• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.10
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• pp.837-843
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• 2012

Compared to conventional pure-tone audiometer(PTA), the computerized one has several advantages such as relatively lower price, better flexibility, and easy operation. In addition, the computerized PTA can be easily extended to support automatic calibration. In this study, the support of automatic calibration in the computerized PTA has been addressed using the Linux realtime spectrum analyzer and network. In terms of accuracy, the new automatic calibration machine was compared to the existing manually operated one. According to the comparison, normal operation and high accuracy were observed within the scope of the international standard.

• Journal of Oral Medicine and Pain
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• v.38 no.4
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• pp.333-338
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• 2013

Purpose: A growing number of studies have been providing evidence for neural connections between the auditory and somatosensory systems that might be a critical part of the mechanisms underlying certain forms of tinnitus. The aim of this study was to investigate the effect of temporomandibular joint (TMJ) movements on tinnitus. Methods: One hundred sixty-three tinnitus patients participated in this study. All patients underwent a thorough audiological examination including pure-tone audiometry, tinnitus handicap inventory, and evaluation of tinnitus loudness, frequency and severity on a visual analog scale. Somatic testing consisting of nine forceful jaw muscle contractions was performed to evaluate the effect of TMJ movements on modulation of tinnitus. Results: 66.9% of patients had unilateral tinnitus. Somatic testing modulated tinnitus loudness in 125 ears (57.6 %) of 217 ears tested. An increase in tinnitus loudness was observed more often than a decrease. Loudness was most commonly increased by opening and clenching jaw. Tinnitus could be induced by opening, clenching and deviating jaw to the left. Conclusion: Our study showed evidence that TMJ movements may aggravate and even evoke tinnitus and somatic testing can be used for evaluating if stimulation of the TMJ induces or aggravates tinnitus.

• Korean Journal of Occupational Health Nursing
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• v.12 no.2
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• pp.146-155
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• 2003

This study was conducted for investigating the status of management of preemployment health examination and to have an effect on the worker's employment. Health managers of 103 companies in Incheon metropolitan city and Gyeonggi were interviewed by telephone. Of 103 companies, 67(65.1%) said they don't hire the applicants who have an active pulmonary tuberculosis, 80(77.7%) companies said they health HBV carrier is acceptable but active HBV carrier is not 29(28.2%) companies said they don't hire the applicants who have a hypertension or diabetes mellitus, 42(40.8%) companies said they don't hire the applicants who have a hearing disturbance. If HIVD is suspicious in X-ray lumbar-sacral region, 37(78.7% of 47 companies) said they do not hire the applicants. 29(35% of 83 companies) said they cancel the employment of the applicants who are suspicious of noise induced hearing loss on preplacement health examination. From our survey, preemployment health examination was utilizing mainly as a tool for the selection of health employees who don't have a disease. Furthermore, in many companies, additional test items are being included and getting more strict the selection criteria for preemployment health examination. For the right use of preemployment health examination, author suggested that further studies were needed to select the adequate test items and establish the reasonable criteria for preemployment health examination.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.3
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• pp.218-223
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• 2006

Sensorineural hearing loss is frequently found in patients with chronic renal failure (CRF). There have been many efforts to elucidate the etiologic factors of hearing loss in patients with CRF. However, there was not any clear identified cause of hearing loss. This study was undertaken to evaluate the activity of mitochondrial respiratory chain (MRC) in CRF patients with hearing impairment. To determine MRC activity, peripheral blood cells were obtained from CRF patients with hearing impairment receiving dialysis and normal subjects without any hearing problems. MRC activity of complex I and complex III was measured by the Trounces method. In MRC activities between the normal subjects group and CRF patients with hearing problems, the complex I and III activities of CRF patients with hearing problems were 63% and 85% compared with normal subjects (p<0.01). These results suggest that the activity of MRC may be implicated in the underlying mechanism of the hearing impairment in CRF patients, through mitochondrial DNA mutations at MRC complex I region with a decrement of MRC activity.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.11
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• pp.854-860
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• 2014

Workers engaged in car inspection works have been exposed to many occupational hazards including noise, particulate matter, and volatile organic substances. Noise-induced hearing loss(NIHL) is one of the leading health hazards among Korean workers. The aim of this study is to evaluate the noise levels in several car inspection shops by introducing the evaluation methods of KMOEL/OSHA and ACGIH. Six sites in central area of Korea were selected to monitor the noise levels of workers by personal and area sampling methods for two consecutive days in spring, summer, fall and winter seasons. Dosimeters have been used for this noise monitoring program. Obtained noise levels by the evaluation method according to KMOEL/OSHA are the range of 50.2~88.2 dB(A), these are lower than KOEL/OSHA standards level of 90 dB(A). But highest noise by ACGIH's evaluation methodology is recorded 92.3 dB(A) and is greater than NIHL standard level of 85 dB(A). So that many workers may be exposed to the dangerous noise environment. The higher the car inspection loads daily, the higher the noise levels in the sites. Seasonal fluctuation of noise levels at the process might give monitoring results with high variations. Area noise levels showed higher than those of personal sampling, which illustrate some high noise spots in the car inspection areas.

