Modification of DPOAE fine structure stemming from changes in outer and middle ear function

Abstract

High resolution DPOAE fine structure was evaluated when the output impedance of the cochlea was modified by: (1) Changes in outer ear volume, due to accumulation of cerumen, which does not modify input impedance. (2) Manipulation of middle ear pressure and scarring of the tympanic membrane (which modify both input and output impedance). At high primary levels a wider and deeper DPOAE structure combined with (and sometimes dominated) DPOAE level fine structure. The group delay was also modified, sometimes giving rise to negative group delay. The data can be modeled by assuming that the increased impedance at the oval widow produces reflections back into the cochlea which can be re-reflected. © 2011 American Institute of Physics.