• Journal of Preventive Medicine and Public Health
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• v.31 no.2 s.61
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• pp.285-292
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• 1998

To investigate the effect of smoking on the hearing threshold, 1,887 adult male workers who visited health care center during the period 1 January 1996 - 31 July 1997 were selected. Air-conduction hearing threshold level, diastolic blood pressure(DBP), total cholesterol, fasting blood sugar(FBS), hematocrit and obesity were measured. The data on age, occupation, and smoking were collected. Air-conduction hearing threshold in smoker was significantly higher than non-smoker in categories of 250, 500, 1000 and 4000 Hz(p<0.05). Mean values of PTA-low, PTA-mid, and PTA-high in smoker were also significantly higher than non-smoker(p<0.05). In multiple regression analysis, smoking is likely to play a significant role after controlling age, occupation, DBP, FBS, total cholesterol, hematocrit, and obesity(p<0.05). The hearing threshold was significantly increased with increasing age(p<0.05), the manufacturing worker may have higher hearing threshold(p<0.05). The higher hematocrit and the more obese, the higher hearing threshold(p<0.05). However, DBP, total cholesterol and FBS were not significantly related with hearing threshold level. In conclusion, smoking was significantly related with the hearing threshold level in adult men.

• Journal of Audiology & Otology
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• v.23 no.3
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• pp.145-152
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• 2019

Background and Objectives: The present study aims to investigate whether the cochlear implant electrode array design affects the electrophysiological and psychophysical measures. Subjects and Methods: Eighty five ears were used as data in this retrospective study. They were divided into two groups by the electrode array design: lateral wall type (LW) and perimodiolar type (PM). The electrode site was divided into three regions (basal, medial, apical). The evoked compound action potential (ECAP) threshold, T level, C level, dynamic range (DR), and aided air conduction threshold were measured. Results: The ECAP threshold was lower for the PM than for the LW, and decreased as the electrode site was closer to the apical region. The T level was lower for the PM than for the LW, and was lower on the apical region than on the other regions. The C level on the basal region was lower for the PM than for the LW whereas the C level was lower on the apical region than on the other regions. The DRs on the apical region was greater for the PM than for the LW whereas the DR was narrower on the apical region than on the other regions. The aided air conduction threshold was not different for the electrode design and frequency. Conclusions: The current study would support the advantages of the PM over the LW in that the PM had the lower current level and greater DR, which could result in more localized neural stimulation and reduced power consumption.

• Korean Journal of Audiology
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• v.23 no.3
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• pp.145-152
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• 2019

Background and Objectives: The present study aims to investigate whether the cochlear implant electrode array design affects the electrophysiological and psychophysical measures. Subjects and Methods: Eighty five ears were used as data in this retrospective study. They were divided into two groups by the electrode array design: lateral wall type (LW) and perimodiolar type (PM). The electrode site was divided into three regions (basal, medial, apical). The evoked compound action potential (ECAP) threshold, T level, C level, dynamic range (DR), and aided air conduction threshold were measured. Results: The ECAP threshold was lower for the PM than for the LW, and decreased as the electrode site was closer to the apical region. The T level was lower for the PM than for the LW, and was lower on the apical region than on the other regions. The C level on the basal region was lower for the PM than for the LW whereas the C level was lower on the apical region than on the other regions. The DRs on the apical region was greater for the PM than for the LW whereas the DR was narrower on the apical region than on the other regions. The aided air conduction threshold was not different for the electrode design and frequency. Conclusions: The current study would support the advantages of the PM over the LW in that the PM had the lower current level and greater DR, which could result in more localized neural stimulation and reduced power consumption.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.623-629
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• 1997

This is cross-sectional study to evaluate a potential relationship between air conduction hearing threshold and blood viscosity in normal adult males(n=1677). We measured hearing threshold in frequency level at 500, 1000, 2000, 4000Hz by pure-tone audiometry and RBC profiles containing red cell number, hemoglobin, hematocrit. Blood viscosity are replaced by hematocrit that are one major factor of influencing blood viscosity. PTAs(pure-tone averages) are measured by hearing threshold averages level at 500Hz, 1000Hz, 2000Hz. Grades of PTAs(pure-tone averages) are divided three groups that are less then 10.0dB group, between 10.0-19.9dB group and excess 20.0dB. The results shows significant association among hematocrit, red cell number and hearing loss(age adjust by ANACOVA).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.2
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• pp.153-159
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• 2007

