Influence of mean sound pressure level on jitter and shimmer measures

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.

Effect of Face Masks on Voice Quality Associated with Young and Older Chinese Adult Speakers

OBJECTIVES

Face masks have become important after the pandemic, but the change in voice when wearing a face mask is still unclear. The study investigated the effect of face masks on the acoustic and perceptual characteristics of voice quality associated with young and older Chinese adults.

METHODS

Voice samples of the sustained vowel /a/ and continuous speech produced by 44 older and 61 young adults with and without an ASTM level-3 surgical face mask were recorded and analyzed. Perceptual and acoustic parameters including mean fundamental frequency (F0) and intensity, perturbation measures (jitter and shimmer), harmonic-to-noise ratio (HNR), smoothed cepstral peak prominence (CPPs), and long-term average spectrum (LTAS) measures were obtained and compared.

RESULTS

When comparing masked to unmasked voices, for both male and female speakers, F0 and intensity showed no significant changes, except for F0 of continuous speech, which increased significantly. Meanwhile, perturbation measures such as jitter and shimmer were reduced, while HNR and CPPs increased. In addition, LTAS measures included low-frequency mean spectral energy (MSE), high-frequency MSE, and spectral tilt (ST), which were different. For perceptual measures, the overall grade of dysphonia, and roughness were reduced, except for the breathiness among older male speakers, while the other vocal qualities were not changed. Between young and older speakers, significant differences in shimmer, CPPs, and perceived breathiness among male speakers, and low-frequency MSE among female speakers were found.

CONCLUSION

Wearing a surgical mask appeared to change the perceived voice quality. This is supported by the change in perturbation and LTAS measures, and HNR and CPPs values. In addition, some differences between young and older adults were observed. Oral Communication effectiveness may be affected when wearing surgical masks due to changes in voice quality. Additionally, clinicians need to exercise hightened caution in evaluating the voice quality of clients when wearing face masks.

Validation of the Acoustic Breathiness Index in Speakers of Finnish Language

Breathiness (perception of turbulence noise in the voice) is one of the major components of hoarseness in dysphonic voices. This study aims to validate a multiparameter analysis tool, the Acoustic Breathiness Index (ABI), for quantification of breathiness in the speaking voice, including both sustained vowels and continuous speech. One hundred and eight speakers with dysphonia (28 M, 80 F, mean age 50, SD 15.4 years) and 87 non-dysphonic controls (18 M, 69 F, mean age 42, SD 14 years) volunteered as participants. They read a standard text and sustained vowel /a:/. Acoustic recordings were made using a head-mounted microphone. Acoustic samples were evaluated perceptually by nine voice experts of different backgrounds (speech therapists, vocologists and laryngologists). Breathiness (B) from the GRBAS scale was rated. Headphones were used in the perceptual analysis. The dysphonic and non-dysphonic speakers differed significantly from each other in the auditory perceptual evaluation of breathiness. A significant difference was also found for ABI, which had a mean value of 2.26 (SD 1.15) for non-dysphonic and 3.07 (SD 1.75) for dysphonic speakers. ABI correlated strongly with B (rs = 0.823, p = 0.01). ABI's power to distinguish the groups was high (88.6%). The highest sensitivity and specificity of ABI (80%) was obtained at threshold value 2.68. ABI is a valid tool for differentiating breathiness in non-dysphonic and dysphonic speakers of Finnish.

High and Wide: An In Silico Investigation of Frequency, Intensity, and Vibrato Effects on Widely Applied Acoustic Voice Perturbation and Noise Measures

OBJECTIVES

This in silico study explored the effects of a wide range of fundamental frequency (fo), source-spectrum tilt (SST), and vibrato extent (VE) on commonly used frequency and amplitude perturbation and noise measures.

METHOD

Using 53 synthesized tones produced in Madde, the effects of stepwise increases in fo, intensity (modeled by decreasing SST), and VE on the PRAAT parameters jitter % (local), relative average perturbation (RAP) %, shimmer % (local), amplitude perturbation quotient 3 (APQ3) %, and harmonics-to-noise ratio (HNR) dB were investigated. A secondary experiment was conducted to determine whether any fo effects on jitter, RAP, shimmer, APQ3, and HNR were stable. A total of 10 sinewaves were synthesized in Sopran from 100 to 1000 Hz using formant frequencies for /a/, /i/, and /u/-like vowels, respectively. All effects were statistically assessed with Kendall's tau-b and partial correlation.

