Acoustics and aerodynamic effects following glottal and infraglottal medialization in an excised larynx model.

OBJECTIVE: This study aimed to investigate the impact of the implant's vertical location during Type 1 Thyroplasty (T1T) on acoustics and glottal aerodynamics using excised canine larynx model, providing insights into the optimal technique for treating unilateral vocal fold paralysis (UVFP). METHODS: Measurements were conducted in six excised canine larynges using Silastic implants. Two implant locations, glottal and infraglottal, were tested for each larynx at low and high subglottal pressure levels. Acoustic and intraglottal flow velocity field measurements were taken to assess vocal efficiency (VE), cepstral peak prominence (CPP), and the development of intraglottal vortices. RESULTS: The results indicated that the implant's vertical location significantly influenced vocal efficiency (p = 0.045), with the infraglottal implant generally yielding higher VE values. The effect on CPP was not statistically significant (p = 0.234). Intraglottal velocity field measurements demonstrated larger glottal divergence angles and stronger vortices with the infraglottal implant. CONCLUSION: The findings suggest that medializing the paralyzed fold at the infraglottal level rather than the glottal level can lead to improved vocal efficiency. The observed larger divergence angles and stronger intraglottal vortices with infraglottal medialization may enhance voice outcomes in UVFP patients. These findings have important implications for optimizing T1T procedures and improving voice quality in individuals with UVFP. Further research is warranted to validate these results in clinical settings.

Comparative Treatment Outcomes for Idiopathic Subglottic Stenosis: 5-Year Update.

The North American Airway Collaborative (NoAAC) previously published a 3-year multi-institutional prospective cohort study showing variation in treatment effectiveness between 3 primary surgical techniques for idiopathic subglottic stenosis (iSGS). In this report, we update these findings to include 5 years of data evaluating treatment effectiveness. Patients in the NoAAC cohort were re-enrolled for 2 additional years and followed using the prespecified published protocol. Consistent with prior data, prospective observation of 487 iSGS patients for 5 years showed treatment effectiveness differed by modality. Cricotracheal resection maintained the lowest rate of recurrent operation (5%), followed by endoscopic resection with adjuvant medical therapy (30%) and endoscopic dilation (50%). These data support the initial observations and continue to provide value to providers and patients navigating longitudinal decision-making. Level of evidence: 2-prospective cohort study.

Killian Jamieson Diverticulum, the Great Mimicker: A Case Series and Contemporary Review.

OBJECTIVE: To assess barium esophagram (BAS) as a diagnostic marker for patients with Killian Jamieson diverticula (KJD). METHODS: Prospective, multicenter cohort study of individuals enrolled in the Prospective OUtcomes of Cricopharyngeus Hypertonicity (POUCH) Collaborative. Patient demographics, comorbidities, radiographic imaging reports, laryngoscopy findings, patient-reported outcome measures (PROM), and operative reporting were abstracted from a REDCap database and summarized using means, medians, percentages, frequencies. Paired t-tests and Wilcoxon Signed Rank test were used to test pre- to post-operative differences in RSI, EAT-10, and VHI-10 scores. Diagnostic test evaluation including sensitivity, specificity, positive, and negative predictive value with 95% confidence intervals were calculated comparing BAS findings to operative report. RESULTS: A total of 287 persons were enrolled; 13 (4%) patients were identified with confirmed KJD on operative reports. 100% underwent open transcervical excision. BAS has a 46.2% (95% confidence interval [CI]: 23.2, 70.9) sensitivity and 97.8% (95% CI: 95.3, 99.0) specificity in detecting a KJD and 50% (95% CI: 25.4, 74.6) positive predictive value but 97.4% (95%CI: 94.8, 98.7) negative predictive value. Preoperatively, patients reported mean (SD) RSI and EAT-10 of 19.4 (9) and 8.3 (7.5) accordingly. Postoperatively, patients reported mean (SD) RSI and EAT-10 as 5.4 (6.2) and 2.3 (3.3). Both changes in RSI and EAT-10 were statistically significant (p = 0.008, p = 0.03). CONCLUSION: KJD are rare and represent <5% of hypopharyngeal diverticula undergoing surgical intervention. Open transcervical surgery significantly improves symptoms of dysphagia. BAS has high specificity but low sensitivity in detecting KJD. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:2110-2115, 2023.

