Mucosal wave measurement and visualization techniques

Scale for the assessment of mucosal wave dynamics of the free edges during stroboscopic examination: clinical validation study and analysis of results

INTRODUCTION

Identifying the mucosal wave (MW) is essential when studying the voice; however, its characterization and perceived measurement during laryngeal stroboscopy (LS) are not well defined or standardized because of the subjectivity of its interpretation. This article proposed and validated a scale that characterized and approximated MW measurement during LS, applied it to participants divided into a healthy group and groups with free edge conditions, and identified differences between them.

METHODS

This is a descriptive and clinical validation study of the "VASQ (Vertical axis, Anteroposterior axis, Symmetry and Quantity) mucosal wave score" scale based on stroboscopy images of 137 adult men and women divided into a control group and functional and organic pathology groups. The images were analyzed by three evaluators according to an established protocol. Measurements dictating the reproducibility and validity criteria as well as the MW score in each group were obtained.

RESULTS

The reliability of the scale was α = 0.90, internal consistency success rate was 91%, intra-observer reliability was 0.83, inter-observer reliability was 0.83, content validity coefficient was 0.92, and factor loading was 0.37-0.53. The MW total score values between 5 and 6 were established as a reference for normality (P < 0.05). Organic pathology showed lower MW score values (P < 0.05), and functional pathology to a lesser extent (P > 0.05).

CONCLUSIONS

The proposed scale is a consistent, valid, and reliable tool. Its widespread application would favor commonly used terminology and facilitate quantitative comparisons in future studies.

Characterization of the Vertical Stiffness Gradient in Cadaveric Human and Excised Canine Larynges

The elastic properties of the folds govern the characteristics of vocal fold vibrations. This study addresses existing gaps by investigating the Young's modulus along the anterior-posterior direction in excised canine and cadaveric human vocal folds. Micro-indentation testing was conducted on six excised canines and three cadaveric human larynges. Multiple points along the medial glottal wall were indented to determine force-displacement, stress-strain relationships, and Young's modulus as a function of Green's strain. A vertical stiffness gradient was consistently observed in both canine and human samples, with higher stiffness in the inferior aspect compared with the superior aspect. The stiffness increased toward both the anterior and posterior directions from the mid-coronal plane, with a more pronounced increase at the posterior edge. Human vocal folds generally exhibited lower stiffness at low strains but were comparable to canine vocal folds at higher strains. These findings suggest that the canine larynx model is a reasonable representation of the human laryngeal tissues' elastic property trends. This analysis of the vertical stiffness gradient in canine and human vocal folds provides valuable data for improving experimental and numerical models of phonation.

Automatic Segmentation of Membranous Glottal Gap Area with U-Net-Based Architecture

BACKGROUND

While videostroboscopy is recognized as the most popular approach for investigating vocal fold function, evaluating the numerical values, such as the membranous glottal gap area, remains too time consuming for clinical applications.

METHODS

We used a total of 2507 videostroboscopy images from 137 patients and developed five U-Net-based deep-learning image segmentation models for automatic masking of the membranous glottal gap area. To further validate the models, we used another 410 images from 41 different patients.

RESULTS

During development, all five models exhibited acceptable and similar metrics. While the VGG19 U-Net had a long inference time of 1654 ms, the other four models had more practical inference times, ranging from 16 to 138 ms. During further validation, Efficient U-Net demonstrated the highest intersection over union of 0.8455, the highest Dice coefficient of 0.9163, and the lowest Hausdorff distance of 1.5626. The normalized membranous glottal gap area index was also calculated and validated. Efficient U-Net and VGG19 U-Net exhibited the lowest mean squared errors (3.5476 and 3.3842) and the lowest mean absolute errors (1.8835 and 1.8396).

CONCLUSIONS

Automatic segmentation of the membranous glottal gap area can be achieved through U-net-based architecture. Considering the segmentation quality and speed, Efficient U-Net is a reasonable choice for this task, while the other four models remain valuable competitors. The models' masked area enables possible calculation of the normalized membranous glottal gap area and analysis of the glottal area waveform, revealing promising clinical applications for this model.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:2835-2843, 2024.

Histologic Examination of Vocal Fold Mucosal Wave and Vibration

OBJECTIVES

Despite gross anatomic and histologic differences between human and canine vocal folds, similar wave patterns have been described yet not fully characterized. We reconstructed vocal fold (VF) vibration in a canine hemilarynx and performed histologic examination of the same vocal fold. We demonstrate comparable wave patterns while exploring the importance of certain anatomic architectures.

METHODS

An in vivo canine hemilarynx was phonated against a glass prism at low and high muscle activation conditions. Vibration was captured using high-speed video, and trajectories of VF medial surface tattooed landmarks were 3D-reconstructed. The method of empirical eigenfunctions was used to capture the essential dynamics of vibratory movement. Histologic examination of the hemilarynx was performed.

RESULTS

Oscillation patterns were highly similar between the in vivo canine and previous reports of ex vivo human models. The two most dominant eigenfunctions comprised over 90% of total variance of movement, representing opening/closing and convergent/divergent movement patterns, respectively. We demonstrate a vertical phase difference during the glottal cycle. The time delay between the inferior and superior VF was greater during opening than closing for both activation conditions. Histological examination of canine VF showed not only a thicker lamina propria layer superiorly but also a distinct pattern of thyroarytenoid muscle fibers and fascicles as described in human studies.

CONCLUSIONS

Histologic and vibratory examination of the canine vocal fold demonstrated human vocal fold vibratory patterns despite certain microstructural differences. This study suggests that the multilayered lamina propria may not be fundamental to vibratory patterns necessary for human-like voice production.

LEVEL OF EVIDENCE

NA (Basic science study) Laryngoscope, 134:264-271, 2024.

Nasal Breathing Through a Damp Gauze Enhances Surface Hydration of the Vocal Folds and Optimizes Vocal Function

OBJECTIVE

The present study proposes a direct surface hydration system based on nasal breathing through a damp gauze. The goal is to observe whether such direct hydration procedure positively modifies vocal fold functionality by improving voice quality and enhancing the mobility and pliability of the vocal fold mucosa.

METHODS

Sixty-one young adults without voice problems were enrolled and were randomly divided into three double-blinded treatment groups. In the first group (the gauze group), participants breathed through the nose wrapped in a damp gauze for 10 minutes while doing vocal warm-up exercises to facilitate water penetration into the mucosal layers of the vocal folds. The second group (the exercise group) performed the same warm-up exercises as the gauze group for 10 minutes without hydration procedures. The third group (the control group) talked using their normal speaking voice for 10 minutes. The participants were evaluated before and after the treatment tasks with three tests: a laryngostroboscopic examination (ie, the glottic closure, the amplitude of the mucosal wave, and the maximum opening of the glottic space); voice acoustic analysis (multidimensional voice program); and a perceptual voice evaluation (GRBAS scale).

