Quantifying Protein Dynamics by Kymograph Analysis.

Time-lapse imaging of the subcellular localization and dynamic behavior of proteins is critical to understand their biological functions in cells. With the advent of various methodologies and computational tools, the precise tracking and quantification of protein spatiotemporal dynamics have become feasible. Kymograph analysis, in particular, has been extensively adopted for the quantitative assessment of proteins, vesicles, and organelle movements. However, conventional kymograph analysis, which is based on a single linear trajectory, may not comprehensively capture the complexity of proteins that alter their course during intracellular transport and activity. In this chapter, we introduced an advanced protocol for whole-cell kymograph analysis that allows for three-dimensional (3D) tracking of protein dynamics. This method was validated through the analysis of tip-focused endocytosis and exocytosis processes in growing tobacco pollen tubes by employing both the advanced whole-cell and classical kymograph methods. In addition, we enhanced this method by integrating pseudo-colored kymographs that enables the direct visualization of changes in protein fluorescence intensity with fluorescence recovery after photobleaching to advance our understanding of protein localization and dynamics. This comprehensive method offers a novel insight into the intricate dynamics of protein activity within the cellular context.

A Hands-on Guide to AmoePy - a Python-Based Software Package to Analyze Cell Migration Data.

Amoeboid cell motility is fundamental for a multitude of biological processes such as embryogenesis, immune responses, wound healing, and cancer metastasis. It is characterized by specific cell shape changes: the extension and retraction of membrane protrusions, known as pseudopodia. A common approach to investigate the mechanisms underlying this type of cell motility is to study phenotypic differences in the locomotion of mutant cell lines. To characterize such differences, methods are required to quantify the contour dynamics of migrating cells. AmoePy is a Python-based software package that provides tools for cell segmentation, contour detection as well as analyzing and simulating contour dynamics. First, a digital representation of the cell contour as a chain of nodes is extracted from each frame of a time-lapse microscopy recording of a moving cell. Then, the dynamics of these nodes-referred to as virtual markers-are tracked as the cell contour evolves over time. From these data, various quantities can be calculated that characterize the contour dynamics, such as the displacement of the virtual markers or the local stretching rate of the marker chain. Their dynamics is typically visualized in space-time plots, the so-called kymographs, where the temporal evolution is displayed for the different locations along the cell contour. Using AmoePy, you can straightforwardly create kymograph plots and videos from stacks of experimental bright-field or fluorescent images of motile cells. A hands-on guide on how to install and use AmoePy is provided in this chapter.

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.

Evaluation of Voice and Vocal Fold Vibration after Thyroidectomy Using Two-Dimensional Scanning Digital Kymography and High-Speed Videolaryngoscopy.

