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Updated: Nov 30, 2025
Performing Intracochlear Electrocochleography During Cochlear Implantation
Published on: March 8, 2022
Electrocochleography Observations in a Series of Cochlear Implant Electrode Tip Fold-Overs
Eleonora M C Trecca1,2, Oliver F Adunka1, Jameson K Mattingly1
1Department of Otolaryngology - Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
Objective:
Tip fold-over is a rare but serious complication of cochlear implant (CI) surgery. The purpose of this study was to present intraoperative electrocochleography (ECochG) observations in a series of CI electrode tip fold-overs.
Patients:
Five pediatric subjects undergoing CI surgery through a round window (RW) approach with a perimodiolar electrode array, who were diagnosed with either auditory neuropathy spectrum disorder or enlarged vestibular aqueduct.
Interventions:
Intraoperative RW ECochG during CI surgery: tone burst stimuli were presented from 95 to 110 dB SPL.
Main Outcome Measures:
Magnitude and phase characteristics of ECochG responses obtained intraoperatively before and immediately after electrode insertion were examined for patients with and without tip fold-over.
Results:
Three subjects presented with tip fold-over and two formed the control group. Among fold-over cases, one participant exhibited an inversion in the starting phase of the cochlear microphonic response and a decrease in spectral magnitude from pre- to postinsertion. Both subjects who did not exhibit a change in phase had an increase in the ECochG-total response (ECochG-TR) magnitude. No case in the control group exhibited a change in starting phase. In regard to the ECochG-TR, all controls showed a decrease in the magnitude.
Conclusions:
Despite the small number of patients, heterogeneous ECochG response patterns were observed within the fold-over group. Though these results are not conclusive, they can serve as a framework to begin to understand ECochG's utility in detecting intraoperative tip fold-over.
