• 수산해양교육연구
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• 제25권2호
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• pp.341-348
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• 2013

The auditory thresholds for 7 specimens of the sharp toothed eel Muraensox cinerus were measured at 5 frequencies by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of the sharp toothed eel extended from 80Hz to 300Hz with the best sensitivity around 80Hz and 100Hz. In addition, the auditory thresholds over 200Hz increased rapidly. The mean auditory thresholds of the sharp toothed eel at the test frequencies of 80Hz, 100Hz, 200Hz and 300Hz were 87dB, 86dB, 105dB and 126dB, respectively. Auditory masking was determined for the sharp toothed eel by using masking stimuli with the spectrum level range of about 70~80dB (0dB re $1{\mu}Pa/\sqrt{Hz}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise. The noise spectrum level at the start of masking was distributed at the range of about 64dB within 80~100Hz. Critical ratio ranged from minimum 24dB to maximum 40dB at test frequencies of 80Hz~200Hz.

• 전기학회논문지
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• 제59권4호
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• pp.831-840
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• 2010

In this paper, we propose a hearing impairment simulator considering reduced frequency selectivity and asymmetrical auditory filter of the hearing impaired, and we verified the reduced frequency selectivity and asymmetrical auditory filter affected in speech perception through experiments. The reduced frequency selectivity has made embodied by spectral smearing using LPC(linear prediction coding). The shapes of auditory filter are asymmetrical different with each center frequency. Hearing impaired person which has hearing loss was differently changed with that of normal hearing people and it has different value for speech of quality through auditory filter. The experiments confirmed subjective test and objective test. The subjective experiments are composed of 4 kinds of tests: pure tone test, SRT(speech reception threshold) test, and WRS(word recognition score) test without spectral smearing, and WRS test with spectral smearing. The experiment of the hearing impairment simulator was performed from 9 subjects who have normal ears. The amount of spectral smearing was controlled by LPC order. The asymmetrical auditory filter of proposed hearing impairment simulator was simulated and then some tests to estimate the filter's performance objectively were performed. The objective experiment as simulated auditory filter's performance evaluation method used PESQ(perceptual evaluation of speech quality) and LLR(log likelihood ratio) for speech through auditory filter. The processed speech was evaluated objective speech quality and distortion using PESQ and LLR value. When hearing loss processed, PESQ and LLR value have big difference according to asymmetrical auditory filter in hearing impairment simulator.

• Journal of Audiology & Otology
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• 제25권2호
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• pp.65-71
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• 2021

Background and Objectives: In masking level difference (MLD), the masked detection threshold for a signal is determined as a function of the relative interaural differences between the signal and the masker. Study 1 analyzed the results of school-aged children with good school performance in the MLD test, and study 2 compared their results with those of a group of children with poor academic performance. Subjects and Methods: Study 1 was conducted with 47 school-aged children with good academic performance (GI) and study 2 was carried out with 32 school-aged children with poor academic performance (GII). The inclusion criteria adopted for both studies were hearing thresholds within normal limits in basic audiological evaluation. Study 1 also considered normal performance in the central auditory processing test battery and absence of auditory complaints and/or of attention, language or speech issues. The MLD test was administered with a pure pulsatile tone of 500 Hz, in a binaural mode and intensity of 50 dBSL, using a CD player and audiometer. Results: In study 1, no significant correlation was observed, considering the influence of the variables age and sex in relation to the results obtained in homophase (SoNo), antiphase (SπNo) and MLD threshold conditions. The final mean MLD threshold was 13.66 dB. In study 2, the variables did not influence the test performance either. There was a significant difference between test results in SπNo conditions of the two groups, while no differences were found both in SoNo conditions and the final result of MLD. Conclusions: In study 1, the cut-off criterion of school-aged children in the MLD test was 9.3 dB. The variables (sex and age) did not interfere with the MLD results. In study 2, school performance did not differ in the MLD results. GII group showed inferior results than GI group, only in SπNo condition.

