title: Influence of the stimulus presentation rate on medial olivocochlear system assays.
abstract: Click evoked otoacoustic emissions (CEOAEs) are commonly used both in research and clinics to assay the medial olivocochlear system (MOC). Clicks presented at rates >50 Hz in the contralateral ear have previously been reported to evoke contralateral MOC activity. However, in typical MOC assays, clicks are presented in the ipsilateral ear in conjunction with MOC elicitor (noise) in the contralateral ear. The effect of click rates in such an arrangement is currently unknown. A forward masking paradigm was used to emulate typical MOC assays to elucidate the influence of ipsilateral click presentation rates on MOC inhibition of CEOAEs in 28 normal hearing adults. Influence of five click rates (20.83, 25, 31.25, 41.67, and 62.5 Hz) presented at 55 dB peSPL was tested. Results indicate that click rates as low as 31.25 Hz significantly enhance contralateral MOC inhibition, possibly through the activation of ipsilateral and binaural MOC neurons with potential contributions from the middle ear muscle reflex. Therefore, click rates ≤25 Hz are recommended for use in MOC assays, at least for 55 dB peSPL click level.
authors.affiliation: National Centre for Audiology, Western University, London, Ontario N6G 1H1, Canada.
authors.forename: Sriram
authors.initials: S
authors.lastname: Boothalingam
authors.affiliation: National Centre for Audiology, Western University, London, Ontario N6G 1H1, Canada.
authors.forename: David W
authors.initials: DW
authors.lastname: Purcell