Efficacy of Videostroboscopy and High-Speed Videoendoscopy to Obtain Functional Outcomes From Perioperative Ratings in Patients With Vocal Fold Mass Lesions

Effect of Nebulization on Laryngeal Parameters: Analysis Using High-Speed Digital Videolaryngoscopy

INTRODUCTION

Superficial laryngeal hydration, obtained through nebulization, is related to the moisture level on the epithelial surfaces of the vocal folds, modifying their biomechanical and aerodynamic properties. Through high-speed videolaryngoscopy it is possible to obtain objective data for laryngeal analysis after nebulization and a better understanding of this phenomenon OBJECTIVE: To verify the effects of nebulization with saline solution on laryngeal parameters of digital videokymography obtained by high-speed videolaryngoscopy examination in women and men with and without laryngeal alterations METHOD: This is a clinical, comparative intra-subject study. Fifty-nine adults were selected, with and without laryngeal alterations, 30 females and 29 males. Digital videokymographs in the anterior, middle and posterior thirds of the vocal folds of the participants were analyzed before and after nebulization with 0.9% saline solution.

RESULTS

Women without laryngeal alterations showed more parameters changes after nebulization, in which there was a decrease in maximum and medium opening, amplitude of opening of the left and right vocal fold in the anterior glottal third, and an increase of the percentage of closure of the vocal folds. These results indicate a minor extent of lateral excursion of the vocal folds during phonation. In women with laryngeal alterations, the parameters that changed after nebulization were the increased frequency of opening of the left and right vocal folds in the topography of the posterior third. In men, nebulization did not change the variables studied, except for the amplitude of the right vocal fold in men with laryngeal alterations, in the analysis of the posterior glottic third.

CONCLUSION

The results suggest that surface hydration modifies laryngeal dynamics differently between genders. After nebulization with saline solution, women without laryngeal alterations showed a decrease in the lateralization of the vocal folds during phonation, suggesting a better phonatory efficiency.

Hemorrhagic Pseudocyst (Polyst) and True Hemorrhagic Cyst of the Vocal Fold

OBJECTIVES

Though hemorrhagic vocal fold polyps are a common entity, hemorrhagic vocal fold cysts have not been previously described. In our study, we have evaluated patients who were diagnosed on stroboscopy with "hemorrhagic" cysts.

METHODS

This 18-month retrospective study has received institutional ethics clearance. Using the database of our voice clinic, 14 patients diagnosed with hemorrhagic cysts by stroboscopy were reviewed. Age, sex, chief complaints, symptom duration, videostroboscopy findings, surgical details, and histopathology were noted.

RESULTS

Out of a total 14 patients, 12 were males with a mean age of presentation of 41 years. The duration of hoarseness ranged from 2-24 months. Videostroboscopy revealed a markedly decreased amplitude of the mucosal waves over a well-delineated ovoid or spheroid hemorrhagic lesion, which seemed tethered down by overlying vocal fold epithelium. All patients had operative findings of a well-encapsulated hemorrhagic lesion in the superficial lamina propria with anterior and posterior fibrotic bands. Histopathology of 13 patients was similar and revealed a hemorrhagic polypoidal lesion. A pseudo-capsule could be identified occasionally. These lesions seemed to be hemorrhagic pseudocysts, named "polyst" by us. In one male patient, the histopathology revealed a true vocal fold cyst (type C Koren) with hemorrhage.

CONCLUSIONS

A hemorrhagic pseudocyst (polyst) of the vocal fold has stroboscopic and surgical findings resembling a true vocal fold cyst with hemorrhage; however, histologically it resembles a hemorrhagic polyp. A true hemorrhagic cyst however is typically a type C Koren cyst with hemorrhage. Both these entities have not been previously described.

Framework for Indirect Spatial Calibration of the Horizontal Plane of Endoscopic Laryngeal Images

OBJECTIVE

Calibrated horizontal-plane measurements from laryngeal images could contribute significantly to refining evidence-based practice and developing patient-specific models and precision-medicine approaches. Laser-projection endoscopes can address the need for direct calibrated measures; however, these systems are not widely available. This study presents the framework for an alternative indirect horizontal-plane calibration approach.

