Objective:

This project studies the effects of the upper-frequency boundary and of spectral warping on speech intelligibility among Cochlear Implant (CI) listeners, using a 12-channel implant, and normal hearing (NH) listeners.  This is important to determine how many basal channels are "free" for encoding spectral localization cues.

Results:

The results show that eight frequency channels and spectral content up to about 3 kHz are sufficient to transmit speech under unwarped conditions. If frequency warping was applied, the changes had to be limited ± 2 frequency channels to preserve good speech understanding. This outcome shows the range of allowed modifications for presenting spectral localization cues to CI listeners. About four channels were found to be "free" for encoding spectral localization cues

Application:

see the description of the CI-HRTF project

Funding:

FWF (Austrian Science Fund): Project #P18401-B15

Publications:

  • Goupell, M., Laback, B., Majdak, P., and Baumgartner, W. D. (2007). Effects of upper-frequency boundary and spectral warping on speech intelligibility in electrical stimulation, J. Acoust. Soc. Am. 123, 2295-2309.
  • Goupell, M. J., Laback, B., Majdak, P., and Baumgartner, W-D. (2007). Effect of frequency-place mapping on speech intelligibility: implications for a cochlear implant localization strategy, presented at Conference on Implantable Auditory Prostheses (CIAP), Lake Tahoe.
  • Goupell, M. J., Laback, B., Majdak, P., and Baumgartner, W-D. (2007). Effect of different frequency mappings on speech intelligibility for CI listeners, proceedings of DAGA 2007, Stuttgart.