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Biomedical subjects

D Y Chung

Publications and source records attributed to D Y Chung.

31 records · Page 2Linked to original sources
PubMed1981

Masking, temporal integration, and sensorineural hearing loss.

This study was undertaken basically to examine the effect of white noise masking on temporal integration and how the frequency dependence of temporal integration is related to hearing loss. The threshold differences between 500-msec and 20-msec tones at .5, 1, 2, and 4 kHz were found for 147 ears of 86 subjects with normal hearing and with various amounts of cochlear hearing loss. Thresholds were measured in three levels of background white noise--30, 60, and 90 dB SPL. The principal finding was that temporal integration is frequency dependent and this dependence is not an epiphenomenon of the decrease in temporal integration due to cochlear hearing loss.

Aged↗
PubMed1981

Shooting, sensorineural hearing loss, and workers' compensation.

Pure-tone audiograms of 29,953 workers with histories of shooting and occupational noise exposure were analyzed. The analysis was based on the asymmetry of hearing loss. Results of this study show that shooting is related to asymmetrical hearing loss, suggesting that shooting may cause an additional amount of hearing loss other than that due to occupational noise exposure. Asymmetry was found to increase as the length of shooting history increased and was significant only at 2 kHz and above and most prominent at 4 kHz. Results also indicated that as long as compensable frequencies remain below 3 kHz the shooting effect is not likely to influence compensation for workers with histories of less than ten years of shooting.

Hearing Loss, Noise-Induced↗
PubMed1981

Speech discrimination and effectiveness of hearing aids under listening conditions similar to those of a transit operator.

Some controversy exists regarding regulations that permit hearing impaired drivers to operate passenger carrying vehicles. In other situations it has been shown that the hearing impaired generally have more difficulty than normals discriminating speech in noise. The present study investigates this under listening conditions simulating those of a transit operator, and also looks at the effects of a hearing aid on speech discrimination in the same situation. One normal hearing group and three groups representing varying degrees of symmetrical sensorineural hearing loss were given a sentence type discrimination test in a background of recorded diesel bus noise at different speech-to-noise ratios. The hearing impaired groups performed more poorly than normals and the use of hearing aids did not affect the performance of the hearing impaired groups. Regulations pertaining to licensing of transit operators should take into account hearing above 2,000 Hz. The results of this study, combined with the possibility of noise damage from amplified noise levels, lead us to conclude that hearing aids should not be worn by transit operators on the job.

Analysis of Variance↗
PubMed1980

Hearing loss due to noise trauma.

Three different types of noise-induced hearing loss have been reported in the literature. The two less common types are described here. Three cases of these two types from our clinic are reported. Since these 2 types of noise-induced hearing loss often involve low frequencies it is important to recognize them in compensation cases.

Adult↗
PubMed1980

Meanings of a double-notch audiogram.

Audiological findings in patients with histories of noise exposure were examined. 27 patients (1.5%) were found to have audiograms with a double-notch configuration. Information from their occupational history, medical history, and audiological findings was gathered and analysed. Their results were compared with those of 50 random samples of patients without the double-notch audiogram. Analyses suggest that the low frequency notch is probably also caused by noise damage. The low incidence of double-notch audiogram reflects the small proportion of people with susceptibility to noise damage at the 500 Hz to 1 kHz region in addition to the 3 to 6 kHz region. This double-notch configuration could be exaggerated possibly by the release from inhibition by damaged hair cells.

Adult↗
PubMed1980

Quiet and masked brief-tone audiometry in subjects with normal hearing and with noise-induced hearing loss.

Twenty subjects with normal hearing and 20 with noise-induced hearing loss (NIHL) were tested with brief-tone audiometry at 500 and 4000 Hz in both quiet and masked conditions. The two tone durations used were 20 and 500 msec. The masker was a continuous white noise at 90 dB SPL. Results are consistent with other studies in that subjects with NIHL showed less temporal integration than normals. The frequency effect was found both in normals and in the hearing-impaired. The discrepancy of results on frequency effect found in the literature was discussed. Also, results suggest that suprathreshold measurement of temporal integration with the masking technique deserves further study.

