Objective Measures of Laryngeal Imaging: What Have We Learned Since Dr. Paul Moore

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.

Deep Learning-Based Detection of Glottis Segmentation Failures

Medical image segmentation is crucial for clinical applications, but challenges persist due to noise and variability. In particular, accurate glottis segmentation from high-speed videos is vital for voice research and diagnostics. Manual searching for failed segmentations is labor-intensive, prompting interest in automated methods. This paper proposes the first deep learning approach for detecting faulty glottis segmentations. For this purpose, faulty segmentations are generated by applying both a poorly performing neural network and perturbation procedures to three public datasets. Heavy data augmentations are added to the input until the neural network's performance decreases to the desired mean intersection over union (IoU). Likewise, the perturbation procedure involves a series of image transformations to the original ground truth segmentations in a randomized manner. These data are then used to train a ResNet18 neural network with custom loss functions to predict the IoU scores of faulty segmentations. This value is then thresholded with a fixed IoU of 0.6 for classification, thereby achieving 88.27% classification accuracy with 91.54% specificity. Experimental results demonstrate the effectiveness of the presented approach. Contributions include: (i) a knowledge-driven perturbation procedure, (ii) a deep learning framework for scoring and detecting faulty glottis segmentations, and (iii) an evaluation of custom loss functions.

Drug delivery systems for wound healing treatment of upper airway injury

INTRODUCTION

Endotracheal intubation is a common procedure to maintain an open airway with risks for traumatic injury. Pathological changes resulting from intubation can cause upper airway complications, including vocal fold scarring, laryngotracheal stenosis, and granulomas and present with symptoms such as dysphonia, dysphagia, and dyspnea. Current intubation-related laryngotracheal injury treatment approaches lack standardized guidelines, relying on individual clinician experience, and surgical and medical interventions have limitations and carry risks.

AREAS COVERED

The clinical and preclinical therapeutics for wound healing in the upper airway are described. This review discusses the current developments on local drug delivery systems in the upper airway utilizing particle-based delivery systems, including nanoparticles and microparticles, and bulk-based delivery systems, encompassing hydrogels and polymer-based approaches.

EXPERT OPINION

Complex laryngotracheal diseases pose challenges for effective treatment, struggling due to the intricate anatomy, limited access, and recurrence. Symptomatic management often requires invasive surgical procedures or medications that are unable to achieve lasting effects. Recent advances in nanotechnology and biocompatible materials provide potential solutions, enabling precise drug delivery, personalization, and extended treatment efficacy. Combining these technologies could lead to groundbreaking treatments for upper airways diseases, significantly improving patients' quality of life. Research and innovation in this field are crucial for further advancements.

Simultaneous High-Speed Video Laryngoscopy and Acoustic Aerodynamic Recordings during Vocal Onset of Variable Sound Pressure Level: A Preliminary Study

Voicing: requires frequent starts and stops at various sound pressure levels (SPL) and frequencies. Prior investigations using rigid laryngoscopy with oral endoscopy have shown variations in the duration of the vibration delay between normal and abnormal subjects. However, these studies were not physiological because the larynx was viewed using rigid endoscopes. We adapted a method to perform to perform simultaneous high-speed naso-endoscopic video while simultaneously acquiring the sound pressure, fundamental frequency, airflow rate, and subglottic pressure. This study aimed to investigate voice onset patterns in normophonic males and females during the onset of variable SPL and correlate them with acoustic and aerodynamic data.

MATERIALS AND METHODS

Three healthy males and three healthy females were studied by simultaneous high-speed video laryngoscopy and recording with the production of the gesture [pa:pa:] at soft, medium, and loud voices. The fiber optic endoscope was threaded through a pneumotachograph mask for the simultaneous recording and analysis of acoustic and aerodynamic data.