• 대한청각학회지
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• 제25권2호
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• pp.65-71
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• 2021

Background and Objectives: In masking level difference (MLD), the masked detection threshold for a signal is determined as a function of the relative interaural differences between the signal and the masker. Study 1 analyzed the results of school-aged children with good school performance in the MLD test, and study 2 compared their results with those of a group of children with poor academic performance. Subjects and Methods: Study 1 was conducted with 47 school-aged children with good academic performance (GI) and study 2 was carried out with 32 school-aged children with poor academic performance (GII). The inclusion criteria adopted for both studies were hearing thresholds within normal limits in basic audiological evaluation. Study 1 also considered normal performance in the central auditory processing test battery and absence of auditory complaints and/or of attention, language or speech issues. The MLD test was administered with a pure pulsatile tone of 500 Hz, in a binaural mode and intensity of 50 dBSL, using a CD player and audiometer. Results: In study 1, no significant correlation was observed, considering the influence of the variables age and sex in relation to the results obtained in homophase (SoNo), antiphase (SπNo) and MLD threshold conditions. The final mean MLD threshold was 13.66 dB. In study 2, the variables did not influence the test performance either. There was a significant difference between test results in SπNo conditions of the two groups, while no differences were found both in SoNo conditions and the final result of MLD. Conclusions: In study 1, the cut-off criterion of school-aged children in the MLD test was 9.3 dB. The variables (sex and age) did not interfere with the MLD results. In study 2, school performance did not differ in the MLD results. GII group showed inferior results than GI group, only in SπNo condition.

• 수산해양기술연구
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• 제35권1호
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• pp.19-24
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• 1999

This paper is second part on the auditory thresholds and fish behaviors to the underwater sounds for luring of target species at the set-net in the coast of Cheju. In order to obtain the critical ratio of yellow tails(Seriola quinqueradiata) and the emission level of underwater sound for luring of them, we make experiments to measure the auditory threshold of them using conditioning with electric shock. In state that the white noise with 10dB higher sound pressure level than ambient noise is emitted, the auditory thresholds of yellow tails are measured with 100~116.5dB and they are higher than those in state of no emission of white noise by the masking effects of it. Although sound pressure level of background noise go down, the auditory thresholds go up with frequency above than 300Hz.The critical ratio of yellow-tails in frequency of 80Hz, 100Hz, 200Hz, 500Hz, 800Hz are 46dB, 40dB, 50dB, 52dB, 60dB, 70dB respectively. The sound pressure level of which the signal sound is recognized by yellow tails under the ambient noise is above 100dB and the critical ratio of them is above 40dB.

• 음성과학
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• 제10권4호
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• pp.181-187
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• 2003

This paper introduces a new zinc coated copper wire electrode with coiled cone shape which has low surface resistance and tolerance to the motion artifact for promontory stimulation electrically auditory brainstem responses (PSEABR). Auditory brainstem responses (ABR) can be used to predict hearing threshold level with a great deal of accuracy particularly for a young child who cannot cooperate mechanically and some hearing impaired who are exaggerating a hearing loss for economic compensation. While severe profound sensorineural hearing losses may not be implemented by auditory potentials, PSEABR is proven as a useful tool even for some sensorineural related hearing impaired. It was shown that PSEABR gives the electrical stimuli to promontory of the cochlear instead of giving acoustic stimuli. For this reason, PSEABR can be used as an alternative for cochlear implantation, and can also be used as an optimal device selection and neural information for MAP. It was found that the role of electrode is very important in PSEABR. Even though this cone-shaped electrode was applied in animal experiments, waveforms are well produced by PSEABR. Thus, it was concluded that cone-shaped electrode turned out to be a useful preoperative audiological evaluation tool in deciding time for cochlear implantation surgery.

• 수산해양기술연구
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• 제39권4호
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• pp.269-275
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• 2003

제주도 연안 정치망의 여름철 주 어획대상인 잿방어를 실험어로 하여, 음향을 이용한 어군행동 제어, 음향순치 등 바다목장 조성을 위한 어군의 관리, 사육, 어획기술에 이용할 기초자료를 제공할 목적으로 육상수조에서 수중 가청 저주파음과 전기충격을 이용하여 음향 학습 시킨 후, 주파수와 음압을 변화시켜가면서 잿방어의 섬전도를 도출 하여 심박간격의 변화로부터 청각문턱치, 청각임계비를 측정하였다. 자연환경소음에서 잿방어의 청각문턱치는 측정 주파수 80∼800 HZ의 수중 가청음을 모두 인식하였고, 측정 주파수 200∼500 HZ 에서 청각 감도가 양호하였으며, 측정 주파수 300 Hz에서 평균 음압 94.5 dB, 표준편차 4.5 dB로 가장 낮은 청각문턱치를 보였다. 평균 음압을 65 dB, 70 dB, 75 dB의 3단계로 변화시킨 백색잡음 방성으로 측정한 잿방어의 청각임계비는 측정 주파수 80, 100, 200, 300, 400, 500, 800 HZ에서 각각 평균 음압 45.9, 52.8, 42.5, 36.4, 38.6, 39.4, 44.4 dB이었다. 측정 주파수 300 HZ, 400 HZ 그리고 500 HZ 에서는 백색잡음 중에서 측정음을 식별하는 능력이 다른 측정 주파수에 비하여 우수했다. 잿방어가 주파수 300 HZ의 수중 가청음을 충분히 인식하기 위해서는 최저 100 dB 이상의 음압 강도가 펼요하며 환경 소음이 존재하는 환경에서는 소음 스펙트럼 음압 레벨보다 약 35 dB 이상 크게 방성할 펼요가 있다.

