Glottal Airflow and Glottal Area Waveform Characteristics of Flow Phonation in Untrained Vocally Healthy Adults

Laryngeal and Acoustic Analysis of Chest and Head Registers Extended Across a Three-Octave Range: A Case Study

Voice registers are assumed to be related to different laryngeal adjustments, but objective evidence has been insufficient. While chest register is usually associated with the lower pitch range, and head register with the higher pitch range, here we investigated a professional singer who claimed an ability to produce both these registers at every pitch, throughout her entire singing range. The singer performed separated phonations alternating between the two registers (further called chest-like and head-like) at all pitches from C3 (131 Hz) to C6 (1047 Hz). We monitored the vocal fold vibrations using high-speed video endoscopy and electroglottography. The microphone sound was recorded and used for blind listening tests performed by the three authors (insiders) and by six "naive" participants (outsiders). The outsiders correctly identified the registers in 64% of the cases, and the insiders in 89% of the cases. Objective analysis revealed larger closed quotient and vertical phase differences for the chest-like register within the lower range below G4 (<392 Hz), and also a larger closed quotient at the membranous glottis within the higher range above Bb4 (>466 Hz), but not between Ab4-A4 (415-440 Hz). The normalized amplitude quotient was consistently lower in the chest-like register throughout the entire range. The results indicate that that the singer employed subtle laryngeal control mechanisms for the chest-like and head-like phonations on top of the traditionally recognized low-pitched chest and high-pitched head register phenomena. Across all pitches, the chest-like register was produced with more rapid glottal closure that was usually, but not necessarily, accompanied also by stronger adduction of membranous glottis. These register changes were not always easily perceivable by listeners, however.

Glottal Imaging Study Comparing Vowel Phonation with Semioccluded Vocal Tract Exercises (SOVTEs) Produced Loudly

OBJECTIVES

This study aimed to estimate vocal loading in loud phonation of a vowel and two widely used semiocclusion voice exercises (SOVTEs). Impact stress (IS) was estimated from glottal closing speed, inertial forces from the second derivative of glottal opening and closing.

STUDY DESIGN

Experimental study in vivo.

METHODS

A vocally healthy male sustained the [o:] vowel with habitual loudness and loudly: (1) without a tube, (2) into a silicone "Lax Vox" type tube (35 cm in length, 10 mm in diameter) outer end submerged 10 cm in water, and (3) into a straw (length 12.6 cm, diameter 2.5 mm) the outer end in air. He tried to use equal effort in all loud samples. High-speed video-laryngo-endoscopy was performed with a rigid scope. Oral air pressure (Poral) was registered in a mouthpiece through which the endoscope was inserted into the larynx and to which the tubes were attached air-tightly.

RESULTS

Compared with vowel phonation at habitual loudness, mean of maximal glottal width (max GW) increased by 44.1% for loud tube phonation and decreased by 1.8% for loud straw phonation, and mean absolute value of minimum GW time derivative dmin increased by 57.1% for tube and by 29.5% for straw suggesting faster glottal closing. Compared with loud vowel phonation, max GW increased by 22.6% for loud tube phonation, while it decreased by 16.6% for loud straw phonation. For the tube, dmindecreased by 7.6% and for the straw by 23.8%. Maximal acceleration (ACC) and deceleration (DC) values were larger for the tube and smaller for the straw than the values for both vowel phonations.

CONCLUSIONS

IS, deduced from dmin, increased in loud SOVTEs compared to vowel phonation at a conversational loudness, but remained lower in loud SOVTEs than in loud vowel phonation, particularly with a narrow straw, which also reduced inertial forces, as suggested by the reduced ACC and DC.

Analysis of Voice Changes in Early-Stage Parkinson's Disease with AVQI and ABI: A Follow-up Study

OBJECTIVES

The purpose of this pilot study was to examine voice quality changes in individuals with early-stage Parkinson's disease (PD) utilizing the Acoustic Voice Quality Index (AVQI) and Acoustic Breathiness Index (ABI) over approximately a 1-year period.

STUDY DESIGN

Follow-up study.

