Digital Kymography Research Articles

Comparison of Vocal Amplitude and Contact Speed according to SOVTE Type

Objectives: Observation of vocal fold vibration during semi-occluded vocal tract exercises (SOVTE) can help in understanding voice production due to semi-occlusion. This study aimed to investigate the differences in vocal fold vibration characteristics among various types of SOVTE. This study may provide valuable evidence to support more specific and effective methods in applying SOVTE to voice therapy. Methods: A total of 10 healthy young adults (5 males, 5 females) with a mean age of 24.28±4.54 years participated in the study. None of the participants had any voice-related diseases or were smokers. The participants performed various types of SOVTE including humming, voiced bilabial fricative, straw phonation, and water-resistance straw phonation. The authors measured the amplitude and contact speed of vocal fold using a vibration simulator and digital kymography (DKG). Results: The results showed that vocal fold amplitude was not significantly different among types of SOVTE, but there were significant differences in vocal fold contact speed (p=.046). In multiple comparisons, vocal fold contact speed was significantly faster in humming (p=.031) and water-resistance straw phonation (p=.018) compared to straw phonation. Conclusion: The difference in vocal fold contact speed indicates that the vocal fold vibration during SOVTE is affected by the shape of the vocal tract. The use of humming and water-resistance straw phonation can be an effective approach to improve voice quality by increasing vocal fold contact speed, which is a key factor in determining overall voice quality. These two methods can be useful in voice therapy after laryngeal microsurgery. In the field, conducting trial therapy rather than applying voice therapy according to the hierarchy of SOVTE may lead to successful results.

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

Three healthy males and three healthy females were studied by simultaneous high-speed video laryngoscopy and recording with the production of the gesture [pa:pa:] at soft, medium, and loud voices. The fiber optic endoscope was threaded through a pneumotachograph mask for the simultaneous recording and analysis of acoustic and aerodynamic data. The average increase in the sound pressure level (SPL) for the group was 15 dB, from 70 to 85 dB. The fundamental frequency increased by an average of 10 Hz. The flow was increased in two subjects, reduced in two subjects, and remained the same in two subjects as the SPL increased. There was a steady increase in the subglottic pressure from soft to loud phonation. Compared to soft to medium phonation, a significant increase in glottal resistance was observed with medium-to-loud phonation. Videokymogram analysis showed the onset of vibration for all voiced tokens without the need for full glottis closure. In loud phonation, there is a more rapid onset of a larger amplitude and prolonged closure of the glottal cycle; however, more cycles are required to achieve the intended SPL. There was a prolonged closed phase during loud phonation. Fast Fourier transform (FFT) analysis of the kymography waveform signal showed a more significant second- and third-harmonic energy above the fundamental frequency with loud phonation. There was an increase in the adjustments in the pharynx with the base of the tongue tilting, shortening of the vocal folds, and pharyngeal constriction. Voice onset occurs in all modalities, without the need for full glottal closure. There was a more significant increase in glottal resistance with loud phonation than that with soft or middle phonation. Vibration analysis of the voice onset showed that more time was required during loud phonation before the oscillation stabilized to a steady state. With increasing SPL, there were significant variations in vocal tract adjustments. The most apparent change was the increase in tongue tension with posterior displacement of the epiglottis. There was an increase in pre-phonation time during loud phonation. Patterns of muscle tension dysphonia with laryngeal squeezing, shortening of the vocal folds, and epiglottis tilting with increasing loudness are features of loud phonation. These observations show that flexible high-speed video laryngoscopy can reveal observations that cannot be observed with rigid video laryngoscopy. An objective analysis of the digital kymography signal can be conducted in selected cases.

Multivariate Analysis of Vocal Fold Vibrations in Normal Speakers Using High-Speed Digital Imaging.

