One Click Is Not Enough: Anatomy-Based Fitting in Experienced Cochlear Implant Users

Kurz, Anja; Müller-Graff, Franz-Tassilo; Hagen, Rudolf; Rak, Kristen

doi:10.1097/mao.0000000000003731

Cited by 20 publications

(11 citation statements)

References 9 publications

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“…Either immediately to verify the surgical outcome ( O’Connell et al 2016 ; Rathgeb et al 2019 ) or later in the follow-up to monitor electrode migration ( Dietz et al 2016 ) or to explain parts of the variability in postoperative speech understanding outcomes ( Chakravorti et al 2019 ). In addition, CI audio processor fitting can be personalized to take into account patient anatomy and electrode locations, potentially improving hearing outcomes ( Venail et al 2015 ; Kurz et al 2022 ; Mertens et al 2022 ). The current gold standard for determining intracochlear electrode positions is radiography, which entails radiation exposure, requires dedicated infrastructure, and incurs additional costs, limiting its use in routine clinical practice ( McCollough et al 2015 ).…”

Section: Introductionmentioning

confidence: 99%

Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth

et al. 2023

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Objectives: Reliable determination of cochlear implant electrode positions shows promise for clinical applications, including anatomy-based fitting of audio processors or monitoring of electrode migration during follow-up. Currently, electrode positioning is measured using radiography. The primary objective of this study is to extend and validate an impedance-based method for estimating electrode insertion depths, which could serve as a radiation-free and cost-effective alternative to radiography. The secondary objective is to evaluate the reliability of the estimation method in the postoperative follow-up over several months. Design: The ground truth insertion depths were measured from postoperative computed tomography scans obtained from the records of 56 cases with an identical lateral wall electrode array. For each of these cases, impedance telemetry records were retrieved starting from the day of implantation up to a maximum observation period of 60 mo. Based on these recordings, the linear and angular electrode insertion depths were estimated using a phenomenological model. The estimates obtained were compared with the ground truth values to calculate the accuracy of the model. Results: Analysis of the long-term recordings using a linear mixed-effects model showed that postoperative tissue resistances remained stable throughout the follow-up period, except for the two most basal electrodes, which increased significantly over time (electrode 11: ~10 Ω/year, electrode 12: ~30 Ω/year). Inferred phenomenological models from early and late impedance telemetry recordings were not different. The insertion depth of all electrodes was estimated with an absolute error of 0.9 mm ± 0.6 mm or 22° ± 18° angle (mean ± SD). Conclusions: Insertion depth estimations of the model were reliable over time when comparing two postoperative computed tomography scans of the same ear. Our results confirm that the impedance-based position estimation method can be applied to postoperative impedance telemetry recordings. Future work needs to address extracochlear electrode detection to increase the performance of the method.

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Section: Introductionmentioning

confidence: 99%

Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth

et al. 2023

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“…Consequently, when using the approach of an individualized CC, an accurate prediction of AID before CI surgery is needed (4,7,9). However, apart from the individual cochlear morphology, the AID may be influenced by the electrode array length, the array design (lateral wall vs. perimodiolar), and the surgical approach (round window approach vs. cochleostomy) (28). van der Marel et al (29) showed that more than 81% of the variances in postoperative insertion depths can be explained by the interaction of CDL and surgical insertion.…”

Section: Discussionmentioning

confidence: 99%

Accuracy of Preoperative Cochlear Duct Length Estimation and Angular Insertion Depth Prediction

