Brainstem evoked response in bus drivers with noise-induced hearing loss.
Studies carried out by Brainstem Evoked Auditory Potentials (BEAP) in Noise-Induced Hearing Loss (NIHL) workers show different results in relation to neuronal involvement, not involving bus drivers as study object.


OBJECTIVE
to use BEAP in a prospective case/control clinical study to check whether or not there is neural auditory pathway involvement in bus drivers with NIHL.


METHODS
we selected 50 bus drivers between 27 and 40 years with mild to moderate NIHL, and 20 individuals between 29 and 40 years with normal hearing and without prior history of noise exposure. BEAP tests were carried out and the traces were analyzed.


RESULTS
in the NIHL group, the auditory thresholds in 3, 4 and 6 kHz were significantly higher in the left ear. In the NIHL group, potentials PI, PIII and/or PV were not present in a small number of the individuals; we observed a statistically significant increase in PI, PIII and PV absolute latencies, (LIP) LIP I-III interpeak latencies, bilaterally and LIP I-V in the left ear.


CONCLUSIONS
in the NIHL group, besides sensorial injury, changes in BEAP latencies suggest an early functional injury of the first auditory pathway afferent neuron.
Santos
Adriana Silveira
AS
Medical Sciences School, Sta. Casa de S. Paulo.
Castro Júnior
Ney de
Nd
D000328:Adult; D001334:Automobile Driving; D016022:Case-Control Studies; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D006317:Hearing Loss, Noise-Induced / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D009623:Noise, Occupational / Q000009:adverse effects*; D009624:Noise, Transportation / Q000009:adverse effects*; D009784:Occupational Diseases / Q000209:etiology / Q000503:physiopathology*; D011446:Prospective Studies