RESULTS

Results showed that after the use of a damp gauze, glottic closure, the amplitude of the mucosal wave, the maximum opening of the glottic space, the shimmer, and the B of GRBAS all improved.

CONCLUSION

Findings showed significantly better vocal results for the participants of the gauze group, suggesting the damp gauze procedure to be an effective, fast, and economical procedure to improve and optimize vocal fold functionality. It can be hypothesized that the obtained results are related to an improvement in vocal folds surface hydration and viscoelasticity.

Comparison between the acoustic fundamental frequency of the voice and the vibration frequency of the vocal folds analyzed by digital kymography

PURPOSE

To compare the frequency of vocal fold opening variation, analyzed by digital kymography, with the fundamental voice frequency obtained by acoustic analysis, in individuals without laryngeal alteration.

METHODS

Observational analytical cross-sectional study. The participants were forty-eight women and 38 men from 18 to 55 years of age. The evaluation was made by voice acoustic analysis, by the habitual emission of the vowel /a/ for 3 seconds, and days of the week, and digital kymography (DKG), by the habitual emission of the vowels /i/ and /ɛ/. The measurements analyzed were acoustic fundamental frequency (f0), extracted by the Computerized Speech Lab (CSL) program, and dominant frequency of the variation of right (R-freq) and left (L-freq) vocal fold opening, obtained through the KIPS image processing program. The mounting of the kymograms consisted in the manual demarcation of the region by vertical lines delimiting width and horizontal lines separating the posterior, middle and anterior thirds of the Rima glottidis. In the statistical analysis, the Anderson-Darling test was used to verify the normality of the sample. The ANOVA and Tukey tests were performed for the comparison of measurements between the groups. For the comparison of age between the groups, the Mann-Whitney test was used.

RESULTS

There are no differences between the values of the frequency measurement analyzed by digital kymography, with the acoustic fundamental frequency, in individuals without laryngeal alteration.

CONCLUSION

The values of the dominant frequency of the vocal folds opening variation, as assessed by digital kymography, and the acoustic fundamental frequency of the voice are similar, allowing comparison between these measurements in the multidimensional evaluation of the voice, in individuals without laryngeal alteration.

Real-time detection of laryngopharyngeal cancer using an artificial intelligence-assisted system with multimodal data

BACKGROUND

Laryngopharyngeal cancer (LPC) includes laryngeal and hypopharyngeal cancer, whose early diagnosis can significantly improve the prognosis and quality of life of patients. Pathological biopsy of suspicious cancerous tissue under the guidance of laryngoscopy is the gold standard for diagnosing LPC. However, this subjective examination largely depends on the skills and experience of laryngologists, which increases the possibility of missed diagnoses and repeated unnecessary biopsies. We aimed to develop and validate a deep convolutional neural network-based Laryngopharyngeal Artificial Intelligence Diagnostic System (LPAIDS) for real-time automatically identifying LPC in both laryngoscopy white-light imaging (WLI) and narrow-band imaging (NBI) images to improve the diagnostic accuracy of LPC by reducing diagnostic variation among on-expert laryngologists.

METHODS

All 31,543 laryngoscopic images from 2382 patients were categorised into training, verification, and test sets to develop, validate, and internal test LPAIDS. Another 25,063 images from five other hospitals were used as external tests. Overall, 551 videos were used to evaluate the real-time performance of the system, and 200 randomly selected videos were used to compare the diagnostic performance of the LPAIDS with that of laryngologists. Two deep-learning models using either WLI (model W) or NBI (model N) images were constructed to compare with LPAIDS.

RESULTS

LPAIDS had a higher diagnostic performance than models W and N, with accuracies of 0·956 and 0·949 in the internal image and video tests, respectively. The robustness and stability of LPAIDS were validated in external sets with the area under the receiver operating characteristic curve values of 0·965-0·987. In the laryngologist-machine competition, LPAIDS achieved an accuracy of 0·940, which was comparable to expert laryngologists and outperformed other laryngologists with varying qualifications.

CONCLUSIONS

LPAIDS provided high accuracy and stability in detecting LPC in real-time, which showed great potential for using LPAIDS to improve the diagnostic accuracy of LPC by reducing diagnostic variation among on-expert laryngologists.

An Exploration of the Risk Factors, Severity, and Sequelae of Vocal Fold Hemorrhage in a Population of Voice Patients Before and After Diagnosis

BACKGROUND

Vocal fold hemorrhage (VFH) is the rupture (usually acute) of a blood vessel within the true vocal fold. The long-term sequelae of VFH on the mucosal wave (MW) and glottic gap on video stroboscopy remain understudied. The primary objective of this study was to investigate the short-term and long-term consequences of VFH through measured and rated analysis of the mucosal wave and glottic gap.

METHODS

The presence of VFH and its extent (limited/moderate vs. extensive VFH) were identified. The primary outcome of this study was mucosal wave, which was assessed on an ordinal scale by three blinded raters pre and posthemorrhage. Only patients who had undergone strobovideolaryngoscopy before sustaining VFH were included. Mucosal wave and glottic gap also were measured using image pixel analysis using the open-access tool, ImageJ (NIH, Bethesda, MD).

RESULTS

Twenty-three subjects were included in this study (mean age 39.78 ± 15.54). Intra-rater reliability for MW ratings was 81.48% ± 6.150% (minimum 77.78%) for all evaluators (κ = 0.519 [0.267-0.772], P < 0.001). Inter-rater reliability analysis revealed 75.56% agreement between evaluators (κ = 0.524 [0.425-0.623], P < 0.001). MWMeasured extrapolated from ImageJ methodology correlated significantly with MWRated (n = 70, r = 0.448, P < 0.001). ΔMWMeasured from baseline to follow-up evaluation were compared for both the initial follow-up visit (FU1) and the second follow-up visit (FU2) [-4.135 ± 31.01 vs. 36.50 ± 39.97, P = 0.025]. Hence, ΔMWMeasured was significantly better by FU2 than FU1, with the larger positive change from baseline representing a greater improvement in the measured mucosal wave. Additionally, there were significant differences in ΔMWRated between those with limited/moderate VFH and those with extensive VFH at FU1. Duration of absolute voice rest correlated significantly with time to VFH resolution. Long-term change in mucosal wave after hemorrhage was assessed using both ΔMWMeasured and MWRated. Based on ΔMWRater, 35.0% of subjects demonstrated ongoing and worse mucosal wave restriction compared to baseline at their most recent follow-up visit. Based on ΔMWMeasured, 50.0% of the subjects showed ongoing and worse mucosal wave restriction compared to baseline at their most recent follow-up visit.

CONCLUSION

Overall long-term restrictions in MW after hemorrhage were present in 35.0% of the subjects based on ratings and 50.0% of the patients based on the measured MW using ImageJ, demonstrating the importance of ongoing study into this pathology and how to prevent it, especially in PVU and professional singers. Patients presenting with extensive hemorrhage were at risk for more prominent, detectable changes in mucosal wave compared to those with limited/moderate hemorrhage in the short-term, defined by a mean FU time of 3 months, but not long-term, characterized by a mean FU time 6 months or greater. Whether the severity of VFH is a true indicator of mucosal wave alterations requires additional study, as does the reliability and validity of ImageJ mucosal wave and glottic gap measurement techniques.

