Open Access

A Two-Microphone Noise Reduction System for Cochlear Implant Users with Nearby Microphones—Part I: Signal Processing Algorithm Design and Development

  • Martin Kompis1Email author,
  • Matthias Bertram1, 2,
  • Jacques François3 and
  • Marco Pelizzone4
EURASIP Journal on Advances in Signal Processing20082008:647502

Received: 27 November 2007

Accepted: 20 March 2008

Published: 6 May 2008


Users of cochlear implant systems, that is, of auditory aids which stimulate the auditory nerve at the cochlea electrically, often complain about poor speech understanding in noisy environments. Despite the proven advantages of multimicrophone directional noise reduction systems for conventional hearing aids, only one major manufacturer has so far implemented such a system in a product, presumably because of the added power consumption and size. We present a physically small (intermicrophone distance 7 mm) and computationally inexpensive adaptive noise reduction system suitable for behind-the-ear cochlear implant speech processors. Supporting algorithms, which allow the adjustment of the opening angle and the maximum noise suppression, are proposed and evaluated. A portable real-time device for test in real acoustic environments is presented.

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Authors’ Affiliations

Department of ENT, Head and Neck Surgery Inselspital, University of Berne, Berne, Switzerland
Bernafon Inc., Berne, Berne, Switzerland
Laboratoire des Microprocesseurs, Ecole d'Ingénieurs de Genève, Geneva, Switzerland
Clinique O.R.L., Hôpital Universitaire de Genève, Geneva, Switzerland


© Martin Kompis et al. 2008

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.