OBJECTIVE: Vocal dysfunction is one of the major factors that affect the health-related quality of life of patients after thyroidectomy. Conventionally, voice changes after thyroidectomy have been evaluated by videostroboscopy and acoustic analysis. Recently, two-dimensional scanning digital kymography (2D DKG) and high-speed videolaryngoscopy (HSV) have been developed and have shown usefulness in accurately evaluating vocal fold vibration. This study aimed to evaluate changes of vocal fold vibration and voice after thyroidectomy using 2D DKG and HSV. MATERIALS AND METHODS: We evaluated the voice and vocal fold movement of 24 female patients who underwent thyroidectomy in a single tertiary hospital from December 2018 to October 2019. We obtained serial 2D DKG and HSV data one day before thyroidectomy, and 1 week and 1 month after surgery. We analyzed the peak glottal area of HSV, amplitude symmetry index, phase symmetry index, and open quotient using the 2D DKG data. The parameters were calculated at three levels of the vocal fold (line 1=anterior, line 2=middle, line 3=posterior). In the same period, we performed a voice analysis evaluating voice frequency, jitter, shimmer, and noise to harmonic ratio. We also assessed maximum phonation time and subjective voice changes with voice handicap index-10 questionnaires. RESULTS: Highest frequency (F-high), frequency range (F-range), and fundamental frequency (F0) decreased at 1 week and 1 month after thyroidectomy compared with preoperative values (P = 0.003, 0.004, <0.001 and P = 0.002, 0.015, 0.001 at 1 week and 1 month, respectively). The open quotient of 2D DKG in lines 1 and 2 increased at 1 week after thyroidectomy (P = 0.011, 0.006) and recovered to preoperative levels at 1 month postoperatively (P = 0.189, 0.153). Other quantitative measures by 2D DKG and HSV did not show significant changes between the preoperative and postoperative periods. In a correlation analysis between vocal parameters from the acoustic analysis and the values obtained from 2D DKG and HSV, significant negative correlations were observed between peak glottal area and three factors (F-high, F-range, and F0) at 1 month after surgery (r = -0.589, -0.529, -0.708; P = 0.002, 0.008, <0.001, respectively). There were positive correlations between phase symmetry indexes in lines 1 and 2 and shimmer at 1 week after thyroidectomy (r = 0.489, 0.425; P = 0.015, 0.038, respectively). Phase symmetry index in line 3 showed a significant negative correlation with maximum phonation time at both 1 week and 1 month after surgery (r = -0.497, -0.439; P = 0.013, 0.032, respectively). However, there was no correlation between total score on the voice handicap index-10 questionnaires and quantitative measurements of vocal fold vibration. CONCLUSION: 2D DKG and HSV may provide important information on vocal fold vibratory patterns after thyroidectomy, and measurements made with them were correlated with maximal phonation time and acoustic parameters such as F-high, F-range, F0, shimmer.

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.

A Portable Smartphone-Based Laryngoscope System for High-Speed Vocal Cord Imaging of Patients With Throat Disorders: Instrument Validation Study.

BACKGROUND: Currently, high-speed digital imaging (HSDI), especially endoscopic HSDI, is routinely used for the diagnosis of vocal cord disorders. However, endoscopic HSDI devices are usually large and costly, which limits access to patients in underdeveloped countries and in regions with inadequate medical infrastructure. Modern smartphones have sufficient functionality to process the complex calculations that are required for processing high-resolution images and videos with a high frame rate. Recently, several attempts have been made to integrate medical endoscopes with smartphones to make them more accessible to people in underdeveloped countries. OBJECTIVE: This study aims to develop a smartphone adaptor for endoscopes, which enables smartphone-based vocal cord imaging, to demonstrate the feasibility of performing high-speed vocal cord imaging via the high-speed imaging functions of a high-performance smartphone camera, and to determine the acceptability of the smartphone-based high-speed vocal cord imaging system for clinical applications in developing countries. METHODS: A customized smartphone adaptor optical relay was designed for clinical endoscopy using selective laser melting-based 3D printing. A standard laryngoscope was attached to the smartphone adaptor to acquire high-speed vocal cord endoscopic images. Only existing basic functions of the smartphone camera were used for HSDI of the vocal cords. Extracted still frames were observed for qualitative glottal volume and shape. For image processing, segmented glottal and vocal cord areas were calculated from whole HSDI frames to characterize the amplitude of the vibrations on each side of the glottis, including the frequency, edge length, glottal areas, base cord, and lateral phase differences over the acquisition time. The device was incorporated into a preclinical videokymography diagnosis routine to compare functionality. RESULTS: Smartphone-based HSDI with the smartphone-endoscope adaptor could achieve 940 frames per second and a resolution of 1280 by 720 frames, which corresponds to the detection of 3 to 8 frames per vocal cycle at double the spatial resolution of existing devices. The device was used to image the vocal cords of 4 volunteers: 1 healthy individual and 3 patients with vocal cord paralysis, chronic laryngitis, or vocal cord polyps. The resultant image stacks were sufficient for most diagnostic purposes. The cost of the device including the smartphone was lower than that of existing HSDI devices. The image processing and analytics demonstrated the successful calculation of relevant diagnostic variables from the acquired images. Patients with vocal pathologies were easily differentiable in the quantitative data. CONCLUSIONS: A smartphone-based HSDI endoscope system can function as a point-of-care clinical diagnostic device. The resulting analysis is of higher quality than that accessible by videostroboscopy and promises comparable quality and greater accessibility than HSDI. In particular, this system is suitable for use as an accessible diagnostic tool in underdeveloped areas with inadequate medical service infrastructure.

