• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7C
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• pp.413-420
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• 2011

This paper proposes a new adaptive algorithm to cancel the acoustic feedback and noise signals in the binaural hearing aids. The convergence performances of the proposed algorithm are improved by updating coefficients of the feedback canceller after the speech signal is cancelled from the residual signal with dual microphones. The feedback canceller firstly cancels the feedback signal from the microphone signal, and then the noise canceller reduces the noise by the beamforming method. To assure that binaural hearing aids converge stably, the left-sided hearing aid only is converged firstly, next the right-sided hearing aid only is converged. To verify performances of the proposed algorithm, simulations were carried out for a speech. As the results of simulations, it was proved that we can advance 14.43dB SFR(Signal to Feedback Ratio) on the average for the feedback canceller, 10.19dB SNR(Signal to Noise Ratio) improvement on the average for the noise canceller, in case that this algorithm is used.

• Clinical and Experimental Otorhinolaryngology
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• v.11 no.4
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• pp.250-258
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• 2018

Objectives. To compare narrative skills between fourth and fifth grades of Persian-speaking students with hearing impairments and typical hearing students of the same grade and also to evaluate the effects of group, sex, hearing age, and educational grade of the students on their spoken/written narrative performance. Methods. The subjects were 174 students aged 10-13 years, 54 of whom wore cochlear implants, 60 suffered from moderate to severe hearing losses and wore hearing aids, with the remaining 60 students being typical hearing in terms of the sense of hearing. The micro- and macrostructure components of spoken and written narrative were elicited from a pictorial story (The Playful Little Elephant) and then scored by raters. Results. Compared to the typical hearing, the students with hearing impairments had significantly lower scores in all of the microstructure components of narratives. However, the findings showed no significant difference among different groups in macrostructure components of narratives. It was also revealed that the students had equal performance in spoken and written narrative. Finally, factor analysis manifested that group, sex, hearing age, and educational level of children might alter the outcome measures in various interactions. Conclusion. Although cochlear implantation was more effective than hearing aid on spoken and written narrative skills, the Persian-speaking students with hearing impairments were seen to need additional trainings on microstructure components of spoken/written narrative.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1744-1749
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• 2013

Acoustic feedback is perceived as whistling or howling, which is a major complaint of hearing-aids users. Acoustic feedback cancellation is important in hearing-aids because acoustic feedback degrades performance of the hearing aid device by reducing maximum insertion gain. Adaptive systems for estimate acoustic feedback path and feedback suppression algorithms have been proposed in order to solve this problem. A typical feedback cancellation algorithm is LMS(least mean squares) because of its computational efficiency. However it has problem of convergence performance in high correlated input signal. In this paper, we propose a new variable step-size normalized LMS(least mean squares) algorithm using VAD(voice activity detection) to overcome the limitation of the LMS algorithm. The VAD algorithm is GSAP(global speech absence probability) and the feedback cancellation algorithm is normalized LMS. The proposed algorithm applies different step-size between voice and non-voice using VAD, for high stability, fast convergence speed and low misalignment when correlated inputs, such as speech. The result of simulation with white noise mixed speech signal, the proposed algorithm shows high performance then traditional algorithm in terms of stability, convergence speed and misalignment.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.19 no.1
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• pp.21-27
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• 2008

Total laryngectomy is the most useful procedure tor advanced laryngopharyngeal cancer, but it remains the major problem such as loss of voice. Voice restoration is essential for every patients who undergo a total laryngectomy. Ideal voice rehabilitation methods can resolve three factors. First, every laryngectomee can produce voice sufficient for communication, second every patient should be allowed to use both hands freely during phonation, and last, the voice restoration methods should be easy and safe without complication during and after treatment. Among various voice rehabilitation procedures during or after total laryngectomy, it can be divided electronic and pneumatic methods. In pneumatic methods, there are also divided both pulmonary air and non-pulmonary air methods. The non-pulmonary air methods include esophageal speech, buccal speech, and pharyngeal speech. Pulmonary air methods are divided into surgical and non-surgical such as pneumatic speech aid. In the surgical methods, there are neoglottic operation, tracheopharyngeal shunt, and tracheopharyngeal shunt operations. Recently, tracheoesophageal shunt with or without prosthesis are being recognized the most effective method. Blom-Singer low pressure prosthesis, Panje button, and Provox are well known types of prosthesis in the tracheoesophageal shunt operation. Amatsu method is a kind of famous tracheoesophageal shunt method without using prosthesis. Authors tried to review the published articles for evaluation of effectiveness and problems of tracheoesophageal shunt operation with or without prosthesis. In conclusion, indwelling type of prosthesis and pharyngeal myotomy and plexus neurectomy are recommended for higher success rate during tracheoesophageal puncture procedure. More over, Amatsu method is also one of the recommended voice rehabilitation procedure during total laryngectomy. In this situation, pharyngeal myotomy and plexus neurectomy may be helpful for better fluent communication.

• 재활복지
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• v.18 no.4
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• pp.295-314
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• 2014

The purpose of this study was to supply the baseline data for auditory rehabilitation in the field through error type and rate of the phoneme which the hearing impaired feel difficulty to discriminate. Thirty participants with sensorineural hearing loss heard KCPT lists through recorded voice by male and female to get the data about error type and KCPT score accordance with talker's gender. In the initial consonant test list, /ㄷ/, /ㅂ/, /ㅃ/, /ㅉ/, /ㅌ/ showed more than 30% error rate while /ㄱ/and /ㄷ/ showed in final consonant test list. The most common error type was the initial consonant substitution or the final consonant substitution for the initial or final consonant test lists. Talker's gender effect was not signigicant showing no statistical difference between the scores when compared results from male voice and female voice. It means that KCPT can be used regardless of talker's gender in clinics.

