Depth of Cochlear Implant Array Within the Cochlea and Performance Outcome

Ohad Hilly*, Leah Smith, Euna Hwang, David Shipp, Sean Symons, Julian M. Nedzelski, Joseph M. Chen, Vincent Y.W. Lin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Objective: To evaluate whether the depth of cochlear implant array within the cochlea affects performance outcomes 1 year following cochlear implantation. Methods: A retrospective case review of 120 patients who were implanted with the Advanced Bionics HiFocus 1J. Post-implantation plain-radiographs were retrospectively reviewed, and the depth of insertion was measured in degrees from the round window to the electrode tip. Correlation between the depth of insertion and 1-year post-activation Hearing in Noise Test (HINT) scores was analyzed. Intrascala position was not assessed. Results: Depth of electrode insertion ranged from 180° to 720°, and HINT scores ranged from 0% to 100%. A Mann-Whitney U test demonstrated significantly improved 1-year post-activation HINT scores in patients with an insertion depth of 360° or more in comparison with patients with insertion depth of less than 360° (81% vs 61%, P =.048). Patients with 13 to 15 contacts within cochlear turns performed as well as patients with full insertion of all 16 contacts, while patients with only 12 contacts performed poorly. Conclusions: Insertion depth of the AB HiFocus 1J electrode of less than 360° is associated with reduced 1-year post-activation HINT scores when compared with deeper insertions. Partial insertion of 13 active contacts or more led to similar results as full insertion.

Original languageEnglish
Pages (from-to)886-892
Number of pages7
JournalAnnals of Otology, Rhinology and Laryngology
Issue number11
StatePublished - 1 Nov 2016


  • Cochlear implantation
  • cochlear implant trials
  • depth of insertion
  • hearing in noise test
  • outcome


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