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Cold-steel has served as the gold standard modality of phonosurgery for most of its history. Surgical laser technology has revolutionized this field with its wide use of applications. Additional modalities have also been introduced such as coagulative lasers, photodynamic therapy, and cryotherapy. This review will compare the surgical modalities of cold steel, surgical lasers, phototherapy and cryotherapy. The mechanism of action, tissue effects and typical uses will be addressed for each modality.

Background: Gastric adenocarcinoma is a common neoplasm worldwide. Patients with completely resected disease often have locoregional recurrence, and adjuvant chemotherapy has failed to reduce the common occurrence of metastases. Protein kinase C (PKC) is thought to be important in tumor cell invasion, but its relationship to gastric cancer cell invasion, and thus metastases, remains unexplored. We recently identified and established invasive and noninvasive human gastric adenocarcinoma cell lines, which can now be used to test agents for inhibition of tumor cell invasion by inhibition of PKC activity. Purpose: The objectives were (a) to test threo-dihydrosphingosine (SPC100221), a specific inhibitor of PKC at its regulatory site, and staurosporine, a potent but nonspecific inhibitor of PKC at its catalytic site, for their effects on gastric cancer cell invasion in vitro and (b) to determine whether the expression of PKC isoforms can distinguish invasive from noninvasive gastric cancer cells. Methods: Gastric cancer cell invasion through Matrigel-coated Nuclepore filters in the Boyden chamber assay was analyzed in the presence of graded concentrations of SPC100221 and staurosporine. The invasive SK-GT-1 and SK-GT-5 cell lines and the noninvasive SK-GT-2 and SK-GT-4 cell lines were used. PKC isoform expression was determined by reverse transcription of messenger RNAs to complementary DNA and subsequent amplification by the polymerase chain reaction. Results: The effects of staurosporine and SPC100221 on tumor cell invasion were tested at drug concentrations that did not inhibit cell proliferation, as evidenced by [H.sup.3]thymidine uptake. Staurosporine and SPC100221 at subtoxic doses inhibited human gastric cancer cell invasion by 50% at 5 x [10.sup.-9] M and 2 x [10.sup.-7] M, respectively. The expression of PKC[beta] was observed in the invasive but not the noninvasive gastric cancer cells. Both types of cells, however, expressed the PKC[alpha] and PKC[gamma] isoforms. Conclusions: Gastric cancer cell invasion can be inhibited by PKC inhibitors, and expression of PKC[beta] may be a marker of invasiveness in gastric cancer. Implications: PKC appears to represent a new target for inhibition of gastric cancer cell invasion, and SPC100221, in view of its PKC specificity, may provide a model for future drug development in this area. Moreover, PKC[beta] may have a fundamental role in the development of invasive potential in gastric cancer. [J Natl Cancer Inst 85:402-407, 1993]

Objective: To investigate the value of diffusion tensor imaging (DTI) in the evaluation of vocal fold tissue microstructure after recurrent laryngeal nerve (RLN) injury.Methods: Six canines were divided into 2 groups: a unilateral vocal fold paralysis group (n = 4) and a control group (n =2). The RLN was cut in the unilateral vocal fold paralysis group, and no intervention was applied in the control group. After 4 months, the canines’ larynges were removed and placed in a small animal magnetic resonance imaging (MRI) system (9.4T BioSpec MRI; Bruker, Germany). After scanning, the vocal folds were isolated, sectioned, and stained. The slides were then analyzed for the cross-sectional area and muscle fiber density through feature extraction technology. Pearson correlation analysis was performed on the DTI scan and histological section extraction results.Results: In the vocal fold muscle layer, the fractional anisotropy (FA) of the unilateral RLN injury group was higher than that of the control group, and the Tensor Trace was lower than that of the control group. This difference was statistically significant, P< .05. In the lamina propria, the FA of the unilateral RLN injury group was lower than that of the control group, P> .05, and the Tensor Trace was lower than that of the control group, P< .05. The muscle fiber cross-sectional area of the RLN injury group was significantly smaller than the control group with statistical significance, P< .05, and the density of muscle fibers was lower, P< .05. The correlation coefficient between FA and the cross-sectional area was −0.838, P= .002, and .726; P= .017 between Tensor Trace and the cross-sectional area.Conclusion: Diffusion tensor imaging is an effective method to assess the changes in the microstructure of atrophic vocal fold muscle tissue after RLN injury.

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.