Acoustic Screening of the "Wet voice": Proof of Concept in an ex vivo Canine Laryngeal Model.

BACKGROUND: Current protocols for bedside swallow evaluation have high rates of false negative results. Though experts are not consistently able to screen for aspiration risk by assessing vocal quality, there is emerging evidence that vocal acoustic parameters are significantly different in patients at risk of aspiration. Herein, we aimed to determine whether the presence of material on the vocal folds in an excised canine laryngeal model may have an impact on acoustic and aerodynamic measures. METHODS: Two ex vivo canine larynges were tested. Three liquids of different viscosities (1:100 diluted glycerin, pure glycerin, and honey-thick Varibar) were placed on the vocal folds at a constant volume. Acoustic and aerodynamic measures were obtained in both adducted and abducted vocal fold configurations. Intraglottal high-speed imaging was used to approximate the maximum divergence angle of the larynges in the studied conditions and examine its relationship to vocal efficiency (VE) and acoustic measures. RESULTS: In glottic insufficiency conditions only, we found that several acoustic parameters could predict the presence of material on the vocal folds. Based on the combination of the aerodynamic and acoustic data, we found that decreased spectral energy in the higher harmonics was associated with decreased VE in the presence of material on the vocal folds and/or glottic insufficiency. CONCLUSION: Decreased spectral energy in the higher harmonics of the voice was found to be a potential biomarker of swallowing dysfunction, as it correlates with decreased vocal efficiency due to material on the vocal folds and/or glottic insufficiency, both of which are known risk factors for aspiration. LEVEL OF EVIDENCE: NA Laryngoscope, 133:2517-2524, 2023.

An Ex-vivo Model Examining Acoustics and Aerodynamic Effects Following Medialization With and Without Arytenoid Adduction.

OBJECTIVES/HYPOTHESIS: Quantify differences in acoustics and intraglottal flow fields between Thyroplasty Type 1 (TT1) with and without arytenoid adduction (AA) using excised canine larynx model. STUDY DESIGN: Basic science experiments using excised larynges. METHODS: Surgical procedures were implemented in eight excised canine larynges. Acoustics and intraglottal flow measurements were taken at low and high subglottal pressures in each experimental setup. RESULTS: In all larynges, vocal efficiency (VE) and cepstrum peak prominence (CPP) were higher, and the mean phonatory flow rate was lower in TT1 with AA than without AA. The glottal asymmetry is reduced with AA and promotes the formation of stronger vortices in the glottal flow during the closing phase of the vibrating folds. CONCLUSIONS: Findings suggest a clear acoustic and aerodynamic benefit to the addition of AA when performing TT1. It shows significant improvement in CPP, translating to decreased breathiness and dysphonia and increased VE, leading to easier and more sustainable phonation. Stronger intraglottal vortices are known to be correlated with the loudness of voice produced by phonation. LEVEL OF EVIDENCE: N/A Laryngoscope, 133:621-627, 2023.

Cricopharyngeus Muscle Dysfunction and Hypopharyngeal Diverticula (e.g., Zenker): A Multicenter Study.

OBJECTIVE: To describe demographics and imaging and compare findings and symptoms at presentation in a large cohort of persons with cricopharyngeus muscle dysfunction (CPMD) with and without hypopharyngeal diverticula. METHODOLOGY: Prospective, multicenter cohort study of all individuals enrolled in the Prospective OUtcomes of Cricopharyngeal Hypertonicity (POUCH) Collaborative. Patient survey, comorbidities, radiography, laryngoscopy findings, and patient-reported outcome measures (e.g., Eating Assessment Tool [EAT-10]) data were abstracted from a REDCap database and summarized using means, medians, percentages, and frequencies. Diagnostic categories were compared using analysis of variance. RESULTS: A total of 250 persons were included. The mean age (standard deviation [SD]) of the cohort was 69.0 (11.2). Forty-two percent identified as female. Zenker diverticula (ZD) was diagnosed in 85.2%, 9.2% with CPMD without diverticula, 4.4% with a Killian Jamieson diverticula (KJD), and 1.2% traction-type diverticula. There were no differences between diagnostic categories in regard to age, gender, and duration of symptoms (p = 0.25, 0.19, 0.45). The mean (SD) EAT-10 score for each group was 17.1 (10.1) for ZD, 20.2 (9.3) for CPMD, and 10.3 (9.4) for KJD. Patients with isolated CPMD had significantly greater EAT-10 scores compared to the other diagnostic groups (p = 0.03). CONCLUSION: ZD is the most common, followed by CPMD without diverticula, KJD, and traction-type. Patients with isolated obstructing CPMD may be more symptomatic than persons with ZD or KJD. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:1349-1355, 2023.

