title: Spatial hearing benefits demonstrated with presentation of acoustic temporal fine structure cues in bilateral cochlear implant listeners.
abstract: Most contemporary cochlear implant (CI) processing strategies discard acoustic temporal fine structure (TFS) information, and this may contribute to the observed deficits in bilateral CI listeners' ability to localize sounds when compared to normal hearing listeners. Additionally, for best speech envelope representation, most contemporary speech processing strategies use high-rate carriers (≥900 Hz) that exceed the limit for interaural pulse timing to provide useful binaural information. Many bilateral CI listeners are sensitive to interaural time differences (ITDs) in low-rate (<300 Hz) constant-amplitude pulse trains. This study explored the trade-off between superior speech temporal envelope representation with high-rate carriers and binaural pulse timing sensitivity with low-rate carriers. The effects of carrier pulse rate and pulse timing on ITD discrimination, ITD lateralization, and speech recognition in quiet were examined in eight bilateral CI listeners. Stimuli consisted of speech tokens processed at different electrical stimulation rates, and pulse timings that either preserved or did not preserve acoustic TFS cues. Results showed that CI listeners were able to use low-rate pulse timing cues derived from acoustic TFS when presented redundantly on multiple electrodes for ITD discrimination and lateralization of speech stimuli.
authors.affiliation: Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, Wisconsin 53705.
authors.forename: Tyler H
authors.initials: TH
authors.lastname: Churchill
authors.affiliation: Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, Wisconsin 53705.
authors.forename: Alan
authors.initials: A
authors.lastname: Kan
authors.affiliation: Department of Hearing and Speech Sciences, University of Maryland-College Park, College Park, Maryland 20742.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Goupell
authors.affiliation: Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, Wisconsin 53705.
authors.forename: Ruth Y
authors.initials: RY
authors.lastname: Litovsky
mesh_terms: D000161:Acoustic Stimulation; D000368:Aged; D001302:Audiometry, Speech; D019929:Cochlear Implantation / Q000295:instrumentation*; D003054:Cochlear Implants; D003463:Cues; D004558:Electric Stimulation; D007839:Functional Laterality; D006309:Hearing; D006801:Humans; D008875:Middle Aged; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*; D010898:Pitch Perception; D021641:Recognition, Psychology; D013017:Sound Localization; D013065:Speech Intelligibility; D013067:Speech Perception; D013997:Time Factors