Purpose: Signal typing has been used to categorize healthy and disordered voices; however, human voices are likely comprised of differing proportions of periodic type 1 elements, type 2 elements that are periodic with modulations, aperiodic type 3 elements, and stochastic type 4 elements. A novel diffusive chaos method is presented to detect the distribution of voice types within a signal with the goal of providing an objective and clinically useful tool for evaluating the voice. It was predicted that continuous calculation of the diffusive chaos parameter throughout the voice sample would allow for construction of comprehensive voice type component profiles (VTCP).Methods: One hundred thirty-five voice samples of sustained /a/ vowels were randomly selected from the Disordered Voice Database Model 4337. All samples were classified according to the voice type paradigm using spectrogram analysis, yielding 34 type 1, 35 type 2, 42 type 3, and 24 type 4 voice samples. All samples were then analyzed using the diffusive chaos method, and VTCPs were generated to show the distribution of the 4 voice type components (VTC).Results: The proportions of VTC1varied significantly between the majority of the traditional voice types (P< .001). Three of the 4 VTCs of type 3 voices were significantly different from the VTCs of type 4 voices (P< .001). These results were compared to calculations of spectrum convergence ratio, which did not vary significantly between voice types 1 and 2 or 2 and 3.Conclusion: The diffusive chaos method demonstrates proficiency in generating comprehensive VTCPs for disordered voices with varying severity. In contrast to acoustic parameters that provide a single measure of disorder, VTCPs can be used to detect subtler changes by observing variations in each VTC over time. This method also provides the advantage of quantifying stochastic noise components that are due to breathiness in the voice.

Objectives: The aims of this study were to compare nondysphonic adult and pediatric voices using linear and nonlinear acoustic parameters and to evaluate the ability of adult spectrum convergence ratio (SCR) and rate of divergence (ROD) reference values to correctly identify a pediatric voice type as periodic or aperiodic.Methods: Twenty adult and 36 pediatric nondysphonic voice samples were collected and analyzed using linear and nonlinear acoustic parameters. Absence of voice disorder was confirmed using perceptual acoustic and spectral analysis. Mean values for jitter, shimmer, SCR, and ROD were compared between adults and children, across specific age groups, and within genders. Using adult reference values for SCR and ROD, samples were classified as primarily periodic or aperiodic and typed using spectral analysis. Rates of accurate typing were also compared between subject groups.Results: Overall, jitter and shimmer were similar among the adult and pediatric age groups. ROD was significantly different among the 3 pediatric and 1 adult group; the pediatric age groups were similar to one another. Adult SCR was also significantly different from all of the pediatric age groups. In adult men, ROD and SCR were significantly different from all of the pediatric age groups; the pediatric age groups were similar to one another. In female subjects, ROD was significantly different among all age groups. The ROD and SCR reference values were significantly better at categorizing adult voice types compared with pediatric voice types.Conclusions: In healthy subjects, SCR and ROD have discriminatory power for identifying adult versus pediatric voices, while jitter and shimmer cannot differentiate between the 2 groups. However, age- and gender-specific pediatric reference values must be determined to accurately classify voice types using SCR and ROD.

Objective: The aim of this study was to investigate the physiological activity of intrinsic laryngeal muscle under different functional states of larynx by measuring the normal laryngeal electromyography parameters.Methods: Laryngeal electromyography (EMG) was performed in 112 patients with unilateral vocal cord movement disorder. The duration and amplitude of the motor unit potential (MUP) of the thyroarytenoid muscle (TA), posterior cricoarytenoid muscle (PCA), and cricothyroid muscle (CT) were measured when patients were asked to make a deep inspiration and phonate /i/. The normal side of the patients’ vocal chords was used as the research object.Results: (1) The motor unit potential of TA, CT, and PCA were measured when inspiration and phonating /i/. Waveforms were normal. (2) There were significant differences in duration of TA between inspiration and phonating /i/ in comfortable tone. (3) When comparing the duration and amplitude of any 2 of TA, CT, and PCA during inspiration and phonating /i/, there were significant differences in duration between CT and PCA when phonating /i/ only. There were no significant differences in any other comparisons.Conclusions: Under either deep inspiration or pronunciation, the TA, CT, and PCA muscles were activated. The TA may play a major role in phonating. The PCA may play a major role in the action of deep inspiration.

Purpose: The overall aim of this study was to apply local intrinsic dimension (Di) estimation to quantify high-dimensional, disordered voice and discriminate between the 4 types of voice signals. It was predicted that continuous Dianalysis throughout the entire time-series would generate comprehensive descriptions of voice signal components, called voice type component profiles(VTCP), that effectively distinguish between the 4 voice types.Method: One hundred thirty-five voice recording samples of the sustained vowel /a/ were obtained from the Disordered Voice Database Model 4337 and spectrographically classified into the voice type paradigm. The Diand correlation dimension (D2) were then used to objectively analyze the voice samples and compared based on voice type differentiation efficacy.Results: The D2exhibited limited effectiveness in distinguishing between the 4 voice type signals. For Dianalysis, significant differences were primarily observed when comparing voice type component 1 (VTC1) and 4 (VTC4) across the 4 voice type signals (P< .001). The 4 voice type components (VTCs) significantly differentiated between low-dimensional, type 3 and high-dimensional, type 4 signals (P< .001).Conclusions: The Didemonstrated improvements over D2in 2 distinct manners: enhanced resolution at high data dimensions and comprehensive description of voice signal elements.

