• The Journal of the Acoustical Society of Korea
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• v.35 no.1
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• pp.24-34
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• 2016

The popularity of personal listening devices(PLDs) has increased over past years, especially, in adolescents. Overuses and missuses of PLDs could be the cause of noise-induced hearing loss (NIHL). The purposes of this study were (1) to survey middle school students' habits using PLDs, knowledge of hearing loss and attitude of hearing protection and (2) to develope a questionnaire for assessment of habits using PLDs, knowledge of hearing loss and attitude of hearing protection in adolescents. The 41-item questionnaire was designed and used to survey middle school students' habits using PLDs, knowledge of hearing loss and attitude of hearing protection. A total of 404 middle school students aged 14-15 years participated in the survey. Most of the students were found to use PLDs soundly. However, 30 % of students used PLDs for more than 3 hours a day. Also, almost all of the students did not understand knowledge of the causes of hearing loss, but showed interests in hearing protection. However, some students had insufficient understanding of the causes of hearing loss and the needs of hearing protection. The results suggest that the development of programs for adolescents' hearing health is needed.

• Journal of Biomedical Engineering Research
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• v.27 no.6
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• pp.376-383
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• 2006

Noise induced hearing loss (NIHS), the well-known occupational disease, is caused by continuous excessive noise. The prevention of NIHS is very important, because it is unrecoverable. There are some kinds of hearing protection device (HPD), and those are effective in preventing NIHS. But workers in noisy environment often resist to wearing them. Because they are ready - made products, so workers feel uncomfortable to wear. Also, they didn't maintain the conversation frequency range, so workers are hard to communicate in wearing them. To prevent hearing loss effectively, it is important that workers keep wearing HPD. Therefore, a HPD is needed to be comfortable to wear and be effective not only in hearing protection but also in preserving communication ability. So we proposed a custom - made hearing protection device in which a small acoustic filter is inserted. We designed several kinds of small acoustic filters and carried out some acoustic experiments for measuring characteristics of filters. We confirmed that acoustic transmission characteristic can be adjusted from experimental results using designed small acoustic filters. And we researched for the actual efficiency of a new developed custom - made hearing protection device using a small size acoustic filter. Also, we found out that workers are more satisfied with the new development than a former protection device from a workers' response.

• Journal of Preventive Medicine and Public Health
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• v.20 no.2 s.22
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• pp.205-214
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• 1987

For the purpose of evaluating the effect of noise induced hearing loss on the blood pressure, a cross-sectional study was conducted in 481 manufacturing industrial workers in Pusan area consisted of 275 workers from noisier plant (over 90 dB(A), high exposed group) and 206 workers from less noisy plant (below 85 dB(A), low exposed group) from April to Decepmber in 1985. The summarized results were as follows; 1) The degree of hearing loss according to the audible frequency was most notable in 4,000 Hz. 2) The prevalence of hypertension was 14.8% in total examined subjects. And also in 40 dB(A) hearing lost workers, there was no significant difference between high exposed group as 15.5% and low exposed group as 15.8%. 3) In 3 models analyzed by multiple regression technique to obtain the complexed extents of risk factors related to the diastolic blood pressure, especially model III which contain age, body mass index, smoking, alcohol and family history of hypertension, duration of work, noise exposure level and degree of hearing loss in high exposed group was most remarkable compared to the others. 4) The most potential predictor related to the diastolic pressure in high exposed group was the degree of hearing loss. And the next were body mass index, familial history of hypertension and age in order. But in the case of low exposed group, the potential predictors were body mass index, age and familial history of hypertension.

