• The Journal of the Acoustical Society of Korea
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• v.31 no.5
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• pp.298-308
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• 2012

This study was designed to examine the phoneme recognition errors of hearing-impaired (HI) listeners on a consonant-by-consonant basis, to show (1) how each HI ear perceives individual consonants differently and (2) how standard clinical measurements (i.e., using a tone and word) fail to predict these differences. Sixteen English consonant-vowel (CV) syllables of six signal-to-noise ratios in speech-weighted noise were presented at the most comfortable level for ears with mild-to-moderate sensorineural hearing loss. The findings were as follows: (1) individual HI listeners with a symmetrical pure-tone threshold showed different consonant-loss profiles (CLPs) (i.e., over a set of the 16 English consonants, the likelihood of misperceiving each consonant) in right and left ears. (2) A similar result was found across subjects. Paired ears of different HI individuals with identical pure-tone threshold presented different CLPs in one ear to the other. (3) Paired HI ears having the same averaged consonant score demonstrated completely different CLPs. We conclude that the standard clinical measurements are limited in their ability to predict the extent to which speech perception is degraded in HI ears, and thus they are a necessary, but not a sufficient measurement for HI speech perception. This suggests that the CV measurement would be a useful clinical tool.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.435-438
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• 2005

Until now, a home appliance mostly has revealed physical quantities created by the standpoint of engineers, by using the A-weighted sound pressure level and the sound power. It is, however, obviously impossible to characterize a complex sound with a single number. Many parameters must be considered. In addition to loudness, we must take into account frequency and amplitude variation over time, spectral balance, tonality, and many other attributes. Thus, in this research, the general tendency of consumer psychology was investigated for the refrigerator's sound. The noise from the refrigerator was evaluated by not only the simple sound pressure levels but also the consumer's sense of hearing. And also, in order to improve the quality of sound through the design change, the consumer's evaluation was analysed and related to the engineering quantities. With the several design changes, finally the most silence refrigerator in the world was developed with considering the consumer's hearing of sense.

• 재활복지
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• v.21 no.2
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• pp.63-88
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• 2017

This study evaluated the actual status of special needs of the hearing-impaired person for disaster response. The analysis revealed a significant level of unmet needs in disaster response for hearing-impaired person. The 5 special needs in disaster response include: 1) communication needs, which involve securing the means to make an emergency rescue request and communicating information during the rescue process; 2) transportation needs, which indicate the effective evacuation capacity and the level of training; 3) medical needs, which address the degree of preparedness for physical and mental emergency measures and the delivery of health information for rescue and first aid process; 4) maintaining functional independence needs, which refer to the level of self-preparedness to minimize damage in disaster situations, and; 5) supervision needs, which correspond to a personalized support system provided to disaster-vulnerable groups.

• Safety and Health at Work
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• v.2 no.4
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• pp.348-354
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• 2011

Objectives: This cross-sectional study was performed in the Dental School of Prince of Songkla University to ascertain noise exposure of dentists, dental assistants, and laboratory technicians. A noise spectral analysis was taken to illustrate the spectra of dental devices. Methods: A noise evaluation was performed to measure the noise level at dental clinics and one dental laboratory from May to December 2010. Noise spectral data of dental devices were taken during dental practices at the dental services clinic and at the dental laboratory. A noise dosimeter was set following the Occupational Safety and Health Administration criteria and then attached to the subjects' collar to record personal noise dose exposure during working periods. Results: The peaks of the noise spectrum of dental instruments were at 1,000, 4,000, and 8,000 Hz which depended on the type of instrument. The differences in working areas and job positions had an influence on the level of noise exposure (p < 0.01). Noise measurement in the personal hearing zone found that the laboratory technicians were exposed to the highest impulsive noise levels (137.1 dBC). The dentists and dental assistants who worked at a pedodontic clinic had the highest percent noise dose (4.60 ${\pm}$ 3.59%). In the working areas, the 8-hour time-weighted average of noise levels ranged between 49.7-58.1 dBA while the noisiest working area was the dental laboratory. Conclusion: Dental personnel are exposed to noise intensities lower than occupational exposure limits. Therefore, these dental personnel may not experience a noise-induced hearing loss.

