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Updated: Jan 15, 2026
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Performing Intracochlear Electrocochleography During Cochlear Implantation
Published on: March 8, 2022
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Bilocated Intracochlear Electrocochleography During Cochlear Implantation to Provide Surgical Feedback
Leanne Sijgers1, Rahel Bertschinger, Marlies Geys
1Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Summary
Simultaneous intracochlear electrocochleography (ECochG) using two electrode contacts helps differentiate atraumatic from traumatic changes during cochlear implantation, aiding hearing preservation efforts.
Area of Science:
- Otoacoustic Emissions and Electrophysiology
- Neurosurgery and Otolaryngology
- Auditory Neuroscience
Background:
- Intracochlear electrocochleography (ECochG) is vital for intraoperative surveillance during cochlear implantation (CI) to minimize surgical trauma and preserve hearing.
- Interpreting ECochG signal changes during electrode insertion is challenging due to varied response generator distribution within the cochlea.
Purpose of the Study:
- To investigate if simultaneous ECochG recordings from two intracochlear locations can improve the interpretation of signal changes during CI electrode insertion.
- To compare ECochG responses from apical and basal electrode contacts during atraumatic insertions.
- To correlate intracochlear ECochG patterns with preoperative pure-tone audiograms.
Main Methods:
- ECochG recordings were obtained from 10 CI recipients using a temporary electrode array with two contacts separated by 4.2 mm.
- Simultaneous recordings were made in response to 500 Hz tone bursts, with ECochG responses derived from alternating-polarity stimuli.
- ECochG response patterns were analyzed and compared between electrode contacts and with preoperative audiograms.
Main Results:
- In 60% of participants, amplitude decreases (≥3 dB) were observed at the basal electrode contact.
- In 40% of cases, basal electrode drops were preceded by apical electrode drops, occurring within 1.7 mm, suggesting atraumatic insertion.
- Atraumatic drops, potentially linked to phase shifts, were distinguished from simultaneous drops expected during trauma; ECochG patterns showed limited correlation with audiograms.
Conclusions:
- The proposed dual-contact ECochG approach aids in detecting relevant response changes for predicting hearing preservation during CI.
- Distinguishing between simultaneous and sequential amplitude drops offers insights into the atraumatic nature of ECochG changes.
- This method enhances intraoperative decision-making for optimizing hearing outcomes in cochlear implantation.
