[Recording otoacoustic emissions in expert evaluation of chronic noise-induced hearing loss].

In order to assess occupational hearing loss, damage to outer hair cell function must be demonstrated. Measurements of transiently evoked otoacoustic emissions (TEOAE) and distortion products (DPOAE) allow clinicians to investigate objectively the cochlear amplification process. In this prospective study, 50 persons with suspected occupational hearing losses were tested with pure-tone and speech audiometry. Additionally, TEOAE and DPAOE were determined. Significant linear correlations were observed when comparing hearing thresholds and speech discriminations with evoked emissions. Three groups were formed based on the OAE results: group A, TEOAE- and DPOAE-positive; group B, TEOAE-negative, DPOAE positive; group C, TEOAE- and DPOAE-negative. The groups were compared with regard to the weighted and simple discrimination scores and percentage of hearing loss computed according to the Boenninghaus-Röser tables. Analysis of variance showed significant differences in hearing losses among the three groups, allowing an objective statement to be made about the degree of work compromise: group A, < 10%; group B, 10-15% group C, > or = 20%.