METHODS

Baseline and follow-up data were gathered from the PDSTUlong speech corpus. The data for both time points included: speaker background information, sustained vowels, reading samples, and measures of PD severity (Hoehn and Yahr scores and Unified Parkinson's Disease Rating Scale III scores [UPDRS-III]). All speakers (N = 12) were native Finnish speakers. AVQIv03.01 and ABI analysis were completed in VOXplot v2.0.1. Changes in AVQI and ABI scores between baseline and follow-up were examined via causal analysis. Further, AVQI and ABI were analyzed in relation to measures of PD severity.

RESULTS

Baseline mean AVQI score was 1.79 (range 0.14-4.83, SD=1.60), whereas follow-up mean AVQI score was 2.25 (range 0.55-4.53, SD=1.36). Baseline mean ABI score, in turn, was 2.92 (range 1-27 - 5.31, SD=1.57), whereas follow-up mean ABI score was 3.42 (range 1.40-5.40, SD=1.38). A significant difference was found between baseline and follow-up measures for both AVQI (Z = -2.002, P = 0.045) and ABI (Z = -2.197, P = 0.028). A significant difference in smoothed cepstral peak prominence (Z = -2.118, P = 0.034) and harmonics-to-noise ratio (Z = -1.961, P = 0.050) was also found between the two measurement periods. Change in AVQI and ABI were not correlated with the change in measures of PD severity.

CONCLUSION

Over approximately 1-year, a statistical change was observed in AVQI and ABI scores, even in such a small dataset. The specific qualities of breathiness and hoarseness showed the most significant progression. Changes in voice quality were more prominent in ABI analysis.

Clinical and Anatomical Variation During Assessment of Maximum Glottic Angle

INTRODUCTION

Quantitative measurement and analysis of glottic abduction is used to assess laryngeal function and success of interventions; however, the consistency of measurement over time has not been established. This study assesses the consistency of glottic abduction measurements across visits in healthy patients and anatomic factors impacting these measurements.

METHODS

Review of patients with two sequential flexible stroboscopic exams over seven months from 2019-2022. Images of maximal glottic abduction were captured and uploaded into and measured with ImageJ. Cadaver heads were used to assess the impact of visualization angles on glottic measurements with a monofilament inserted into the supraglottis of each cadaver as a point of reference. Comparisons were done with a paired T-test, T-test, or Mann-Whitney U test as appropriate.

RESULTS

Fifty-nine patients and twenty-six cadaveric exams were included. Absolute change in maximum glottic abduction angle (MGAA) was 6.90° (95% CI [5.36°, 8.42°]; p < 0.05). There were no significant differences in change in MGAA by gender or age. Twenty percent of patients had a change of at least 25% in their MGAA between visits. Absolute differences in glottic angle between nasal side for cadaveric measurements was 4.77 ± 4.59° (p < 0.005)-2.22° less than the change in MGAA seen over time (p = 0.185).

CONCLUSION

Maximal glottic abduction angles varied significantly between visits. Factors considered to be contributing to the differences include different viewing windows between examinations due to the position and angulation of the laryngoscope and changes in patient positioning, intra- and inter-rater variations in measurement, and patient effort.

LEVEL OF EVIDENCE

N/a Laryngoscope, 134:2793-2798, 2024.

The Role of EGG in Identifying Prevocalic Glottal Stop

OBJECTIVE

The aim of the study is to investigate the use of incidences and characteristics of Prevocalic Electroglottographic Signal (PVES) derived from electroglottography (EGG) in characterizing glottal stops (GS) in cleft palate speech.

METHODS

Mandarin nonaspirated monosyllabic first-tone words were used for the speech sampling procedure. A total of 1680 utterances (from 83 patients with repaired cleft palates) were divided into three categories based on the results of auditory-perceptual evaluation of recorded speech sounds by three independent reviewers: [Category A (absence of GS agreed by all three reviewers) (n = 1192 tokens), Category B (two out of three reviewers agreed on the presence of a GS) (n = 181 tokens) and Category C (all three reviewers agreed on the presence of a GS) (n = 307 tokens)]. The EGG signals of the 1680 utterances were analyzed using a MATLAB program to automatically mark the instances of PVES (amplitude and time-interval) in the GS utterances.

RESULTS

The result showed that the incidence of EGG PVES presented good positive correlation with auditory-perceptual evaluation (r = 0.703, P＜0.000). Statistical analysis revealed a significant difference in mean PVES amplitude among different groups (P＜0.05). There was a significant distinction in the time interval between groups A and B, as well as in groups A and C (P＜0.05).

