Contralateral acoustic stimulation alters the magnitude and phase of distortion product otoacoustic emissions

Ryan Deeter, Rebekah Abel, Lauren Calandruccio, Sumitrajit Dhar*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)


Activation of medial olivocochlear efferents through contralateral acoustic stimulation (CAS) has been shown to modulate distortion product otoacoustic emission (DPOAE) level in various ways (enhancement, reduction, or no change). The goal of this study was to investigate the effect of a range of CAS levels on DPOAE fine structure. The 2 f1 - f2 DPOAE was recorded (f2 / f1 =1.22, L1 =55 dB, and L2 =40 dB) from eight normal-hearing subjects, using both a frequency-sweep paradigm and a fixed frequency paradigm. Contamination due to the middle ear muscle reflex was avoided by monitoring the magnitude and phase of a probe in the test ear and by monitoring DPOAE stimulus levels throughout testing. Results show modulations in both level and frequency of DPOAE fine structure patterns. Frequency shifts observed at DPOAE level minima could explain reports of enhancement in DPOAE level due to efferent activation. CAS affected the magnitude and phase of the DPOAE component from the characteristic frequency region to a greater extent than the component from the overlap region between the stimulus tones. This differential effect explains the occasional enhancement observed in DPOAE level as well as the frequency shift in fine structure patterns.

Original languageEnglish
Pages (from-to)2413-2424
Number of pages12
JournalJournal of the Acoustical Society of America
Issue number5
Publication statusPublished - 2009
Externally publishedYes


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