Objective: To evaluate a cost-effective modified rigid laryngoscopy setup with a portable light source and high-resolution commercially available digital camera for use in smaller otolaryngology and family practice clinics.Methods: The modified setup was used to obtain images of the larynx using both a traditional light source and a portable light source. Varying shutter speeds and ISOs were evaluated, and the optimal settings were determined for the modified setup.Results: Picture quality was adequate, and the portable light source was bright enough. ISO from 640 to 1600 with shutter speeds ranging from 1/60 to 1/160 are ideal under the normal light source, while it is better to set the ISO between 4000 and 10 000 with shutter speeds from 1/60 to 1/100 under the portable light source. Picture quality was adequate with a resolution of 2768 pixels × 1848 pixels with 350 dpi × 350 dpi.Conclusions: Results show that the modified setup obtains images of adequate quality for use in the clinic. Additionally, since the larynx requires the most illumination for endoscopic imaging, a similar setup would work for imaging the ear and nose. This setup may make laryngoscopic exams more accessible to patients at smaller laryngoscopy clinics or family practice providers.

Objectives: The objective of this study was to create a 3D printed airway model simulating the size and mechanical properties of various age groups for foreign body removal training.Methods: Three-dimensional printing technology was used to print the anatomically correct airway from rubber-like translucent material, simulating the mechanical properties of human airway tissue. The model’s effectiveness in trainee education was evaluated by otolaryngology residents with varying levels of experience. As part of an Airway Emergencies course, a rigid bronchoscopy procedure was performed on the 3D printed model as well as a porcine model. The participants completed surveys comparing the validity of the 2 models and the effectiveness of the overall training experience.Results: The 3D printed model, which is accurate in terms of anatomy and mechanical properties, was found to be comparable to a porcine model in regards to participant satisfaction as well as face validity.Conclusions: The 3D printed airway model is able to be accurately scaled to various sizes and simulate the mechanical properties of the desired age group. The 3D printed model provides an excellent alternative to animal models in terms of practicality, logistics of use, and anatomical accuracy.

Objectives/Hypothesis: To evaluate the spatiotemporal correlation of vocal fold vibration using eigenmode analysis before and after polyp removal and explore the potential clinical relevance of spatiotemporal analysis of correlation length and entropy as quantitative voice parameters. We hypothesized that increased order in the vibrating signal after surgical intervention would decrease the eigenmode-based entropy and increase correlation length.Study Design: Prospective case series.Methods: Forty subjects (23 males, 17 females) with unilateral (n = 24) or bilateral (n = 16) polyps underwent polyp removal. High-speed videoendoscopy was performed preoperatively and 2 weeks postoperatively. Spatiotemporal analysis was performed to determine entropy, quantification of signal disorder, correlation length, size, and spatially ordered structure of vocal fold vibration in comparison to full spatial consistency. The signal analyzed consists of the vibratory pattern in space and time derived from the high-speed video glottal area contour.Results: Entropy decreased (Z = −3.871, P< .001) and correlation length increased (t= −8.913, P< .001) following polyp excision. The intraclass correlation coefficients (ICC) for correlation length and entropy were 0.84 and 0.93.Conclusion: Correlation length and entropy are sensitive to mass lesions. These parameters could potentially be used to augment subjective visualization after polyp excision when evaluating procedural efficacy.

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.

Abstract: UTL-5b is an anti-inflammatory and anti-arthritic small-molecule tumor necrosis factor-alpha inhibitor and a structural analogue of the anti-arthritic drug, leflunomide. Leflunomide is known to be metabolized to teriflunomide, but the metabolites of UTL-5b have not been reported. The objective of this study was to investigate whether UTL-5b has a similar metabolic behavior as leflunomide. Preliminary studies showed that when exposed to microsomes in vitro with or without NADPH, UTL-5b disappeared within 30 min. To further investigate the microsomal metabolism, liquid chromatography-ultraviolet (LC-UV) and LC/tandem mass spectrometry (LC–MS/MS) were employed to, respectively, monitor the microsomal metabolites and identify the structure of the metabolites using LC-full scan MS and LC combined with multiple-ion monitoring MS. Fragmentation determination was analyzed by two types of scans: product ion scans and precursor ion scan. The in vitro microsomal treatment of UTL-5b resulted in two major metabolites: 5-methylisoxazole-3-carboxylic acid and 2-chloroaniline. Thus, the in vitro metabolic behavior of UTL-5b appears to be different from that of leflunomide in that the isoxazole ring is cleaved.