Little is known about the normal variations in vocal fold vibrations. We conducted a prospective study on normal subjects using high-speed digital imaging (HSDI) to elucidate key parameters regarding age/gender-related normal variations. Forty-six healthy adult volunteers were divided into young (aged ≤35 years) male, young female, elderly (aged ≥65 years) male, and elderly female subgroups. HSDI data of sustained phonation of /i/ at a comfortable pitch and loudness were obtained, and vibratory parameters were calculated using the visual-perceptual rating, laryngotopography, digital kymography, and glottal area waveform. Multivariate analysis was then performed on these parameters to clarify the subgroup-specific key parameters. Four key parameters were identified from a total of 83: one from visual perceptual rating and three from laryngotopography. Subgroup analyses showed that posterior-to-anterior longitudinal phase difference (PD) and high fundamental frequency (F0) were specific to young female participants. A low F0 was specific to young male participants. Large anterior-to-posterior longitudinal PD and its left-right difference were specific to elderly male participants. There were no key parameters for elderly female participants. Methods that can assess F0 and longitudinal PD, such as visual-perceptual rating and laryngotopography, were effective in the evaluation of normal vocal fold vibrations and their variations.

Comparação entre a frequência fundamental acústica da voz e a frequência de vibração das pregas vocais analisada pela videoquimografia digital

ABSTRACT 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.

Reabilitação vocal em cantoras com queixa vocal: análise da videoquimografia digital

ABSTRACT Purpose: to evaluate the effects of the Comprehensive Vocal Rehabilitation Program associated with the application of transcutaneous electrical nerve stimulation through digital kymography in singers with vocal complaints. Methods: an experimental intrasubject comparative study in 24 singers, who underwent the rehabilitation program associated with transcutaneous electrical nerve stimulation. They were assessed with laryngeal high-speed videoendoscopy before and after vocal rehabilitation. The paired t-test and Wilcoxon test were used to compare the two assessments. The significance level was set at 5%. Results: significant differences were found in the maximum opening, dominant amplitude of the opening variation and dominant frequency of the opening variation of the right vocal fold in the posterior glottic region, and in maximum opening, mean opening, dominant amplitude of the opening variation of the left vocal fold and dominant frequency of the opening variation of both vocal folds in the anterior glottic region. Conclusion: the results showed that the Comprehensive Vocal Rehabilitation Program associated with transcutaneous electrical stimulation decreased the opening amplitude of the vocal fold, increased the vibration frequency, and improved glottal closure in the anterior and posterior glottic regions.

Vocal rehabilitation in singers with vocal complaints: a digital kymography analysis

RESUMO Objetivo: avaliar os efeitos do Programa Integral de Reabilitação Vocal associado à aplicação da estimulação elétrica nervosa transcutânea por meio da videoquimografia digital em cantoras com queixa vocal. Métodos: estudo experimental comparativo intrassujeitos com 24 cantoras, que realizaram o programa de reabilitação associado à estimulação elétrica nervosa transcutânea. A avaliação, por meio da videolaringoscopia de alta velocidade, foi realizada antes e após a reabilitação vocal. Os testes T pareado e de Wilcoxon foram utilizados para comparação das duas avaliações. Considerou-se o nível de significância de 5%. Resultados: diferenças significantes foram identificadas quanto aos parâmetros de abertura máxima, amplitude dominante de variação de abertura e frequência dominante de abertura da prega vocal direita na região posterior da glote, além dos parâmetros de abertura máxima, abertura média, amplitude dominante de variação de abertura da prega vocal esquerda e frequência dominante de abertura de ambas as pregas vocais na região anterior da glote. Conclusão: os resultados mostraram que o Programa Integral de Reabilitação Vocal associado à estimulação elétrica transcutânea promoveu uma diminuição da amplitude de abertura da prega vocal e aumento da frequência de vibração, além de um melhor fechamento glótico nas regiões anterior e posterior da glote.

A Quantitative Examination of Vocal Fold Vibratory Changes Using Two-Dimensional Scanning Digital Kymography After Angiolytic Laser Stripping for Vocal Fold Leukoplakia

