• 대한임상검사과학회지
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• 제44권3호
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• pp.128-135
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• 2012

The kidney and cochlea have similar physiological characteristics, specifically the active transport of fluid and electrolytes, similar effects of aminoglycosides and some immunological factors. Several mitochondrial DNA (mtDNA) defects have been identified to be associated with hearing impairment either in syndromic or nonsyndromic forms. Dialysis patients had more oxidative stress than healthy subjects and this elevated oxidative stress leads to alterations of the mtDNA. To generate a more comprehensive analysis of the relationship between mitochondrial variation and hearing loss, two SNPs of 10609, 14668 position showed nominal levels of association with hearing loss. In our result, the mean PTA values in the ESRD patients were $28{\pm}13.9\;(mean{\pm}SD)dB$ and $51.0{\pm}23.2dB$ in low and high frequencies, which were significantly higher than those in the normal controls. 10609T>C and 14668C>T were significantly associated with hearing loss in the ESRD patients. In summary, our results suggest that the polymorphisms of the ND4L subunit gene might be association with ESRD patients and hearing loss.

• Reproductive and Developmental Biology
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• 제34권2호
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• pp.63-71
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• 2010

The spontaneous mutant circling mouse (cir/cir) shows a circling behavior and hearing loss. We produced transgenic mice overexpressing transmembrane inner ear (tmie) gene, the causative gene, for the phenotypic rescue of the circling mouse. Through the continuous breeding with circling mice, the cir/cir homozygous mice carrying the transgene (cir/cir-tg) were produced. The rescued cir/cir-tg mice were able to swim in the water with proper orientation and did not show any circling behavior like wild type mice. Western blot and immunohistochemical analysis exhibited that the transgenic tmie was expressed in the inner ear. Inner and outer hair cells were recovered in the cochlea and spiral ganglion neurons were also recovered in the rescued mice. Auditory brainstem response (ABR) test demonstrated that the cir/cir-tg mice are able to respond to sound. This study demonstrates that tmie transgene can recover the hearing impairment and abnormal behavior in the circling mouse.

• Applied Microscopy
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• 제44권1호
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• pp.8-14
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• 2014

The auditory system of the Korean greater horseshoe bat (Rhinolophus ferrumequinum korai, RFK) is adapted to its own echolocation signal, which consist of constant frequency (CF) element and frequency modulated (FM) element. In contrast, the Japanese long-fingered bat (Miniopterus schreibersii fuliginosus, MSF) emits FM signals. In the present study, the characteristics of stereocilia in RFK (a CF/FM bat) and MSF (a FM bat) were studied in the apical turn of the cochlea where the lower frequencies are transduced. Stereocilia lengths and numbers were quantitatively measured in RFK by scanning electron microscopy and compared with those of MSF. Each inner hair cells (IHCs) of RFK possessed three rows of stereocilia, whereas MSF possessed five rows of stereocilia. Gradients in stereocilia lengths and numbers of stereocilia of the IHCs of RFK were found to be less pronounced and fewer, respectively, than those of MSF. Each outer hair cells (OHCs) possessed three rows of stereocilia in both species. OHCs stereocilia in RFK that distinguished it from MSF were a shorter length and a greater number of stereocilia. These features suggest that the apical cochleas of RFK are adapted for the processing of higher frequency echolocation calls rather than that of MSF.

• 재활복지공학회논문지
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• 제8권1호
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• pp.9-17
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• 2014

전기 자극 청신경 복합활동전위(electrical compound action potential; ECAP)는 인공와우로 청신경을 자극하고 동시에 반응을 기록한다. 이 연구는 인공와우에서 ECAP의 효용성을 높이기 위하여 자극과 기록에 대하여 연구하고자 한다. 대상은 문헌 또는 사례 연구를 제외한 연구 논문 34 편으로 하였다. 연구는 펄스 및 자극 조건, 잡파 억제 및 기록 조건 등을 분석하였다. 효과적인 신경 발화, 안정적인 역치 확인, 신경 퇴행 방지 등을 위해서는 펄스폭과 위상 간격이 가급적 짧고, (-)위상이 앞선 양위상 펄스를 사용하였다. 자극은 펄스 간격, 자극비율, 자극 방식 등을 정하여 와우의 첨부, 중간, 기저회전으로 C-level 정도로 하였다. 잡파는 전방차폐법, 거푸집소거법으로 제거하였고, 분명한 파형을 획득하기 위해서는 전극 간격, 증폭 정도, 평균 가산 회수 등의 추가 조절이 필요하다.

• ETRI Journal
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• 제35권4호
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• pp.697-705
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• 2013

Emerging trends in the area of digital very large scale integration (VLSI) signal processing can lead to a reduction in the cost of the cochlear implant. Digital signal processing algorithms are repetitively used in speech processors for filtering and encoding operations. The critical paths in these algorithms limit the performance of the speech processors. These algorithms must be transformed to accommodate processors designed to be high speed and have less area and low power. This can be realized by basing the design of the auditory filter banks for the processors on digital VLSI signal processing concepts. By applying a folding algorithm to the second-order digital gammatone filter (GTF), the number of multipliers is reduced from five to one and the number of adders is reduced from three to one, without changing the characteristics of the filter. Folded second-order filter sections are cascaded with three similar structures to realize the eighth-order digital GTF whose response is a close match to the human cochlea response. The silicon area is reduced from twenty to four multipliers and from twelve to four adders by using the folding architecture.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• 제61권12호
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• pp.705-709
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• 2018

It is challenging to achieve sufficient hearing gain in patients with mixed hearing loss. In chronic middle ear diseases, conventional passive reconstructive surgeries often result in suboptimal hearing gain and additional hearing aids may have limitations due to insufficient sound amplification, occlusion effect, acoustic feedback, and skin irritation. Middle ear implantation (MEI) using Vibrant Soundbridge (VSB) is another option for auditory rehabilitation in mixed hearing loss as well as sensorineural hearing loss. The floating mass transducer of VSB can be placed on various middle ear structures either directly or using different types of couplers in order to deliver vibratory mechanical energy to the cochlea. We report a patient who presented with bilateral mixed hearing loss due to chronic otitis media and had limitations using conventional hearing aids in the worse hearing ear. The patient was successfully treated with MEI using the Bell coupler together with middle ear surgery in a single step.

