Acoustic Character Governing Variation in Normal, Benign, and Malignant Voices.

INTRODUCTION: Benign and malignant vocal fold lesions are growths that occur on the vocal folds. However, the treatments for these two types of lesions differ significantly. Therefore, it is imperative to use a multidisciplinary approach to properly recognize suspicious lesions. This study aims to determine the important acoustic characteristics specific to benign and malignant vocal fold lesions. METHODS: The acoustic model of voice quality was utilized to measure various acoustic parameters in 157 participants, including individuals with normal, benign, and malignant conditions. The study comprised 62 female and 95 male participants (43 ± 10 years). Voice samples were collected at the Shanghai Eye, Ear, Nose and Throat Hospital between May 2020 and July 2021.The acoustic variables of the participants were analyzed using Principal Component Analysis to present important acoustic characteristics that are specific to normal vocal folds, benign vocal fold lesions, and malignant vocal fold lesions. The similarities and differences in acoustic factors were also studied for benign conditions including Reinke's edema, polyps, cysts, and leukoplakia. RESULTS: Using the Principal Component Analysis method, the components that accounted for the variation in the data were identified, highlighting acoustic characteristics in the normal, benign, and malignant groups. The analysis indicated that coefficients of variation in root mean square energy were observed solely within the normal group. Coefficients of variation in pitch were found to be significant only in benign voices, while higher formant frequencies and their variability were identified as contributors to the acoustic variance within the malignant group. The presence of formant dispersion as a weighted factor in Principal Component Analysis was exclusively noted in individuals with Reinke's edema. The amplitude ratio between subharmonics and harmonics and its coefficients of variation were evident exclusively in the polyps group. In the case of voices with cysts, both pitch and coefficients of variation for formant dispersion were observed to contribute to variations. Additionally, higher formant frequencies and their coefficients of variation played a role in the acoustic variance among voices of patients with leukoplakia. CONCLUSION: Experimental evidence demonstrates the utility of the Principal Component Analysis method in the identification of vibrational alterations in the acoustic characteristics of voice affected by lesions. Furthermore, the Principal Component Analysis analysis has highlighted underlying acoustic differences between various conditions such as Reinke's edema, polyps, cysts, and leukoplakia. These findings can be used in the future to develop an automated malignant voice analysis algorithm, which will facilitate timely intervention and management of vocal fold conditions.

A Chaotic Approach to Glottal Gap Voice.

OBJECTIVE: Airway glottic insufficiency, or glottal gap, may lead to a breathy voice quality. It is hypothesized that a glottal gap may be a source of nonlinearity in speech production. This study aims to gain a chaotic and acoustic profile of glottal gap voice provided by phonation of excised larynges subjected to the insertion of a metal shim in the posterior glottis. STUDY DESIGN: Nonrandomized quasi-experimental study. METHODS: Posterior glottal gap varied from 0 to 3.5 mm in 0.5 mm intervals. Each treatment was investigated independently in a sample population of eight excised canine larynges. Phonation of the larynges for each treatment was recorded and analyzed for the cepstral peak prominence (CPP), harmonics-to-noise ratio (HNR), and correlation dimension. RESULTS: Kruskal-Wallis rank-sum tests yielded significant differences across shim groups for all parameters. Dunn-Bonferroni post-hoc tests revealed that the control group differed significantly from the 1.5, 2, 2.5, 3, and 3.5 mm groups for all metrics. Moreover, Kendall correlation tests indicated a moderately positive correlation between glottal gap size and correlation dimension, a moderately negative correlation between glottal gap size and CPP and between glottal gap size and the HNR. CONCLUSIONS: Glottic insufficiency provides a source of nonlinearity in phonation. Nonlinear dynamic analysis provides quantitative insight into glottal gap voice. This study encourages future studies to further evaluate the relationship between glottal gap and correlation dimension.

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

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

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

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

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

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

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

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

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

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

Introduction of Voice Type Component (VTC) as an Effective Acoustic Voice Analysis Method in Tele-evaluation.

