ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

5pPP10. Modeling distortion product otoacoustic emission fine structure in humans.

Carrick L. Talmadge

Arnold Tubis

Pawal Piskorski

Dept. of Phys., Purdue Univ., West Lafayette, IN 47907

Glenis R. Long

Purdue Univ., West Lafayette, IN 47907

The presence of fine structure in distortion product otoacoustic emissions (DPOAEs) in humans and other species provides important clues concerning the underlying mechanisms which give rise to this structure. Recent experimental findings of our group indicate that (i) synchronous evoked emissions, hearing threshold microstructure, and the fine structure of DPOAES in each ear appear to correspond, (ii) the fine structure of higher-order DPOAEs, i.e., f1-n(F2-f1), n>2 depends on the DPOAE frequency, and (iii) DPOAEs with n<-1 do not have well-formed fine structure. These data will be used to contrast and compare two distinct models of DPOAE generation, one in which the fine structure arises from the interactions in the strong overlap region of the f1 and f2 activity patterns (near the f2 tonotopic place), and one in which the fine structure arises from reflections of the distortion product near its tonotopic location. The data strongly favor the later model.