title: Perception of polyphony with cochlear implants for 2 and 3 simultaneous pitches.
abstract: OBJECTIVE
  It was hypothesized that cochlear implant (CI) subjects would be able to correctly identify 1, 2, and 3 simultaneous pitches through direct electrical stimulation. We further hypothesized that the location on the implant array and the fundamental frequency of the pitches would have an impact on the performance.
  
  
  BACKGROUND
  "They gave me back speech but not music" is a sentence commonly heard by CI subjects. One of the reasons is that in music, multiple streams are frequently played at the same time, which is an essential feature of harmony. Current CI speech processors do not allow CI users to perceive such complex polyphonic sounds.
  
  
  METHODS
  In the present study, the authors assessed the ability of CI subjects to perceive simultaneous modulation frequencies based on direct electrical stimulation. Ten CI subjects were asked to identify 1, 2, and 3 simultaneous pitches applied on different electrodes using sinusoidal amplitude modulation. All stimuli were loudness balanced before the actual identification task.
  
  
  RESULTS
  Subjects were able to identify 1, 2, and 3 simultaneous pitches. The further the distance between the 2 electrodes, the better was the performance in the 2-pitch condition. The distance between the modulation frequencies had a significant effect on the performance in the 2-and 3-pitch condition.
  
  
  CONCLUSIONS
  Subjects are able to identify complex polyphonic stimuli based on the number of active electrodes. The additional polyphonic rate pitch cue improves performance in some conditions.
authors: *Institute for Psychoacoustics and Electronic Music, University Ghent, Ghent, Belgium; †Cluster of Excellence "Hearing4all" Department of Otolaryngology, Medical University of Hannover, Hannover, Germany; ‡Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins Hospital, Baltimore, Maryland, U.S.A.; §Peabody Conservatory of Music, Baltimore, Maryland, U.S.A.; and ∥Department of Otolaryngology, University Hospital Ghent, Ghent, Belgium.
authors: Richard T
authors: RT
authors: Penninger
authors: Eugen
authors: E
authors: Kludt
authors: Charles J
authors: CJ
authors: Limb
authors: Marc
authors: M
authors: Leman
authors: Ingeborg
authors: I
authors: Dhooge
authors: Andreas
authors: A
authors: Buechner
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D019929:Cochlear Implantation; D003054:Cochlear Implants; D003638:Deafness / Q000503:physiopathology / Q000601:surgery*; D004558:Electric Stimulation; D006801:Humans; D008875:Middle Aged; D009146:Music; D010898:Pitch Perception / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*