Glottal Closure in Women with No Voice Complaints or Laryngeal Disorders

Evaluation of Pediatric Posterior Glottic Diastasis Using Dynamic Voice Computed Tomography

OBJECTIVES

Posterior glottic diastasis (PGD) is an underappreciated etiology of dysphonia in patients with prior airway reconstruction or prolonged intubation. In endoscopic posterior cricoid reduction (ePCR), cricoid is removed to minimize the posterior glottic gap. Dynamic voice computed tomography (DVCT) permits visualization of the posterior glottis, estimating the amount of cricoid to be removed. Posterior glottic gaps in patients undergoing ePCR were compared to non-dysphonic patients to describe pediatric PGD and establish surgical parameters for ePCR.

METHODS

DVCTs performed in non-dysphonic patients and dysphonic patients undergoing ePCR from 2014 to 2023 were reviewed. EPCR operative reports were queried. Pre- and postoperative Pediatric Voice Handicap Index (pVHI) and Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) scores and aerodynamic measures were reviewed.

RESULTS

Seventeen pediatric patients who underwent ePCR and 19 non-dysphonic patients were included. Posterior glottic gaps were significantly larger in the dysphonic group (median 2.4 mm [IQR: 2.0, 2.8] vs. 1.3 mm [IQR: 1.1, 1.7], p < 0.001). Mean width of the cricoid removed was 1.6 mm (SD 0.4 mm). Mean (SD) pre- and postoperative pVHI scores were 55.5 (19.9) and 34.6 (16.0; p < 0.001). Mean (SD) pre- and postoperative CAPE-V scores were 52.7 (15.4) and 36.5 (20.4; p < 0.001), respectively.

CONCLUSIONS

Children in this cohort tolerated an average 1.3 mm posterior glottic gap without dysphonia. Dysphonic patients with PGD had a median 2.4 mm gap and underwent cricoid reduction by 1.6 mm. All ePCR patients demonstrated improvement in dysphonia. Results seek to optimize the management of pediatric PGD and present a safe and effective amount of cricoid to remove during ePCR.

LEVEL OF EVIDENCE

4 Laryngoscope, 2024.

Effect of Nebulization on Laryngeal Parameters: Analysis Using High-Speed Digital Videolaryngoscopy

INTRODUCTION

Superficial laryngeal hydration, obtained through nebulization, is related to the moisture level on the epithelial surfaces of the vocal folds, modifying their biomechanical and aerodynamic properties. Through high-speed videolaryngoscopy it is possible to obtain objective data for laryngeal analysis after nebulization and a better understanding of this phenomenon OBJECTIVE: To verify the effects of nebulization with saline solution on laryngeal parameters of digital videokymography obtained by high-speed videolaryngoscopy examination in women and men with and without laryngeal alterations METHOD: This is a clinical, comparative intra-subject study. Fifty-nine adults were selected, with and without laryngeal alterations, 30 females and 29 males. Digital videokymographs in the anterior, middle and posterior thirds of the vocal folds of the participants were analyzed before and after nebulization with 0.9% saline solution.

RESULTS

Women without laryngeal alterations showed more parameters changes after nebulization, in which there was a decrease in maximum and medium opening, amplitude of opening of the left and right vocal fold in the anterior glottal third, and an increase of the percentage of closure of the vocal folds. These results indicate a minor extent of lateral excursion of the vocal folds during phonation. In women with laryngeal alterations, the parameters that changed after nebulization were the increased frequency of opening of the left and right vocal folds in the topography of the posterior third. In men, nebulization did not change the variables studied, except for the amplitude of the right vocal fold in men with laryngeal alterations, in the analysis of the posterior glottic third.

CONCLUSION

The results suggest that surface hydration modifies laryngeal dynamics differently between genders. After nebulization with saline solution, women without laryngeal alterations showed a decrease in the lateralization of the vocal folds during phonation, suggesting a better phonatory efficiency.

A Chaotic Approach to Glottal Gap Voice

OBJECTIVE

Airway glottic insufficiency, or glottal gap, may lead to a breathy voice quality. It is hypothesized that a glottal gap may be a source of nonlinearity in speech production. This study aims to gain a chaotic and acoustic profile of glottal gap voice provided by phonation of excised larynges subjected to the insertion of a metal shim in the posterior glottis.

