Durability of Hearing Preservation after Cochlear Implantation with Conventional-Length Electrodes and Scala Tympani Insertion

Otolaryngol Head Neck Surg. 2016 May;154(5):907-13. doi: 10.1177/0194599816630545. Epub 2016 Feb 23.


Objectives: To analyze factors that influence hearing preservation over time in cochlear implant recipients with conventional-length electrode arrays located entirely within the scala tympani.

Study design: Case series with planned chart review.

Setting: Single tertiary academic referral center.

Subjects and methods: A retrospective review was performed to analyze a subgroup of cochlear implant recipients with residual acoustic hearing. Patients were included in the study only if their electrode arrays remained fully in the scala tympani after insertion and serviceable acoustic hearing (≤80 dB at 250 Hz) was preserved. Electrode array location was verified through a validated radiographic assessment tool. Patients with <6 months of audiologic follow-up were excluded. The main outcome measure was change in acoustic hearing thresholds from implant activation to the last available follow-up.

Results: A total of 16 cases met inclusion criteria (median age, 70.6 years; range, 29.4-82.2; 50% female). The average follow-up was 18.0 months (median, 16.1; range, 6.2-36.4). Patients with a lateral wall electrode array were more likely to have stable acoustic thresholds over time (P < .05). Positive correlations were seen between continued hearing loss following activation and larger initial postoperative acoustic threshold shifts, though statistical significance was not achieved. Age, sex, and noise exposure had no significant influence on continued hearing preservation over time.

Conclusions: To control for hearing loss associated with interscalar excursion during cochlear implantation, the present study evaluated patients only with conventional electrode arrays located entirely within the scala tympani. In this group, the style of electrode array may influence residual hearing preservation over time.

Keywords: cochlear implantation; cochlear trauma; hearing preservation; image guidance.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Audiology
  • Auditory Threshold
  • Cochlear Implantation*
  • Cochlear Implants*
  • Electrodes, Implanted*
  • Female
  • Hearing Loss / prevention & control*
  • Humans
  • Male
  • Middle Aged
  • Retrospective Studies
  • Scala Tympani / surgery*
  • Treatment Outcome