title: Otoacoustic emissions in normal-hearing workers exposed to different noise doses.
abstract: BACKGROUND
  The otoacoustic emission test is useful in monitoring hearing changes not yet detectable in pure-tone audiometry, as well as in monitoring cochlear damage caused by exposure to noise.
  
  
  OBJECTIVE
  To evaluate distortion product otoacoustic emissions in normal-hearing workers exposed to different occupational noise doses.
  
  
  METHODS
  This is a cohort prospective study performed in metalworking industries, in which normal-hearing workers were assessed by being divided into three different groups: GI not exposed, GII sporadically exposed and GIII often exposed to occupational noise.
  
  
  RESULTS
  Otoacoustic emission alterations were found in groups II and III bilaterally. Both in the amplitude and in the signal/noise ratio it was observed that as higher was the frequency, worse were the results of GII and GIII (p > 0.001), and the greater the exposure dose is, the lower the averages found in otoacoustic emission.
  
  
  CONCLUSIONS
  The otoacoustic emissions are worse in the exposed groups compared to the unexposed group and the greater are the noise dose, worse are the results.
authors.forename: Marlene Escher
authors.initials: ME
authors.lastname: Boger
authors.forename: André Luiz Lopes
authors.initials: AL
authors.lastname: Sampaio
authors.forename: Carlos Augusto Costa Pires de
authors.initials: CA
authors.lastname: Oliveira
mesh_terms: D001301:Audiometry, Pure-Tone; D006317:Hearing Loss, Noise-Induced; D006801:Humans; D009623:Noise, Occupational; D017084:Otoacoustic Emissions, Spontaneous; D011446:Prospective Studies