• 대한음성학회지:말소리
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• 제62호
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• pp.33-49
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• 2007

The purpose of this study is 1) to investigate the phoneme inventories and phonological processes of cochlear implant(CI) children and 2) to describe their utterances using narrow phonetic transcription method. All ten subjects had more than 2 year-experience with CI and showed more than 85 % open-set sentence perception abilities. Average consonant accuracy was 81.36 % and it was improved up to 87.41% when distortion errors were not counted. They showed similar phonological processing patterns to HA or normal hearing children in some way as well as different phonological processing patterns from HA or normal hearing children. The prominent distortion error pattern was weakening of consonants. Every subject had his/her idiosyncratic error pattern that demanded his/her own individualized therapy program.

• 말소리와 음성과학
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• 제1권4호
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• pp.203-207
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• 2009

Electrically evoked compound action potentials (ECAP) have originated from the distal end of the auditory nerve. ECAP are characterized as the difference between the clearly large trough (N) and the following positive peak (P). N-wave occurs around $200-400\;{\mu}s$ after stimulus onset and P-wave at around $400-800\;{\mu}s$. Contrary to expectations, positive peaked ECAP (pp-ECAP) was dominated by a relatively large-amplitude positive following negative peak. pp-ECAP can be recorded from the sites on or near the surgically exposed nerve trunk in animal models and/or in cases of monophasic stimulation. This study will provide the causes of the appearance of pp-ECAP in cases of cochlear implant recipients using imaging studies and medical records and statistically analysis between N-P and P-N on the amplitude input-output function (amp-I/O) for the prediction of the possibilities of clinical tools. Thirteen children participated in the study and received a Cochlear CI-24RE (CA). ECAP was recorded using auto-NRT (Cochlear Ltd., Australia) at four to five weeks post surgery. pp-ECAP was measured from 36 electrodes and typical ECAP from 220 electrodes. There was no abnormality in the imaging study and operation finding in patients with typical ECAP. pp-ECAP was found at the inner ear anormaly and ossification in imaging study and gel-state inner ear fluid was observed in the operation finding. The amplitude of pp-ECAP increased depending on current intensities, but amp-I/O increase more gradually than in the case of typical ECAP (p=0.003). pp-ECAP is antidromic potential which can record from the inner ear anormaly and ossified cochlear. Amp-I/O also depends on current intensity as well typical ECAP. These results provide a useful tool for audiological evaluation for the spiral ganglion cell status to the value of pp-ECAP.

• 재활복지공학회논문지
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• 제8권3호
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• pp.227-232
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• 2014

이 연구는 언어습득 이후 난청 성인의 인공와우 이식 후 음소 지각과 음소 지각에 오류 양상 등을 알아보고자 한다. 일측 인공와우를 1년 이상 사용한 23 세부터 79($49{\pm}14$) 세 사이의 21 명(m:f=13:8)의 자음 지각 검사를 이용하였다. 자음 지각 성적은 11~86 ($60{\pm}17$)%로 관찰되었고, 인공와우 교정청력(p< .046)을 제외한 술 전 청력, 난청 기간, 인공와우 이식 연령, 술 후 사용기간 등은 유의한 관계가 나타나지 않았다. 이는 언어발달이 정상적인 경우 다른 요인들 보다는 청력의 개선을 통한 청각적 자극이 자음지각에 가장 중요하다는 것을 시사한다. 음소 정답률은 마찰음(/ㅅ, ㅆ, ㅎ/)과 파찰음(/ㅈ, ㅉ, ㅊ/)이 71~92 ($79{\pm}7$)%로 파열음(/ㅂ, ㅃ, ㅍ, ㄷ, ㄸ, ㅌ, ㄱ, ㄲ, ㅋ/)과 유음(/ㄹ/) 및 비음(/ㅁ, ㄴ/)의 33~80 ($50{\pm}13$)%보다 높게 관찰되었다. 오류 양상은 조음 방법이 같은 음소들을 서로 혼동하는 경향을 보였으며, 이는 주파수의 미세한 변화나 강도의 시간적 변화를 변별하지 못한 것으로 보인다.

• 대한청각학회지
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• 제25권1호
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• pp.1-7
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• 2021

The scope of teleaudiology has been noted with telehealth due to Coronavirus disease (COVID-19) recently. As the notion has been around us for more than 20 years ever since 1999, it is necessary to perceive the knowledge accurately and prepare for the successful implementation of it. Therefore, the literature review including screening and diagnostic audiometry, cochlear implants and hearing aids, and aural rehabilitation, telecommunications technology regarding several fields of teleaudiology, and considerations for practicing were identified. Although overall internet-based audiological services showed benefits in terms of outcome and accessibility, uncertainties of cost-effectiveness, the optimal level of support, and a need for further studies of many aspects for teleaudiology has arisen. In the view of technology, the store-and-forward (asynchronous/hybrid) and a real-time (synchronous) methods were introduced with one applied and nine registered patents recorded from 2004 to 2020 for the invention of teleaudiology in the United States. Also, 10 checklists were suggested for planning teleaudiology practice from prior experience in hosting the teleaudiology program. Conclusively, it is hoped that this review sheds light on recognizing and improving the existing teleaudiology services and helps overcome the challenges faced in the era of pandemic and untact world to come.