OBJECTIVE: Telepractice in voice health care and evaluation services has attracted much attention in recent years. Multiple studies have proven the effectiveness of voice therapy with telepractice. However, voice evaluations are still mostly conducted in person due to the lack of sensitive acoustic analysis methods. METHODS: This study examined various acoustic analysis methods for voice evaluation in telepractice. Eighteen female elementary school teachers with self-reported voice disorders volunteered to participate in the study. Speech samples were collected before and after the interventions using two voice sampling methods concurrently. One set of data was collected using the traditional voice sample collection method by the therapist in person. The second set of data was collected on the same speech samples using the clients' own smartphones, and the collected voice samples were later sent to the researcher for further acoustic analysis. The voice type component (VTC) measurement represented the proportion of different VTCs in a voice by measuring the chaos and intrinsic dimension. RESULTS: Voice analyses were conducted on both sets of data, and the correlation between the two sampling procedures was analyzed. It appears that the VTC could be a more reliable method for producing acoustic analysis results with voice samples collected from smartphones compared to other objective voice assessment procedures. This reliability has been demonstrated via statistical analysis, including correlation coefficient, pairwise t test, d-prime, and area under the curve. The results of this study highlighted the VTC as an effective and accurate acoustic analysis method in tele-evaluation. CONCLUSIONS: This feasible voice sampling method, which utilizes participants' own smartphones, will reduce barriers to accessing limited voice specialists due to distance and will decrease the cost of care by minimizing expenses associated with travel and additional equipment for voice sampling. Ultimately, this approach will enhance the effectiveness of voice care delivered through telepractice to patients in remote and underserved areas.

Pre-clinical evaluation of APrevent® VOIS for unilateral vocal fold paralysis medialization.

Objective: To evaluate the concept and efficacy of an adjustable implant (Prototype SH30: porcine implant and APrevent® VOIS: human concept) for treatment of unilateral vocal fold paralysis (UVFP) via in vivo mini-pig studies, human computed tomographic (CT) and magnetic resonance (MR) image analysis, ex-vivo aerodynamic and acoustic analysis. Methods: Feasibility testing and prototype implantation were performed using in-vivo UVFP porcine model (n = 8), followed by a dimensional finding study using CT and MR scans of larynges (n = 75) for modification of the implant prototypes. Acoustic and aerodynamic measurements were recorded on excised canine (n = 7) larynges with simulated UVFP before and after medialization with VOIS-Implant. Results: The prototype showed in the in-vivo UVFP porcine model an improved glottic closure from grade 6 incomplete closure to complete closure (n = 5), to grade 2 incomplete closure (n = 2) and grade 3 incomplete closure (n = 1). On human CT/MR scans the identification of the correct size was successful in 97.3% using the thyroid cartilage alar "distance S" as the only parameter, which is an important step towards procedure standardization and implant design. Results were confirmed with implantation in human laryngeal cadavers (n = 44). Measurements of the acoustic and aerodynamic effects after implantation showed a significant decreased phonation threshold pressure (p = .0187), phonation threshold flow (p = .0001) and phonation threshold power (p = .0046) on excised canine larynges with simulated UVFP. Percent jitter and percent shimmer decreased (p = .2976; p = .1771) but not significant. Conclusions: Based on the preclinical results four sizes, differing in medial length, implant width and expansion direction of silicone cushions, seem to be enough to satisfy laryngeal size variations. This concept is significantly effective in medializing UVFP and improving the aerodynamic and acoustic qualities of phonation as reported in a preliminary clinical outcome study with long-term implantation. Level of Evidence: N/A.

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

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

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

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

Office-Based Photodynamic Therapy Using Locally Applied 5-aminolevulinic Acid and 635 nm Laser for Laryngeal Leukoplakia.

OBJECTIVE: Photodynamic therapy (PDT) is a minimally invasive method with strong tissue selectivity and nonthermal effects. We aim to investigate the efficacy of an in-office method utilizing PDT with local application of 5-aminolevulinic acid (ALA) and 635 nm diode laser for treating laryngeal leukoplakia. STUDY DESIGN: Retrospective cohort study. SETTING: Outpatient clinic-tertiary medical center. METHODS: This study reviewed 32 patients with laryngeal leukoplakia, including 11 recurrent cases after surgery. All the procedures were performed in an office setting under topical anesthesia. Fifteen percent ALA solution was locally applied to the lesion through a flexible laryngoscope. Light illumination was performed using a 635 nm diode laser through a 400 µm optic fiber. The power density was 165 mW/cm2 to reach 100 J/cm2 . Results of laryngostroboscopy and voice evaluation during follow-up were collected. RESULTS: The mean follow-up was 7.91 ± 4.83 (3-18) months. Thirty-nine procedures were performed, including 1 session for 27 patients, 2 sessions for 3 patients, and 3 sessions for 2 patients. The total response rate was 96.875% (31/32), including complete responses in 26 (81.25%) patients, partial responses in 5 patients (15.625%), and no response in 1 patient (3.125%). It appeared that PDT selectively eliminated the leukoplakia without affecting lamina propria and the surrounding normal mucosa remained unharmed. Scores of Voice Handicap Index-10, jitter, shimmer, and harmonic-to-noise ratio were significantly improved after PDT. CONCLUSION: Office-based PDT is an effective, repeatable, and practical method for treating laryngeal leukoplakia. Local application of ALA is sufficient to achieve photodynamic reactions. PDT could eliminate laryngeal leukoplakia selectively while protecting the normal laryngeal structure.

