• Korean Journal of Audiology
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• v.23 no.3
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• pp.153-159
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• 2019

Background and Objectives: We aim to explore the effects of residual auditory steady state response (ASSR) on cochlear implantation (CI) outcomes in children lacking auditory brainstem responses (ABRs). Subjects and Methods: We retrospectively reviewed the data of child CI recipients lacking ABRs. All ears were divided into two groups: with residual ASSR and without ASSR. For each frequency, the T- and C-levels and the electrical dynamic ranges of postoperative 3-month and 1-year mappings were compared between the groups. To evaluate speech perception, patients who received simultaneous bilateral CIs were divided into two groups: group 1 exhibited responses at all frequencies in both ears; in group 2, at least one ear evidenced no response. The Categories of Auditory Perception (CAP) and Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS) scores were compared between the groups. Results: We enrolled 16 patients. At 2 kHz, the postoperative 3-month and 1-year T-levels of patients with residual hearing were lower than those of hearing loss group (p=0.001, p=0.035). In residual hearing group, the ASSR threshold correlated positively with the postoperative 1-year T-level (p=0.012, R²=0.276) and C-level (p=0.002, R²=0.374). Of 10 simultaneous bilateral CI recipients, 5 exhibited ASSRs at all frequencies and the other 5 showed no response at ≥1 frequency. The latter had higher CAP scores at the postoperative 1-year (p=0.018). Conclusions: In children exhibiting hearing loss in ABR testing, residual hearing at 2 kHz ASSR correlated positively with the post-CI T-level. Those with ASSRs at all frequencies had significantly lower CAP scores at the postoperative 1year. CI should not be delayed when marginal residual hearing is evident in ASSR.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.171-174
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• 2004

본 논문은 Hspice 를 사용한 달팽이관 생역학의 능동적이며 선형적인 1 차 그리고 2 차원 모델링을 보여준다. Hspice 모델링의 장점은 달팽이관 생역학을 아날로그 IC 칩으로 구현할 수 있다는 점이다. 즉 Biochip 으로 설계하는데 활용된다. 본 논문은 달팽이관 생역학을 어떻게 전기회로 모델화한 뒤, 다시 어떻게 Hspice 코드로 표현하는 가를 보여준다. 달팽이관 회로가 Hspice 코드 실행을 위해 변형되어야만 하는 과정을 상세히 보여준다. 1 차원의 결과와 2 차원의 결과를 비교하고 있다.

• Journal of Biomedical Engineering Research
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• v.3 no.2
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• pp.105-112
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• 1982

Using electronic cochlear implant system, we studied in cats the difference in the response of the brain stem evoked response (BER) during the stimulation with the acoustic signals and the electric signals. These brain stem electric responses were analyzed using the integral pulse frequency modulation method of the auditory nervous system. Animal experimental results and the analysis show that the carrier wave hasimprored the frequency specificity. of the electronic auditory prosthesis.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.680-683
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• 1987

The speech signal processing in the auditory system can be analysized based on two representations : Average discharge rate and Temporal discharge pattern. But the average discharge rate representation is restricted by the narrow dynamic range because of the rate saturation and the two tone suppression phenomena, and the temporal discharge pattern representation needs a sophisticate frequency analysis and synchrony measure. In this paper, a simple representation is proposed : using a model considering the interaction of Cochlear fluid-BM movement and a haircell model, the feature of speech signals (formant frequency and pitch of vowels) is easily estimated in the Average Synchronized Rate.

• Proceedings of the KSLP Conference
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• 2003.11a
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• pp.144-145
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• 2003

고심도의 청각장애를 가진 아동의 음성은 높은 음도와 강도, 과비음 등 건청 아동과는 매우 다른 특성을 나타낸다. 그 중에서 초분절적인 요소에 속하는 억양은 청각장애 아동의 경우 단조롭고 높낮이 변화가 크지 않아서 의미전달에 어려움을 주는 중요한 요소이다. 청력손실이 고심도인 경우 수술을 하게 되면 청각적 수용능력을 높일 수 있어, 최근 부각되고 있는 인공 와우 이식수술을 받은 아동 또한 이러한 억양에서의 문제는 완전히 해결 받지 못하고 있다. 따라서 이 연구에서는 인공 와우 이식수술을 받은 청각장애 아동이 건청 아동과 억양에서 어떠한 차이를 드러내는지에 대해 알아보고자 하였다. (중략)

• The Journal of the Acoustical Society of Korea
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• v.4 no.3
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• pp.8-15
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• 1985

본 논문에서는 코클리어 기저막 운동에 관한 전기적 모델링을 래더회로를 이용하여 구현하였다. Budak 의 이론에 근거한 이득이 1보다 큰 RC 수동회로를 이용하여 귀에서의 Place Principle을 만족시 키는 특성을 갖는 모델을 제시하였으며 이는 간단한 회로를 첨가시킬시에 이득이 1보다 큰 주파수를 검 지해낼 수도 있다. 컴퓨터 Simulation을 이용한 전달함수 분석에서는 특이한 형태 의 전압전달함수를 얻 을 수 있었으며, 연구결과, 본 모델은 코클리어 기저막운동을 표현하기에 적합하다는 결론을 얻을 수 있 었다. 본 모델은 임상의학이나 그 외의 공학분야등에 이용이 가능하리라고 본다.

