Concurrent YAP/TAZ and SMAD signaling mediate vocal fold fibrosis.

Vocal fold (VF) fibrosis is a major cause of intractable voice-related disability and reduced quality of life. Excision of fibrotic regions is suboptimal and associated with scar recurrence and/or further iatrogenic damage. Non-surgical interventions are limited, putatively related to limited insight regarding biochemical events underlying fibrosis, and downstream, the lack of therapeutic targets. YAP/TAZ integrates diverse cell signaling events and interacts with signaling pathways related to fibrosis, including the TGF-ß/SMAD pathway. We investigated the expression of YAP/TAZ following vocal fold injury in vivo as well as the effects of TGF-ß1 on YAP/TAZ activity in human vocal fold fibroblasts, fibroblast-myofibroblast transition, and TGF-ß/SMAD signaling. Iatrogenic injury increased nuclear localization of YAP and TAZ in fibrotic rat vocal folds. In vitro, TGF-ß1 activated YAP and TAZ in human VF fibroblasts, and inhibition of YAP/TAZ reversed TGF-ß1-stimulated fibroplastic gene upregulation. Additionally, TGF-ß1 induced localization of YAP and TAZ in close proximity to SMAD2/3, and nuclear accumulation of SMAD2/3 was inhibited by a YAP/TAZ inhibitor. Collectively, YAP and TAZ were synergistically activated with the TGF-ß/SMAD pathway, and likely essential for the fibroplastic phenotypic shift in VF fibroblasts. Based on these data, YAP/TAZ may evolve as an attractive therapeutic target for VF fibrosis.

Laryngeal Pathologies Associated with the Genre of Singing and Professional Singing Status in a Treatment-Seeking Population.

OBJECTIVES/HYPOTHESIS: Singers have high vocal demands and are at increased risk of developing voice disorders. Different singing genres place different technical demands on the voice. However, differences in laryngeal pathology based on genre have not been well-researched. The purpose of this study was to determine the prevalence of laryngeal pathology in different genres of professional and amateur singers who present with a voice complaint. STUDY DESIGN: Retrospective review. METHODS: Retrospective review of patients seen at a tertiary laryngology practice. Self-identified singers who reported their primary singing genre and categorized their singing as a full-time job, part-time job, or amateur involvement were included. Type and prevalence of pathology were calculated based on genre and professional status. RESULTS: Of the 302 self-identified singers, 54% (n = 164) had laryngeal pathology. Among those with pathology, the most common finding was fibrotic lesion (38.4%, 63/164). Genres in which a majority of singers had pathology were other (69.2%, 9/13), choral (64.7%, 11/17), pop (63.2%, 12/19), musical theater (61.4%, 43/70), country (100%, 4/4), and Latin (100%, 2/2). The highest prevalence of pathology was seen in part-time professional singers (62.2%, 41/66) and full-time professionals (60.8%, 62/102), compared to amateurs (45.1%, 60/133). CONCLUSIONS: Laryngeal pathology is prevalent in singers presenting with a voice complaint. Regardless of genre or professional status, fibrotic lesions were the most common pathological finding. This study provides preliminary data on the prevalence of different laryngeal pathologies found in singers by genre and degree of professional involvement. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:2076-2080, 2021.

A Wearable Skinlike Ultra-Sensitive Artificial Graphene Throat.

Most mute people cannot speak due to their vocal cord lesion. Herein, to assist mute people to "speak", we proposed a wearable skinlike ultrasensitive artificial graphene throat (WAGT) that integrated both sound/motion detection and sound emission in single device. In this work, the growth and patterning of graphene can be realized at the same time, and a thin poly(vinyl alcohol) film with laser-scribed graphene was obtained by a water-assisted transferring process. In virtue of the skinlike and low-resistant substrate, the WAGT has a high detection sensitivity (relative resistance changes up to 150% at 133 Ω) and an excellent sound-emitting ability (up to 75 dB at 0.38 W power and 2 mm distance). On the basis of the excellent mechanical-electrical performance of graphene structure, the sound detecting and emitting mechanisms of WAGT are realized and discussed. For sound detection, both the motion of larynx and vibration of vocal cord contribute to throat movements. For sound emission, a thermal acoustic model for WAGT was established to reveal the principle of sound emitting. More importantly, a homemade circuit board was fabricated to build a dual-mode system, combining the detection and emitting systems. Meanwhile, different human motions, such as strong and small throat movements, were also detected and transformed into different sounds like "OK" and "NO". Therefore, the implementation of these sound/motion detection acoustic systems enable graphene to achieve device-level applications to system-level applications, and those graphene acoustic systems are wearable for its miniaturization and light weight.

