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

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 eva...

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Main Authors: 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
Format: Article
Language:English
Published: Frontiers Media S.A. 2022-07-01
Series:Frontiers in Neuroscience
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fnins.2022.915302/full
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author 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
author_facet 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
author_sort Amit Walia
collection DOAJ
description 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 <9.5 mm, the maximum 500-Hz ECochG response may occur at the non-apical most electrode. For lateral wall insertions (N = 14), the maximum 250- and 500-Hz CM response occurred at the most-apical electrode in all but one case.ConclusionUsing 250-Hz stimulus for ECochG feedback during implantation is more predictive of hearing preservation than 500-Hz. This is due to the electrode passing the 500-Hz CF during insertion which may be misidentified as intracochlear trauma; this is particularly important in subjects with smaller cochlear diameters and deeper insertions. Multifrequency ECochG can be used to differentiate between trauma and advancement of the apical electrode beyond the CF.
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spelling doaj.art-484f464e6b084605a8ff6a5b05098e5b2022-12-22T00:45:10ZengFrontiers Media S.A.Frontiers in Neuroscience1662-453X2022-07-011610.3389/fnins.2022.915302915302Is Characteristic Frequency Limiting Real-Time Electrocochleography During Cochlear Implantation?Amit WaliaMatthew A. ShewShannon M. LeflerDorina KallogjeriCameron C. WickTimothy A. HoldenNedim DurakovicAmanda J. OrtmannJacques A. HerzogCraig A. BuchmanObjectivesElectrocochleography (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 <9.5 mm, the maximum 500-Hz ECochG response may occur at the non-apical most electrode. For lateral wall insertions (N = 14), the maximum 250- and 500-Hz CM response occurred at the most-apical electrode in all but one case.ConclusionUsing 250-Hz stimulus for ECochG feedback during implantation is more predictive of hearing preservation than 500-Hz. This is due to the electrode passing the 500-Hz CF during insertion which may be misidentified as intracochlear trauma; this is particularly important in subjects with smaller cochlear diameters and deeper insertions. Multifrequency ECochG can be used to differentiate between trauma and advancement of the apical electrode beyond the CF.https://www.frontiersin.org/articles/10.3389/fnins.2022.915302/fullcochlear implantationelectrocochleographyhearing preservationmultifrequency electrocochleographycharacteristic frequency250 Hz vs. 500 Hz
spellingShingle 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
Is Characteristic Frequency Limiting Real-Time Electrocochleography During Cochlear Implantation?
Frontiers in Neuroscience
cochlear implantation
electrocochleography
hearing preservation
multifrequency electrocochleography
characteristic frequency
250 Hz vs. 500 Hz
title Is Characteristic Frequency Limiting Real-Time Electrocochleography During Cochlear Implantation?
title_full Is Characteristic Frequency Limiting Real-Time Electrocochleography During Cochlear Implantation?
title_fullStr Is Characteristic Frequency Limiting Real-Time Electrocochleography During Cochlear Implantation?
title_full_unstemmed Is Characteristic Frequency Limiting Real-Time Electrocochleography During Cochlear Implantation?
title_short Is Characteristic Frequency Limiting Real-Time Electrocochleography During Cochlear Implantation?
title_sort is characteristic frequency limiting real time electrocochleography during cochlear implantation
topic cochlear implantation
electrocochleography
hearing preservation
multifrequency electrocochleography
characteristic frequency
250 Hz vs. 500 Hz
url https://www.frontiersin.org/articles/10.3389/fnins.2022.915302/full
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