RESULTS

Increasing fo resulted in an overall increase in jitter, RAP, shimmer, and APQ3 values, respectively (P < 0.01). Oscillations of the data across the explored fo range were observed in all measurement outputs. In the Sopran tests, the oscillatory pattern seen in the Madde fo condition remained and showed differences between vowel conditions. Increasing intensity (decreasing SST) led to reduced pitch and amplitude perturbation and HNR (P < 0.05). Increasing VE led to lower HNR and an almost linear increase of all other measures (P < 0.05).

CONCLUSION

These novel data offer a controlled demonstration for the behavior of jitter (local) %, RAP %, shimmer (local) %, APQ3 %, and HNR (dB) when varying fo, SST, and VE in synthesized tones. Since humans will vary in all of these aspects in spoken language and vowel phonation, researchers should take potential resonance-harmonics type effects into account when comparing intersubject or preintervention and postintervention data using these measures.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Does the Acoustic Voice Quality Index (AVQI) Correlate with Perceived Creak and Strain in Normophonic Young Adult Finnish Females?

BACKGROUND

The Acoustic Voice Quality Index (AVQI) is a correlate of dysphonia. It has been found to differentiate between dysphonic and normophonic speakers and to indicate the effects of voice therapy. This study investigates how the AVQI reacts towards creak and strain, which are common in normophonic speakers.

METHODS

The material was obtained from an earlier study on 104 Finnish female university students (mean age 24.3 years, SD 6.3 years) with no known pathology of voice or hearing and a perceptually normal voice (G = 0 in GRBAS), who were recorded while reading aloud a standard text and sustaining the vowel [a:]. Perceptual analysis for the amount of creak and strain was carried out by 2 expert listeners. In this study, the AVQI v03.01 was analyzed and correlated with perceptual evaluations. Samples with low and high amounts of creak and strain were compared with t tests.

RESULTS

On average, the AVQI was below the threshold value of dysphonia in the Finnish population. The AVQI (ρ = 0.35, p = 0.000) and its subparameters, smoothed cepstral peak prominence (CPPS; ρ = -0.35, p = 0.000) and harmonics-to-noise ratio (HNR; ρ = -0.30, p = 0.002) showed low but significant correlations with creak. Strain had low but significant correlations with spectral Slope (ρ = 0.38, p = 0.000) and Tilt (ρ = -0.40, p = 0.009). The AVQI was lower (better) in samples that were evaluated as having a high amount of strain, but the difference was not significant. Only CPPS differentiated significantly between low and high amounts of creak.

CONCLUSION

The AVQI does not seem to differentiate between high and low amounts of creak and strain in normophonic speakers.

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.

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.

Acoustic Voice Quality Index as a Potential Tool for Voice Screening

INTRODUCTION

To diminish the risk of voice disorders in people who are highly dependent on their voices, such as teachers, vocal screening is important already at the beginning of such individuals' professional studies. A reliable, specified screening tool is needed. The Acoustic Voice Quality Index (AVQI) has been found to differentiate normal voices from abnormal voices and to serve as a treatment outcome measure. This study investigated whether AVQI could be a screening tool in combination with auditory- and self-perception of the voice to discriminate normal from slightly poor voices.

TYPE OF STUDY

Experimental.

METHODS

Some 128 female teaching students (mean age 26.39 years, SD 9.80 years) with no diagnosed voice disorders participated in this study. They read aloud a text in Finnish, sustained the vowel /a:/, and filled the Voice Handicap Index (VHI) questionnaire. Voice samples were recorded with an AKG C544L headset microphone, iFocusrite soundcard, and Praat software using a 44100 sample rate and 16-bit amplitude quantization. Five expert voice therapists evaluated the samples to determine the grade of dysphonia (G) using a scale of 0-0.5 (=normal), 0.5-1 (=mild), 1-2 (=moderate), and 2-3 (=severe). Three medial seconds of [a:] and the first 31 syllables of the text were analyzed using AVQI script version 03.01 in Praat (5.3.55). The analysis gives one AVQI score per participant (scale 0-10). The AVQI threshold of normal and disordered voices for Finnish speakers is 1.83; a G_mean = 0.0-0.5 and VHI score <19 were considered normal. Statistical analysis was done using the receiver operating characteristic (ROC) curve, Spearman's correlation coefficient, and the independent samples t test.