Vocal tract symptoms: Severity and frequency in patients on statins.

The objective of the study was to analyze the frequency and severity of vocal tract symptoms in patients on statins. A total of 73 patients were enrolled in this study, 44 patients who were taking statins and 29 controls not taking statins. The severity and frequency of vocal tract discomfort was assessed using the Vocal Tract Discomfort scale. The most frequent vocal tract symptom in patients on statins was dryness followed by tightness and lump sensation. The difference in the mean of the total score and in the mean frequency of any vocal tract symptom was not significant between patients taking statins and controls. The most severe (highest mean values) vocal tract symptom in patients taking statins also was dryness followed by tightness and lump sensation. The difference in the mean of the total score and in the mean severity of any vocal tract symptom between patients taking statins and controls was not significant. This study failed to demonstrate a higher prevalence or severity of vocal tract symptoms in patients receiving statins. Despite the lack of a significant difference in the means of vocal tract discomfort symptom frequency and severity, this study carries clinical significance when considering that a higher prevalence and severity of vocal tract discomfort symptoms should alert physicians to the possible development of statin-induced myotoxicity in the laryngopharyngeal complex.

Impact of vocal fold augmentation and laryngoplasty on dyspnea in patients with glottal incompetence.

OBJECTIVES/HYPOTHESIS: Given that the vocal folds are active organs of respiration, reports of dyspnea in the context of glottic insufficiency are not uncommon. We hypothesize that improved glottal closure via framework surgery or vocal fold augmentation improves dyspnea symptoms. STUDY DESIGN: Retrospective review. METHODS: Charts of patients undergoing procedures to correct glottal insufficiency, either via vocal fold augmentation (VFA) or medialization laryngoplasty (ML) between December 2012 and September 2015 were reviewed (n = 189). Modified Borg Dyspnea Scale (MBDS) and Modified Medical Research Council Dyspnea Scale (MMRCDS) data were collected before and after intervention. Age, body mass index (BMI), and sex, as well as pulmonary and cardiac comorbidities were considered. Subgroup analysis was performed on individuals with subjective dyspnea prior to intervention. RESULTS: For the entire cohort, differences in the MMRCDS and MBDS were not statistically different pre- and postintervention (P = .20 and P = .12, respectively). Patients with BMI <30 experienced more improvement on the MBDS (P = .03). Both the MMRCDS and MMBDS improved post-procedure (P = .001 and P = .001, respectively) in patients reporting dyspnea prior to intervention. CONCLUSIONS: Patients with glottic insufficiency and dyspnea prior to intervention to improve glottic closure had a significant reduction in dyspnea following treatment. Conversely, subjects without complaints of dyspnea prior to intervention had variable outcomes with regard to dyspnea symptoms. Additionally, based on data from the entire cohort, VFA or ML did not worsen dyspnea symptoms. These data may assist in counseling and/or selection of patients considered for procedures to improve glottic closure. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:427-429, 2018.

Background Factors and Subjective Voice Symptoms in Patients with Acquired Vocal Fold Scarring and Sulcus Vocalis.

OBJECTIVE: Vocal fold scarring (VFS) and sulcus vocalis (SV) often result in severe and chronic voice disorders. This study compares subjective voice complaints as rated with the Voice Handicap Index and etiological factors for patients with VFS and SV. PATIENTS AND METHODS: Data were collected from the medical records at the Department of Otorhinolaryngology, Karolinska University Hospital, for 27 VFS patients and 27 SV patients. Descriptive background factors were compared between the groups and data were compared from the Swedish Voice Handicap Index (Sw-VHI) questionnaires. RESULTS: Previous laryngeal surgery/trauma was significantly more common for the patients with VFS. The SV group had significantly more persistent dysphonia since childhood. It was significantly more common to have a non-Germanic language origin among the SV patients. VFS and SV rated high for the total median Sw-VHI scores. The VFS group's total Sw-VHI and the three domain scores were significantly higher compared to the SV group. The physical domain showed a significantly higher score when compared to the functional and emotional domains in the SV cohort and when compared to the emotional domain in the VFS cohort. CONCLUSION: There are significant differences between the VFS group and SV group regarding etiological factors as well as the Sw-VHI. The degree and profile of VHI should be considered when selecting patients and evaluating the result of new treatments for this group of patients.

