Caloric function as a predictor of cochlear implant performance

Abstract

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.