For understanding the phonatory process in human voice production, physical as well as numerical models have been suggested. Material properties within these models are crucial for achieving vocal fold dynamics being close to in vivo human laryngeal dynamics. Hence, different approaches have been suggested to gain insight into human laryngeal tissue, evaluate clinical treatment, as well as to analyze and verify parameters within synthetically built vocal folds. Purpose of Review: The authors want to give an overview of approaches on receiving material parameters being important in voice research. For the different devices and methods being applied for different set-ups, we will present the functionality and applicability. Hence, for future work, this review shall give an indication, what kind of measurement techniques are suitable for the intended study, advantages or disadvantages of the approaches, and what parameters can be obtained from them. Recent Findings: For in vivo experiments, Color Doppler Imaging was found to be suitable for receiving vocal fold stiffness properties. Applying rheological measurements, the elastic modulus and the dynamic viscosity can be determined. In combination with histological analysis it is possible to objectively evaluate clinical treatment. Optical Coherence Tomography enabled to detect tissue boundaries for in vitro vocal folds. A pipette aspiration setup allowed to identifying spacially resolved mechanical properties of synthetic vocal folds. Numerical biomechanical models like finite element models have shown to be suitable to identify isotropic elastic material parameters

Objectives:In acoustic voice analysis, the fact that reproducible methods of sample selection have not been defined impedes research study generalizability and clinical assessment of treatment efficacy. Because perturbation results differ along a single signal, this study sought to establish objective methods of sample selection by use of a moving window to determine the most stable regions of phonation.Methods:Voice signals obtained from 21 patients affected by laryngeal conditions associated with Parkinson's disease were analyzed to study jitter, shimmer, signal-to-noise ratio, and correlation dimension parameters when various sample selection procedures were used. Objectively selected voice samples were chosen based upon 5%, 10%, and 20% variance from a signal's minimum perturbation value. The stability of these samples, defined by the standard deviations of the acoustic measurements, was compared to the stability of unselected samples and subjectively selected samples.Results:A significant decrease in standard deviation values of acoustic parameters was found in comparing the objectively selected samples (particularly those selected with 5% and 10% variance) to the subjectively selected and unselected samples.Conclusions:These results suggest that the development of an objective sample selection method may have significant effects on the stability and reliability of acoustic voice measurements.

Objectives:We evaluated the efficacy of the titanium vocal fold medializing implant (TVFMI) for the treatment of unilateral vocal fold paralysis (UVFP) on the basis of acoustic, aerodynamic, and mucosal wave measurements in an excised larynx setup.Methods:Measurements were recorded on 8 excised canine larynges with simulated UVFP before and after medialization with a TVFMI.Results:The phonation threshold flow (p < 0.001) and phonation threshold power (p = 0.008) decreased significantly after medialization. The phonation threshold pressure also decreased, but this difference was not significant (p = 0.081). Jitter (p = 0.005) and shimmer (p = 0.034) decreased significantly after medialization. The signal-to-noise ratio increased significantly (p = 0.05). Differences in mucosal wave characteristics were discernible but not significant. The phase difference between the normal and paralyzed vocal folds (p = 0.15) and the amplitude of the paralyzed vocal fold (p = 0.78) decreased. The glottal gap decreased significantly (p = 0.004).Conclusions:The TVFMI was effective in achieving vocal fold medialization, improving vocal aerodynamic and acoustic characteristics of phonation significantly and mucosal wave characteristics discernibly. This study provides objective, quantitative support for the use of the TVFMI in improving vocal function in patients with UVFP.

Objectives Signal typing is central to the understanding of vocal fold vibratory patterns. Digital kymography (DKG) allows the direct observation of vocal fold vibratory patterns, and therefore, using DKG for vibratory signal typing may provide a useful complement to traditional signal typing techniques.Methods Video data collected from 20 larynges excised from mongrel dogs were observed with DKG in order to find examples of type 1 (nearly periodic), type 2 (subharmonic), and type 3 (aperiodic) vibratory patterns. The time series, frequency spectra, and correlation dimensions were calculated for each signal type.Results The type 1 pattern showed a periodic time series of glottal edges and a discrete frequency spectrum. The type 2 vibratory pattern displayed a time series of alternating high- and low-amplitude waves and a frequency spectrum that included a subharmonic (F0/2) frequency component. Regular and symmetric vibratory patterns were observed in the type 1 and type 2 patterns. The type 3 vibratory pattern was characterized by an aperiodic time series of glottal edges, a broadband frequency spectrum, and irregular and asymmetric vibratory patterns. The correlation dimension estimates increased from type 1 to type 2 to type 3.Conclusions Imaging with DKG demonstrated an ability to assign a signal type to various laryngeal vibrations. Signal typing techniques utilizing direct observation of the vocal folds could be useful in determining valid methods for the analysis of vocal fold vibrations.

