title: Implication of central asymmetry in speech processing on selecting the ear for cochlear implantation.
abstract: OBJECTIVE
  Emerging evidence in auditory neuroscience suggests that central auditory pathways process speech asymmetrically. In concert with left cortical specialization for speech, a "right-ear advantage" in speech perception has been identified. The purpose of this study is to determine if this central asymmetry in speech processing has implications for selecting the ear for cochlear implantation.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Academic university medical center
  
  
  METHODS
  One hundred one adults with bilateral severe-to-profound sensorineural hearing loss
  
  
  METHODS
  Cochlear implantation with the Nucleus 24 Contour device.
  
  
  METHODS
  Patients were divided into two groups according to the ear implanted. Results were compared between left-ear- and right-ear-implanted patients. Further subgroup analysis was undertaken, limited to right-handed patients. Postoperative improvement on audiograms and scores on speech perception tests (Hearing in Noise test, City University of New York in quiet and in noise test, Consonant-Vowel Nucleus- Consonant words, and phonemes) at 1 year was compared between groups. Analysis of covariance was used to control for any intergroup differences in preoperative characteristics.
  
  
  RESULTS
  The groups were matched in age, duration of hearing loss, duration of hearing aid use, percentage implanted in the better hearing ear, and preoperative audiologic testing. Postoperatively, there were no differences between left-ear- and right-ear-implanted patients in improvement on speech recognition tests.
  
  
  CONCLUSIONS
  Despite central asymmetry in speech processing, our data do not support a right-ear advantage in speech perception outcomes with cochlear implantation. Therefore, among the many factors in choosing the ear for cochlear implantation, central asymmetry in speech processing does not seem to be a contributor to postoperative speech recognition outcomes.
authors.affiliation: Department of Otolaryngology and Cochlear Implant Center, New York University School of Medicine, New York, New York 10016, USA.
authors.forename: Luc G
authors.initials: LG
authors.lastname: Morris
authors.forename: Pavan S
authors.initials: PS
authors.lastname: Mallur
authors.forename: J Thomas
authors.initials: JT
authors.lastname: Roland
authors.forename: Susan B
authors.initials: SB
authors.lastname: Waltzman
authors.forename: Anil K
authors.initials: AK
authors.lastname: Lalwani
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001301:Audiometry, Pure-Tone; D019929:Cochlear Implantation / Q000295:instrumentation; D015331:Cohort Studies; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006319:Hearing Loss, Sensorineural / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013067:Speech Perception / Q000502:physiology*; D016896:Treatment Outcome