5-Fluorouracil for Treatment of Vocal Fold Scar

BACKGROUND

Vocal fold (VF) scar can result from trauma, neoplasm, inflammatory processes, congenital causes, surgery and other etiologies. In general, once the vibratory margin of the VF has been scarred, it has not been possible to return VF function to normal; but often it can be improved. The drug 5-fluorouracil (5-FU) is a pyrimidine antimetabolic that has many clinical applications ranging from systemic chemotherapy to topical treatment of actinic keratosis and basal cell carcinoma of the skin. Local injection with 5-FU also has been used for hypertrophic scar and keloids. 5-FU was shown to have benefit in animal models of VF scar and subglottic stenosis.

OBJECTIVES

The present study aimed to evaluate the effect of 5-FU injection on VF vibratory function in patients with VF scar. Outcomes of 5-FU injection were compared to controls injected with dexamethasone.

METHODS

Adult voice center patients who had undergone VF injection with dexamethasone or a series of three 5-FU injections for treatment of VF scar were included in the study. Postoperative outcomes included percentage of subjects demonstrating improvement after injection, change in scar size, glottic closure, and VF stiffness, as well as digital image analysis measurements of mucosal wave. Outcomes were compared between subjects who received 5-FU and those who received dexamethasone.

RESULTS

There were 58 VFs injected with 5-FU and 58 historical controls injected with dexamethasone. Baseline subject characteristics and etiology of scar did not differ significantly between the 5-FU and dexamethasone cohorts, except that scar size was greater in the 5-FU group and mucosal wave was worse at baseline. After a series of three 5-FU injections, 61.22% improved, 8.16% demonstrated no change, and 30.61% worsened. In the dexamethasone cohort, 51.06% improved, 0.00% demonstrated no change, and 48.94% worsened. The response differed significantly between the 5-FU and dexamethasone cohorts, with a greater proportion of subjects who underwent 5-FU injection demonstrating improvement postoperatively. In the 5-FU cohort, 32.76% of subjects previously had undergone and failed dexamethasone injection for VF scar: and within that group 84.21% improved, 5.26% demonstrated no change, and 10.53% worsened following 5-FU injection. On digital image analysis, the percent improvement in postoperative mucosal wave was significantly greater in the 5-FU cohort compared to the dexamethasone group, which demonstrated a worsening of mucosal wave.

CONCLUSIONS

A series of three intralesional injections with 5-FU outperformed dexamethasone for improving mucosal wave in patients with VF scar. A prior failed trial of dexamethasone injection predicted a favorable response to 5-FU. Further research is encouraged to confirm or refute these findings.

Postoperative Voice Surgical Outcomes in Professional Singers vs Non-Singers

OBJECTIVES

Professional singers often are described as vocal athletes, and just as professional athletes get injured, injuries to professional singers can occur during practice and performances. In other fields of medicine, research has shown that competitive sports athletes recover more quickly after orthopedic surgical procedures compared to non-athletes. The purpose of this study was to determine whether similar differences occur with voice patients by comparing voice surgical outcomes between professional singers and non-singers.

METHODS

A retrospective cohort study was conducted that included a consecutive sample of 194 adult subjects who underwent voice surgical procedures in the operating room. All surgeries were performed by the same surgeon, the senior author of this study (RTS). Data were reviewed for patients with medical records between January 1, 2010 to February 1, 2022. Subjects who reported receiving income from singing or reported studying voice at a collegiate level or higher were classified as professional singers. Subjects reporting careers in all other professions, including unpaid avocational singers or singers without formal training, were assigned to the non-singer control group. The data were analyzed using SPSS statistical software. Statistical significance was determined using independent samples t test for continuous variables and Fisher's exact test or binary logistic regression for binary outcomes.

RESULTS

There were 194 subjects included in this study (43.81% male/56.19% female). The average age was 42.60 ± 15.17. Ninety subjects were professional singers and 104 were non-singers. Revision of surgical plan was significantly different for professional singers compared to non-singers (14.44% versus 0%, P < 0.001). The rate of postoperative complications did not differ significantly between the singer and non-singer groups, even when adjusting for other factors. Professional singers presented with slightly more severe vocal fold hemorrhages on the first postoperative visit compared to non-singers (1.73 ± 0.73 versus 1.32 ± 0.65, P = 0.003), but there was no difference by the second visit. Following surgery, professional singers adhered to a longer duration of voice rest. However, both groups participated equally in voice therapy postoperatively.

CONCLUSIONS

No differences were found in operative complications between professional singers and non-singers. This study describes outcomes and considerations in patient care for professional singers. It also provides insight into potentially modifiable factors, such as voice rest, that could impact patient care postoperatively.

Biometric imaginaries: Formatting voice, body, identity to data

This article examines the sociotechnical imaginary within which contemporary biometric listening or VIA (voice identification and analysis) technologies are being developed. Starting from an examination of a key article on Voiceprint identification written in the 1940s, I interrogate the conceptual link between voice, body, and identity, which was central to these early attempts at technologizing voice identification. By surveying patents that delineate systems for voice identification, collection methods for voice data, and voice analysis, I find that the VIA industry is dependent on the conceptual affixion of voice to identity based on a reduction of voice that sees it as a fixed, extractable, and measurable 'sound object' located within the body. This informs the thinking of developers in the VIA industry, resulting in a reframing of the technological shortcomings of voice identification under the rubric of big data. Ultimately, this reframing rationalizes the implementation of audio surveillance systems into existing telecommunications infrastructures through which voice data is acquired on a massive scale.

Application of the HRES 5562 Camera Using the HSDI Technique in the Diagnosis of Glottal Insufficiencies in Teachers

OBJECTIVE

Teachers are the largest group of professional voice users with predispositions to functional or organic changes in the larynx. The dysfunction of intrinsic muscles of the larynx frequently occurs which leads to changes in parameters of quality of voice (dysphonia). The aim of the study is the assessment of parameters of vocal folds vibrations, Mucosal Wave morphology, Glottal Closure Type and Open Quotient (OQ) using High Speed (HS) camera and High Speed Digital Imaging (HSDI) technique in teachers with disorders of voice quality classified in GRBAS scale in glottal insufficiencies.

MATERIAL AND METHOD

The study included group of 50 teachers of both genders, working in primary and secondary education units for 15 years, without systemic diseases with disorders of quality of voice confirmed by the results in GRBAS scale assessment. Vocal folds vibrations were assessed with HS camera by R. Wolf and HSDI technique. Rigid endoscope with 90^o optics by the same company was used in the study. Vocal folds vibrations were registered with the speed of 4000 frames/sec. Regularity, symmetry of vibrations, Mucosal Wave (MW) morphology as well as Glottal Closure Type were assessed. Numerical value of OQ was determined in anterior, middle and posterior segment of the glottis during phonation.

