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dc.contributor.authorMonaghan, Jessica JM
dc.contributor.authorCarlyon, Robert P
dc.contributor.authorDeeks, John
dc.date.accessioned2022-03-31T18:00:26Z
dc.date.available2022-03-31T18:00:26Z
dc.date.issued2022-04
dc.date.submitted2021-02-23
dc.identifier.issn1525-3961
dc.identifier.others10162-022-00834-6
dc.identifier.other834
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/335593
dc.descriptionFunder: Macquarie University
dc.description.abstractCochlear implants (CIs) convey the amplitude envelope of speech by modulating high-rate pulse trains. However, not all of the envelope may be necessary to perceive amplitude modulations (AMs); the effective envelope depth may be limited by forward and backward masking from the envelope peaks. Three experiments used modulated pulse trains to measure which portions of the envelope can be effectively processed by CI users as a function of AM frequency. Experiment 1 used a three-interval forced-choice task to test the ability of CI users to discriminate less-modulated pulse trains from a fully modulated standard, without controlling for loudness. The stimuli in experiment 2 were identical, but a two-interval task was used in which participants were required to choose the less-modulated interval, ignoring loudness. Catch trials, in which judgements based on level or modulation depth would give opposing answers, were included. Experiment 3 employed novel stimuli whose modulation envelope could be modified below a variable point in the dynamic range, without changing the loudness of the stimulus. Overall, results showed that substantial portions of the envelope are not accurately encoded by CI users. In experiment 1, where loudness cues were available, participants on average were insensitive to changes in the bottom 30% of their dynamic range. In experiment 2, where loudness was controlled, participants appeared insensitive to changes in the bottom 50% of the dynamic range. In experiment 3, participants were insensitive to changes in the bottom 80% of the dynamic range. We discuss potential reasons for this insensitivity and implications for CI speech-processing strategies.
dc.languageen
dc.publisherSpringer Science and Business Media LLC
dc.subjectResearch Article
dc.subjectCochlear implant (CI)
dc.subjectModulation depth discrimination
dc.subjectAmplitude modulation sensitivity
dc.subjectMasking
dc.subjectTemporal processing
dc.subjectTemporal window
dc.subjectEnvelope
dc.titleModulation Depth Discrimination by Cochlear Implant Users.
dc.typeArticle
dc.date.updated2022-03-31T18:00:26Z
prism.endingPage299
prism.issueIdentifier2
prism.publicationNameJ Assoc Res Otolaryngol
prism.startingPage285
prism.volume23
dc.identifier.doi10.17863/CAM.83024
dcterms.dateAccepted2021-12-30
rioxxterms.versionofrecord10.1007/s10162-022-00834-6
rioxxterms.versionVoR
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/
dc.contributor.orcidMonaghan, Jessica JM [0000-0003-1416-4164]
dc.identifier.eissn1438-7573
pubs.funder-project-idMedical Research Council (MC_UU_00005/3)
cam.issuedOnline2022-01-26


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