Fluid-Structure Interaction Analysis of Aerodynamic and Elasticity Forces During Vocal Fold Vibration.

The effect of the intraglottal vortices on the glottal flow waveform was explored using flow-structure-interaction (FSI) modeling. These vortices form near the superior aspect of the vocal folds during the closing phase of the folds' vibration. The geometry of the vocal fold was based on the well-known M5 model. The model did not include a vocal tract to remove its inertance effect on the glottal flow. Material properties for the cover and body layers of the folds were set using curve fit to experimental data of tissue elasticity. A commercially available FSI solver was used to perform simulations at low and high values of subglottal input pressure. Validation of the FSI results showed a good agreement for the glottal flow and the vocal fold displacement data with measurements taken in the excised canine larynx model. The simulations result further support the hypothesis that intraglottal vortices can affect the glottal flow waveform, specifically its maximum flow declination rate (MFDR). It showed that MFDR occurs at the same phase when the highest intraglottal vortical strength and the negative pressure occur. It also showed that when MFDR occurs, the magnitude of the aerodynamic force acting on the glottal wall is greater than the elastic recoil force predicted in the tissue. These findings are significant because nearly all theoretical and computational models that study the vocal fold vibrations mechanism do not consider the intraglottal negative pressure caused by the vortices as an additional closing force acting on the folds.

Computational Modeling of Nasal Drug Delivery Using Different Intranasal Corticosteroid Sprays for the Treatment of Eustachian Tube Dysfunction.

Eustachian tube dysfunction (ETD) is a common otolaryngologic condition associated with decreased quality of life. The first-line treatment of ETD is intranasal corticosteroid sprays (INCS). Computational fluid dynamics (CFD) was used to study particle deposition on the Eustachian tube (ET) using two commercial INCS (Flonase and Sensimist). Simulations also considered the effects of nostril side, insertion depth, insertion angle, cone spray angle, inhaling rates, wall impingement treatment, and fluid film. Flonase and Sensimist produced different particle size distributions and sizes. Sensimist droplets are smaller, less sensitive to asymmetry in nostrils anatomy and variation in insertion angle, and therefore can reach the posterior nasopharynx more readily. Flonase produces larger particles with greater inertia. Its particles deposition is more sensitive to intrasubject variation in nasal anatomy and insertion angles. The particle deposition on the ET was sensitive to the wall impingement model. The deposition on the ET was insignificant with adherence only <0.15% but increased up to 1-4% when including additional outcomes rebound and splash effects when droplets impact with the wall. The dose redistribution with the fluid film is significant but plays a secondary effect on the ET deposition. Flonase aligned parallel with the hard palate produced 4% deposition efficiency on the ET, but this decreased <0.14% at the higher insertion angle. INCS with larger droplet sizes with a small insertion angle may be more effective at targeting droplet deposition on the ET opening.

Surgery and Adjuvant Therapy Improve Derkay Scores in Adult and Pediatric Respiratory Papillomatosis.