STUDY DESIGN

Nonrandomized quasi-experimental study.

METHODS

Posterior glottal gap varied from 0 to 3.5 mm in 0.5 mm intervals. Each treatment was investigated independently in a sample population of eight excised canine larynges. Phonation of the larynges for each treatment was recorded and analyzed for the cepstral peak prominence (CPP), harmonics-to-noise ratio (HNR), and correlation dimension.

RESULTS

Kruskal-Wallis rank-sum tests yielded significant differences across shim groups for all parameters. Dunn-Bonferroni post-hoc tests revealed that the control group differed significantly from the 1.5, 2, 2.5, 3, and 3.5 mm groups for all metrics. Moreover, Kendall correlation tests indicated a moderately positive correlation between glottal gap size and correlation dimension, a moderately negative correlation between glottal gap size and CPP and between glottal gap size and the HNR.

CONCLUSIONS

Glottic insufficiency provides a source of nonlinearity in phonation. Nonlinear dynamic analysis provides quantitative insight into glottal gap voice. This study encourages future studies to further evaluate the relationship between glottal gap and correlation dimension.

Automatic Segmentation of Membranous Glottal Gap Area with U-Net-Based Architecture

BACKGROUND

While videostroboscopy is recognized as the most popular approach for investigating vocal fold function, evaluating the numerical values, such as the membranous glottal gap area, remains too time consuming for clinical applications.

METHODS

We used a total of 2507 videostroboscopy images from 137 patients and developed five U-Net-based deep-learning image segmentation models for automatic masking of the membranous glottal gap area. To further validate the models, we used another 410 images from 41 different patients.

RESULTS

During development, all five models exhibited acceptable and similar metrics. While the VGG19 U-Net had a long inference time of 1654 ms, the other four models had more practical inference times, ranging from 16 to 138 ms. During further validation, Efficient U-Net demonstrated the highest intersection over union of 0.8455, the highest Dice coefficient of 0.9163, and the lowest Hausdorff distance of 1.5626. The normalized membranous glottal gap area index was also calculated and validated. Efficient U-Net and VGG19 U-Net exhibited the lowest mean squared errors (3.5476 and 3.3842) and the lowest mean absolute errors (1.8835 and 1.8396).

CONCLUSIONS

Automatic segmentation of the membranous glottal gap area can be achieved through U-net-based architecture. Considering the segmentation quality and speed, Efficient U-Net is a reasonable choice for this task, while the other four models remain valuable competitors. The models' masked area enables possible calculation of the normalized membranous glottal gap area and analysis of the glottal area waveform, revealing promising clinical applications for this model.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:2835-2843, 2024.

Neural network-based estimation of biomechanical vocal fold parameters

Vocal fold (VF) vibrations are the primary source of human phonation. High-speed video (HSV) endoscopy enables the computation of descriptive VF parameters for assessment of physiological properties of laryngeal dynamics, i.e., the vibration of the VFs. However, underlying biomechanical factors responsible for physiological and disordered VF vibrations cannot be accessed. In contrast, physically based numerical VF models reveal insights into the organ's oscillations, which remain inaccessible through endoscopy. To estimate biomechanical properties, previous research has fitted subglottal pressure-driven mass-spring-damper systems, as inverse problem to the HSV-recorded VF trajectories, by global optimization of the numerical model. A neural network trained on the numerical model may be used as a substitute for computationally expensive optimization, yielding a fast evaluating surrogate of the biomechanical inverse problem. This paper proposes a convolutional recurrent neural network (CRNN)-based architecture trained on regression of a physiological-based biomechanical six-mass model (6 MM). To compare with previous research, the underlying biomechanical factor "subglottal pressure" prediction was tested against 288 HSV ex vivo porcine recordings. The contributions of this work are two-fold: first, the presented CRNN with the 6 MM handles multiple trajectories along the VFs, which allows for investigations on local changes in VF characteristics. Second, the network was trained to reproduce further important biomechanical model parameters like VF mass and stiffness on synthetic data. Unlike in a previous work, the network in this study is therefore an entire surrogate of the inverse problem, which allowed for explicit computation of the fitted model using our approach. The presented approach achieves a best-case mean absolute error (MAE) of 133 Pa (13.9%) in subglottal pressure prediction with 76.6% correlation on experimental data and a re-estimated fundamental frequency MAE of 15.9 Hz (9.9%). In-detail training analysis revealed subglottal pressure as the most learnable parameter. With the physiological-based model design and advances in fast parameter prediction, this work is a next step in biomechanical VF model fitting and the estimation of laryngeal kinematics.

