• The Journal of the Acoustical Society of Korea
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• v.24 no.3E
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• pp.77-86
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• 2005

This paper shows one and two dimensional active linear modeling of cochlear biomechanics using Hspice. The advantage of the Hspice modeling is that the cochlear biomechanics may be implemented into an analog Ie chip. This paper explains in detail how to transform the physical cochlear biomechanics to the electrical circuit model and how to represent the circuit in Hspice code. There are some circuit design rules to make the Hspice code to be executed properly.

• Journal of Biomedical Engineering Research
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• v.12 no.4
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• pp.285-294
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• 1991

Two types of the speech signal processores (SSP) for the cochlear a prosthesis are designed. One is designed using the cochlear model and the other is designed using the information (formant, pitch, intensity) extraction method. For these, some cochlear model and acoustic information extraction method are proposed. The result shows the SSP of the cochlear model type contain more acoustic cues than that of information extraction type. On the other hand, stimulus signal is clear and algorithm is simple in the SSP of the information ex traction type.

• Speech Sciences
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• v.14 no.4
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• pp.213-220
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• 2007

This study investigates the voice quality including F0, jitter, shimmer, and NHR for the children with cochlear implant (CI group) and those with normal hearing (NH group). The CI group was further classified two sub-groups depending upon the time of surgery (i.e. under four years vs. over four years). Three corner vowels (e.g. /a/, /i/, /u/) with extended vocalization were used and analyzed with Multi-Dimensional Voice Program (Kay Elemetrics, Model 4300). The statistics were made in two independent sample t-test with SPSS 11.5. The results can be summarized as follows: (1) The children with cochlear implanted before 4 years of age had very similar data with the NH group except for the vowel /a/. (2) The children with cochlear implanted after 4 years of age, however, indicated significant differences in Fo (/a/, /i/, /u/), Jitter (/e/), shimmer (/a/, /i/, /u/) and NHR(/a/) in all three vowels. It is concluded that the early CI surgery and the early intervention would be very important to maintain better voice quality.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1978.06a
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• pp.9.1-10
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• 1978

Recently the authors have observed various wave-forms by insertion of induction coil into the scala tympani as well as attached outer device in the outside of the body in damaged hair cells of the cats. In the cochlear nerve. action potential indicated different polarities induced by examination of the bundle of the cochlear nerve fibers. Impulse wave-form as a result of excitation of cohlear nerve fibers showed bipolar wave-form such as negative 1 and positive 1. Therefore action potential showed also bipolar wave-form as above mentioned. We can obtained suitable response with above mentioned outer and inner device as an exact oscillogram.

• Phonetics and Speech Sciences
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• v.2 no.3
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• pp.171-178
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• 2010

This study examined the relationship between speech intelligibility and comprehensibility for hearing impaired children with cochlear implants. Speech intelligibility was measured by orthographic transcription method for acoustic signal at the level of words and sentences. Comprehensibility was evaluated by examining listener's ability to answer questions about the contents of a narrative. Speech samples were collected from 12 speakers(age of 6~15 years) with cochlear implants. For each speaker, 4 different listeners(total of 48 listeners) completed 2 tasks: One task involved making orthographic transcriptions and the other task involved answering comprehension questions. The results of the study were as follows: (1) Speech intelligibility and comprehensibility scores tended to be increased by decreasing of severity. (2) Across all speakers, the relationship was significant between speech intelligibility and comprehensibility scores without considering severity. However, within severity groups, there was the significant relationship between comprehensibility and speech intelligibility only for moderate-severe group. These results suggest that speech intelligibility scores measured by orthographic transcription may not accurately reflect how well listener comprehend speech of children with cochlear implants and therefore, measures of both speech intelligibility and listener comprehension should be considered in evaluating speech ability and information-bearing capability in speakers with cochlear implants.

• Journal of Korean Clinical Nursing Research
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• v.21 no.2
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• pp.243-251
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• 2015

Purpose: The aim of this study was to develop an educational program for the children's guardian with cochlear implants in order to provide knowledge and information about cochlear implants. Methods: The educational program was developed based on a literature review, potentially relevant website analysis, and validation by an expert group. Two out of twenty-two educational items under four domains that had item-level content validity index (CVI) greater than 0.8 by the ten experts were finally selected and used. After the children's guardian participated in this educational activity through a specially designed booklet and DVD, the effectiveness of the program was evaluated. Results: A total of 8 children's guardian participated in the program. Their knowledge levels significantly increased after participating the program (mean $15.0{\pm}3.02$ vs. $19.0{\pm}0.93$, Z= 2.371, p=.018). Satisfaction levels with the program was high, $4.1{\pm}0.87$ out of 5. Conclusion: This newly developed educational program for the children's guardian with cochlear implants is proved to be effective and can be used in nursing practice. In addition, the participants seemed to be satisfied with the program. Furthermore, this program may also improve the effects of adult with cochlear implants.