• Journal of Biomedical Engineering Research
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• v.31 no.1
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• pp.20-26
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• 2010

The aim of this study was to test the feasibility of a wireless transceiver that can be inserted into the ear canal. The wireless technology could minimize the cosmetic problems of patients, and it can be applied to binaural hearing aids for improving speech perception. In order to implement the ear canal insertable transceiver, simple finite-difference time-domain (FDTD) simulations were carried out to determine the feasibility, and the hardware of the transceiver was implemented within the ear shell. The size of the implemented transceiver was only $7{\times}7mm$, and it could successfully transmit signals to external devices. In order to measure the radiation pattern, a simple RF phantom was used, and the maximum attenuation from the phantom was observed to be 23 dB when the reference antenna was placed at a distance of 2 m from the transmitter.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.5 no.1
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• pp.41-46
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• 2011

A sensorineural hearing loss(SNHL) occurs when the cochlea in the inner has functional problem. The region in the cochlea with no(or very few) functioning inner hair cells or neurons called 'dead regions'. Amplification using hearing aid over a frequency range corresponding to a dead region may not a beneficial. In this paper, we compared speech recognition with different location of dead region and gain and searched effective gain for hearing aid with dead region. In order to experiment, eight people who has normal hearing ware tested, and we used white noise and babble noise(SNR=0 dB). we divided by three conditions, low, mid and high frequency dead region. In addition, the gains in dead region ware 14.5 dB, 11.5dB and 6 dB gain. There ware different results by location of dead region. The result of WRS and preference in mid-frequency dead region and high-frequency dead region ware higher than them in low-frequency dead region. When we compared as gains, the score of WRS with lower gain was higher than 14.5 dB gain, and the preference was lower as higher gain.

• Clinical and Experimental Pediatrics
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• v.50 no.1
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• pp.7-13
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• 2007

Hearing loss in newborns is the most frequently occurring birth defect. If hearing impaired children are not identified and managed early, it is difficult for many of them to acquire the fundamental language, social and cognitive skills that provide the foundation for later schooling and success in society. All newborns, both high and low risk, should be screened for hearing loss in the birth hospital prior discharge (Universal Newborn Heaing Screening, UNHS). Objective physiologic measures must be used to detect newborns and very young infants with hearing loss. Recent technological developments have produced screening methods and both evoked otoacoustic emission (EOAE) and auditory brainstem response (ABR) have been successfully implemented for UNHS. Audiologic evaluation should be carried out before 3 months of age and infants with confirmed hearing loss should receive intervention before 6 months of age. All infants who pass newborn hearing screening but who have risk indicators for other auditory disorders and/or speech and language delay receive ongoing audiologic surveillance and monitoring for communication development. Infants with sensorineural hearing loss are managed with hearing aids and receive auditory and speech-language rehabilitation therapies. Cochlear implants can be an outstanding option for certain children aged 12 months and older with severe to profound hearing loss who show limited benefit from conventional amplifications.

• Phonetics and Speech Sciences
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• v.1 no.4
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• pp.177-185
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• 2009

This study investigates the differences in mean F0, intensity, jitter and shimmer across hearing aid, gender and vowels. For this study, 20 hearing-impaired adults and 20 normal hearing adults as a control group were asked to read 7 Korean vowels(/$\alpha$, $\Lambda$, o, u, ɯ, i, $\varepsilon$/). Subjects' readings were recorded by NasalView and analyzed by Praat. Results showed that the means of F0 were significantly higher in the hearing impaired group(HL) than in the normal hearing group(NH), in the female group than in male group, and in high vowels than in low vowels. Second, intensity was significantly higher in the normal hearing group(NH) than in the hearing impaired group(HL), in male group than in female group, and in low vowels than in high vowels. Third, jitter was significantly higher in the normal hearing group(NH) than in the hearing impaired group(HL), and in female group than in male group and in the back vowels than in front vowels. Finally, shimmer was significantly higher in the normal hearing group(NH) than in the hearing impaired group(HL), and in male group than in female group. In particular, the male group showed that front vowels tend to have higher shimmer than back vowels.

• Phonetics and Speech Sciences
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• v.2 no.1
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• pp.135-145
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• 2010

This study investigates the differences in mean F0, intensity, jitter, and shimmer across hearing aid, gender, and vowels. For this study, 18 hearing-impaired children, 18 cochlear implanted children, and 18 normal hearing children as a control group were asked to read seven Korean vowels (/$\alpha$, $\wedge$, o, u, w, i, $\varepsilon$/). Subjects' readings were recorded by NasalView and analyzed by Praat. Results showed that the means of F0 were significantly higher in the hearing impaired group than in the normal hearing group; in the female group than in the male group; and in high vowels than in low vowels. Second, intensity was significantly higher in the hearing impaired group than in the normal hearing group; in the female group than in the male group; and in low vowels than in high vowels. Third, jitter was significantly higher in the normal hearing group than in the hearing impaired group; in the female group than in the male group; and in back vowels than in front vowels. Finally, shimmer was significantly higher in the CI group than in the normal hearing group or the hearing aided group; in the male group than in the female group; and in low vowels than in high vowels.