RESULTS

The average increase in the sound pressure level (SPL) for the group was 15 dB, from 70 to 85 dB. The fundamental frequency increased by an average of 10 Hz. The flow was increased in two subjects, reduced in two subjects, and remained the same in two subjects as the SPL increased. There was a steady increase in the subglottic pressure from soft to loud phonation. Compared to soft to medium phonation, a significant increase in glottal resistance was observed with medium-to-loud phonation. Videokymogram analysis showed the onset of vibration for all voiced tokens without the need for full glottis closure. In loud phonation, there is a more rapid onset of a larger amplitude and prolonged closure of the glottal cycle; however, more cycles are required to achieve the intended SPL. There was a prolonged closed phase during loud phonation. Fast Fourier transform (FFT) analysis of the kymography waveform signal showed a more significant second- and third-harmonic energy above the fundamental frequency with loud phonation. There was an increase in the adjustments in the pharynx with the base of the tongue tilting, shortening of the vocal folds, and pharyngeal constriction.

CONCLUSION

Voice onset occurs in all modalities, without the need for full glottal closure. There was a more significant increase in glottal resistance with loud phonation than that with soft or middle phonation. Vibration analysis of the voice onset showed that more time was required during loud phonation before the oscillation stabilized to a steady state. With increasing SPL, there were significant variations in vocal tract adjustments. The most apparent change was the increase in tongue tension with posterior displacement of the epiglottis. There was an increase in pre-phonation time during loud phonation. Patterns of muscle tension dysphonia with laryngeal squeezing, shortening of the vocal folds, and epiglottis tilting with increasing loudness are features of loud phonation. These observations show that flexible high-speed video laryngoscopy can reveal observations that cannot be observed with rigid video laryngoscopy. An objective analysis of the digital kymography signal can be conducted in selected cases.

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.

Digital Videokymography: Analysis of Glottal Closure in Adults

INTRODUCTION

High-speed videolaryngoscopy and quantitative analysis of laryngeal images are relevant in accurately diagnosing vocal fold closure patterns.

OBJECTIVE

To analyze the parameters of digital videokymography obtained through high-speed videolaryngoscopy in women and men with complete and incomplete glottal closure, and posterior glottal chink.

METHODS

We conducted an observational, analytical, cross-sectional study with data from 65 adults, which we divided into groups according to sex and glottal closure. Digital videokymography parameters were analyzed using an image-processing program. The Anderson-Darling and Mann-Whitney U tests were used to verify sample normality and compare videokymography parameters between groups, respectively. The significance level was set at 5%.

RESULTS

Among 65 laryngeal images, 20 each were from women with complete and incomplete glottal closure, and 20 and 5 were from men with complete and incomplete glottal closure, respectively. Considering the clinical relevance of the evaluated data, groups of 11 women and 4 men with posterior glottal chink were compared with sex-similar groups with complete glottal closure. Digital videokymography showed a lower maximum and mean vocal fold opening in women with incomplete glottal closure, and a lower dominant left vocal fold-opening amplitude and higher dominant frequency of bilateral vocal fold opening in men with incomplete glottal closure. It also showed a lower closed phase percentage in the posterior region for women and men, with higher closed phase percentage in the anterior and middle regions in women. Both groups with posterior glottal chink showed similar results.

CONCLUSION

Incomplete glottal closure may interfere with the results of the digital videokymography parameters, with higher impact on the posterior vocal fold region in males and the middle and anterior vocal fold regions in females.

Determining the Mouth-to-Microphone Distance in Rigid Laryngoscopy: A Simple Solution Based on the Newly Measured Values of the Depth of Endoscope Insertion into the Mouth

Mouth-to-microphone (MTM) distance is important when measuring the sound of voice. However, determining the MTM distance for laryngoscope-mounted microphones during laryngoscopic examinations is cumbersome. We introduce a novel solution for such cases, using the depth of insertion of the laryngoscope into the mouth DI as a reference distance. We measured the average insertion depth, DI, in 60 adult women and 60 adult men for rigid laryngoscopes with 70° and 90° view. We found the DI for the 70°/90° laryngoscope to be 9.7 ± 0.9/9.4 ± 0.6 cm in men, 8.9 ± 0.9/8.7 ± 0.7 cm in women, and 9.3 ± 0.9/9.0 ± 0.7 cm in all adults. Using these values, we show that, for microphones fixed at 15-40 cm from the tip of the laryngoscope, the final MTM distances are between 5 and 35 cm from the lips, and the standard uncertainties of these distances are between 16% and 2.5%. Our solution allows laryngologists and laryngoscope manufacturers to set and estimate the MTM distance for any rigid laryngeal endoscope with a microphone attached with reasonable accuracy, avoiding the need to measure this distance in vivo in routine practice.