RESULTS

According to the AVQI results, the area under the curve (A_ROC) was 0.554, which is fair. The Youden index gave a cutoff value of 0.30 with a sensitivity of 85% and a specificity of 81.1%. There were weak but significant correlations between G_mean and AVQI and two AVQI parameters, smoothed cepstral peak prominence and harmonic-to-noise ratio (r = 0.27; --0.24; -0.20, respectively; |P < 0.05); and between total VHI and AVQI score and cepstral peak prominence (r = 0.21; 0.20, respectively; P < 0.05). Furthermore, the AVQI scores differed significantly between the groups with a VHI total score <19 and ≥19.

CONCLUSIONS

AVQI did not differentiate between voices that had been perceptually judged as normal or slightly abnormal, but a combination of perceptual assessment in the form of AVQI and VHI could better screen slightly deviant voices.

Effect of two isolated vocal facilitating techniques glottal fry and yawn-sigh on the phonation of female speech-language pathology students: A pilot study

OBJECTIVE

The purpose of this study was to determine the effect of two isolated vocal facilitating techniques, glottal fry and yawn-sigh, on the phonation of vocally healthy female speech-language pathology (SLP) students.

STUDY DESIGN

A multigroup pretest-posttest design was used.

METHODS

A group of thirty-six healthy female SLP students with a mean age of 18.1 years were assigned into three groups: a glottal fry group (practicing the facilitating technique glottal fry across 18 weeks, n=12), a yawn-sigh group (practicing the facilitating technique yawn-sigh across 18 weeks, n=12) and a control group (receiving no facilitating techniques, n=12). To compare vocal measures before and after this training period, an identical objective voice assessment protocol (maximum performance task, acoustic analysis, voice range profile and Dysphonia Severity Index) was performed in the three groups. Groups were compared over time using linear mixed models. Within-group effects of time were determined using post hoc pairwise comparisons.

RESULTS

Glottal fry resulted in a significant decrease in lowest and highest intensity. Yawn-sigh resulted in a significant increase in fundamental frequency, a significant decrease in shimmer and noise-to-harmonic ratio, and a significant increase in highest intensity.

CONCLUSIONS

Yawn-sigh may have a positive effect on the phonation of female vocally healthy future SLPs, whereas results are less supportive for using glottal fry in training this population's voice.

The influence of water resistance therapy on vocal fold vibration: a high-speed digital imaging study

PURPOSE

This study investigated the influence of tube phonation into water on vocal fold vibration.

METHOD

Eight participants were analyzed via high-speed digital imaging while phonating into a silicon tube with the free end submerged into water. Two test sequences were studied: (1) phonation pre, during, and post tube submerged 5 cm into water; and (2) phonation into tube submerged 5 cm, 10 cm, and 18 cm into water. Several glottal area parameters were calculated using phonovibrograms.

RESULTS

The results showed individual differences. However, certain trends were possible to identify based on similar results found for the majority of participants. Amplitude-to-length ratio, harmonic-to-noise ratio, and spectral flatness (derived from glottal area) decreased for all tube immersion depths, while glottal closing quotient increased for 10 cm immersion and contact quotient for 18 cm immersion. Closed quotient decreased during phonation into the tube at 5 cm depth, and jitter decreased during and after it.

CONCLUSION

Results suggest that the depth of tube submersion appears to have an effect on phonation. Shallow immersion seems to promote smoother and more stable phonation, while deeper immersion may involve increased respiratory and glottal effort to compensate for the increased supraglottal resistance. This disparity, which is dependent upon the degree of flow resistance, should be considered when choosing treatment exercises for patients with various diagnoses, namely hyperfunctional or hypofunctional dysphonia.