METHOD

A spatial attribute of a common object, a distinct characteristic that is maintained across images, may be used as a scale for the normalization of other spatial measurements. The outcome of this indirect approach could be used for absolute measurements (eg, in units of mm) or relative measurements (eg, percent change), depending on the information that is available from the common attribute. The required conditions of a common attribute for achieving a valid calibration outcome were studied. Three conditions were derived: registration accuracy of the common attribute, size consistency of the common attribute, and similarity in the vertical distance between the region of interest (ROI) (eg, vocal fold) and the common attribute. Any common attribute satisfying these three conditions was called proper and would result in a valid indirect calibration outcome. Three tests were presented for evaluating the properness of a common attribute. A data-driven statistical method was presented that can evaluate the registration accuracy of a common attribute. The second test used variation in calibrated lengths of a common attribute under different phonatory configurations for evaluating the size consistency condition. Finally, the effect of differences between vertical distances of the ROI and the common attribute was mathematically tested and quantified. The application of the proposed framework for indirect calibration was demonstrated using a pre existing dataset with a vocal fold as the ROI and four different common attributes (vocal fold length, vocal fold width, blood vessel on the vocal fold, and blood vessel on nearby tissue).

RESULTS

The proposed registration-accuracy test was able to detect and eliminate instances of common attributes with low accuracies. The analysis suggested that among the studied four common attributes, the vocal fold length had the highest (ie, best) registration accuracy; however, the vocal fold length exhibited the lowest (ie, worst) size consistency. The analysis also suggested that, among the studied attributes, the vocal fold width offered the best trade-off among the three conditions and, hence, was a proper common attribute for calibrating spatial aspects of the vocal folds (length, displacement of edges, velocity, etc).

CONCLUSION

Indirect calibration is a feasible alternative for calibration of laryngeal endoscopic images, given a proper common attribute is selected. Future work is needed to systematically evaluate the effects of various phonatory conditions on the characteristics of common attributes.

Reconstruction of Vocal Fold Medial Surface 3D Trajectories: Effects of Neuromuscular Stimulation and Airflow

INTRODUCTION

Analysis of medial surface dynamics of the vocal folds (VF) is critical to understanding voice production and treatment of voice disorders. We analyzed VF medial surface vibratory dynamics, evaluating the effects of airflow and nerve stimulation using 3D reconstruction and empirical eigenfunctions (EEF).

STUDY DESIGN

In vivo canine hemilarynx phonation.

METHODS

An in vivo canine hemilarynx was phonated while graded stimulation of the recurrent and superior laryngeal nerves (RLN and SLN) was performed. For each phonatory condition, vibratory cycles were 3D reconstructed from tattooed landmarks on the VF medial surface at low, medium, and high airflows. Parameters describing medial surface trajectory shape were calculated, and underlying patterns were emphasized using EEFs. Fundamental frequency and smoothed cepstral peak prominence (CPPS) were calculated from acoustic data.

RESULTS

Convex-hull area of landmark trajectories increased with increasing flow and decreasing nerve activation level. Trajectory shapes observed included circular, ellipsoid, bent, and figure-eight. They were more circular on the superior and anterior VF, and more elliptical and line-like on the inferior and posterior VF. The EEFs capturing synchronal opening and closing (EEF1) and alternating convergent/divergent (EEF2) glottis shapes were mostly unaffected by flow and nerve stimulation levels. CPPS increased with higher airflow except for low RLN activation and very dominant SLN stimulation.

CONCLUSION

We analyzed VF vibration as a function of neuromuscular stimulation and airflow levels. Oscillation patterns such as figure-eight and bent trajectories were linked to high nerve activation and flow. Further studies investigating longer sections of 3D reconstructed oscillations are needed.

LEVEL OF EVIDENCE

N/A, Basic Science Laryngoscope, 134:1249-1257, 2024.

Value of high-speed videoendoscopy as an auxiliary tool in differentiation of benign and malignant unilateral vocal lesions

PURPOSE

The study aimed to assess the relevance of objective vibratory parameters derived from high-speed videolaryngoscopy (HSV) as a supporting tool, to assist clinicians in establishing the initial diagnosis of benign and malignant glottal organic lesions.

