Papers by Ken-ichi Sakakibara
Journal of Voice, 2014
Glottal area waveform (GAW) analysis is widely used in the assessment of vocal fold vibration by ... more Glottal area waveform (GAW) analysis is widely used in the assessment of vocal fold vibration by high-speed digital imaging (HSDI). Because normative GAW data obtained from a large number of subjects have not been reported, we conducted a prospective study to obtain normative results for GAW analysis of HSDI findings and clarify normal variations associated with gender and age. Vocally healthy adults were divided into a young group (aged ≤ 35 years) and an elderly group (aged ≥ 65 years). The configuration and size of the glottal area were assessed at different phases of the glottal cycle, and gender- and age-related differences were evaluated. A total of 26 young subjects (nine men and 17 women; mean age: 27 years) and 20 elderly subjects (eight men and 12 women; mean age: 73 years) were investigated. The glottal area at different points of the glottal cycle showed a negative correlation with frequency. Although the GAW parameters of young women appeared to be different from those of the other subgroups, the differences were not statistically significant. Young women predominantly had a triangular- or vase-shaped glottal configuration at all frequencies, whereas the other subgroups showed various glottal shapes. The present study clarified gender- and age-related differences of GAW parameters obtained with HSDI. Young women were likely to show different glottal configurations and different responses to frequency changes from those of young men, elderly men, and elderly women. Phonosurgeons should pay attention to the normal variations detected in the present study.
Acoustical Science and Technology, 2013
Asian traditional pressed-type singing voices are different from the European traditional singing... more Asian traditional pressed-type singing voices are different from the European traditional singing voice in their timbre and voice production mechanism. In throat singing, the ventricular folds and true vocal folds vibrate, resulting in the generation of the special laryngeal voice. On the other hand, in some other pressed-type singing voices, such as Japanese Min-yoh, the ventricular folds only approximate but do not vibrate. We propose a new laryngeal flow model incorporating the effect of the ventricular fold vibration and laryngeal ventricle resonance. The model is a combination of the known glottal airflow model (R-model), the laryngeal ventricle resonance (Helmholtz resonator), and the modulation of ventricular fold vibration. We will also demonstrate the relation between model parameters and voice quality. The results show that the proposed model is effective for synthesizing the pressed-type singing voices.
Journal of Speech Language and Hearing Research, 2014
PURPOSE In this study, the authors aimed to analyze longitudinal data from high-speed digital ima... more PURPOSE In this study, the authors aimed to analyze longitudinal data from high-speed digital images in normative subjects using multi-line kymography. METHOD Vocally healthy subjects were divided into young (9 men and 17 women; Mage = 27 years) and older groups (8 men and 12 women; Mage = 73 years). From high-speed digital images of phonation at a conversational frequency kymograms were created at 5 different levels of the vocal fold and were analyzed to determine the opening/closing longitudinal phase difference, open quotient, and speed index. Then age- and gender-related differences of these parameters were analyzed statistically. RESULTS Young women frequently showed a pattern of posterior-to-anterior glottal opening and anterior-to-posterior glottal closure, and older women demonstrated various opening and closing patterns. Both young men and older men were similar to older women. The open quotient was maximal at the most posterior glottal level in young women, but it tended to be maximal at the anterior glottis in the other subgroups. The mean value of the 5 open quotients was largest in young women. The mean speed index had a large negative value in older subjects. CONCLUSION This study provides the first information about age-related differences of longitudinal oscillatory characteristics of the vocal folds obtained with high-speed digital imaging.
Journal of Voice, 2015
To explore the method to visualize and quantify the abnormality of vocal fold vibration in vocal ... more To explore the method to visualize and quantify the abnormality of vocal fold vibration in vocal fold scar (VFS) using high-speed digital imaging (HSDI). HSDI was performed on 12 patients (2 men and 10 women) with VFS and 46 vocally healthy subjects (17 men and 29 women), and the obtained data were quantitatively evaluated by frame-by-frame analysis, laryngotopography (LTG), single-line and multiline kymography, and glottal area waveform. Visualization of a scarred area was feasible in 75% of VFS in the present study using LTG. Quantitative HSDI analysis revealed that VFS had poorer glottal closure (eg, larger open quotients, larger minimal glottal area), reduced vibration in a scarred area (eg, smaller mucosal wave magnitude, mucosal wave persistence, lateral peak index), and greater asymmetry (eg, amplitude difference, mucosal wave magnitude difference, lateral phase difference) than the control group. Correlation study revealed moderate correlations between HSDI-derived parameters and conventional acoustic or aerodynamic parameters (eg, period perturbation quotient). HSDI is considered to be useful in the diagnosis of VFS, visualization of a scarred area, and quantification of vibratory abnormality.