Visualization and Estimation of Vibratory Disturbance in Vocal Fold Scar Using High-Speed Digital Imaging.

OBJECTIVE: To explore the method to visualize and quantify the abnormality of vocal fold vibration in vocal fold scar (VFS) using high-speed digital imaging (HSDI). METHODS: HSDI was performed on 12 patients (2 men and 10 women) with VFS and 46 vocally healthy subjects (17 men and 29 women), and the obtained data were quantitatively evaluated by frame-by-frame analysis, laryngotopography (LTG), single-line and multiline kymography, and glottal area waveform. RESULTS: Visualization of a scarred area was feasible in 75% of VFS in the present study using LTG. Quantitative HSDI analysis revealed that VFS had poorer glottal closure (eg, larger open quotients, larger minimal glottal area), reduced vibration in a scarred area (eg, smaller mucosal wave magnitude, mucosal wave persistence, lateral peak index), and greater asymmetry (eg, amplitude difference, mucosal wave magnitude difference, lateral phase difference) than the control group. Correlation study revealed moderate correlations between HSDI-derived parameters and conventional acoustic or aerodynamic parameters (eg, period perturbation quotient). CONCLUSIONS: HSDI is considered to be useful in the diagnosis of VFS, visualization of a scarred area, and quantification of vibratory abnormality.

Vocal fold hyalinosis in Urbach-Wiethe disease, a rare cause of hoarseness.

BACKGROUND: Lipoid proteinosis is an autosomal recessive disorder characterized by hyalin deposits in the skin and mucosa of the upper aerodigestive tract; currently, no treatment exists. Nearly all patients experience hoarseness and speech difficulties, due to hyalin deposition in the vocal folds and diminished mobility in infiltrated lips, tongue, and palate. METHODS: We describe a patient with extensive hyalin plaques on the vocal folds, which resulted in near-aphonic hoarseness. Hyalin deposits in the vocal folds and skin were treated with laser resection. RESULTS: Both the vocal folds and skin improved in appearance, with smoother surface epithelium. However, the patient's speech remained impaired, due to extensive hyalin plaques in the mouth, tongue, and lips. The voice improved only temporarily. CONCLUSIONS: Laser resection of hyalin plaques in the vocal folds and skin is a feasible treatment for lipoid proteinosis. However, speech may remain severely limited, due to impaired tongue and lip movement.

The VCDQ--a Questionnaire for symptom monitoring in vocal cord dysfunction.

BACKGROUND: Vocal cord dysfunction (VCD) typically involves abnormal adduction of the vocal cords during inspiration, mimics the symptoms of asthma and leads to the prescription of ineffective medications. OBJECTIVE: We aimed to develop a clinical tool to monitor symptoms and response to treatment in confirmed VCD. METHODS: We collated symptoms of VCD from focus groups comprising patients and healthcare professionals; phrases describing these symptoms were assessed for face validity and internal correlation and rated for importance. The resultant 12-item questionnaire (VCDQ) rated the impact of each on a 5-point Likert scale (total score range 12-60) and was tested for reliability, concurrent validity and performance in 31 patients with endoscopically confirmed VCD (± asthma), 29 asthmatics with no history of VCD and 14 healthy controls. We assessed response to speech and language therapy and the minimal important difference by measuring the VCDQ pre- and post- therapy in a 20 new patients. RESULTS: The VCDQ had excellent test-retest reliability and differentiated VCD vs. healthy (Mann-Whitney U-test: z = -5.390, P < 0.001) and asthma (z = -5.730, P < 0.001). All patients improved post-therapy, assessed both by a global rating of change score (GRCS) and by the VCDQ [median (IQR) score pre-therapy 50.5 (48.0 - 54.8), post-therapy 35.0 (29.3 - 41.8), P < 0.001]. The minimal important difference in the VCDQ associated with a rating of 'minimally better' on the GRCS was 4 points. CONCLUSIONS AND CLINICAL RELEVANCE: The VCDQ is a valid and responsive tool suitable for measuring changes in symptoms in patients with VCD. It also gives insight into which symptoms are important to patients and could guide future therapy refinements. Future assessments of novel therapies for this condition should use an appropriately validated tool such as the VCDQ to measure response.

Classification of laryngeal disorders based on shape and vascular defects of vocal folds.

