• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.13 no.2
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• pp.139-144
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• 2002

Background and objectives : The various voice-conserving treatments are used for Tla staged glottic cancer. Especially, Tla staged glottic cancer has been shown excellent treatment result after laser cordectomy or radiotherapy. To evaluate which treatment results better voice after treatment made it valuable to define the exact indication and recommending treatment modality on the Tla staged glottic cancer patients. Method : The medical records of 75 patients with glottic TlaN0 cancer diagnosed at Asan medical center, University of Ulsan college of medicine form May, 1989 to July,2001 were retrospectively reviewed on the point of voice quality and oncology including 5-year survival rate and local control rate. Results : Laser cordectomy and radiotherapy showed 100% and 94.0% 5-year survival rate, respectively. And laser cordectomy had 94.3% local control rate while radiotherapy got 87.6% local control rate. Voice analysis of pretreatment and posttreatment were used to compare each result. Fundamental frequency(F0), shimmer, jitter, noise to harmony ratio(NHR), maximum confortable phonation time(MPT) and vocal efficiency(VE) were used for parameters for voice analysis. Only in shimmer and MPT, we could find significant posttreatment difference between two therapies. In addition, we reviewed the total expenses for each therapy. Conclusion : On the basis of the oncologic result, both the laser cordectomy and radiotherapy had the similar results. Laser cordectomy showed the relatively acceptable voice as radiotherapy did. Laser cordectomy cost less than radiotherapy did. Laser cordectomy can be used for treatment about Tla staged glottic cancer.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.13 no.2
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• pp.155-163
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• 2002

Background and Objectives : Esophageal voice, Silicone voice Prosthesis with tracheo-esophageal (T-E) puncture have been used as vocal rehabilitation methods for postlaryngectomy. However, long-term follow-up in the voice rehabilitation in the total laryngectomees has not been reported. The purpose of this study is to analyze practice of postlaryngectomy voice rehabilitation and to find the effective voice rehabilitation. Materials and Methods : From Jan 1992 until June 2002, 75 patients underwent a total laryngectomy at Yongdong Severance Hospital. We retrospectively studied voice rehabilitation methods commonly used, acquisition levels of esophageal speech, patients satisfaction scale (5 rating scale) according to the methods in 33 of them (40 died, 2 unavailable) by using charts review, telephone interview. Results : T-E speech is most commonly used by 14 patients (42.4%) : A tracheo-esophageal procedure (primary or secondary puncture) by 21 : and 8 patients removed Provox. 1 patient had no voice rehabilitation. 7 patients (21.2%) have used esophageal speech : 4 patients of them have used it after removing Provox. Electrolarynx has been used with other voice rehabilitation methods : 4 patients have only used this method and 3 patients with T-E speech, 1 patient with esophageal speech. However, 6 patients (18%) remained without a substitute voice rehabilitation. In the satisfaction with speech and management of voice rehabilitation methods, patients using esophageal speech were most satisfied (4.1), patients with T-E speech were unsatisfied (2.3). Regarding with the acquisition level of esophageal speech in 33 patients, 22 patients (66.6%) failed without functional speech. Conclusion : To increase patients satisfaction and to achieve successful voice rehabilitation after total laryngectomy, preoperative counseling, pretesting, appropriate patient selection of each method and team decision-making and postoperative voice therapy must be considered.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.18 no.2
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• pp.96-101
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• 2007

