The auditory nerve implant-concept and device description of a novel electrical auditory prosthesis

Thomas Lenarz¹, Florian Solzbacher^{2

3

4

5}, Loren Rieth^{6

7}, Moritz Leber⁵, Meredith E Adams^{8

9}, Rolf Salcher¹, David J Warren^{2

3}, Andrew J Oxenham^{8

10}, Karl-Heinz Dyballa¹, Amir Samii¹¹, Robert K Franklin⁵, Waldo Nogueira^{1

12}, Inderbir Sondh⁸, Abigail P Heiller¹³, Joseph D Crew⁵, Keno Huebner¹⁴, Stefan Strahl¹⁴, Holly A Holman³, Luke A Johnson¹⁵, Geoffrey M Ghose¹⁶, W Mitchel Thomas¹⁷, Cornelia Batsoulis¹⁸, Ingeborg Hochmair¹⁴, Lei Feng¹⁹, Hubert H Lim^{8

13

20}

Affiliations

¹ Department of Otolaryngology, Hannover Medical School, Hannover, Germany.
² Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, USA.
³ Department of Biomedical Engineering, University of Utah, Salt Lake City, USA.
⁴ Department of Materials Science and Engineering, University of Utah, Salt Lake City, USA.
⁵ Blackrock Neurotech, Salt Lake City, USA.
⁶ Department of Mechanical, Materials and Aerospace Engineering, West Virginia University, Morgantown, USA.
⁷ Department of Chemical and Biomedical Engineering, West Virginia University, Morgantown, USA.
⁸ Department of Otolaryngology-Head and Neck Surgery, University of Minnesota, Minneapolis, USA.
⁹ Now with Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, USA.
¹⁰ Department of Psychology, University of Minnesota, Minneapolis, USA.
¹¹ Department of Neurosurgery, International Neuroscience Institute, Hannover, Germany.
¹² Cluster of Excellence "Hearing4all", Hannover, Germany.
¹³ Department of Biomedical Engineering, University of Minnesota, Minneapolis, USA.
¹⁴ MED-EL Medical Electronics, Innsbruck, Austria.
¹⁵ Department of Neurology, University of Minnesota, Minneapolis, USA.
¹⁶ Department of Neuroscience, University of Minnesota, Minneapolis, USA.
¹⁷ Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins Medicine, Baltimore, USA.
¹⁸ MED-EL Medical Electronics, MED-EL Research Center, Hannover, Germany.
¹⁹ Department of Otolaryngology-Head and Neck Surgery, University of Minnesota, Minneapolis, USA. fengl@umn.edu.
²⁰ Institute for Translational Neuroscience, University of Minnesota, Minneapolis, USA.

PMID: 41131644
PMCID: PMC12551331
DOI: 10.1186/s42234-025-00188-3

Review

The auditory nerve implant-concept and device description of a novel electrical auditory prosthesis

Thomas Lenarz et al. Bioelectron Med. 2025.

. 2025 Oct 24;11(1):26.

doi: 10.1186/s42234-025-00188-3.

Authors

Affiliations

¹ Department of Otolaryngology, Hannover Medical School, Hannover, Germany.
² Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, USA.
³ Department of Biomedical Engineering, University of Utah, Salt Lake City, USA.
⁴ Department of Materials Science and Engineering, University of Utah, Salt Lake City, USA.
⁵ Blackrock Neurotech, Salt Lake City, USA.
⁶ Department of Mechanical, Materials and Aerospace Engineering, West Virginia University, Morgantown, USA.
⁷ Department of Chemical and Biomedical Engineering, West Virginia University, Morgantown, USA.
⁸ Department of Otolaryngology-Head and Neck Surgery, University of Minnesota, Minneapolis, USA.
⁹ Now with Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, USA.
¹⁰ Department of Psychology, University of Minnesota, Minneapolis, USA.
¹¹ Department of Neurosurgery, International Neuroscience Institute, Hannover, Germany.
¹² Cluster of Excellence "Hearing4all", Hannover, Germany.
¹³ Department of Biomedical Engineering, University of Minnesota, Minneapolis, USA.
¹⁴ MED-EL Medical Electronics, Innsbruck, Austria.
¹⁵ Department of Neurology, University of Minnesota, Minneapolis, USA.
¹⁶ Department of Neuroscience, University of Minnesota, Minneapolis, USA.
¹⁷ Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins Medicine, Baltimore, USA.
¹⁸ MED-EL Medical Electronics, MED-EL Research Center, Hannover, Germany.
¹⁹ Department of Otolaryngology-Head and Neck Surgery, University of Minnesota, Minneapolis, USA. fengl@umn.edu.
²⁰ Institute for Translational Neuroscience, University of Minnesota, Minneapolis, USA.