CONCLUSIONS

The study suggests PVES can be an objective means of identifying GS in cleft palate speech. It also indicates that proportion of amplitude and time interval of PVES tend to be positively correlate with subjective assessment.

Aerodynamic Parameters in Byzantine Chant Voices: Comparisons Across Pitch and Loudness

OBJECTIVE

This study was designed to assess the impact of phonation frequency and loudness increase on aerodynamic parameters of the singing voice in Byzantine chant (BC).

DESIGN

Aerodynamic measurements in BC were obtained and statistically analyzed.

METHOD

Fifteen experienced BC chanters, all baritones, performed the ascending notes G2, C3, E3, G3, C4, E4, and G4, at normal and high levels of loudness within a mask, while repeating strings of /pi/ syllables. The parameters of airflow (FR), subglottal pressure (Psub), and sound pressure level (SPL) were directly measured, and from them, the glottal flow resistance (Rg) and vocal efficiency (VE) were calculated. All the parameters' values were statistically analyzed.

RESULTS

Statistically significant differences for FR, Psub, and SPL parameters in BC between the two loudness levels, at constant pitch, and for Psub, SPL, Rg, and VE among different pitches, at constant loudness levels were detected. When loudness increases, a) only the mean values of FR, Psub, and SPL, within C3-C4, increase, whereas those of Rg and VE do not show any change, and b) at G2, only the mean Psub increases, while in the upper range E4-G4, both mean SPL and mean VE decrease. When pitch is raised, a) for each level of loudness, within G2-E4 pitch range, the means of Psub, SPL, Rg, and VE increase while this is not the case for FR, and b) in the highest range (E4-G4), average SPL and VE drop while Rg and Psub remain stable. Our findings suggest that: a) most participants increase Psub and SPL without modification of Rg when loudness increases, and b) most participants increase both SPL and Psub while changing Rg with pitch rise. Idiosyncratic differences among the participants were detected in Rg and Psub, because of pitch rise, and, also, in Rg and VE due to loudness increase.

CONCLUSIONS

The results from this study reveal that, within the C3-C4 pitch range: a) there is independent control between the loudness and glottal adduction, and b) Psub is the main tool for increasing both the loudness and SPL. For some exceptions among the participants, either the Rg alteration or other modifications of the vocal system are, possibly, the cause of the loudness increase. The increased mean values of SPL, Rg, and Psub with pitch rise, for most participants, suggest that both glottal adduction and Psub increase together with the SPL and pitch increase. The VE increase within G2-E4 pitches reaches a maximum value at E4. Some exceptions among the participants exist that suggest the possible use of different phonatory strategies when changing either the pitch or the vocal loudness.

Flow-induced oscillations of vocal-fold replicas with tuned extensibility and material properties

Human vocal folds are highly deformable non-linear oscillators. During phonation, they stretch up to 50% under the complex action of laryngeal muscles. Exploring the fluid/structure/acoustic interactions on a human-scale replica to study the role of the laryngeal muscles remains a challenge. For that purpose, we designed a novel in vitro testbed to control vocal-folds pre-phonatory deformation. The testbed was used to study the vibration and the sound production of vocal-fold replicas made of (i) silicone elastomers commonly used in voice research and (ii) a gelatin-based hydrogel we recently optimized to approximate the mechanics of vocal folds during finite strains under tension, compression and shear loadings. The geometrical and mechanical parameters measured during the experiments emphasized the effect of the vocal-fold material and pre-stretch on the vibration patterns and sounds. In particular, increasing the material stiffness increases glottal flow resistance, subglottal pressure required to sustain oscillations and vibratory fundamental frequency. In addition, although the hydrogel vocal folds only oscillate at low frequencies (close to 60 Hz), the subglottal pressure they require for that purpose is realistic (within the range 0.5-2 kPa), as well as their glottal opening and contact during a vibration cycle. The results also evidence the effect of adhesion forces on vibration and sound production.