Influence of F0 and Sequence Length of Audio and Electroglottographic Signals on Perturbation Measures for Voice Assessment

OBJECTIVE

Within the functional assessment of voice disorders, an objective analysis of measured parameters from audio, electroglottographic (EGG), or visual signals is desired. In a typical clinical situation, reliable objective analysis is not always possible due to missing standardization and unknown stability of the clinical parameters. The aim of this study was to investigate the robustness/stability of measured clinical parameters of the audio and EGG signals in a typical clinical setting to ensure a reliable objective analysis. In particular, the influence of F0 and of the sequence length on several definitions of jitter and shimmer will be analyzed.

PATIENTS AND METHODS

Seventy-four young healthy women produced a sustained vowel /a/ and an upward triad with abrupt changeovers. Different sequence lengths (100, 150, 500, and 1000 ms) of sustained phonation and triads (100 and 150 ms) were extracted from the audio and EGG signals. In total, six variations of jitter and four variations of shimmer parameters were analyzed.

RESULTS

Jitter%, Jitter11p, and JitterPPQ of the audio signal as well as Jittermean, Shimmer, and Shimmer11p of the EGG signal are unaffected by both sequence length and F0.

CONCLUSIONS

Influence of F0 and sequence length on several perturbation measures of the audio and EGG signals was identified. For an objective clinical voice assessment, unaffected definitions of jitter and shimmer should be preferred and applied to enable comparability between different recordings, examinations, and studies.

Comparison of dysphonia severity index between younger and older carnatic classical singers and nonsingers

OBJECTIVES

The main objective of this study was to compare dysphonia severity index (DSI) and its parameters between Carnatic classical singers and nonsingers. The second objective was to investigate the effect of age on DSI and its parameters in both singers and nonsingers.

STUDY DESIGN

This study included 30 female Carnatic classical singers who were subdivided into two groups based on their age: 15 younger singers and 15 older singers. These 30 singers were compared with 30 age and gender matched nonsingers.

METHODS

From each participant, measures of highest phonational frequency, lowest intensity, jitter, and maximum phonation time were obtained. Using these, DSI values were calculated.

RESULTS

Singers had significantly greater highest phonational frequency, longer maximum phonation time, and higher DSI values. When compared with the younger participants, older participants had significantly reduced highest phonational frequency, maximum phonation time, and DSI values.

CONCLUSIONS

The results of this study suggest that DSI values vary between Carnatic classical singers and nonsingers, and hence separate normative data may need to be established for this group of singers for clinical comparison purposes.

Spatiotemporal analysis of high-speed videolaryngoscopic imaging of organic pathologies in males

PURPOSE

The aim of this study was to identify parameters that would differentiate healthy from pathological organic-based vocal fold vibrations to emphasize clinical usefulness of high-speed imaging.

METHOD

Fifty-five men (M age = 36 years, SD = 20 years) were examined and separated into 4 groups: 1 healthy (26 individuals) and 3 pathological (10 individuals with contact granuloma, 12 with polyps, and 7 with cysts). Vocal fold vibrations were recorded using a high-speed camera during sustained phonation. Twenty objective glottal area waveform and 24 phonovibrogram parameters representing spatiotemporal characteristics were analyzed. Statistical group comparisons were performed to document spatiotemporal changes for organic lesions that cannot be determined visually. To look for specific pattern profiles within organic lesions, the authors performed linear discriminant analysis.

RESULTS

Thirteen parameters showed significant differences between the healthy group and at least 1 pathological group. The differences occurred more in temporal than in spatial parameters. Contact granuloma showed the fewest statistical differences (3 parameters), followed by cysts (9 parameters), and polyps (10 parameters). Linear discriminant analysis achieved accuracy performance of 76% (all groups separated) and 82% (healthy vs. pathological).

CONCLUSION

The results suggest that for males, the differences between healthy voices and organic voice disorders may be more pronounced within temporal characteristics that cannot be visually detected without high-speed imaging.

