• The Journal of the Acoustical Society of Korea
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• v.31 no.5
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• pp.273-279
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• 2012

In this thesis, a nonlinear compression fitting method was studied for each frequency channel of a 64 channel digital hearing aid. Unlike conventional fitting formula method done from the result of the hearing loss test, the present fitting method uses the auditory threshold of sound pressure measured near the tympanic membrane while ITE (In-The-Ear) hearing aid is fitted into the user's ear canal. Also, the spectral distribution of the voice sound pressure was used for realizing of output sound pressure compression curves against input sound pressure level. Theoretical research results of FFT-iFFT compression algorithm has been evaluated by experimental gain measurements at each different input sound pressure level 50 dB, 70 dB, 90 dB respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.12
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• pp.1604-1610
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• 2018

The speech recognition service is used as an ancillary means of communication by converting and visualizing the speaker's voice into text to the hearing impaired persons. However, in open environments such as classrooms and conference rooms it is difficult to provide speech recognition service to many hearing impaired persons. For this, a method is needed to efficiently provide it according to the surrounding environment. In this paper, we propose a system that recognizes the speaker's voice and transmits the converted text to many hearing impaired persons as messages. The proposed system uses the MQTT protocol to deliver messages to many users at the same time. The end-to-end delay was measured to confirm the service delay of the proposed system according to the QoS level setting of the MQTT protocol. As a result of the measurement, the delay between the most reliable Qos level 2 and 0 is 111ms, confirming that it does not have a great influence on conversation recognition.

• Journal of Audiology & Otology
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• v.25 no.4
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• pp.171-177
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• 2021

Background and Objectives: The purpose of the present study was to validate the performance and diagnostic efficacy of the Korean digits-in-noise (K-DIN) test in comparison to the Korean speech perception-in-noise (K-SPIN) test, which is the representative speech-in-noise test in clinical practice. Subjects and Methods: Twenty-seven subjects (15 normal-hearing and 12 hearing-impaired listeners) participated. The recorded Korean 0-9 digits were used to form quasirandom digit triplets; 50 target digit triplets were presented at the most comfortable level of each subject while presenting speech-shaped background noise at various levels of signal-to-noise ratios (-12.5, -10, -5, or +5 dB). Subjects were then instructed to listen to both target and noise masker unilaterally and bilaterally through a headphone. K-SPIN test was also conducted using the same procedure as the K-DIN. After calculating their percent correct responses, K-DIN and K-SPIN results were compared using a Pearson-correlation test. Results: Results showed a statistically significant correlation between K-DIN and K-SPIN in all hearing conditions (left: r=0.814, p<0.001; right: r=0.788, p<0.001; bilateral: r=0.727, p<0.001). Moreover, the K-DIN test achieved better testing efficacy, shorter average listening time (5 min vs. 30 min), and easier performance of task according to participants' qualitative reports than the K-SPIN test. Conclusions: In this study, the Korean version of digit triplet test was validated in both normal-hearing and hearing-impaired listeners. The findings suggest that the K-DIN test can be used as a simple and time-efficient hearing-in-noise test in audiology clinics in Korea.

• Korean Journal of Audiology
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• v.25 no.4
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• pp.171-177
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• 2021

Background and Objectives: The purpose of the present study was to validate the performance and diagnostic efficacy of the Korean digits-in-noise (K-DIN) test in comparison to the Korean speech perception-in-noise (K-SPIN) test, which is the representative speech-in-noise test in clinical practice. Subjects and Methods: Twenty-seven subjects (15 normal-hearing and 12 hearing-impaired listeners) participated. The recorded Korean 0-9 digits were used to form quasirandom digit triplets; 50 target digit triplets were presented at the most comfortable level of each subject while presenting speech-shaped background noise at various levels of signal-to-noise ratios (-12.5, -10, -5, or +5 dB). Subjects were then instructed to listen to both target and noise masker unilaterally and bilaterally through a headphone. K-SPIN test was also conducted using the same procedure as the K-DIN. After calculating their percent correct responses, K-DIN and K-SPIN results were compared using a Pearson-correlation test. Results: Results showed a statistically significant correlation between K-DIN and K-SPIN in all hearing conditions (left: r=0.814, p<0.001; right: r=0.788, p<0.001; bilateral: r=0.727, p<0.001). Moreover, the K-DIN test achieved better testing efficacy, shorter average listening time (5 min vs. 30 min), and easier performance of task according to participants' qualitative reports than the K-SPIN test. Conclusions: In this study, the Korean version of digit triplet test was validated in both normal-hearing and hearing-impaired listeners. The findings suggest that the K-DIN test can be used as a simple and time-efficient hearing-in-noise test in audiology clinics in Korea.

• Journal of the Korea Convergence Society
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• v.12 no.10
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• pp.97-104
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• 2021

The purpose of the study was to investigate whether there are differences in confrontation naming ability, generative naming ability, hearing handicap, and depression in community-dwelling elderly by age group, and whether there is any correlation among them, and to find out what factors explain the two naming abilities (confront and generative) of the elderly. Sixty-five community-dwelling elderly people participated: 65~74 years were classified into young-old; 75~84 years into old-old; and 85 years and over into oldest-old. K-BNT-15 for the confrontation naming ability, animal naming test for the generative naming ability, K-HHIE for the subjective hearing handicap, and GDS for the subjective depression were administered. First, there was a statistically significant difference in confrontation naming and depression levels according to age groups. Second, there was a positive correlation between chronological age and subjective depression level and between subjective hearing handicap level and subjective depression level, and a negative correlation between education level and subjective depression level. Third, the confrontation naming score was explained by age, and the generative naming score was explained by subjective depression level. The results show that naming abilities, subjective hearing handicap, and subjective depression level are not simply the result of normal aging and that a convergence approach is needed in various fields to solve the issue.