• 수산해양교육연구
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• 제25권6호
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• pp.1381-1388
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• 2013

In order to improve the availability of underwater sound by the fundamental data on the hearing ability, the auditory thresholds for the bambooleaf wrasse pseudolabrus japonicus were determined at 80Hz, 100Hz, 200Hz, 300Hz, 500Hz and 800Hz by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of the bambooleaf wrasse extended from 80Hz to 800Hz with the best sensitivity around 100Hz and 200Hz. In addition, the auditory thresholds over 300Hz increased rapidly. The mean auditory thresholds of the bambooleaf wrasse at the test frequencies, 80Hz, 100Hz, 200Hz, 300Hz, 500Hz and 800Hz were 100dB, 95.1dB, 94.8dB, 109dB, 121dB and 125dB, respectively. Auditory critical ratios for the bambooleaf wrasse were measured using masking stimuli with the spectrum level range of about 70, 74, 78dB (0dB re $1{\mu}Pa/\sqrt{Hz}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise. The Auditory masking by the white noise spectrum level was stared over about 60dB within 80~300Hz. Critical ratios to be measured at frequencies from 80Hz to 300Hz were minimum 33dB and maximum 39dB.

• 수산해양교육연구
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• 제28권2호
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• pp.384-390
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• 2016

The purpose of this paper is to improve the availability of underwater sound by the fundamental data on the hearing ability of Redlip croaker Pseudosciaena polyactis, which is cultured according to the cultivation technology, recently. The auditory thresholds of Redlip croaker were determined at 6 frequencies from 80Hz to 800Hz by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of the Redlip croaker extended from 80Hz to 800Hz with the best sensitive frequency range including little difference in hearing ability from 80Hz to 500Hz. In addition, the auditory thresholds over 800Hz increased rapidly. The mean auditory thresholds of the Redlip croaker at the test frequencies from 80Hz to 800Hz were 90.7dB, 93.4dB, 92.9dB, 94.4dB, 95.5dB and 108dB, respectively. Auditory masking for the redlip croaker was measured using masking stimuli with the spectrum level range of about 66, 71, 75dB (0dB re $1{\mu}Pa/{\sqrt{Hz}}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise. The Auditory masking by the white noise spectrum level was stared over about 70dB within 80~500Hz. Critical ratio ranged from minimum 20.7dB to maximum 25.5dB at test frequencies of 80Hz~500Hz.

• Journal of Audiology & Otology
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• 제24권1호
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• pp.10-16
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• 2020

Background and Objectives:The blockage of adenosine receptors by caffeine changes the levels of neurotransmitters. These receptors are present in all parts of the body, including the auditory and vestibular systems. This study aimed to evaluate the effect of caffeine on evoked potentials using auditory brainstem responses (ABRs) and cervical vestibular-evoked myogenic potentials (cVEMPs) in a double-blind placebo-controlled study. Subjects and Methods: Forty individuals (20 females and 20 males; aged 18-25 years) were randomly assigned to two groups: the test group (consuming 3 mg/kg pure caffeine powder with little sugar and dry milk in 100 mL of water), and the placebo group (consuming only sugar and dry milk in 100 mL water as placebo). The cVEMPs and ABRs were recorded before and after caffeine or placebo intake. Results: A significant difference was observed in the absolute latencies of I and III (p<0.010), and V (p<0.001) and in the inter-peak latencies of III-V and I-V (p<0.001) of ABRs wave. In contrast, no significant difference was found in cVEMP parameters (P13 and N23 latency, threshold, P13-N23 amplitude, and amplitude ratio). The mean amplitudes of P13-N23 showed an increase after caffeine ingestion. However, this was not significant compared with the placebo group (p>0.050). Conclusions: It seems that the extent of caffeine's effects varies for differently evoked potentials. Latency reduction in ABRs indicates that caffeine improves transmission in the central brain auditory pathways. However, different effects of caffeine on auditory- and vestibular-evoked potentials could be attributed to the differences in sensitivities of the ABR and cVEMP tests.