• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.271-279
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• 2007

We suggest a novel method for the evaluation of cochlear implant (CI) speech processing strategy based on neural spike train decoding. From formant trajectories of input speech and auditory nerve responses responding to the electrical pulse trains generated from a specific CI speech processing strategy, optimal linear decoding filter was obtained, and used to estimate formant trajectory of incoming speech. Performance of a specific strategy is evaluated by comparing true and estimated formant trajectories. We compared a newly-developed strategy rooted from a closer mimicking of auditory periphery using nonlinear time-varying filter, with a conventional linear-filter-based strategy. It was shown that the formant trajectories could be estimated more exactly in the case of the nonlinear time-varying strategy. The superiority was more prominent when background noise level is high, and the spectral characteristic of the background noise was close to that of speech signals. This confirms the superiority observed from other evaluation methods, such as acoustic simulation and spectral analysis.

• Journal of Audiology & Otology
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• 제24권2호
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• pp.61-70
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• 2020

Background and Objectives: To assess the academic performance, communication skills, and psychosocial development of prelingual deaf children with cochlear implants (CIs) attending mainstream schools, and to evaluate the impact of auditory speech perception on their classroom performance. Subjects and Methods: As participant, 67 children with CI attending mainstream schools were included. A survey was conducted using a structured questionnaire on academic performance in the native language, second language, mathematics, social studies, science, art, communication skills, self-esteem, and social relations. Additionally, auditory and speech performances on the last follow-up were reviewed retrospectively. Results: Most implanted children attending mainstream school appeared to have positive self-esteem and confidence, and had little difficulty in conversing in a quiet classroom. Also, half of the implanted children (38/67) scored above average in general academic achievement. However, academic achievement in the second language (English), social studies, and science were usually poorer than general academic achievement. Furthermore, half of the implanted children had difficulty in understanding the class content (30/67) or conversing with peers in a noisy classroom (32/67). These difficulties were significantly associated with poor speech perception. Conclusions: Improving the listening environment for implanted children attending mainstream schools is necessary.

• Journal of Audiology & Otology
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• 제25권4호
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• pp.217-223
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• 2021

Background and Objectives: In cochlear implant (CI) surgery, the results and causes of revision and reimplantation may guide surgeons in establishing surgical protocols for revision surgery with safe audiological outcomes. The aim of this study was to review our experience in terms of etiology, surgical strategy, and hearing outcomes in pediatric patients who underwent CI removal and reimplantation. Subjects and Methods: All patients received implants of the same brand. Pre and postoperative Categories of Auditory Performance score and aided free-field pure tone audiometry thresholds were noted. In vivo integrity tests were performed for each patient and the results of ex vivo tests of each implant were obtained from manufacturer. Results: A total of 149 CIs were placed in 121 patients aged <18 years. The revision rate in children was 6.7% (10/121 children). Six patients had a history of head injury leading to a hard failure. The causes of reimplantation in others were soft failure (n=1), electrode migration (n=1), infection (n=1), and other (n=1). All patients showed better or similar postreimplantation audiological performance compared with pre-reimplantation results. Conclusions: It is very important to provide a safe school and home environment and educate the family for reducing reimplantation due to trauma. Especially for active children, psychiatric consultation should be continued postoperatively.

• 대한청각학회지
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• 제25권4호
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• pp.217-223
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• 2021

Background and Objectives: In cochlear implant (CI) surgery, the results and causes of revision and reimplantation may guide surgeons in establishing surgical protocols for revision surgery with safe audiological outcomes. The aim of this study was to review our experience in terms of etiology, surgical strategy, and hearing outcomes in pediatric patients who underwent CI removal and reimplantation. Subjects and Methods: All patients received implants of the same brand. Pre and postoperative Categories of Auditory Performance score and aided free-field pure tone audiometry thresholds were noted. In vivo integrity tests were performed for each patient and the results of ex vivo tests of each implant were obtained from manufacturer. Results: A total of 149 CIs were placed in 121 patients aged <18 years. The revision rate in children was 6.7% (10/121 children). Six patients had a history of head injury leading to a hard failure. The causes of reimplantation in others were soft failure (n=1), electrode migration (n=1), infection (n=1), and other (n=1). All patients showed better or similar postreimplantation audiological performance compared with pre-reimplantation results. Conclusions: It is very important to provide a safe school and home environment and educate the family for reducing reimplantation due to trauma. Especially for active children, psychiatric consultation should be continued postoperatively.

• 대한청각학회지
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• 제24권2호
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• pp.61-70
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• 2020

Background and Objectives: To assess the academic performance, communication skills, and psychosocial development of prelingual deaf children with cochlear implants (CIs) attending mainstream schools, and to evaluate the impact of auditory speech perception on their classroom performance. Subjects and Methods: As participant, 67 children with CI attending mainstream schools were included. A survey was conducted using a structured questionnaire on academic performance in the native language, second language, mathematics, social studies, science, art, communication skills, self-esteem, and social relations. Additionally, auditory and speech performances on the last follow-up were reviewed retrospectively. Results: Most implanted children attending mainstream school appeared to have positive self-esteem and confidence, and had little difficulty in conversing in a quiet classroom. Also, half of the implanted children (38/67) scored above average in general academic achievement. However, academic achievement in the second language (English), social studies, and science were usually poorer than general academic achievement. Furthermore, half of the implanted children had difficulty in understanding the class content (30/67) or conversing with peers in a noisy classroom (32/67). These difficulties were significantly associated with poor speech perception. Conclusions: Improving the listening environment for implanted children attending mainstream schools is necessary.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 추계학술대회
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• pp.175-179
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• 1993

A Study on the speech processing and coding strategy for cochlear implants have been developed to create a speech signal processing system which extracts stimulus parameter including formants, pitch, amplitude information. In this study we have presented the method which extracts characteristic information of speech signal and adapt patients with hearing handicap.