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.

[Application of videostrobokymography in analyzing factors affecting voice after surgery].

Objective:To elucidate the value of videostrobokymography in the evaluation of the characteristics of vocal cord vibration after the surgery. Methods:To analyze the spectrum of the voice before and after the microsurgery of the vocal folds. Using the videostrobokymography to reveal the changes of vibration, especially in the cases with poor spectrum elevation but without obvious recurrence. Results:Two patients were with elevated vocal parameters; 2 patients were with partially elevated vocal parameters（one with Jitter decreased while others elevated; one with Shimmer decreased while others elevated）; the other 3 patients were with decreased vocal parameters. The videostrobokynmography showed the recurrence in 1 patient, but not in others. In 4 cases with elevated vocal parameters, the videostrobokymography showed cycle-to-cycle variability of the amplitude, absence of vibration of vocal fold, glottal axis shift and phase difference . Conclusion:There are certain value of videostrobokymography in analyzing the minor changes of characteristic of vibration of vocal fold.

High speed digital videolaringoscopy: evaluation of vocal nodules and cysts in women / Videolaringoscopia digital de alta velocidade: avaliação de nódulos e cistos de pregas vocais de mulheres

ABSTRACT 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.

RESUMO Objetivo Avaliar e comparar os parâmetros da videoquimografia digital obtidos pela videolaringoscopia de alta velocidade de mulheres sem alterações laríngeas, de mulheres com nódulos de prega vocal e de mulheres com cistos vocais. Método Estudo observacional transversal, no qual foram selecionadas 60 mulheres com idade entre 18 e 45 anos. Três grupos foram formados: 20 mulheres sem alterações laríngeas formando o grupo controle (Grupo 1), 20 mulheres com diagnóstico de nódulos nas pregas vocais formando o Grupo 2 e 20 mulheres com diagnóstico de cistos vocais formando o Grupo 3. Posteriormente, os participantes foram avaliados por Videolaringoscopia de alta velocidade para análise e comparação de imagens da laringe usando videoquimografia digital. Os parâmetros videoquimográficos avaliados pelo programa KIPS® foram: aberturas mínima, máxima e média; amplitudes da prega vocal direita e esquerda; frequências da abertura da prega vocal direita e esquerda; e fechamento. Resultados A análise da videoquimografia digital sugere que a presença dos nódulos e dos cistos de pregas vocais tendem a restringir a abertura máxima e média da prega vocal e a amplitude dominante da variação de abertura na região média da glote. Conclusão Os parâmetros da videoquimografia digital foram semelhantes na presença de nódulos nas pregas vocais e lesões de cistos vocais.

Kymographic characteristics of voice in women with Polycystic ovary syndrome

ABSTRACT 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 variations in 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.

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.

Vibratory Onset of Adductor Spasmodic Dysphonia and Muscle Tension Dysphonia: A High-Speed Video Study✰.