OBJECTIVES/HYPOTHESIS: Comparing Derkay anatomical score at time of procedure, disease characteristics, and mean treatment interval among adult and pediatric patients with recurrent respiratory papillomatosis (RRP). STUDY DESIGN: Restrospective study. METHODS: Retrospective review of juvenile-onset (JO) and adult-onset (AO) RRP patients treated longitudinally at pediatric and adult institutions from 1999 to 2019. Patients were included if they had a tissue diagnosis of papilloma and had at least a 12-month follow-up. RESULTS: One hundred and twelve patients met inclusion criteria (68 JO-RRP and 44 AO-RRP). All patients were stratified into either potassium titanyl phosphate (KTP) (n = 42), CO2 (n = 21), or microdebrider (n = 49) treatment groups. The Derkay score improved between first and last procedure in the KTP group (mean difference, 3.5; P < .001), CO2 group (mean difference, 4.4; P < .001), and microdebrider group (mean difference, 4.1; P < .001), but overall improvement did not differ across groups (P = .73). Baseline mean to last mean Derkay score improved for nine patients during bevacizumab treatments (mean difference, 3.0; P = .01) but did not improve for these same patients during an interval prior to receiving bevacizumab treatments. Baseline mean to last mean Derkay score improved for 19 patients during cidofovir treatments (mean difference, 3.84; P < .001) but did not improve for these same patients during the interval prior to receiving cidofovir treatments. The AO-RRP population had more patients with dysplasia (50%) compared to JO-RRP population (10%) (P < .001). CONCLUSION: Various surgical modalities appear to be equally effective treatments for RRP. Adult and pediatric patients have decreased recurrent disease burden when receiving bevacizumab or cidofovir. AO-RRP patients have more concomitant dysplasia. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:2420-2426, 2022.

Surgical Treatment of Acquired Velopharyngeal Insufficiency in Adults With Dysphagia and Dysphonia.

OBJECTIVES: Velopharyngeal insufficiency (VPI) is a form of velopharyngeal dysfunction caused by abnormal or insufficient anatomy. This process is known to be associated with dysphagia and dysphonia but surgical interventions for these complex patients have not been well studied. The current study characterized a small cohort of adult patients with acquired VPI, dysphonia, and dysphagia, as well as associated surgical interventions. METHODS: A retrospective descriptive case series of 22 (N = 22) adult patients over a 6-year period with acquired VPI and varying degrees of dysphagia and dysphonia was described from a multi-disciplinary voice and swallowing clinic. Perceptual assessment, nasopharyngoscopy, fluoroscopic swallowing assessment, and patient reported outcomes were reviewed to characterize the cohort. RESULTS: VPI etiologies included: stroke (n = 4), head and neck cancer (n = 5), brainstem lesions (n = 5), trauma (n = 5), and other/unknown (n = 3). All 22 patients underwent nasopharyngoscopy and were categorized as having unilateral (n = 13), central (n = 4), or no (n = 5) velopharyngeal deficits. Seventeen patients (77.2%) underwent modified barium swallow studies, revealing that soft palate elevation scored least impaired among patients with no VPI, and most impaired among patients with unilateral VPI deficits. All 22 patients underwent some form of surgical intervention for VPI, with 14 (63.6%) of those patients requiring additional surgical revision. CONCLUSION: This series is one of the first to the authors' knowledge to characterize a cohort of individuals with VPI, dysphagia, and dysphonia and associated surgical interventions.

Are Indoor Cycling Instructors Riding Their Way to Vocal Injury? Acute Effects of a Single Class on Measures of Voice Production.

OBJECTIVE/HYPOTHESIS: There is an increased need for vocal education programs in group fitness instructors due to the reported risk of phonotraumatic injury in this population. Most research has focused on aerobics class instructors with limited research detailing the vocal demand response of cycling instruction, specifically. We hypothesized that instruction of a single indoor cycling class would produce evidence of acute vocal fold edema manifested by worsening of acoustic and self-perceptual voice measures and changes in ratings of laryngeal appearance. STUDY DESIGN: Prospective Cohort study. METHODS: Acoustic and self-perceptual voice measures that were potentially sensitive to laryngeal edema were collected from ten cycling instructors (Mean age: 31 ± 6.14 years, 3M and 7F) before and after instruction of a typical 45-minute cycling class. Two laryngologists then rated pairs of laryngeal exams from five instructors (Mean age: 30 ± 6.22 years, 1M and 4F) on the measure of vocal fold edema using a 10-inch Visual Analogue Scale. Paired t-test comparisons were completed on normalized data to compare pre- and postinstruction. RESULTS: Majority of acoustic and self-perceptual measures significantly worsened following cycling instruction but the magnitude of change in these measures were small. In terms of laryngeal appearance, no measurable change in vocal fold edema was observed at both time points. CONCLUSION: The vocal demand response to a single cycling class may be insufficient to cause significant vocal fold edema in our cycling instructors. Future research is required to determine the effects of repeated cycling instruction.

