• The Journal of the Acoustical Society of Korea
• /
• v.40 no.6
• /
• pp.678-682
• /
• 2021

Reverberation Time (RT) with noise levels can affect speech recognition ability in a listening environment. The degree of influence may depend on reverberation times and modes of binaural hearing. In this study, Korean monosyllabic Word Recognition Scores (WRS) were investigated in 10 young normal hearing subjects under binaural conditions. The RT of 3.4 s and signal to noise ratio of 0 dB were used at 55 dB HL for diotic (noise with the same phase) and dichotic (noise with the fixed phase difference, π) conditions. The improvement in WRS was noted in dichotic hearing (p < 0.05) while the similar trend was not observed in diotic hearing. This data may be useful in analyzing psychoacoustic effects of RTs under noisy conditions.

• Korean Journal of Social Welfare
• /
• v.66 no.3
• /
• pp.55-73
• /
• 2014

The purpose of this study was to develop and validate Korean version of Deaf Acculturation Scales(DAS). Pilot items were made a faithful translation of the Acculturation Scales of Maxwell-McCaw and Zea (2011) and were modified for Korean Deaf people. The Scale involves two dimensions, in order to measure the acculturation of Deaf people; Deaf acculturation and hearing acculturation. Using factor analysis, we developed a Korean version of DAS consisted of twenty-five items for Deaf acculturation dimension and twenty-five items for hearing acculturation dimension. These analysis supported the four factors of Deaf acculturation dimension and the five factors of hearing acculturation dimension. Reliability, assessed by Cronbach's ${\alpha}$, was .93 for Deaf acculturation and .93 for hearing acculturation, respectively, which confirm the Koran version of DAS. Construct validity was demonstrated through correlation with Deaf acculturation-related variables: age, age of Deafness, Degree of hearing loss, American Sign Language ability, and lip-reading ability. Criterion validity was supported by correlation with Collective Self-Esteem Scale. Limitation and implication of this study and direction for future research were discussed.

• Clinical and Experimental Pediatrics
• /
• v.49 no.10
• /
• pp.1056-1060
• /
• 2006

Purpose : As hearing ability affects language and cognitive development, early detection and intervention of congenital hearing defects is very important. We analyzed the result of newborn hearing screening using automated auditory brainstem response and estimated the incidence of congenital hearing defects in newborn infants in Korea. Methods : Hearing screening tests were done on 7,218 newborn infants who were delivered at Cheil General Hospital from July 1, 2004 to June 30, 2005. The first screening test was done on the second day of life with automated auditory brainstem response(AABR) using $ALGO{\bigcirc}^{(3)}$ Newborn hearing screener($Natus^{(R)}$ Medical Incorporated, San Carlos, USA) with 35 dB sound level. The newborn infants who did not pass the initial screening test took the second screening AABR test before discharge from the nursery. Infants who did not pass these screenings at the nursery were followed up at the Department of Otorhinolaryngology, Samsung Seoul Hospital. Results : Total 7,218 infants(83.3 percent of total 8,664 live births of the Cheil General Hospital) were screened in the nursery, and 55 of them failed to pass the newborn screening. Among 55 infants who were referred, six were lost during follow-up, and 14 were confirmed as hearing impaired. Six of them(42.8 percent) do not have any risk factors for hearing impairment. We can estimate that the incidence of hearing defects is about 1.9-2.8 per 1,000 live births. Conclusion : Automated auditory brainstem response is an effective tool to screen the hearing of newborn infants. Congenital hearing loss is more frequent than metabolic diseases on which screening tests are available in the newborn period. About 40 percent of infants who have hearing defects do not have any risk factors for hearing impairment. Therefore, universal newborn hearing screening must be recommended to all neonates.

• Journal of Biomedical Engineering Research
• /
• v.34 no.1
• /
• pp.24-33
• /
• 2013

To enhance the speech perception of hearing aid users in noisy environment, most hearing aid devices adopt various beamforming algorithms such as the first-order differential microphone (DM1) and the two-stage directional microphone (DM2) algorithms that maintain sounds from the direction of the interlocutor and reduce the ambient sounds from the other directions. However, these conventional algorithms represent poor directionality ability in low frequency area. Therefore, to enhance the speech perception of hearing aid uses in low frequency range, our group had suggested a fractional delay subtraction and integration (FDSI) algorithm and estimated its theoretical performance using computer simulation in previous article. In this study, we performed a KEMAR test in non-reverberant room that compares the performance of DM1, DM2, broadband beamforming (BBF), and proposed FDSI algorithms using several objective indices such as a signal-to-noise ratio (SNR) improvement, a segmental SNR (seg-SNR) improvement, a perceptual evaluation of speech quality (PESQ), and an Itakura-Saito measure (IS). Experimental results showed that the performance of the FDSI algorithm was -3.26-7.16 dB in SNR improvement, -1.94-5.41 dB in segSNR improvement, 1.49-2.79 in PESQ, and 0.79-3.59 in IS, which demonstrated that the FDSI algorithm showed the highest improvement of SNR and segSNR, and the lowest IS. We believe that the proposed FDSI algorithm has a potential as a beamformer for digital hearing aid devices.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.2
• /
• pp.151-155
• /
• 2001

In order to obtain the fundamental data on the auditory thresholds of fishes for marine ranching, the auditory thresholds of black rockfish Sebastes inermis were measured in the presence of masking noise in the spectrum level range of $73\~83$ dB (0 dB re $1{\mu}Pa/\sqrt{Hz}$) with a classical cardiac conditioning technique. Critical ratios were about $28\~34$ dB at $80\~300$ Hz and $47\~52$ dB at $500\~800$ Hz. The ratio increased almost linearly with increasing frequency to 500 Hz. The noise spectrum level at the start of masking was about 70 dB within the frequency range of $80\~800$ Hz excepting 65 dB at 300 Hz. It means that hearing of the black rockfish is masked in the natural environment with the noise spectrum level above 65 dB. The sound pressure level of $200\~300$ Hz recognized by black rockfish was above 96 dB under the ambient noise and the critical ratio of them was above 26 dB.

