• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.218-229
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• 2011

Companding algorithms have been used to enhance speech recognition in noise for cochlea implant users. The efficiency of using companding for digital hearing aid users is not yet validated. The purpose of this study is to evaluate the performance of the companding for digital hearing aid users in the various hearing loss cases. Using HeLPS, a hearing loss simulator, two different sensorinerual hearing loss conditions were simulated; mild gently sloping hearing loss(HL1) and moderate to steeply sloping hearing loss(HL2). In addition, a non-linear compression was simulated to compensate for hearing loss using national acoustic laboratories-non-linear version 1(NAL-NL1) in HeLPS. In companding, the following four different companding strategies were used changing Q values(q1, q2) of pre-filter(F filter) and post filter(G filter). Firstly, five IEEE sentences which were presented with speech-shaped noise at different SNRs(0, 5, 10, 15 dB) were processed by the companding. Secondly, the processed signals were applied to HeLPS. For comparison, signals which were not processed by companding were also applied to HeLPS. For the processed signals, log-likelihood ratio(LLR) and cepstral distance(CEP) were measured for evaluation of speech quality. Also, fourteen normal hearing listeners performed speech reception threshold(SRT) test for evaluation of speech intelligibility. As a result of this study, the processed signals with the companding and NAL-NL1 have performed better than that with only NAL-NL1 in the sensorineural hearing loss conditions. Moreover, the higher ratio of Q values showed better scores in LLR and CEP. In the SRT test, the processed signals with companding(SRT = -13.33 dB SPL) showed significantly better speech perception in noise than those processed using only NAL-NL1(SRT = -11.56 dB SPL).

• Health Policy and Management
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• v.28 no.2
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• pp.162-167
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• 2018

Background: In this research, we conducted an analysis to grasp the relationship between hearing and quality of life and to prepare effective troubleshooting. Methods: In this study, we analyzed using the data of the 6th term of the National Health and Nutrition Survey of the Disease Management Headquarters. And, out of 7,380 people, 3,598 adults over the age of 40 years who participated in the hearing test were selected as final research subjects and analyzed. Results: It was confirmed that the result of the analysis affects the quality of life based on hearing. The quality of life associated with hearing loss was unpleasant, motor ability, anxiety/depression, and everyday life affected in order of self management. And factors having an effect on the quality of life of the study subjects were found to be gender, elderly, unmarried, low hearing, low household income, absence of economic activity, and low teaching standards. Conclusion: The conclusion is that strengthening education for realistic management and prevention rather than treatment for unconditional hearing impairment will overcome low self esteem and loneliness and alleviate any uncomfortable life that people with hearing loss give. It is expected to be possible.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1976.06a
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• pp.85.1-85
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• 1976

Audiological evaluation was performed for 184 female weavers (351 ears), who were 18~25 years old and have been working under exposure of 103~105 ㏈a of machinary noise. With the duration of employment, they were divided into five groups; under 1 year, 1~2 years, 2~3 years, 3~4 years and over 4 years. The following results were obtained: 1. The incidence ;of noise induced hearing loss was 39.7% (36.2% of ears) and rapidly increased during first 1~2 years. 2. The average maximum hearing loss on the pure tone audiograms appeared at 4,000Hz with .about 40 ㏈ of hearing level. The average hearing level at high frequencies(3,000Hz~8,000Hz) showed below 25㏈ of hearing level in all groups and had the tendency to increase slightly with the duration of working, but the most of hearing losses developed during first one year except at 8,000Hz. 3. The average hearing level at speech frequencies was within normal range but the cases of hearing level over 25 ㏈ at 2,000Hz was 27.1%. 4. The cases with maximum hearing loss at 4,000Hz were 72.7%, but the cases of maximum hearing loss at the other frequencies (3,000Hz, 6,000Hz .and 8,000Hz) were also observed and they increased slightly in numbers with the duration of working. The noise induced hearing loss under the exposure of 103~105㏈a for 5 years, seemed to develope during first 1~2 years and there after slightly .increased hearing loss was showed but no remarkable changes were observed.