Background and Objectives Vocal fold leukoplakia is characterized as white plaque on the epithelium of the vocal folds and can be treated by angiolytic laser stripping surgery. However, postoperative changes in the vibratory patterns of vocal folds have not been investigated quantitatively. The purpose of this study was to investigate the changes in vocal fold vibration after angiolytic laser surgery in patients with unilateral vocal fold leukoplakia using the twodimensional scanning digital kymography (2D DKG).Subjects and Method Medical records of seven males (age=62.14±12.40 yrs) with unilateral vocal fold leukoplakia who underwent angiolytic laser stripping were reviewed. Before and after the surgery (post-operative day=82.57±28.55 days), a multi-dimensional voice assessment was performed along with a 2D DKG study. For 2D DKG images, the amplitude symmetry index (ASI), phase symmetry index (PSI), and open quotient (OQ) were calculated using the ImageJ program. In addition, pre- versus postoperative data were compared, and the correlation between the changes in 2D DKG parameters and voice outcomes was explored.Results Results indicated that the absolute ASI (<i>p</i>=0.028) and OQ (<i>p</i>=0.028) of the 2D DKG study, grade (<i>p</i>=0.038) and breathy (<i>p</i>=0.034) of the GRBAS scale, σPitch measured by the electroglottography (<i>p</i>=0.043), the physical score of the VHI (<i>p</i>=0.042), and the total score (<i>p</i>=0.043) and the tiredness score (<i>p</i>=0.043) of the VFI decreased after surgery. Decrease in the absolute ASI was correlated with changes in the grade (rho=0.850) and breathy (rho=0.777) scale measures, while decreased OQ were correlated with the changes in the physical score of the VHI (rho=0.901) and tiredness score of the VFI (rho=0.847).Conclusion The improved vocal fold vibratory patterns after angiolytic laser surgery for vocal fold leukoplakia can be evaluated objectively using the 2D DKG study. Angiolytic laser stripping enables the preservation of vocal fold vibration after the surgery and is considered a valuable surgical option for treating vocal fold leukoplakia.

Vocal Fold Vibration Characteristics during SOVTE using a Vibration Simulator and Digital Kymography

Objectives: The purpose of this study is to investigate the characteristics of vocal fold vibration during sustained vowel /a/ phonation and various semi-occluded vocal tract exercise (SOVTEs) using a vibration simulator and digital kymography (DKG).Methods: A total of 12 normal young speakers (6 males, 6 females) aged 20-30 years participated in the study. They phonated a sustained /a/ vowel and performed SOVTE. The vocal fold vibration characteristics were measured according to the number of vibration sources (single vs. double), and vocal tract occlusion degree using a vibration simulator and DKG. Glottal gap quotient (GQ, %), speed quotient (SQ, %) and amplitude (pixel) were estimated quantitatively from the DKG image.Results: The results showed that significantly higher GQ (p = .000) and SQ (p = .000) were observed in the humming and bilabial fricative /β/ compared to open vowels. The amplitude was significantly higher in the open vowel /a/ than in humming (p = .018) and bilabial fricative /β/ (p = .003). Also, when comparing the vocal fold vibration parameters according to vibration type (single source: straw phonation vs. double source: straw phonation with water), the double source presented a significantly higher GQ (p = .000) as well as SQ (p = .008) in comparison with a single source.Conclusion: SOVTE showed a glottal gap that is different from the opened vowel /a/. It also had a longer opening of the vocal fold and a smaller amplitude than the vowel. This suggests that SOVTE may be helpful for facilitating vocal fold vibration and good voice quality in clinical practice. The current study can be meaningful in providing theoretical and clinical evidence for SOVTE.

Multivariate Analysis of Vocal Fold Vibrations on Various Voice Disorders Using High-Speed Digital Imaging

Although many quantitative parameters have been devised to describe abnormalities in vocal fold vibration, little is known about the priority of these parameters. We conducted a prospective study using high-speed digital imaging to elucidate disease-specific key parameters (KPs) to characterize the vocal fold vibrations of individual voice disorders. From 304 patients with various voice disorders and 46 normal speakers, high-speed digital imaging of a sustained phonation at a comfortable pitch and loudness was recorded and parameters from visual-perceptual rating, laryngotopography, digital kymography, and glottal area waveform were calculated. Multivariate analysis was then applied to these parameters to elucidate the KPs to explain each voice disorder in comparison to normal subjects. Four key parameters were statistically significant for all laryngeal diseases. However, the coefficient of determination (R2) was very low (0.29). Vocal fold paralysis (8 KPs, R2 = 0.76), sulcus vocalis (4 KPs, R2 = 0.74), vocal fold scarring (1 KP, R2 = 0.68), vocal fold atrophy (6 KPs, R2 = 0.53), and laryngeal cancer (1 KP, R2 = 0.52) showed moderate-to-high R2 values. The results identified different KPs for each voice disorder; thus, disease-specific analysis is a reasonable approach.

