Abstract
Cochlear implants use electrical stimulation of the auditory nerve to restore the sensation of hearing to deaf people. Unfortunately, the stimulation current spreads extensively within the cochlea, resulting in 'blurring' of the signal, and hearing that is far from normal. Current spread can be indirectly measured using the implant electrodes for both stimulating and sensing, but this provides incomplete information near the stimulating electrode due to electrode-electrolyte interface effects. Here, we present a 3D-printed 'unwrapped' physical cochlea model with integrated sensing wires. We integrate resistors into the walls of the model to simulate current spread through the cochlear bony wall, and 'tune' these resistances by calibration with an in-vivo electrical measurement from a cochlear implant patient. We then use this model to compare electrical current spread under different stimulation modes including monopolar, bipolar and tripolar configurations. Importantly, a trade-off is observed between stimulation amplitude and current focusing among different stimulation modes. By combining different stimulation modes and changing intracochlear current sinking configurations in the model, we explore this trade-off between stimulation amplitude and focusing further. These results will inform clinical strategies for use in delivering speech signals to cochlear implant patients.
| Original language | English |
|---|---|
| Article number | 9354566 |
| Pages (from-to) | 2281-2288 |
| Number of pages | 8 |
| Journal | IEEE Transactions on Biomedical Engineering |
| Volume | 68 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - Jul 2021 |
Bibliographical note
Funding Information:February 15,2021;dateof currentversionJune 18,2021.ThisworkDecember23,2020;acceptedJanuary 27,2021.Dateof publication Cdevicesfortherehabilitationofsevere-to-profoundhear- wassupportedinpartbytheEvelynTrust,theWellcomeTrustJunior ing loss [1], [2]. However, the restored hearing function is far Interdisciplinary Fellowship under Grant 204845/Z/16/Z, the Cambridge from normal. Most CI users’ speech comprehension breaks Hearing Trust and in part by the Advanced Bionics Corporation for down in challenging listening conditions with background noise, andShreyaSinghalcontributedequallytothiswork.) (Correspondingprovidingcochlearimplantsandsoftwareonthisresearch.(ChenJiang and music is poorly appreciated [3], [4]. Additionally, a small, authors: Chen Jiang; George G. Malliaras; Manohar L. Bance.) but significant proportion of patients perform poorly for speech Chen Jiang was with the Cambridge Hearing Group, Depart- comprehension even in quiet environments [5]. Despite CIs BiomedicalCampus, UniversityofCambridge, CB20AH Cambridge,ment of ClinicalNeurosciences,CliffordAllbuttBuilding,Cambridge having up to 26 intracochlear electrodes that can be used for U.K., and Chen Jiang is now with the Department of Electronic the stimulation [6], traditionally only between 4-8 independent Engineering, Tsinghua University, Beijing 100084, China (e-mail: channels of information have been reported [7], [8]. These Iwan V. Roberts, Simone R. de Rijk, and Tim Brochier are withchenjiang@tsinghua.edu.cn). issues can be largely attributed to current spread, that results the Cambridge Hearing Group, Department of Clinical Neurosciences, in “blurring” of the input signal at the neuronal level [9]. The CliffordAllbuttBuilding,Cambridge BiomedicalCampus,Universityof importance of current is seen not just in cochlear implants but Shreya Singhalis with the Electrical EngineeringCambridge. also in other neural prostheses that require independent spatial ment of Engineering, University of Cambridge. channels for optimal performance, rather than just time domain Thomas Landry is with the School of Biomedical parameters such as stimulation rate [10], [11].
Publisher Copyright:
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ASJC Scopus Subject Areas
- Biomedical Engineering
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't