• Journal of Sasang Constitutional Medicine
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• v.23 no.3
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• pp.419-428
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• 2011

1. Objective: The aim of this study was to report significant improvement of tinnitus and insomnia after treatment with Cheongsimyeonja-tang in a Taeeumin patient with Idiopathic Sudden Sensorineural Hearing Loss(SSHL) that accompanied with Tinnitus. 2. Method: We measured the hearing recovery. For diagnosis on this case, pure tone audiometry was used. The degree of improvement was evaluated by Siegel's Criteria. Visual Analogue Scale(VAS) and Tinnitus Handicap Inventory(THI) were also used to assess tinnitus objectively. 3. Result: There was no improvement in pure tone audiometry by Siegel's Criteria. However, VAS score was decreased from 10 to 1 and THI score was also decreased from 74 to 48. 4. Conclusion: A patient with SSHL, who has little possibility of recovery of hearing loss, was treated with Cheongsimyeonja-tang in a short period and significant improvement in tinnitus and insomnia was observed. We consider that consistent treatment of Cheongsimyeonja-tang can contribute to improve the hearing loss.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.41-55
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• 1999

In order to evaluate the effects of knowledge, attitude and practice on noise-induced hearing loss or hearing threshold level, questionnaire survey was performed and hearing thresholds of 1 kHz and 4 kHz were measured on 1,040 subjects with workers exposed to noise, safety and health officers. industrial hygienists, analysts rind office workers. The results were as follows ; 1. The following 6 factors were obtained by factor analysis and factor rotation of 30 questionnaire of knowledge, attitude and practice about noise; knowledge of noise (F1), concern of hearing protective devices (F2), concern of noise induced hearing loss (F3), concern of noise level and hearing impairment (F4), concern of noise in workplace (F5) and recognition of noised-induced hearing loss (F6). 56.1% of variance was explained by 6 factors. 2. Significant variables influencing knowledge, attitude and practice about noise were education level and age in F1, personal protective devices (PPE) and education level in F2, age and education level in F3, education level, age and sex in F4, PPE, education level, age and work duration in F5, and work duration and PPE in F6. 3. Hearing thresholds of 4 kHz were significantly higher in workers exposed to noise than that of in the other subjects and tended to be higher in industrial hygienists, safety and health officers and analysts than that of the office workers. 4. Significant variables influencing hearing thresholds of 1 kHz were age, education level, F5 and F6 in workers exposed to noise, and F1 in industrial hygienists. 5. Significant variables influencing hearing thresholds of 4 kHz were age, F6, sex, work duration, F1, F5, F2 and F3 in workers exposed to noise, F1 and age in safety and health officers, and F6, sex and F4 in industrial hygienists. With the above results, it suggested that workers exposed to noise be needed the education of knowledge, attitude and practice about noise in hearing conservation program for the prevention of noise induced hearing loss. Also, it suggested that health managers in workplace be needed countermeasures to prevent hearing loss although they are intermittently exposed to noise.

• Journal of Biomedical Engineering Research
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• v.30 no.2
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• pp.169-178
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• 2009

In this study, we suggest Korean nonlinear fitting formula (KNFF) to maximize speech intelligibility for digital hearing aids based on NAL-NL1 (NAL-nonlinear, version 1). KNFF was derived from the same procedure which is used for deriving NAL-NL1. KNFF consider the long-term average speech spectrum of Korean instead of English because the frequency characteristic of Korean is different from that of English. New insertion gains of KNFF were derived using the SII (speech intelligibility index) program provided by ANSI. In addition, the insertion gains were modified to maximize the intelligibility of high frequency words. To verify effect of the new fitting gain, we performed speech discrimination test (SDT) and preference test using the hearing loss simulator from NOISH. In the SDT, a word set as test material consists of 50 1-syllable word generally used in hearing clinic. As a result of the test, in case of moderate hearing loss with severe loss on high frequency, the SDT scores of KNFF was more improved about 3.2% than NAL-NLl and about 6% in case of the sever hearing loss. Finally we have obtained the result that it was the effective way to increase gain of mid-high frequency bands and to decrease gain of low frequency bands in order to maximize speech intelligibility of Korean.

• Journal of agricultural medicine and community health
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• v.48 no.1
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• pp.41-49
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• 2023

Objectives: To obtain audiologic basic data to diagnose the noise induced hearing loss of workers in fisheries. Methods: The charts of the referred fishermen with noise induced hearing loss from November 2022 to February 2023 at a general hospital were retrospectively reviewed. Pure tone audiometry, speech audiometry, auditory brainstem response test and auditory steady state response test were conducted. Results: All of them were men over 60 years of age, and the average duration of exposure to noise was 38.9 ± 10.8 years, and the average symptom duration of hearing loss was 13.4 ± 4.3 years. Although the hearing thresholds in the high frequencies were higher than thresholds in the low frequencies, the audiogram showed a down-sloping pattern without rebound at 8 kHz. 10.5% of the cases had thresholds greater than 75 dB in high frequencies, but 57.9% had thresholds greater than 40 dB in low frequencies. Other hearing test results of fishermen were similar to those of general noise-induced hearing loss. Conclusions: Although the fishermen were exposed to noise for a long time, they recognized hearing loss late. The hearing threshold in lower frequencies of the fishermen was higher than expected. Further studies will be needed to analyze the audiologic characteristics of noise-induced hearing loss of the fishermen after confirming noise exposure by conducting a survey on the working environment, such as the noise level and working hours.

