Automated detection of glottic laryngeal carcinoma in laryngoscopic images from a multicentre database using a convolutional neural network.

OBJECTIVE: Little is known about the efficacy of using artificial intelligence (AI) to identify laryngeal carcinoma from images of vocal lesions taken in different hospitals with multiple laryngoscope systems. This multicentre study aimed to establish an AI system and provide a reliable auxiliary tool to screen for laryngeal carcinoma. STUDY DESIGN: Multicentre case-control study. SETTING: Six tertiary care centres. PARTICIPANTS: Laryngoscopy images were collected from 2179 patients with vocal fold lesions. OUTCOME MEASURES: An automatic detection system of laryngeal carcinoma was established and used to distinguish malignant and benign vocal lesions in 2179 laryngoscopy images acquired from 6 hospitals with 5 types of laryngoscopy systems. Pathological examination was the gold standard for identifying malignant and benign vocal lesions. RESULTS: Out of 89 cases in the malignant group, the classifier was able to correctly identify laryngeal carcinoma in 66 patients (74.16%, sensitivity). Out of 640 cases in the benign group, the classifier was able to accurately assess the laryngeal lesion in 503 cases (78.59%, specificity). Furthermore, the region-based convolutional neural network (R-CNN) classifier achieved an overall accuracy of 78.05%, with a 95.63% negative predictive value and a 32.51% positive predictive value for the testing data set. CONCLUSION: This automatic diagnostic system has the potential to assist clinical laryngeal carcinoma diagnosis which may improve and standardise the diagnostic capacity of laryngologists using different laryngoscopes.

Chaos Behavior Analysis of Alaryngeal Voices Including Esophageal and Tracheoesophageal Voices.

HYPOTHESIS/OBJECTIVES: This study's objective was to develop a method to evaluate the chaotic characteristic of alaryngeal speech. The proposed method will be capable of distinguishing between normal and alaryngeal voices, including esophageal (SE) and tracheoesophageal (TE) voices. It has been previously shown that alaryngeal voices exhibit chaotic characteristics due to the aperiodicity of their signals. The proposed method will be applied for future use to quantify both chaos behavior (CB) and the difference between SE and TE voices. STUDY DESIGN: A total of 74 voice recordings including 34 normal and 40 alaryngeal (26 SE and 14 TE) were used in the study. Voice samples were analyzed to distinguish alaryngeal voices from normal voices and to investigate different chaotic characteristics of SE and TE speech. METHODS: A chaotic distribution detection-based method was used to investigate the CB of alaryngeal voices. This CB was used to detect the difference between SE and TE voice types. Quantification of the CB parameter was performed. Statistical analyses were used to compare the results of the CB analysis for both the SE and TE voices. RESULTS: Statistical analysis revealed that CB effectively differentiated between all normal and alaryngeal voice types (p < 0.01). Subsequent multiclass receiver operating characteristic (ROC) analysis demonstrated that CB (area under the curve) possessed the greatest classification accuracy relative to correlation dimension (D2). CONCLUSIONS: The CB metric shows strong promise as an accurate, useful metric for objective differentiation between all normal and alaryngaeal, SE and TE voice types. The CB calculations showed expected results, as SE voices have significantly more CB than TE voices, constituting substantial improvement over previous methods and becoming the first SE and TE classification method. This metric can help clinicians obtain additional acoustic information when monitoring the efficacy of treatment for patients undergoing total laryngectomies.

The integrity and barrier function of porcine vocal fold epithelium: its susceptibility to damage by deoxycholic acid compared with pepsin.