• The Journal of the Acoustical Society of Korea
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• v.41 no.1
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• pp.45-51
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• 2022

Sound quality evaluation is one of the psychoacoustic methods to measure subjective judgements for sound color. The purpose of this study is to investigate sound quality benefits of bimodal users by comparing sound quality scores between bimodal hearing condition and unilateral cochlear implant(CI) condition as a preliminary study. Thirteen bimodal users and seven unilateral CI users were participated in this study. Audiologists performed pure tone and speech audiometry and measured functional gain and real-ear insertion gain. Subjective assessment of sound quality was followed with four sounds including violin sound, male and female voices, and refrigerator noise. Participants judged the sound quality with six sound quality index. Bimodal users showed mean 0.8 points more sound quality improvements in bimodal condition than unilateral CI condition. Group comparison between bimodal and unilateral CI users showed no differences. A follow-up study of sound quality tools and methods should be considered to evaluate subjective bimodal benefits of cochlear implant users.

• Clinical and Experimental Pediatrics
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• v.52 no.11
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• pp.1221-1227
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• 2009

Purpose:To identify the risk factors for poor neurodevelopmental outcomes in high-risk neonates. Methods:We studied 94 infants admitted to the neonatal intensive care unit at the Sanggye Paik Hospital between January 2002 and November 2005 and evaluated the follow-up data. The following events were considered as risk factors: ${\leq}32$ weeks of gestation, very low birth weight, Apgar scores of less than 5, neonatal resuscitation, neonatal seizure, congenital infection, and abnormalities in cranial ultrasound or magnetic resonance imaging (MRI). The infants who had any one of these risk factors were included. They were evaluated at their mean corrected age of 13.84${\pm}$8.03 months. Mental and Psychomotor Developmental Indices (MDI, PDI) were determined by a clinical psychologist using the Bayley Scales of Infant Development II. Results:The mean MDI and PDI of all the patients were 96.28${\pm}$26.70 and 94.00${\pm}$22.80, respectively. Abnormalities on cranial ultrasound or MRI were significant predictors of both low MDI (P<0.05) and low PDI (P<0.001). These abnormalities showed a stronger association with low PDI than with low MDI. The infants with periventricular leukomalacia had the lowest MDI and PDI ($70.10{\pm}28.68$ and $69.70{\pm}24.91$, respectively). Apgar score at 1 minute and very low birth weight were also significant predictors for low PDI (P<0.05, P<0.05, respectively). Conclusion:Image findings with cranial ultrasound or MRI were the strongest predictors of neurodevelopmental outcome. Periventricular leukomalacia was the best predictive factor for mental and psychomotor development.

• Pediatric Infection and Vaccine
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• v.24 no.1
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• pp.65-70
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• 2017

Cytomegalovirus (CMV) infection is one of the most common congenital infections. The first case of discordant congenital CMV infection in twins occurred in Korea. A 31-year-old woman became pregnant with twins (dichorionic-diamniotic). An elective caesarean section was performed at 37 weeks. The first baby was male, weighing 2,410 g with an Apgar score of 8/9. The second baby was female, weighing 1,380 g with an Apgar score of 5/8. She had experienced intrauterine growth retardation, and presented with microcephaly, micrognathia, and joint stiffness. During the work-up for discordant twins, the second baby's serum test was positive for CMV immunoglobulin M. Her urine, blood, and cerebrospinal fluid (CSF) were CMV polymerase chain reaction positive. The first baby's CMV tests were negative. Ophthalmologic exam and audiometry performed on the second baby showed CMV retinitis and bilateral sensorineural hearing loss. She was treated with intravenous ganciclovir. Currently, she is bed-ridden and has significant developmental delay. Although the causes of discordant congenital CMV infection in twins are unclear, this case shows that discordant congenital CMV infection should be considered in twins with significant differences in intrauterine growth or clinical symptoms after birth.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1978.06a
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• pp.8.3-8
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• 1978

In normal auditory systems, the difference between the bone conduction thresholds obtained with the test ear opened and occluded in low frequency signals below 1, 000Hz is about 10~25 dB. But no difference in these thresholds suggests the presence of a lesion in the conductive mechanism. Sullivan added the differences in these thresholds at 250Hz, 500Hz and 1,000Hz and called "Occlusion Index". In oder to study the audiological significance, we have measured the occlusion index in 40 ears of normal persons, 20 ears of chronic otitis media patients and 20 ears of sensori-neural hearing impairment patients. We also measured the static compliance in 40 normal ears and observed the correlation with the occlusion index. The results are as follows: 1. Occlusion index was 33. $10\pm10.63dB$ in normal group, $3.10\pm3.03dB$ in chronic otitis media; group, $28.10\pm15.17dB$ in sensori-neural group. 2. Static compliance in normal group was $0.61\pm0.31cc$ (0.22~1.75cc) 3. Occlusion index showed inverse proportion to static compliance.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.1
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• pp.73-79
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• 2017

It is difficult to detect the adult hearing loss after the language acquisition because of its slow progression, which can be evaluated voluntarily and actively when the appropriate tools are provided. Smartphones are one of useful tools, and they can utilize surveys and/or applications for hearing screening. This study aims to verify the possibility as a tool discovering delayed acquired hearing losses by comparing the pure tone screening application (app_PTS) which was recently developed by our research team and hearing handciap inventory (HHI). The subjects were 22 people whose age ranges from 10s to 80s. For pure tone averages (PTAs), hearing threshold level was selected the best one in same frequency, in both ears. Sensitivity and specificity of HHI were confirmed based on self awareness of hearing loss and PTAs at 1, 2, 4 kHz. Comparisons of two tests were measured by analyzing simple regression of correlation between PTAs of App_PTS and HHI scores. Sensitivity and specificity were 1.000 in both criteria. There was a statistically significant relationship between the PTAs_4 kHz and HHI (R-square = .951, p = .000). Hearing screening by questionnaire showed high correlation with smart phones based on application. Therefore, it can be useful as a hearing screening tool for individual life cycle using an user-friendly tool.