• Journal of Preventive Medicine and Public Health
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• v.30 no.4 s.59
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• pp.815-829
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• 1997

This study was performed to assist the employer to establish the effective program for hearing conservation of noisy industry. The study subjects were health care managers of an industry and the study industries were devided into two groups(Group I, 37 industries; have the workers diagnosed as noise-induced hearing loss, Group II, 41 industries; not have the workers diagnosed as noise-induced hearing loss) and the question method carried out through the face to face interview. The contents of questionnaire for OSHA's hearing conservation program(HCP) consisted of seven components: 5 questions of monitoring of employee noise exposures(component 1), 6 questions of the institution of engineering, work practice, and administrative controls for excessive noise(component 2), 8 questions of the provision of each overexposed employee with an individually fitted hearing protector with an adequate noise reduction rating(component 3), 14 questions of employee training and education regarding noise hazards and protection measures(component 4), 9 questions of baseline and annual audiometry(component 5), 3 questions of procedures for preventing further occupational hearning loss by an employee whenever such an event has been identified(component 6), and 1 question of recording keeping(component 7), thus total numbers of questions was 46. The numbers of statistially significant difference(p<0.05) between two groups were 2(25.0%) among 8 questions of component 3, 10(71.4%) among 14 questions of component 4, 3(33.3%) among 8 questions of component 5, 2(6.7%) among 3 questions of component 6, and 17(37.0%) among total 46 questions of questionnaire. Above results showed that the level of HCP acceptance in group I was lower than in group II. Thus employer's understanding about HCP should be precede for the effective hearing conservation program of employee and the adequate hearing protector, training and education, baseline and annual audiometry, and procedures for preventing further occupational hearning loss for hearing conservation would be more emphasized.

• Journal of Preventive Medicine and Public Health
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• v.22 no.3 s.27
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• pp.337-354
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• 1989

In order to evaluate the noisy environment and hearing loss of workers served in noisy working environment, the author investigated 212 manufacturing industries located in Ulsan Industrial District that could be observed for 3 successive years from 1986 to 1988. The obtained results were as follows: 1. There was increased tendency in the number of workers served in noisy working environment and that of examined of hearing loss for three years. 2. In the noise level of working environment, the number of industries less than 89dB(A) was increased every year, while more than 90dB(A) was in decreasing tendency. 3. Mean hearing loss by frequency was the most prominent in 4,000Hz, the level of hearing loss was in increasing tendency yearly, and that of left eat was higher than right ear in almost all type of industry. 4. In 1986, the level of hearing loss by type of industry was highest in manufacture of electric and electronic, and followed by paper and plywood, and metal products in right ear: that was in the order of manufacture of electric and electronic, metal products and textile products in left ear. In 1987, that was in the order of manufacture of metal products, machinery and others in right ear, and metal products, machinery and food stuff in left ear in 1988, manufacture of others, food stuff and machinery in both ear. 5. In hearing loss by service duration, right ear of 5-9 years group was higher than that of less than 5 years in 1987, whereas in 1988, the longer in service duration, the higher in the level of hearing loss in both ear. 6. In 1986, 1987 and 1988, the prevalence rate of noise-induced hearing loss were showed increasing tendency as 0.4% ,0.8% and 1.5% , respectively, and manufacture of textile products was highest(1.0%) in 1986, machinery(1.2%) in 1987 and others(2.8%) in 1988. 7. The proportion of grade E in early loss index were 76.1% (1986), 78.2% (1987) and 80.5% (1988) in left ear, 75.9% (1986), 76.4% (1987) and 75.9% (1988) in right ear.

• Journal of Korean society of Dental Hygiene
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• v.15 no.1
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• pp.11-17
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• 2015

Objectives: The purpose of the study is to investigate the relationship between noise awareness, hearing ability, and dental hygiene performance in dental hygienists. Methods: The subjects were 234 dental hygienists in Seoul, Gyeonggi-do, and Incheon. The questionnaire consisted of 3 questions of general characteristics of the subjects, 1 question of noise awareness, 3 questions of hearing ability, 5 questions of dental hygiene performance, 1 question of noise reduction necessity, and 2 questions of noise control. Noise awareness, dental hygiene performance, and noise reduction necessity were measured by Likert 5 scale. Cronbach's alpha was 0.825 in dental hygiene performance reliability. Results: There was a significant difference in noise recognition by age(p<0.01) and working career(p<0.05). Those who pumped up the higher TV volume accounted for 31.6% and 3.0% had hearing impairment in the regular health checkup. 3.4% of the respondents complained of hearing loss, ear fluid, and equilibrium problem diagnosed by the doctors. The relationship between the type of workplace environment and task performance showed a significant difference. Those who work in the dental hospitals had high score of 3.43, while those who work in dental clinics had 3.20(p<0.05). The increased level of noise recognition affected the task performance and it is necessary to reduce the noise level. More try must be focused on the noise exposure prevention. Conclusions: In order to reduce the problems due to noise and improve their quality of life, it is necessary to change the noise recognition in the work place.