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

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

To Explore the Changes and Differences of Microstructure of Vocal Fold in Vocal Fold Paralysis and Cricoarytenoid Joint Dislocation by Diffusion Tensor Imaging.

OBJECTIVE: The diffusion characteristics of water molecules were measured in the vocal folds of canines exhibiting unilateral vocal fold paralysis and unilateral cricoarytenoid joint dislocation. These characteristics were used in conjunction with a histological examination of the microstructural changes of vocal fold muscle fibers to explore the feasibility of diffusion tensor imaging (DTI) in distinguishing unilateral vocal fold paralysis and unilateral cricoarytenoid joint dislocation as well as evaluating microstructural changes. METHODS: Ten beagles were randomly divided into three groups: four in the unilateral vocal fold paralysis group, four in the unilateral cricoarytenoid joint dislocation group, and two in the normal group. Unilateral recurrent laryngeal nerve resection was performed in the vocal fold paralysis group. Unilateral cricoarytenoid joint dislocation surgery was performed in the dislocation group. No intervention was performed in the normal group. Four months postintervention, the larynges were excised and put into a magnetic resonance imaging (MRI) system (9.4T BioSpec MRI, Bruker, German) for scanning, followed by an analysis of diffusion parameters among the different groups for statistical significance. After MRI scanning, the vocal folds were cut into sections, stained with hematoxylin and eosin, and scanned digitally. The mean cross-sectional area of muscle fibers, and the mean diameter of muscle fibers in the vocal folds were calculated by target detection and extraction technology. Mean values of each measurement were used to compare the differences among the three groups. Pearson correlation analysis was performed on the DTI parameters and the results from histological section extraction. RESULTS: The paralysis group had significantly higher Fractional Anisotropy (FA) compared to the dislocation group and normal group (P = 0.004). The paralysis group also had a significantly lower Tensor Trace value compared to the dislocation group and normal group (P = 0.000). The average cross-sectional area of vocal fold muscle fibers in the paralysis group was significantly smaller than the dislocation group and normal group (P = 0.000). Pearson correlation analysis yielded values of, r = -0.785, P = 0.01 between the average cross-sectional area of vocal muscle fibers and FA, and values of r = 0.881, P = 0.00 between Tensor Trace and the average cross-sectional area of vocal muscle. CONCLUSION: FA and Tensor Trace can be used as effective parameters to reflect the changes of microstructure in vocal fold paralysis and cricoarytenoid joint dislocation. DTI is an objective and quantitative method to effectively evaluate unilateral vocal fold paralysis and unilateral cricoarytenoid joint dislocation, also capable of noninvasively evaluating vocal fold muscle fiber microstructure.

The Influence of Voice Training on Vocal Learner's Objective Acoustic Voice Components.

OBJECTIVE: Acoustic parameters of voice were studied in music majors throughout 18 months of training to understand the influence of voice training on voice. METHODS: Twenty-three students from Xiamen Music School between 12 and 15 years old were enrolled. Acoustic examination was performed three times- every 6 months for 18 months. Various traditional acoustic parameters were measured, including dysphonia severity index (DSI), jitter, and D-value of vocal range. Nonlinear dynamic measures were also measured, including diffusive chaos to construct voice type component profiles (VTCPs), spectrum convergence ratio, and nonlinear energy difference ratio. The results were analyzed by multivariate analysis of variance. RESULTS: Over the study duration, there was an improvement of DSI (P = 0.002), and D-value of vocal range (P = 0.000). Among nonlinear parameters, only voice type component data demonstrated significant changes during the study duration. Both Voice Type Component 1(VTC1) and VTC3 values differed from Time 1 to Time 2 as well as from Time 1 to Time 3. The proportion of VTC1 in samples generally decreased, while VTC3, representative of aperiodicity, increased. Both nonlinear energy difference ratio and spectrum convergence ratio exhibited no significant changes throughout the study. CONCLUSION: Professional voice training can improve DSI and D-value of vocal range in singers' voices. These parameters have potential to be used for voice training evaluation and screening. Many nonlinear parameters did not detect differences in the healthy voices studied, but VTCPs created using intrinsic dimension present a valuable new method, visualizing increases in aperiodicity of the speaking voices after professional voice training.