Speech tasks and interrater reliability in perceptual voice evaluation

OBJECTIVE/HYPOTHESIS

The optimal selection of speech task is essential for more reliable perceptual ratings and a better understanding of the perceptual qualities of pathologic voices. Nevertheless, researchers have rarely explored this issue using the GRBAS scale. This study investigates the effect of speech task selection on interrater reliability during perceptual voice assessment.

STUDY DESIGN

Experimental study.

METHODS

Sixty subjects, 39 dysphonic subjects and 21 normal controls, performed 13 speech tasks including three 5-second sustained vowel sounds (/ɑ/, /i/, and /u/) each at three pitch levels (high, habitual, and low), maximum phonation of the vowel /ɑ/, pitch glide, counting from 1 to 10, and oral reading of the Rainbow Passage. A group of 18 graduate students in speech-language pathology served as perceptual judges and rated the dysphonic severity for the speech samples based on three parameters in the GRBAS scale-Grade, Roughness, and Breathiness. The formalism of the AC1 statistic proposed by Gwet was applied to determine relative reliability between the speech tasks and the raters.

RESULTS

The counting task and sustained vowel /ɑ/ in high, habitual, and low registers exhibited the most reproducibility and consequently the highest reliability statistic.

CONCLUSIONS

The counting task and sustained /ɑ/ phonation are the optimal tasks for perceptual voice judgment in regard to interrater reliability. Future perceptional studies may benefit from this finding to determine the relationship between speech task selection and the validity of any given perceptual rating system in terms of sensitivity and specificity.

Quantitative analysis of organic vocal fold pathologies in females by high-speed endoscopy

OBJECTIVES/HYPOTHESIS

Quantitative analysis of endoscopic high-speed video recordings of vocal fold vibrations has been growing in importance in recent years. The videos have mainly been analyzed using subjective evaluation, but this is examiner dependent, and the results show inadequate interobserver agreement. The aims of this study were therefore to identify appropriate objective parameters for analyzing high-speed recordings to differentiate healthy voice production from organic disorders.

STUDY DESIGN

METHODS

A total of 152 females were examined, divided into 77 healthy and 75 with four different pathological conditions: laryngeal epithelial thickening, Reinke edema, vocal fold polyps, and vocal fold cysts. Vocal fold vibrations were recorded with a high-speed camera (4,000 Hz, 256 × 256 pixels) during sustained phonation. Parameters computed from the glottal area waveform (GAW) and from phonovibrogram (PVG) were analyzed. Multiparametric linear discriminant analysis was performed to classify pathological conditions versus the healthy group.

RESULTS

Twenty of 44 parameters were identified that are capable of distinguishing between the individual types of pathology. PVG parameters showed better performance than GAW parameters. Parameters representing vibrational periodicity via standard deviation showed better performance than absolute parameters. In addition, linear discriminant analysis achieved reliable differentiation between healthy and pathological vocal fold vibrations: 72% for the five-class problem (all groups separately) and 88% for the two-class problem (healthy vs. all pathologies taken as one class).

CONCLUSIONS

The study succeeded in defining objective parameters for analyzing endoscopic high-speed videos and suggesting first parameters for differentiation between healthy dynamics and dynamics of organic pathologies.

Influence of emotional expression, loudness, and gender on the acoustic parameters of vibrato in classical singers

OBJECTIVES

Vibrato is considered one of the most essential characteristics of the classical singing voice. Vibrato can be acoustically described by the rate, extent, onset, and regularity. The aim of this study was to determine the influence of emotional expression on acoustic parameters of vibrato in classically trained singers.

STUDY DESIGN

A prospective cohort study was performed.

METHODS

Thirty healthy classical singers were recruited for this study, 29 singers met inclusion criteria. Inclusion criteria for this study were as follow: 1) no history of vocal pathology in the past year, 2) to have at least 5 years of classical singing training. Each subject was asked to sing the phrase "I Love You," while expressing four different emotions (tenderness, anger, happiness, and sadness) and without emotion (neutral state). The musical tonality of the phrase was adapted to each singer's vocal classification. Subjects were also recorded at three levels of loudness (pianissimo, mezzo forte, and fortissimo), while expressing each emotion. Acoustical analysis was performed during the vowel /o/ of the word "Love" to determine rate of vibrato, the extent of vibrato, and vibrato jitter.