PURPOSE: In this study, we aim to systematically evaluate the damaging role of gastric (pepsin and acid) and duodenal ingredients (bile acids) on vocal fold epithelium in excised porcine larynges. METHODS: Fresh ex vivo porcine larynges were exposed to one of five experimental conditions for 1 h. These conditions will be referred to as alkaline deoxycholic acid, acidic pepsin, acid pH3 only, acid pH5 only, and control, respectively. A Franz diffusing cell was used to evaluate the barrier function of vocal fold epithelium by measuring the permeability to fluorescein isothiocyanate dextran of 4 kDa. Histological changes were observed using transmission electron microscopy. RESULTS: After immersing the fresh porcine larynges in the five solution groups, we found that the vocal fold epithelium in the deoxycholic acid group had more permeability to FD4 than the pepsin group (P < 0.001). Fragmentation and desquamation of dead cell layers were observed in both the pepsin and deoxycholic acid groups, but were more severe in the deoxycholic acid group than the pepsin group. The thickness of the dead epithelial cell layer gradually increased with increasing acid concentration (P < 0.05). Additionally, the thickness of the dead epithelial cell layer in the deoxycholic acid group was significantly higher than that in the pepsin group (P < 0.01). CONCLUSION: Deoxycholic acid in a weakly acidic condition is more likely than pepsin to induce apoptosis in ex vivo porcine vocal fold epithelium, destroy the link proteins between epithelial cells, and affect their integrity and barrier function.

Study of spatiotemporal liquid dynamics in a vibrating vocal fold by using a self-oscillating poroelastic model.

The main purpose of this study is to investigate the spatiotemporal interstitial fluid dynamics in a vibrating vocal fold. A self-oscillating poroelastic model is proposed to study the liquid dynamics in the vibrating vocal folds by treating the vocal fold tissue as a transversally isotropic, fluid-saturated, porous material. Rich spatiotemporal liquid dynamics have been found. Specifically, in the vertical direction, the liquid is transported from the inferior side to the superior side due to the propagation of the mucosal wave. In the longitudinal direction, the liquid accumulates at the anterior-posterior midpoint. However, the contact between the two vocal folds forces the accumulated liquid out laterally in a very short time span. These findings could be helpful for exploring etiology of some laryngeal pathologies, optimizing laryngeal disease treatment, and understanding hemodynamics in the vocal folds.

Wound-healing effects of 635-nm low-level laser therapy on primary human vocal fold epithelial cells: an in vitro study.

Low-level laser therapy (LLLT) has been promoted for its beneficial effects on tissue healing and pain relief for skin and oral applications. However, there is no corresponding literature reporting on vocal fold wound healing. Our purpose was to assess the potential wound-healing effects of LLLT on primary human vocal fold epithelial cells (VFECs). In this study, normal vocal fold tissue was obtained from a 58-year-old male patient who was diagnosed with postcricoid carcinoma without involvement of the vocal folds and underwent total laryngectomy. Primary VFECs were then cultured. Cells were irradiated at a wavelength of 635 nm with fluences of 1, 4, 8, 12, 16, and 20 J/cm2 (50 mW/cm2), which correspond to irradiation times of 20, 80, 160, 240, 320, and 400 s, respectively. Cell viability of VFECs in response to varying doses of LLLT was investigated by the Cell Counting Kit-8 (CCK-8) method. The most effective irradiation dose was selected to evaluate the cell migration capacity by using the scratch wound-healing assay. Real-time polymerase chain reaction (RT-PCR) was used to detect the gene expression of TGF-ß1, TGF-ß3, EGF, IL-6, and IL-10. Irradiation with doses of 8 J/cm2 resulted in 4% increases in cell proliferation differing significantly from the control group (p < 0.05). With subsequent doses at 48 and 72 h after irradiation, the differences between the experimental and the control groups became greater, up to 9.8% (p < 0.001) and 19.5% (p < 0.001), respectively. It also increased cell migration and the expression of some genes, such as EGF, TGF-ß1, TGF-ß3, and IL-10, involved in the tissue healing process. This study concludes that LLLT at the preset parameters was capable of stimulating the proliferation and migration of human vocal fold epithelial cells in culture as well as increase the expression of some genes involved in tissue healing process. Additionally, successive laser treatments at 24 h intervals have an additive beneficial effect on the healing of injured tissues.

Effects of a simulated system of straw phonation on the complete phonatory range of excised canine larynges.