RESULTS

Assessment of real vibrations of vocal folds revealed irregularity, mean asymmetry of vibrations, MW reduction as well as glottal insufficiency, the most frequently (96%), in the middle segment - type E according to European Laryngological Society, less frequently (4%) - type E+C. The highest value of OQ (average 0.98) was registered in the middle segment of the glottis. In GRBAS scale, significant dysphonia has been registered, classified as G₃R₃B₃A₃ without the features of voice strain - S₀.

CONCLUSION

In group of teachers with extensive professional experience, glottal insufficiency in the middle segment was registered the most frequently which was confirmed by high values of OQ in this region obtained with HSDI technique. What is more, irregularity, mean asymmetry and asynchrony of vibrations with MW reduction were registered which confirmed the existence of glottal insufficiency in this group. GRBAS scale was useful in preliminary evaluation of dysphonia and its severity, however, the diagnosis of its clinical form was possible only with visualization of the larynx and objective parameters obtained with HSDI.

Artificial Intelligence in Laryngeal Endoscopy: Systematic Review and Meta-Analysis

Background: Early diagnosis of laryngeal lesions is necessary to begin treatment of patients as soon as possible to preserve optimal organ functions. Imaging examinations are often aided by artificial intelligence (AI) to improve quality and facilitate appropriate diagnosis. The aim of this study is to investigate diagnostic utility of AI in laryngeal endoscopy. Methods: Five databases were searched for studies implementing artificial intelligence (AI) enhanced models assessing images of laryngeal lesions taken during laryngeal endoscopy. Outcomes were analyzed in terms of accuracy, sensitivity, and specificity. Results: All 11 studies included presented an overall low risk of bias. The overall accuracy of AI models was very high (from 0.806 to 0.997). The accuracy was significantly higher in studies using a larger database. The pooled sensitivity and specificity for identification of healthy laryngeal tissue were 0.91 and 0.97, respectively. The same values for differentiation between benign and malignant lesions were 0.91 and 0.94, respectively. The comparison of the effectiveness of AI models assessing narrow band imaging and white light endoscopy images revealed no statistically significant differences (p = 0.409 and 0.914). Conclusion: In assessing images of laryngeal lesions, AI demonstrates extraordinarily high accuracy, sensitivity, and specificity.

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.

Surface kinematic and depth-resolved analysis of human vocal folds in vivo during phonation using optical coherence tomography

SIGNIFICANCE

The human vocal fold (VF) oscillates in multiple vectors and consists of distinct layers with varying viscoelastic properties that contribute to the mucosal wave. Office-based and operative laryngeal endoscopy are limited to diagnostic evaluation of the VF epithelial surface only and are restricted to axial-plane characterization of the horizontal mucosal wave. As such, understanding of the biomechanics of human VF motion remains limited.

AIM

Optical coherence tomography (OCT) is a micrometer-resolution, high-speed endoscopic imaging modality which acquires cross-sectional images of tissue. Our study aimed to leverage OCT technology and develop quantitative methods for analyzing the anatomy and kinematics of in vivo VF motion in the coronal plane.

APPROACH

A custom handheld laryngeal stage was used to capture OCT images with 800 A-lines at 250 Hz. Automated image postprocessing and analytical methods were developed.

RESULTS

Novel kinematic analysis of in vivo, long-range OCT imaging of the vibrating VF in awake human subjects is reported. Cross-sectional, coronal-plane panoramic videos of the larynx during phonation are presented with three-dimensional videokymographic and space-time velocity analysis of VF motion.

CONCLUSIONS

Long-range OCT with automated computational methods allows for cross-sectional dynamic laryngeal imaging and has the potential to broaden our understanding of human VF biomechanics and sound production.

Kymographic characteristics of voice in women with Polycystic ovary syndrome

PURPOSE

Polycystic ovary syndrome (PCOS) is heterogenous condition with commonly associated symptoms include irregular menstrual cycle, hirsutism, baldness, adult acne, and weight gain There have been few attempts at profiling the voice characteristics of women with polycystic ovary syndrome. Videokymography enables to detect even subtle variationsin vocal fold vibrations. The aim of the present study was to study the videokymographic characteristics among women with PCOS.

METHODS

A cross-sectional study was carried out among 50 women with and without PCOS diagnosed on ultrasonography. Videokymography was carried out and the characteristics were perceptually analyzed using a vocal fold kymographic rating scale. The analysis of the kymogram was done for the following characteristics; presence of vocal fold vibration,interference of surroundings, Cycle to cycle variability, left-right asymmetry,cycle aberrations and shape of lateral peaks. The kymographic images were obtained for all the participants of both the groups and a subjective consensus evaluation was done by two clinicians. The percentage of participants with the listed kymographic characteristics were tabulated. Chi Square test was also done to decide if there was a significant difference between the two groups for different kymographic features of vocal fold vibration.

RESULTS

Six of the 25 women with PCOS were found to have abnormal kymographic features such as surrounding structural interference, presence of cycle to cycle variability and the shape of lateral peaks.

CONCLUSION

Early detection of the vocal abnormalities in individuals with PCOS would help in the vocal rehabilitation especially for professional voice users.

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.

Immediate and partial neural dysfunction after thyroid and parathyroid surgery: Need for recognition, laryngeal exam, and early treatment

BACKGROUND

Laryngeal dysfunction after thyroid and parathyroid surgery requires early recognition and a standardized approach for patients that present with voice, swallowing, and breathing issues. The Endocrine Committee of the American Head and Neck Society (AHNS) convened a panel to define the terms "immediate vocal fold paralysis" and "partial neural dysfunction" and to provide clinical consensus statements based on review of the literature, integrated with expert opinion of the group.

METHODS

A multidisciplinary expert panel constructed the manuscript and recommendations for laryngeal dysfunction after thyroid and parathyroid surgery. A meta-analysis was performed using the literature and published guidelines. Consensus was achieved using polling and a modified Delphi approach.

RESULTS

Twenty-two panelists achieved consensus on five statements regarding the role of early identification and standardization of evaluation for patients with "immediate vocal fold paralysis" and "partial neural dysfunction" after thyroid and parathyroid surgery.

CONCLUSION

After endorsement by the AHNS Endocrine Section and Quality of Care Committee, it received final approval from the AHNS Council.

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.

Comparison of Pitch Strength With Perceptual and Other Acoustic Metric Outcome Measures Following Medialization Laryngoplasty

INTRODUCTION

The diagnoses of voice disorders, as well as treatment outcomes, are often tracked using visual (eg, stroboscopic images), auditory (eg, perceptual ratings), objective (eg, from acoustic or aerodynamic signals), and patient report (eg, Voice Handicap Index and Voice-Related Quality of Life) measures. However, many of these measures are known to have low to moderate sensitivity and specificity for detecting changes in vocal characteristics, including vocal quality.

