Noise exposure and hearing loss among student employees working in university entertainment venues.
(1/12)
OBJECTIVES: Most studies to date on sound levels in entertainment establishments have concentrated on exposure levels for the attending public, rather than employees who may be at greater risk of hearing loss. Of particular concern are young employees. The aim of this pilot study was to (i) estimate typical sound levels in different areas where amplified music was played, (ii) measure temporary threshold shift (TTS) and (iii) estimate the dependence of hearing threshold shifts on measured noise levels. METHODS: This study focused on students working part-time (up to 16 h/week) in music bars and discotheques in a university entertainment venue. All 28 staff were invited to participate in the study. Pre- and post-exposure audiometry was used to determine hearing threshold at both high and low frequencies. Personal dosemeters and static measurements were made to assess noise levels and frequency characteristics. A questionnaire was used to determine patterns of noise exposure and attitudes to noise levels and hearing loss. RESULTS: Of the 28 student employees working in the three areas, 14 (50%) agreed to take part in the study, giving 21 pre- and post-shift audiograms. The mean personal exposure levels for security staff were higher than those of bar staff, with both groups exceeding 90 dB(A). The maximum peak pressure reading for security staff was 124 dB. Although TTS values were moderate, they were found to be highly significant at both low and high frequencies and for both ears. Twenty-nine per cent of subjects showed permanent hearing loss of more than 30 dB at either low or high frequencies. The correlation between TTS and personal exposure was higher at 4 kHz than the low and high frequencies. CONCLUSIONS: Contemporary music may be an important yet little considered contributor to total personal noise exposure, especially amongst young employees. Employees need to be better informed of risks of hearing loss and the need to report changes in hearing acuity. Suggestions are made on strategies for improving the assessment of noise exposure in entertainment venues. (+info)
Evaluation of auditory fatigue in combined noise, heat and workload exposure.
(2/12)
This study was performed in a climatic chamber to evaluate the combined effects of noise intensity, heat stress, workload, and exposure duration on both noise-induced temporary threshold shift (TTS) and the recovery time by adopting Taguch's method. Fourteen subjects without previous significant noise exposure and smoking history were recruited to participate in this study. All hearing threshold levels at eight different frequencies (250 to 8,000 Hz) of better ear were measured in an audiometric booth by using the ascending method in 2 dB steps before each exposure condition. The test was also carried out after exposure to evaluate TTS at various times. The TTS recovery time was assessed using an audiometric test on all subjects at post-exposure times of 2, 20, 40, 60, 80 and 120 min, respectively. It was found that TTS depended mainly on the exposed noise dose and was enhanced by workload and heat stress. The TTS recovery time is dependent upon the magnitude of the initial hearing loss. In conclusion, TTS driven by noise exposure is enhanced by heat and workload. Further studies are required to evaluate the effects of workload with extreme temperature in a workplace environment. (+info)
The efficiency of otoacoustic emissions and pure-tone audiometry in the detection of temporary auditory changes after exposure to high sound pressure levels.
(3/12)
Exposure to noise has a harmful effect on the auditory health of workers. AIM: The main goal of this paper was to establish the role of pure-tone audiometry and evoked transient otoacoustic emissions in the detection of small temporary auditory changes after exposure to high sound pressure levels. STUDY DESIGN: A cross-sectional cohort study. MATERIAL AND METHODS: 30 otologically normal subjects aged between 20 and 35 years were submitted to pure-tone audiometry and evoked transiente otoacoustic emissions before and after 5 hours of exposure to high sound pressure levels (between 80 and 90 dB). RESULTS: For pure-tone audiometry the largest changes occurred at high frequencies--from 3 KHz to 8 KHz after exposure. The evoked transient otoacoustic emissions showed reduced reproductibility from 1 KHz to 4 KHz after exposure to noise. CONCLUSION: We noted that both pure-tone audiometry and evoked transient otoacoustic emissions had a role in detecting statistically significant changes in the auditory threshold and in reproductibility, after exposure to high sound pressure levels. (+info)
Temporary threshold shifts at 1500 and 2000 Hz induced by loud voice signals communicated through earphones in the pinball industry.
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