On the influence of acoustical probe impedance on evoked otoacoustic emissions

Using two different probes representing different acoustical impedances, simultaneously evoked otoacoustic emissions, thresholds in quiet, and delayed evoked emissions were measured in the frequency region of 900 to 1100 Hz for one subject who has extremely large emissions at these frequencies. All data show that the sound pressure produced in the closed ear canal clearly depends on two contributions, that of the activity of the inner ear, and that of the acoustical impedance of the probe. These effects can be simulated in an analog model of peripheral preprocessing.