Conductive component after cochlear implantation in patients with residual hearing conservation

Am J Audiol. 2014 Dec;23(4):359-64. doi: 10.1044/2014_AJA-14-0018.

Abstract

Purpose: Changes in auditory thresholds following cochlear implantation are generally assumed to be due to damage to neural elements. Theoretical studies have suggested that placement of a cochlear implant can cause a conductive hearing loss. Identification of a conductive component following cochlear implantation could guide improvements in surgical techniques or device designs. The purpose of this study is to characterize new-onset conductive hearing losses after cochlear implantation.

Method: In a prospective study, air- and bone-conduction audiometric testing were completed on cochlear implant recipients. An air-bone gap equal to or greater than 15 dB HL at 2 frequencies determined the presence of a conductive component.

Results: Of the 32 patients with preoperative bone-conduction hearing, 4 patients had a new-onset conductive component resulting in a mixed hearing loss, with air-conduction thresholds ranging from moderate to profound and an average air-bone gap of 30 dB HL. One had been implanted through the round window, 2 had an extended round window, and 1 had a separate cochleostomy.

Conclusions: Loss of residual hearing following cochlear implantation may be due in part to a conductive component. Identifying the mechanism for this conductive component may help minimize hearing loss. Postoperative hearing evaluation should measure both air- and bone-conduction thresholds.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged, 80 and over
  • Audiometry
  • Auditory Threshold
  • Bone Conduction
  • Cochlear Implantation* / adverse effects
  • Cochlear Implantation* / methods
  • Female
  • Hearing Loss / surgery
  • Hearing Loss, Conductive / etiology*
  • Hearing Loss, Sensorineural / surgery
  • Humans
  • Male
  • Middle Aged
  • Prospective Studies