• Journal of Biomedical Engineering Research
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• v.10 no.2
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• pp.112-113
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• 1989

Two-Dimensional modelling of the Cochlear biomechanics is presented in this paper. The Laplace partial differential equation which represents the fluid mechanics of the Cochlea has been transformed into two-dimensional electrical transmission line. The procedure of this transformation is explained in detail. The comparison between one and two dimensional models is also presented. This electrical modelling of the basilar membrane (BM) is clearly useful for the next approach to the further. Development of active elements which are essential in the producing of the sharp tuning of the BM. This paper shows that two-dimension model is qualitatively better than one-dimensional model both in amplitude and phase responses of the BM displacement. The present model is only for frequency response. However because the model is electrical, the two-dimensional transmission line model can be extended to time response without any difficult.

• Journal of Biomedical Engineering Research
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• v.10 no.2
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• pp.97-101
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• 1989

N1 and N2 gross neural action potentials were measured from the round window of the guinea pig cochlea at the onset of the acoustic stimuli. N1-N2 audiograms were made by means of regulating stimulant intensities in order to produce constant N1-N2 potentials as criteria for different input tone pip frequencies. The lowest threshold was measured with an input tone pip I5 dB SPL in intensity and 12 KHz in frequency when the animal was in normal physiological condition. The procedure of experimental measurements is explained in detail. This experimental approach is very useful for the investigation of the Cochlear function. Both noN1inear and active functions of the Cochlea can be monitored by N1-N2 audiograms.

• Phonetics and Speech Sciences
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• v.3 no.3
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• pp.157-165
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• 2011

This study investigated speech rate and intonation slope (least square method; F0, quarter-tone) in normal and CI children's utterances. Each group consisted of 12 people and were divided into groups of children with CI operation (before 3;00), children with CI operation (after 3;00), and normal children. Materials are composed of four kinds of grammatical dialogue sentences which are lacking in respect. Given three groups as independent variables and both speech rate and intonation slope as dependent variables, a one-way ANOVA showed that normal children had faster speech rates and steeper intonation slopes than those of the CI group. More specifically, there was a statistically significant speech rate difference between normal and CI children in all of the sentential patterns but imperative form (p<.01). Additionally, F0 and qtone slope observed in sentential final word showed a significant statistical difference between normal and CI children in imperative form (f0: p<.01; q-tone: p<.05).

• Proceedings of the KOR-BRONCHOESO Conference
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• 1987.05a
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• pp.7.2-7
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• 1987

Waver 와 Bray (1930) 가 cochlear microphonic을 처음 발견한 이래 Derbyshire 와 Davis (1935)는 summating potential을 각각 처음 기술하여 이 세가지 전위를 electrocochleogram 이라 칭하였고 이는 감음신경성 난청의 감별진단 및 청각생리연구에 이용되어 왔다. 저자들은 정상 guinea pig 10 마리를 대상으로 DANAC 7E ERA청각계기를 사용하여 정원창에서 action potential과 summating potential을 측정하였으며 주파수에 따른 역치 자극간 간격 및 두 potential의 상호관계를 분석하여 다음과 같은 결과를 얻었다. 1) 주파수가 증가함에 따라 그 역치는 점차 감소하였다. 2) 자극음의 강도와 action potential의 $N_1$ component 진폭은 상호 비례관계를 보여 주었으며 주파수 증가에 따라 $N_1$ component 진폭은 점차 증가하였다. 3) Action potential 의 $N_1$ component latency는 주파수가 증가할수록 역비례 관계를 보여 주었다. 4) N$_1$ component의 진폭과 자극간 간격(interstimulus interval, ISI)과의 관계는 ISI가 80~160m sec사이에서 plateau를 형성하였다. 5) summating potential은 자극음의 강도가 증가함에 따라 그 진폭이 증가하였으며 action potential도 증가하였으나, SP/AP는 감소하는 경향을 보였다.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.3142-3144
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• 2000

청각시스템의 저전력 및 가격의 저렴화를 위해 달팽이관의 BM(Basilar Membrain)모델을 아날로그 VLSI 마이크로 파워 공정으로 구현하고 있다. Lyon and Mead는 실리론 공정으로 달팽이관 모델을 효과적으로 구현하였다. 이는 단순 직렬 연결된 구조로 각 채널의 지연시간의 차이로 인해 인식율이 떨어질 수 있다. 본 논문에서는 소리의 주파수 정보 추출기능을 하는 직렬 연결된 트리구조(TSBF:Tree-structured Cascaded Bandpass Filter)의 16채널의 아날로그 중간대역통과 필터회로를 CMOS VLSI 공정을 이용하여 설계하였다. 직렬 연결된 저대역통과필터와 고대역통과필터로 각 채널의 중간대역통과 필터를 구현하였다. 이러한 구조에서는 각 채널의 지연시간이 동일하므로 인식율을 높일 수 있다. 그리고 고대역통과필터를 1-poly 디지털 공정으로 구현 가능하고 기생 캐패시터의 영향을 적게 받는 구조로 설계하였다.