Adult↗
PubMed1979

Interaction of kanamycin and noise exposure.

The amount of hair cell damage in the cochleas of guinea pigs after exposure to different experimental conditions suggests that a 'safe' level of kanamycin has a potentiating effect on damage due to noise. Such an effect lasts more than 20 days after the cessation of the drug administration.

Animals↗
PubMed1979

The effect of masking by noise on word discrimination scores in listeners with normal hearing and with noise-induced hearing loss.

Patients with high-frequency hearing loss often complain at the Workers' Compensation Board that they find it difficult to hear speech in a noisy environment. This study was undertaken to test the validity of their complaints. The experiment had a 2x3x3 factorial design. The factors were subject group (normal hearing versus sensorineural hearing loss), stimulus level (65, 75, and 85 dB SPL), and speech-to-noise ratio (5, 12, and 19 dB). There were 6 subjects in each condition. Each subject was tested for his speech discrimination with three CID W-22 50-word lists, one in each of the three different speech-to-noise ratios. Both speech and pink noise were presented through loudspeakers in a sound field. The results support the patients' complaints. Possible explanations for the results are discussed.

Adult↗
PubMed1979

Is a healthier person less susceptible to noise-induced hearing loss?

Several studies in the literature suggest that poor health is related to hearing loss. One hundred subjects claiming occupational hearing loss were chosen randomly for this study. Information was obtained on employment, noise exposure, medical history, family history, and use of cigarettes, alcohol, and medication. Physical examination audiometric tests, and biological tests were carried out. Computer analysis of the data with chi-square test did not show conclusively that noise-induced hearing loss is related to poor health, indicated by abnormal biological or physical findings, or both. There were, however, some indications that the presence of cardiovascular risk factors may influence hearing loss.

Analysis of Variance↗
PubMed1978

Relationship between uncomfortable loudness level and acoustic reflex threshold as a function of hearing loss.

While many studies examined the relationship between Acoustic Reflex Threshold (ART) and Uncomfortable Loudness Level (UCL) and the possibility of predicting one from the other, no study to the authors' knowledge has shown the relationship between these two measures with respect to hearing loss, and uses such a relationship to predict either measure from the other plus the hearing loss. To achieve these relationships and uses, 80 Ss were studied, 20 in each of 4 groups, with normal hearing and with mild, moderate, and severe noise-induced hearing loss. ARTs and UCLs were obtained at 0.5, 1, 2, and 4 kc/s. The results demonstrated that db sensation level (SL) of ART and UCL were highly correlated with pure-tone hearing threshold level (HTL). An equation was derived: UCL (in db SL) - ART (in db SL) = 6 - .05 HTL, which shows that the relationship between ART and UCL varies as a function of hearing loss. Data from other studies were compared and discussed.

Adult↗
PubMedDate not supplied

The effect of ear protectors on word discrimination in subject with normal hearing and subjects with noise-induced hearing loss.

Two groups of subjects with normal hearing and three groups of subjects with noise-induced hearing loss were studied for the effect of ear protectors on word discrimination in two different speech-to-noise ratios. Various interactions in the analyses of variance were shown to be significant. The important demonstration in this study is that at high speech intensity, subjects with normal hearing should obtain higher word discrimination score with ear protectors than without if the signal-to-noise ratio is high. Albeit, the same is not true for a low signal-to-noise ratio, for a low speech intensity, or when subjects have hearing losses; the improvements in these conditions are not high enough to warrant the disuse of ear protectors. Results are discussed and compared with other studies.

Ear Protective Devices↗
PubMedDate not supplied

The effect of middle ear disorders on noise-induced hearing loss.

Two groups of subjects, 50 noise-exposed and 50 non-noise-exposed, both with unilateral conductive hearing loss, were studied in terms of the amount of conductive hearing loss and difference in the bone conduction thresholds at 4 kHz between the two ears. The results support the hypothesis that middle ear disorders provide the ear some protection from noise-induced hearing loss.

Adult↗