Vocal fold disorders such as laryngitis, vocal nodules, and vocal polyps may cause hoarseness, breathing and swallowing difficulties due to vocal fold malfunction. Despite the fact that state of the art medical imaging techniques help physicians to obtain more detailed information, difficulty in differentiating minor anomalies of vocal folds encourages physicians to research new strategies and technologies to aid the diagnostic process. Recent studies on vocal fold disorders note the potential role of the vascular structure of vocal folds in differential diagnosis of anomalies. However, standards of clinical usage of the blood vessels have not been well established yet due to the lack of objective and comprehensive evaluation of the vascular structure. In this paper, we present a novel approach that categorizes vocal folds into healthy, nodule, polyp, sulcus vocalis, and laryngitis classes exploiting visible blood vessels on the superior surface of vocal folds and shapes of vocal fold edges by using image processing techniques and machine learning methods. We first detected the vocal folds on videolaryngostroboscopy images by using Histogram of Oriented Gradients (HOG) descriptors. Then we examined the shape of vocal fold edges in order to provide features such as size and splay portion of mass lesions. We developed a new vessel centerline extraction procedure that is specialized to the vascular structure of vocal folds. Extracted vessel centerlines were evaluated in order to get vascular features of vocal folds, such as the amount of vessels in the longitudinal and transverse form. During the last step, categorization of vocal folds was performed by a novel binary decision tree architecture, which evaluates features of the vocal fold edge shape and vascular structure. The performance of the proposed system was evaluated by using laryngeal images of 70 patients. Sensitivity of 86%, 94%, 80%, 73%, and 76% were obtained for healthy, polyp, nodule, laryngitis, and sulcus vocalis classes, respectively. These results indicate that visible vessels of vocal folds can act as a prognostic marker for vocal fold pathologies, as well as the vocal fold shape features, and may play a critical role in more effective diagnosis.

Dexamethasone Controlled Release on TGF-ß1 Treated Vocal Fold Fibroblasts.

OBJECTIVE: Corticosteroids may be beneficial in treating vocal fold scarring. Current drug delivery methods do not permit controlled corticosteroid release. Here we investigate the effects of poly-lactic-co-glycolic acid (PLGA) microparticles loaded with the corticosteroid dexamethasone in reducing collagen synthesis and inflammation in vocal fold fibroblasts treated with and without TGF-ß1. STUDY DESIGN: Experimental, in vitro study. METHODS: PLGA microparticles of differing molecular weight and terminating moieties were synthesized using a hydrogel template method. The release of dexamethasone was characterized from these microparticles over 4 days. Based on the release studies, ester-terminated low molecular weight PLGA microparticles were loaded with dexamethasone and applied to TGF-ß1 treated vocal fold fibroblasts for 4 days. Quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assays (ELISAs) were used to assess the effects of released dexamethasone on collagen synthesis and inflammatory mediators. RESULTS: COL3A1 and COL1A2 were significantly down-regulated after exposure to ester-terminated low molecular weight PLGA microparticles loaded with dexamethasone. The loaded microparticles also reduced interleukin-6 synthesis. CONCLUSION: These data show promise in using a PLGA microparticle-based delivery system to control dexamethasone release over 4 days. Our findings lay the groundwork for developing more effective treatments for vocal fold scarring.

Homeostasis of hyaluronic acid in normal and scarred vocal folds.

OBJECTIVES/HYPOTHESIS: Vocal fold scarring is one of the most challenging laryngeal disorders to treat. Hyaluronic acid (HA) is the main component of lamina propria, and it plays an important role in proper vocal fold vibration and is also thought to be important in fetal wound healing without scarring. Although several animal models of vocal fold scarring have been reported, little is known about the way in which HA is maintained in vocal folds. The purpose of this study was to clarify the homeostasis of HA by examining the expression of hyaluronan synthase (Has) and hyaluronidase (Hyal), which produce and digest HA, respectively. STUDY DESIGN: Experimental prospective animal study. METHODS: Vocal fold stripping was performed on 38 Sprague-Dawley rats. Vocal fold tissue was collected at five time points (3 days-2 months). Expression of HA was examined by immunohistochemistry, and messenger RNA (mRNA) expression of Has and Hyal was examined by real-time polymerase chain reaction and in-situ hybridization. RESULTS: In scarred vocal folds, expression of Has1 and Has2 increased at day 3 together with expression of HA and returned to normal at 2 weeks. At 2 months, Has3 and Hyal3 mRNA showed higher expressions than normal. CONCLUSIONS: Expression patterns of Has and Hyal genes differed between normal, acute-scarred, and chronic-scarred vocal folds, indicating the distinct roles of each enzyme in maintaining HA. Continuous upregulation of Has genes in the acute phase may be necessary to achieve scarless healing of vocal folds.

