Abstract
This study examined the effect of noise on the identification of four synthetic speech continua (/ra/-/la/, /wa/-/ja/, /i/-/u/, and say-stay) by adults with cochlea implants (CIs) and adults with normal-hearing (NH) sensitivity in quiet and noise. Significant group-by-SNR interactions were found for endpoint identification accuracy for all continua except /i/-/u/. The CI listeners showed the least NH-like identification functions for the /ra/-/la/ and /wa/-/ja/ continua. In a second experiment, NH adults identified four- and eight-band cochlear implant stimulations of the four continua, to examine whether group differences in frequency selectivity could account for the group differences in the first experiment. Number of bands and SNR interacted significantly for /ra/-/la/, /wa/-/ja/, and say-stay endpoint identification; strongest effects were found for the /ra/la/ and say-stay continua. Results suggest that the speech features that are most vulnerable to misperception in noise by listeners with CIs are those whose acoustic cues are rapidly changing spectral patterns, like the formant transitions in the /wa/-/ja/ and /ra/la/ continua. However, the group differences in the first experiment cannot be wholly attributable to frequency selectivity differences, as the number of bands in the second experiment affected performance differently than suggested by group differences in the first experiment.
Original language | English (US) |
---|---|
Pages (from-to) | 2607-2617 |
Number of pages | 11 |
Journal | Journal of the Acoustical Society of America |
Volume | 118 |
Issue number | 4 |
DOIs | |
State | Published - Oct 2005 |
Bibliographical note
Funding Information:This research was supported by NIH Grant No. P01 DC00110 to David A. Nelson, by the Lions 3M Hearing Foundation, and by the Bryn Bryngelson fund in the Department of Speech-Language-Hearing Sciences. We generously thank Ankita Patel, Patrick J. Van Groll, and Heather Kreft for assistance in participant recruitment, data collection, and data analysis for experiment 1. We thank Edward Carney for assistance in writing software to conduct a pilot version of experiment 1, and for conducting probit analyses. We generously acknowledge Jill Muecke for creating stimuli and testing subjects for experiment 2. This work was presented at the Fall 2003 and Spring 2004 meetings of the Acoustical Society of America. We thank those audiences for their helpful comments. We also thank Su-Hyun Jin and Gail Donaldson for their valuable comments on this work as it was in progress. 1