title: Sound Source Localization by Normal-Hearing Listeners, Hearing-Impaired Listeners and Cochlear Implant Listeners.
abstract: Our primary aim was to determine whether listeners in the following patient groups achieve localization accuracy within the 95th percentile of accuracy shown by younger or older normal-hearing (NH) listeners: (1) hearing impaired with bilateral hearing aids, (2) bimodal cochlear implant (CI), (3) bilateral CI, (4) hearing preservation CI, (5) single-sided deaf CI and (6) combined bilateral CI and bilateral hearing preservation.
  
  
  
  The listeners included 57 young NH listeners, 12 older NH listeners, 17 listeners fit with hearing aids, 8 bimodal CI listeners, 32 bilateral CI listeners, 8 hearing preservation CI listeners, 13 single-sided deaf CI listeners and 3 listeners with bilateral CIs and bilateral hearing preservation. Sound source localization was assessed in a sound-deadened room with 13 loudspeakers arrayed in a 180-degree arc.
  
  
  
  The root mean square (rms) error for the NH listeners was 6 degrees. The 95th percentile was 11 degrees. Nine of 16 listeners with bilateral hearing aids achieved scores within the 95th percentile of normal. Only 1 of 64 CI patients achieved a score within that range. Bimodal CI listeners scored at a level near chance, as did the listeners with a single CI or a single NH ear. Listeners with (1) bilateral CIs, (2) hearing preservation CIs, (3) single-sided deaf CIs and (4) both bilateral CIs and bilateral hearing preservation, all showed rms error scores within a similar range (mean scores between 20 and 30 degrees of error).
  
  
  
  Modern CIs do not restore a normal level of sound source localization for CI listeners with access to sound information from two ears.
authors.affiliation: Arizona State University, Tempe, Ariz., USA.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Dorman
authors.forename: Louise H
authors.initials: LH
authors.lastname: Loiselle
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Cook
authors.forename: William A
authors.initials: WA
authors.lastname: Yost
authors.forename: René H
authors.initials: RH
authors.lastname: Gifford
mesh_terms: D000328:Adult; D000368:Aged; D001307:Auditory Perception; D016022:Case-Control Studies; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D005260:Female; D006310:Hearing Aids; D034381:Hearing Loss / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013017:Sound Localization; D013067:Speech Perception; D055815:Young Adult