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).

Videokymographic index of glottic function: an analysis of diagnostic accuracy

ABSTRACT Purpose To develop the Videokymographic Index of Glottic Function (VIGF), a composite indicator from digital videokymography parameters, captured by high-speed videolaryngoscopy exams of women with and without laryngeal alterations of behavioral etiology. Methods The sample consisted of 92 women aged between 18 and 45 years. Fifty-five (55) women with behavioral dysphonia, presenting with laryngeal and voice alterations, and thirty-seven (37) women without any laryngeal and voice alterations. Voice evaluation was performed by consensus via an auditory-perceptual analysis of the sustained vowel /a/ at a habitual pitch and loudness. Voice classification was obtained by means of a general degree of dysphonia, where G0 indicated neutral voice quality and G1 to G3 indicated altered voice quality. Laryngeal images were captured via digital videokymography analysis of a sustained vowel /i/ at a habitual pitch and loudness. The VIGF was based on the midpoint of the glottal region for analysis. Logistic regression was performed using the MINITAB 19 program. Results Logistic regression was composed of two stages: Stage 1 consisted of the analysis of all variables, where the maximum opening and closed quotient variables showed statistical significance (p-value <0.05) and the model was well adjusted according to the Hosmer-Lemeshow test (p-value=0.794). Stage 2 consisted of the re-analysis of the selected variables, also showing a well-adjusted model (p-value=0.198). The VIGF was defined as follows: VIGF=e^(8.1318-0.2941AbMax-0.0703FechGlo)/1+e^(8.1318-0.2941AbMax-0.0703FechGlo). Conclusion The VIGF demonstrated a cut-off value equal to 0.71. The probability of success was 81.5%, sensitivity 76.4%, and specificity 89.2%.

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.

Analysis of the Immediate Effects of the LaxVox Technique on Digital Videokymography Parameters in Adults With Voice Complaints

OBJECTIVES

Digital videokymography based on high-speed videoendoscopy enables the evaluation of therapeutic techniques and voice training, such as the LaxVox technique, on vocal fold vibrations. This study investigated the immediate effects of the LaxVox technique on digital videokymographic parameters obtained through high-speed videolaryngoscopy in adults with voice complaints.

STUDY DESIGN

An experimental intrasubject comparative study of adults with voice complaints was conducted.

METHODS

Image processing software was used to analyze the videos and obtain digital videokymography parameters. The intraclass correlation coefficient was used to determine the intra-rater reliability of the analyzed parameters. The paired t test and Wilcoxon signed-rank test were used to compare digital videokymography parameters before and after the LaxVox technique, in sex-specific analyses. The significance level was set at 5%.

RESULTS

In total, 25 laryngeal images from 15 women and 10 men were analyzed. On digital videokymography analysis, the mean vocal fold opening in the posterior glottal region was decreased immediately after using the LaxVox technique in women. In contrast, no significant changes were found in other parameters compared to pre LaxVox technique values in both men and women with voice complaints.

CONCLUSION

Digital videokymography analysis revealed that the LaxVox technique reduces the mean vocal fold opening in the posterior glottal region of women with voice complaints.

Videokymographic index of glottic function: an analysis of diagnostic accuracy

PURPOSE

To develop the Videokymographic Index of Glottic Function (VIGF), a composite indicator from digital videokymography parameters, captured by high-speed videolaryngoscopy exams of women with and without laryngeal alterations of behavioral etiology.

