4pPP7. On the relation of distortion product and transient evoked emission spectral fine structure.

Session: Thursday Afternoon, May 16

Author: Stefan Uppenkamp
Author: Manfred Mauermann
Author: Birger Kollmeier
Location: AG Medizinische Physik, Fachbereich Physik, Univ. Oldenburg, D-26111 Oldenburg, Germany


Both distortion product emissions and transiently evoked emissions typically exhibit an individual fine structure, which seems to be linked to the fine structure of threshold in quiet observable in many normal hearing subjects. However, the recording paradigm for both experiments is rather different. Narrow-band distortion product emissions are detectable during continuous stimulation with two sinusoids. They represent the nonlinear interaction of the two tones in a stationary condition. Transient evoked emissions on the other hand may be interpreted as a type of impulse response of a nonlinear system. The frequency specificity is comparatively low. The interrelation of both types of emissions is not completely understood until now. To test the hypothesis of a common origin, patterns of spectral fine structure of DPOAE and TEOAE results from normal hearing subjects are compared. In addition, the influence of suppressor tones is investigated in both experiments. Results will be discussed in connection to current ideas about wave-fixed and place-fixed generation of emissions along the cochlear partition.

from ASA 131st Meeting, Indianapolis, May 1996