• Phonetics and Speech Sciences
• /
• v.2 no.3
• /
• pp.171-178
• /
• 2010

This study examined the relationship between speech intelligibility and comprehensibility for hearing impaired children with cochlear implants. Speech intelligibility was measured by orthographic transcription method for acoustic signal at the level of words and sentences. Comprehensibility was evaluated by examining listener's ability to answer questions about the contents of a narrative. Speech samples were collected from 12 speakers(age of 6~15 years) with cochlear implants. For each speaker, 4 different listeners(total of 48 listeners) completed 2 tasks: One task involved making orthographic transcriptions and the other task involved answering comprehension questions. The results of the study were as follows: (1) Speech intelligibility and comprehensibility scores tended to be increased by decreasing of severity. (2) Across all speakers, the relationship was significant between speech intelligibility and comprehensibility scores without considering severity. However, within severity groups, there was the significant relationship between comprehensibility and speech intelligibility only for moderate-severe group. These results suggest that speech intelligibility scores measured by orthographic transcription may not accurately reflect how well listener comprehend speech of children with cochlear implants and therefore, measures of both speech intelligibility and listener comprehension should be considered in evaluating speech ability and information-bearing capability in speakers with cochlear implants.

• Journal of Fisheries and Marine Sciences Education
• /
• v.25 no.2
• /
• pp.341-348
• /
• 2013

The auditory thresholds for 7 specimens of the sharp toothed eel Muraensox cinerus were measured at 5 frequencies by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of the sharp toothed eel extended from 80Hz to 300Hz with the best sensitivity around 80Hz and 100Hz. In addition, the auditory thresholds over 200Hz increased rapidly. The mean auditory thresholds of the sharp toothed eel at the test frequencies of 80Hz, 100Hz, 200Hz and 300Hz were 87dB, 86dB, 105dB and 126dB, respectively. Auditory masking was determined for the sharp toothed eel by using masking stimuli with the spectrum level range of about 70~80dB (0dB re $1{\mu}Pa/\sqrt{Hz}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise. The noise spectrum level at the start of masking was distributed at the range of about 64dB within 80~100Hz. Critical ratio ranged from minimum 24dB to maximum 40dB at test frequencies of 80Hz~200Hz.

• Speech Sciences
• /
• v.7 no.2
• /
• pp.37-50
• /
• 2000

This paper describes a test of everyday speech understanding ability, in which a listener's utilization of the context-situational information of speech is assessed, and is compared with the utilization of acoustic-phonetic information. The test items are sentences which are presented in a babble type of noise, and the listener response is the key word in the sentence. The key words are always two-syllabic nouns and the questioning sentences are added to obtain the responding key words. Two types of sentences are used. One is the high-predictable sentences for which the key word is somewhat predictable from the context. The other is the low-predictable sentences for which the key-word cannot be predicted from the context. Both types are included in six 40-item forms of the test, which are balanced for intelligibility, key-word familiarity and predictability, phonetic content, and length. Performance of normally hearing listeners shows significantly different functions for various signal-to-noise ratios. The potential applications of this test, particularly in the assessment of speech understanding ability in the hearing impaired, are discussed.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.36 no.4
• /
• pp.309-313
• /
• 2000

A experiment was carried out to measure the auditory threshold of dusky spinefoot Siganus fuscescens(Houttuyn) in the coast of Cheju Island by heartbeat conditioning technique using pure tones coupled with a delayed electric shock in order to investigate the hearing ability to audible sound. The audible range of dusky spinefoot extended from 80Hz to 800Mhz with a peak sensitivity at 200Hz. The mean auditory threshold levels of dusky spinefuot were 102dB, 96dB, 92dB, 95dB, 105dB and 121dB respectively in the range of measurement frequencies, As the frequency became higher than 300Hz, the auditory threshold increased rapidly.

• Korean Journal of Audiology
• /
• v.24 no.1
• /
• pp.1-9
• /
• 2020

Auditory scene analysis is defined as a listener's ability to segregate a meaningful message from meaningless background noise in a listening environment. To gain better understanding of auditory perception in terms of message integration and segregation ability among concurrent signals, we aimed to systematically review the size of auditory scenes among individuals. A total of seven electronic databases were searched from 2000 to the present with related key terms. Using our inclusion criteria, 4,507 articles were classified according to four sequential steps-identification, screening, eligibility, included. Following study selection, the quality of four included articles was evaluated using the CAMARADES checklist. In general, studies concluded that the size of auditory scene increased as the number of sound sources increased; however, when the number of sources was five or higher, the listener's auditory scene analysis reached its maximum capability. Unfortunately, the score of study quality was not determined to be very high, and the number of articles used to calculate mean effect size and statistical significance was insufficient to draw significant conclusions. We suggest that study design and materials that consider realistic listening environments should be used in further studies to deep understand the nature of auditory scene analysis within various groups.