OBJECTIVE

The objective of this study was to compare changes in estimated pitch strength (PS) with other conventionally used acoustic measures based on the cepstral peak prominence (smoothed cepstral peak prominence, cepstral spectral index of dysphonia, and acoustic voice quality index), and clinical judgments of voice quality (GRBAS [grade, roughness, breathiness, asthenia, strain] scale) following laryngeal framework surgery.

METHODS

This study involved post hoc analysis of recordings from 22 patients pretreatment and post treatment (thyroplasty and behavioral therapy). Sustained vowels and connected speech were analyzed using objective measures (PS, smoothed cepstral peak prominence, cepstral spectral index of dysphonia, and acoustic voice quality index), and these results were compared with mean auditory-perceptual ratings by expert clinicians using the GRBAS scale.

RESULTS

All four acoustic measures changed significantly in the direction that usually indicates improved voice quality following treatment (P < 0.005). Grade and breathiness correlated the strongest with the acoustic measures (|r| ~ 0.7) with strain being the least correlated.

CONCLUSIONS

Acoustic analysis on running speech highly correlates with judged ratings. PS is a robust, easily obtained acoustic measure of voice quality that could be useful in the clinical environment to follow treatment of voice disorders.

Analysis Method for Laryngeal High-Speed Videoendoscopy: Development of the Criteria for the Measurement Input

Despite its clear advantages, laryngeal high-speed videoendoscopy (LHSV) has not yet been accepted as a routine imaging tool for the evaluation of vocal fold vibration due to the unavailability of methods to effectively analyze the huge number of images from the LHSV recording. Recently, a promising LHSV-based analysis method has been introduced. The ability of this analysis method in studying the vocal fold vibratory behaviors had been substantially demonstrated. However, some practical aspects of its clinical applications still require further attention. Most fundamental is that the criteria for the measurement input ie, a segment of interest (SOI), which has not been fully defined. Particularly, the length of the SOI and the location along the sample, where it needs to be selected require further confirmation. Meanwhile, the analysis using any options of a well-delineated glottal area demands verification. Without clear criteria for the SOI, it is difficult to demonstrate the relevance of this analysis method in clinical voice assessment. Therefore, the aim of the present study is to establish the criteria for the SOI, which involved the investigations on the length of the SOI and the location along the sample, where it needs to be selected, as well as the use of any options of a well-delineated glottal area for analysis. The participants in the present study consisted of 36 young normophonic females. The methods involved LHSV recording of the images of the vibrating vocal folds. The captured images were then analyzed using the method. The LHSV-based measures from the analyses were compared according to the specified procedures of each investigation. Results indicated that 2000 frames should be used as the SOI length. The SOI could be selected at any location along the sample as long as well-delineated glottal areas were observed. With the current findings, a more conclusive measurement protocol is available to ensure reliable LHSV-based measures. The findings further support this analysis method for clinical application, which in turn promote LHSV as a reliable laryngeal imaging tool in clinical setting.

[Combined application of modern endoscopic techniques in the detection of precancerous and malignant lesions of larynx]

INTRODUCTION

Early detection of malignant laryngeal tumors is crucial but still challenging. And 5-year survival rate depends on a stage of revealing. The aim of the study - assessment of the effectiveness of combined application of narrow band imaging and contact endoscopy in visualization of neoangiogenesis.

MATERIAL AND METHODS

102 patients were included in this study. All the patients were evaluated by means of narrow band imaging and contact endoscopy.

RESULTS

Combined application of narrow band imaging and contact endoscopy gained a high level of effectiveness: accuracy - 93.9%, sensitivity - 96%, specificity - 93.4%, positive predictive value - 94.3%, negative predictive value - 93.4%.

CONCLUSION

Combined application of narrow band imaging and contact endoscopy may contribute to early detection of malignant laryngeal tumors.

Synchronized, concurrent optical coherence tomography and videostroboscopy for monitoring vocal fold morphology and kinematics

Voice disorders affect a large number of adults in the United States, and their clinical evaluation heavily relies on laryngeal videostroboscopy, which captures the medial-lateral and anterior-posterior motion of the vocal folds using stroboscopic sampling. However, videostroboscopy does not provide direct visualization of the superior-inferior movement of the vocal folds, which yields important clinical insight. In this paper, we present a novel technology that complements videostroboscopic findings by adding the ability to image the coronal plane and visualize the superior-inferior movement of the vocal folds. The technology is based on optical coherence tomography, which is combined with videostroboscopy within the same endoscopic probe to provide spatially and temporally co-registered images of the mucosal wave motion, as well as vocal folds subsurface morphology. We demonstrate the capability of the rigid endoscopic probe, in a benchtop setting, to characterize the complex movement and subsurface structure of the aerodynamically driven excised larynx models within the 50 to 200 Hz phonation range. Our preliminary results encourage future development of this technology with the goal of its use for in vivo laryngeal imaging.

Influence of vocal fold cover layer thickness on its vibratory dynamics during voice production

The influence of vocal fold cover layer thickness on the flow-induced vibration and voice production was studied by using a continuum-mechanics based computational model. The cover-body thickness ratio of a three-layer vocal fold was systematically varied. The effect on the vocal fold stiffness, eigenfrequencies and eigenmodes, fundamental frequencies, glottal flow rate, vocal fold vibratory dynamics, and synchronization of the eigenmodes were analyzed by using the structure eigen analysis and flow-structure interaction simulations. It was found that the cover-body layer thickness ratio significantly affected the strength and synchronization of the eigenmodes during flow-structure interactions, and ultimately affected the fundamental frequency and vibration pattern. With the increasing cover-body thickness ratio, the strength of the wave-type higher-eigenfrequency modes increased, and that resulted in a nonlinear bifurcation of the system in which the system evolved from a regular periodic vibration to a periodic doubling vibration and then back to a regular periodic vibration with increased fundamental frequencies. During the transition, the system vibrated chaotically. Because of the increased strength of the wave-type modes, the maximum divergent angle of the glottis was also increased with the increasing cover-body thickness ratio.

Impact of Subharmonic and Aperiodic Laryngeal Dynamics on the Phonatory Process Analyzed in Ex Vivo Rabbit Models

Normal voice is characterized by periodic oscillations of the vocal folds. On the other hand, disordered voice dynamics (e.g., subharmonic and aperiodic oscillations) are often associated with voice pathologies and dysphonia. Unfortunately, not all investigations may be conducted on human subjects; hence animal laryngeal studies have been performed for many years to better understand human phonation. The rabbit larynx has been shown to be a potential model of the human larynx. Despite this fact, only a few studies regarding the phonatory parameters of rabbit larynges have been performed. Further, to the best of our knowledge, no ex vivo study has systematically investigated phonatory parameters from high-speed, audio and subglottal pressure data with irregular oscillations. To remedy this, the present study analyzes experiments with sustained phonation in 11 ex vivo rabbit larynges for 51 conditions of disordered vocal fold dynamics. (1) The results of this study support previous findings on non-disordered data, that the stronger the glottal closure insufficiency is during phonation, the worse the phonatory characteristics are; (2) aperiodic oscillations showed worse phonatory results than subharmonic oscillations; (3) in the presence of both types of irregular vibrations, the voice quality (i.e., cepstral peak prominence) of the audio and subglottal signal greatly deteriorated compared to normal/periodic vibrations. In summary, our results suggest that the presence of both types of irregular vibration have a major impact on voice quality and should be considered along with glottal closure measures in medical diagnosis and treatment.

