Establishing Reproducibility and Correlation of Cochlear Microphonic Amplitude to Implant Electrode Position Using Intraoperative Electrocochleography and Postoperative Cone Beam Computed Tomography

Soulby, Andrew; Connor, Steve; Jiang, Dan; Nunn, Terry; Boyle, Patrick; Pai, Irumee

doi:10.1097/aud.0000000000001010

Cited by 4 publications

(6 citation statements)

References 40 publications

(54 reference statements)

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“…Intracochlear ECochG responses were acquired at a sampling rate of 9280 Hz from the CI's most apical electrode. The details of the recording method and measurement setup are described by Soulby et al (2021) . For acoustic stimulation, a tone burst with an intensity between 100 and 115 dB HL (113.5 and 128.5 dB SPL) and a duration of 50 ms, including 5 ms linear onset and offset ramps, was used.…”

Section: Methodsmentioning

confidence: 99%

“…In total, recordings from 8 out of 10 subjects with stepwise insertions and 10 out of 12 subjects with continuous insertions included in Zurich, 13 out of 17 subjects included in Oslo, and 9 out of 13 subjects included in London were considered valid, leading to the inclusion of data from 40 subjects for classification. The data from London and recordings from 6 out of 10 subjects with stepwise insertions from Zurich were previously published ( Sijgers et al, 2021 ; Soulby et al, 2021 ).…”

Section: Methodsmentioning

confidence: 99%

“…When using a 500 Hz tone burst for acoustic stimulation, DIF response amplitude decreases unrelated to cochlear trauma often occur near full insertion. They are likely caused by destructive interferences of hair cells from the 500 Hz resonance location and more basal hair cells since the response generators from these locations move out of phase ( Giardina et al, 2019 ; Soulby et al, 2021 ). Such atraumatic amplitude decreases are often accompanied by phase shifts and harmonic distortions ( Kohllöffel, 1970 ; Soulby et al, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

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Classification of Acoustic Hearing Preservation After Cochlear Implantation Using Electrocochleography

Sijgers,

Sorensen,

Soulby

et al. 2023

Trends in Hearing

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The objective to preserve residual hearing during cochlear implantation has recently led to the use of intracochlear electrocochleography (ECochG) as an intraoperative monitoring tool. Currently, a decrease in the amplitude of the difference between responses to alternating-polarity stimuli (DIF response), predominantly reflecting the hair cell response, is used for providing feedback. Including other ECochG response components, such as phase changes and harmonic distortions, could improve the accuracy of surgical feedback. The objectives of the present study were (1) to compare simultaneously recorded stepwise intracochlear and extracochlear ECochG responses to 500 Hz tone bursts, (2) to explore patterns in features extracted from the intracochlear ECochG recordings relating to hearing preservation or hearing loss, and (3) to design support vector machine (SVM) and random forest (RF) classifiers of acoustic hearing preservation that treat each subject as a sample and use all intracochlear ECochG recordings made during electrode array insertion for classification. Forty subjects undergoing cochlear implant (CI) surgery at the Oslo University Hospital, St. Thomas’ Hearing Implant Centre, or the University Hospital of Zurich were prospectively enrolled. In this cohort, DIF response amplitude decreases did not relate to postoperative acoustic hearing preservation. Exploratory analysis of the feature set extracted from the ECochG responses and preoperative audiogram showed that the features were not discriminative between outcome classes. The SVM and RF classifiers that were trained on these features could not distinguish cases with hearing loss and hearing preservation. These findings suggest that hearing loss following CI surgery is not always reflected in intraoperative ECochG recordings.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Classification of Acoustic Hearing Preservation After Cochlear Implantation Using Electrocochleography

Sijgers,

Sorensen,

Soulby

et al. 2023

Trends in Hearing

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“…In both studies, neither 250-Hz acoustic stimulus nor multifrequency ECochG was used during the insertion; both used 500-Hz acoustic stimulus only. Soulby et al (2021) showed the relationship between changes in the intraoperative ECochG CM 500-Hz response both on the electrode sweep and during insertion correlated with postoperative behavioral audiogram thresholds when using the SlimJ electrode array. This is consistent with the findings here as these short slim lateral wall electrodes do not cross the 500-Hz CF place in most cochleae.…”

Section: -Vs 500-hz Stimulus -Real-time Electrocochleography For Hear...mentioning

confidence: 98%

“…Generally, as the array approaches the apex of the cochlea, the CM amplitude gradually increases since the electrode is theorized to approach the characteristic frequency (CF) place for 500-Hz. If there is a drop in CM amplitude during the insertion, this may be related to (1) electrode-basilar membrane contact resulting in reversible or irreversible intracochlear trauma, (2) advancement of the mostapical electrode beyond the CF place in the cochlea, or (3) exceeding the intracochlear source generator with inconsistent hair cells throughout the cochlea (Campbell et al, 2017;Saoji et al, 2019;Soulby et al, 2021). When a single stimulus frequency of 500-Hz is used for monitoring during the insertion, there is no way of determining which of the above causes resulted in the decreased CM amplitude, which makes it challenging to provide clinically useful feedback intraoperatively.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

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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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Robotics, automation, active electrode arrays, and new devices for cochlear implantation: A contemporary review

et al. 2022

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Establishing Reproducibility and Correlation of Cochlear Microphonic Amplitude to Implant Electrode Position Using Intraoperative Electrocochleography and Postoperative Cone Beam Computed Tomography

Abstract: Supplemental Digital Content is available in the text.

Cited by 4 publications

References 40 publications

Classification of Acoustic Hearing Preservation After Cochlear Implantation Using Electrocochleography

Classification of Acoustic Hearing Preservation After Cochlear Implantation Using Electrocochleography

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

Robotics, automation, active electrode arrays, and new devices for cochlear implantation: A contemporary review

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