ORIGINAL ARTICLES   

Minerva Medicolegale 2000 December;120(4): 193-8

Copyright © 2000 EDIZIONI MINERVA MEDICA

language: Italian

Assessment of etiology in noise induced hearing loss. Possibility and limits

Testa B., Morelli G., Testa D., Motta G. Jr.

Background. To research the causes responsible for the high rate of professional illness due to noise induced hearing loss and the relevant damage compensation in Italy.
Methods. 2167 workers who had professional illness claims for noise induced hearing loss were enrolled for our research, 2005 men and 162 women, patients' history, ear, nose and throat examinations, pure tone audiometry, tympanometry and middle ear muscle reflex were investigated for labyrinthine damage assessment.
Results. Audiometric tests showed: sensorineural hearing loss (HTL > 25 dB) in 702 workers (32.3%); deep on 4000 Hz 254 workers (11.7%); mixed hearing loss in 344 cases (15.8%); conductive hearing loss in 354 workers (16.3%); hearing threshold level ¾ to 25 dB in 420 workers (19.4%); 93 uncollaborative workers (4.2%). Real labyrinthine damage was found only in 60% of the enrolled cases.
Conclusions. Our research showed labyrinthine damage from chronic acoustic trauma in only 60% of the cases, for this reason the remaining 40% of claims were unfounded. However, since noise induced hearing loss does not have specifically recognizable characteristics, the 60% of ascertained labyrinthine damage may also be due to other etiologies. If the labyrinthine damage noise induced does not have a certain character of specificity, the times and modalities of its realization are, however, different. This can be assessed on the basis of periodic audiometric and phonometric findings. These data have been available in Italy only since 1991. However, as such damage is established after more than a decade of exposition to noise, they are not particularly significant for valid etiology assessment today.