• Journal of Audiology & Otology
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• 제25권1호
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• pp.1-7
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• 2021

The scope of teleaudiology has been noted with telehealth due to Coronavirus disease (COVID-19) recently. As the notion has been around us for more than 20 years ever since 1999, it is necessary to perceive the knowledge accurately and prepare for the successful implementation of it. Therefore, the literature review including screening and diagnostic audiometry, cochlear implants and hearing aids, and aural rehabilitation, telecommunications technology regarding several fields of teleaudiology, and considerations for practicing were identified. Although overall internet-based audiological services showed benefits in terms of outcome and accessibility, uncertainties of cost-effectiveness, the optimal level of support, and a need for further studies of many aspects for teleaudiology has arisen. In the view of technology, the store-and-forward (asynchronous/hybrid) and a real-time (synchronous) methods were introduced with one applied and nine registered patents recorded from 2004 to 2020 for the invention of teleaudiology in the United States. Also, 10 checklists were suggested for planning teleaudiology practice from prior experience in hosting the teleaudiology program. Conclusively, it is hoped that this review sheds light on recognizing and improving the existing teleaudiology services and helps overcome the challenges faced in the era of pandemic and untact world to come.

• 대한의용생체공학회:의공학회지
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• 제31권6호
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• pp.417-426
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• 2010

We present a speech processing strategy incorporating instantaneous frequency (IF) encoding for the enhancement of melody recognition performance of cochlear implants. For the IF extraction from incoming sound, we propose the use of a Teager energy operator (TEO), which is advantageous for its lower computational load. From time-frequency analysis, we verified that the TEO-based method provides proper IF encoding of input sound, which is crucial for melody recognition. Similar benefit could be obtained also from the use of a Hilbert transform (HT), but much higher computational cost was required. The melody recognition performance of the proposed speech processing strategy was compared with those of a conventional strategy using envelope extraction, and the HT-based IF encoding. Hearing tests on normal subjects were performed using acoustic simulation and a musical contour identification task. Insignificant difference in melody recognition performance was observed between the TEO-based and HT-based IF encodings, and both were superior to the conventional strategy. However, the TEO-based strategy was advantageous considering that it was approximately 35% faster than the HT-based strategy.

• 대한의용생체공학회:의공학회지
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• 제28권5호
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• pp.694-702
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• 2007

The adaptation effect originating from the chemical synapse between auditory nerve and inner hair cell gives advantage in accurate representation of temporal cues of incoming speech such as speech onset. Thus it is expected that the modification of conventional speech processing strategies of cochlear implant(CI) by incorporating the adaptation effect will result in considerable improvement of speech perception performance such as consonant perception score. Our purpose in this paper was to evaluate our new CI speech processing strategy incorporating the adaptation effect by the observation of auditory nerve responses. By classifying the presence or absence of speech from the auditory nerve responses, i. e. spike trains, we could quantitatively compare speech onset detection performances of conventional and improved strategies. We could verify the effectiveness of the adaptation effect in improving the speech onset representation characteristics.

• 말소리와 음성과학
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• 제8권3호
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• pp.67-78
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• 2016

This study examined the affective prosodic characteristics observed from the children with cochlear implant (CI, hereafter) and normal hearing (NH, hereafter) along with listener's perception on them. Speech samples were acquired from 15 normal and 15 CI children. 8 SLPs(Speech Language Pathologists) perceptually evaluated affective types using Praat's ExperimentMFC. When it comes to the acoustic results, there were statistically meaningful differences between 2 groups in affective types [joy (discriminated by intensity deviation), anger (by intensity-related variables dominantly and duration-related variables partly), and sadness (by all aspects of prosodic variables)]. CI's data are much more louder when expressing joy, louder and slower when expressing anger, and higher, louder, and slower when it comes to sadness than those of NH. The listeners showed much higher correlation when evaluating normal children than CI group(p<.001). Chi-square results revealed that listeners did not show coherence at CI's utterance, but did at those of NH's (CI(p<.01), normal(p=.48)). When CI utterances were discriminated into 3 emotional types by DA(Discriminant Analysis) using 8 acoustic variables, speed related variables such as articulation rate took primary role.

• 말소리와 음성과학
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• 제4권4호
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• pp.117-127
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• 2012

This research reports the prosodic characteristics (including articulation speech rate, pause characteristics, duration) of children with cochlear implants with reference to those of children with normal hearing. Subjects are 8-to 10-year-old children, balancing each number of gender as 24. Dialogue speech data are comprised of four types of sentence patterns. Results show that 1) there's a statistically meaningful difference on articulation speech rate between the two groups. 2) On pauses, they are not observed in exclamatory and declarative sentences in normal children. While imperative sentences show no statistical difference on the number of pauses between the two groups, interrogative sentences do. 3) Declarative, exclamatory, and interrogative sentences reveal statistical difference between the two groups in terms of the sentence's final two-syllable word duration, showing no difference on imperative sentences. 4) When it comes to the RFP (duration ratio of sentence final syllable to penultimate syllable), we no statistically meaningful difference between the two groups in all types of sentences exists. 5) Lastly, RWS (the ratio of sentence final two syllable word duration to that of whole sentence duration) shows statistical difference between two groups in imperative sentences, but not in all the rest types.

• 대한청각학회지
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• 제25권2호
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• pp.110-114
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• 2021

We report a case of hearing rehabilitation following combined cochlear implantation and ossiculoplasty. A 71-year-old patient visited the clinic for right-sided mixed hearing loss. We targeted neural and conductive components, performing two different operations simultaneously. At two months post-operative, the patient showed satisfactory results with respect to hearing threshold and speech comprehension. Our experience suggests that careful evaluation of patients and consideration of the diverse array of available treatment strategies can be used to provide personalized rehabilitation with maximal effectiveness. To the best of our knowledge, this is the first report to take such an integrated approach to treat hearing impairment and is thus likely to have clinical importance for otologists.