was provided using visual support through Speech-Viewer software.

MATERIALS AND METHODS

Twenty patients with VN were studied. An acoustical analysis of voice was performed and compared with data from subjects from a control group matched by age and gender. Also, clinical perceptual assessment of voice and videonasolaryngoscopy were performed to all patients with VN. After a period of voice therapy, provided with visual support using Speech Viewer-III (SV-III-IBM) software, new acoustical analyses, perceptual assessments and videonasolaryngoscopies were performed.

RESULTS

Before the onset of voice therapy, there was a significant difference (p<0.05) in mean FF, S and J, between the patients with VN and subjects from the control group. After the voice therapy period, a significant improvement (p<0.05) was found in all acoustic voice parameters. Moreover, perceptual voice analysis demonstrated improvement in all cases. Finally, videonasolaryngoscopy demonstrated that vocal nodules were no longer discernible on the vocal folds in any of the cases.

CONCLUSIONS

SV-III software seems to be a safe and reliable method for providing voice therapy in children with VN. Acoustic voice parameters, perceptual data and videonasolaryngoscopy were significantly improved after the speech therapy period was completed.

Effects of immediate feedback on learning auditory perceptual voice quality evaluation

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

The effect of segment selection on acoustic analysis

OBJECTIVE/HYPOTHESIS

Acoustic analysis is a commonly used method for quantitatively measuring vocal fold function. Voice signals are analyzed by selecting a waveform segment and using various algorithms to arrive at parameters such as jitter, shimmer, and signal-to-noise ratio (SNR). Accurate and reliable methods for selecting a representative vowel segment have not been established.

STUDY DESIGN

Prospective repeated-measure experiment.

METHODS

We applied a moving window method by isolating consecutive, overlapping segments of the raw voice signal from onset through offset. Ten normal voice signals were analyzed using acoustic measures calculated from the moving window. The location and value of minimum perturbation/maximum SNR was compared across individuals. The moving window method was compared with data from the whole vowel excluding onset and offset, the mid-vowel, and the visually selected steadiest portion of the voice signal.

RESULTS

Results showed that the steadiest portion of the waveforms, as defined by minimum perturbation and maximum SNR values, was not consistent across individuals. Perturbation and nonlinear dynamic values differed significantly based on what segment of the waveform was used. Other commonly used segment selection methods resulted in significantly higher perturbation values and significantly lower SNR values than those determined by the moving window method (P<0.001).

CONCLUSIONS

The selection of a sample for acoustic analysis can introduce significant inconsistencies into the analysis procedure. The moving window technique may provide more accurate and reliable acoustic measures by objectively identifying the steadiest segment of the voice sample.

Objective methods of sample selection in acoustic analysis of voice

OBJECTIVES

In acoustic voice analysis, the fact that reproducible methods of sample selection have not been defined impedes research study generalizability and clinical assessment of treatment efficacy. Because perturbation results differ along a single signal, this study sought to establish objective methods of sample selection by use of a moving window to determine the most stable regions of phonation.

METHODS

Voice signals obtained from 21 patients affected by laryngeal conditions associated with Parkinson's disease were analyzed to study jitter, shimmer, signal-to-noise ratio, and correlation dimension parameters when various sample selection procedures were used. Objectively selected voice samples were chosen based upon 5%, 10%, and 20% variance from a signal's minimum perturbation value. The stability of these samples, defined by the standard deviations of the acoustic measurements, was compared to the stability of unselected samples and subjectively selected samples.

RESULTS

A significant decrease in standard deviation values of acoustic parameters was found in comparing the objectively selected samples (particularly those selected with 5% and 10% variance) to the subjectively selected and unselected samples.

CONCLUSIONS

These results suggest that the development of an objective sample selection method may have significant effects on the stability and reliability of acoustic voice measurements.

Voice loudness and gender effects on jitter and shimmer in healthy adults

PURPOSE

The aim of this study was to investigate voice loudness and gender effects on jitter and shimmer in healthy young adults because previous descriptions have been inconsistent.

METHOD

Fifty-seven healthy adults (28 women, 29 men) aged 20-40 years were included in this cross-sectional single-cohort study. Three phonations of /a/ at soft, medium, and loud individual loudness were recorded and analyzed using PRAAT software (P. Boersma & D. Weeninkk, 2006). Voice loudness and gender effects on measured sound pressure level, fundamental frequency, jitter, and shimmer were assessed through the use of descriptive and inferential (analysis of variance) statistics.

RESULTS

Jitter and shimmer significantly increased with decreasing voice loudness, especially in phonations below 75 dB and 80 dB. In soft and medium phonation, men were generally louder and showed significantly less shimmer. However, men had higher jitter measures when phonating softly. Gender differences in jitter and shimmer at medium loudness may be mainly linked to different habitual voice loudness levels.

CONCLUSION

This pragmatic study shows significant voice loudness and gender effects on perturbation. In clinical assessment, requesting phonations above 80 dB at comparable loudness between genders would enhance measurement reliability. However, voice loudness and gender effects in other age groups, in disordered voices, or when a minimal loudness is requested should be further investigated.

