A nonlinear version of the stimulus-frequency otoacoustic emission (SFOAE) was measured using stimulus waveforms similar to those used for behavioral overshoot. Behaviorally, the seven listeners were as much as 11. dB worse at detecting a brief tonal signal (4.0. kHz, 10. ms in duration) when it occurred soon after the onset of a wideband masking noise (0.1-6.0. kHz; 400. ms in duration) than when it was delayed by about 200. ms, and the nonlinear SFOAE measure exhibited a similar effect. When either lowpass (0.1-3.8. kHz) or bandpass noise (3.8-4.2. kHz) was used instead of the wideband noise, the physiological and behavioral measures again were similar. When a highpass noise (4.2-6.0. kHz) was used, the physiological and behavioral measures both showed no overshoot-like effect for five of the subjects. The physiological response to the tone decayed slowly after the termination of the noise, much like the time course of resetting for behavioral overshoot. One subject exhibited no overshoot behaviorally even though his cochlear responses were like those of the other subjects. Overall, the evidence suggests that some basic characteristics of overshoot are obligatory consequences of cochlear function, as modulated by the olivocochlear efferent system.
Bibliographical noteFunding Information:
This work was supported by a research grant awarded to DM by the National Institute on Deafness and other Communication Disorders (NIDCD 00153). Author KPW conducted this and additional research on this topic while working on a Master’s degree at The University of Texas ( Walsh, 2009 ). Early stages of the work were reported at conferences ( Walsh et al., 2008, 2009 ). The work profited greatly from discussions with Drs. C.A. Champlin, E.A. Strickland, M. Wojtczak, and N.F. Viemeister, who also made comments on a preliminary version of this paper. Comments by Dr. D.H. Keefe and an anonymous reviewer were extremely helpful.