Laryngeal, Respiratory, and Acoustic Characteristics of Vocal Trillo With Simultaneous High-Speed Videoendoscopy, Inductive Plethysmography, and Acoustic Recordings

OBJECTIVE

This study aimeed to examine the characteristics of formed and unformed trillo, an essential ornament found in 17th-century Italian vocal music, using simultaneous multimodality voice measurements.

PARTICIPANT AND METHODS

A 28-year-old female with 12 years of classical voice training and 7 years of advanced training in historical performance produced formed trillo, unformed trillo, oscillating trill, vibrato, and straight tone on the vowel /i/. Simultaneous high-speed videoendoscopy, inductive plethysmography, and acoustic recordings were conducted to examine the laryngeal motion, respiratory kinematics, and output sound characteristics.

RESULTS

The study findings reveal that trillo in this single participant is not only produced by the periodic adduction/abduction of the vocal fold but also with underlying differences in oscillatory mechanisms and increased glottal flow (use of percent vital capacity) controlled by increased activation of abdominal muscles and/or decreased activation (inspiratory braking) of the diaphragm relative to tidal breathing when compared with straight tone, vibrato, and oscillating trill. The formed trillo differs from the unformed trillo in the oscillatory mechanisms and glottal airflow utilization.

CONCLUSIONS

The physiological mechanism responsible for trillo is more complex than simply adduction and abduction. Future studies with a greater number of participants are needed to evaluate the mechanisms responsible for the formation of and the auditory-perceptual differences between the formed versus unformed trillo.

Examining Therapy Duration in Adults With Voice Disorders

PURPOSE

This study examined the number of voice therapy sessions and the number of weeks in treatment to achieve desired voice outcomes in adults with voice disorders. Factors that may predict therapy duration were examined, as was the percentage of patients returning to the clinic for additional voice therapy after initial discharge.

METHOD

An observational cohort design was utilized. Data from 558 patients were extracted from the University of Wisconsin-Madison Voice and Swallow Outcomes Database. Patients diagnosed with muscle tension dysphonia, vocal fold paralysis, benign vocal fold lesions, laryngospasm/irritable larynx, and presbyphonia were examined. Patient demographics, auditory-perceptual assessments, acoustics, aerodynamics, videostroboscopy ratings, self-reported scales, and medical comorbidities were collected.

RESULTS

Patients required an average of 5.32 (SD = 3.43) sessions of voice therapy before voice outcomes were sufficiently improved for discharge. Average number of sessions ranged from 4.3 for presbyphonia to 6.7 for benign vocal fold lesions. Baseline overall Grade Roughness Breathiness Asthenia and Strain rating (p < .001), Dysphonia Severity Index (p < .001), Voice Handicap Index score (p < .01), age (p = .006), and occupational voice user status (p < .001) significantly predicted the number of therapy sessions required. Overall, 14.5% of patients returned for additional voice therapy following an initial discharge from treatment.

CONCLUSIONS

Findings inform our understanding of how many sessions patients with voice disorders require to achieve desired voice outcomes. Additional research is needed to optimize the efficacy of voice treatment and determine how recurrence of dysphonia might best be prevented.

High-Speed Image Analysis Comparing Loading of Vocal Folds During Coughing and Phonation: A Case Study

PURPOSE

Coughing is related to voice problems, since it involves firm glottal closure, fast glottal opening, and high subglottic pressure and flow rate. In this study, the glottal area variation and movements of laryngeal structures during coughing and phonation are compared.

METHODS

High-speed laryngoscopy recordings were made of a normophonic male participant with a healthy larynx producing a neutral vowel and coughing. Oral air pressure was registered in a mouthpiece, through which an endoscope was inserted into the pharynx. Electroglottography, acoustic, and pressure signals were recorded simultaneously. The glottal width variation at the membranous and cartilaginous parts of the glottis was derived from the high-speed images, and the strong vibration of the false vocal folds was also registered.

RESULTS

In coughing, compared to ordinary vowel phonation in nearly the same sound pressure level (93-94 dB_6cm), the glottal width was 25% larger at the middle of the vocal folds, the maximum glottal opening velocity was 39% higher, and the maximum glottal width declination rate during glottal closing was up to three times higher. The maximum acceleration was 40% higher, and the maximum deceleration was 47% higher. Fundamental frequency f₀ was the highest (ca. 400 Hz) at the beginning of the first phase of a typical coughing process. During the last part of the coughing process, f₀ decreased from ca. 250 Hz to ca. 85 Hz at the phonation offset.

