title: Influence of cochlear implant insertion depth on performance: a prospective randomized trial.
abstract: OBJECTIVE
  The purpose of the present study was to assess the influence of electrode insertion length on cochlear implant (CI) performance.
  
  
  METHODS
  Prospective randomized allocation of CI patients to receive either a standard (26.4 mm)- or medium (20.9 mm)-length electrode array. The processing strategy and electrode insertion number were held constant. The postoperative testing audiologist was blinded to the map details and array.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  Thirteen adult CI candidates randomized to receive the standard- (n = 7) or medium-length (n = 6) electrode array.
  
  
  METHODS
  Unilateral CI using standard- or medium-length array from the same implant system.
  
  
  METHODS
  Speech perception was assessed with HINT sentences in quiet and steady-state noise (SNR, +10) and CNC words in quiet at defined intervals. Quality of life was assessed using the Hearing Device Satisfaction Survey and the Abbreviated Profile of Hearing Aid Benefit (APHAB). Music perception was assessed using the Musical Sounds In Cochlear implants (MuSIC) test. Postoperative electrode insertion angle was assessed using reconstructed computed tomographic images.
  
  
  RESULTS
  Interim analysis necessitated discontinuation of subject enrollment by the institutional review board. There was a trend (p = 0.07) for improved speech perception performance among standard array patients. This difference was significant when the standard array group was increased retrospectively. Quality of life and music perception differences were not apparent between groups.
  
  
  CONCLUSIONS
  Longer electrode insertions (and greater insertion angles) appear to offer better speech perception performance in the early postactivation period when using the same implant system.
authors.affiliation: *Department of Otolaryngology/Head and Neck Surgery, University of North Carolina at Chapel Hill; and †Department of Audiology, University of North Carolina Heath Care, North Carolina, U.S.A.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Buchman
authors.forename: Margaret T
authors.initials: MT
authors.lastname: Dillon
authors.forename: English R
authors.initials: ER
authors.lastname: King
authors.forename: Marcia C
authors.initials: MC
authors.lastname: Adunka
authors.forename: Oliver F
authors.initials: OF
authors.lastname: Adunka
authors.forename: Harold C
authors.initials: HC
authors.lastname: Pillsbury
mesh_terms: D000368:Aged; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009146:Music; D011184:Postoperative Period; D011446:Prospective Studies; D011788:Quality of Life; D013067:Speech Perception / Q000502:physiology*; D016896:Treatment Outcome