PURPOSE: This study investigated the effects of straw phonation therapy on the aerodynamic and acoustic parameters of the vocal folds at different levels of elongation and subglottal pressure. METHODS: 20 excised canine larynges were used in both experimental (straw phonation therapy simulation) and control conditions. Aerodynamic parameters, including phonation threshold pressure (PTP), phonation instability pressure (PIP), phonation pressure range (PPR), phonation threshold flow (PTF), phonation instability flow (PIF), phonation flow range (PFR), were obtained at different levels of vocal fold elongation (0%, 10%, 20%). Acoustic parameters, including fundamental frequency (F0), jitter, shimmer, signal noise ratio (SNR) were detected at different levels of vocal fold elongation (0%, 10%, 20%) and subglottal pressure (15 cmH2O, 20 cmH2O, 25 cmH2O). RESULTS: Significant decreases in PTP and PTF and significant increases in PIP, PIF, PPR, and PFR occurred in experimental condition at all levels of elongation when compared with control condition. However, no significant changes of acoustic parameters were obtained between conditions at all levels. CONCLUSION: At different levels of vocal fold elongation, straw phonation not only lowered the onset of normal voice, but also elevated the onset of chaotic voice, indicating a better voice economy and voice control. Moreover, the improved phonatory range demonstrated that straw phonation had the potential to prevent voice users who have high voice demand from voice fatigue and vocal damage.

Establishment of a novel and effective reflux laryngitis model in rabbits: a preliminary study.

PURPOSE: To establish a novel and effective reflux model with a modified nasogastric aspiration tube and to investigate the association between different types of nasogastric aspiration tubes and reflux laryngitis, we conducted this study. METHODS: Thirty-eight healthy New Zealand albino rabbits (2.5-3.5 kg) were divided into three groups: control (CTR, n = 6)-non-intubated; normal nasogastric intubation (NNI, n = 16)-intubated with 4#, 6#, 8#, and 10# normal nasogastric aspiration tubes; and modified nasogastric intubation (MNI, n = 16)-intubated with 4#, 6#, 8#, and 10# modified nasogastric aspiration tubes. The laryngoscopy, body weight, and pH values at the esophageal entrance were recorded before and 1, 2, and 4 weeks after intubation. After the final laryngoscopy, the animals in groups with a pH below 4 were sacrificed to obtain histological and gene expression analysis results. RESULTS: The reflux finding score (RFS) after 4 weeks showed that there was a statistically significant difference in the 8# NNI group (7 ± 0.816, P < 0.001), the 8# MNI group (11.5 ± 2.517, P < 0.001) and the 10# MNI (12.75 ± 1.893, P < 0.001) group compared with the control group (1.83 ± 1.602). The pH values of these three groups were lower than 4. However, the weight loss of the rabbits in the 10# NNI and 10# MNI groups was more obvious. Submucous gland hyperplasia and inflammation were significantly increased in the 8# NNI group, 8# MNI group and the 10# MNI group, but in the level of some pro-inflammatory cytokines and COX-2, the MNI group was significantly higher than the NNI group (8# NNI × 8# MNI, P < 0.01; 8# MNI × 10# MNI, P < 0.01). CONCLUSION: This study showed that 8# modified nasogastric intubation (MNI) produces effective reflux laryngitis in the rabbits.

Prolonged phonation impairs the integrity and barrier function of porcine vocal fold epithelium: a preliminary study.

PURPOSE: Voice abuse is known to be a common risk factor of voice disorders and prolonged; high-intensity phonation has been shown to damage the vocal fold epithelium. We aim to evaluate the effects of phonation on the integrity and barrier function of vocal fold epithelium using a porcine laryngeal model. METHODS: Ex vivo porcine larynges were phonated at low intensity or high intensity for 15, 30, or 60 min within 4 h after harvest. Vocal fold epithelium was visualized using transmission electron microscopy (TEM). The barrier function of vocal fold epithelium was evaluated by measuring the permeability to model molecules, fluorescein (376 Da), and fluorescein isothiocyanate (FITC)-dextrans of 4000 and 10,000 Da (FD4, FD10), in a Franz diffusing cell. RESULTS: Cell death and dilated intercellular space after phonation were observed using TEM. Thickness of vocal fold epithelium was significantly reduced after low-intensity phonation for 30 and 60 min and high-intensity phonation for 15, 30, and 60 min. Epithelial permeability to fluorescein was significantly increased after low-intensity phonation for 30 and 60 min, and high-intensity phonation. Permeability to FD4 was significantly increased after high-intensity phonation for 30 and 60 min. Phonation did not alter the permeability to FD10 significantly. CONCLUSION: Long-duration phonation destroys the integrity and barrier function of vocal fold epithelium. These effects likely make vocal folds more vulnerable to other environmental irritants, such as tobacco smoke, reflux components, allergens, and inhaled pollutants. Destroyed barrier function may be an important factor in the pathogenesis of voice lesions related to voice abuse.