METHODS

The HSV examinations were conducted in 175 subjects: 50 normophonic, 85 subjects with benign vocal fold lesions, and 40 with early glottic cancer; organic lesions were confirmed by histopathologic examination. The parameters, derived from HSV kymography: amplitude, symmetry, and glottal dynamic characteristics, were compared statistically between the groups with the following ROC analysis.

RESULTS

Among 14 calculated parameters, 10 differed significantly between the groups. Four of them, the average resultant amplitude of the involved vocal fold (AmpInvolvedAvg), average amplitude asymmetry for the whole glottis and its middle third part (AmplAsymAvg; AmplAsymAvg_2/3), and absolute average phase difference (AbsPhaseDiffAvg), showed significant differences between benign and malignant lesions. Amplitude values were decreasing, while asymmetry and phase difference values were increasing with the risk of malignancy. In ROC analysis, the highest AUC was observed for AmpAsymAvg (0.719; p < 0.0001), and next in order was AmpInvolvedAvg (0.70; p = 0.0002).

CONCLUSION

The golden standard in the diagnosis of organic lesions of glottis remains clinical examination with videolaryngoscopy, confirmed by histopathological examination. Our results showed that measurements of amplitude, asymmetry, and phase of vibrations in malignant vocal fold masses deteriorate significantly in comparison to benign vocal lesions. High-speed videolaryngoscopy could aid their preliminary differentiation noninvasively before histopathological examination; however, further research on larger groups is needed.

Unraveling the complexities of pathological voice through saliency analysis

The human voice is an essential communication tool, but various disorders and habits can disrupt it. Diagnosis of pathological and abnormal voices is very important. Conventional diagnosis of these voice pathologies can be invasive and costly. Voice pathology disorders can be effectively detected using Artificial Intelligence and computer-aided voice pathology classification tools. Previous studies focused primarily on binary classification, leaving limited attention to multi-class classification. This study proposes three different neural network architectures to investigate the feature characteristics of three voice pathologies-Hyperkinetic Dysphonia, Hypokinetic Dysphonia, Reflux Laryngitis, and healthy voices using multi-class classification and the Voice ICar fEDerico II (VOICED) dataset. The study proposes UNet++ autoencoder-based denoiser techniques for accurate feature extraction to overcome noisy data. The architectures include a Multi-Layer Perceptron (MLP) trained on structured feature sets, a Short-Time Fourier Transform (STFT) model, and a Mel-Frequency Cepstral Coefficients (MFCC) model. The MLP model on 143 features achieved 97.1% accuracy, while the STFT model showed similar performance with increased sensitivity of 99.8%. The MFCC model maintained 97.1% accuracy but with a smaller model size and improved accuracy on the Reflux Laryngitis class. The study identifies crucial features through saliency analysis and reveals that detecting voice abnormalities requires the identification of regions of inaudible high-pitch sounds. Additionally, the study highlights the challenges posed by limited and disjointed pathological voice databases and proposes solutions for enhancing the performance of voice abnormality classification. Overall, the study's findings have potential applications in clinical applications and specialized audio-capturing tools.

High-Speed Videoendoscopy Enhances the Objective Assessment of Glottic Organic Lesions: A Case-Control Study with Multivariable Data-Mining Model Development

The aim of the study was to utilize a quantitative assessment of the vibratory characteristics of vocal folds in diagnosing benign and malignant lesions of the glottis using high-speed videolaryngoscopy (HSV).

METHODS

Case-control study including 100 patients with unilateral vocal fold lesions in comparison to 38 normophonic subjects. Quantitative assessment with the determination of vocal fold oscillation parameters was performed based on HSV kymography. Machine-learning predictive models were developed and validated.

RESULTS

All calculated parameters differed significantly between healthy subjects and patients with organic lesions. The first predictive model distinguishing any organic lesion patients from healthy subjects reached an area under the curve (AUC) equal to 0.983 and presented with 89.3% accuracy, 97.0% sensitivity, and 71.4% specificity on the testing set. The second model identifying malignancy among organic lesions reached an AUC equal to 0.85 and presented with 80.6% accuracy, 100% sensitivity, and 71.1% specificity on the training set. Important predictive factors for the models were frequency perturbation measures.