PMID: 41131644
PMCID: PMC12551331
DOI: 10.1186/s42234-025-00188-3

Abstract

The cochlear implant (CI) is considered one of the most successful neural prostheses, enabling deaf individuals to achieve intelligible speech perception. However, CI performance remains limited in noise and with complex acoustic scenes, including music and multi-talker speech. One major issue for CIs is the poor electrode-neural interface where electrodes are positioned within the bony cochlea and distant from the auditory nerve fibers. Due to recent advances with microelectrode technologies designed for peripheral nerves, there has been rekindled interest in the auditory nerve implant (ANI), in which a novel prosthesis with a microelectrode array has been developed for direct stimulation of the auditory nerve. Animal studies demonstrate that the ANI achieves substantially lower thresholds and more selective neural activation compared to CI stimulation, which could lead to greater hearing performance. To successfully translate the ANI to patients, the ANI device components need to be further designed for safe and reliable implantation in humans through development of alternative surgical techniques, and validated in chronic animal studies. New stimulation strategies also need to be developed, especially with the potential to insert tens to hundreds of microelectrodes across the spiraling tonotopy of the auditory nerve to activate more spatially and temporally distinct nerve fiber patterns than is possible with the CI. Once in humans, extensive perceptual experiments can be performed with the ANI to characterize thresholds, loudness growth functions, pitch patterns, temporal coding properties, and spectral selectivity, as well as evaluating novel stimulation strategies that will guide the development of the next generation ANI system.

Keywords: Auditory brainstem implant; Auditory nerve; Cochlear implant; Electrode-neural interface; Hearing loss; Microelectrode array; Neural prosthesis; Neuromodulation.

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

**Fig. 1**
Concept of the auditory nerve implant (ANI) system consisting of an audio processor and cochlear implant simulator (MED-EL, Innsbruck, Austria) integrated with the ANI array (Blackrock Neurotech, Salt Lake City, Utah), which is placed directly into the auditory nerve medial to its exit from the cochlea. Image courtesy of Blackrock Neurotech and MED-EL. This schematic portrays the concept of the ANI system in which individual components are not drawn to scale or do not represent the final design that will be implanted in humans, and the placement along the nerve is expected to be closer to the cochlea within the IAC

**Fig. 2**
The components of the ANI system. (A) Backside of the integrated device, showing the silicone wing (A.1) for surgical handling, a MED-EL Synchrony 2 cochlear stimulator (A.2 and A.3), and the helical lead (A.4) for enhanced mechanical stability. (B) Close-up of the ANI array, highlighting its 3 × 5 microelectrode configuration (B.1), platinum handling fin for surgical manipulation (B.2), bendable plastic section of the wire bundle (B.3), and the beginning of the helical lead (B.4)

See this image and copyright information in PMC

References

1. Alexiades G, Dhanasingh A, Jolly C. Method to estimate the complete and two-turn cochlear duct length. Otol Neurotol. 2015;36(5):904–7. - PubMed
1. Aoyagi Y, Stein RB, Branner A, Pearson KG, Normann RA. Capabilities of a penetrating microelectrode array for recording single units in dorsal root ganglia of the cat. J Neurosci Methods. 2003;128(1–2):9–20. - PubMed
1. Aravamudhan R, Lotto AJ. Phonetic context effects in adult listeners with cochlear implants. J Acoust Soc Am. 2005;118(3_Supplement):1962–3.
1. Badi AN, Hillman T, Shelton C, Normann RA. A technique for implantation of a 3-dimensional penetrating electrode array in the modiolar nerve of cats and humans. Arch Otolaryngol Head Neck Surg. 2002;128(9):1019–25. - PubMed
1. Badi AN, Kertesz TR, Gurgel RK, Shelton C, Normann RA. Development of a novel eighth-nerve intraneural auditory neuroprosthesis. Laryngoscope. 2003;113(5):833–42. - PubMed

Save citation to file

Email citation

Add to Collections

Add to My Bibliography

Your saved search

Create a file for external citation management software

Your RSS Feed

The auditory nerve implant-concept and device description of a novel electrical auditory prosthesis

Affiliations

The auditory nerve implant-concept and device description of a novel electrical auditory prosthesis

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

References

Publication types

Grants and funding

LinkOut - more resources

Full Text Sources