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

OBJECTIVES

A major limitation of comparing the efficacy of videostroboscopy (VS) and high-speed videoendoscopy (HSV) is the lack of an objective reference by which to compare the functional assessment ratings of the two techniques. For patients with vocal fold mass lesions, intraoperative measures of lesion size and depth may serve as this objective reference. This study compared the relationships between the pre- to postoperative change in VS and HSV visual-perceptual ratings to intraoperative measures of lesion size and depth.

DESIGN

Prospective visual-perceptual study with intraoperative measures of lesion size and depth.

METHODS

VS and HSV samples were obtained preoperatively and postoperatively from 28 patients with vocal fold lesions and from 17 vocally healthy controls. Two experienced clinicians rated amplitude, mucosal wave, vertical phase difference, left-right phase asymmetry, and vocal fold edge on a visual-analog scale using both imaging techniques. The change in perioperative ratings from VS and HSV was compared between groups and correlated to intraoperative measures of lesion size and depth.

RESULTS

HSV was as reliable as VS for ratings of amplitude and edge, and substantially more reliable for ratings of mucosal wave and left-right phase asymmetry. Both VS and HSV had mild-moderate correlations between change in perioperative ratings and intraoperative measures of lesion area. Change in function could be obtained in more patients and for more parameters using HSV than VS. Group differences were noted for postoperative ratings of amplitude and edge; however, these differences were within one level of the visual-perceptual rating scale. The presence of asynchronicity in VS recordings renders vibratory features either uninterpretable or potentially distorted and thus should not be rated.

CONCLUSIONS

Amplitude and edge are robust vibratory measures for perioperative functional assessment, regardless of imaging modality. HSV is indicated for evaluation of subepithelial lesions or if asynchronicity is present in the VS image sequence.

Visual and Automatic Evaluation of Vocal Fold Mucosal Waves Through Sharpness of Lateral Peaks in High-Speed Videokymographic Images

INTRODUCTION

The sharpness of lateral peaks is a visually helpful clinical feature in high-speed videokymographic (VKG) images indicating vertical phase differences and mucosal waves on the vibrating vocal folds and giving insights into the health and pliability of vocal fold mucosa. This study aims at investigating parameters that can be helpful in objectively quantifying the lateral peak sharpness from the VKG images.

METHOD

Forty-five clinical VKG images with different degrees of sharpness of lateral peaks were independently evaluated visually by three raters. The ratings were compared to parameters obtained by automatic image analysis of the vocal fold contours: Open Time Percentage Quotients (OTQ) and Plateau Quotients (PQ). The OTQ parameters were derived as fractions of the period during which the vocal fold displacement exceeds a predetermined percentage of the vibratory amplitude. The PQ parameters were derived similarly but as a fraction of the open phase instead of a period.

RESULTS

The best correspondence between the visual ratings and the automatically derived quotients were found for the OTQ and PQ parameters derived at 95% and 80% of the amplitude, named OTQ₉₅, PQ₉₅, OTQ₈₀ and PQ₈₀. Their Spearman's rank correlation coefficients were in the range of 0.73 to 0.77 (P < 0.001) indicating strong relationships with the visual ratings. The strengths of these correlations were similar to those found from inter-rater comparisons of visual evaluations of peak sharpness.

CONCLUSION

The Open time percentage and Plateau quotients at 95% and 80% of the amplitude stood out as the possible candidates for capturing the sharpness of the lateral peaks with their reliability comparable to that of visual ratings.

Cross-cultural Adaptation and Validation of the Greek Voice Handicap Index-10 (GVHI-10) With Additional Receiver Operating Characteristic Analysis

OBJECTIVE(S)

The use of subjective evaluation tools are proven useful and of high clinical value in the case of voice disordered population. For that type of evaluation, self-assessment questionnaires about the severity of the voice like Voice Handicap Index-30 (VHI-30) have been developed. The VHI-30 is the most studied tool which includes psychometrically robustness while guiding physician's therapeutic decision making. Additionally, a valid abbreviated version of VHI-30 was developed for the first time in the Greek Language which is named as Greek Voice Handicap Index-10 (GVHI-10). Consequently, the aim of our study was to validate the proposed version of the VHI-10.

METHODS

Ninety nondysphonic individuals and 90 dysphonic patients were classified by Otolaryngologists and Speech Language Pathologists. The study's subjects were evaluated with endoscopy and stroboscopy. Also, they were administrated the GVHI-30 and the translated version of the Voice Evaluation Template (VEF). The GVHI-10 was extracted by the Greek version of VHI-30.

RESULTS

The group with voice disorders exhibited higher statistical significance in all GVHI-10 scores compared to those of the control group. The GVHI-10 showed a high internal consistency (Cronbach's a = 0.915 and split-half reliability coefficient equal to 0.86), good sensitivity compared to Greek VHI-30 (r = 0.764, P = 0.000) and intraclass correlation. A total cut-off point equal to 6.50 (AUC: 0.964; P < 0.001) was also calculated.

CONCLUSIONS

The proposed version of GVHI-10 distinguished the perceived levels of voice between dysphonic and nondysphonic groups and between different voice disordered populations. The GVHI-10 is shown to be clinically valid and sensitive exhibiting high reliability.

Quantitative Measurement of the Three-dimensional Structure of the Vocal Folds and Its Application in Identifying the Type of Cricoarytenoid Joint Dislocation

OBJECTIVE

The objective of this study was to quantitatively measure the three-dimensional (3D) structure of the vocal folds in normal subjects and in patients with different types of cricoarytenoid dislocation. We will analyze differences in parameters between the groups and also determine if any morphologic parameters possess utility in distinguishing the type and the degree of cricoarytenoid dislocation.

STUDY DESIGN

This retrospective study was conducted using university hospital data.

METHODS

Subjects' larynges were scanned using dual-source computed tomography (CT). The normal subjects were divided into deep-inhalation and phonation groups, and patients with cricoarytenoid joint dislocation were divided into anterior-dislocation and posterior-dislocation groups. Membranous vocal fold length and width were measured directly on the thin-section CT images. Vocal fold and airway 3D models were constructed using Mimics software and used in combination to measure vocal fold thickness, subglottal convergence angle, and oblique angle of the vocal folds.

RESULTS

The phonation group displayed a greater vocal fold width, greater oblique angle, thinner vocal folds, and a smaller subglottal convergence angle than those of the deep-inhalation group (P < 0.05). The anterior-dislocation group displayed a smaller oblique angle and subglottal convergence angle than the posterior-dislocation group (P < 0.05).