Montgomery's Aperture: An External Anatomic Landmark for Surgical Identification of the Anterior Commissure.

OBJECTIVES: This study evaluates the consistency of palpable identification of an external landmark for the anterior commissure (AC), termed Montgomery's aperture (MA), in cadaveric and surgical settings. METHODS: Part 1: In human cadaveric larynges, palpation of the external laryngeal framework was used to identify MA by three blinded otolaryngologists. The vertical height (VH) of the thyroid cartilage and distance from MA to the inferior border of the thyroid cartilage were measured, larynges were bisected, and the AC was identified and measured. Surface anatomy was demonstrated visually using 3D imaging. Part 2: Retrospectively collected case series used palpation of MA in thyroplasty type 1 (TT1) and compared the result to ½ VH. RESULTS: Part 1: MA was identified in seven cadavers by three surgeons. In four of seven MA was palpated at the location of AC. The average difference between the AC and MA was -0.95 ± 0.96 mm. The average difference between AC and ½VH was 0.08 ± 0.72 mm. Part 2: In 49 patients (57% females) who underwent TT1, MA correlated within ½VH in 67% of cases. MA was inferior to ½VH in 27% of cases, on average 1.08 mm ± 0.51 mm below ½VH. MA was not palpable in 6% (3 of 49) of patients. CONCLUSION: We define the MA as the external indentation or flattening of the thyroid cartilage located within 1 millimeter inferior or at ½ VH of the thyroid cartilage. MA is a reliable, reproducible, palpable landmark for the anterior commissure. It serves as an important landmark that can be used in laryngoplastic surgery in which accurate prediction of the glottis is important.

Computational Modeling of Voice Production Using Excised Canine Larynx.

A combined experimental-numerical work was conducted to comprehensively validate a subject-specific continuum model of voice production in larynx using excised canine laryngeal experiments. The computational model is a coupling of the Navier-Stokes equations for glottal flow dynamics and a finite element model of vocal fold dynamics. The numerical simulations employed a cover-body vocal fold structure with the geometry reconstructed from magnetic resonance imaging scans and the material properties determined through an optimization-based inverse process of experimental indentation measurement. The results showed that the simulations predicted key features of the dynamics observed in the experiments, including the skewing of the glottal flow waveform, mucosal wave propagation, continuous increase of the divergent angle and intraglottal swirl strength during glottal closing, and flow recirculation between glottal jet and vocal fold. The simulations also predicted the increase of the divergent angle, glottal jet speed, and intraglottal flow swirl strength with the subglottal pressure, same as in the experiments. Quantitatively, the simulations over-predicted the frequency and jet speed and under-predicted the flow rate and divergent angle for the larynx under study. The limitations of the model and their implications were discussed.

Predicting critical closing pressure in children with obstructive sleep apnea using fluid-structure interaction.

Surgical treatment of obstructive sleep apnea (OSA) in children requires knowledge of upper airway dynamics, including the closing pressure (Pcrit), a measure of airway collapsibility. We applied a flow-structure interaction (FSI) computational model to estimate Pcrit in patient-specific upper airway models obtained from magnetic resonance imaging (MRI) scans. We sought to examine the agreement between measured and estimated Pcrit from FSI models in children with Down syndrome. We hypothesized that the estimated Pcrit would accurately reflect measured Pcrit during sleep and therefore reflect the severity of OSA as measured by the obstructive apnea-hypopnea index (AHI). All participants (n = 41) underwent polysomnography and sedated sleep MRI scans. We used Bland-Altman plots to examine the agreement between measured and estimated Pcrit. We determined associations between estimated Pcrit and OSA severity, as measured by AHI, using regression models. The agreement between passive and estimated Pcrit showed a fixed bias of -1.31 [confidence interval (CI) = -2.78, 0.15] and a nonsignificant proportional bias. A weaker agreement with active Pcrit was observed. A model including AHI, gender, an interaction term for AHI, and gender and neck circumference explained the largest variation (R2 = 0.61) in the relationship between AHI and estimated Pcrit (P < 0.0001). Overlap between the areas of the airway with the lowest stiffness, and areas of collapse on dynamic MRI, was 77.4 ± 30% for the nasopharyngeal region and 78.6 ± 33% for the retroglossal region. The agreement between measured and estimated Pcrit and the significant association with AHI supports the validity of Pcrit estimates from the FSI model.NEW & NOTEWORTHY We present a noninvasive method for estimating critical closing pressure (Pcrit) using fluid-structure interaction (FSI) simulations and magnetic resonance imaging (MRI) scans in patients with obstructive sleep apnea (OSA). We used patient-specific stiffness measures in our FSI model to account for any individual variability in the elasticity of soft tissues surrounding the upper airway. We validated this model by measuring the degree of agreement between measured and estimated Pcrit.