Evaluation of an asymmetric anterior glottic web in an excised canine larynx model.

The main objective of the study is to model asymmetry within anterior glottic webs in excised larynges using sutures and apply aerodynamic and acoustic analyses. Anterior glottic webs (AGW) were modeled in eight excised larynges using sutures secured at the level of the glottis to mimic the scar tissue of the web. Each of the eight larynges were tested under three different pressure increments for each of the three models of AGW: symmetric, vertically asymmetric, and laterally asymmetric. Phonation threshold pressure (PTP) and flow (PTF) differed significantly across AGW conditions (p = 0.006 and p = 0.005, respectively). Additionally, vocal efficiency was significantly different among conditions (p = 0.005) as well as significantly lower in the asymmetric groups (p = 0.015 and p = 0.007). Perturbation measures were not significantly different across conditions. Correlation dimension (D2) was significantly different at PTP, 1.25 × PTP, and 1.5 × PTP (p = 0.003, p = 0.010, and p < 0.001, respectively) as well as significantly higher in the asymmetric groups at each pressure increment. The increased PTP, PTF, and D2 values as well as decreased vocal efficiency among the asymmetric conditions indicates a significant decrease in vocal function, and thus represents that asymmetries could be a contributing factor to the pathological symptoms associated with glottic webs.

The Protective Role of Autophagy in Human Vocal Fold Fibroblasts under Cigarette Smoke Extract Exposure: A New Insight into the Study of Reinke's Edema.

BACKGROUND/AIMS: Reinke's edema (RE), one of the most common benign lesions of the human vocal folds, has been associated with cigarette smoking. We have observed an abundant number of autophagosomes in the cytoplasm of fibroblasts in the lamina propria of human vocal folds under transmission electron microscopy in RE tissue. Thus, we conducted a study about autophagy induced by cigarette smoke extract (CSE) exposure in cultured human vocal fold fibroblasts (hVFFs). METHODS: Sampled tissues were cultured and exposed to varying levels of CSE. Immunochemistry staining and Western blot analyses were then performed on the cultures. RESULTS: We demonstrated that CSE significantly promoted intracellular reactive oxygen species accumulation and reduced the viability of hVFFs in a concentration-dependent manner. Both immunocytochemistry and Western blot analysis showed increased expression of the autophagy marker type II-membrane-associated light chain 3 in fibroblasts following 24 h of CSE exposure, indicating the upregulation of autophagy activity. Furthermore, the results demonstrate that the induction of autophagy played a protective role in hVFFs exposed to CSE. CONCLUSION: Autophagy can be induced by CSE in hVFFs, and it is a protective response of hVFFs to the exposure of CSE. This study provides a new insight into the process involved in the development of RE.

Combined type IIIB with bilateral type I thyroplasty for pitch lowering with maintenance of vocal fold tension.

To evaluate type IIIB thyroplasty using the excised larynx bench apparatus and determine how altering vocal fold contour by performing bilateral medialization of the inferior vocal fold affects phonation. This procedure could be performed in patients for whom pitch lowering is desirable, such as female-to-male transsexuals or male patients with mutational falsetto in whom intensive voice therapy was insufficient. Aerodynamic, acoustic, and high-speed videokymographic data were collected for nine larynges at three subglottal pressure inputs for each of three conditions: normal; type IIIB thyroplasty; and combined type IIIB with modified bilateral type I thyroplasty intended to create a more rectangular glottal configuration. Each larynx served as its own control. Phonation threshold flow (p = 0.005), phonation threshold power (p = 0.031), and airflow varied across conditions with highest values for type IIIB thyroplasty and lowest for the combined procedure. Fundamental frequency was significantly different (p < 0.001), decreasing by approximately 100 Hz from control to type IIIB trials, and then by approximately 15 Hz from IIIB to combined procedure trials. Vibratory amplitudes and intrafold phase difference were highest for type IIIB trials. Addition of bilateral inferior medialization to type IIIB thyroplasty provided some further decrease in frequency, but mostly served to increase tension, reduce airflow, and produce a vibratory pattern which more closely mirrored control trials. Exploration of this combined procedure in patients may be warranted if not completely satisfied with the results from type IIIB thyroplasty alone.