CONCLUSIONS

The standard protocol for distinguishing between benign and malignant lesions continues to be clinical evaluation by an experienced ENT specialist and confirmed by histopathological examination. Our findings did suggest that advanced machine learning models, which consider the complex interactions present in HSV data, could potentially indicate a heightened risk of malignancy. Therefore, this technology could prove pivotal in aiding in early cancer detection, thereby emphasizing the need for further investigation and validation.

Visual-perceptive assessment of glottic characteristics of vocal nodules by means of high-speed videoendoscopy

OBJECTIVE

Visual-perceptive assessment of glottic characteristics of vocal nodules by means of high-speed videoendoscopy.

METHODS

Descriptive observational research with convenience sampling of five laryngeal videos of women with an average age of 25 years. The diagnosis of vocal nodules was defined by two otolaryngologists, with 100% intra-rater agreement and 53.40% inter-rater agreement and five otolaryngologists as judge assessed the laryngeal videos based on an adapted protocol. The statistical analysis calculated measures of central tendency and dispersion, as well as percentage. The AC1 coefficient was used for agreement analysis.

RESULTS

In high-speed videoendoscopy imaging, vocal nodules are characterized by amplitude of the mucosal wave and muco-undulatory movement with magnitude between 50% and 60%. Non-vibrating segments of vocal folds are scarce, and the glottal cycle does not show a predominant phase, it is symmetric and periodic. Glottal closure is characterized by the presence of a mid-posterior triangular chink (double chink or isolated mid-posterior triangular chink), without movement of supraglottic laryngeal structures, with irregular contour of the free edge of vocal folds, which are vertically on-plane.

CONCLUSION

Vocal nodules present mid-posterior triangular chink and irregular free edge contour. Amplitude and mucosal wave were partially reduced.

LEVEL OF EVIDENCE

Level 4 (Case-series).

Videostroboscopy Versus High-Speed Videoendoscopy: Factors Influencing Ratings of Laryngeal Oscillation

PURPOSE

The purpose of this study was to determine whether patient voice-related diagnosis, severity of dysphonia, and rater's experience influence the relationship between laryngeal oscillation ratings made from videostroboscopic and high-speed videoendoscopic (HSV) exams.

METHOD

Stroboscopy and HSV exams from 15 patients with adductor spasmodic dysphonia (ADSD) and 15 with benign vocal fold lesions were rated for laryngeal oscillation and closure by 10 licensed speech-language pathologists (SLPs). Raters were divided into low- (< 5 years) and high-experience (> 5 years) groups. Ratings of vocal fold amplitude, mucosal wave, periodicity, phase symmetry, nonvibrating portion of the vocal fold, and glottal closure were examined using an online form adapted from the Voice Vibratory Assessment of Laryngeal Imaging (VALI).

RESULTS

Stroboscopy and HSV ratings were more strongly positively correlated for patients with benign vocal fold lesions (r between .43 and .75) than for those with ADSD (r between .40 and .68). Differences between stroboscopy and HSV exams were significantly greater for ratings of amplitude, mucosal wave, and periodicity in patients with ADSD than for patients with benign vocal fold lesions. Raters with < 5 years of experience showed significantly greater differences between stroboscopy and HSV ratings of amplitude and nonvibrating portion of the vocal fold for patients with ADSD only. Significantly greater differences between ratings of periodicity and phase symmetry were observed in patients with more severe dysphonia.

CONCLUSIONS

Differences in laryngeal ratings made between HSV and stroboscopy exams may be influenced by patient diagnosis, severity of dysphonia, and rater experience. Future study is warranted to determine how the differences observed influence clinical diagnosis and outcomes.