Objectives:The minimum airflow necessary to initiate stable vocal fold vibration — Phonation threshold flow (PTF) — May increase as exposure to dry air increases. A critical period of dehydration may exist after which phonation can no longer be initiated.Methods:We collected PTF data for 11 excised canine larynges mounted on a bench apparatus. Trials consisted of cycles of 10 seconds of phonation followed by 3 seconds of rest. During the experimental trials, subglottal flow of comparatively dry air was increased until phonation was initiated, and phonation was sustained for the remainder of the 10-second period. The subglottal flow was then decreased until phonation ceased. No saline solution was applied during the dehydration trials. During the control trials, subglottal airflow was humidified and saline solution was applied frequently to the vocal folds.Results:The PTF increased as exposure to dry air increased during the experimental trials (p = 0.010); this relationship was not statistically significant in control trials. A point existed after which phonation could not be initiated.Conclusions:Knowledge of the effect of exposure to dry air on PTF could be useful in the clinical assessment and prevention of dehydration. Further exploration of this relationship in vivo could be used to evaluate the effectiveness of current hydration therapies and provide theoretical support for the development of new ones.

Objectives:Our aim was to estimate aerodynamic parameters of laryngeal resistance (Rl) and aerodynamic power indirectly from a subglottal pressure (Ps) data trace obtained with the airflow redirection system.Methods:During airflow interruption, the airflow redirection tank fills capacitively with pressure until it reaches the subject's Ps. Therefore, a time constant, τ, can be extracted from the data trace and used to calculate Rl. The validity of applying this method to the estimation of RL was demonstrated with a computer model. Estimations were made for values of 10, 20, 30, 40, and 50 cm H2O per liter per second (L/s). Twenty subjects performed 10 trials on the experimental system designed to measure Ps. The values of RL and aerodynamic power were then calculated.Results:The computer model simulation yielded a maximum measurement error of 3.00% and a mean error of 1.78%. In human subject testing, the mean ± SD laryngeal resistance was 22.61 ± 8.65 cm H2O per L/s, the mean Ps was 6.91 ± 1.94 cm H2O, and the mean aerodynamic power was 0.247 ± 0.170 kPa × (L/s).Conclusions:The proposed method of data analysis enables a clinician to estimate Rl and aerodynamic power from a single experimental trial designed to measure Ps. This technique provides the clinician with an aerodynamic function report that can be used to analyze patient health and treatment efficacy.

Dielectric capping layer and electrode alloying approaches for tuning the effective work function and effective oxide thickness of metal oxide semiconductor transistors are compared. TaMgC and MoAlN electrodes are compared to MgO and Al2O3 capping layers for n-type and p-type transistors respectively. Results indicate that by incorporating the Mg or Al into the gate electrode instead of into the dielectric capping layer reductions in threshold voltage can be achieved, but with the added benefit of an effective oxide thickness reduction. SIMS results suggest that the threshold voltage shift is likely caused by the inward diffusion of Mg or Al though the gate dielectric towards the bottom interface layer. The limitations of each approach for work function engineering are discussed.

Objective/Hypothesis:Vocal fold vibration is associated with four distinct vibratory patterns: those of the right‐upper, right‐lower, left‐upper, and left‐lower vocal fold lips. The purpose of this study was to propose a least squares method to quantify the vibratory properties of each of the four vocal fold lips via videokymography (VKG).

Objectives/Hypothesis:In this study, we examined the hypothesis that the minimum flow required for phonation onset, the onset phonation threshold flow (PTF), is greater than the minimum flow to sustain phonation, the offset PTF. We also explored the hypothesis that the ratio of these two (PTF offset divided by PTF onset) falls within [0.707, 1.0].