Effects of vocal fold lesions on particle deposition in a mouth-throat model: A numerical study.

OBJECTIVE: Dysphonia is very common worldwide and aerosol drug inhalation is an important treatment for patients with dysphonia. This study aimed to explore the effects of vocal fold (VF) lesions on the particle deposition pattern using computational modeling. METHODS: A realistic mouth-throat (MT) model of a healthy adult was constructed based on computed tomography images. Small and large vocal fold lesions were incorporated in the original model. A steady inhalation flowrate of 15 and 30 liter per minute (LPM) was used as the velocity inlet and monodisperse particles with diameters of 5 to 10 µm were simulated. RESULTS: Particles of larger size are more likely to be deposited in MT models, most of them distributed in oral cavity, oropharynx and supraglottis. The ideal sizes at 30 LPM ranged over 7-10 µm for healthy VFs and 6-8 µm for VF lesions. The best sizes at 15 LPM ranged over 6-8 µm for healthy VFs and 8-9 µm for VF lesions. CONCLUSION: Based on this study, VF lesions influence the deposition pattern in the glottis obviously. The ideal sizes differ at the flow rates of 15 and 30 LPM.

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.

Nonlinear Dynamic Analysis and Perturbation Measurement Used for Discriminating Pathological Voices and Their Correlations With Perceptual Evaluation.

OBJECTIVE: 1. To investigate the discriminatory and diagnostic power of nonlinear dynamic analysis measures concerning voices from normal, benign, and malignant voice disorders. 2. To study the correlations of nonlinear dynamic analysis measures with perceptual ratings to evaluate the reliability of the objective acoustic analysis in predicting severity of voice. METHOD: The perturbation analysis metrics used were Jitter%, Shimmer%, and signal-to-noise ratio. The nonlinear dynamic analysis metrics used were spectrum convergence ratio (SCR), nonlinear energy difference ratio (NEDR), and rate of divergence (ROD). Subjects were enrolled and divided into three groups based on laryngeal pathology: normal, benign, and malignant. Vowel sound and reading samples were recorded. Perceptual evaluation was applied to these voice samples to investigate correlations between metrics and auditory perception. RESULT: Each metric was capable of discriminating laryngeal pathology, except for SCR in the case of distinguishing between benign and malignant pathologies. Perturbation analysis parameters had a moderate ability to differentiate between normal and benign pathologies, but were unable to characterize malignant pathologies for certain diseases, such as Reinke's edema. All metrics significantly correlated with perceptual G scores. Nonlinear dynamic analysis was superior when applied to cases of severe dysphonia, where linear metrics such as Jitter% and Shimmer% tended to lose utility. NEDR and ROD were successful at differentiating between the different pathologies, whereas SCR could not discriminate between the benign and malignant groups. CONCLUSION: Perturbation and nonlinear dynamic analyses are comparable in their discriminating power with respect to normal and benign voices, and normal and malignant voices. The nonlinear dynamic analysis metrics NEDR and ROD may be superior in clinical settings with respect to discriminating voice pathology ranging from mild pathological voice to severe dysphonia, and with respect to discriminating benign and malignant voice. SCR was found unable to discriminate pathological voices.

Measurement of phonation threshold power in normal and disordered voice production.

OBJECTIVES: Phonation threshold pressure (PTP) and phonation threshold flow (PTF) are useful aerodynamic parameters, but each is sensitive to different disorders. A single comprehensive aerodynamic parameter sensitive to a variety of disorders might be beneficial in quantitative voice assessment. We performed the first study of phonation threshold power (PTW) in human subjects. METHODS: PTP and PTF were measured in 100 normal subjects, 19 subjects with vocal fold immobility, and 94 subjects with a benign mass lesion. PTW was calculated from these two parameters. In 41 subjects with a polyp, measurements were obtained before and after excision. Receiver operating characteristic (ROC) analysis was used to determine the ability of the three parameters to distinguish between controls and disordered groups. RESULTS: The PTW (p < 0.001), PTP (p < 0.001), and PTF (p < 0.001) were different among the three groups. All parameters decreased after polyp excision. PTW had the highest area under the ROC curve for all analyses. CONCLUSIONS: PTW is sensitive to the presence of mass lesions and vocal fold mobility disorders. Additionally, changes in PTW can be observed after excision of mass lesions. PTW could be a useful parameter to describe the aerodynamic inputs to voice production.