CONCLUSIONS

The remarkable increase in maximum glottal width declination rate implies much higher vocal fold loading in coughing compared to phonation.

High-Speed Videoendoscopic and Acoustic Characteristics of Inspiratory Phonation

PURPOSE

Given the importance of inspiratory phonation for assessment of vocal fold structure, the aim of this investigation was to evaluate and describe the vocal fold vibratory characteristics of inspiratory phonation using high-speed videoendoscopy in healthy volunteers. The study also examined the empirical relationship between cepstral peak prominence (CPP) and glottal area waveform measurements derived from simultaneous high-speed videoendoscopy and audio recordings.

METHOD

Vocally healthy adults (33 women, 28 men) volunteered for this investigation and completed high-speed videoendoscopic assessment of vocal fold function for two trials of an expiratory/inspiratory phonation task at normal pitch and normal loudness. Twelve glottal area waveform measures and acoustic CPP values were extracted for analyses.

RESULTS

Inspiratory phonation resulted in shorter closing time, longer duration of the opening phase, and faster closing phase velocity compared to expiratory phonation. Sex differences were elucidated. CPP changes for inspiratory phonation were predicted by changes in the glottal area index and waveform symmetry index, whereas changes in CPP during expiratory phonation were predicted by changes in asymmetry quotient, glottal area index, and amplitude periodicity.

CONCLUSIONS

Vocal fold vibratory differences were identified for inspiratory phonation when compared to expiratory phonation, the latter of which has been studied more extensively. This investigation provides important basic inspiratory phonation data to better understand laryngeal physiology in vivo and provides a basic model from which to further study inspiratory phonation in a larger population representing a broader age range.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22223812.

Re-Training of Convolutional Neural Networks for Glottis Segmentation in Endoscopic High-Speed Videos

Endoscopic high-speed video (HSV) systems for visualization and assessment of vocal fold dynamics in the larynx are diverse and technically advancing. To consider resulting "concepts shifts" for neural network (NN)-based image processing, re-training of already trained and used NNs is necessary to allow for sufficiently accurate image processing for new recording modalities. We propose and discuss several re-training approaches for convolutional neural networks (CNN) being used for HSV image segmentation. Our baseline CNN was trained on the BAGLS data set (58,750 images). The new BAGLS-RT data set consists of additional 21,050 images from previously unused HSV systems, light sources, and different spatial resolutions. Results showed that increasing data diversity by means of preprocessing already improves the segmentation accuracy (mIoU + 6.35%). Subsequent re-training further increases segmentation performance (mIoU + 2.81%). For re-training, finetuning with dynamic knowledge distillation showed the most promising results. Data variety for training and additional re-training is a helpful tool to boost HSV image segmentation quality. However, when performing re-training, the phenomenon of catastrophic forgetting should be kept in mind, i.e., adaption to new data while forgetting already learned knowledge.

High-Speed Characterization of Vocal Fold Vibrations in Normally Cycling and Postmenopausal Women: Randomized Double-Blind Analyses

Purpose The aim of this study was to examine the influence of menstrual cycle phases (follicular, ovulatory, luteal, and ischemic) and hormone levels (estradiol, testosterone, progesterone, and neuropeptide Y) on vocal fold vibrations in reproductive and postmenopausal women. Method Glottal area waveforms were extracted from high-speed videoendoscopy during sustained phonation, inhalation phonation, and voice onset/offset in the reproductive (n = 15) and postmenopausal (n = 13) groups. Linear mixed-model analysis was conducted to evaluate hormone levels and high-speed videoendoscopy outcome variables between the reproductive and postmenopausal groups. In the reproductive group, simple linear regression and multiple regression were conducted to determine the effects of hormones on the dependent variables. Results Group differences between reproductive and postmenopausal women were identified for stiffness index, oscillatory onset time, and oscillatory offset time. Neuropeptide Y hormone in the ischemic phase significantly predicted changes in the reproductive group for some dependent variables; however, the relationship varied for sustained phonation and inhalation phonation. Conclusion These findings provide preliminary evidence that vocal fold vibrations in the reproductive group are different predominantly in the ischemic phase due to neuropeptide Y changes.