OBJECTIVE: Adductor spasmodic dysphonia (AdSD) is a challenging voice disorder to diagnose, often erroneously diagnosed as muscle tension dysphonia (MTD) or vocal tremor, due to its similarity in auditory and perceptual presentation. Assessments using laryngoscopy or strobolaryngoscopy procedures have demonstrated limited utility in the diagnosis of spasmodic dysphonia. High-speed videoendoscopy (HSV) provides visualization of the precise vibratory pattern of phonatory onset and thus, offers an alternative to previous diagnostic strategies for visual diagnosis of AdSD. The purpose of this study was to examine vibratory onset of patients with AdSD and patients with MTD using HSV methodology. METHODS: HSV of six adults with AdSD and five adults with MTD were captured during sustained phonation. Digital kymography was used to obtain precise vibrogram data at the mid-membranous region of the vocal fold prior to and at the onset of phonation. Voice onset delay was examined by (1) quantifying timing of prephonatory delay and steady state delay and (2) describing vocal fold onset movements qualitatively in each diagnosis. RESULTS: HSV adequately captured the phonatory onset of the vocal folds. Voice onset delay was not significantly different between AdSD and MTD. However, there were distinct differences in voice onset gestures. Both AdSD and MTD patients presented with vocal hyperfunction during the onset of phonation. In a subset of AdSD patients, a rapid sustained adduction occurred following the initial vibratory motion. Vocal fold vibration then continued until steady phonation was achieved. This oscillatory break pattern was not observed in patients with MTD. Therefore, there appears to be differences in vocal fold vibratory onset motion between MTD and AdSD. CONCLUSION: HSV captures the precise vibratory onset in patients with MTD and AdSD. Differences were most notable after vibratory onset as opposed to vibratory delay measurements. Examination of voice onset gesture may offer an additional laryngeal parameter to assist in the differential diagnosis of spasmodic dysphonia.

Clinical Application of Two-Dimensional Scanning Digital Kymography in Discrimination of Diplophonia.

Purpose The purpose of this study was to investigate the characteristics of diplophonia using an auditory perception and multimodal simultaneous examination, which included sound waveform analysis, electroglottography (EGG), digital kymography (DKG), and 2-dimensional scanning digital kymography (2D DKG). Additionally, we compared the diagnostic accuracy of each method using a binary classifier in confusion matrix and convenience of discrimination, based on the time required for interpretation. Method One normophonic male, 12 patients with diplophonia, and 12 dysphonia patients without diplophonia were enrolled. A multimodal simultaneous evaluation was used to analyze the vibration pattern of diplophonia. Sensitivity, specificity, accuracy, area under the curve, and interpretation time were used to compare the various diagnostic methods. Discrimination was determined by 3 raters. Results There are 3 types of asymmetric vibratory patterns in diplophonia. The types are based on the oscillators vibrating at different frequencies: asymmetry of the left and right cords (6 subjects with unilateral palsy and 1 subject with vocal polyps), asymmetry of anterior and posterior cords (2 subjects with vocal polyps), and asymmetry of true and false cords (3 subjects with muscle tension dysphonia). All evaluation methods were useful as diagnostic tools, with all areas under the curve > .70. The diagnostic accuracy was highest with DKG (95.83%), followed by 2D DKG (83.33%), EGG (81.94%), auditory-perceptual evaluation (80.56%), and sound waveform (77.78%). The interpretation time was the shortest for auditory-perceptual evaluation (6.07 ± 1.34 s), followed by 2D DKG (10.04 ± 3.00 s), EGG (12.49 ± 2.76 s), and DKG (13.53 ± 2.60 s). Conclusions Auditory-perceptual judgment was the easiest and fastest method for experienced raters, but its diagnostic accuracy was lower than that of DKG or 2D DKG. The diagnostic accuracy of DKG was the highest, but 2D DKG allowed rapid interpretation and showed relatively high diagnostic accuracy, except in cases with space-occupying lesions. Supplemental Material https://doi.org/10.23641/asha.9911786.

Fundamental Frequency in Excised Human Larynges after Anterior Glottic Web Formation of Various Extents.