Digital Videokymography: Analysis of Glottal Closure in Adults

INTRODUCTION

High-speed videolaryngoscopy and quantitative analysis of laryngeal images are relevant in accurately diagnosing vocal fold closure patterns.

OBJECTIVE

To analyze the parameters of digital videokymography obtained through high-speed videolaryngoscopy in women and men with complete and incomplete glottal closure, and posterior glottal chink.

METHODS

We conducted an observational, analytical, cross-sectional study with data from 65 adults, which we divided into groups according to sex and glottal closure. Digital videokymography parameters were analyzed using an image-processing program. The Anderson-Darling and Mann-Whitney U tests were used to verify sample normality and compare videokymography parameters between groups, respectively. The significance level was set at 5%.

RESULTS

Among 65 laryngeal images, 20 each were from women with complete and incomplete glottal closure, and 20 and 5 were from men with complete and incomplete glottal closure, respectively. Considering the clinical relevance of the evaluated data, groups of 11 women and 4 men with posterior glottal chink were compared with sex-similar groups with complete glottal closure. Digital videokymography showed a lower maximum and mean vocal fold opening in women with incomplete glottal closure, and a lower dominant left vocal fold-opening amplitude and higher dominant frequency of bilateral vocal fold opening in men with incomplete glottal closure. It also showed a lower closed phase percentage in the posterior region for women and men, with higher closed phase percentage in the anterior and middle regions in women. Both groups with posterior glottal chink showed similar results.

CONCLUSION

Incomplete glottal closure may interfere with the results of the digital videokymography parameters, with higher impact on the posterior vocal fold region in males and the middle and anterior vocal fold regions in females.

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSION

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

Comparison between the acoustic fundamental frequency of the voice and the vibration frequency of the vocal folds analyzed by digital kymography

PURPOSE

To compare the frequency of vocal fold opening variation, analyzed by digital kymography, with the fundamental voice frequency obtained by acoustic analysis, in individuals without laryngeal alteration.

METHODS

Observational analytical cross-sectional study. The participants were forty-eight women and 38 men from 18 to 55 years of age. The evaluation was made by voice acoustic analysis, by the habitual emission of the vowel /a/ for 3 seconds, and days of the week, and digital kymography (DKG), by the habitual emission of the vowels /i/ and /ɛ/. The measurements analyzed were acoustic fundamental frequency (f0), extracted by the Computerized Speech Lab (CSL) program, and dominant frequency of the variation of right (R-freq) and left (L-freq) vocal fold opening, obtained through the KIPS image processing program. The mounting of the kymograms consisted in the manual demarcation of the region by vertical lines delimiting width and horizontal lines separating the posterior, middle and anterior thirds of the Rima glottidis. In the statistical analysis, the Anderson-Darling test was used to verify the normality of the sample. The ANOVA and Tukey tests were performed for the comparison of measurements between the groups. For the comparison of age between the groups, the Mann-Whitney test was used.

RESULTS

There are no differences between the values of the frequency measurement analyzed by digital kymography, with the acoustic fundamental frequency, in individuals without laryngeal alteration.

CONCLUSION

The values of the dominant frequency of the vocal folds opening variation, as assessed by digital kymography, and the acoustic fundamental frequency of the voice are similar, allowing comparison between these measurements in the multidimensional evaluation of the voice, in individuals without laryngeal alteration.