• 한국멀티미디어학회논문지
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• 제22권8호
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• pp.923-929
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• 2019

In this paper, biomimetic based physical ear model proposed for measuring the characteristics of a hybrid-acoustic sensor for fully implantable middle-ear hearing aid. The proposed physical ear model consists of the external ear, middle-ear, and cochlea. The physical ear model was implemented based on the anatomical structure and CT images of the human ear. To confirm the characteristics of the ear model, the vibrational characteristics of the stapes was measured after applying sound pressure to the tympanic membrane. The measured results were compared with the vibrational characteristics of the human temporal bone specified by ASTM F2504-05. Through the comparison results, the feasibility of the proposed ear model was confirmed. Then, after attaching the hybrid-acoustic sensor to the ear model, the output characteristics of the ECM and acceleration sensor were measured according to the sound pressure. The measured results were compared with previous studies using human temporal bone, and the usefulness of the proposed physical ear model was verified through the analysis results.

• Journal of Audiology & Otology
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• 제23권2호
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• pp.89-95
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• 2019

Background and Objectives: Knowing the ototoxic potential of the agents used in medical treatments is important for the protection of hearing. Although we have knowledge regarding some effects of dexmedetomidine, which is an anesthetic-sparing drug, its influence over the hearing system has never been studied and is obscure yet. The aim of this study is to determine the effects of intravenous dexmedetomidine application during sevoflurane anesthesia on otoacoustic emissions (OAEs). Subjects and Methods: This prospective randomized study was performed on 60 patients (34 male, 26 female, mean age: 30.6±9.2 years) who were scheduled for an elective surgery under general anesthesia and the patients were enrolled and randomly divided into 2 groups. They received dexmedetomidine (Group D) or Saline (Group S) infusion during a standardized Sevoflurane anesthesia. Transient and distortion product OAEs were measured preoperatively and postoperatively (24th hour). OAE results were compared within and between groups. Results: In group D postoperative OAEs were lower than preoperative OAEs and postoperative levels of group S, especially at low frequencies (p<0.05). Conclusions: Dexmedetomidine infusion affects the micromechanical function of cochlea especially in the low-frequency region. Dexmedetomidine should be carefully used during general anesthesia to avoid its probable harmful effects on cochlear micromechanics.

• 대한청각학회지
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• 제23권2호
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• pp.89-95
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• 2019

Background and Objectives: Knowing the ototoxic potential of the agents used in medical treatments is important for the protection of hearing. Although we have knowledge regarding some effects of dexmedetomidine, which is an anesthetic-sparing drug, its influence over the hearing system has never been studied and is obscure yet. The aim of this study is to determine the effects of intravenous dexmedetomidine application during sevoflurane anesthesia on otoacoustic emissions (OAEs). Subjects and Methods: This prospective randomized study was performed on 60 patients (34 male, 26 female, mean age: 30.6±9.2 years) who were scheduled for an elective surgery under general anesthesia and the patients were enrolled and randomly divided into 2 groups. They received dexmedetomidine (Group D) or Saline (Group S) infusion during a standardized Sevoflurane anesthesia. Transient and distortion product OAEs were measured preoperatively and postoperatively (24th hour). OAE results were compared within and between groups. Results: In group D postoperative OAEs were lower than preoperative OAEs and postoperative levels of group S, especially at low frequencies (p<0.05). Conclusions: Dexmedetomidine infusion affects the micromechanical function of cochlea especially in the low-frequency region. Dexmedetomidine should be carefully used during general anesthesia to avoid its probable harmful effects on cochlear micromechanics.

• 재활복지공학회논문지
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• 제11권1호
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• pp.63-71
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• 2017

본 논문에서는 달팽이관의 정원창 이식용으로 최근 새롭게 제안된 3코일 벨로우즈형 진동체(tri-coil bellows transducer, TCBT)를 이용하는 반이식형 인공중이(semi-implantable middle ear hearing device)를 위한 신호처리회로를 설계하였다. 설계된 반이식형 인공중이는 높은 효율을 가지는 유도결합 방법을 이용하여 귀 뒤편에 착용되는 체외기와 대응되는 피부 내측에 위치하는 체내기 간에 데이터를 전송한다. 귀 뒤 부위의 피부두께를 포함하는 반이식형 인공중이의 송수신 거리를 고려하여 송수신 코일과 신호처리 회로를 설계 및 구현하였다. 또한 데이터 전송 효율을 높이기 위하여, 전력을 충분히 증폭하기 위한 체외기의 출력부도 설계 하였다. 유도결합 방식을 이용한 반이식형 인공중이의 동작을 확인하기 위하여, PSpice를 이용하여 회로해석을 수행하였으며, 활용 가능한 크기의 신호처리 보드를 제작하여 그 성능을 검증하였다.