OBJECTIVE: To determine the effect of vocal fold anterior web formation on fundamental frequency with a cadaveric excised larynx model. STUDY DESIGN: Experimental study with excised human larynges. SETTING: Academic tertiary care hospital. SUBJECTS AND METHODS: Sixteen freshly excised human larynges were evaluated with high-speed videoendoscopy and digital kymography during artificially produced vibration. Each larynx was assessed in 4 conditions: preoperative controls and after 25%, 33%, and 50% decreases in the vibratory portion of the vocal folds. The following parameters were evaluated: fundamental frequency, periodicity, vocal fold vibration amplitude, phase symmetry, and glottic closure. RESULTS: The mean fundamental frequencies were 208.87, 250.20, 292.37, and 342.67 Hz for preoperative controls and 25%, 33%, and 50% reductions in vibratory length of the vocal folds, respectively. Fundamental frequency increased with each increase in anterior glottic web extent, and the difference among the groups was statistically significant in absolute values in hertz and in semitone elevation. The mathematical models for estimating postoperative fundamental frequency had a statistically significant coefficient. The vibration of the vocal folds remained periodic in all larynges before and after the procedures. CONCLUSION: There was a significant and progressive increase in the fundamental frequency with each enlargement of anterior glottic web. Based on the control frequency, mathematical models could estimate the value of the fundamental frequency after the procedure.

Vibratory Characteristics of Diplophonia Studied by High Speed Video and Vibrogram Analysis.

Diplophonia can occur in patients with polyps, atrophy, paralysis, or scars. Its vibratory patterns have not been well characterized. High-speed video (HSV) analysis can contribute to their understanding. Twenty subjects with a diplophonic voice quality were studied by HSV. Diplophonia was due to medical causes including vocal fold paresis (n = 7), vocal atrophy (n = 5), polyps (n = 5), and scars/sulci (n = 3). The HSV was analyzed using a multislice digital videokymography (DKG). The DKG tracing was analyzed qualitatively and then transformed into a vibrogram waveform signal for frequency analysis. RESULTS: Vibratory abnormalities seen on HSVs explained the diplophonia. Subharmonics to the fundamental frequency can be visualized by DKG. None could be resolved by stroboscopy. One can stratify diplophonia as symmetric or asymmetric based on the involvement of one or both vocal folds. Scars and atrophy showed symmetric subharmonic production with ectopic beats every 4-10 beats. Some subjects showed anterior and posterior independent vocal fold oscillators. Asymmetric causes of diplophonia are common in patients with paralysis. Two different oscillation frequencies of each vocal fold generate in and then out of phase interaction between the two sides. Vibrogram analysis documents the frequent presence of interharmonic energy peaks above the dominant fundamental frequency. Eighteen of the 20 subjects have obvious subharmonic peaks. CONCLUSION: Patients with diplophonia have vibratory abnormalities arising from the vocal folds. HSV and vibrogram analysis followed by frequency analysis of the vibrogram can resolve vibratory abnormality into symmetric versus asymmetric causes and can document the type of vibratory abnormality.

Usefulness of Two-Dimensional Digital Kymography in Patients With Vocal Fold Scarring.

OBJECTIVE: Although laryngeal videostroboscopy is widely utilized in the analysis of vocal fold vibrations, it is often difficult to identify patterns of vocal fold vibrations in patients with aperiodic voice signals due to failure of synchronization during laryngeal videostroboscopy examination. Therefore, the present study aimed to compare the usefulness of simultaneous two-dimensional digital kymography (2D DKG) and traditional DKG for the detection of changes in the pattern of vocal fold vibrations in patients with vocal fold scarring (VFS). METHODS: Seven patients with VFS and one normal subject underwent high-speed videoendoscopy (HSV). DKG and 2D DKG evaluations of vocal fold vibrations were performed simultaneously, following which both qualitative and quantitative analyses were performed. RESULTS: Simultaneous DKG and 2D DKG enabled observation of vibratory patterns as well as amplitude and phase symmetry. DKG revealed and provided temporal information regarding the pattern of vocal fold vibrations at sites of VFS. In contrast, 2D DKG provided real-time information regarding the pattern of vibrations for the whole vocal fold region and regions of increased stiffness, as well as spatial information regarding changes in this pattern. CONCLUSION: Our findings indicate that 2D DKG enables the assessment of overall vocal fold vibrations, regardless of periodicity, and that simultaneous DKG and 2D DKG can be used to confirm abnormal patterns of vocal fold vibrations in patients with impaired flexibility and elasticity of the vocal folds.