Usually equal noise exposure is considered to cause symmetrical hearing loss, but some screening audiometries of employees who were exposed to noise showed asymmetry. Therefore, this study was carried out to evaluate the distribution of asymmetrical hearing loss and the difference of air conduction level between left and right ear at the different frequencies (500, 1,000, 2,000, 3,000, 4,000, 6,000 Hz). Study subjects were 326 male employees who had participated in the noise-specific health examination from May to October, 2002. They were evaluated by otoscopic examination, pure tone audiometry and tympanometry. In all frequencies, hearing threshold level of left ear was worse than right ear. The mean interaural threshold differences between two ears were 0.83 dB at 500 Hz, 1.18 dB at 2,000 Hz, 2.29 dB at 3,000 Hz, 2.18 dB at 4,000 Hz, and statistically significant (p<0.05). The hearing loss of left ear was greater than right ear in occupationally noise-exposed workers. It is believed that left ear was more susceptible to noise damage than right ear

• Journal of Preventive Medicine and Public Health
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• v.7 no.1
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• pp.177-183
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• 1974

It is generally recognized that the environmental noise of the various working places thought to be the cause of hearing disturbance. This survey was carried out to evaluate the prevalence of noise-induced occupational bearing loss among the weavers of 39 textile industries in Taegu, Korea. For this survey, 432 male workers and 2,023 female workers were examined their hearing acuity by Individual pure tone threshold determination test(air conduction), from November, 1972, to January, 1973. Main findings were as follows : 1. The mean of noise intensity of the 54 weaving rooms was, in over all, $95.6{\pm}4.2dB\;(A),\;95.9{\pm}4.0dB\;(B)\;and\;96.2{\pm}3.9dB\;(C)$. 2. The mean hearing threshold levels by service years in the 4,000 Hz were intensively increased from 1st to 3rd year and slightly decreased. than that of 3rd year, from after 3rd to 5th year, after 5th year that increased slightly. 3. The mean hearing threshold levels by frequencies were highest in the 4,000 Hz(male: $25.0{\pm}11.3dB$, female: $22.0{\pm}10.2dB$) and followed by 6,000, 8,000 and 3,000 Hz. 4. The mean hearing threshold level of the 6,000 Hz (male: 17.0 dB. female: 17.9dB) was higher than that of 4,000Hz (male: 16.4 dB, female: 17.1dB) in tile 1st service year. 5. The mean hearing loss of examinees was $16.2{\pm}8.0dB$ in male and $15.4{\pm}7.8dB$ in female.

• Research in Community and Public Health Nursing
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• v.12 no.1
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• pp.125-141
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• 2001