METHODS

The sample consisted of 92 women aged between 18 and 45 years. Fifty-five (55) women with behavioral dysphonia, presenting with laryngeal and voice alterations, and thirty-seven (37) women without any laryngeal and voice alterations. Voice evaluation was performed by consensus via an auditory-perceptual analysis of the sustained vowel /a/ at a habitual pitch and loudness. Voice classification was obtained by means of a general degree of dysphonia, where G0 indicated neutral voice quality and G1 to G3 indicated altered voice quality. Laryngeal images were captured via digital videokymography analysis of a sustained vowel /i/ at a habitual pitch and loudness. The VIGF was based on the midpoint of the glottal region for analysis. Logistic regression was performed using the MINITAB 19 program.

RESULTS

Logistic regression was composed of two stages: Stage 1 consisted of the analysis of all variables, where the maximum opening and closed quotient variables showed statistical significance (p-value <0.05) and the model was well adjusted according to the Hosmer-Lemeshow test (p-value=0.794). Stage 2 consisted of the re-analysis of the selected variables, also showing a well-adjusted model (p-value=0.198). The VIGF was defined as follows: VIGF=e^(8.1318-0.2941AbMax-0.0703FechGlo)/1+e^(8.1318-0.2941AbMax-0.0703FechGlo).

CONCLUSION

The VIGF demonstrated a cut-off value equal to 0.71. The probability of success was 81.5%, sensitivity 76.4%, and specificity 89.2%.

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.

A Deep Learning Enhanced Novel Software Tool for Laryngeal Dynamics Analysis

Purpose High-speed videoendoscopy (HSV) is an emerging, but barely used, endoscopy technique in the clinic to assess and diagnose voice disorders because of the lack of dedicated software to analyze the data. HSV allows to quantify the vocal fold oscillations by segmenting the glottal area. This challenging task has been tackled by various studies; however, the proposed approaches are mostly limited and not suitable for daily clinical routine. Method We developed a user-friendly software in C# that allows the editing, motion correction, segmentation, and quantitative analysis of HSV data. We further provide pretrained deep neural networks for fully automatic glottis segmentation. Results We freely provide our software Glottis Analysis Tools (GAT). Using GAT, we provide a general threshold-based region growing platform that enables the user to analyze data from various sources, such as in vivo recordings, ex vivo recordings, and high-speed footage of artificial vocal folds. Additionally, especially for in vivo recordings, we provide three robust neural networks at various speed and quality settings to allow a fully automatic glottis segmentation needed for application by untrained personnel. GAT further evaluates video and audio data in parallel and is able to extract various features from the video data, among others the glottal area waveform, that is, the changing glottal area over time. In total, GAT provides 79 unique quantitative analysis parameters for video- and audio-based signals. Many of these parameters have already been shown to reflect voice disorders, highlighting the clinical importance and usefulness of the GAT software. Conclusion GAT is a unique tool to process HSV and audio data to determine quantitative, clinically relevant parameters for research, diagnosis, and treatment of laryngeal disorders. Supplemental Material https://doi.org/10.23641/asha.14575533.

High speed digital videolaringoscopy: evaluation of vocal nodules and cysts in women

PURPOSE

To evaluate and compare the parameters of Digital kymography obtained through the High-speed Videolaryngoscopy of women without laryngeal disorders, of women with vocal fold nodules and of women with vocal cysts.

METHODS

A cross-sectional observational study in which 60 women aged 18 years and 45 years were selected. Three study groups were formed: 20 women without laryngeal disorder forming the control group (Group 1), 20 women with diagnosis of vocal fold nodules forming Group 2 and 20 women with diagnosis of vocal cysts forming Group 3. Subsequently the participants were evaluated by High-speed Videolaryngoscopy for analysis and comparison of laryngeal images using Digital kymography. The laryngeal parameters processed by the program KIPS® were: minimum, maximum and mean opening; dominant amplitude of the left and right vocal folds; dominant frequency of the right and left vocal folds; and close.

RESULTS

The analysis of Digital kymography suggests that the presence of the vocal fold nodules and the vocal cysts tend to restrict more to the maximum and minimum opening of the vocal fold and the dominant amplitude of the opening variation in the middle region of the glottis.

CONCLUSION

Digital kymography parameters were similar in the presence of vocal fold nodules and vocal cysts lesions.