CONCLUSIONS

The 3D structure of the vocal folds during deep inhalation and phonation can be accurately measured using dual-source CT and laryngeal 3D reconstruction. As the anterior-dislocation group yielded negative values for the oblique angle and the posterior-dislocation group yielded positive values, the oblique angle of the vocal folds may possess utility for distinguishing the type and for quantitatively determining the degree of cricoarytenoid dislocation.

Videokymographic Visualization of Phonasthenia: A Nonorganic Voice Disorder

BACKGROUND

Phonasthenia is a voice disorder where the larynx looks essentially normal and dysphonia is not heard but felt by the patient. This study aims to use videokymography (VKG) to detect any abnormalities in the vibratory pattern in phonasthenia and to find out whether or not these abnormalities change after vocal loading.

METHODS

Thirty-seven phonasthenic patients and 31 normal subjects participated in a detailed protocol, including analysis of subjective complaints and videokymographic quasi-objective parameters (baseline) followed by loading their voices through prolonged loud reading for 45 min. A second evaluation (experimental) was done after loading.

RESULTS

Before vocal loading, patients had significantly more symptoms in all questionnaire questions and higher maximum width difference in VKG than controls. When pre- and postloading values were compared, both groups experienced more symptoms after loading (significant in most of the questions), while the pre- and post-VKG parameters did not show significant differences neither in patients nor controls. On comparing their percent change, the only statistically significant difference between the 2 groups was a greater change in the total score of the questionnaire in the control group.

CONCLUSION

Patients had more vocal fatigue symptoms and more amplitude asymmetry between left and right vocal folds than normal subjects.

Arytenoid cartilage movements are hypokinetic in Parkinson's disease: A quantitative dynamic computerised tomographic study

BACKGROUND

Voice change is one of the earliest features of Parkinson's disease. However, quantitative studies of vocal fold dynamics which are needed to provide insight into disease biology, aid diagnosis, or track progression, are few.

METHODS

We therefore quantified arytenoid cartilage movements and glottic area during repeated phonation in 15 patients with Parkinson's disease (symptom duration < 6 years) and 19 controls, with 320-slice computerised tomography (CT). We related these measures to perceptual voice evaluations and spirometry. We hypothesised that Parkinson's disease patients have a smaller inter-arytenoid distance, a preserved or larger glottic area because vocal cord bowing has previously been reported, less variability in loudness, more voice dysdiadochokinesis and breathiness and a shortened phonation time because of arytenoid hypokinesis relative to glottic area.

RESULTS

Inter-arytenoid distance in Parkinson's disease patients was moderately smaller (Mdn = 0.106, IQR = 0.091-0.116) than in controls (Mdn = 0.132, IQR = 0.116-0.166) (W = 212, P = 0.015, r = -0.42), normalised for anatomical and other inter-subject variance, analysed with two-tailed Wilcoxon's rank sum test. This finding was confirmed in a linear mixed model analysis-Parkinson's disease significantly predicted a reduction in the dependent variable, inter-arytenoid distance (b = -0.87, SEb = 0.39, 95% CI [-1.66, -0.08], t(31) = -2.24, P = 0.032). There was no difference in glottic area. On perceptual voice evaluation, patients had more breathiness and dysdiadochokinesis, a shorter maximum phonation time, and less variability in loudness than controls. There was no difference in spirometry after adjustment for smoking history.

CONCLUSIONS

As predicted, vocal fold adduction movements are reduced in Parkinson's disease on repeated phonation but glottic area is maintained. Some perceptual characteristics of Parkinsonian speech reflect these changes. We are the first to use 320-slice CT to study laryngeal motion. Our findings indicate how Parkinson's disease affects intrinsic laryngeal muscle position and excursion.

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.

Laryngeal High-Speed Videoendoscopy: Sensitivity of Objective Parameters towards Recording Frame Rate

The current use of laryngeal high-speed videoendoscopy in clinic settings involves subjective visual assessment of vocal fold vibratory characteristics. However, objective quantification of vocal fold vibrations for evidence-based diagnosis and therapy is desired, and objective parameters assessing laryngeal dynamics have therefore been suggested. This study investigated the sensitivity of the objective parameters and their dependence on recording frame rate. A total of 300 endoscopic high-speed videos with recording frame rates between 1000 and 15 000 fps were analyzed for a vocally healthy female subject during sustained phonation. Twenty parameters, representing laryngeal dynamics, were computed. Four different parameter characteristics were found: parameters showing no change with increasing frame rate; parameters changing up to a certain frame rate, but then remaining constant; parameters remaining constant within a particular range of recording frame rates; and parameters changing with nearly every frame rate. The results suggest that (1) parameter values are influenced by recording frame rates and different parameters have varying sensitivities to recording frame rate; (2) normative values should be determined based on recording frame rates; and (3) the typically used recording frame rate of 4000 fps seems to be too low to distinguish accurately certain characteristics of the human phonation process in detail.

The influence of water resistance therapy on vocal fold vibration: a high-speed digital imaging study

PURPOSE

This study investigated the influence of tube phonation into water on vocal fold vibration.

METHOD

Eight participants were analyzed via high-speed digital imaging while phonating into a silicon tube with the free end submerged into water. Two test sequences were studied: (1) phonation pre, during, and post tube submerged 5 cm into water; and (2) phonation into tube submerged 5 cm, 10 cm, and 18 cm into water. Several glottal area parameters were calculated using phonovibrograms.

RESULTS

The results showed individual differences. However, certain trends were possible to identify based on similar results found for the majority of participants. Amplitude-to-length ratio, harmonic-to-noise ratio, and spectral flatness (derived from glottal area) decreased for all tube immersion depths, while glottal closing quotient increased for 10 cm immersion and contact quotient for 18 cm immersion. Closed quotient decreased during phonation into the tube at 5 cm depth, and jitter decreased during and after it.

CONCLUSION

Results suggest that the depth of tube submersion appears to have an effect on phonation. Shallow immersion seems to promote smoother and more stable phonation, while deeper immersion may involve increased respiratory and glottal effort to compensate for the increased supraglottal resistance. This disparity, which is dependent upon the degree of flow resistance, should be considered when choosing treatment exercises for patients with various diagnoses, namely hyperfunctional or hypofunctional dysphonia.

Extension and Application of High-Speed Digital Imaging Analysis Via Spatiotemporal Correlation and Eigenmode Analysis of Vocal Fold Vibration Before and After Polyp Excision

OBJECTIVES/HYPOTHESIS

To evaluate the spatiotemporal correlation of vocal fold vibration using eigenmode analysis before and after polyp removal and explore the potential clinical relevance of spatiotemporal analysis of correlation length and entropy as quantitative voice parameters. We hypothesized that increased order in the vibrating signal after surgical intervention would decrease the eigenmode-based entropy and increase correlation length.

STUDY DESIGN

Prospective case series.