5-Aminolevulinic Acid-Mediated Photodynamic Therapy Improves Vocal Fold Wound Healing in Rats.

OBJECTIVE: Studies showed that photodynamic therapy (PDT) might be able to prevent vocal fold scar formation when treating laryngeal lesions. We aim to investigate if PDT improves vocal wound healing and reduces scar formation in both prophylactic and remodeling procedures performed in vivo. STUDY DESIGN: In vivo. METHODS: Vocal fold stripping was performed in Sprague-Dawley rats. PDT was performed with intraperitoneal injection of 100 mg/kg 5-Aminolevulinic Acid (5-ALA) and 635 nm laser irradiation of 20, 40, and 60 J/cm2 . PDT was performed immediately after surgery to study the prophylactic effect and 4 weeks after surgery to study the remodeling effect. Gene expression was evaluated with real-time PCR at 1 week after PDT. Histologic evaluations were performed 12 weeks after PDT, including hematoxylin-eosin, Masson, Alcian blue staining, and immunohistochemical staining of collagen I and III. RESULTS: PDT induced similar effects on the vocal fold wound healing outcomes in both prophylactic and remodeling procedures. Expression of MMP8, MMP13, HAS2, and TGFß1 was significantly elevated. Histologic evaluation revealed significantly increased thickness, decreased density of collagen, and increased deposition of hyaluronic acid in the lamina propria. Immunohistochemistry also revealed better distribution and reduced density of collagen I and III. The most obvious changes were seen in the 60 J/cm2 PDT group. CONCLUSION: PDT could significantly improve vocal wound healing by providing both prophylactic effects and remodeling effects. It may be a minimally invasive treatment for vocal fold lesions with slight vocal scarring, and may be used to treat acute or chronic vocal injury to reduce vocal scarring. LEVEL OF EVIDENCE: N/A Laryngoscope, 133:1943-1951, 2023.

Field-tuned ferroquadrupolar quantum phase transition in the insulator TmVO4.

We report results of low-temperature heat-capacity, magnetocaloric-effect, and neutron-diffraction measurements of TmVO4, an insulator that undergoes a continuous ferroquadrupolar phase transition associated with local partially filled 4f orbitals of the thulium (Tm[Formula: see text]) ions. The ferroquadrupolar transition, a realization of Ising nematicity, can be tuned to a quantum critical point by using a magnetic field oriented along the c axis of the tetragonal crystal lattice, which acts as an effective transverse field for the Ising-nematic order. In small magnetic fields, the thermal phase transition can be well described by using a semiclassical mean-field treatment of the transverse-field Ising model. However, in higher magnetic fields, closer to the field-tuned quantum phase transition, subtle deviations from this semiclassical behavior are observed, which are consistent with expectations of quantum fluctuations. Although the phase transition is driven by the local 4f degrees of freedom, the crystal lattice still plays a crucial role, both in terms of mediating the interactions between the local quadrupoles and in determining the critical scaling exponents, even though the phase transition itself can be described via mean field. In particular, bilinear coupling of the nematic order parameter to acoustic phonons changes the spatial and temporal fluctuations of the former in a fundamental way, resulting in different critical behavior of the nematic transverse-field Ising model, as compared to the usual case of the magnetic transverse-field Ising model. Our results establish TmVO4 as a model material and electronic nematicity as a paradigmatic example for quantum criticality in insulators.

Do the Nonlinear Dynamic Acoustic Measurements, Nonlinear Energy Difference Ratio and Spectrum Convergence Ratio, Correlate with Perceptual Evaluation of Esophageal Voice Speakers?