Biomechanical Models to Represent Vocal Physiology: A Systematic Review

Biomechanical modeling allows obtaining information on physical phenomena that cannot be directly observed. This study aims to review models that represent voice production. A systematic review of the literature was conducted using PubMed/Medline, SCOPUS, and IEEE Xplore databases. To select the papers, we used the protocol PRISMA Statement. A total of 53 publications were included in this review. This article considers a taxonomic classification of models found in the literature. We propose four categories in the taxonomy: (1) Models representing the Source (Vocal folds); (2) Models representing the Filter (Vocal Tract); (3) Models representing the Source - Filter Interaction; and (4) Models representing the Airflow - Source Interaction. We include a bibliographic analysis with the evolution of the publications per category. We provide an analysis of the number as well of publications in journals per year. Moreover, we present an analysis of the term occurrence and its frequency of usage, as found in the literature. In each category, different types of vocal production models are mentioned and analyzed. The models account for the analysis of evidence about aerodynamic, biomechanical, and acoustic phenomena and their correlation with the physiological processes involved in the production of the human voice. This review gives an insight into the state of the art related to the mathematical modeling of voice production, analyzed from the viewpoint of vocal physiology.

Pre- and post-operative high-speed videolaryngoscopy in unilateral vocal cord paralysis following autologous fat augmentation

PURPOSE

To compare high-speed videolaryngoscopy (HSV) parameters such as open quotient (OQ), amplitude symmetry index (ASI), phase symmetry index (PSI), and frequency symmetry index (FSI), of the unilateral vocal cord paralysis (UVCP) patients pre and post (after 6 months) autologous fat augmentation.

MATERIALS AND METHODS

This retrospective study evaluated all age and gender patients with UVCP that underwent autologous fat augmentation from July 2016 to July 2019. The OQ, ASI, PSI, and FSI were calculated from the HSV recordings by using the montage and fast Fourier transform point analysis. The pre-and post-operative means were compared using a paired student t-test, with a p-value less than 0.05 considered significant.

RESULT

A total of 37 patients, age 41.2 ± 11.3 years (21 to 67 years), 59.4% females and 40.6% males, were included in the study. The average duration of symptom onset was 2.3 ± 0.87 months. The post-operative mean values of OQ, ASI, PSI, and FSI following the fat augmentation were significantly improved compared to the pre-operative mean values with p-values <0.0001, 0.0018, 0.0011, and 0.0006, respectively.

CONCLUSION

There was a significant improvement in the OQ, ASI, PSI, and FSI in UVCP patients after 6 months of autologous fat augmentation, signifying an enhanced vibratory function. The ability of HSV to measure the minute details of vocal cord vibration by providing quantitative measurements has also been highlighted. The need for future prospective research with an increased sample size and longer duration of follow up is recommended.

High-speed videolaryngoscopy in early glottic carcinoma patients following transoral CO2 LASER cordectomy

PURPOSE

To compare high-speed videolaryngoscopy (HSV) findings, like open quotient (OQ), vocal fold vibratory onset delay (VFVOD), amplitude symmetry index (ASI) and phase symmetry index (PSI), after 6 months of cordectomy with that after 1 year, and to compare later with the control group.

METHODS

Retrospective analysis of HSV recordings of 33 patients of early glottic carcinoma after cordectomy was performed after 6 months and 1 year of cordectomy with the help of videokymogram and digital kymogram. The control group of ten individuals was selected from patients who came to hospital with complaints other than larynx. The comparison was done for different types of cordectomy separately.

RESULTS

The mean of OQ, VFVOD, ASI and PSI was found to be significantly higher after 6-month follow-up than after 1-year follow-up, the later was in turn found to be significantly higher than that of the control group, for type II and III cordectomy. The mean of OQ, VFVOD, ASI and PSI for other types of cordectomy also showed similar results, but the significance was not calculated due to less sample size.

