TY - JOUR
T1 - Encoding pitch contours using current steering
AU - Luo, Xin
AU - Landsberger, David M.
AU - Padilla, Monica
AU - Srinivasan, Arthi G.
N1 - Funding Information:
We are grateful to all subjects for their participation in the experiments. We would also like to thank the Associate Editor and three anonymous reviewers for their constructive comments on an earlier version of the manuscript. Research was supported in part by NIH (Grant Nos. R03-DC-008192 to X.L., R03-DC-010064 to D.M.L., and R01-DC-001526 to Robert V. Shannon).
PY - 2010/9
Y1 - 2010/9
N2 - This study investigated cochlear implant (CI) users' ability to perceive pitch cues from time-varying virtual channels (VCs) to identify pitch contours. Seven CI users were tested on apical, medial, and basal electrode pairs with stimulus durations from 100 to 1000 ms. In one stimulus set, 9 pitch contours were created by steering current between the component electrodes and the VC halfway between the electrodes. Another stimulus set only contained 3 pitch contours (flat, falling, and rising). VC discrimination was also tested on the same electrodes. The total current level of dual-electrode stimuli was linearly interpolated between those of single-electrode stimuli to minimize loudness changes. The results showed that pitch contour identification (PCI) scores were similar across electrode locations, and significantly improved at longer durations. For durations longer than 300 ms, 2 subjects had nearly perfect 9-contour identification, and 5 subjects perfectly identified the 3 basic contours. Both PCI and VC discrimination varied greatly across subjects. Cumulative d′ values for VC discrimination were significantly correlated with 100-, 200-, and 500-ms PCI scores. These results verify the feasibility of encoding pitch contours using current steering, and suggest that identification of such pitch contours strongly relies on CI users' sensitivity to VCs.
AB - This study investigated cochlear implant (CI) users' ability to perceive pitch cues from time-varying virtual channels (VCs) to identify pitch contours. Seven CI users were tested on apical, medial, and basal electrode pairs with stimulus durations from 100 to 1000 ms. In one stimulus set, 9 pitch contours were created by steering current between the component electrodes and the VC halfway between the electrodes. Another stimulus set only contained 3 pitch contours (flat, falling, and rising). VC discrimination was also tested on the same electrodes. The total current level of dual-electrode stimuli was linearly interpolated between those of single-electrode stimuli to minimize loudness changes. The results showed that pitch contour identification (PCI) scores were similar across electrode locations, and significantly improved at longer durations. For durations longer than 300 ms, 2 subjects had nearly perfect 9-contour identification, and 5 subjects perfectly identified the 3 basic contours. Both PCI and VC discrimination varied greatly across subjects. Cumulative d′ values for VC discrimination were significantly correlated with 100-, 200-, and 500-ms PCI scores. These results verify the feasibility of encoding pitch contours using current steering, and suggest that identification of such pitch contours strongly relies on CI users' sensitivity to VCs.
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U2 - 10.1121/1.3474237
DO - 10.1121/1.3474237
M3 - Article
C2 - 20815457
AN - SCOPUS:77956396912
SN - 0001-4966
VL - 128
SP - 1215
EP - 1223
JO - Journal of the Acoustical Society of America
JF - Journal of the Acoustical Society of America
IS - 3
ER -