title: Analysis of distortion product otoacoustic emission spectra in normal-hearing adults.
abstract: OBJECTIVE
  To evaluate the ability of distortion product otoacoustic emission (DPOAE) spectral characteristics to distinguish between ears with variable hearing sensitivity within the normal range.
  
  
  METHODS
  Distortion product grams (DP-grams) were acquired with primary tones decremented in 1/8-octave steps and primary-tone levels presented at 65 dB SPL (L1) and 45 dB SPL (L2) across an f2 frequency range of 842-7996 Hz from 22 normal-hearing adults (44 ears). Hearing thresholds of ears classified in Group A (n = 22) were better than ears classified in Group B (n = 22). Examined parameters of the DP-grams included spectral peak occurrence, peak height, peak width, and DPOAE levels. Analyses of variance were conducted to determine whether DP-gram parameters differed between Group A and Group B.
  
  
  RESULTS
  For the low-resolution DP-grams examined in this study, no significant between-group differences in peak occurrence, peak height, and peak width were observed. DPOAE levels were significantly higher in ears classified in Group A compared with ears classified in Group B in individuals with symmetrical hearing.
  
  
  CONCLUSIONS
  Although spectral peaks are evident in DP-grams acquired with low resolution of the primary tones, DPOAE levels are more effective in distinguishing ears with greater hearing sensitivity from less sensitive ears.
authors.affiliation: The University of Memphis - School of Audiology and Speech-Language Pathology, 807 Jefferson Avenue, Memphis, TN 38015, USA. sbhagat@memphis.edu
authors.forename: Shaum
authors.initials: S
authors.lastname: Bhagat
mesh_terms: D000328:Adult; D001309:Auditory Threshold; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted; D012984:Software; D055815:Young Adult