Variables Affecting Cochlear Implant Performance After Loss of Residual Hearing.

Objective: Determine variables that influence post‐activation performance for cochlear implant (CI) recipients who lost low‐frequency acoustic hearing. Methods: A retrospective review evaluated CNC word recognition for adults with normal to moderately severe low‐frequency hearing (preoperative unaided thresholds of ≤70 dB HL at 250 Hz) who were implanted between 2012 and 2021 at a tertiary academic center, lost functional acoustic hearing, and were fit with a CI‐alone device. Performance scores were queried from the 1, 3, 6, 12, and 24‐month post‐activation visits. A linear mixed model evaluated the effects of age at implantation, array length (long vs. mid/short), and preoperative low‐frequency hearing (normal to mild, moderate, and moderately severe) on speech recognition with a CI alone. Results: 113 patients met the inclusion criteria. There was a significant main effect of interval (p < 0.001), indicating improved word recognition post‐activation despite loss of residual hearing. There were significant main effects of age (p = 0.029) and array length (p = 0.038), with no effect of preoperative low‐frequency hearing (p = 0.171). There was a significant 2‐way interaction between age and array length (p = 0.018), indicating that older adults with mid/short arrays performed more poorly than younger adults with long lateral wall arrays when functional acoustic hearing was lost. Conclusion: CI recipients with preoperative functional low‐frequency hearing experience a significant improvement in speech recognition with a CI alone as compared to preoperative performance—despite the loss of low‐frequency hearing. Age and electrode array length may play a role in post‐activation performance. These data have implications for the preoperative counseling and device selection for hearing preservation candidates. Level of Evidence: 4 Laryngoscope, 134:1868–1873, 2024 [ABSTRACT FROM AUTHOR]