[Auditory brainstem responses evaluation of retrocochlear disease in workers from a general hospital exposed to noise]

Abstract

The main purpose of this cross-sectional study was to investigate the presence of retrocochlear disease in a group of maintenance workers from a general hospital, who presents a history of noise exposure. Thirty one workers of three engineering sections with age range from 25 to 60 years and continuous noise exposure from 2 and 45 years, were examined. The evaluation included an audiometric occupational selection and auditory brainstem responses (ABR). ABR abnormalities were detected in seven patients (22.6%) and it was found latency increase of waves III (14.3%) and V (28.6%), and interpeak prolongation I-III (71.4%), III-V (28.6%) and I-V (85.7%). Among 35 ears with normal audition - right, left or both -, four (11,4%) ears presented retrocochlear disease. The high retrocochlear disease prevalence in workers exposed to noise lead us to suppose that this disturbance is more frequent than usually found; therefore it is underestimated in workers diagnostic evaluation. The presence of this kind of disturbance, even with the absence of audiometric alterations, suggests that ABR is more sensitive than the tonal audiometry for noise induced hearing loss investigation.