• Journal of Biomedical Engineering Research
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• v.16 no.1
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• pp.77-84
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• 1995

Nl and N2 gross neural action potentials were measured from the round window of the guinea pig cochlea at the onset of the acoustic stimuli. Nl -N2 audiograms were made by means of regulating stimulant intensities in order to produce constant Nl -N2 potentials as criteria for different input tone pip frequencies. The lowest threshold was measured with an input tone pip 15 dB SPL in intensity and 12 KHz in frequency when the animal was in normal physiological condition. The procedure of experimental measurements is explained in detail. This experimental approach is very useful for the investigation of the Cochlear function. Both nonlinear and active functions of the Cochlea can be monitored by Nl -N2 audiograms. Key words : Guinea Pig, Cochlea, Wl and N2 Gross Neural Action Potential, Nl -N2 audiogram.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2613-2615
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• 2001

청각시스템의 저전력 및 가격의 저렴화를 위해 달팽이관의 BM(Basilar Membrain)모델을 아날로그 VLSI 마이크로 파워 공정으로 구현하고 있다. 본 논문에서는 소리의 주파수 정보 추출기능을 하는 직렬 연결된 트리구조(TSBF : Tree-structured Cascaded Bandpass Filter)의 16채널의 아날로그 중간대역통과 필터회로를 CMOS VLSI 공정을 이용하여 설계하였다. 특히 큰 입력 신호에 대해서도 파형왜곡 없이 선형적인 특성을 가지는 트랜스 컨턱터를 이용하여 필터를 구현하였다. 필터는 저대역통과필터와 출력이득의 감쇄를 줄이기 위해서 중간대역통과필터를 이용하여 전체 시스템을 설계했다. 본 논문에서 기존의 150mVp-p 입력신호 범위의 트랜스 컨턱터를 Substrate 입력을 가지는 트랜스 컨턱터를 이용하여 입력신호 범위를 1Vp-p 까지 늘였다.

• Journal of Biomedical Engineering Research
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• v.40 no.3
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• pp.75-80
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• 2019

Listening effort represents the listener's attention, stress, required cognition resource, and mental exertion to understand a speech in various situations. Recently, it has been focused to evaluate an effectiveness of hearing aids and cochlear implant. The physiologic measures, such as heart rate, skin conductance, electroencephalography, and pupil dilation, have been used to objectively measure listening effort. In this study, we investigated the feasibility of temporal and spectral heart rate variabilities to measure listening effort to understand speech in the presence of background noise. The results showed that several heart rate variabilities significantly increased as increasing background noise level. Finally, the heart rate variability can be used as an objective tool to measure listening efforts.

• Korean Journal of Audiology
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• v.25 no.4
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• pp.235-240
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• 2021

Sudden sensorineural hearing loss (SSNHL) is a common disorder; however, sequential, bilateral presentation of the disease is rarer than unilateral presentation. Clinical otologists usually focus on treating the side with impaired hearing when patients first present with unilateral SSNHL, and therefore, may not warn patients of the possibility of subsequent hearing impairment in the contralateral ear. Furthermore, it is professionally discouraging when a patient presents with profound, sequential SSNHL after initial treatment. This may adversely impact the doctor-patient relationship, even if the patient is offered the best possible care from their first visit. Herein, we report the case of a patient with profound, idiopathic, bilateral SSNHL with a time interval of 37 days between involvement of both ears. Even though high-dose steroids were administered intraorally and intratympanically, the patient's hearing was not restored, and the patient eventually required bilateral cochlear implant surgery. Our report demonstrates that sequential, profound, bilateral SSNHL may manifest without any specific signs.

• Journal of Audiology & Otology
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• v.25 no.4
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• pp.235-240
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• 2021

Sudden sensorineural hearing loss (SSNHL) is a common disorder; however, sequential, bilateral presentation of the disease is rarer than unilateral presentation. Clinical otologists usually focus on treating the side with impaired hearing when patients first present with unilateral SSNHL, and therefore, may not warn patients of the possibility of subsequent hearing impairment in the contralateral ear. Furthermore, it is professionally discouraging when a patient presents with profound, sequential SSNHL after initial treatment. This may adversely impact the doctor-patient relationship, even if the patient is offered the best possible care from their first visit. Herein, we report the case of a patient with profound, idiopathic, bilateral SSNHL with a time interval of 37 days between involvement of both ears. Even though high-dose steroids were administered intraorally and intratympanically, the patient's hearing was not restored, and the patient eventually required bilateral cochlear implant surgery. Our report demonstrates that sequential, profound, bilateral SSNHL may manifest without any specific signs.