title: Having Two Ears Facilitates the Perceptual Separation of Concurrent Talkers for Bilateral and Single-Sided Deaf Cochlear Implantees.
abstract: Listening to speech with multiple competing talkers requires the perceptual separation of the target voice from the interfering background. Normal-hearing listeners are able to take advantage of perceived differences in the spatial locations of competing sound sources to facilitate this process. Previous research suggests that bilateral (BI) cochlear-implant (CI) listeners cannot do so, and it is unknown whether single-sided deaf (SSD) CI users (one acoustic and one CI ear) have this ability. This study investigated whether providing a second ear via cochlear implantation can facilitate the perceptual separation of targets and interferers in a listening situation involving multiple competing talkers.
  
  
  
  BI-CI and SSD-CI listeners were required to identify speech from a target talker mixed with one or two interfering talkers. In the baseline monaural condition, the target speech and the interferers were presented to one of the CIs (for the BI-CI listeners) or to the acoustic ear (for the SSD-CI listeners). In the bilateral condition, the target was still presented to the first ear but the interferers were presented to both the target ear and the listener's second ear (always a CI), thereby testing whether CI listeners could use information about the interferer obtained from a second ear to facilitate perceptual separation of the target and interferer.
  
  
  
  Presenting a copy of the interfering signals to the second ear improved performance, up to 4 to 5 dB (12 to 18 percentage points), but the amount of improvement depended on the type of interferer. For BI-CI listeners, the improvement occurred mainly in conditions involving one interfering talker, regardless of gender. For SSD-CI listeners, the improvement occurred in conditions involving one or two interfering talkers of the same gender as the target. This interaction is consistent with the idea that the SSD-CI listeners had access to pitch cues in their normal-hearing ear to separate the opposite-gender target and interferers, while the BI-CI listeners did not.
  
  
  
  These results suggest that a second auditory input via a CI can facilitate the perceptual separation of competing talkers in situations where monaural cues are insufficient to do so, thus partially restoring a key advantage of having two ears that was previously thought to be inaccessible to CI users.
authors.affiliation: 1National Military Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland, USA; 2Department of Hearing and Speech Sciences, University of Maryland-College Park, College Park, Maryland, USA; and 3Department of Otolaryngology Head and Neck Surgery, Walter Reed National Military Medical Center, Bethesda, Maryland, USA.
authors.forename: Joshua G W
authors.initials: JG
authors.lastname: Bernstein
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Goupell
authors.forename: Gerald I
authors.initials: GI
authors.lastname: Schuchman
authors.forename: Arnaldo L
authors.initials: AL
authors.lastname: Rivera
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Brungart
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D019929:Cochlear Implantation; D003638:Deafness / Q000534:rehabilitation*; D005260:Female; D046088:Hearing Loss, Unilateral / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013017:Sound Localization; D013067:Speech Perception