Modified Laryngeal Forceps for Arytenoid Cartilage Dislocation Caused by Endotracheal Intubation: A Retrospective Case-Control Pilot Study.

Background: Arytenoid cartilage dislocation is considered as a rare laryngeal injury and closed reduction is commonly used as the first choice for the arytenoid dislocation. However, the tools of closed reduction vary, and there is no dedicated tool for closed reduction, and the treatment outcome varies from person to person. This study compared the treatment outcome of the modified laryngeal forceps and traditional laryngeal forceps. Material and Methods: This study conformed to the strengthening the reporting of observational studies in epidemiology guidelines regarding retrospective studies. From May 2021 to February 2023, the records of 28 patients with arytenoid cartilage dislocation caused by endotracheal intubation were reviewed. They were divided into the traditional group (n = 14) and the modified group (n = 14) by gender. Indirect or direct laryngoscopy, video stroboscopy, high-resolution computed tomography, and cricoarytenoid joint 3-dimensional reconstruction were used to evaluate arytenoid position and motion. Clinical characteristics, voice function, procedural skill, and treatment outcome for each case were recorded. Results: Each patient was diagnosed with arytenoid dislocation caused by endotracheal intubation. There was no significant difference in the treatment outcome between the traditional group and the modified group (P > .05). However, the median time interval between closed reduction and the return of normal voice in the traditional group was 31.08 ± 10.56 days, which was significantly longer than the median time of 17.92 ± 3.83 days in the modified group (P < .05). Conclusion: Closed reduction with the modified laryngeal forceps under local anesthesia is an effective and safe procedure. Compared with traditional laryngeal forceps, the modified laryngeal forceps can shorten the treatment duration.

Effects of compound betamethasone on vocal fold wound healing in rabbit model: A preliminary study.

Objectives: The compound betamethasone is widely used to prevent scarring in dermatology. This study aims to explore the effects of compound betamethasone on vocal fold (VF) wound healing. Study design: Prospective animal study in rabbits. Methods: Eighteen rabbits underwent bilateral VF stripping and three rabbits served as controls. 0.1 mL of compound betamethasone (1 mL: betamethasone sodium phosphate 5 mg and betamethasone dipropionate 2 mg) was injected into the right VF of each rabbit, and 0.1 mL 0.9% saline was injected into the contralateral VF. Endoscopy was performed for morphologic observation. Six larynges were harvested for histological analysis at 3 days, 7 days, and 1 month. The VFs were stained with hematoxylin and eosin (H&E), Alcian blue, and Masson' trichrome staining. Results: In morphological analysis, there was no visible difference between betamethasone-treated and saline-treated VFs at 3 and 7 days. After 1 month, more VF scars appeared on the saline-treated VFs than the VFs treated with betamethasone. Inflammatory cell number showed significant difference between both VFs at 3 days (p = .037) and 7 days (p = .045). No significant different was found in epithelial thickness at 1 month between the betamethasone and saline groups. The collagen in the saline-treated VFs was significantly denser than that of the betamethasone-treated group (p = .037). There was also a significant increase in the level of hyaluronic acid (HA) in betamethasone-injected VFs in comparison to the saline-injected VFs (p = .006). Conclusions: Based on this study, compound betamethasone can improve VF healing. Our findings suggest that VF injection with compound betamethasone helps to minimize scarring by increasing HA level and decreasing collagen density.

Optimizing Aerodynamic Vocal Parameters by Varying Supraglottic Pressure Using "Controlled Supraglottic Pressure Phonation" in Healthy Subjects.