• Safety and Health at Work
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• v.15 no.2
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• pp.220-227
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• 2024

Background: Though the artificial neural network (ANN) technique has been used to predict noise-induced hearing loss (NIHL), the established prediction models have primarily relied on cross-sectional datasets, and hence, they may not comprehensively capture the chronic nature of NIHL as a disease linked to long-term noise exposure among workers. Methods: A comprehensive dataset was utilized, encompassing eight-year longitudinal personal hearing threshold levels (HTLs) as well as information on seven personal variables and two environmental variables to establish NIHL predicting models through the ANN technique. Three subdatasets were extracted from the afirementioned comprehensive dataset to assess the advantages of the present study in NIHL predictions. Results: The dataset was gathered from 170 workers employed in a steel-making industry, with a median cumulative noise exposure and HTL of 88.40 dBA-year and 19.58 dB, respectively. Utilizing the longitudinal dataset demonstrated superior prediction capabilities compared to cross-sectional datasets. Incorporating the more comprehensive dataset led to improved NIHL predictions, particularly when considering variables such as noise pattern and use of personal protective equipment. Despite fluctuations observed in the measured HTLs, the ANN predicting models consistently revealed a discernible trend. Conclusions: A consistent correlation was observed between the measured HTLs and the results obtained from the predicting models. However, it is essential to exercise caution when utilizing the model-predicted NIHLs for individual workers due to inherent personal fluctuations in HTLs. Nonetheless, these ANN models can serve as a valuable reference for the industry in effectively managing its hearing conservation program.

• 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.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.1064-1069
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• 1994

In order to realize the function of human interface of telecommunications whose objective is to interchange useful information among persons, we developed a bone conduction telephone with which hearing impaired persons with conductive or noise-induced hearing loss and presbycusis can communicate with each other without any other additional devices such as hearing aids. The bone conduction telephone we developed has chatacteristics as follows : (i) a hearing impaired person and a normal hearing person can communicate by bone and air conduction hearings, respectively, using only this telephone set because, as its receiver, it uses a bone conduction vibrator with which we can realize such function with the voice coil and damper of a small speaker unit, the vibrating plate, etc., (ii) it has tone control function compensating hearing losses of hearing impaired persons according to their hearing loss/frequency chatacteristics. Using the tone control function together with a received volume control, it has the received volume range of 20dB in loudness rating; and (iii) it has the function of three emergency calls and a bell lamp as the visual display of a received call.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.913-919
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• 2004

Mitochondrial DNA mutations have been reported in recent years in association with sensorineural hering loss. The purpose of this study is to identify the association between the noise-induced sensorineural hearing loss and the A to G mutation at nucleotide 3243, 1555, 7445 of mitochondrial DNA. Study subjects were established by history and chart review, and audiological and clinical data were obtained. Blood was sampled from 214 normal controls, 102 noise-induced hearing loss, and 28 sensorineural hearing loss. The DNA of these individuals were extracted, and mitochondrial DNA fragments were analyzed by polymerase chain reaction. Subsequently, the coding sequence of mitochondrial DNA 3243, 1555, 7445 were sequenced, and compared to the normal sequence, and all sequence variations were analyzed by restriction enzymes. Mitochondrial DNA mutations $(3243A{\rightarrow}G,\;1555A{\rightarrow}4G,\;7445A{\rightarrow}G)$ were not detected by polymerase chain reactions in any patients with noise-induced hearing loss, sensorineural hearing loss, and normal controls. The DNA sequencing of PCR products did not revealed an A to G substitution at nucleotide 3243, 1555, 7445 of mitochondrial DNA. The noise-induced sensorineural hearing loss was not associated with mitochondrial DNA mutation $(3243A{\rightarrow}G,\;1555A{\rightarrow}4G,\;7445A{\rightarrow}G)$.