et al. 2023

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Objective In cochlear implantation with flexible lateral wall electrodes, a cochlear coverage of 70% to 80% is assumed to yield an optimal speech perception. Therefore, fitting the cochlear implant (CI) to the patient’s individual anatomy has gained importance in recent years. For these reasons, the optimal angular insertion depth (AID) has to be calculated before cochlear implantation. One CI manufacturer offers a software that allows to visualize the AID of different electrode arrays. Here, it is hypothesized that these preoperative AID models overestimate the postoperatively measured insertion angle. This study aims to investigate the agreement between preoperatively estimated and postoperatively measured AID. Study Design Retrospective cross-sectional study. Setting Single-center tertiary referral center. Patients Patients undergoing cochlear implantation. Intervention Preoperative and postoperative high-resolution computed tomography (HRCT). Main Outcome Measures The cochlear duct length was estimated by determining cochlear parameters (A value and B value), and the AID for the chosen electrode was (i) estimated by elliptic circular approximation by the software and (ii) measured manually postoperatively by detecting the electrode contacts after insertion. Results A total of 80 HRCT imaging data sets from 69 patients were analyzed. The mean preoperative AID estimation was 662.0° (standard deviation [SD], 61.5°), and the mean postoperatively measured AID was 583.9° (SD, 73.6°). In all cases (100%), preoperative AID estimation significantly overestimated the postoperative determined insertion angle (mean difference, 38.1°). A correcting factor of 5% on preoperative AID estimation dissolves these differences. Conclusions The use of an electrode visualization tool may lead to shorter electrode array choices because of an overestimation of the insertion angle. Applying a correction factor of 0.95 on preoperative AID estimation is recommended.

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“…An association between deeper insertion and frequency discrimination is frequently discussed ( 58 – 60 ). According to Peters et al, the pitch perception with a CI is 1 to 2 octaves lower than the predicted pitch.…”

Section: Discussionmentioning

confidence: 99%

Effect of Cochlear Implant Electrode Insertion Depth on Speech Perception Outcomes: A Systematic Review

Breitsprecher,

Baumgartner,

Brown

et al. 2023

Otology &Amp; Neurotology Open

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Objective: The suitable electrode array choice is broadly discussed in cochlear implantation surgery. Whether to use a shorter electrode length under the aim of structure preservation versus choosing a longer array to achieve a greater cochlear coverage is a matter of debate. The aim of this review is to identify the impact of the insertion depth of a cochlear implant (CI) electrode array on CI users’ speech perception outcomes. Databases Reviewed: PubMed was searched for English-language articles that were published in a peer-reviewed journal from 1997 to 2022. Methods: A systematic electronic search of the literature was carried out using PubMed to find relevant literature on the impact of insertion depth on speech perception. The review was conducted according to the preferred reporting items for systematic reviews and meta-analyses guidelines of reporting. Studies in both, children and adults with pre- or postlingual hearing loss, implanted with a CI were included in this study. Articles written in languages other than English, literature reviews, meta-analyses, animal studies, histopathological studies, or studies pertaining exclusively to imaging modalities without reporting correlations between insertion depth and speech outcomes were excluded. The risk of bias was determined using the “Risk of Bias in Nonrandomized Studies of Interventions” tool. Articles were extracted by 2 authors independently using predefined search terms. The titles and abstracts were screened manually to identify studies that potentially meet the inclusion criteria. The extracted information included: the study population, type of hearing loss, outcomes reported, devices used, speech perception outcomes, insertion depth (linear insertion depth and/or the angular insertion depth), and correlation between insertion depth and the speech perception outcomes. Results: A total of 215 relevant studies were assessed for eligibility. Twenty-three studies met the inclusion criteria and were analyzed further. Seven studies found no significant correlation between insertion depth and speech perception outcomes. Fifteen found either a significant positive correlation or a positive effect between insertion depth and speech perception. Only 1 study found a significant negative correlation between insertion depth and speech perception outcomes. Conclusion: Although most studies reported a positive effect of insertion depth on speech perception outcomes, one-third of the identified studies reported no correlation. Thus, the insertion depth must be considered as a contributing factor to speech perception rather than as a major decisive criterion. Registration: This review has been registered in PROSPERO, the international prospective register of systematic reviews (CRD42021257547), available at https://www.crd.york.ac.uk/PROSPERO/.

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One Click Is Not Enough: Anatomy-Based Fitting in Experienced Cochlear Implant Users

Cited by 20 publications

References 9 publications

Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth

Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth

Accuracy of Preoperative Cochlear Duct Length Estimation and Angular Insertion Depth Prediction

Effect of Cochlear Implant Electrode Insertion Depth on Speech Perception Outcomes: A Systematic Review

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