BACKGROUND: The acoustic assessment of phonation after total laryngectomy is challenged by signal aperiodicity which makes frequency-based acoustic measures less reliable. This is important for patients who use esophageal voice since voice samples mostly include type III (highly aperiodic) and 4 (chaotic) signals. As such, using non-linear measures, which are better suited for aperiodic phonation, may be useful to investigate the relationship between acoustic signal characteristics and perception of esophageal voice quality. OBJECTIVES: This study aimed to investigate whether nonlinear dynamic acoustic methods, nonlinear energy difference Ratio (NEDR) and spectrum convergence ratio (SCR), were correlated with perceptual measures in subjects who used esophageal phonation. METHODS: Thirty-one subjects who had undergone total laryngectomy and use esophageal voice as a rehabilitation method were included in this study. Expert and non-expert raters listened to the esophageal voice samples from the subjects and rated vowels and connected speech samples on a scale from 1 to 7 on dysphonia severity and intelligibility. In addition, non-linear acoustic analysis was performed to calculate NEDR and SCR. Analysis from the raters was compared to the non-linear acoustic analysis to find the correlation between the variables. RESULTS: There were no significant correlations between any of the non-linear acoustic measures NEDR and SCR and the perceptual ratings at the significance level of 0.05. Correlations were calculated for each acoustic measure among the expert raters and among the non-expert raters in both connected speech samples and sustained vowel fragments. CONCLUSIONS: In conclusion, the nonlinear dynamic acoustic analyses of spectrum convergence ratio and nonlinear energy difference ratio do not have a significant correlation with perceptual measures of esophageal voice.

The Effect of Mandarin Vowels on Acoustic Analysis: A Prospective Observational Study.

OBJECTIVES: Although vowels are of interest for acoustic analysis in clinics, there is no consensus regarding the effect of vowel selection on acoustic perturbation parameters. This study aimed to reveal the effects of Mandarin vowels on acoustic measurements. STUDY DESIGN: A prospective observational study. METHODS: This prospective observational study enrolled normal phonation Mandarin speakers at the Otolaryngology Department of the Eye & ENT Hospital affiliated with Fudan University from December 2020 to August 2021. This study recruited 107 normal-voiced Mandarin speakers (59 women and 49 men) with a median age of 26 (22, 33) years old. The objective measures included traditional acoustic parameters (fundamental frequency, harmonic-to-noise ratio, percent jitter, and percent shimmer) and cepstral analysis (smoothed cepstral peak prominence) of six Mandarin vowels (ɑ /a/, o /o/, e /ɤ/, i /i/, u /u/, ü /y/). RESULTS: The acoustic analysis revealed no significant differences in the fundamental frequency among vowels. The low vowel /a/ had the highest values for percent jitter and percent shimmer and the lowest harmonic-to-noise ratio value. The back vowel /u/ had the lowest cepstral measures (P < 0.05). CONCLUSIONS: The acoustic analysis significantly varied across the different Mandarin vowels, and these differences must be considered for the effective clinical application of objective evaluations.

Glottic Insufficiency in the Vertical Plane in Patients With Unknown-Source Unilateral Vocal Fold Hypomobility.

OBJECTIVE: To observe the laryngeal CT and strobe laryngoscopy signs of unilateral vocal fold hypomobility (UVFHM) in patients with well-closed glottises in the horizontal plane. METHODS: A retrospective analysis was performed on 18 subjects with well-closed glottises in the horizontal plane using strobe laryngoscopy, 9 patients diagnosed with unilateral vocal fold hypomobility with an unknown etiology were enrolled in the UVFHM group, and 9 healthy matched subjects with symmetrical bilateral vocal fold movement were enrolled in the control group. Vertical plane distances of bilateral vocal folds and three-dimensional structural parameters of vocal folds were measured through laryngeal CT. Glottic insufficiency in the vertical plane and reflux findings scores (RFS) were assessed under laryngeal CT and strobe laryngoscopy. Reflux symptom index (RSI) were collected. SPSS25.0 software was used for statistical analysis. RESULTS: The height differences in vertical plane and thicknesses of bilateral vocal folds in the UVFHM group were larger than those in the control (P < 0.05), while the length, width and subglottic convergence angle of the vocal folds were not statistically significant between the two groups (P > 0.05). In the UVFHM group, laryngeal CT showed that 77.78% of patients (7/9) had glottic insufficiency in the vertical plane, with height differences ranging from 0.3 to 1.9 mm and a mean of 0.76mm. However, strobe laryngoscopy showed that 33.33% (3/9) had glottic insufficiency in the vertical plane. The proportion of patients with glottic insufficiency in vertical plane in the UVFHM group was significantly higher than that in the control group (P < 0.05). RSI and RFS scores of the UVFHM group were higher than those of the control group (P < 0.05). CONCLUSION: Glottic insufficiency in the vertical plane often occurred in patients with UVFHM with an unknown cause of hoarseness, so the presence of glottic insufficiency in the vertical plane should be considered when hoarseness is detected by clinicians. Laryngeal dynamic CT can enhance the diagnostic rate compared to strobe laryngoscopy. Unexplained UVFHM patients have higher RSI and RFS compared to control subjects, warranting further research about the relationship between UVFHM and laryngopharyngeal reflux.