Recent Advances in Examination of Vocal Fold Vibration

Human vocal cords vibrate as quickly as 100–250 times per second, so it is impossible to observe them with normal endoscopic diagnostic equipment. High-speed videolaryngoscopy (HSV) allows the visualization of non-periodic vibratory motion of vocal fold beyond the limitation of videostroboscopy. New developed post-processing methods that converts HSV to two-dimensional videokymography (2D VKG) using U-medical image-processing software can provide quantitative information on vocal fold mucosa vibration. Multifunctional laryngeal examination system is composed of 3 kinds of examinations such as HSV, 2D scanning digital kymography (2D DKG) and line scanning digital kymography (DKG). Evaluation of entire vocal cord vibratory pattern in each cord is possible using 2D DKG and a faster and more reliable quantitative information can be obtained. As this system is used in clinical and research, it is expected to bring much advances to the diagnosis of voice disorders. In this review, I will introduce the principles and advantages on examination of the vocal fold vibration, which is in the spotlight recently, and proceed with the literature review. Key words: Vocal cords ㆍ Vibration ㆍ Stroboscopy ㆍ Kymography 핵심용어: 성대 ㆍ 진동 ㆍ 스트로보스코피 ㆍ 카이모그래피

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

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. 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. 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. 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.

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

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

Objective Measures of Stroboscopy and High-Speed Video.

Videostroboscopy and high-speed imaging is now an accepted way to evaluate laryngeal function in patients with voice disorders. In patients with neurolaryngological diseases such as tremor, laryngeal spasm, and paralysis, having an objective way to evaluate vocal function is desirable. Using digital imaging and analysis, both the videostroboscopy and the high-speed video can be analyzed to obtain relevant measures of vocal function. From the videostroboscopy, the montage of the glottal cycle derived from steady of vocal vibration can be analyzed by using edge tracking software to obtain the glottal area waveform. The waveform is an indication of the efficiency of the vocal folds in acting as an oscillator and gives direct information as to the open and closed phase, the symmetry of vocal fold vibration and the degree of amplitude contribution from each fold. High-speed video overcomes the deficiencies of stroboscopy by allowing for all voice gestures to be studies. Using digital kymography and analysis of the vibrogram, analysis of the onset of vocal fold oscillation, evaluation of diplophonia, tremor, and voice breaks becomes possible. Furthermore, analysis of the high-speed video kymograph tracing using signal analysis allow the investigator to evaluate the frequency and power relationships of vocal fold vibratory function in the normal and disordered state.

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

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. 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. 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. 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.

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

To determine the effect of vocal fold anterior web formation on fundamental frequency with a cadaveric excised larynx model. Experimental study with excised human larynges. Academic tertiary care hospital. 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. 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. 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.

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

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). 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. 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. 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.

Efficacy of Two-dimensional Scanning Digital Kymography in Evaluation of Atrophic Vocal Folds

The purpose of this study was to evaluate the clinical feasibility and diagnostic accuracy of two-dimensional scanning digital kymography (2D DKG) in patients with vocal cord atrophy before and after treatment. We analyzed the characteristics of vocal fold vibration in five patients with unilateral vocal fold paralysis and five patients with presbyphonia. In patients with vocal cord paralysis, the status before and after intracordal injection was compared. Furthermore, in patients with presbyphonia, we compared the status before and after voice therapy (Seong-Tae Kim's laryngeal calibration technique). Quantitative parameters such as amplitude and phase symmetry indices, jitter, shimmer, noise-to-harmonic ratio, and maximum phonation time and qualitative parameters such as Voice Handicap Index, glottal gap, amplitude, and phase difference were used to evaluate the pre- and post-treatment status. In cases of vocal cord paralysis, vibratory changes of the vocal folds before and after intracordal injection could be identified immediately using 2D DKG. In overcorrection cases, all of the measured parameters were poor except for improvement of the glottal gap. In addition, 2D DKG showed appropriately the changes in vocal cord vibration before and after voice therapy in patients with presbyphonia. Two-dimensional DKG may be a useful diagnostic tool in evaluation of the vibratory characteristics of entire vocal cords. In addition, it may also play a role in providing a decision for treatment modalities.

성대의 미세 진동 변화 감별에 라인 스캐닝과 평면 스캐닝 디지털 카이모그래피의 유용성 비교 : 증례 보고

성대의 미세 진동 변화 감별에 라인 스캐닝과 평면 스캐닝 디지털 카이모그래피의 유용성 비교 : 증례 보고

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.

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

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. 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). 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. 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.