Objectives:This study proposes the use of a new parameter of vocal aerodynamics, phonation threshold flow (PTF). The sensitivities of the PTF and the phonation threshold pressure (PTP) were quantitatively compared to the percent of vocal fold elongation from physiologic length.Methods:Ten excised canine larynges were mounted on a bench apparatus capable of controlling vocal fold elongation. Subglottal airflow was gradually increased until the onset of phonation. Elongation of the vocal folds was varied from +0% (physiologic length) to +15%, and the PTF and PTP were measured.Results:The mean PTFs at physiologic vocal fold length ranged from 101 to 217 mL/s. No statistically significant relationship was found to exist between the size of the larynx and the measured PTF values (p = .404). The average percent change of PTF compared to the magnitude of elongation was found to be statistically significant (p < .001). The data indicated that the PTF was proportional to the percent of vocal fold elongation.Conclusions:The PTF was positively correlated with vocal fold elongation and the PTP for small magnitudes of elongation. The results suggest that the PTF may be indicative of the biomechanical properties of the vocal folds, thus providing a possibly valuable tool in the clinical evaluation of laryngeal function.

Hypothesis:Vocal fold vibration may physically raise intravascular pressure to levels high enough to damage capillaries and result in leakage of erythrocytes. This type of injury is commonly seen in benign vocal fold lesions and is not well explained.

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Objective:To investigate the effects of caveolin‐1 on the growth of laryngeal squamous cell cancer HEp2 cell line in vitro and in vivo.

Objectives/Hypothesis:This experiment studied a new aerodynamic parameter, phonation threshold flow, along with phonation threshold pressure, by varying prephonatory glottal width in canine larynges ex vivo. Goals were to examine phonation threshold flow as a measurable parameter sensitive to physiologic changes in the vocal folds and compare the relative sensitivities of phonation threshold flow and phonation threshold pressure.

Subglottal pressure (SGP) is a valuable parameter in the research and clinical assessment of laryngeal function. The lungs serve as a constant pressure source during sustained phonation, and that pressure, SGP, can be used to determine the efficiency with which the larynx converts aerodynamic power to acoustic power. As the larynx serves as an aerodynamic transducer, the vocal efficiency (Ve) coefficient, defined as acoustic power (dB) divided by aerodynamic power (SGP × glottal airflow) has been shown to reliably reflect vocal health. However, current SGP measurement techniques are hesitantly used because of either an invasive nature or the requirement of intensive patient training. This study tests a novel device that has been designed to noninvasively estimate SGP through mechanical airflow redirection, producing a numeric output on completion of the trial, which lasts only a few seconds. The novelty of this design lies in the ease of use for both the patient and the clinician. Multiple mechanical airflow redirections occlude the airway for only 135 ms, which is predicted to limit the effect of confounding laryngeal reflexes that may occur during the trials. Additionally, the airflow redirection into a retention device allows for the pneumatic in‐trial comparison of the estimated SGP with the pressure achieved by the patient, providing a numeric output to the clinician on completion.

Objective:In recent years, a growing body of evidence has been reported that a tumor clone is organized as a hierarchy that originates from rare stem cells. CD133, a cell surface antigen, was identified as a stem cell maker for human leukemia, brain tumors, and prostate cancer. The purpose of this study was to detect the expression of CD133, a putative marker of cancer stem cells in the Hep‐2 cell line, and isolate CD133 positive cells to observe their proliferation and differentiation ability in vitro.

Objectives:Nearly one third of patients with idiopathic Parkinson's disease (IPD) cite dysphonia, characterized subjectively as causing a harsh and breathy voice, as their most debilitating deficit. Medical or behavioral treatments may lead to voice improvement. The purpose of this study was 1) to determine whether vocal fold injection of Cymetra (micronized form of collagen, elastin, proteoglycans; Lifecell Co.) is associated with changes in dysphonic voice characteristics in subjects with IPD, as judged perceptually using a standard instrument Consensus Auditory‐Perceptual Evaluation of Voice (CAPE‐V), and (2) which acoustic and aerodynamic measurements of voice are most reflective of any observed perceptual changes in voice.

Objective/Hypothesis:Subglottal pressure (SGP) measurements are often used to assess laryngeal function; however, current methods to measure SGP are invasive or do not estimate SGP during phonation. The purpose of this study was to devise a noninvasive technique to estimate SGP without interrupting phonation.

Aerodynamic parameters provide objective and quantitative measures of laryngeal functional status. Jiang et al previously introduced an airflow interruption technique that can determine mean phonatory airflow, subglottic pressure, and phonation threshold pressure simultaneously and noninvasively. In this study, we performed receiver operating characteristic (ROC) analysis to evaluate this airflow interruption apparatus for voice profile analysis in subjects with laryngeal polyps or nodules or with Parkinson's disease. Patients with polyps (n = 14), nodules (n = 9), and Parkinson's disease (n = 12) were evaluated with the airflow interruption apparatus. Normal subjects served as controls. Mean airflow, subglottic pressure, and phonation threshold pressure were determined. Discriminant analysis was used to create linear equations combining all three parameters in order to obtain a new combined parameter. Solutions to the linear equations yielded values for the combined parameter that took into account mean airflow, subglottic pressure, and phonation threshold pressure. Combined parameter values were used as data to generate ROC curves. Laryngeal polyps were distinguished from the normal larynx with a sensitivity of 0.929 and a specificity of 0.933 at the point of maximal efficiency. The area under the ROC curve was 0.977 (Az). Patients with Parkinson's disease were distinguished from normal subjects with a sensitivity of 0.667 and a specificity of 0.909 at the point of maximal efficiency. The area under the ROC curve was 0.7958 (Az). Nodules were able to be distinguished from normal with a sensitivity of 0.889 and a specificity of 1.00. The area under the ROC curve was 0.9565 (Az). Our conclusions are twofold. First, aerodynamic parameters may be combined for simultaneous consideration by the construction of linear equations by means of discriminant analysis. Second, the airflow interruption apparatus, when used for voice function evaluation, has high sensitivity and specificity.