RESULTS

Vibrato parameters did not vary significantly when different emotions were expressed. However, vibrato jitter and extent did vary significantly between different levels of loudness. Significant differences were also noted in both rate and extent of vibrato when compared between sexes.

CONCLUSIONS

Expression of emotions does not affect the acoustic parameters of vibrato, although some parameters are affected by loudness and gender.

[Voice analysis before and after vocal tiredness]

BACKGROUND/AIM

A school teacher's occupation is one of the most vocal demanding professions. Vocal tiredness affects acoustic characteristics of voice, leads to the change in acoustic quality during vocal production. The aim of this study was to examine the influence of vocal tiredness on voice acoustic characteristics of school teachers.

METHODS

The study included 36 school teachers (16 male and 20 female) of 27-58 years of age. Vocal tiredness was evaluated by analyzing acoustic parameters of voice, using computerized laboratory "Kay Elemetrics". The voices were recorded before the first class on the beginning of a working week and after the last class at the end of a working week. Signal, noise and tremor parameters were processed. In their analysis the methods of descriptive statistics, as well as the analytical statistics (Student's t-test for paired samples, chi2 test, Mann Whitney U-test and Pearson's correlation coefficient) were applied.

RESULTS

The obtained results showed statistically significant differences in average values of parameters as a consequence of the vocal tiredness (p < 0.01), while gender, age and being smoker or not, did not have a significant effect on voice acoustic characteristics in this group of examinees (p > 0.05).

CONCLUSION

The results of the study suggest a casual relationship between vocal tiredness and voice quality in vocal professionals.

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.

Acoustic Measures and Self-reports of Vocal Fatigue by Female Teachers

This study investigated the relation of symptoms of vocal fatigue to acoustic variables reflecting type of voice production and the effects of vocal loading. Seventy-nine female primary school teachers volunteered as subjects. Before and after a working day, (1) a 1-minute text reading sample was recorded at habitual loudness and loudly (as in large classroom), (2) a prolonged phonation on [a:] was recorded at habitual speaking pitch and loudness, and (3) a questionnaire about voice quality, ease, or difficulty of phonation and tiredness of throat was completed. The samples were analyzed for average fundamental frequency (F0), sound pressure level (SPL), and phonation type reflecting alpha ratio (SPL [1-5 kHz]-SPL [50 Hz-1 kHz]). The vowel samples were additionally analyzed for perturbation (jitter and shimmer). After a working day, F0, SPL, and alpha ratio were higher, jitter and shimmer values were lower, and more tiredness of throat was reported. The average levels of the acoustic parameters did not correlate with the symptoms. Increase in jitter and mean F0 in loud reading correlated with tiredness of throat. The results seem to suggest that, at least among experienced vocal professionals, voice production type had little relevance from the point of view of vocal fatigue reported. Differences in the acoustic parameters after a vocally loading working day mainly seem to reflect increased muscle activity as a consequence of vocal loading.

Outcome of Resonant Voice Therapy for Female Teachers With Voice Disorders: Perceptual, Physiological, Acoustic, Aerodynamic, and Functional Measurements

Teachers have a high percentage of voice problems. For voice disordered teachers, resonant voice therapy is hypothesized to reduce voice problems. No research has been done on the physiological, acoustic, and aerodynamic effects of resonant voice therapy for school teachers. The purpose of this study is to investigate resonant voice therapy outcome from perceptual, physiological, acoustic, aerodynamic, and functional aspects for female teachers with voice disorders. A prospective study was designed for this research. The research subjects were 24 female teachers in Taipei. All subjects received resonant voice therapy in groups of 4 subjects, 90 minutes per session, and 1 session per week for 8 weeks. The outcome of resonant voice therapy was assessed from auditory perceptual judgment, videostroboscopic examination, acoustic measurements, aerodynamic measurements, and functional measurements before and after therapy. After therapy the severity of roughness, strain, monotone, resonance, hard attack, and glottal fry in auditory perceptual judgments, the severity of vocal fold pathology, mucosal wave, amplitude, and vocal fold closure in videostroboscopic examinations, phonation threshold pressure, and the score of physical scale in the Voice Handicap Index were significantly reduced. The speaking Fo, maximum range of speaking Fo, and maximum range of speaking intensity were significantly increased after therapy. No significant change was found in perturbation and breathiness measurements after therapy. Resonant voice therapy is effective for school teachers and is suggested as one of the therapy approaches in clinics for this population.