Association of Social Determinants of Health with Time to Diagnosis and Treatment Outcomes in Idiopathic Subglottic Stenosis.

OBJECTIVES: To examine whether social determinants of health (SDH) factors are associated with time to diagnosis, treatment selection, and time to recurrent surgical intervention in idiopathic subglottic stenosis (iSGS) patients. METHODS: Adult patients with diagnosed iSGS were recruited prospectively (2015-2017) via clinical providers as part of the North American Airway Collaborative (NoAAC) and via an online iSGS support community on Facebook. Patient-specific SDH factors included highest educational attainment (self-reported), median household income (matched from home zip code via U.S. Census data), and number of close friends (self-reported) as a measure of social support. Main outcomes of interest were time to disease diagnosis (years from symptom onset), treatment selection (endoscopic dilation [ED] vs cricotracheal resection [CTR] vs endoscopic resection with adjuvant medical therapy [ERMT]), and time to recurrent surgical intervention (number of days from initial surgical procedure) as a surrogate for disease recurrence. RESULTS: The total 810 participants were 98.5% female, 97.2% Caucasian, and had a median age of 50 years (IQR, 43-58). The cohort had a median household income of $62 307 (IQR, $50 345-$79 773), a median of 7 close friends (IQR, 4-10), and 64.7% of patients completed college or graduate school. Education, income, and number of friends were not associated with time to diagnosis via multivariable linear regression modeling. Univariable multinominal logistic regression demonstrated an association between education and income for selecting ED versus ERMT, but no associations were noted for CTR. No associations were noted for time to recurrent surgical procedure via Kaplan Meier modeling and Cox proportional hazards regression. CONCLUSIONS: Patient education, income, and social support were not associated with time to diagnosis or time to disease recurrence. This suggests additional patient, procedure, or disease-specific factors contribute to the observed variations in iSGS surgical outcomes.

Medialization Laryngoplasty: A Review for Speech-Language Pathologists.

Purpose The purpose of this study is to familiarize speech-language-pathologists with the current state of the science regarding medialization laryngoplasty in the treatment of voice disorders, with emphasis on current evidence-based practice, voice outcomes, and future directions for research. Method A literature review was performed in PubMed and Embase using the keywords vocal fold/cord and laryngoplasty, thyroplasty, augmentation, or laryngeal framework. Articles published between 2010 and 2020 were reviewed for data about clinical applications, technical approach, voice-related outcomes, and basic science or clinical innovations with the potential to improve patient care. A synthesis of data was performed from articles meeting the outlined search criteria. Conclusions As key members in the multidisciplinary care of voice disorders, speech-language pathologists need to be informed of current research in medialization laryngoplasty, a procedure commonly used for patients with glottic insufficiency. Advances in anesthetic technique, office-based procedures, and the development of materials with increased bio-tolerability over the past decade have led to innovations in treatment and improved patient outcomes. Recent applications of computational and bioengineering approaches have the potential to provide new directions in the refinement of currently available techniques and the improvement of patient-based treatment outcomes.

Medial Surface Dynamics as a Function of Subglottal Pressure in a Canine Larynx Model.

During vocal fold vibration, there may be a mucosal wave in the superior-inferior (vertical) direction, resulting in a convergent shape during opening and a divergent shape during closing. Most of our understanding of the converging/diverging shape of the glottis has come from studies in a hemilarynx model. Previous work has shown that vibratory patterns in the full excised larynx are different than the hemilarynx. This study characterized the dynamics of the medial glottal wall geometry during vibrations in the full excised canine larynx model. Using particle image velocimetry, the intraglottal geometry was measured at the midmembranous coronal plane in an excised canine larynx model. Measurements of the glottal area were taken simultaneously using high-speed imaging. The results show that skewing of the glottal area waveform occurs without the presence of a vocal tract and that the phase-lag of the superior edge relative to the inferior edge is smaller than reported and depends on the subglottal pressure. In addition, it shows that the glottal divergence angle during closing is proportional to the magnitude of the acoustic intensity and the intraglottal negative pressure. This preliminary data suggests that more studies are needed to determine the important mechanisms determining the relationship between intraglottal flow, intraglottal geometry, and acoustics.

