gms | German Medical Science

Distortion product otoacoustic emissions (DPOAE) are measured in clinical routine up to a frequency of 8 kHz. The intensity of the component at 2 f1–f2 is used as an indicator of cochlea status. Although high frequencies DPOAE have a high potential, they are not being used because of their poor signal to noise ratio (SNR). A new method of measuring DPOAE signal level based on windowed power spectral density estimation of stochastic signals and filtering theory is presented. We used this novel algorithm to measure and extract the two tone stimuli and all DPOAE signals, which are produced from the nonlinear intermodulation between the stimuli and the cochlea. In this study, we recorded DPOAE signals from 0.5 kHz to 18 kHz in 10 young normal hearing adults (22 to 27 years). For the measurement we used a DPOAE probe from the interacoustics device ILO 092. The DPOAE signal with the relation 2 f1–f2 was recorded with an appropriate SNR in the frequency range from 500 Hz to 18 kHz. In the frequency rang up to 2.5 kHz we found a good SNR in the frequency relation 3 f1 and 3 f2 and in high frequencies over 10 kHz are elicited DPOAE signals with a higher SNR in the frequency relation of f2–f1. For clinical applications, we use this objective technique for monitoring patients who undergo a potentially ototoxic therapy.