A laryngeal flow model with many parameters is described. This model consists of a glottal flow m... more A laryngeal flow model with many parameters is described. This model consists of a glottal flow model, laryngeal ventricle resonator, and supraglottal modulator. The model is capable of representing various laryngeal airflows even when they are accompanied by supraglottal constriction and vibrations, such as found in throat singing, growl, and harsh voices. The proposed model contains several parameters related to
Annual Conference of the International Speech Communication Association, 2010
In this paper, a novel stereo-endoscopic high-speed digital imaging system and a method to estima... more In this paper, a novel stereo-endoscopic high-speed digital imaging system and a method to estimate the glottal area function are proposed. Glottal length, width, and area of one female participant were estimated in three different fundamental frequencies (F 0 s).
Journal of The Acoustical Society of America, 2002
Throat singing is a traditional singing style of people who live around the Altai Mountains. Khoo... more Throat singing is a traditional singing style of people who live around the Altai Mountains. Khoomei in Tyva and Khoomij in Mongolia are representative styles of throat singing. The laryngeal voices of throat singing is classified into (i) a drone voice which is the basic laryngeal voice in throat singing and used as drone and (ii) a kargyraa voice which
Annual Conference of the International Speech Communication Association, 2010
Journal of The Acoustical Society of America, 2002
Phonation is the vocal fold vibration on normal voice. But sometimes we can observe the other pho... more Phonation is the vocal fold vibration on normal voice. But sometimes we can observe the other phonation styles like as the pressed voice or some throat singings like as ''kargyraa'' or ''drone'' in Khoomei in Mongolian music. Also, clinically, we know that some patients who have the wide glottal slit in phonation because of the recurrence nerve palsy or after
Journal of The Acoustical Society of America, 2002
The physiological study of prosody is indispensable in terms not only of the physiological intere... more The physiological study of prosody is indispensable in terms not only of the physiological interest but also of the evaluation and treatment for pathological cases of prosody. In free talk, the changes of vocal fold vibration are found frequently and these phenomena are very important prosodic events. To analyze quantitatively the vocal fold vibration at the register change as the
We observed laryngeal movements in throat singing using physiological methods: the simultaneous r... more We observed laryngeal movements in throat singing using physiological methods: the simultaneous recording of singing sounds, EGG, and high-speed digital images. We observed vocal fold and false vocal fold vibration and estimated the vibration patterns. We also estimated the laryngeal voices by using an inverse filtering method and simulated the vibration pattern using a new physical model: 2 ×2-mass model.
The timbre of the singing voice is strongly affected by the shapes of the laryngeal tube and hypo... more The timbre of the singing voice is strongly affected by the shapes of the laryngeal tube and hypopharynx. We propose a physical model of the vocal tract and larynx, including the vocal and ven- tricular folds, for synthesis. We study the effect of the shapes of the laryngeal tube and hypopharynx on the synthesized voice using the proposed model. We
Singing voices have various timbres. Throat singing and some other Asian traditional singing voic... more Singing voices have various timbres. Throat singing and some other Asian traditional singing voices have a pressed timbre that is significantly different from the European clas- sic singing voice. In our previous study on throat singing, the vibration of the false vocal folds as well as that of the vocal folds was observed and was found to be essentially due
Journal of Voice, 2015
In the present study, we examined the relationship between various open quotients (Oqs) and phona... more In the present study, we examined the relationship between various open quotients (Oqs) and phonation types, fundamental frequency (F0), and intensity by multivariate linear regression analysis (MVA) to determine which Oq best reflects vocal fold vibratory characteristics. Using high-speed digital imaging (HSDI), a sustained vowel /e/ at different phonation types, F0s, and intensities was recorded from six vocally healthy male volunteers: the types of phonation included modal, falsetto, modal breathy, and modal pressed phonations; and each phonation was performed at different F0s and intensities. Electroglottography (EGG) and sound signals were simultaneously recorded with HSDI. From the obtained data, 10 conventional Oqs (four Oqs from the glottal area function, four kymographic Oqs, and two EGG-derived Oqs) and two newly introduced Oqs [Formula: see text] were evaluated. And, relationships between various Oqs and phonation types, F0, and intensity were evaluated by MVA. Among the various Oqs, [Formula: see text] revealed the strongest correlations with an acoustic property and could best describe changes in phonation types: [Formula: see text] was found to be better than Oq(edge)¯. Oq(MLK), the average of five Oqs from five-line multiline kymography was a very good alternative to Oq(edge)¯. EGG-derived Oqs were able to differentiate between modal phonation and falsetto phonation, but it was necessary to consider the change of F0 simultaneously. MVA showed the changes in Oq values between modal and other phonation types, the degree of involvement of intensity, and no relationship between F0 and Oqs. Among Oqs evaluated in this study, [Formula: see text] were considered to best reflect the vocal fold vibratory characteristics.