• 대한방사선기술학회지:방사선기술과학
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• 제25권1호
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• pp.35-37
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• 2002

To assess the new multichannel cochlear implant by radiography in Stenver's projection, because MRI generates artifacts, inducing an electrical current and causing device magnetization. CT is relatively expensive and the metal electrodes scatter the image. Multichannel cochlear implant insertion using the multichannel cochlear implant device. Patients underwent postoperative radiography of their implants. The radiographs were obtained in a Stenver's. The insertion depth of the implant was measured on the radiographs and the results were correlated with the surgical results of insertion depth and with audiometric tests. Patients a correct inserted electrode was found, while in patient complications concerning the electrode were noticed. Radiographs in the Stenver's projection are sufficient for the postoperative assessment of the multichannel cochlear implant device and an exact evaluation of the insertion depth.

• Clinical and Experimental Otorhinolaryngology
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• 제11권4호
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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.

• 말소리와 음성과학
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• 제12권1호
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• pp.75-83
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• 2020

본 연구는 인공와우아동을 대상으로 자가음성 모니터링(self-voice monitoring)을 응용한 가창 프로그램을 시행하여 억양의 개선과 음고 산출의 변화에 미치는 영향을 알아보기 위함이다. 연구대상자는 모집된 19명의 아동 중 참여기준을 충족하고 본인 및 보호자가 자발적인 참여 의사를 표현한 7명이 최종으로 선정되었다. 연구자는 CI 집단과 비교하기 위하여 같은 연령의 건청 아동 6명을 모집하였다. 자가음성 모니터링을 응용한 가창은 노래를 녹음하여 들어보고(listen), 음성의 음고 진행방향과 숨쉬기 구간 및 음질을 확인한(explore) 다음, 목소리를 수정하여 의도한 대로 재산출하는(reproduce) 세 단계로 구성되어 있다. 데이터는 문장과 노래로 나누어 측정하였다. 문장은 발화시간과 억양 기울기 및 산출 음고의 주파수 변화, 노래는 프레이즈(phrase) 구간 내 평균 음고의 주파수의 데이터를 수집하여 선율윤곽과 산출 주파수 범위를 측정한 후 건청집단과 비교하였다. 연구 결과 문장 분석에서 인공와우 아동 집단의 사후검사 시 의문문의 문미 2음절의 억양 기울기 및 패턴이 건청 아동과 같이 상행하는 윤곽으로 변화되었으며, 노래 데이터에서는 음고의 도약 및 산출 음고의 주파수 범위가 증가하였다. 이러한 결과는 인공와우 아동을 대상으로 한 자가음성 모니터링을 응용한 가창 프로그램이 억양의 개선과 음고 산출 정확도의 효과적인 중재방안이 될 수 있으며 이를 위한 지속적인 연구가 필요하다는 것을 시사한다.

• 인간행동과 음악연구
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• 제21권1호
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• pp.29-47
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• 2024

본 연구는 인공와우이식(CI) 아동이 조성 및 템포 단서에 따라 구성된 음악에서 정서를 어떻게 지각하는지 알아보고 이를 건청(NH) 아동과 비교함으로써 CI 아동의 음악에서의 정서 지각에 대한 기초 자료를 마련하기 위해 실시되었다. 참여 대상자는 만 7세-13세 사이 CI 아동 13명과 NH 아동 36명으로 각 아동은 <장조+빠름>, <장조+느림>, <단조+빠름>, <단조+느림>의 4개 조건으로 구성된 음악을 듣고, 행복과 슬픔 중 해당 음악에서 느껴지는 정서를 선택하고 해당 정서가 어느 정도로 느껴지는지를 평정하는 과제에 참여하였다. 본 실험 전 규준 집단으로서 포함된 NH 아동이 NH 성인과 유사하게 정확한 정서 지각을 보이는지 확인하기 위한 사전 검증 절차를 진행하였으며, 두 그룹 간 유의한 차이가 없는 것으로 나타났다. 이후 CI 아동과 NH 아동의 정서 지각 수준을 비교 분석한 결과, 두 그룹 모두 <장조+빠름>의 음악을 행복의 정서로 가장 많이 지각하였으며, <단조+느림>의 음악을 가장 슬프게 지각하는 것으로 나타났다. 또한 CI 아동은 <단조+느림>을 제외한 모든 조건의 음악을 행복의 정서로 지각하는 반면, NH 아동은 장조로 구성된 음악은 행복의 정서를, 단조로 구성된 음악은 슬픔의 정서로 지각하는 것으로 나타났다. 본 연구 결과를 통해 CI 아동이 정서를 지각하는 데 있어 조성 단서보다는 템포 단서에 의존하는 경향이 있음을 확인하였으며, CI 아동의 음악에서의 정서 지각 과정을 보다 다각적으로 이해할 수 있도록 하는 기초 자료를 제시했다는 데 그 의의가 있다.