[Distortion product otoacoustic emissions in normally hearing young humans].

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.