METHODS

Forty subjects (23 males, 17 females) with unilateral (n = 24) or bilateral (n = 16) polyps underwent polyp removal. High-speed videoendoscopy was performed preoperatively and 2 weeks postoperatively. Spatiotemporal analysis was performed to determine entropy, quantification of signal disorder, correlation length, size, and spatially ordered structure of vocal fold vibration in comparison to full spatial consistency. The signal analyzed consists of the vibratory pattern in space and time derived from the high-speed video glottal area contour.

RESULTS

Entropy decreased (Z = -3.871, P < .001) and correlation length increased (t = -8.913, P < .001) following polyp excision. The intraclass correlation coefficients (ICC) for correlation length and entropy were 0.84 and 0.93.

CONCLUSION

Correlation length and entropy are sensitive to mass lesions. These parameters could potentially be used to augment subjective visualization after polyp excision when evaluating procedural efficacy.

The Potential Role of Subglottal Convergence Angle and Measurement

OBJECTIVE

This study aimed to explore subglottal convergence angle measurement. We hypothesize that the angle will change with glottis closure condition. Changes to the angle may alter vocal fold stress distribution, which could result in vocal fold pathologies.

METHODS

Three vocal fold positions were evaluated by the degree of glottal closure and divided into three groups. Neck computed tomographic images of the subjects were gathered, and three-dimensional (3D) models of the vocal folds and the airway were reconstructed using Mimics software, through which the subglottal convergence angle was measured. Using one-way factor analysis of variance, we compared the angle among three groups. We explored the effect of the angle on vibration based on the material oblique section stress analysis.

RESULTS

The subglottal convergence angle was effectively measured from 3D models. The angle changed with degree of glottal closure, with statistically significant differences among the three groups (P < 0.01). Changes to the angle alter subglottal stress distribution in the subglottal shear or normal direction by the material oblique section stress analysis theory. Larger subglottal convergence angle might reduce subglottal pressure in the shear direction below the vocal folds, which would make vibration and vocal fold mucosal wave generation more difficult.

CONCLUSION

3D model generation from computed tomographic data is an effective method of measuring the subglottal convergence angle, which changes with the degree of glottis closure, and may affect subglottal pressure distribution in the subglottal shear or normal direction and influence vocal fold vibration.

Dynamic vocal fold parameters with changing adduction in ex-vivo hemilarynx experiments

Ex-vivo hemilarynx experiments allow the visualization and quantification of three-dimensional dynamics of the medial vocal fold surface. For three excised human male larynges, the vibrational output, the glottal flow resistance, and the sound pressure during sustained phonation were analyzed as a function of vocal fold adduction for varying subglottal pressure. Empirical eigenfunctions, displacements, and velocities were investigated along the vocal fold surface. For two larynges, an increase of adduction level resulted in an increase of the glottal flow resistance at equal subglottal pressures. This caused an increase of lateral and vertical oscillation amplitudes and velocity indicating an improved energy transfer from the airflow to the vocal folds. In contrast, the third larynx exhibited an amplitude decrease for rising adduction accompanying reduction of the flow resistance. By evaluating the empirical eigenfunctions, this reduced flow resistance was assigned to an unbalanced oscillation pattern with predominantly lateral amplitudes. The results suggest that adduction facilitates the phonatory process by increasing the glottal flow resistance and enhancing the vibrational amplitudes. However, this interrelation only holds for a maintained balanced ratio between vertical and lateral displacements. Indeed, a balanced vertical-lateral oscillation pattern may be more beneficial to phonation than strong periodicity with predominantly lateral vibrations.

Laryngeal examination in thyroid and parathyroid surgery: An American Head and Neck Society consensus statement: AHNS Consensus Statement

This American Head and Neck Society (AHNS) consensus statement discusses the techniques of laryngeal examination for patients undergoing thyroidectomy and parathyroidectomy. It is intended to help guide all clinicians who diagnose or manage adult patients with thyroid disease for whom surgery is indicated, contemplated, or has been performed. This consensus statement concludes that flexible transnasal laryngoscopy is the optimal laryngeal examination technique, with other techniques including laryngeal ultrasound and stroboscopy being useful in selected scenarios. © 2016 Wiley Periodicals, Inc. Head Neck 38: 811-819, 2016.

Parameters of the assessment of voice quality and clinical manifestation of rheumatoid arthritis

PURPOSE

The aim of the study was to investigate the voice quality parameters in 72 rheumatoid arthritis (RA) patients and their relationships with the clinical manifestations and disease activity. The control group consisted of 30 healthy subjects.

MATERIAL AND METHODS

All RA patients were evaluated by extensive clinical, laboratory and radiographic studies. The phoniatric assessment included the analysis of vocal folds vibrations by digital stroboscopy (DS) of the larynx using HRES ENDOCAM 5562 system, digital kymography (DKG) and High-Speed Digital Imaging (HSDI) technique. The acoustic voice analysis was conducted using DiagnoScope Specialist program.

RESULTS

Voice quality disorders were registered in 32 (44.44%) RA patients and observed more frequently in patients with moderate and severe activity (DAS28≥3.2) than in mild RA. In digital stroboscopy, confirmed by digital kymography, the hypofunctional dysphonia was observed especially in patients with DAS28≥3.2. Outcomes of the subjective assessment of voice quality were in accordance with the objective parameters and acoustic voice examination.

CONCLUSIONS

In RA patients the most frequent voice quality disorders with hypofunctional dysphonia were registered. The relationships between voice quality disorders, clinical activity and radiographic progression of RA patients were observed. Digital stroboscopy, digital kymography, High-Speed Digital Imaging and acoustic voice analysis used in the complex diagnosis of RA confirmed the presence of pathological changes in the larynx. There is a need of cooperation between rheumatologists and phoniatricians in the diagnosis and treatment of dysphonia in RA patients.

4K Video-Laryngoscopy and Video-Stroboscopy: Preliminary Findings

INTRODUCTION

4K video is a new format. At 3840 × 2160 resolution, it has 4 times the resolution of standard 1080 high definition (HD) video. Magnification can be done without loss of resolution. This study uses 4K video for video-stroboscopy.

MATERIAL AND METHOD

Forty-six patients were examined by conventional video-stroboscopy (digital 3 chip CCD) and compared with 4K video-stroboscopy. The video was recorded on a Blackmagic 4K cinema production camera in CinemaDNG RAW format. The video was played back on a 4K monitor and compared to standard video. Pathological conditions included: polyps, scar, cysts, cancer, sulcus, and nodules.

RESULTS

Successful 4K video recordings were achieved in all subjects using a 70° rigid endoscope. The camera system is bulky. The examination is performed similarly to standard video-stroboscopy. Playback requires a 4K monitor. As expected, the images were far clearer in detail than standard video. Stroboscopy video using the 4K camera was consistently able to show more detail. Two patients had diagnosis change after 4K viewing.

CONCLUSION

4K video is an exciting new technology that can be applied to laryngoscopy. It allows for cinematic 4K quality recordings. Both continuous and stroboscopic light can be used for visualization. Its clinical utility is feasible, but usefulness must be proven.