• Journal of Korean Neurosurgical Society
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• v.45 no.4
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• pp.231-235
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• 2009

Objective : While many factors contribute to aging, changes in calcium homeostasis and calcium related neuronal processes are likely to be important. High intracellular calcium is toxic to cells and alterations in calcium homeostasis are associated with changes in calcium-binding proteins, which confine free $Ca^{2+}$. We therefore assayed the expression of the calcium binding proteins calretinin and calbindin in the central auditory nervous system of rats. Methods : Using antibodies to calretinin and calbindin, we assayed their expression in the cochlear nucleus, superior olivary nucleus, inferior colliculus, medial geniculate body and auditory cortex of young (4 months old) and aged (24 months old) rats. Results : Calretinin and calbindin staining intensity in neurons of the cochlear nucleus was significantly higher in aged than in young rats (p<0.05) The number and staining intensity of calretinin-positive neurons in the inferior colliculus, and of calbindin-positive neurons in the superior olivary nucleus were greater in aged than in young rats (p<0.05). Conclusion : These results suggest that auditory processing is altered during aging, which may be due to increased intracellular $Ca^{2+}$ concentration, consequently leading to increased immunoreactivity toward calcium-binding proteins.

• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.269-275
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• 2016

This study has investigated the feasibility of 980-nm low-energy pulsed near-infrared laser stimulation to evoke auditory responses, as well as the effects of radiant exposure and pulse duration on auditory responses. In the experiments, a hole was drilled in the basal turn of the cochlea in guinea pigs. An optical fiber with a 980-nm pulsed infrared laser was inserted into the hole, orientating the spiral ganglion cells in the cochlea. To model deafness, the tympanic membrane was mechanically damaged. Acoustically evoked compound action potentials (ACAPs) were recorded before and after deafness, and optically evoked compound action potentials (OCAPs) were recorded after deafness. Similar spatial selectivity between optical and acoustical stimulation was found. In addition, OCAP amplitudes increased with radiant exposure, indicating a photothermal mechanism induced by optical stimulation. Furthermore, at a fixed radiant exposure, OCAP amplitudes decreased as pulse duration increased, suggesting that optical stimulation might be governed by the time duration over which the energy is delivered. Thus, the current experiments have demonstrated that a 980-nm pulsed near-infrared laser with low energy can evoke auditory neural responses similar to those evoked by acoustical stimulation. This approach could be used to develop optical cochlear implants.

• Phonetics and Speech Sciences
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• v.6 no.2
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• pp.55-64
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• 2014

This study measured formant bandwidths of profound hearing impaired children and examined the characteristics of their articulation. For this study, 10 cochlear implanted children(CI), 10 hearing aid children(HA) and 10 normal hearing children(NH) were asked to read 7 Korean vowels(/ɑ, ʌ, o, u, ɯ, i, ɛ/). The subjects' readings were recorded by NasalView and analyzed by Praat. The analysis of the formant bandwidths explains the degree of vocal fold opening and the characteristics of radiation. Through the analysis of formant bandwidth, we can see that the hearing-impaired maintain vocal fold tension when they speak high vowels and characteristics of radiation. Narrower B1 means better maintain vocal fold tension, wider B2 means more front and wider B3 means the rounder lips. CI's B1 was widest and NH's was narrowest. And females' B1 was wider than males'. Among vowels, B1 of /a/ was widest, and B1 of /i/ was narrowest. In the case of B2, HA and NH's B2 was wider than CI's. Females' B2 was wider than males'. And B2 of /i/ was widest, and B2 of /ʌ/ was narrowest. In the case of B3, NH's was widest, and CI's was narrowest. Males' was wider than females'. Among vowels, B3 of /o/ was widest, and B3 of /ɛ/ was narrowest. As a result, first, through the analysis of B1, we can find that NH and males could better maintain vocal fold tension than the hearing-impaired or females, and all children articulate /i/ with vocal fold tension than other vowels. Second, through the analysis of B2, NH and HA articulate vowels with the weaker rounded than CI does. And females articulate vowels with the weaker rounded than males do. Third, through the analysis of B3, NH articulate vowels with the rounder than HA or CI do, and males articulate vowels with the rounder than females do. Through the results, we can expect that the analysis of formant bandwidth will be applied to the therapy of articulation for the hearing-impaired with hearing aids or cochlear implant.

• Speech Sciences
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• v.9 no.2
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• pp.193-202
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• 2002

The purpose of this study is to examine the phonological awareness of hearing impaired children. A number of researches indicate that hearing impaired children have articulation disorders due to their impaired auditory feedback. However, in children who have the ability to distinguish certain phonemes, they sometimes show misarticulation of the phonemes. Phonological awareness refers to recognizing the speech-sound units and their forms in spoken language (Hong, 2001). The subjects who participated in the experiment are composed of four hearing impaired children (3 cochlear implanted children and 1 hearing aided child). Phonological Awareness was evaluated by the test battery developed by Paik et al. (2001). The subtests consisted of rhyme matching, onset matching I II, word initial segmentation and matching I II. If the children asked for retelling, it was retold to a maximum of 4 times. Each item score was 1 point. The results were compared to those of Paik et al. (2001). The results of study were that subject 1 showed superior rhyme matching ability, subjects 2 and 3 fair ability, and subject 4 inferior ability. In onset matching I, all subjects showed inferior ability except for subject 3. Interestingly, subjects 1 showed the lowest onset matching I score. In word initial segmentation and matching I, subjects 1 and 4 showed inferior ability and subjects 2 and 3 showed fair ability. In onset matching II, subject 2 showed the perfect score 10 even though she showed very low score. In word initial segmentation and matching II, only subjects 2 and 3 showed appropriate levels of the skill. The results show that the phonological awareness of hearing impaired children is different from that of normal children.