Nihon Rinsho Geka Gakkai Zasshi (Journal of Japan Surgical Association), 2007
Journal of Voice, 2015
To quantify vibratory characteristics of various laryngeal disorders seen by high-speed digital i... more To quantify vibratory characteristics of various laryngeal disorders seen by high-speed digital imaging (HSDI). HSDI was performed on 78 patients with various laryngeal disorders (20 with polyp, 16 with carcinoma, 13 with leukoplakia, 6 with vocal fold nodule, and 33 with others) and 29 vocally healthy subjects. Obtained data were quantitatively evaluated by frame-by-frame analysis, laryngotopography, digital kymography, and glottal area waveform. Overall, patients with laryngeal pathologies showed greater asymmetry in amplitude, mucosal wave and phase, smaller mucosal wave, and poorer glottal closure than vocally healthy subjects. Furthermore, disease-specific vibratory disturbances that generally agreed with the findings in the literature were quantified: comparing polyp with nodule, differences were noted in longitudinal phase difference, amplitude, and mucosal wave. In comparison with leukoplakia and cancer, nonvibrating area was more frequently noted in cancer. The HSDI analysis of various voice disorders using multiple methods can help phonosurgeons to properly diagnose various laryngeal pathologies and to estimate the degree of their vocal disturbances.
Journal of voice : official journal of the Voice Foundation, 2015
Kymography is an effective method for assessing temporal patterns of vocal fold vibrations. Becau... more Kymography is an effective method for assessing temporal patterns of vocal fold vibrations. Because kymographic data for a number of normal speakers based on high-speed digital imaging (HSDI) were limited in the literature, this prospective study was conducted to provide normative kymographic HSDI data and clarify gender- and age-related normal variations. Vocally healthy adults were divided into young (≤35 years) and elderly groups (≥65 years). Kymograms were recomposed from HSDI data at the midglottal level, and kymographic parameters were analyzed quantitatively. Then gender- and age-related differences were evaluated. A total of 26 young subjects (9 men and 17 women, mean age: 27 years) and 20 elderly subjects (8 men and 12 women, mean age: 73 years) were investigated. Obtained data generally matched the values in the literature. Slight asymmetry was seen in all groups, with the elderly subjects having more evident asymmetry than the young subjects. Most of the kymographic param...
The Journal of the Acoustical Society of America, 2014
Despite being an indispensable tool for both researchers and clinicians, traditional endoscopic i... more Despite being an indispensable tool for both researchers and clinicians, traditional endoscopic imaging of the human vocal folds is limited in that it cannot capture their inferior-superior motion. A three-dimensional reconstruction technique using high-speed video imaging of the vocal folds in stereo is explored in an effort to estimate the inferior-superior motion of the medial-most edge of the vocal folds under normal muscle activation in vivo. Traditional stereo-matching algorithms from the field of computer vision are considered and modified to suit the specific challenges of the in vivo application. Inferior-superior motion of the medial vocal fold surface of three healthy speakers is reconstructed over one glottal cycle. The inferior-superior amplitude of the mucosal wave is found to be approximately 13 mm for normal modal voice, reducing to approximately 3 mm for strained falsetto voice, with uncertainty estimated at σ ≈ 2 mm and σ ≈ 1 mm, respectively. Sources of error, and...
Journal of Voice, 2014
Glottal area waveform (GAW) analysis is widely used in the assessment of vocal fold vibration by ... more Glottal area waveform (GAW) analysis is widely used in the assessment of vocal fold vibration by high-speed digital imaging (HSDI). Because normative GAW data obtained from a large number of subjects have not been reported, we conducted a prospective study to obtain normative results for GAW analysis of HSDI findings and clarify normal variations associated with gender and age. Vocally healthy adults were divided into a young group (aged ≤ 35 years) and an elderly group (aged ≥ 65 years). The configuration and size of the glottal area were assessed at different phases of the glottal cycle, and gender- and age-related differences were evaluated. A total of 26 young subjects (nine men and 17 women; mean age: 27 years) and 20 elderly subjects (eight men and 12 women; mean age: 73 years) were investigated. The glottal area at different points of the glottal cycle showed a negative correlation with frequency. Although the GAW parameters of young women appeared to be different from those of the other subgroups, the differences were not statistically significant. Young women predominantly had a triangular- or vase-shaped glottal configuration at all frequencies, whereas the other subgroups showed various glottal shapes. The present study clarified gender- and age-related differences of GAW parameters obtained with HSDI. Young women were likely to show different glottal configurations and different responses to frequency changes from those of young men, elderly men, and elderly women. Phonosurgeons should pay attention to the normal variations detected in the present study.
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Papers by Ken-ichi Sakakibara