Is Characteristic Frequency Limiting Real-Time Electrocochleography During Cochlear Implantation?

Autor: Amit Walia, Matthew A. Shew, Shannon M. Lefler, Dorina Kallogjeri, Cameron C. Wick, Timothy A. Holden, Nedim Durakovic, Amanda J. Ortmann, Jacques A. Herzog, Craig A. Buchman
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Frontiers in Neuroscience, Vol 16 (2022)
Druh dokumentu: article
ISSN: 1662-453X
DOI: 10.3389/fnins.2022.915302
Popis: ObjectivesElectrocochleography (ECochG) recordings during cochlear implantation have shown promise in estimating the impact on residual hearing. The purpose of the study was (1) to determine whether a 250-Hz stimulus is superior to 500-Hz in detecting residual hearing decrement and if so; (2) to evaluate whether crossing the 500-Hz tonotopic, characteristic frequency (CF) place partly explains the problems experienced using 500-Hz.DesignMultifrequency ECochG comprising an alternating, interleaved acoustic complex of 250- and 500-Hz stimuli was used to elicit cochlear microphonics (CMs) during insertion. The largest ECochG drops (≥30% reduction in CM) were identified. After insertion, ECochG responses were measured using the individual electrodes along the array for both 250- and 500-Hz stimuli. Univariate regression was used to predict whether 250- or 500-Hz CM drops explained low-frequency pure tone average (LFPTA; 125-, 250-, and 500-Hz) shift at 1-month post-activation. Postoperative CT scans were performed to evaluate cochlear size and angular insertion depth.ResultsFor perimodiolar insertions (N = 34), there was a stronger linear correlation between the largest ECochG drop using 250-Hz stimulus and LFPTA shift (r = 0.58), compared to 500-Hz (r = 0.31). The 250- and 500-Hz CM insertion tracings showed an amplitude peak at two different locations, with the 500-Hz peak occurring earlier in most cases than the 250-Hz peak, consistent with tonotopicity. When using the entire array for recordings after insertion, a maximum 500-Hz response was observed 2–6 electrodes basal to the most-apical electrode in 20 cases (58.9%). For insertions where the apical insertion angle is >350 degrees and the cochlear diameter is
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