Tracing Distortion Product (DP) waves in a cochlear model

Egbert De Boer, Christopher A. Shera, Alfred L. Nuttall

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


In many cases a cochlear model suffices to explain (by simulation) the properties of waves in the cochlea. This is not so in the case of a distortion product (DP) set up by presenting two primary tones to the cochlea. A three-dimensional model predicts, apart from a DP wave traveling in the apical direction, a DP wave that travels from the region of overlap of the two tone patterns towards the stapes - setting the stapes in motion so as to produce an otoacoustic emission at the DP frequency. Experimental research has shown, however, that the actual DP wave in the cochlea appears to travel in the opposite direction, from near the stapes to the overlap region. This feature has been termed "inverted direction of wave propagation" (IDWP). The forward wave could result from an unknown process such as a "hidden source" near the stapes. In the present study we have disproved this notion, by using a one-dimensional model of the cochlea. It is found that both reverse and forward waves are set up by the source of nonlinearity, in the same way as has been published in an earlier work. The present results reveal that IDWP in the data corresponds to the region where the DP wave, originally created as a reverse wave but reflected from the stapes, has received so much amplification that it starts to dominate over the reverse wave. Hence we conclude that IDWP in a one-dimensional model is a direct manifestation of cochlear amplification.

Original languageEnglish (US)
Title of host publicationWhat Fire is in Mine Ears
Subtitle of host publicationProgress in Auditory Biomechanics - Proceedings of the 11th International Mechanics of Hearing Workshop
Number of pages6
StatePublished - 2011
Event11th International Mechanics of Hearing Workshop - What Fire is in Mine Ears: Progress in Auditory Biomechanics - Williamstown, MA, United States
Duration: Jul 16 2011Jul 22 2011

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Other11th International Mechanics of Hearing Workshop - What Fire is in Mine Ears: Progress in Auditory Biomechanics
Country/TerritoryUnited States
CityWilliamstown, MA


  • cochlear model
  • cochlear wave
  • distortion product
  • nonlinearity
  • otoacoustic emission

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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