CONCLUSION

There was significant improvement in OQ, VFVOD, PSI and ASI following CO₂ LASER cordectomy after 1 year of follow-up, making it a good management option for early glottic carcinoma. The ability of the HSV to measure variations in the vocal cord vibration, following cordectomy, was well established by this study.

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.

Intersegmenter Variability in High-Speed Laryngoscopy-Based Glottal Area Waveform Measures

OBJECTIVES/HYPOTHESIS

High-speed videoendoscopy (HSV) has potential to objectively quantify vibratory vocal fold characteristics during phonation. Glottal Analysis Tools (GAT) version 2018, developed in Erlangen, Germany, is software for determining various glottal area waveform (GAW) quantities. Before having GAT analyze HSV videos, segmenters have to define glottis manually across videos in a semiautomatic segmentation protocol. Such interventions are hypothesized to induce variability of subsequent GAW measure computation across segmenters and may attenuate GAT measures' reliability to a certain point. This study explored intersegmenter variability in GAT's GAW measures based on semiautomatic image processing.

STUDY DESIGN

Cohort study of rater reliability.

METHODS

In total, 20 HSV videos from normophonic and dysphonic subjects with various laryngeal disorders were selected for this study and segmented by three trained segmenters. They separately segmented glottis areas in the same frame sets of the videos. Upon analysis of GAW, GAT offers 46 measures related to topologic GAW dynamic characteristics, GAW periodicity and perturbation characteristics, and GAW harmonic components. To address GAT's reliability, intersegmenter-based variability in these measures was examined with intraclass correlation coefficient (ICC).

RESULTS

In general, ICC behavior of the 46 GAW measures across three raters was highly acceptable. ICC of one parameter was moderate (0.5 < ICC < 0.75), good for seven parameters (0.75 < ICC < 0.9), and excellent for 38 parameters (0.9 < ICC).

CONCLUSIONS

Overall, high ICC values confirm clinical applicability of GAT for objective and quantitative assessment of HSV. Small intersegmenter differences with actual small parameter differences suggest that manual or semiautomatic segmentation in GAT does not noticeably influence clinical assessment outcome. To guarantee the software's performance, we suggest segmentation training before clinical application.

LEVEL OF EVIDENCE

2b Laryngoscope, 130:E654-E661, 2020.

Outcome Analysis of Microlaryngeal Surgery for Benign Lesions of Vocal Cord Using Videostroboscopy and Voice Handicap Index

Benign vocal cord mass lesions are common causes of dysphonia which are often surgically correctable. They include lesions like vocal polyps, vocal cysts, vocal nodules and Reinke's edema. A prospective study of 30 patients was carried out at SMS medical college and hospital between April 2014 to November 2015 after institutional ethical committee clearance. The purpose of our study was to evaluate outcome of microlaryngeal surgery for benign lesions of vocal cord using videostroboscopy and voice handicap index. All cases between the age group 15-60 years with clinical evidence of benign lesions of vocal cord were included in study. Preoperative amplitude, mucosal wave, glottic closure was seen by videostroboscopy and subjective assessment of severity of handicap in voice was assessed by set of questionnaire using voice handicap index (Jacobson et al. in Am J Speech Lang Pathol 6: 66-70, 1997). Postoperative follow up was done at 3rd week and 10th week, and outcome of microlaryngeal surgery was assessed using videostroboscope and voice handicap index. At the end of study data was compiled systemically and analysed using paired 't' test and Chi square test. Our study observed statistically significant improvement in amplitude and mucosal wave and glottic closure. Subjective improvement in perception of severity of handicap in voice was analysed by voice handicap index which shows statistically significant data. Overall our study conclude microlaryngeal surgery as an effective way for improvement in speech parameters, that can be assessed by use of videostroboscopy and voice handicap index.

Reliability of High-speed Videoendoscopic Ratings of Essential Voice Tremor and Adductor Spasmodic Dysphonia

OBJECTIVES

The main objectives of this study were to (1) examine intrarater and inter-rater reliabilities in perceptual ratings of vocal fold vibratory patterns and supraglottic characteristics for essential vocal tremor and adductor spasmodic dysphonia (AdSD) using high-speed videoendoscopy (HSV), and (2) to investigate the specificity of the parameters in differentiating these two voice disorders.

