The purpose of this study was to investigate hearing threshold changes of workers with unilateral conductive hearing loss who were exposed to workplace noise for 8-years.
Among 1819 workers at a shipyard in Ulsan, 78 subjects with an air-bone gap ≥10 dBHL in unilateral ears were selected. Factors that could affect hearing were acquired from questionnaires, physical examinations, and biochemistry examinations. Paired
The study included male subjects aged 48.7 ± 2.9, having worked for 29.8 ± 2.7 years. Hearing thresholds increased significantly in CHL ears and SNHL ears at all frequencies (0.5–6 kHz) during follow-up period (
At high-frequencies, particularly at 4 kHz, the range of hearing threshold changes was lower in ears with conductive hearing loss than in contralateral ears. This is suggested as a protective effect against noise exposure.
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