Voice Parameters in Children With Down Syndrome

Down syndrome (DS) is the most frequent chromosomal disorder. Commonly, individuals with DS have difficulties with speech and show an unusual quality in the voice. Their phenotypic characteristics include general hypotonia and maxillary hypoplasia with relative macroglossia, and these contribute to particular acoustic alterations. Subjective perceptual and acoustic assessments of the voice (Praat-4.1 software) were performed in 66 children with DS, 36 boys and 30 girls, aged 3 to 8 years. These data were compared with those of an age-matched group of children from the general population. Perceptual evaluations showed significant differences in the group of children with DS. The voice of children with DS presented a lower fundamental frequency (F(0)) with elevated dispersion. The conjunction of frequencies for formants (F(1) and F(2)) revealed a decreased distinction between the vowels, reflecting the loss of articulatory processing. The DS vocalic anatomical functional ratio represents the main distinctive parameter between the two groups studied, and it may be useful in conducting assessments.

The Effect of Speaking Context on Elicitation of Habitual Pitch

The purpose of this study was to investigate if there was an effect of speaking context on the elicitation of habitual pitch [speaking fundamental frequency (SFF)]. Six simulated speaking contexts were created (speaking during a voice evaluation, speaking in public, speaking to a peer, speaking to a superior, speaking to a subordinate, and speaking to a parent or spouse), and the SFF for 30 adult women with normal voice was compared across these contexts. A one-way analysis of variance (ANOVA) revealed a statistically significant (P < 0.001) effect of simulated speaking context on SFF, with post hoc analyses indicating a statistically significant difference in SFF while "speaking to a superior" (P < 0.001) and "speaking to a subordinate" (P < 0.001). Possible reasons for an effect of speaking context are discussed. Also, the implications of the use of varied speaking contexts when eliciting SFF are discussed, as is the possibility of an effect of speaking context on the elicitation of other clinically useful voice parameters.

The Effect of Speaking Sample Duration on Determination of Habitual Pitch

The purpose of this study was to investigate if there was an effect of duration of speaking on determination of habitual pitch. Five speaking periods commonly used to elicit habitual pitch in clinical voice evaluations were compared (1, 5, 15, 30, and 60 seconds). Thirty female speakers with normal voices participated. Results of a within-subject univariate F-test revealed a statistically significant (p < 0.001) difference in habitual pitch among the speaking periods. Habitual pitch for the 1-second and 60-second speaking periods were found to be statistically significantly (p < 0.05) different than all remaining speaking periods, and the habitual pitch for the 30-second speaking period was found to be statistically significantly (p < 0.05) different than 60-second speaking period. Implications for the use of various speaking durations when determining habitual pitch are discussed, as is the possibility of a speaking duration effect on determination of other pitch-related voice parameters.

The effect of task on determination of habitual pitch

The purpose of this study was to investigate if there was an effect of task on determination of habitual pitch, or speaking fundamental frequency (SFF). Seven tasks commonly used to elicit habitual pitch in clinical voice evaluations were compared. Three groups of normal subjects (N = 36) were examined (adult males, adult females, and male and female prepubescent children). For the adult male (n = 12) and pediatric (n = 12) subjects, no significant effect of task was found. For the adult female (n = 12) subjects, a statistically significant (P < .001) effect of task was found. All tasks were found to have high (>0.90) test-retest reliability for all subjects. Implications of the use of one task for determination of habitual pitch are discussed, as is the possibility of a task effect on determination of other voice parameters.

The role of knowledge of results in performance and learning of a voice motor task

The relationship between the provision of Knowledge of Results and the performance and learning of a voice motor task was examined. Thirty adult subjects, randomly assigned to a 100%, 50%, or No Knowledge of Results group, practiced a novel vowel nasalization task. Measures of accuracy and variability obtained during the practice session indicated influence of knowledge of results schedule on the transient effects of motor performance. Deviations from the nasalance target during the retention phase, 5 minutes later, and during a transfer phase, 24 hours later, indicated influence of knowledge of results schedule on the permanent effects of motor learning. Collective results revealed that an increase in relative frequency of knowledge of results led to a decrease in motor performance and learning of a vowel nasalization task: Both accuracy and variability were degraded as knowledge of results increased, with those subjects in the 100% group exhibiting the poorest scores.

The effects of time constraints on phonatory stability in normally speaking adult women

Forty normally speaking women sustained /a/ five times in two conditions, untimed and timed. In the untimed condition, phonation began whenever the subject felt ready. The timed task required subjects to begin phonation as quickly as possible after the examiner's signal. Conditions were counterbalanced across subjects. Jitter and shimmer values were obtained on a Kay Elemetrics Computerized Speech Lab (Pine Brook, NJ). Three distinct patterns of change emerged for jitter and shimmer from the untimed to the timed condition, reflecting either decreases, increases, or no change in values. These changes in jitter and shimmer values across conditions are related to a reaction time model of "bias toward accuracy."