title: Overlapping frequency coverage and simulated spatial cue effects on bimodal (electrical and acoustical) sentence recognition in noise.
abstract: Sentence recognition in 20-talker babble was measured in eight Nucleus cochlear implant (CI) users with contralateral residual acoustic hearing. Speech reception thresholds (SRTs) were measured both in standard configurations, with some frequency regions presented both acoustically and electrically, and in configurations with no spectral overlap. In both cases a continuous interleaved sampling strategy was used. Mean SRTs were around 3 dB better with bimodal presentation than with CI alone in overlap configurations. A spherical head model was used to simulate azimuthal separation of speech and noise and provided no evidence of a contribution of spatial cues to bimodal benefit. There was no effect on bimodal performance of whether spectral overlap was present or was eliminated by switching off electrodes assigned to frequencies below the upper limit of acoustic hearing. In a subsequent experiment the CI was acutely re-mapped so that all available electrodes were used to cover frequencies not presented acoustically. This gave increased spectral resolution via the CI as assessed by formant frequency discrimination, but no improvement in bimodal performance compared to the configuration with overlap.
authors.affiliation: Speech, Hearing, and Phonetic Sciences, UCL, Chandler House, 2, Wakefield Street, London, WC1N 1PF, United Kingdom.
authors.forename: Tim
authors.initials: T
authors.lastname: Green
authors.affiliation: Speech, Hearing, and Phonetic Sciences, UCL, Chandler House, 2, Wakefield Street, London, WC1N 1PF, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Faulkner
authors.affiliation: Speech, Hearing, and Phonetic Sciences, UCL, Chandler House, 2, Wakefield Street, London, WC1N 1PF, United Kingdom.
authors.forename: Stuart
authors.initials: S
authors.lastname: Rosen
mesh_terms: D000161:Acoustic Stimulation; D000368:Aged; D000369:Aged, 80 and over; D001309:Auditory Threshold; D019929:Cochlear Implantation / Q000295:instrumentation*; D003054:Cochlear Implants; D003463:Cues; D004558:Electric Stimulation; D006801:Humans; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*; D011474:Prosthesis Design; D021641:Recognition, Psychology; D013028:Space Perception; D013065:Speech Intelligibility; D013067:Speech Perception; D013069:Speech Reception Threshold Test