Non-Linear Image Distortions in Flexible Fiberoptic Endoscopes and their Effects on Calibrated Horizontal Measurements Using High-Speed Videoendoscopy

Laryngeal images obtained via high-speed videoendoscopy are an invaluable source of information for the advancement of voice science because they can capture the true cycle-to-cycle vibratory characteristics of the vocal folds in addition to the transient behaviors of the phonatory mechanism, such as onset, offset, and breaks. This information is obtained through relating the spatial and temporal features from acquired images using objective measurements or subjective assessments. While these images are calibrated temporally, a great challenge is the lack of spatial calibration. Recently, a laser-projection system allowing for spatial calibration was developed. However, various sources of optical distortions deviate the images from reflecting the reality. The main purpose of this study was to evaluate the effect of the fiberoptic flexible endoscope distortions on the calibration of images acquired by the laser-projection system. Specifically, it is shown that two sources of nonlinear distortions could deviate captured images from reality. The first distortion stems from the wide-angle lens used in flexible endoscopes. It is shown that endoscopic images have a significantly higher spatial resolution in the center of the field of view than in its periphery. The difference between the two could lead to as high as 26.4% error in calibrated horizontal measurements. The second distortion stems from variation in the imaging angle. It is shown that the disparity between spatial resolution in the center and periphery of endoscopic images increases as the imaging angle deviates from the perpendicular position. Furthermore, it is shown that when the imaging angle varies, the symmetry of the distortion is also affected significantly. The combined distortions could lead to calibrated horizontal measurement errors as high as 65.7%. The implications of the findings on objective measurements and subjective visual assessments are discussed. These findings can contribute to the refinement of the methods for clinical assessment of voice disorders. Considering that the studied phenomena are due to optical principles, the findings of this study, especially those related to the effects of the imaging angle, can provide further insights regarding other endoscopic instruments (eg, distal-chip and rigid endoscopes) and procedures (eg, gastroendoscopy and colonoscopy).

Assessment of Vocal Fold Stiffness by Means of High-Speed Videolaryngoscopy with Laryngotopography in Prediction of Early Glottic Malignancy: Preliminary Report

One of the most important challenges in laryngological practice is the early diagnosis of laryngeal cancer. Detection of non-vibrating areas affected by neoplastic lesions of the vocal folds can be crucial in the recognition of early cancerogenous infiltration. Glottal pathologies associated with abnormal vibration patterns of the vocal folds can be detected and quantified using High-speed Videolaryngoscopy (HSV), also in subjects with severe voice disorders, and analyzed with the aid of computer image processing procedures. We present a method that enables the assessment of vocal fold pathologies with the use of HSV. The calculated laryngotopographic (LTG) maps of the vocal folds based on HSV allowed for a detailed characterization of vibration patterns and abnormalities in different regions of the vocal folds. We verified our methods with HSV recordings from 31 subjects with a normophonic voice and benign and malignant vocal fold lesions. We proposed the novel Stiffness Asymmetry Index (SAI) to differentiate between early glottis cancer (SAI = 0.65 ± 0.18) and benign vocal fold masses (SAI = 0.16 ± 0.13). Our results showed that these glottal pathologies might be noninvasively distinguished prior to histopathological examination. However, this needs to be confirmed by further research on larger groups of benign and malignant laryngeal lesions.

Voice Handicap Index Changes After Microflap Surgery for Benign Vocal Fold Lesions Are Not Associated With Recommended Absolute Voice Rest Duration

PURPOSE

Voice rest is frequently prescribed after phonosurgery, but optimal type and duration for voice outcomes have not been demonstrated. Studies to date have been characterized by heterogeneity in surgical procedures and laryngeal diagnoses. We sought to analyze the effect of recommended absolute voice rest duration on outcomes of microflap surgery for benign vocal fold lesions. A secondary purpose was to identify patient factors associated with postoperative voice outcomes.

METHOD

Forty-three patients were included in this retrospective review of patients aged 18 years and above who underwent direct microlaryngoscopy with microflap for vocal fold polyp or cyst over a 5-year period at a multidisciplinary voice center. Duration of recommended postoperative absolute voice rest was classified as less than 7 days, 7 days, and more than 7 days. Demographic and vocal hygiene data and voice treatment history were collected. Outcome measures consisted of one pre- and two postoperative Voice Handicap Index (VHI) scores. Effects of recommended voice rest on outcomes were analyzed using mixed models for repeated measures. Effects of patient factors on outcomes were analyzed as exploratory measures. Stroboscopy ratings were analyzed descriptively.

RESULTS

Thirteen patients were recommended 7 days of absolute voice rest, 15 were recommended less than 7 days, and 15 were recommended more than 7 days. Postoperatively, VHI scores significantly improved for all patients. Voice rest as a continuous variable was associated with the Functional subscale score in the short term, but there was no effect on VHI total score and no longer term effect of voice rest on any outcome. Age, sex, and preoperative voice therapy were associated with at least one VHI subscale score on at least one time point.

