Development and Validation of a High-Fidelity Finite-Element Model of Monopolar Stimulation in the Implanted Guinea Pig Cochlea

Wong, Paul; George, Sheela; Tran, Phillip; Sue, Andrian; Carter, Paul; Li, Qing

doi:10.1109/tbme.2015.2480601

Cited by 24 publications

(28 citation statements)

References 27 publications

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“…Existing models deal with this issue by assuming that the end of the auditory nerve is grounded, that the ground is infinitely far away, or that the boundary box surfaces are grounded. However, none of these perfectly match the in vivo situation (Wong et al, 2016). We simulated monopolar stimulation creating one active electrode within the electrode array in the cochlea and defining the ground as a sphere with a radius of size 50 mm that housed the whole cochlea.…”

Section: Methodsmentioning

confidence: 93%

Validation of a Cochlear Implant Patient-Specific Model of the Voltage Distribution in a Clinical Setting

Nogueira

Schurzig

Büchner

et al. 2016

Front. Bioeng. Biotechnol.

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Cochlear Implants (CIs) are medical implantable devices that can restore the sense of hearing in people with profound hearing loss. Clinical trials assessing speech intelligibility in CI users have found large intersubject variability. One possibility to explain the variability is the individual differences in the interface created between electrodes of the CI and the auditory nerve. In order to understand the variability, models of the voltage distribution of the electrically stimulated cochlea may be useful. With this purpose in mind, we developed a parametric model that can be adapted to each CI user based on landmarks from individual cone beam computed tomography (CBCT) scans of the cochlea before and after implantation. The conductivity values of each cochlea compartment as well as the weighting factors of different grounding modes have also been parameterized. Simulations were performed modeling the cochlea and electrode positions of 12 CI users. Three models were compared with different levels of detail: a homogeneous model (HM), a non-patient-specific model (NPSM), and a patient-specific model (PSM). The model simulations were compared with voltage distribution measurements obtained from the backward telemetry of the 12 CI users. Results show that the PSM produces the lowest error when predicting individual voltage distributions. Given a patient-specific geometry and electrode positions, we show an example on how to optimize the parameters of the model and how to couple it to an auditory nerve model. The model here presented may help to understand speech performance variability and support the development of new sound coding strategies for CIs.

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Section: Methodsmentioning

confidence: 93%

Validation of a Cochlear Implant Patient-Specific Model of the Voltage Distribution in a Clinical Setting

Nogueira

Schurzig

Büchner

et al. 2016

Front. Bioeng. Biotechnol.

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“…The reference electrode was located on the scalp, according to its prescribed placement on implant housing. The simulation of this reference electrode has proved to have an important role on the current paths predicted by the electrical conduction model and consequently, on the neural excitation patterns [15,36]. All elements were merged and transformed into a single volumetric mesh (Figure 1.F), leading to a mesh free of intersections of approximately 2•10 6 tetrahedral elements.…”

Section: Finite Element Modelmentioning

confidence: 99%

Towards a Complete In Silico Assessment of the Outcome of Cochlear Implantation Surgery

et al. 2017

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Cochlear implantation (CI) surgery is a very successful technique, performed on more than 300,000 people worldwide. However, since the challenge resides in obtaining an accurate surgical planning, computational models are considered to provide such accurate tools. They allow us to plan and simulate beforehand surgical procedures in order to maximally optimize surgery outcomes, and consequently provide valuable information to guide pre-operative decisions. The aim of this work is to develop and validate computational tools to completely assess the patient-specific functional outcome of the CI surgery. A complete automatic framework was developed to create and assess computationally CI models, focusing on the neural response of the auditory nerve fibers (ANF) induced by the electrical stimulation of the implant. The framework was applied to evaluate the effects of ANF degeneration and electrode intra-cochlear position on nerve activation. Results indicate that the intra-cochlear positioning of the electrode has a strong effect on the global performance of the CI. Lateral insertion provides better neural responses in case of peripheral process degeneration, and it is recommended, together with optimized intensity levels, in order to preserve the internal structures. Overall, the developed automatic framework provides an insight into the global performance of the implant in a patient-specific way. This enables to further optimize the functional performance and helps to select the best CI configuration and treatment strategy for a given patient.

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“…Three-dimensional (3D) approaches model the conductivity in the different sections and tissues of the cochlea, the modiolus, and the surrounding area and have thus predictive power to be used in the design of implant electrodes, as described in the reviews by Hanekom and Hanekom (2016) and by Kalkman et al (2016) in this issue. First, a volume conduction description of the cochlea is obtained from images of the cochlea, for example, from histologic sectioning (Wong et al 2016). These high-resolution images form the basis for the 3D model and they can be aligned to patient-individual images obtained from micro-computed tomography (µCT).…”

Section: Recent Developmentsmentioning

confidence: 99%

The history and future of neural modeling for cochlear implants

Seeber

Bruce

2016

Network: Computation in Neural Systems

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This special issue of Network: Computation in Neural Systems on the topic of "Computational models of the electrically stimulated auditory system" incorporates review articles spanning a wide range of approaches to modeling cochlear implant stimulation of the auditory system. The purpose of this overview paper is to provide a historical context for the different modeling endeavors and to point toward how computational modeling could play a key role in the understanding, evaluation, and improvement of cochlear implants in the future.

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Development and Validation of a High-Fidelity Finite-Element Model of Monopolar Stimulation in the Implanted Guinea Pig Cochlea

Abstract: These findings address a long-standing knowledge gap about appropriate boundary conditions, and will help to promote wider acceptance of insights from computational models of the cochlea.

Cited by 24 publications

References 27 publications

Validation of a Cochlear Implant Patient-Specific Model of the Voltage Distribution in a Clinical Setting

Validation of a Cochlear Implant Patient-Specific Model of the Voltage Distribution in a Clinical Setting

Towards a Complete In Silico Assessment of the Outcome of Cochlear Implantation Surgery

The history and future of neural modeling for cochlear implants

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