The purpose of this study was to investigate the factors affecting hearing loss in adolescent's use of PCPs, and to give the basic data for adolescent's hearing conservation program development and prevention education against their hearing loss. This study was a descriptive research about three factors affecting hearing loss; the knowledge and attitude about noise, the perception of hearing loss and the hearing threshold. The subjects of this study were 383 students in two general high schools and two vocational high schools in Teagu. They have been using PCPs but with no current or past ear disease. This study was carried out from Sep. 1. 2000 to Oct. 24, 2000. The instrument used for the knowledge and attitude about noise was a questionnaire developed by Rhee. Kyung Yong and Yi. Kwan Hyung(1996). The instrument used for the perception of hearing loss was a Smith Hearing Screening Questionnaire. A Belton Model 112 Audiometer. air-conduction hearing test instrument. was used for the hearing threshold. Data was analysed by a SPSS/Win 10.0 program with frequency. percentage, t-test. ANOVA and pearson correlation. The results of this study were as follows; 1. The average of concern about hearing scored the highest $3.66{\pm}0.70$. The average of perceived susceptibility scored $2.64{\pm}0.85$ and the average of knowledge about noise scored $2.13{\pm}0.56$. The average of total knowledge and attitude about noise scored $2.82{\pm}0.46$. The average of discomfort of hearing loss($2.51{\pm}0.81$) scored higher than that fear of hearing loss($1.35{\pm}0.53$). The average of total perception of hearing loss scored $1.93{\pm}0.59$. The hearing threshold of the subjects scored the highest at 500Hz(Lt. $23.21{\pm}6.62$, Rt. $23.39{\pm}7.02$) and scored higher in order of 1000Hz, 2000Hz, 4000Hz and 8000Hz. 2. The knowledge and attitude about noise and the perception of hearing loss were both affected only by one important characteristic, which was general and vocational high schools. The knowledge and attitude about noise raked (t=5.258, p=0.000), and perception of hearing loss raked(t=2.241. p=0.026). However. several other important characteristics also impacted significantly on the knowledge and attitudes about noise. They included grade (t = 1. 987. p=0.048), father's education(F=2.745. p=0.043), marks(F=3.157, p=0.044), drinking(t=2.307, p=0.022) and smoking(t=2.587, p=0.010). The left hearing threshold differed significantly by sex at 1000Hz(t=5.175, p<0.001) and 8000Hz (t=3.334, p<0.01). According to general and vocational high schools (p<0.001), at 500Hz (t=-5.056), 1000Hz (t=-5.253), 2000Hz (t=-4.905), 4000Hz (t=-4.704) and 8000Hz (t=-5.204) significant differences were also shown. Marks were significant at 1000Hz (F=3.824, p<0.05) and drinking was found to be significant at 500Hz(t=2.203, p<0.05). The right hearing threshold differed significantly by sex at l000Hz(t=5.557. p<0.001). 4000Hz(t=2.234. p<0.05) and 8000Hz (t=2.730. p<0.01). According to general and vocational high schools(p<0.001) at 500Hz (t=-4.730), 1000Hz(t=-6.271). 2000Hz (t=-4.573). 4000Hz(t=-3.554) and 8000Hz (t=-3.405) significant differences were also shown. Grades impacted at 500Hz(t=2.201. p<0.05) and 4000Hz(t=2.511. p<0.05), while marks were significant at l000Hz(F=4.1l5. p<0.05) and drinking was significant at 500Hz(t=2.333. p<0.05). 3. The left hearing threshold in accordance with use of PCPs differed significantly at 2000Hz(F=2.996. p=0.03l) according to volume level and at 8000Hz(F=2.197. p=0.022) according to duration${\times}$hours per day. The right hearing threshold differed significantly at l000Hz(F=3.075. p=0.028) according to volume level and at 8000Hz(F=2.925. p=0.034) according to duration. 4. The knowledge and attitudes about noise showed a light positive correlation with the perception of hearing loss. A positive correlation was shown. as stated previously in all Hz, between the left hearing threshold and the right hearing threshold, especially the highest correlation at 2000Hz(r=0.761. p=0.000). This study has shown that the factors related to adolescent's use of PCPs are important as they impact significantly an adolescent's hearing. These results then indicate that in future, when designing a hearing conservation program and prevention education this data should be considered.

• Journal of Preventive Medicine and Public Health
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• v.30 no.2 s.57
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• pp.356-368
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• 1997

In effort to determine whether aircraft noise can have health effects such as hearing loss, hypertension and psychological stress, a total of 111 male professors and administrative officers working a college near a military airport in Korea(exposed group) and a total of 168 males and 112 females matched by age groups(control groups) were analyzed. Personal noise exposure and indoor and outdoor sound level of jet aircraft noise were measured at the exposed are3. And pure tone, air conduction test and measurement of blood pressure were given to the exposed(males) and matched control groups (males and females). BEPSI(Brief Encounter Psychological Instrument) and psychological response to aircraft noise were examined for the exposed group. The noise dosimetry results revealed time-weighted averages(TWAs) that ranged from 61 to 68 dBA. However the levels encountered during taking off jet airplanes reached 126 dBA for two half minutes time period. Th, audiometric, test showed that mean values of HTL(hearing threshold level) in exposed group at every frequency(500, 1,000, 2,000, 4,000, and 8,000 Hz were much lower than them of male and female control groups. And in old age groups, interaction of age and noise was observed at 8,000 Hz in both ears(p<0.05). Conclusively, aircraft noise does not appear to induce hearing loss directly in high frequency, but may decreased hearing threshold level by interaction of aging process and noise exposure. However, difference of mean values of exposed and control groups on blood pressure was not significantly. In psychological test, annoyance was the most severe psychological response to noise in exposed group, but mean value of BEPSI was not correlated with job duration in exposed group.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.38.1-38.10
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• 2023