Laryngopharyngeal reflux (LPR) is the retrograde movement of gastric contents into the larynx, pharynx, and upper aero-digestive tract. LPR differs from gastroesophageal reflux in that it is often not associated with heartburn and regurgitation symptoms. Otolaryngological manifestations of acid reflux include a wide range of pharyngeal and laryngeal symptoms. Belafsky et al. developed a useful self-administered tool, the reflux symptom index (RSI), for assessing the degree of LPR symptoms. Patients are asked to use a 0 to 5 point scale to grade the following symptoms: 1) hoarseness or voice problems; 2) throat clearing; 3) excess throat mucus or postnasal drip ; 4) difficulty swallowing; 5) coughing after eating or lying down; 6) breathing difficulties ; 7) troublesome or annoying cough; 8) sensation of something sticking or a lump in the throat; 9) heartburn, chest pain, indigestion or stomach acid coming up. A RSI score greater than 13 is considered abnormal. As there is no validated instrument to document the physical findings and severity of LPR, Belafsky et al. developed an eight-item clinical severity scale for judging laryngoscopic finding, the reflux finding score (RFS). They rated eight LPR-associated findings on a scale from 0 to 4 : subglottic edema, ventricular obliteration, erythema/hyperemia, vocal-fold edema, diffuse laryngeal edema, posterior commissure hypertrophy, granuloma/granulation tissue, and thick endolaryngeal mucus. A RFS score of greater than 7 was found to suggest LPR-associated laryngitis. Although both indices (RSI and RFS) are widely used, there is some controversy about their validity (sensitivity and specificity) and reliability (intra-rater and inter-rater) in LPR diagnosis and treatment. We discuss the validity and reliability of RSI and RFS with literature review.

• The Journal of the Acoustical Society of Korea
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• v.22 no.4
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• pp.299-307
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• 2003

There have been many studies on speaker normalization which aims to minimize the effects of speaker's vocal tract length on the recognition performance of the speaker independent speech recognition system. In this paper, we propose a simple vector quantizer based linear warping speaker normalization method based on the observation that the vector quantizer can be successfully used for speaker verification. For this purpose, we firstly generate an optimal codebook which will be used as the basis of the speaker normalization, and then the warping factor of the unknown speaker will be extracted by comparing the feature vectors and the codebook. Finally, the extracted warping factor is used to linearly warp the Mel scale filter bank adopted in the course of MFCC calculation. To test the performance of the proposed method, a series of recognition experiments are conducted on discrete HMM with thirteen mono-syllabic Korean number utterances. The results showed that about 29% of word error rate can be reduced, and that the proposed warping factor extraction method is useful due to its simplicity compared to other line search warping methods.

• The Journal of the Acoustical Society of Korea
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• v.31 no.2
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• pp.93-99
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• 2012

For speech coding, a vocal tract is modeled using Linear Predictive Coding (LPC) coefficients. The LPC coefficients are typically transformed to Line Spectral Frequency (LSF) parameters which are advantageous for linear interpolation and quantization. If multidimensional LSF data are quantized directly using Vector-Quantization (VQ), high rate-distortion performance can be obtained by fully utilizing intra-frame correlation. In practice, since this direct VQ system cannot be used due to high computational complexity and memory requirement, Split VQ (SVQ) is used where a multidimensional vector is split into multilple sub-vectors for quantization. The LSF parameters also have high inter-frame correlation, and thus Predictive SVQ (PSVQ) is utilized. PSVQ provides better rate-distortion performance than SVQ. In this paper, to implement the optimal predictors in PSVQ for voice storage devices, we propose Multi-Frame AR-model based SVQ (MF-AR-SVQ) that considers the inter-frame correlations with multiple previous frames. Compared with conventional PSVQ, the proposed MF-AR-SVQ provides 1 bit gain in terms of spectral distortion without significant increase in complexity and memory requirement.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.5
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• pp.62-70
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• 2000

In this study, speech recognition for Korean digit is performed using filter bank which is programmed discrete HMM and DTW. Spectral analysis reveals speech signal features which are mainly due to the shape of the vocal tract. And spectral feature of speech are generally obtained as the exit of filter banks, which properly integrated a spectrum at defined frequency ranges. A set of 8 band pass filters is generally used since it simulates human ear processing. And defined frequency ranges are 320-330, 450-460, 640-650, 840-850, 900-1000, 1100-1200, 2000-2100, 3900-4000Hz and then sampled at 8kHz of sampling rate. Frame width is 20ms and period is 10ms. Accordingly, we found that the recognition rate of DTW is better than HMM for Korean digit speech in the experimental result. Recognition accuracy of Korean digit speech using filter bank is 93.3% for the 24th BPF, 89.1% for the 16th BPF and 88.9% for the 8th BPF of hardware realization of voice dialing system.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1982.05a
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• pp.12-12
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• 1982