• Phonetics and Speech Sciences
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• v.6 no.3
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• pp.91-99
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• 2014

Although it is well documented that patients with cochlear implant experience hearing difficulties when processing their first language, very little is known whether or not and to what extent cochlear implant patients recognize segments in a second language. This preliminary study examines how Korean learners of English identify English segments in a normal hearing and cochlear implant simulation conditions. Participants heard English vowels and consonants in the following three conditions: normal hearing condition, 12-channel noise vocoding with 0mm spectral shift, and 12-channel noise vocoding with 3mm spectral shift. Results confirmed that nonnative listeners could also retrieve spectral information from vocoded speech signal, as they recognized vowel features fairly accurately despite the vocoding. In contrast, the intelligibility of manner and place features of consonants was significantly decreased by vocoding. In addition, we found that spectral shift affected listeners' vowel recognition, probably because information regarding F1 is diminished by spectral shifting. Results suggest that patients with cochlear implant and normal hearing second language learners would experience different patterns of listening errors when processing their second language(s).

• Phonetics and Speech Sciences
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• v.6 no.2
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• pp.89-96
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• 2014

This study measured speech intelligibility in relation to the vowel space area and the perception of the listener through acoustic analysis of children who had received cochlear implants. It also provided basic data in the evaluation of speech intelligibility by analyzing the correlation between the vowel space area and speech intelligibility. As a research method, the vowel space area was analyzed by obtaining the value of $F_1$, $F_2$ in children three years after receiving cochlear implants, and compared them to normal children by measuring speech intelligibility through interval scaling. A product-moment correlation analysis was conducted to investigate the correlation. Results showed that the vowel space area of the children who had received cochlear implants was significantly different from that of the normal children, though their speech intelligibility showed similar points to those of the normal children. The results of the correlation analysis on the vowel space area and speech intelligibility showed no significant correlation. Therefore, the period of improving intelligibility after receiving cochlear implants and the objective standards of the vowel space area could be established. In addition, the acoustic rating was required to increase the accuracy of the objective measurement in the evaluation of speech intelligibility.

• Archives of Craniofacial Surgery
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• v.20 no.5
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• pp.319-323
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• 2019

Cochlear implant extrusion, which is a common complication of cochlear implants, is generally repaired by a well visualized soft-tissue flap. A 61-year-old female patient with a medical history of schizophrenia who had a skin ulcer that caused cochlear implant extrusion, but that would be a stronger statement was referred to our department for removal of the implant and reconstruction of the resultant scalp defect. Accordingly, the broad defect was covered via rotation of a temporoparietal fascia flap (TPFF) using the superficial temporal artery, with the pedicle in the preauricular region as the pivot point. Coverage of TPFF was achieved with a split-thickness skin graft using the scalp as the donor site, which led to a quick recovery after the operation and satisfactory results in terms of aesthetics. This case suggests that a TPFF might be used as a flexible flap with low donor site morbidity for reconstructing cases of cochlear implant extrusion accompanied by a large full-layer scalp defect.

• Molecular & Cellular Toxicology
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• v.5 no.2
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• pp.133-140
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• 2009

Caveolin may be a molecular target for modulation of aging process in cochlear hair cells and have association with oxotoxicity. First we investigated the basal expression of caveolin-1, caveolin-2, caveolin-3, nitric oxide synthase, and superoxide dismutase in UB/OC-1 cochlear hair cell line. By using a RNA interference technique, we investigated whether down-regulation of caveolin influenced telomerase activity and reactive oxygen species (ROS) production in cochlear hair cells. In addition, cisplatin and gentamycin, known ototoxic drugs, were administered to the cochlear cells to determine their impact on caveolin expression. Further attempts at elucidating cellular aging mechanism with caveolin and ototoxic drugs were carried out. The main discoveries were the presence of caveolin-1 in UB/OC-1 cells and that down-regulation of caveolin-1 reduced protein kinase A activity. Telomerase was activated by caveolin down-regulation and caveolin down-regulation inhibited oxidative stress at the mitochondrial level. When cisplatin and gentamycin were administered to the cochlear hair cells during a caveolin expression state, a decrease in telomerase activity and increase ROS activity was observed. Caveolin-1 may modulate the senescent mechanisms in cochlear cells. An increase in caveolin-1 levels can lead to ROS production in the mitochondria which may cause ototoxicity.