• Journal of Audiology & Otology
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• v.25 no.1
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• pp.14-21
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• 2021

Background and Objectives: There is growing interest in the use of the Level-specific (LS) CE-Chirp^® stimulus in auditory brainstem response (ABR) due to its ability to produce prominent ABR waves with robust amplitudes. There are no known studies that investigate the test-retest reliability of the ABR to the LS CE-Chirp^® stimulus. The present study aims to investigate the test-retest reliability of the ABR to the LS CE-Chirp^® stimulus and compare its reliability with the ABR to standard click stimulus at multiple intensity levels in normal-hearing adults. Subjects and Methods: Eleven normal-hearing adults participated. The ABR test was repeated twice in the same clinical session and conducted again in another session. The ABR was acquired using both the click and LS CE-Chirp^® stimuli at 4 presentation levels (80, 60, 40, and 20 dBnHL). Only the right ear was tested using the ipsilateral electrode montage. The reliability of the ABR findings (amplitudes and latencies) to the click and LS CE-Chirp^® stimuli within the same clinical session and between the two clinical sessions was calculated using an intra-class correlation coefficient analysis (ICC). Results: The results showed a significant correlation of the ABR findings (amplitude and latencies) to both stimuli within the same session and between the clinical sessions. The ICC values ranged from moderate to excellent. Conclusions: The ABR results from both the LS CE-Chirp^® and click stimuli were consistent and reliable over the two clinical sessions suggesting that both stimuli can be used for neurological diagnoses with the same reliability.

• Korean Journal of Audiology
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• v.25 no.1
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• pp.14-21
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• 2021

Background and Objectives: There is growing interest in the use of the Level-specific (LS) CE-Chirp^® stimulus in auditory brainstem response (ABR) due to its ability to produce prominent ABR waves with robust amplitudes. There are no known studies that investigate the test-retest reliability of the ABR to the LS CE-Chirp^® stimulus. The present study aims to investigate the test-retest reliability of the ABR to the LS CE-Chirp^® stimulus and compare its reliability with the ABR to standard click stimulus at multiple intensity levels in normal-hearing adults. Subjects and Methods: Eleven normal-hearing adults participated. The ABR test was repeated twice in the same clinical session and conducted again in another session. The ABR was acquired using both the click and LS CE-Chirp^® stimuli at 4 presentation levels (80, 60, 40, and 20 dBnHL). Only the right ear was tested using the ipsilateral electrode montage. The reliability of the ABR findings (amplitudes and latencies) to the click and LS CE-Chirp^® stimuli within the same clinical session and between the two clinical sessions was calculated using an intra-class correlation coefficient analysis (ICC). Results: The results showed a significant correlation of the ABR findings (amplitude and latencies) to both stimuli within the same session and between the clinical sessions. The ICC values ranged from moderate to excellent. Conclusions: The ABR results from both the LS CE-Chirp^® and click stimuli were consistent and reliable over the two clinical sessions suggesting that both stimuli can be used for neurological diagnoses with the same reliability.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.808-813
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• 2011

There are hundreds of thousands call center workers wearing acoustic device. However, researches and noise exposure measurements on the noise transmitted from acoustic devices have seldom been performed due to the difficulty of measurement and to the absence of the measuring method in Korea. The aim of this study is to set up management measures to protect hearing loss on the call operator by acquiring measurement data of noise transmitted from the headset Noise exposure measurements of 17 operators were performed in 7 call centers and Head and Torso Simulator method in compliance with the ISO Standard 11904-2 was used for the measurement of noise transmitted from the headset Sound pressure levels(SPL) transmitted from the headset were 73.2~86 dB(A). The operator exposed to the highest SPL set up his volume control at 9 which was the highest volume level. The volume control level, adjustable from 1 to 9, could be identified 12 out of 17 operators and the range of volume levels was 4.5~9. As a result of Pearson Correlation Analysis, the correlation between volume level and SPL transmitted from the headset showed high relation as significance at the 0.672 level(p<0.05). To protect hearing loss of call center operators, it is more practical and effective measure to limit the volume level below the noise exposure level, i.e. 85 dB(A), rather than to carry out noise monitoring considering cost-effective aspect.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.7
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• pp.615-621
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• 2011