CONCLUSION

VHI outcomes of microflap surgery for polyps and cysts do not differ by duration of recommended absolute postoperative voice rest.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19178459.

Comparative analysis of high-speed videolaryngoscopy images and sound data simultaneously acquired from rigid and flexible laryngoscope: a pilot study

High-Speed Videoendoscopy (HSV) is becoming a robust tool for the assessment of vocal fold vibration in laboratory investigation and clinical practice. We describe the first successful application of flexible High Speed Videoendoscopy with innovative laser light source conducted in clinical settings. The acquired image and simultaneously recorded audio data are compared to the results obtained by means of a rigid endoscope. We demonstrated that the HSV recordings with fiber-optic laryngoscope have enabled obtaining consistently bright, color images suitable for parametrization of vocal fold oscillation similarly as in the case of the HSV data obtained from a rigid laryngoscope. The comparison of period and amplitude perturbation parameters calculated on the basis of image and audio data acquired from flexible and rigid HSV recording objectively confirm that flexible High-Speed Videoendoscopy is a more suitable method for examination of natural phonation. The HSV-based measures generated from this kymographic analysis are arguably a superior representation of the vocal fold vibrations than the acoustic analysis because their quantification is independent of the vocal tract influences. This experimental study has several implications for further research in the field of HSV application in clinical assessment of glottal pathologies nature and its effect on vocal folds vibrations.

Laryngeal High-Speed Videoendoscopy with Laser Illumination: A Preliminary Report

&lt;br&gt;&lt;b&gt;Introduction:&lt;/b&gt; Advances in computer image analysis have enabled the use of new functional imaging methods in the diagnosis of laryngeal diseases. Particularly interesting techniques of dynamic laryngeal imaging involve High Speed Videoendoscopy (HSV). This still-developed technique allows to overcome the limitations of laryngovideostroboscopy (LVS) and a more detailed analysis of the glottal function based on the image of the actual vibrations of the vocal folds. It also enables the determination of objective coefficients parameterizing phonatory vibrations of the vocal folds.&lt;/br&gt; &lt;br&gt;&lt;b&gt;Aim:&lt;/b&gt; The aim of this pilot study was to evaluate the use of a high-speed videoendoscopy set with laser illumination for the diagnosis of glottic pathology in ENT practice.&lt;/br&gt; &lt;br&gt;&lt;b&gt;Material and methods:&lt;/b&gt; The study included 40 patients who underwent LVS followed by HSV. The modern HSV examination kit - Advanced Larynx Imager System (ALIS), used for the first time in a clinical setting in Poland, is characterized by significantly improved, compared to the previously used high-speed cameras, operational parameters - a light head, the possibility of continuous lighting operation without excessive heating of the head tip, registration of the image in full color scale. Thanks to such modernization, the safety and course of the examination do not differ from laryngoscopy conducted with commonly used recorders. The device owes some of these improvements to a laser illuminator which was used for the first time as the main light source in a high-speed camera. In the study, two cases were selected to present the results of HSV and the analysis of the generated kymograms - a woman with no glottic pathology and a man with a polyp of the right vocal fold. In the first case, the HSV examination compared with the LVS revealed a discrete glottis functional disorder in the form of a tendency to hyperphonation. The patient with an organic lesion had a clearly visible irregularity of vocal fold vibrations, which also allowed to trace mucosal wave disturbances related to its reflection from the pathological structure of the glottis and the formation of a return wave, both on the fold affected by the lesion and, to a lesser extent, contralaterally. The glottic dysfunctions observed in the studied patients were confirmed in the generated kymograms and the graphs of the glottal width waveform (GWW), as well as in the parameters calculated on their basis, assessing the frequency and amplitude of phonatory vibrations.&lt;/br&gt; &lt;br&gt;&lt;b&gt;Conclusions:&lt;/b&gt; The use of high-speed videoendoscopy allows for a much more accurate assessment of the phonatory function of the glottis than in laryngovideostroboscopy. The presented HSV system allows for obtaining high quality kinematic images of the larynx, color fidelity, and contrast. The use of this technology in laryngological practice enables precise structural and functional assessment of the glottis and detection of discrete phonation disorders that elude the techniques used so far.&lt;/br&gt.

