Caloric function as a predictor of cochlear implant performance.

Objectives: Changes in vestibular function have been demonstrated following cochlear implantation (CI). The functional impact of these changes on CI performance has not been well-studied. We sought to assess whether caloric changes postimplantation could predict CI performance.

Methods: Retrospective review of a prospectively collected database at a tertiary care hospital. Patients who underwent CI over a 22-year period (1999-2021) and had videonystagmography (VNG) testing pre- and postimplantation were included. Caloric responses were compared pre- versus post-implantation, and assessed for their ability to predict CI performance as evaluated using AzBio +10 decibels signal-to-noise ratio (dB S/N) scores.

Results: 43 CI recipients were included. There was a significant difference in the average maximal slow-phase velocity in response to caloric irrigation in the implanted ear pre- versus post-operatively (21.2 vs. 18.5 deg/s; p = 0.02). Controlling for age and pre-implantation speech recognition performance, pre- and post-implantation caloric responses in the implanted ear significantly predicted CI performance at 0-6 months and >6 months post-implantation. Caloric changes following implantation were not significantly correlated with CI performance.

Conclusion: CI impacts vestibular function as evidenced by changes in caloric responses. Vestibular function pre- and possibly post-CI may be clinically useful metrics for predicting some proportion of CI performance variability.