A rabbit vocal fold laser scarring model for testing lamina propria tissue-engineering therapies.

OBJECTIVES/HYPOTHESIS: To develop a vocal fold scarring model using an ablative laser in the rabbit as a platform for testing bioengineered therapies for missing or damaged lamina propria. STUDY DESIGN: Prospective controlled animal study. METHODS: An optimal laser energy level was first determined by assessing the depths of vocal fold injury created by a Holmium:YAG laser at various energy levels on fresh cadaveric rabbit larynges. The selected energy level was then used to create controlled unilateral injuries in vocal folds of New Zealand white rabbits, with the contralateral folds serving as uninjured controls. After 4 weeks, the larynges were harvested and subjected to excised-larynx phonation with high-speed imaging and immunohistochemical staining for collagen types I and III, elastin, and hyaluronic acid (HA) with quantitative histological analysis. RESULTS: A total of 1.8 joules produced full-thickness injury of the lamina propria without extensive muscle injury. After 4 weeks, the injured vocal folds vibrated with reduced amplitude (P = 0.036) in excised-larynx phonation compared to normal vocal folds. The injured vocal folds contained a higher relative density of collagen type I (P = 0.004), higher elastin (P = 0.022), and lower HA (P = 0.030) compared to normal controls. Collagen type III was unchanged. CONCLUSIONS: With its potential for higher precision of injury, this laser vocal fold scarring model may serve as an alternative to scarring produced by cold instruments for studying the effects of vocal fold lamina propria bioengineered therapies.

Correlation among the dysphonia severity index (DSI), the RBH voice perceptual evaluation, and minimum glottal area in female patients with vocal fold nodules.

OBJECTIVES: To investigate the clinical significance and correlation of the dysphonia severity index (DSI), the RBH (roughness [R]; breathiness [B]; hoarseness [H]) perceptual voice quality evaluation, and minimum glottal area (MGA) in patients with vocal fold nodules and validate the practicality of the DSI further. METHODS: The DSI evaluation, the voice RBH perceptual evaluation, and the MGA were performed on 30 female patients with vocal fold nodules (the patient group) and 30 female volunteers with normal voices (the control group). The DSI determination was calculated using the following formula: DSI = 0.13 × MPT + 0.0053 × F(0)-High - 0.26 × I-Low - 1.18 × Jitter(%) + 12.4. The RBH evaluation was graded according to four scales. The MGA was measured by KayPENTAX Kips (7105) software. The differences among the DSI, the RBH grade, and MGA of the patients were compared. RESULTS: The median DSI values of the patient group and the control group were -0.81 and 3.79, respectively, and the difference was statistically significant (P < 0.01). The median MGA of the patient group and the control group were 355.5 and 121, respectively, and the difference was statistically significant (P < 0.01). DSI exhibited moderate negative correlation with R (rP = -0.686, P < 0.01), B (rP = -0.609, P < 0.01), and H (rP = -0.487, P < 0.01). MGA demonstrated moderate positive correlation with R (rP = 0.667, P < 0.01), B (rP = 0.545, P < 0.01), and H (rP = 0.449, P < 0.01), whereas MGA showed strong negative correlation with DSI (rP = -0.888, P < 0.01). CONCLUSIONS: The application of the DSI as an objective parameter to evaluate dysphonia in female patients with vocal nodules has significant clinical application and good correlation with MGA measurement.

Numerical simulation of glottal flow.

In cases of permanent immobility of both vocal folds patients have difficulties with breathing but rarely with voicing. However, clinical experience shows that the shape of the larynx (voice box) seems to have a significant influence on the degree of airflow and breathing pattern. In order to find an optimal geometry of the larynx in terms of easiness for breathing after the surgical change of vocal folds or false vocal cords (ventricular folds), a set of numerical simulations of glottal flow for weakly compressible Navier-Stokes equations has been performed. We compare airflow resistance and volumetric flow rate for several geometry concepts for inspiration as well as expiration. Finally, we discuss the optimal geometry with respect to the quality of breathing.