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

Article

Send article

On the variability of intracochlear measured threshold profiles of electrically evoked compound action potentials of cochlear implant patients

Meeting Abstract

Search Medline for

  • corresponding author Lutz Gärtner - Medical University of Hannover, Hannover, Germany
  • Andreas Büchner - Medical University of Hannover, Hannover, Germany
  • Rolf-Dieter Battmer - Medical University of Hannover, Hannover, Germany
  • Thomas Lenarz - Medical University of Hannover, Hannover, Germany

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. 79th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. Bonn, 30.04.-04.05.2008. Düsseldorf, Köln: German Medical Science; 2008. Doc08hno12

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/hno2008/08hno12.shtml

Published: July 8, 2008

© 2008 Gärtner 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

Text

Introduction: The thresholds of electrically evoked compound action potentials (ECAP) are increasingly used to program speech processors of cochlear implant patients. The AutoNRTTM of Cochlear provides a quite reliable system to automatically derive the ECAP-thresholds. However, occasionally occurring variations in this profile are not reflected in the profile of the C(“comfort”)-levels [1].

Methods: At the MHH all patients supplied with a Nucleus RE24-CA „Freedom“-implant are routinely subject to AutoNRT measurements, which are evaluated across the entire electrode array (22 electrodes). In this work the variability of the ECAP-profiles is further researched. It is analysed, if the variations can be explained either by so called T-tails, either by measurement uncertainties, or if they remain stable over time.

Results: Two classes of temporal variations can be identified: A) A displacement of the entire profile, B) An alteration of the thresholds of single electrodes. In one case, both the average ECAP-threshold and the C-level increases up to more then 30CL within 3 months. In another case, a particular ECAP-threshold alters about 90CL, whereas the corresponding C-level only changes about 20CL.

Conclusion and outlook: Although T-tail effects could be detected, they cannot sufficiently explain the observed variability of the ECAP-profile.

Outline

References

1.
Gärtner L, Büchner A, Battmer RD, Lenarz T. Anpassung von Cochlea-Implantat-Patienten unter Anwendung eines automatischen Systems zur Aufzeichnung und Auswertung von elektrisch evozierten Summenaktionspotentialen. GMS Curr Posters Otorhinolaryngol Head Neck Surg. 2007;3:Doc71 (20070425). Verfügbar unter: http://www.egms.de/en/journals/cpo/2007-3/cpo000336.shtml External link