Processamento auditivo de militares expostos a ruído ocupacional: um estudo longitudinal

Abstract

The hearing evaluation that has been doing on occupational environment easily detects the noise induced hearing loss (NIHL), however, alterations on the central auditory pathway can not be observed. Studies have showed a relation between the noise exposure time and the increase of the incidence of hearing loss, but do not demonstrate how the auditory processing can be affected by the exposure time of that risk. Therefore, this study had as objective to evaluate the influence of working time on the central auditory function of military personnel exposed to occupational noise. It were evaluated 41 militaries, with at least 10 years of noise exposure, divided into group A (n = 16), without hearing loss and group B (n = 25), with hearing loss. To configure a longitudinal study, were invited the same individuals studied by Marins (2004) and were submitted to the same evaluations three years after the referred study: basic hearing evaluation and auditory processing tests (Low- Pass Filtered Speech, SSW and Pitch Pattern Sequence - PPS tests). A higher occurrence of auditory processing alterations were observed, specially on Low-Pass Filtered Speech test (43,75% and 68% on groups A and B, respectively) and PPS (68,75% and 48% on groups A and B, respectively). Longitudinally, statistical analysis revealed a significant decrease of Speech ecognition Index, just in the group B, in both ears; on the Low-Pass Filtered Speech test of group B (right and left ears) and just in the left ear of group A. Then, it was concluded that the occupational noise exposure interferes on the auditory processing of military personnel, and that increase with the working time