Audiometric notch as a sign of noise induced hearing loss.
OBJECTIVES To investigate the relation between different types of exposure to noise and a classic sign of noise induced hearing loss (NIHL), the audiometric notch. METHODS The study sample had exposure to both continuous and impulse noise and was drawn from a population of electrical transmission workers. Audiograms, taken as part of a hearing conservation programme, were read by three clinicians experienced in the assessment of NIHL. Working independently and using their clinical judgment, they were asked to identify localised increases in the threshold of hearing (audiometric notches) which they would attribute to noise, had a suitable history of exposure been elicited. Prevalent cases of NIHL were identified by the presence of a notch in either ear. Risk factors for NIHL were assessed by a questionnaire which sought information about exposure to air blast circuit breaker noise; firearms; explosions, and continuous noise. The odds of exposure to these factors in those with and without hearing loss were calculated, and odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated by logistic regression. RESULTS Of the 648 questionnaires sent out 357 were returned, a response rate of 55%. Of these, at least two out of the three assessors identified 175 (49%) people with a notch at any audiometric frequency. There was no association between these cases and the NIHL risk factors identified by the questionnaire, but a further frequency specific analysis showed a small proportion of people (15 (4%)) with notches at 4 kHz who had the expected associations with exposure to noise and a significant OR for firearms of 4.25 (95% CI 1.28 to 14.1). The much larger proportion of people with 6 kHz notches (110 (31%)) did not show these associations. CONCLUSIONS To diagnose NIHL it is important to elicit a detailed and accurate history of exposure to noise: although the notch at 4 kHz is a well established clinical sign and may be valuable in confirming the diagnosis, the 6 kHz notch is variable and of limited importance.
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Introduction: Nowadays, noise exposure is one of the most important industrial health problems. Noise exposure can cause hearing loss and many other health problems. So, paying attention to the noise exposure problem should be of main priority in industrial health programs. This study was conducted in an oil producing region, aimed to assess noise pollution and noise induced hearing loss. Met...متن کامل
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An assessment of hearing thresholds among student orchestral musicians was carried out at the UCL Ear Institute in conjunction with the Royal College of Music (RCM). Audiogram data taken from 162 students (86 F, 76 M; mean age=23.7 years, SD=4.8) showed a statistically significant notch at 6 kHz in the left ear, indicative of noise-induced hearing loss (NIHL), but no significant notch was found...متن کامل
Analysis of audiometric notch as a noise-induced hearing loss phenotype in US youth: data from the National Health And Nutrition Examination Survey, 2005-2010.
OBJECTIVE Bilateral audiometric notch (BN) at 4000-6000 Hz was identified as a noise-induced hearing loss (NIHL) phenotype for genetic association analysis in college-aged musicians. This study analysed BN in a sample of US youth. DESIGN Prevalence of the BN within the study sample was determined and logistic-regression analyses were performed to identify audiologic and other demographic fact...متن کامل