OBJECTIVE: The objective of this study is to introduce a novel method for semi-occluded vocal tract (SOVT) therapy called "controlled supraglottic pressure phonation," determine the mechanism by which supraglottic pressure contributes to lowering impedance during SOVT therapy, and provide the optimal supraglottic pressure range for SOVT exercises. METHODS: Twenty-five human subjects were assigned to one of five supraglottic pressure levels, 0, 2, 4, 6, and 8 cmH2O, which were controlled through a continuous positive airway pressure device. Subjects were asked to phonate during both a short- and long-duration task, in which vocal properties were measured before and after. At the end of each task, the subjects reported the levels of discomfort and phonation difficulty on a 0-10 scale to assess the subjective improvement of vocal economy. RESULTS: Significant differences were observed between pre- and post-task measurements for phonation threshold pressure for both the short-duration and long-duration tasks. Phonation threshold flow and frequency measurements were found to have no statistically significant differences. The subjective measures showed elevated discomfort in the higher pressure inputs for both tasks relative to no air. CONCLUSION: Higher supraglottic pressure levels will improve ease of phonation, but the treatment discomfort needs to be considered as well, yielding an optimal supraglottic pressure range of 4-6 cmH2O. "Controlled supraglottic pressure phonation" serves as an alternative to straw phonation that may produce additional benefits.

Vocal Vibration Opening Onset Position Abnormality in Patients With Adductor Spasmodic Dystonia by Using High-Speed Endoscopy.

OBJECTIVE: To analyze vocal fold vibration onset in patients with adductor laryngeal dystonia (ADLD) by analyzing vocal vibration opening onset position (VVOOP). STUDY DESIGN: Case-control study SETTING: A voice center. METHODS: Eleven patients with ADLD diagnosed in our voice center were enrolled in the ADLD group. Eleven healthy subjects matched by exact age and gender to the ADLD patients were selected as the control group. All subjects underwent laryngeal high-speed video endoscopy. VVOOP and its change were assessed by two otolaryngologists. The multiline video kymography was used to analyze the open quotient (OQ) and standard deviation of OQ. RESULTS: VVOOP had more than one position in 54.6% (6/11) of the patients with ADLD, which was higher than the control group (P < 0.05). VVOOP appeared in the front of the vocal fold in 54.6% (6/11) of patients with ADLD and in the back of the vocal fold in 81.8% (9/11) of patients with ADLD. VVOOP can be abnormal in 90.9% (10/11) of patients with ADLD, and the rate of VVOOP abnormality was higher than that of the control group (P < 0.05). Of 11, 6 (54.6%) patients with ADLD had a variable VVOOP; the variability rate of VVOOP was higher than that in the control group (P < 0.05). OQ and OQ standard deviation in the ADLD group were significantly greater than in the control group (P < 0.05). CONCLUSIONS: In patients with ADLD, vocal fold vibration was irregular, and VVOOP was abnormal and had a variable position and could reflect variability of the vocal vibration. LEVEL OF EVIDENCE: Level 4.

Effects of vocal fold adduction on the particle deposition in the glottis: A numerical analysis and in vitro assessment.

BACKGROUND: The efficacy of inhalation therapy depends on the drug deposition in the human respiratory tract. This study investigates the effects of vocal fold adduction on the particle deposition in the glottis. METHODS: A realistic mouth-throat (MT) geometry was built based on CT images of a healthy adult (MT-A). Mild (MT-B) and great (MT-C) vocal fold (VF) adduction were incorporated in the original model. Monodisperse particles range in size from 3 to 12 µm were simulated at inspiration flow rates of 15, 30 and 45 L per minute (LPM). The regional deposition of drug aerosols was performed in 3D-printed models and quantified using high-performance liquid chromatography. RESULTS: Both the numerical analysis and in vitro experiments show that most particles are deposited in the mouth, pharynx and supraglottis, while few are deposited in the glottis and subglottis. For most cases in MT-A, the particle quantity in glottis is lower than 0.02 N/mm2 at 15 and 30 LPM while they increase dramatically at 45 LPM. It peaked at 0.347 N/mm2 for 5-µm particles at 45 LPM in MT-B and 2.324 N/mm2 for 6-µm particles at 30 LPM in MT-C. The lowest drug mass faction in the glottis in vitro were found at 15 LPM for MT-A and MT-C, and at 30 LPM for MT-B, whereas it peaked at 45 LPM for all MT models, 0.71% in MT-A, 1.16% in MT-B, and 2.53% in MT-C, respectively. CONCLUSION: Based on the results of this study, larger particles are more likely to be deposited in the oral cavity, oropharynx, and supraglottis than in the glottis. However, particle deposition in the glottis generally increases with VF adduction and greater inspiratory flow rates.