Evaluation of Real-Time Intracochlear Electrocochleography for Guiding Cochlear Implant Electrode Array Position

Area of Science:

• Otoacoustic Emissions and Auditory Evoked Potentials
• Neurosurgery and Otolaryngology

Background:

• Real-time monitoring during cochlear implantation is crucial for preserving hearing.
• Intracochlear electrocochleography (ECochG) is a potential tool for intraoperative monitoring.
• The interpretation of ECochG signals can be confounded by the recording electrode's position.

Purpose of the Study:

• To evaluate intracochlear ECochG for real-time monitoring during cochlear implantation.
• To determine if adjusting the recording electrode site can differentiate atraumatic from traumatic ECochG amplitude decrements.
• To assess if considering hearing sensitivity at the ECochG stimulus frequency improves the association with post-operative hearing loss.

Main Methods:

• Single-frequency (500-Hz) ECochG was performed in 11 adult cochlear implant recipients.
• The amplitude of the first harmonic of the difference waveform was analyzed.
• Post-operative hearing preservation was assessed at 500 Hz.

Main Results:

• A trend between ECochG amplitude decrements and hearing preservation was observed but not statistically significant.
• Predictions of hearing preservation were inaccurate for two participants.
• Considering alternative recording sites or broader frequency ranges did not improve the association between ECochG decrements and hearing loss.

Conclusions:

• Intracochlear recording electrode location is a significant confounder for real-time ECochG interpretation.
• Multiple factors influence ECochG amplitude patterns and hearing preservation.
• The study highlights the confounding effect of intracochlear electrode placement on ECochG during cochlear implantation.