Vocal Loading-Related Changes in Male Teachers’ Voices Investigated before and after a Working Day

Vocal loading-related changes have mainly been investigated in female voice users. The present study investigated male teachers' voices before and after a working day. A questionnaire was used to select 22 male teachers as subjects from a larger group. Ten reported suffering often from symptoms of vocal fatigue (MC = multiple complaints group), 12 reported few vocal complaints (FC group). The subjects recorded a text reading sample at habitual loudness and loudly, and sustained vowel [a:] before and after an approximately 6-hour working day. Text samples were analyzed for total sound pressure level (SPL) and SPL at three frequency regions (50-1,000 Hz, 1-2 kHz, 2-5 kHz), fundamental frequency (F0) and alpha ratio [(SPL 1-5 kHz) - SPL (50 Hz-1 kHz)]. Jitter and shimmer were calculated from the vowel. The subjects filled in a questionnaire about vocal sensations. The MC group reported more symptoms of vocal fatigue, and the symptoms increased during the working day. F0 and SPL increased in both groups. Alpha ratio increased in the MC group but remained the same in the FC group. The MC group had higher values of jitter and shimmer. Jitter diminished in the FC group but did not change significantly in the MC group. The differences between the groups reflect either different strategies for coping with vocal loading or different loading-induced changes in the vocal organ.

[Acoustic voice analysis: reliability of a set of multi-dimensional parameters]

A correlational study of the reliability of acoustic voice parameters was made of 148 healthy adults. Acoustic analysis was performed with MDVP-Multi-Dimensional Voice Program implemented in a CSL-Computerized Speech Lab of Kay Elemetrics. A set of 29 voice parameters were obtained from two samples of sustained vowel /a/ recorded from each subject. General results separated by sex are showed and the test-retest reliability in each pair of measures was calculated. Data show a high intra-subject stability of Frequency Fundamental parameters; acceptable stability in parameters of Frequency and Amplitude Perturbation, Noise, Subharmonics and Voice irregularities; and a very low consistency in Tremor parameters. Parameters related with shimmer were more reliable than parameters related with jitter. According to results several conclusions are reported.

Vocal parameters of aerobic instructors with and without voice problems

Aerobic instructors frequently experience vocal fatigue and are at risk for the development of vocal fold pathology. Six female aerobic instructors, three with self-reported voice problems and three without, served as subjects. Measures of vocal function (perturbation and EGG) were obtained before and after a 30-minute exercise session. Results showed that the group with self-reported voice problems had greater amounts of jitter, lower harmonic-to-noise ratios, and less periodicity in sustained vowels overall, but no significant differences in measures of perturbation and EGG were found before and immediately after instruction. Measures of vocal parameters showed that subjects with self-reported voice problems projected with relatively greater vocal intensity and phonated for a greater percentage of time across beginning, middle, and ending periods of aerobic instruction than subjects with no reported voice problems.

On the influence of laryngeal pathologies on acoustic and electroglottographic jitter measures

This study compared acoustic and electroglottographic (EGG) jitter from [a] vowels of 103 dysphonic speakers. The EGG recordings were chosen according to their intensity, signal-to-noise ratio, and percentage of unvoiced intervals, while acoustic signals were selected based on voicing detection and the reliability of jitter extraction. The agreement between jitter measures was expressed numerically as a normalized difference. In 63.1% (65/103) of the cases the differences fell within +/-22.5%. Positive differences above +22.5% were associated with increased acoustic jitter and occurred in 12.6% (13/103) of the speakers. These were, typically, cases of small nodular lesions without problems in the posterior larynx. On the other hand, substantial rises in EGG jitter leading to differences below -22.5% took place in 24.3% (25/103) of the speakers and were related to hyperfunctional voices, creaky-like voices, small laryngeal asymmetries affecting the arytenoids, or small-to-moderate glottal chinks. A clinically relevant outcome of the study was the possibility of detecting gentle laryngeal asymmetries among cases of large unilateral increase in EGG jitter. These asymmetries can be linked with vocal problems that are often overlooked in endoscopic examinations.