Evaluation of clinical value of videokymography for diagnosis and treatment of voice disorders.

This study aimed at determining the clinical value of videokymography (VKG) as an additional tool for the assessment of voice disorders. 105 subjects with voice disorders were examined by an experienced laryngologist. A questionnaire was used to specify diagnosis, diagnostic confidence, and treatment recommendations before and after VKG. The first part of questionnaire was filled by the laryngologist for each patient after routine ear-nose-throat evaluation, including stroboscopy, the second part after the subsequent VKG examination. In 31% of subjects VKG confirmed the stroboscopic diagnosis, in 44% it made the diagnosis more accurate, in 20% there was adjustment of the treatment, and in 5% it was not found diagnostically useful. After VKG the diagnostic confidence increased in 68% of the subjects. VKG may help clinicians to take some important treatment decisions and may be recommended to be performed in patients, where clinicians are uncertain about diagnosis and treatment.

Flexible Fiber-Optic High-Speed Imaging of Vocal Fold Vibration: A Preliminary Report.

OBJECTIVE: High-speed video (HSV) imaging of vocal fold vibration has been possible only through the rigid endoscope. This study reports that a fiberscope-based high-speed imaging system may allow HSV imaging of naturalistic voicing. MATERIALS AND METHODS: Twenty-two subjects were recorded using a commercially available black and white high-speed camera (Photron Motion Tools, 256 × 120 pixel, 2000 frames per second, 8 second acquisition time). The camera gain is set to +6 db. The camera is coupled to a standard fiber-optic laryngoscope (Olympus ENF P-4) with a 300-W Xenon light. Image acquisition was done by asking the subject to perform repeated phonation at modal phonation. Video images were processed using commercial video editing and video noise reduction software (After effects, Magix, and Neat Video 4.1). After video processing, the video images were analyzed using digital kymography (DKG). RESULTS: The HSV black and white video acquired by the camera is gray and lacks contrast. By adjustment of image contrast, brightness, and gamma and using noise reduction software, the flexible laryngoscopy image can be converted to video image files suitable for DKG and waveform analysis. The increased noise still makes edge tracking for objective analysis difficult, but subjective analysis of DKG plot is possible. CONCLUSIONS: This is the first report of HSV acquisition in an unsedated patient using a fiberscope. Image enhancement and noise reduction can enhance the HSV to allow extraction of the digital kymogram. Further image enhancement may allow for objective analysis of the vibratory waveform.

Vocal Fold Vibration Following Surgical Intervention in Three Vocal Pathologies: A Preliminary Study.

High-speed videoendoscopy captures the cycle-to-cycle vibratory motion of each individual vocal fold in normal and severely disordered phonation. Therefore, it provides a direct method to examine the specific vibratory changes following vocal fold surgery. The purpose of this study was to examine the vocal fold vibratory pattern changes in the surgically treated pathologic vocal fold and the contralateral vocal fold in three vocal pathologies: vocal polyp (n = 3), paresis or paralysis (n = 3), and scar (n = 3). Digital kymography was used to extract high-speed kymographic vocal fold images at the mid-membranous region of the vocal fold. Spectral analysis was subsequently applied to the digital kymography to quantify the cycle-to-cycle movements of each vocal fold, expressed as a spectrum. Surgical modification resulted in significantly improved spectral power of the treated pathologic vocal fold. Furthermore, the contralateral vocal fold also presented with improved spectral power irrespective of vocal pathology. In comparison with normal vocal fold spectrum, postsurgical vocal fold vibrations continued to demonstrate decreased vibratory amplitude in both vocal folds.