title: Alteration of distortion product otoacoustic emission input/output functions in subjects with a previous history of middle ear dysfunction.
abstract: BACKGROUND
  The aim of this study was to investigate the effects of sub-clinical alterations on the amplitudes and slopes of the DPOAE input-output responses from subjects with previous history of middle ear dysfunction.
  
  
  METHODS
  The study included 15 subjects with and 15 subjects without a history of otitis media in the last 10 years. All participants were assessed with acoustic immittance, pure-tone audiometry, and DPOAEs. For the later, I/O functions and I/O slopes were estimated at 1501, 2002, 3174, 4004 and 6384 Hz.
  
  
  RESULTS
  No statistically significant differences were found between the 2 groups in terms of behavioral thresholds. The group with a previous history of middle ear dysfunction presented significantly lower mean DPOAE amplitudes at 2002, 3174 and 4004 Hz. In terms of DPOAE slopes, no statistically significant differences were observed at the tested frequencies, except at 3174 Hz.
  
  
  CONCLUSIONS
  Middle ear pathologies can produce subclinical alterations that are undetectable with traditional pure-tone audiometry. The data from the present study show that reduced amplitude DPOAEs are associated with a previous history of middle ear complications. The corresponding DPOAE slopes were affected at only 1 tested frequency, suggesting that the cochlear non-linearity is preserved. Considering these results, it remains to be elucidated to what degree the DPOAE amplitude attenuation interferes with higher-order auditory tasks.
authors.affiliation: FMUSP--University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: Ualace
authors.initials: U
authors.lastname: De P Campos
authors.forename: Seisse G
authors.initials: SG
authors.lastname: Sanches
authors.forename: Stavros
authors.initials: S
authors.lastname: Hatzopoulos
authors.forename: Renata M M
authors.initials: RM
authors.lastname: Carvallo
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Kochanek
authors.forename: Henryk
authors.initials: H
authors.lastname: Skarżyński
mesh_terms: D001301:Audiometry, Pure-Tone; D001519:Behavior / Q000502:physiology; D016022:Case-Control Studies; D004432:Ear, Middle / Q000503:physiopathology*; D006801:Humans; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D010469:Perceptual Distortion / Q000502:physiology*; D059629:Signal-To-Noise Ratio; D055815:Young Adult