Voice Quality Changes Following Phonatory-Respiratory Effort Treatment (LSVT®) Versus Respiratory Effort Treatment for Individuals with Parkinson Disease

Perceptual ratings of hoarseness and breathiness were used to assess the efficacy of two intensive methods for treating dysarthrophonia in individuals with idiopathic Parkinson disease. One method emphasized phonatory-respiratory effort (the Lee Silverman Voice Treatment, LSVT) and the other emphasized respiratory effort alone (RET). Perceptual ratings were performed by two expert listeners based on random order presentation of the patients' pretreatment and posttreatment recordings of the "Rainbow Passage." The listeners were blinded to the patients and their treatment group. Statistically significant pretreatment to posttreatment improvement in hoarseness and breathiness was observed in the LSVT group but not in the RET group. The present findings are consistent with acoustic and physiologic findings reported previously, providing further evidence for the efficacy of the LSVT.

Relationship between subjective voice complaints and acoustic parameters in female teachers' voices

The aim of the study was to identify the acoustic correlates of female teachers' subjective voice complaints by recording their voices in their working environment. The subjects made recordings during lessons (N = 10) and breaks (N = 11). The subjects were divided into 2 groups: those with few voice complaints (FC group) and those with many voice complaints (MC group). The speech sample made in the breaks was maximally sustained /a/, from which fundamental frequency (F0), jitter, and shimmer were analyzed. The classroom samples were analyzed for F0, sound pressure level (SPL), and F0 time (the active vibration time of the vocal folds). Additionally, an index for assessing voice loading is presented. The results revealed a tendency of the MC group to have higher F0 and lower SPL and perturbation values than the FC group. The index values correlated moderately with the subjective vocal complaints.

Intentional changes in sound pressure level and rate: their impact on measures of respiration, phonation, and articulation

The purpose of the study was to compare the effects of changing sound pressure level (SPL) and rate on respiratory, phonatory, and articulatory behavior during sentence production. Ten subjects, 5 men and 5 women, repeated the sentence, "I sell a sapapple again," under 5 SPL and 5 rate conditions. From a multi-channel recording, measures were made of lung volume (LV), SPL, fundamental frequency (F0), semitone standard deviation (STSD), and upper and lower lip displacements and peak velocities. Loud speech led to increases in LV initiation, LV termination, F0, STSD, and articulatory displacements and peak velocities for both lips. Token-to-token variability in these articulatory measures generally decreased as SPL increased, whereas rate increases were associated with increased lip movement variability. LV excursion decreased as rate increased. F0 for the men and STSD for both genders increased with rate. Lower lip displacements became smaller for faster speech. The interspeaker differences in velocity change as a function of rate contrasted with the more consistent velocity performance across speakers for changes in SPL. Because SPL and rate change are targeted in therapy for dysarthria, the present data suggest directions for future research with disordered speakers.

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."

Performance effects on the voices of 10 choral tenors: acoustic and perceptual findings

Trained choral tenors performed a series of vocal tasks before and after a "live" performance. Acoustic (perturbation, harmonic-to-noise ratio, pitch and amplitude ranges) and perceptual analyses (auditory and proprioceptive/kinesthetic) were undertaken to detect changes from pre- to postperformance. Individuality of response to the performance was revealed, with the majority of subjects showing vocal deterioration after performance. The most sensitive vocal tasks were the comfortably pitched notes, high soft notes, and the bottom notes in scale singing. The most sensitive acoustic measure in detecting change from pre- to postperformance was harmonic-to-noise ratio. In contrast to the demonstrated acoustic changes, no significant differences in perceptual ratings were evident after the performance. Perceptual ratings did not reflect the acoustic analysis results. The present study highlights the need to establish further normative data for the singing voice and to consider individual differences in vocal characteristics in future studies of the singing voice.