The purpose of this study was to improve the speech processing strategy for cochlear implants (CIs) based on a nonlinear time-varying filter model of a biological cochlea. The level-dependent frequency response characteristic of the basilar membrane is known to produce robust formant representation and speech perception in noise. A dual resonance nonlinear (DRNL) model was adopted because it is simpler than other adaptive nonlinear models of the basilar membrane and can be readily incorporated into the CI speech processor. Spectral analysis showed that formant information is more saliently represented at the output of the proposed CI speech processor compared to the conventional strategy in noisy conditions. Acoustic simulation and hearing experiments showed that the DRNL-based nonlinear strategy improves speech performance in a speech-spectrum-shaped noise.
Bibliographical noteFunding Information:
Manuscript received December 24, 2007; revised June 11, 2008 and September 22, 2008. First published October 31, 2008; current version published April 15, 2009. This work was supported by the Korea Science and Engineering Foundation through the Nano Bioelectronics and Systems Research Center (NBS-ERC), Seoul National University under Grant R11-2000-075-01005-0. Asterisk indicates corresponding author.
All Science Journal Classification (ASJC) codes
- Biomedical Engineering