Vocal efficiency is a quantitative measure of the ability of the larynx to convert subglottal power to acoustic power. On the basis of the scant previous literature and clinical intuition, we tested the hypothesis that vocal efficiency, as an indicator of the functional status of the larynx, is abnormally reduced in persons with vocal nodules and polyps. Because the most difficult aspect of obtaining measures of vocal efficiency has been the determination of subglottal pressure, we applied a noninvasive airflow interruption technique for this purpose. Subjects with normal voices (n = 22), vocal polyps (n = 14), and vocal nodules (n = 16) phonated at different intensities into a mask connected by way of piping to a flow meter, a pressure transducer, and an acoustic microphone. Inflation of a balloon-type valve located within the piping provided interruption of phonation. The intraoral pressure plateau occurring during flow interruption was used to estimate subglottal pressure. Subglottal power and acoustic power were determined, and their quotient provided a measure of vocal efficiency. The vocal efficiency in the normal subjects averaged 1.15 × 10−5at 70 dB, 3.17 × 10−5at 75 dB, 7.52 × 10−5at 80 dB, and 1.41 × 10−4at 85 dB. The vocal efficiency in the patients with vocal polyps averaged 3.62 × 10−6at 70 dB, 8.34 × 10−6at 75 dB, 2.10 × 10−5at 80 dB, and 4.26 × 10−5at 85 dB. The vocal efficiency in the patients with vocal nodules averaged 4.32 × 10−6at 70 dB, 1.57 × 10−5at 75 dB, 4.26 × 10−5at 80 dB, and 8.34 × 10−5at 85 dB. As compared to the normal subjects, the patients with laryngeal polyps or vocal nodules had significantly reduced vocal efficiency. These results provide quantitative verification of the clinical impression of inefficient phonation in patients with mass lesions of the vocal folds.

Vocal fold impact stress (force/area) has been implicated as a factor possibly contributing to the formation of nodules and polyps. The force of impact of a moving body is related to its acceleration. Since the mass of the folds is relatively constant, one expects impact force to be directly proportional to acceleration. A measure that reflects the relative displacement of the vocal folds is photoglottography (PGG). The velocity and acceleration of the folds are easily obtained by calculating the first and second derivatives of the PGG displacement waveform. This study, therefore, compared the second derivative of the PGG signal with simultaneously measured impact stress in an excised canine larynx model. Glottal transillumination (PGG) was measured with a subglottic transducer. A miniature force transducer placed in the midline between the vocal folds measured impact stress at the midglottal position. For nine different larynges, there was a positive and linear relationship between the second derivative of PGG and impact stress. The statistically significant results support the hypothesis that the second derivative of PGG may provide a useful noninvasive way to estimate relative vocal fold impact stress.

Chronic laryngitis typically produces symptoms of frequent throat-clearing, soreness, decreased voice quality with use, nonproductive cough, globus sensation, and odynophagia. The endoscopic laryngeal examination usually demonstrates posterior glottic edema, erythema, and increased vascularity and nodularity. There is increasing support for the hypothesis that reflux of acidic gastric contents is often responsible for the symptoms and findings of chronic laryngitis. Prospective trials of acid suppression therapy demonstrate not only efficacy in symptom reduction, but also objective improvement in measurements of voice quality and mucosal erythema. Although traditionally considered the “gold standard” for diagnosis of reflux causing laryngitis, routine esophageal pH recording may result in false negatives in up to 50% of patients. This may confound the diagnosis of chronic laryngitis and delay treatment. Conversely, a positive study during comprehensive therapy may help identify patients who need additional treatment. A single distal probe is probably insufficient for evaluation of a supraesophageal disorder. Current recommendations for double-probe pH study in the evaluation of chronic laryngitis fall into 2 categories: 1) a double-probe pH study is indicated if there is ongoing moderate-to-severe laryngitis despite antireflux precautions and proton pump inhibitor treatment for at least 6 to 12 weeks; and 2) a double-probe pH study is indicated as a baseline measurement before Nissen or Toupet fundoplication. The pH study would also be indicated in patients who have symptoms after fundoplication. There is clearly much more work to be done on the technical issues of obtaining accurate objective data related to laryngeal acidification. In addition, although acid reflux appears to be causative in many cases of chronic laryngitis, further work is indicated to identify reliable testing methods that will predict treatment success.

