Objective:

This study explores the adaptation of localization mechanisms to warping of spectral localization features, as required for CI listeners to map those features to their reduced electric stimulation range.

Methods and Results:

The effect of warping the stimulation range from 2.8 to 16 kHz to the range from 2.8 to 8.5 kHz was studied in normal-hearing listeners. Fifteen subjects participated in a long-time localization-training study, involving two-hour daily audio-visual training over a period of three weeks. The Test Group listened to frequency-warped stimuli, the Control Group to low-pass filtered stimuli (8.5 kHz). The Control Group showed an initial increase of localization error and essentially reached the baseline performance at the end of the training period. The Test Group showed a strong initial increase of localization error, followed by a steady improvement of performance, even though not reaching the baseline performance at the end of the training period. These results are promising with respect to the idea to present high-frequency spectral localization cues to the stimulation range available with CIs

Funding:

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

Publications:

  • Walder, T. (2010) Schallquellenlokalisation mittels Frequenzbereich-Kompression der Außenohrübertragungsfunktionen (englisch: Sound source localization with frequency-range compressed head-related transfer functions), Master thesis, Technical University of Graz & Kunstuniversität Graz.
  • Majdak, P., Walder, T., and Laback, B. (2011). Learning to Localize Band-Limited Sounds in Vertical Planes, presented at: 34st MidWinter Meeting of the Association for Research in Otolaryngology (ARO). Baltimore, Maryland.