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  • Research Article
  • Open Access

A Psychoacoustic "NofM"-Type Speech Coding Strategy for Cochlear Implants

  • 1Email author,
  • 2,
  • 2 and
  • 1
EURASIP Journal on Advances in Signal Processing20052005:101672

  • Received: 1 June 2004
  • Published:


We describe a new signal processing technique for cochlear implants using a psychoacoustic-masking model. The technique is based on the principle of a so-called "NofM" strategy. These strategies stimulate fewer channels ( ) per cycle than active electrodes (NofM; ). In "NofM" strategies such as ACE or SPEAK, only the channels with higher amplitudes are stimulated. The new strategy is based on the ACE strategy but uses a psychoacoustic-masking model in order to determine the essential components of any given audio signal. This new strategy was tested on device users in an acute study, with either 4 or 8 channels stimulated per cycle. For the first condition (4 channels), the mean improvement over the ACE strategy was . For the second condition (8 channels), no significant difference was found between the two strategies.

Keywords and phrases:

  • cochlear implant
  • NofM
  • ACE
  • speech coding
  • psychoacoustic model
  • masking

Authors’ Affiliations

Laboratorium für Informationstechnologie, Universität Hannover, Schneiderberg 32, Hannover, 30167, Germany
Department of Otolaryngology, Medical University Hanover, Carl-Neuberg-Strasse 1, Hannover, 30625, Germany