Effect of Ligament Fibers on Dynamics of Synthetic, Self-Oscillating Vocal Folds in a Biomimetic Larynx Model

Synthetic silicone larynx models are essential for understanding the biomechanics of physiological and pathological vocal fold vibrations. The aim of this study is to investigate the effects of artificial ligament fibers on vocal fold vibrations in a synthetic larynx model, which is capable of replicating physiological laryngeal functions such as elongation, abduction, and adduction. A multi-layer silicone model with different mechanical properties for the musculus vocalis and the lamina propria consisting of ligament and mucosa was used. Ligament fibers of various diameters and break resistances were cast into the vocal folds and tested at different tension levels. An electromechanical setup was developed to mimic laryngeal physiology. The measurements included high-speed video recordings of vocal fold vibrations, subglottal pressure and acoustic. For the evaluation of the vibration characteristics, all measured values were evaluated and compared with parameters from ex and in vivo studies. The fundamental frequency of the synthetic larynx model was found to be approximately 200-520 Hz depending on integrated fiber types and tension levels. This range of the fundamental frequency corresponds to the reproduction of a female normal and singing voice range. The investigated voice parameters from vocal fold vibration, acoustics, and subglottal pressure were within normal value ranges from ex and in vivo studies. The integration of ligament fibers leads to an increase in the fundamental frequency with increasing airflow, while the tensioning of the ligament fibers remains constant. In addition, a tension increase in the fibers also generates a rise in the fundamental frequency delivering the physiological expectation of the dynamic behavior of vocal folds.

Degree of Breathiness in a Synthesized Voice Signal as it Differentiates Masculine versus Feminine Voices

INTRODUCTION

Most studies determining speakers' perceived gender as binarily female or male are reliant on F0 perception, although other vocal parameters may also contribute to the perception of gender. The current study focused on the impact of breathiness on the perception of speakers' gender as a biological variable (feminine or masculine).

METHODS

n = 31 normal hearing, native English speakers, 18 female, 13 male, mean age 23 (SD = 3.54), were auditorily and visually trained in and then took part in a categorical perception task. A continuum of nine samples of the word "hello", was created in an airway modulation model of speech and voice production. Resting vocal fold length, resting vocal fold thickness, F0, and vocal tract length were fixed. Glottal width at the vocal process, posterior glottal gap, and bronchial pressure were continually modified for all stimuli. Each stimulus was randomly presented 30 times within each of the five blocks (150 presentations in total). Participants rated stimuli as binarily female or male.

RESULTS

Showed a sigmoidal shift in breathiness along the continuum between perceived feminine or masculine voicing. This shift was evident at stimuli four and five, indicating a nonlinear, discrete perception of breathiness among participants. Response times were also significantly slower in these two stimuli, suggesting a categorical perception of breathiness among participants.

CONCLUSION

Breathiness created by the change in glottal width of at least 0.21 cm may influence the perception of a speaker's perceived gender.

Differences in Glottal Closure and Visibility of the Anterior Commissure during Rigid-90°, Rigid-70°, and Flexible Laryngostroboscopy

INTRODUCTION

The conventional rigid-90° and rigid-70° laryngostroboscopy has been so far considered the gold standard in assessing the vibratory behavior of the vocal folds and the glottal closure configuration during phonation. Meanwhile, this rigid laryngostroboscopy is more and more replaced by flexible chip-on-tip systems. The aim of this study was to evaluate the influence of these different endoscopic techniques on glottal closure configuration and on visibility of the complete focal fold length including anterior commissure during phonation.

METHODS

Twenty-one euphonic subjects were enrolled (mean age 34.6 ± 9.5; m = 10, f = 11). They were examined with the three laryngoscopic techniques (conventional rigid-90°, rigid-70°, and flexible chip-on-tip laryngoscopy during low and high voice pitch with soft and loud voice intensity). For evaluating the degree of glottal closure, a modified classification of Södersten et al. was applied and the visibility of the anterior commissure was evaluated. The correlation of the three endoscopic techniques was assessed with Cohen and Fleiss' kappa.

RESULTS

In even low loud phonation, the rigid-90° and rigid-70° endoscopies revealed a complete closure of the glottis in only 47.6% of subjects but with flexible endoscopy in 81%. The complete vocal fold length with anterior commissure was best visible with flexible endoscopy in 90.5% in low-soft and high-soft phonation. The rigid-90° endoscopy showed a slight agreement in comparison with the flexible endoscopy in regard to the types of vocal fold closure with a Cohen's kappa coefficient k = 0.199. The rigid-90° endoscopy showed an almost perfect agreement with k = 0.84 when compared to the rigid-70° endoscopy. The flexible endoscopy compared to the rigid-70° endoscopy showed a fair agreement with k = 0.346.