We have recently experienced a case of decannulation difficulty resulted from head and thoracic injury. The patient was 21-year-old male who undergone craniectomy and tracheotomy at other hospital about 7 months ago prior to admission On admission, there was swelling in glottic and subglottic region in indirect laryngoscopy and bronchoscopy with fixation of vocal cords in paramedian position. We tried to reestablish an adequate air way with bougination using Jackson esophageal bougie but there was no effect with it. So we performed vertical incision through cricoid cartilage and tracheal rings and insertion of Teflon tube in stenotic lesion for 9 months and removed it. At present time, the patient has been satisfactory corking training course.

• Korean Journal of Head & Neck Oncology
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• v.12 no.2
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• pp.201-205
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• 1996

Early detection of glottic cancer, facilitated by rigid telescopes or flexible fiberoptic laryngoscope in addition to sparse true vocal cord lymphatics, makes this a highly curable tumor in its early stage. Early glottic cancer has a high cure rate with only radiotherapy or conservative surgery. However complications such as mucositis with radiotherapy and voice complications with conservative surgery has raised recent interest in endolaryngeal laser cordectomy. Laser cordectomy can preserve phonatory function and avoid the complications such as mucositis of radiotherapy. To determine the effectiveness of laser cordectomy, the authors made a two year retrospective study of 23 early glottic cancer cases. Fourteen cases(60.9%) who underwent 1 to 3 endoscopic laser cordectomy with KTP-532 laser were cured with this procedure alone. Seven cases needed an additional radiotherapy and three cases needed therapy with salvage operation. We conclude that the endoscopic laser surgery is a good strategy for the properly selected glottic cancer.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.17 no.2
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• pp.127-132
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• 2006

Background and Objectives : Functional dysphonia is a voice disturbance in the absence of structural or neurologic laryngeal pathology characterized by voluntary misuse of laryngeal muscles. The present report reviews clinical characteristics of 25 patients with functional dysphonia. Materials and Method : We analyzed medical records, perceptual and acoustic analysis of voice samples, aerodynamic studies and laryngoscopy. Results : There was no sex or age predilection. Eighty four percent of patients presented sudden onset of symptoms and 76% had specific events at the onset. Most patients showed breathy or strained voice and various degree of vocal fold insufficiency with supraglottic compensatory contractions. Acoustic analysis revealed non-diagnostic, but mean flow rate was lower than normal in all cases. All patients responded to voice therapy except for 4 patients who were tort to follow up. Mean number of voice therapy sessions required to get responses is 1.9 sessions. Conclusion : We concluded that patients with functional dysphonia responded very well to short-term voice therapy and should be included in differential diagnosis in patients with dysphonia cannot be explained by structural or neurologic etiology.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.15 no.1
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• pp.37-42
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• 2004

Electrolarynx(EL), battery operated vibrators which are held against the neck by on-off button, has been widely used as a verbal communication method among post-laryngectomized patients. EL speech can produce easily without need of any additional surgery or special training and be used with any other methods. This institute developed a neck-typed EL named "Blueton" in commperation with EL Company Linkus, which consists of 3 parts : Vibrator part, Control part, Battery part. In this study we evaluated the acoustic characteristics of the produced voices by Blueton compared with Servox-inton using MDVP. Three EL users (2 full time users, 1 part time user) were participated. The results revelaed that NHR higher in Servox than Blueton and intensity is higher in Blueton than Servox. The spectra for vowels produced by EL speakers are mixed signals combined with talkers' vocal output and electrolarynx noise. The spectra pattern is similar with two ELs. High, SPI index and vowel spectra from MDVP demonstrated characteristics of both electrolarynxes related to noise signal. This finding suggests that Blueton helps to provide one of useful rehabilitation options in the post laryngectomy patients.