Cochlear microphonic latency predicts outer hair cell function in animal models and clinical populations.

Bester, Christofer; Weder, Stefan; Collins, Aaron; Dragovic, Adrian; Brody, Kate; Hampson, Amy; O'Leary, Stephen (2020). Cochlear microphonic latency predicts outer hair cell function in animal models and clinical populations. Hearing research, 398, p. 108094. Elsevier 10.1016/j.heares.2020.108094

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As recently reported, electrocochleography recorded in cochlear implant recipients showed reduced amplitude and shorter latency in patients with more severe high-frequency hearing loss compared with those with some residual hearing. As the response is generated primarily by receptor currents in outer hair cells, these variations in amplitude and latency may indicate outer hair cell function after cochlear implantation. We propose that an absence of latency shift when the cochlear microphonic is measured on two adjacent electrodes indicates an absence or dysfunction of outer hair cells between these electrodes. We test this preclinically in noise deafened guinea pigs (2 h of a 124 dB HL, 16-24 kHz narrow-band noise), and clinically, in electrocochleographic recordings made in cochlear implant recipients immediately after implantation. We found that normal hearing guinea pigs showed a progressive increase in latency from basal to apical electrodes. In contrast, guinea pigs with significantly elevated high-frequency hearing thresholds showed no change in cochlear microphonic latency measured on basal electrodes (located approximately at the 16-24 kHz location in the cochlea).. In the clinical cohort, a significant negative correlation existed between cochlear microphonic latency shifts and hearing thresholds at 1-, 2-, & 4 kHz when tested on electrodes located at the relevant cochlear tonotopic place. This reduction in latency shift was such that patients with no measurable hearing also had no detectable latency shift (place assessed by CT scan, r's of -.70 to -.83). These findings suggest that electrocochleography can be used as a diagnostic tool to detect cochlear regions with functioning hair cells, which may be important for defining cross-over point for electro-acoustic stimulation.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Ear, Nose and Throat Disorders (ENT)

UniBE Contributor:

Weder, Stefan

Subjects:

600 Technology > 610 Medicine & health

ISSN:

0378-5955

Publisher:

Elsevier

Language:

English

Submitter:

Stefan Weder

Date Deposited:

19 Jan 2021 15:10

Last Modified:

24 Jan 2021 03:00

Publisher DOI:

10.1016/j.heares.2020.108094

PubMed ID:

33099252

Uncontrolled Keywords:

Auditory nerve neurophonic Cochlear microphonic Electrocochleography Intraoperative monitoring Sensorineural hearing loss

BORIS DOI:

10.48350/150352

URI:

https://boris.unibe.ch/id/eprint/150352

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