• Journal of Korean Public Health Nursing
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• v.25 no.2
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• pp.197-208
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• 2011

Background: This study investigated the hearing status in Korean adults according to data from the Korea National Health and Nutrition Examination Survey 2009. Methods: The data of 3,479 adults(${\geq}20$ years, 1,492 men, 1,987 women) collected by the Korean Center for Disease Control was analyzed using ${\chi}^2$-test and logistic regression. Results: Differences in hearing loss according to individual factors were evident by follows gender, region, education status, economic status, current smoking and recognition of stress. Differences in - hearing loss according to ear related factors were evident subjective hearing status, experience of tinnitus, prevalence of chronic otitis media, and tympanomembrane abnormality. Conclusion: Hearing-related disorders can cause many social problems. This study investigated a representative cross-section of Koreans to determine the hearing status. The study was limited in that the risk factors of hearing loss were not identified. It is also recommended that a program be developed that can help control the variables identified in this study along with follow-up studies to verify the model.

• Journal of Preventive Medicine and Public Health
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• v.26 no.3 s.43
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• pp.371-386
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• 1993

This study was carried out to evaluate diagnostic criteria of noise-induced hearing loss (NIHL) among-workers in an iron foundry. Of 1,093 workers under the observation of noise-specific health examination, 184 workers were selected by way of first and second screening audiometric examination. A questionnaire survey, otological examinations, Rinne test and audiometric test were performed and the results were as follows ; The degree of hearing impairment in the left ear was more severe than in the right ear (p<0.05). The difference between hearing threshold of the first and the second hearing test at 1,000 Hz was about 5 dB with a narrow range of deviations while the difference at 4,000 Hz was about -7 dB with a wide range. Of the total study workers, 84.8% were tested within 15 hours away from noise exposure, and the rest after 16 hours. This study has identified that mean hearing loss at 4,000 Hz showed a significant statistical difference among the two study groups while mean hearing loss by 4-divided classification did not. The same phenomena were observed between the group with and without tinnitus and between the group with and without difficulty in hearing (p<0.05). Among 184 workers, 10 workers (5.4%) diagnosed as NIHL by old diagnostic criteria in contrast to 150 workers diagnosed as NIHL by the new diagnostic criteria. There was a significant difference between the two groups in the average hearing loss at 4,000 Hz and 4-divided classification (p<0.01), but there were no significant differences in age, the duration of employment, blood pressure and the duration wearing the personal hearing protector (p>0.05). If we apply Early Loss Index (ELI) method, some workers in younger age group diagnosed as NIHL by the new diagnostic criteria were fallen into within the normal range. In the mean time older age group show reverse results in contrast to the above finding. It is too early to confirm the value of the usage of the new diagnostic criteria in hearing examination. Further study is called for to verify the value of this criteria.

• Journal of Audiology & Otology
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• v.25 no.1
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• pp.27-35
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• 2021

Background and Objectives: This study aimed to evaluate the clinical features and the clinical factors associated with prognosis of sudden sensorineural hearing loss (SSNHL) in diabetic patients. Subjects and Methods: Forty-nine diabetic with unilateral SSNHL were retrospectively included. All patients received systemic high dose steroid therapy within one month after onset and had more than one month of follow-up audiogram. The basic characteristics of the patients, initial and follow-up audiograms, laboratory data, and methods of steroid treatment were collected. Results: Compared to reference values in healthy subjects, 79%, 55%, and 45% of the patients had higher values of mean neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and lymphocyte-monocyte ratio (LMR), respectively. Older patients had significantly less degree of hearing loss, but they also had significantly worse hearing thresholds in the unaffected ear. After steroid treatment, less than half patients (47%) showed hearing recovery. Simultaneous intratympanic dexamethasone (ITD) injections with systemic steroid did not confer an additional hearing gain or an earlier recovery rate in diabetic patients with SSNHL. In the multivariate analysis, initial hearing thresholds of affected ear and timing of steroid treatment were significantly associated with hearing prognosis in diabetic patients with SSNHL. Conclusions: Diabetic patients with SSNHL tended to have increased NLR, LMR, and PLR, which are reported to be associated with microvascular angiopathy. Simultaneous ITD injections to improve hearing recovery in diabetic patients with SSNHL seems unnecessary.