ObjectivesVocal fold mucosal wave movements are thought to be important in determining voice characteristics and quality. To see these movements, high‐speed cinematography and videostroboscopy have been used clinically; however, these techniques have disadvantages that make them impractical for quantitative measurement of mucosal wave movements. This study explored the feasibility of using line‐scan cameras for mucosal wave analysis.

The effects of exposure to dry air on phonation were measured in an ex vivo model of vocal fold vibration. Excised canine larynges were mounted on an apparatus and made to phonate at a constant subglottal pressure by means of unhumidified airflow. The phonation threshold pressure (FTP), glottal airflow, sound intensity of the acoustic output, and effects on vocal efficiency were also assessed. Student's r-test was performed on the results. In 17 larynges, the average PTP increased from 10.0 cm H2O to 15.0 cm H2O after exposure to dry airflow (p < .001). In addition, the average flow increased from 585 mL/s to 801 mL/s at a constant suprathreshold subglottal pressure (p < .001), and from 323 mL/s to 610 mL/s at the PTP (p < .001). The average acoustic output levels, measured during stable phonation segments, markedly decreased with exposure to the dry airflow, from 91.5 dB to 88.5 dB (p < .001). The average vocal efficiency decreased from 3.63 × 10−4to 7.00 × 10−5(p < .001). No such changes were seen in control larynges phonated with 100% humidified air used for driving the airflow. The results support previously reported modeling and experimental findings that dehydration of the vocal fold generally degrades laryngeal performance.

Phase measures with simultaneously recorded electroglottography (EGG) and photoglottography (PGG) signals have been studied in canine models and found to be sensitive to the effect of recurrent laryngeal nerve (RLN) paralysis on vocal fold vibration. This study examined the usefulness of this type of measure in clinical application. The combined glottographic signals were obtained from 5 men with a diagnosis of unilateral RLN paralysis and 5 age-matched controls. In the patient group, EGG waveforms were found to have a consistent phase delay in relation to PGG. A measure of the overall glottographic phase difference (GPD) was found to significantly distinguish the control group (mean GPD = 0.2371 ms) from the patient group (mean GPD = −0.2765 ms). A validity analysis performed on 19 subjects with or without unilateral RLN paralysis confirmed that the GPD test had a relatively high efficiency (91.7%) in detecting unilateral RLN paralysis in the male population.

To test the effects of different sources of tremor on the voice, tremor was simulated by external rhythmic perturbation of structures at the subglottal, glottal, and supraglottal levels in 10 healthy subjects. The acoustic and airflow signals simultaneously recorded during sustained phonation in the normal and the 3 simulated tremor conditions were analyzed and compared. Voice measures included: fundamental frequency, 2 short-term perturbation measures (jitter and shimmer), and 3 long-term tremor measures (prominence ratios of the spectral peaks of the acoustic frequency contour, acoustic amplitude contour, and airflow contour). Measures of fundamental frequency and percent shimmer were not significantly affected by the simulated tremors. Measures of percent jitter and the amplitudes of the long-term frequency and amplitude modulations were most prominently increased when respiratory drive was perturbed by simulated tremor. Spectral analysis of the acoustic amplitude contour was most useful in distinguishing the 3 sites of simulated tremor.

Head extension with protruded tongue is the position for video-laryngoscopy and simultaneous glottographic recordings including photoglottographic signals. This study investigated the effect of head extension and tongue protrusion on the measures of fundamental frequency, frequency perturbation (jitter), and amplitude perturbation (shimmer). Acoustic signals recorded during sustained vowels were obtained from 49 women and 66 men with no speech or voice disorders in different head-tongue positions. Head extension was associated with increased fundamental frequency and decreased shimmer. In men, head extension did not appear to affect jitter. When the tongue was protruded, head extension tended to lower jitter. For both genders, tongue protrusion was associated with decreased fundamental frequency with head extension. In the men, tongue protrusion tended to increase shimmer when the head was in the neutral position. In the women, tongue protrusion was associated with increased jitter and increased shimmer and was most evident in the head-neutral position. These findings supported a physical linkage hypothesis of the relationship between vocal tract configuration and vocal fold vibration, suggesting that head-tongue position must be taken into account when comparing voice measures.