Multi-Frequency Electrocochleography Results in Fewer Drop Alarms During Cochlear Implant Insertion.

Abstract

To evaluate intracochlear electrocochleography (ECochG) amplitude parameters during cochlear implantation (CI) using a novel multi-frequency ECochG algorithm. A multi-institutional, prospective cohort study was performed at 18 high-volume CI centers. The inclusion criteria were adults with sensorineural hearing loss and audiometric thresholds of ≤ 90 dB hearing level at 500 Hz undergoing CI with Advanced Bionics (Valencia, CA) Ultra 3D devices between 2024 and 2025. ECochG recordings were performed with simultaneous multi-frequency stimulation of four frequencies between 125 and 4000 Hz during cochlear implant insertion. Concurrent multi-frequency recording allowed extraction of amplitude and phase of each frequency individually. Post hoc analysis was performed to determine the difference in the number of drop alarms between single- and multi-frequency ECochG. An ECochG amplitude drop of 6 dB was defined as a drop alarm. Insertion track patterns were compared between single- and multi-frequency ECochG. One hundred ninety-five ears were included. Mean number of drop alarms for the single-frequency algorithm was 1.72 (95% CI: 1.52, 1.92; median 1) compared to 0.42 (95% CI: 0.31, 0.53; median 0) for multi-frequency; p < 0.001. The number of Type C patterns (rise in amplitude during insertion followed by a drop) decreased with the multi-frequency ECochG algorithm compared to the single-frequency ECochG algorithm. The number of Type D patterns (no-response) decreased, indicating that multi-frequency ECochG generated more responses across the cochlea than single-frequency ECochG. A novel multi-frequency ECochG algorithm during CI is associated with fewer drop alarms and altered insertion track patterns, which may provide a more accurate assessment of the cochlear microenvironment.