Concurrent sound segregation in electric and acoustic hearing

Robert P. Carlyon*, Christopher J. Long, John M. Deeks, Colette M. McKay

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

We investigated potential cues to sound segregation by cochlear implant (CI) and normal-hearing (NH) listeners. In each presentation interval of experiment 1a, CI listeners heard a mixture of four pulse trains applied concurrently to separate electrodes, preceded by a "probe" applied to a single electrode. In one of these two intervals, which the subject had to identify, the probe electrode was the same as a "target" electrode in the mixture. The pulse train on the target electrode had a higher level than the others in the mixture. Additionally, it could be presented either with a 200-ms onset delay, at a lower rate, or with an asynchrony produced by delaying each pulse by about 5 ms re those on the nontarget electrodes. Neither the rate difference nor the asynchrony aided performance over and above the level difference alone, but the onset delay produced a modest improvement. Experiment 1b showed that two subjects could perform the task using the onset delay alone, with no level difference. Experiment 2 used a method similar to that of experiment 1, but investigated the onset cue using NH listeners. In one condition, the mixture consisted of harmonics 5 to 40 of a 100-Hz fundamental, with the onset of either harmonics 13 to 17 or 26 to 30 delayed re the rest. Performance was modest in this condition, but could be improved markedly by using stimuli containing a spectral gap between the target and nontarget harmonics. The results suggest that (a) CI users are unlikely to use temporal pitch differences between adjacent channels to separate concurrent sounds, and that (b) they can use onset differences between channels, but the usefulness of this cue will be compromised by the spread of excitation along the nerve-fiber array. This deleterious effect of spread-of-excitation can also impair the use of onset cues by NH listeners.

Original languageEnglish
Pages (from-to)119-133
Number of pages15
JournalJournal of the Association for Research in Otolaryngology
Volume8
Issue number1
DOIs
Publication statusPublished - 1 Mar 2007

Fingerprint

Acoustics
Hearing
Electrodes
Cues
Cochlear Implants
Nerve Fibers

Keywords

  • Cochlear implants
  • Grouping
  • Onset delays
  • Pitch

Cite this

Carlyon, Robert P. ; Long, Christopher J. ; Deeks, John M. ; McKay, Colette M. / Concurrent sound segregation in electric and acoustic hearing. In: Journal of the Association for Research in Otolaryngology. 2007 ; Vol. 8, No. 1. pp. 119-133.
@article{055cdeb64740413e9bee39c9ad0bdc9f,
title = "Concurrent sound segregation in electric and acoustic hearing",
abstract = "We investigated potential cues to sound segregation by cochlear implant (CI) and normal-hearing (NH) listeners. In each presentation interval of experiment 1a, CI listeners heard a mixture of four pulse trains applied concurrently to separate electrodes, preceded by a {"}probe{"} applied to a single electrode. In one of these two intervals, which the subject had to identify, the probe electrode was the same as a {"}target{"} electrode in the mixture. The pulse train on the target electrode had a higher level than the others in the mixture. Additionally, it could be presented either with a 200-ms onset delay, at a lower rate, or with an asynchrony produced by delaying each pulse by about 5 ms re those on the nontarget electrodes. Neither the rate difference nor the asynchrony aided performance over and above the level difference alone, but the onset delay produced a modest improvement. Experiment 1b showed that two subjects could perform the task using the onset delay alone, with no level difference. Experiment 2 used a method similar to that of experiment 1, but investigated the onset cue using NH listeners. In one condition, the mixture consisted of harmonics 5 to 40 of a 100-Hz fundamental, with the onset of either harmonics 13 to 17 or 26 to 30 delayed re the rest. Performance was modest in this condition, but could be improved markedly by using stimuli containing a spectral gap between the target and nontarget harmonics. The results suggest that (a) CI users are unlikely to use temporal pitch differences between adjacent channels to separate concurrent sounds, and that (b) they can use onset differences between channels, but the usefulness of this cue will be compromised by the spread of excitation along the nerve-fiber array. This deleterious effect of spread-of-excitation can also impair the use of onset cues by NH listeners.",
keywords = "Cochlear implants, Grouping, Onset delays, Pitch",
author = "Carlyon, {Robert P.} and Long, {Christopher J.} and Deeks, {John M.} and McKay, {Colette M.}",
year = "2007",
month = "3",
day = "1",
doi = "10.1007/s10162-006-0068-1",
language = "English",
volume = "8",
pages = "119--133",
journal = "Journal of the Association for Research in Otolaryngology",
issn = "1525-3961",
publisher = "Springer",
number = "1",

}

Concurrent sound segregation in electric and acoustic hearing. / Carlyon, Robert P.; Long, Christopher J.; Deeks, John M.; McKay, Colette M.

