One source for distortion product otoacoustic emissions generated by low- and high-level primaries

Andrei N. Lukashkin, Victoria A. Lukashkina, Ian J. Russell

    Research output: Contribution to journalArticlepeer-review


    Distortion product otoacoustic emissions (DPOAE) elicited by tones below 60-70 dB sound pressure level (SPL) are significantly more sensitive to cochlear insults. The vulnerable, low-level DPOAE have been associated with the postulated active cochlear process, whereas the relatively robust high-level DPOAE component has been attributed to the passive, nonlinear macromechanical properties of the cochlea. However, it is proposed that the differences in the vulnerability of DPOAEs to high and low SPLs is a natural consequence of the way the cochlea responds to high and low SPLs. An active process boosts the basilar membrane (BM) vibrations, which are attenuated when the active process is impaired. However, at high SPLs the contribution of the active process to BM vibration is small compared with the dominating passive mechanical properties of the BM. Consequently, reduction of active cochlear amplifieation will have greatest effect on BM vibrations and DPOAEs at low SPLs. To distinguish between the two sources and the single source hypotheses we analyzed the level dependence of the notch and corresponding phase discontinuity in plots of DPOAE magnitude and phase as functions of the level of the primaries. In experiments where furosemide was used to reduce cochlear amplification, an upward shift of the notch supports the conclusion that both the low- and high-level DPOAEs are generated by a single source, namely a nonlinear amplifier with saturating I10 characteristic.

    Original languageEnglish
    Pages (from-to)2740-2748
    Number of pages9
    JournalJournal of the Acoustical Society of America
    Issue number6
    Publication statusPublished - 23 Jul 2002


    Dive into the research topics of 'One source for distortion product otoacoustic emissions generated by low- and high-level primaries'. Together they form a unique fingerprint.

    Cite this