The effects of broadband elicitor duration on a psychoacoustic measure of cochlear gain reduction

Physiological and psychoacoustic studies of the medial olivocochlear reflex (MOCR) in humans have often relied on long duration elicitors (>100 ms). This is largely due to previous research using otoacoustic emissions (OAEs) that found multiple MOCR time constants, including time constants in the 100s of milliseconds, when elicited by broadband noise. However, the effect of the duration of a broadband noise elicitor on similar psychoacoustic tasks is currently unknown. The current study measured the effects of ipsilateral broadband noise elicitor duration on psychoacoustic gain reduction estimated from a forward-masking paradigm. Analysis showed that both masker type and elicitor duration were significant main effects, but no interaction was found. Gain reduction time constants were similar to 46 ms for the masker present condition and similar to 78 ms for the masker absent condition (ranging from similar to 29 to 172 ms), both similar to the fast time constants reported in the OAE literature (70-100 ms). Maximum gain reduction was seen for elicitor durations of similar to 200 ms. This is longer than the 50-ms duration which was found to produce maximum gain reduction with a tonal on-frequency elicitor. Future studies of gain reduction may use 150-200 ms broadband elicitors to maximally or near-maximally stimulate the MOCR. (C) 2023 Acoustical Society of America.

Automated summary

Physiological and psychoacoustic studies have used long duration elicitors (>100 ms) to investigate the medial olivocochlear reflex (MOCR) in humans. Previous research using otoacoustic emissions (OAEs) found time constants in the range of 100s of milliseconds when elicited by broadband noise. However, the effect of broadband noise duration on psychoacoustic tasks is currently unknown.