In: Journal of the Association for Research in Otolaryngology, Vol. 8, No. 1, 01.03.2007, p. 119-133.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Concurrent sound segregation in electric and acoustic hearing

AU - Carlyon, Robert P.

AU - Long, Christopher J.

AU - Deeks, John M.

AU - McKay, Colette M.

PY - 2007/3/1

Y1 - 2007/3/1

N2 - We investigated potential cues to sound segregation by cochlear implant (CI) and normal-hearing (NH) listeners. In each presentation interval of experiment 1a, CI listeners heard a mixture of four pulse trains applied concurrently to separate electrodes, preceded by a "probe" applied to a single electrode. In one of these two intervals, which the subject had to identify, the probe electrode was the same as a "target" electrode in the mixture. The pulse train on the target electrode had a higher level than the others in the mixture. Additionally, it could be presented either with a 200-ms onset delay, at a lower rate, or with an asynchrony produced by delaying each pulse by about 5 ms re those on the nontarget electrodes. Neither the rate difference nor the asynchrony aided performance over and above the level difference alone, but the onset delay produced a modest improvement. Experiment 1b showed that two subjects could perform the task using the onset delay alone, with no level difference. Experiment 2 used a method similar to that of experiment 1, but investigated the onset cue using NH listeners. In one condition, the mixture consisted of harmonics 5 to 40 of a 100-Hz fundamental, with the onset of either harmonics 13 to 17 or 26 to 30 delayed re the rest. Performance was modest in this condition, but could be improved markedly by using stimuli containing a spectral gap between the target and nontarget harmonics. The results suggest that (a) CI users are unlikely to use temporal pitch differences between adjacent channels to separate concurrent sounds, and that (b) they can use onset differences between channels, but the usefulness of this cue will be compromised by the spread of excitation along the nerve-fiber array. This deleterious effect of spread-of-excitation can also impair the use of onset cues by NH listeners.

AB - We investigated potential cues to sound segregation by cochlear implant (CI) and normal-hearing (NH) listeners. In each presentation interval of experiment 1a, CI listeners heard a mixture of four pulse trains applied concurrently to separate electrodes, preceded by a "probe" applied to a single electrode. In one of these two intervals, which the subject had to identify, the probe electrode was the same as a "target" electrode in the mixture. The pulse train on the target electrode had a higher level than the others in the mixture. Additionally, it could be presented either with a 200-ms onset delay, at a lower rate, or with an asynchrony produced by delaying each pulse by about 5 ms re those on the nontarget electrodes. Neither the rate difference nor the asynchrony aided performance over and above the level difference alone, but the onset delay produced a modest improvement. Experiment 1b showed that two subjects could perform the task using the onset delay alone, with no level difference. Experiment 2 used a method similar to that of experiment 1, but investigated the onset cue using NH listeners. In one condition, the mixture consisted of harmonics 5 to 40 of a 100-Hz fundamental, with the onset of either harmonics 13 to 17 or 26 to 30 delayed re the rest. Performance was modest in this condition, but could be improved markedly by using stimuli containing a spectral gap between the target and nontarget harmonics. The results suggest that (a) CI users are unlikely to use temporal pitch differences between adjacent channels to separate concurrent sounds, and that (b) they can use onset differences between channels, but the usefulness of this cue will be compromised by the spread of excitation along the nerve-fiber array. This deleterious effect of spread-of-excitation can also impair the use of onset cues by NH listeners.

KW - Cochlear implants

KW - Grouping

KW - Onset delays

KW - Pitch

UR - http://www.scopus.com/inward/record.url?scp=33846807690&partnerID=8YFLogxK

U2 - 10.1007/s10162-006-0068-1

DO - 10.1007/s10162-006-0068-1

M3 - Article

C2 - 17216383

AN - SCOPUS:33846807690

VL - 8

SP - 119

EP - 133

JO - Journal of the Association for Research in Otolaryngology

JF - Journal of the Association for Research in Otolaryngology

SN - 1525-3961

IS - 1

ER -