• Journal of Preventive Medicine and Public Health
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• v.27 no.2 s.46
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• pp.286-298
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• 1994

For the purpose of presenting the basic data for the establishment of control measures on the long-term noise exposed workers, this study was carried out on the relationship between personal noise exposed dose and hearing loss on the 67 male workers whose hearing threshold had exceeded 40 dB in 4,000 Hz, from 1990 to 1992. Conclusively, the level of hearing loss was significantly related to personal noise exposed dose in follow-up period. We considered that personal noise exposed dose which was measured by the personal noise dosemeter was more efficient rather than the noise level of workplace for the evaluating the long-term change of hearing acuity. And although in the case of not-diagnosed as noise induced hearing loss. it was suspected that the active control programs such as improvement of noisy environment or early transfer to proper workplace were needed on the workers who exposed with over 90 dB in personal noise exposed dose.

• Journal of Yeungnam Medical Science
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• v.36 no.2
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• pp.141-147
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• 2019

Background: The present study aimed to evaluate the clinical association between cadmium exposure and hearing impairment among the Korean population. Methods: This retrospective cross-sectional study used the data obtained from the Korean National Health and Nutrition Examination Survey were used for our study. Finally, 3,228 participants were included in our study, which were then divided into quartiles based on their blood cadmium levels: first quartile (1Q), second quartile (2Q), third quartile (3Q), and fourth quartile (4Q) groups. The hearing thresholds were measured using an automatic audiometer at 0.5, 1, 2, 3, 4, and 6 kHz. Hearing loss (HL) was defined as >25 dB average hearing threshold (AHT). Results: All the groups had 807 participants each. The area under the receiver operating characteristic curves of cadmium level for HL were 0.634 (95% confidence interval [CI], 0.621-0.646). The participants in the 4Q group had higher Low/Mid-Freq, High-Freq, and AHT values than those in the other groups in the multivariate analysis after adjusting for confounding factors. The logistic regression showed that the OR for HL per $1{\mu}g/L$ increase in cadmium was 1.25 (95% CI, 1.09-1.44; p=0.002) on the multivariate analysis. Moreover, the multivariate logistic regression analyses revealed that the participants in the 4Q group exhibited a 1.59-, 1.38-, and 1.41-fold higher odds for HL than those in the 1Q, 2Q, and 3Q groups, respectively. Conclusion: High cadmium level quartile was associated with increased hearing thresholds and HL among the Korean adult population.

• Speech Sciences
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• v.11 no.3
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• pp.175-180
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• 2004

In case of the hearing impairment with tinnitus and increased sound sensitivity, it is known that the patients tend to appeal the psychologically oriented social handicap rather than communication disability. The audiologist who is responsible for such patients in aural rehabilitation should pay special attention to the counseling techniques including tinnitus retain therapy (TRT), ear protector, noise generator, or specific acoustic training based on close cooperation and rapport. And then the audiologist should try to lessen their reaction to the tinnitus by using a hearing aid. This therapies tries to focus not a. total approach but a treatment to lessen the severity of tinnitus. This paper as a case report that a unilateral sharply slopped sensorineural hearing impaired person with tinnitus and increased sound sensitivity by using four channel digital signal processing (DSP) hearing aid with programming increment at low level (PILL).

• Journal of the Ergonomics Society of Korea
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• v.15 no.1
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• pp.79-90
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• 1996

A research project was conducted to assess the levels of noise exposed to "Noraebang" users and potential hazards to noise-induced hearing loss due to commercial Noraebang noise. A two-way, mixed-factors factorial design was employed for the experiment using independent variables of "noise source" (no- singer, 1-singer, and 2-singer conditions) and "music type" (Trot, Ballad, and Rock music) with 18 normal hearing subjects. Each singer group sang 5 popular songs of each music type in each signing condition, whereas background music was just played for the no-singer condition. For each music played/sung, equivalent continuous sound pressure levels and maximum sound pressure levels were measured for data analysis purposes. Pure-tone audiometry was applied for measuring subjects' hearing threshold levels before and after exposure to Noraebgang noise. The statistical analyses indicate that average continuous noise levels due to Noraebang leisure environment were very serious, especially when two people were singing (higher than 95 dBA). Furthermore, maximum noise levels often exceeded the OSHA's non-premissible 115 dBA level. Worse yet, hearing loss assessment implies that Noraebang facilities may pose a serious threat to noise-induced hearing loss, based on 6-8 dB loss at 125 Hz and 8 dB loss at 4000 Hz after about 1-hour Noraebang noise exposure.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.34 no.3
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• pp.102-111
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• 2021

Objectives : The purpose of this study is to report the case of a presbycusis patient whose hearing had improved. Methods : A 81-year-old male diagnosed with presbycusis were treated with Korean medical interventions (acupuncture combined with electromagnetic stimulation and pharmacoacupuncture) and Threshold sound conditioning(TSC) for 3 months. Pure tone audiometry(PTA) was performed for the evaluation. Results : The patient's hearing was improved from moderate to mild level according to the Classification of Hearing Loss(International Organization for Standardization, 1969). The average hearing were improved from 40.5 dB to 32.7dB on the left side, 46.9dB to 34.1dB on the right side. Conclusions : We observed an improvement in a presbycusis patient's hearing and hereby suggest the possibility of Korean medical treatment and TSC's ameliorating effect on sensorineural hearing loss as well as prebyscusis.