Predicting No Show in Voice therapy: Avoiding the Missed Appointment Cycle.

INTRODUCTION: Voice therapy plays a critical role in the treatment of voice disorders. Despite positive outcomes in patients who attend voice therapy, otolaryngologists, and speech-language pathologists continue to struggle with patient compliance. Previous studies evaluating the multidisciplinary clinic model have shown better completion, VHI-10 scores, and fewer cancelation and no-shows (NS). We sought to review our own patient experience to better identify factors that predict NS rates in voice therapy. METHODS: A retrospective chart review of patients at a tertiary medical center were included if they had a scheduled appointment during a 6-month period that was cancelled or a NS. Charts were reviewed for age, gender, race, diagnosis, number of sessions attended, reason for discharge, and attending physician. NS percentage is calculated as a ratio of number cancellations to total number sessions scheduled. A multivariable general linear model was used to examine the association between NS and the listed covariates. FINDINGS: The study included 146 patients mean (SD) age 52.7 (16.6), where 62% were female and 72.6% were white. There is evidence that not being seen in a multidisciplinary clinic is significantly associated with NS rates in voice therapy (χ2 = 4.09, P = 0.0431). There is also evidence that non-white race is significantly associated with NS rates in voice therapy (χ2 = 11.76, P = 0.0006). CONCLUSIONS: Data presented in this study further support the use of a multidisciplinary model to improve NS rates in voice therapy. The relationship between nonwhite patients and lower NS suggests another determining factor in nonadherence to voice therapy.

Quantification of the Intraglottal Pressure Induced by Flow Separation Vortices Using Large Eddy Simulation.

The greatest rate of change in the glottal flow rate during phonation is a rapid decrease that occurs during the latter part of the glottal closing. Previous works showed that intraglottal flow separation vortices form in a divergent glottis, produce negative gauge pressures (below atmospheric) during closing. It is hypothesized here that flow separation vortices contribute to the rapid closing mechanism of the true vocal folds during phonation. Four idealized static models (M5) of the human larynx were investigated using large eddy simulation: 2 models featured parallel folds that did not enable flow separation in the glottis and 2 models involved a divergent glottis. The influence of the ventricular gap (narrow/wide) is evaluated. An unsteady pressure inlet representing a voicing cycle was applied to the sub-glottal region to mimic the time-varying glottal flow. Intraglottal vortex structures formed downstream of the separation point in a divergent glottis. Their existence caused a higher closing force that was applied onto the vocal folds. A narrow ventricular gap strengthens this effect. Strength of the intraglottal vortices increased with the maximum flow declination rate. Therefore, a more divergent shape of the glottis during glottal closing will be one of the main contributors to the voice quality.

Effects of False Vocal Folds on Intraglottal Velocity Fields.

Previous models have theorized that, during phonation, skewing of the glottal waveform (which is correlated with acoustic intensity) occurred because of inertance of the vocal tract. Later, we reported that skewing of the flow rate waveform can occur without the presence of a vocal tract in an excised canine larynx. We hypothesized that in the absence of a vocal tract, the skewing formed when dynamic pressures acted on the glottal wall during the closing phase; such pressures were greatly affected by formation of intraglottal vortices. In this study, we aim to identify how changes in false vocal folds constriction can affect the acoustics and intraglottal flow dynamics. The intraglottal flow measurements were made using particle image velocimetry in an excised canine larynx where a vocal tract model was placed above the larynx and the constriction between the false vocal folds was varied. Our results show that for similar values of subglottal pressures, the skewing of the glottal waveform, strength of the intraglottal vortices, and acoustic energy increased as the constriction between the false vocal folds was increased. These preliminary findings suggest that acoustic intensity during phonation can be increased by the addition of a vocal tract with false fold constriction.