Comparison of Parameters in e-OAE Recorded by Two Testing Apparatus

Abstract

Evoked otoacoustic emission (e-OAE) elicited by click sounds was recorded by two testing apparatus (ILO88: A and laboratory-built e-OAE testing system using probe K-2: B) and parameters in e-OAE recorded by both apparatus were compared. The subjects were 60 ears with type A tympanogram from 30 normal hearing persons. Almost the same distribution of intersubject difference and interaural difference was found in parameters of e-OAE recorded by both apparatus (e-OAE pseudothreshold recorded by apparatus B and total echo power (TEP) and highest peak power (HPP) in e-OAE recorded by apparatus A). There were high negative correlations between intersubject difference of e-OAE pseudothreshold in B and that of TEP and HPP in A. However, the correlation coefficients between interaural difference of TEP and HPP in A and that of e-OAE pseudothreshold in B showed lower values because of the small interaural difference of parameters in both testing apparatus.
Based upon these results, we concluded that the parameters such as TEP and HPP in apparatus A could be the clinically useful tool to investigate the function of cochlear micromechanics.
Following three criteria for e-OAE present in ILO88 were proposed. (1) Visual detection of e-OAE waveform. (2) Clear cross power spectrum (white part) in FFT pictures. (3) The ‘Repro’ figure is greater than 40%.