title: [Distortion product otoacoustic emissions in normally hearing young humans].
abstract: OBJECTIVE
  To investigate the basic properties of distortion product otoacoustic emissions (DPOAE) in normally hearing subjects of China.
  
  
  METHODS
  DPOAE "audiogram" (DP-gram) and input/output functions (I/O functions) were recorded from 24 normally hearing young humans with Celesta-503 cochlear emissions analyzer.
  
  
  RESULTS
  The prevalence of DPOAE was 100% ranging in frequency from 500 to 8,000 Hz, with respect to the geometric means of f1 and f2 stimuli. The mean DP-gram had two peaks at about 1,000 Hz and 6,000 Hz and a dip at about 3,000 Hz. The higher amplitude of DPOAE was recorded at about 3,000 Hz when using unequal primary-tone levels (L1 > L2). The mean thresholds of DPOAE were between 25 and 40 dB SPL. The thresholds of DPOAE decreased with increasing primary-tone frequencies. The I/O slopes were higher at about peak freqencies than at other frequencies. For all the results of DPOAE in left and right ears, there were no apparent differences by statistics.
  
  
  CONCLUSIONS
  By systematical studies of the properties of DPOAE in normally hearing ears of Chinese subjects, this paper provides basic reference data for clinical application of DPOAE.
authors.affiliation: PUMC Hospital, CAMS and PUMC, Beijing 100730.
authors.forename: H
authors.initials: H
authors.lastname: Dan
authors.forename: D
authors.initials: D
authors.lastname: Ni
authors.forename: F
authors.initials: F
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous; D012016:Reference Values