Auditory enhancement refers to the perceptual phenomenon that a target sound is heard out more readily from a background sound if the background is presented alone first. Here we used stimulus-frequency otoacoustic emissions (SFOAEs) to test the hypothesis that activation of the medial olivocochlear efferent system contributes to auditory enhancement effects. The SFOAEs were used as a tool to measure changes in cochlear responses to a target component and the neighboring components of a multitone background between conditions producing enhancement and conditions producing no enhancement. In the “enhancement” condition, the target and multitone background were preceded by a precursor stimulus with a spectral notch around the signal frequency; in the control (no-enhancement) condition, the target and multitone background were presented without the precursor. In an experiment using a wideband multitone stimulus known to produce significant psychophysical enhancement effects, SFOAEs showed no changes consistent with enhancement, but some aspects of the results indicated possible contamination of the SFOAE magnitudes by the activation of the middle-ear-muscle reflex. The same SFOAE measurements performed using narrower-band stimuli at lower sound levels also showed no SFOAE changes consistent with either absolute or relative enhancement despite robust psychophysical enhancement effects observed in the same listeners with the same stimuli. The results suggest that cochlear efferent control does not play a significant role in auditory enhancement effects.
|Original language||English (US)|
|Number of pages||17|
|Journal||JARO - Journal of the Association for Research in Otolaryngology|
|State||Published - Oct 22 2015|
Bibliographical noteFunding Information:
This study was supported by grant R01 DC 010374 from the National Institutes of Health, awarded to author MW. The authors thank two anonymous reviewers for their helpful comments on the previous version of the manuscript.
© 2015, Association for Research in Otolaryngology.
- auditory enhancement
- cochlear gain
- medial olivocochlear reflex