METHODS

HSV recordings of 34 cases diagnosed with essential vocal tremor, AdSD, or AdSD with vocal tremor were evaluated blindly by two voice speech pathologists. The two raters examined all HSV video segments twice across nine supraglottic and vocal fold vibratory characteristics for inter-rater and intrarater reliabilities. A separate consensus rating was then developed, with the results analyzed to explore differentiation.

RESULTS

Raters demonstrated moderate intrarater reliability with mean Spearman's rho correlation coefficients of 0.68 (rater 1) and 0.73 (rater 2). Moderate inter-rater reliability for the two raters was seen across all parameters with a mean Cohen's kappa coefficient of 0.51. Raters showed higher intrarater and inter-rater reliabilities for supraglottic parameters. Only the presence of tremor differentiated between the two voice disorders in cases with a consistent diagnosis.

CONCLUSIONS

The high level of concomitance between vocal tremor and AdSD may affect subjective perceptual analysis of supraglottic and vocal fold vibratory patterns. Results indicate similar global involvement of supraglottic laryngeal structures for both vocal tremor and AdSD.

Investigation of Flexible High-Speed Video Nasolaryngoscopy

OBJECTIVE

High-speed videolaryngoscopy is widely used in voice practices as a complement to videostroboscopy, especially when it is desired to visualize asymmetric and nonperiodic vocal fold vibration or voice onset and offset. Because of the requirement for greater illumination at higher frame rates, the high-speed exam is usually performed with a rigid transoral laryngoscope. Although it is possible to obtain color high-speed video images with a flexible fiberoptic nasoendoscope, the results are often disappointing because of the inability to provide adequate lighting inside the larynx. This paper will present the results of a systematic exploration of tools and techniques to optimize the image brightness of flexible color high-speed videolaryngoscopy exams using the KayPENTAX Model 9710 Color High-Speed Video (CHSV) System.

METHODS

The KayPENTAX CHSV System was used with three PENTAX flexible fiberoptic nasolaryngoscopes and a new supplemental light fiber bundle to perform high-speed examinations of healthy vocal folds. Variables of the investigation included camera frame rate, camera sensitivity (color head versus black-and-white head), optics (camera lens focal length), light coupling, nasoendoscope outer diameter, and endoscopy technique (visually perceived distance of the distal tip of scope from the glottal plane).

RESULTS AND CONCLUSIONS

The manipulation of camera gain, the proper selection of lens coupler focal length, and the adjustment of scope distal tip distance from the glottal plane were found to be most effective for optimizing image brightness, whereas the supplemental light fiber bundle provided minimal benefits. Other factors considered include patient comfort, practicality, and ease of use by the clinician.

Characterization of Vocal Fold Vibration in Sulcus Vocalis Using High-Speed Digital Imaging

PURPOSE

The aim of the present study was to qualitatively and quantitatively characterize vocal fold vibrations in sulcus vocalis by high-speed digital imaging (HSDI) and to clarify the correlations between HSDI-derived parameters and traditional vocal parameters.

METHOD

HSDI was performed in 20 vocally healthy subjects (8 men and 12 women) and 41 patients with sulcus vocalis (33 men and 8 women). Then HSDI data were evaluated by assessing the visual-perceptual rating, digital kymography, and glottal area waveform.

RESULTS

Patients with sulcus vocalis frequently had spindle-shaped glottal gaps and a decreased mucosal wave. Compared with the control group, the sulcus vocalis group showed higher open quotient as well as a shorter duration of the visible mucosal wave, a smaller speed index, and a smaller glottal area difference index ([maximal glottal area - minimal glottal area]/maximal glottal area). These parameters deteriorated in order of the control group and Type I, II, and III sulcus vocalis. There were no gender-related differences. Strong correlations were noted between the open quotient and the type of sulcus vocalis.

CONCLUSIONS

HSDI was an effective method for documenting the characteristics of vocal fold vibrations in patients with sulcus vocalis and estimating the severity of dysphonia.