CONCLUSION

We found mainly corresponding results in both rigid-90° and rigid-70° endoscopic techniques which can be explained by the same transoral approach with the tongue pulled out, whereas the flexible transnasal endoscopy mainly gives a better view on the anterior commissure. The influence of transorally or transnasally guided endoscopic techniques needs to be considered in interpretation of laryngostroboscopic parameters like vocal fold closure and supraglottal hyperactivity.

Collision Pressure and Dissipated Power Dose in a Self-Oscillating Silicone Vocal Fold Model With a Posterior Glottal Opening

PURPOSE

The goal of this study was to experimentally evaluate how compensating for the adverse acoustic effects of a posterior glottal opening (PGO) by increasing subglottal pressure and changing supraglottal compression, as have been associated with vocal hyperfunction, influences the risk of vocal fold (VF) trauma.

METHOD

A self-oscillating synthetic silicone model of the VFs with an airflow bypass that modeled a PGO was investigated in a hemilaryngeal flow facility. The influence of compensatory mechanisms on collision pressure and dissipated collision power was investigated for different PGO areas and supraglottal compression. Compensatory behaviors were mimicked by increasing the subglottal pressure to achieve a target sound pressure level (SPL).

RESULTS

Increasing the subglottal pressure to compensate for decreased SPL due to a PGO produced higher values for both collision pressure and dissipated collision power. Whereas a 10-mm² PGO area produced a 12% increase in the peak collision pressure, the dissipated collision power increased by 122%, mainly due to an increase in the magnitude of the collision velocity. This suggests that the value of peak collision pressure may not fully capture the mechanisms by which phonotrauma occurs. It was also found that an optimal value of supraglottal compression exists that maximizes the radiated SPL, indicating the potential utility of supraglottal compression as a compensatory mechanism.

CONCLUSIONS

Larger PGO areas are expected to increase the risk of phonotrauma due to the concomitant increase in dissipated collision power associated with maintaining SPL. Furthermore, the risk of VF damage may not be fully characterized by only the peak collision pressure.

Economic Burden Associated With Management of Paradoxical Vocal Fold Motion Disorder

OBJECTIVES

Paradoxical vocal fold movement (PVFM) is often misdiagnosed as asthma and tends to have a prolonged time to diagnosis. Study aims were to estimate the time from dyspnea onset to PVFM diagnosis, to estimate associated pre- and postdiagnosis direct and indirect healthcare cost, and to compare the cost of postdiagnosis care among patients who did and did not undergo standard-of-care speech therapy.

METHODS

Patients diagnosed with PVFM were identified retrospectively. Time from dyspnea symptom onset to diagnosis was measured. Direct costs consisting of office visits, procedures, and prescribed pharmaceuticals before and after diagnosis were calculated. Indirect costs associated with lost wages related to healthcare were also estimated. Costs for patients who initiated versus did not initiate speech therapy and who had successful versus unsuccessful therapy were compared.

RESULTS

Among 110 patients, median time from dyspnea onset to PVFM diagnosis was 33 months (interquartile range [IQR] 5-60). Direct and indirect prediagnosis median costs were $8,625 (IQR $1,687-$35,812) and $736 (IQR $421-$1,579) while first year following dyspnea symptom onset median direct and indirect costs were $1,706 (IQR $427-$7,118) and $315 (IQR $131-$631). Median direct and indirect costs of care in the postdiagnosis year were $2,062 (IQR $760-$11,496) and $841 (IQR $631-$1,261). Pharmaceuticals were predominant cost drivers in all time periods. Of those who completed speech therapy, 85% had breathing symptom improvement while incurring significant cost savings compared to those whose symptoms persisted.

CONCLUSION

Costs of care leading to diagnosis of PVFM are substantial. More efficient methods of identifying patients with PVFM are essential to reduce prolonged time to diagnosis and associated costs.

LEVEL OF EVIDENCE

N/A Laryngoscope, 2021.