Background: Hearing loss (HL) is linked to an elevated risk of cardiovascular diseases (CVDs). The pathogeneses of HL and CVD commonly involve inflammatory responses. Previous studies investigated elevated levels of inflammatory biomarkers in subjects with HL, however, their findings did not demonstrate statistical significance. In our cross-sectional and longitudinal study, we investigated the correlation between HL and increased high-sensitivity C-reactive protein (hsCRP) levels to determine how HL is associated with CVDs. Methods: We conducted a cross-sectional study with workers aged over 18 years who underwent health check-ups at our institution between 2012 and 2018 (n = 566,507), followed by conducting a longitudinal study of workers aged > 18 who underwent health checkups at least twice at our institution between 2012 and 2018 (n = 173,794). The definition of HL was as an average threshold of ≥ 20 dB in pure-tone air conduction at 0.5, 1.0, and 2.0 kHz in both ears. The incidence of increased hsCRP levels throughout the follow-up period was defined as a level exceeding 3 mg/L. Logistic regression and generalized estimating equations were performed to estimate the risk of increased hsCRP levels according to the occurrence of HL in groups stratified by age. Results: In the cross-sectional study, the multivariate-adjusted odds ratio (OR) was 1.17 (95% confidence interval [CI]: 1.02-1.34); the OR was 0.99 (95% CI: 0.80-1.22) in those under 40 and 1.28 (1.08-1.53) in those over 40. In the longitudinal study, the multivariable-adjusted OR was 1.05 (95% CI: 0.92-1.19); the OR was 1.10 (95% CI: 0.90-1.35) in those under 40 and 1.20 (1.01-1.43) in those over 40. Conclusions: This cross-sectional and longitudinal study identified an association between HL and increased hsCRP levels in workers aged over 40 years.

• Journal of Life Science
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• v.9 no.2
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• pp.136-145
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• 1999

The purpose of this study was to evaluate the effect of organic slovents and noise on hearing loss. We selected organic solvents exposed group of 32 cases, noise exposed group of 31 cases, both noise and solvent exposed group of 31 cases, and control group of 53 cases and studied the relation between exposure level of noise and organic solvents and degree of hearing loss. The results were as follows. The subjects under investigation were exposed to noise and organic solvents under threshold limit values and the amount of urinary hippuric acid excretion were also under biological exposure indices. In case of noise, both noise and organic solvents exposed group and noise exposed group were more exposed than organic solvents exposed group(p<0.05). When urinary hippuric acid excretion were concerned, both noise iud organic solvents exposed group and organic solvents exposed group showed higher values than noise exposed group(p<0.05). In comparison of mean auditory threshold values by frequency, on the air conduction test, both noise and organic solvents exposed group showed significantly higher hearing loss than noise exposed group in 500Hz of right ear, 500 and 2000Hz of left ear(p<0.05). Forty-three cases among 147 subjects were regarded as hearing loss group and average age(42.6years) of hearing loss group was higher than normal groups average age of 38.0 years. Urinary hippuric acid excretions of hearing loss group were significantly higher than normal group(p<0.05). Thirty-eight percent(12cases) of noise exposed group, 40.6 $\%$(13cases) of organic solvents exposed group, 51.6 $\%$(16cases) of both noise and organic solvents exposed group, and 3.8 $\%$(2cases) of unexposed group were regarded as hearing losers. Exposed groups showed higher incidence of hearing loss than unexposed group but there were no significant differences among the exposed groups. The variables showing significant correlation with hearing loss were age and the amount of hippuric acid in urinary excretion. When age were adjusted for the purpose of seeing the effects of hearing losses due to organic solvent, urinary excretion of hippuric acids was the only variable with significant correlation with hearing loss (p<0.05). When odds ratio to hearing loss between control and exposed groups was considered, noise exposed group showed 6.1 times (95 $\%$ CI: 3.3-8.7), organic solvents exposed group showed 7.4 times (95 $\%$ CI: 3.5-14.6) and both noise and organic solvents exposed group showed 17.2 times(95% CI: 5.6-31.8) higher values than unexposed group(p<0.01). Above results suggest that health screening test of hearing loss is also needed in organic solvents exposed workers.