There are hundreds of thousands call center workers wearing acoustic device. However, researches and noise exposure measurements on the noise transmitted from acoustic devices have seldom been performed due to the difficulty of measurement and to the absence of the measuring method in Korea. The aim of this study is to set up management measures to protect hearing loss on the call operator by acquiring measurement data of noise transmitted from the headset. Noise exposure measurements of 17 operators were performed in 7 call centers and head and Torso simulator method in compliance with the ISO standard 11904-2 was used for the measurement of noise transmitted from the headset. Sound pressure levels(SPL) transmitted from the headset were 73.2~86 dB(A). The operator exposed to the highest SPL set up his volume control at 9 which was the highest volume level. The volume control level, adjustable from 1 to 9, could be identified 12 out of 17 operators and the range of volume levels was 4.5~9. As a result of pearson correlation analysis, the correlation between volume level and SPL transmitted from the headset showed high relation as significance at the 0.672 level(p<0.05). To protect hearing loss of call center operators, it is more practical and effective measure to limit the volume level below the noise exposure level, i.e. 85 dB(A), rather than to carry out noise monitoring considering cost-effective aspect.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1979.05a
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• pp.4.4-5
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• 1979

The degree of hearing impairment of chronic otitis media will indicate the nature and severity of middle ear pathology especially condition of ossicular chain, size of ear drum perforation and location of granulation tissue in the middle ear cavity. The subjects were 189 ears of tympanoplasty for chronic otitis media and divided into four groups as follows: Normal ossicular chain with only ear drum perforation (group I), normal ossicular chain with granulation tissue only around the ossicles regardless of any other region (group II), ossicular ankylosis or fixation of handle of malleus to promontory with or without granulation tissue around the ossicle (group III) and ossicular interruption by partial or complete destruction(groupf IV). The results were concluded as follows: 1) The average hearing threshold of chronic otitis media was 44.6 dB and hearing threshold was closely related to the condition of ossicular chain. Hearing threshold became greater in order of normal ossicular chain, ankylosis and interruption. 2) The average hearing threshold of ossicular interrupted group was 49.1 dB and it was greater in the cases of total destruction than that of partial destruction. 3) The hearing loss in the cases of normal ossicular chain with only tympanic membrane perforation was within 45 dB and this level was presumed to represent normal ossicular function. The degree of hearing loss was in proportion to the size of ear drum perforation and when over 45 dB, other middle ear pathology was suggested. 4) In the cases of small ear drum perforation with normal ossicular function, the hearing threshold was within 30 dB. 5) In the type of audiogram, flat type was 30.2% and ascending type 35.4%. Descending type was more frequent in the cases of normal ossicular mobility with granulation tissue around the ossicle and flat type was observed frequently in the cases of ossicular ankylosis. 6) Carhart's notch was seen in 14 cases (7.4%) and observed mainly in ossicular ankylosis. 7) There was no relation between hearing threshold and histopathological type of granulation tissue in chronic otitis media. However the degree of hearing impairment was related to the location of granulation tissue in the middle ear cavity. 8) Authors recognized the granulation tissue compensated the function of interrupted ossicular chain.

• Safety and Health at Work
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• v.2 no.4
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• pp.336-347
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• 2011

Objectives: In Korea, an average of 258 workers claim compensation for their noise-induced hearing loss (NIHL) on an annual basis. Indeed, hearing disorder ranks first in the number of diagnoses made by occupational medical check-ups. Against this backdrop, this study analyzed the impact of 19 types of noise-generating machines and equipment on the sound pressure levels in workplaces and NIHL occurrence based on a 2009 national survey on work environments. Methods: Through this analysis, a series of statistical models were built to determine posterior probabilities for each worksite with an aim to present risk ratings for noise levels at work. Results: It was found that air compressors and grinding machines came in first and second, respectively in the number of installed noise-generating machines and equipment. However, there was no direct relationship between workplace noise and NIHL among workers since noise-control equipment and protective gear had been in place. By building a logistic regression model and neural network, statistical models were set to identify the influence of the noise-generating machines and equipment on workplace noise levels and NIHL occurrence. Conclusion: This study offered NIHL prevention measures which are fit for the worksites in each risk grade.