[Extended high frequency audiometry in the prevention of noise-induced hearing loss]

An early detection of noise induced hearing loss (NIHL) may allow more effective protection measures. Our aim was to investigate the usefulness of high-frequency audiometry to evaluate the possibility of a future use of the high frequencies audiometry as an early indicator for noise induced hearing loss. A cross-sectional study was performed involving 204 industrial noise exposed and 100 non-industrial noise-exposed workers. Each subject was tested with both conventional-frequency (0.25-8 kHz) and high-frequency (9-18 kHz) audiometry during the annually health surveillance campaign conducted in two Italian cement factories. As expected, noise exposed workers were found to have significantly higher hearing thresholds (P < 0.05) at both conventional and extended high frequencies. Marked differences were found for EHFA. Moreover, significant differences at EHFA were detected also in the subgroup of noise-exposed workers with normal findings at conventional audiometry. Our finding indicate that the use of the extended high frequency test may represent a useful tool for detecting early changes of hearing impairment and that it could be used in addition to the conventional test to better prevent the progression of noise hearing loss.