gms | German Medical Science

79th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

30.04. - 04.05.2008, Bonn

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Auditory Midbrain Implant: effects of multi-site stimulation along the isofrequency laminae of the inferior colliculus central nucleus on auditory cortical activity

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  • corresponding author Roger Calixto - Medizinische Hochschule Hannover, Hannover, Germany
  • Hubert H. Lim - Medizinische Hochschule Hannover, Hannover
  • Anke Neuheiser - Medizinische Hochschule Hannover, Hannover
  • Guenter Reuter - Medizinische Hochschule Hannover, Hannover
  • Thomas Lenarz - Medizinische Hochschule Hannover, Hannover
  • Minoo Lenarz - Medizinische Hochschule Hannover, Hannover

Deutsche Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie. 79. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie. Bonn, 30.04.-04.05.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. Doc08hnod386

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/hnod2008/08hnod386.shtml

Published: April 22, 2008

© 2008 Calixto et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Introduction: The auditory midbrain implant (AMI), designed for electrical stimulation of the inferior colliculus central nucleus (ICC) for hearing restoration, is now in clinical trials. All four implanted patients obtain hearing improvements on a daily basis with our single shank array and simple stimulation strategies. Since the ICC is a complex 3-D structure, we investigated in an animal model if further improvements may be achieved by stimulating across multiple regions throughout the ICC.

Methods: Two single shank multi-site arrays were inserted along the tonotopic gradient of the ICC in ketamine-anesthetized guinea pigs. We then recorded cortical responses to electrical stimulation (with single pulses, cathodic-leading, biphasic, 205 µs/phase) of two ICC sites within the same frequency lamina and with varying inter-site delays.

Results: Superposition of activity for two stimulated sites depends strongly on the inter-site delay and can exhibit nonlinear activation properties. Furthermore, there exists a crucial time window in which one stimulated site can elicit the maximum effect on a proceeding stimulated site that depends on stimulation location.

Conclusion: These findings have important implications as to how multiple regions within the ICC can be stimulated to elicit nonlinear and enhanced neural activation within higher auditory centers. Potential behavioral correlates of these electrophysiological findings will be discussed in terms of future AMI stimulation strategies.

Unterstützt durch: Funding provided by Cochlear Ltd. and SFB 599