Vocal fold oscillation pattern changes related to loudness in patients with vocal fold mass lesions

Introduction

Vocal fold mass lesions can affect vocal fold oscillation patterns and therefore voice production. It has been previously observed that perturbation values from audio signals were lower with increased loudness. However, how much the oscillation patterns change with gradual alteration of loudness is not yet fully understood.

Material and methods

Eight patients with vocal fold mass lesions were asked to perform a glide from minimum to maximum loudness on the vowel /i/, ƒ_o of 125 Hz for male or 250 Hz for female voices. During phonation the subjects were simultaneously recorded with transnasal high speed videoendoscopy (HSV, 20,000 fps), electroglottography (EGG), and an audio recording. Based on the HSV material the Glottal Area Waveform (GAW) was segmented and GAW parameters were computed.

Results

The greatest vocal fold irregularities were observed at different values between minimum and maximum sound pressure level. There was a relevant discrepancy between the HSV and EGG derived open quotients. Furthermore, the EGG derived sample entropy and GAW values also evidenced different behavior.

Conclusions

The amount of vocal fold irregularity changes with varying loudness. Therefore, any evaluation of the voice should be performed under different loudness conditions. The discrepancy between EGG and GAW values appears to be much stronger in patients with vocal fold mass lesions than those with normal physiological conditions.

Level of evidence

4.

Maximum and Minimum Phonatory Glottal Area before and after Treatment for Vocal Nodules

Background: Vocal fold nodules (VFNs) are a challenge for otolaryngologists. Glottal area (GA) waveform analysis is an examination method used for assessing vocal fold vibration and function. However, GA in patients with VFNs has rarely been studied. This study investigated the maximum and minimum GA in VFN patients using modern waveform analysis combining ImageJ software and videostroboscopy. Methods: This study enrolled 42 patients newly diagnosed with VFN, 15 of whom received voice therapy and 27 of whom underwent surgery. Acoustic parameters and maximum phonation time (MPT) were recorded, and patients completed the Chinese Voice Handicap Index-10 (VHI-C10) before and after treatment. After videostroboscopy examination, the maximum and minimum GAs were calculated using ImageJ software. The GAs of patients with VFNs before and after surgery or voice therapy were analyzed. Results: The MPTs of the patients before and after voice therapy or surgery did not change significantly. VHI-C10 scores decreased after voice therapy but the decrease was nonsignificant (14.0 ± 8.44 vs. 9.40 ± 10.24, p = 0.222); VHI-C10 scores were significantly decreased after surgery (22.53 ± 7.17 vs. 12.75 ± 9.84, p = 0.038). Voice therapy significantly increased the maximum GA (5.58 ± 2.41 vs. 8.65 ± 3.17, p = 0.012) and nonsignificantly decreased the minimum GA (0.60 ± 0.73 vs. 0.21 ± 0.46, p = 0.098). Surgery nonsignificantly increased the maximum GA (6.34 ± 3.82 vs. 8.73 ± 5.57, p = 0.118) and significantly decreased the minimum GA (0.30 ± 0.59 vs. 0.00 ± 0.00, p = 0.036). Conclusion: This study investigated the GA of patients with VFNs who received voice therapy or surgery. The findings indicated that voice therapy significantly increased maximum GA and surgery significantly decreased minimum GA. GA analysis could be applied to evaluate the efficacy of voice therapy, and it may help physicians to develop precise treatment for VFN patients (either by optimizing voice therapy or by performing surgery directly).

Laryngeal Image Processing of Vocal Folds Motion

This review provides a comprehensive compilation, from a digital image processing point of view of the most important techniques currently developed to characterize and quantify the vibration behaviour of the vocal folds, along with a detailed description of the laryngeal image modalities currently used in the clinic. The review presents an overview of the most significant glottal-gap segmentation and facilitative playbacks techniques used in the literature for the mentioned purpose, and shows the drawbacks and challenges that still remain unsolved to develop robust vocal folds vibration function analysis tools based on digital image processing.