Seminars in Hearing Research at Purdue (SHRP)

Date: Thursday, March 3, 2022

Time: 10:30 – 11:20 am

Location: LYLE 1150

Title: A Comparison of Gain Reduction Estimated From Behavioral Measures and Various Transient-Evoked Otoacoustic Emission Measures as a Function of Broadband Elicitor Duration 

Speaker: William Salloom, PhD candidate, PULSe program (Strickland lab)

Abstract:  One mechanism that may support the broad dynamic range in hearing is the medial olivocochlear reflex (MOCR), a bilateral feedback loop at the level of the brainstem that can adjust the gain of the cochlear amplifier. Much of the previous physiological MOCR research has used long broadband noise elicitors. In behavioral measures of gain reduction, a fairly short elicitor has been found to be maximally effective for an on-frequency, tonal elicitor. However, the effect of the duration of broadband noise elicitors on behavioral tasks is unknown. Additionally, MOCR effects measured using otoacoustic emissions (OAEs), have not consistently shown a positive correlation with behavioral gain reduction tasks. This finding seems counterintuitive if both measurements share a common generation mechanism. This lack of a positive correlation may be due to different methodologies being utilized for the OAE and behavioral tasks, and/or due to the analysis techniques not being optimized to observe a relationship. In the current study, we explored the effects of ipsilateral broadband noise elicitor duration both physiologically and behaviorally in the same subjects, using a forward-masking paradigm. TEOAE measures included the change in magnitude, or in magnitude and phase, for different frequency analysis bands. For the same subjects, a psychoacoustic forward-masking paradigm was used to measure the effects of the elicitor on masking by an off-frequency masker for a 2-kHz signal, and for the effect of the elicitor on a signal with 20 ms of silence replacing the masker. The goal is to determine how duration of a broadband MOCR elicitor affects cochlear gain physiologically and perceptually, and if there is a relationship between these measures. The current study highlights the importance of choosing appropriate methodology used in estimating MOCR strength, particularly with OAEs.

Zoom Info:

https://purdue-edu.zoom.us/j/93108158900?pwd=RDdTQ0Z4UE9Rb0JUenhjMG1SMkp2QT09

Meeting ID: 931 0815 8900

Passcode: 11501150

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The working schedule for this academic is here:

https://purdue.edu/TPAN/hearing/shrp_schedule

The titles and abstracts of the talks will be added here:

https://purdue.edu/TPAN/hearing/shrp_abstracts