Variables Affecting Cochlear Implant Performance After Loss of Residual Hearing

Abstract

ObjectiveDetermine variables that influence post‐activation performance for cochlear implant (CI) recipients who lost low‐frequency acoustic hearing.MethodsA 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.Results113 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.ConclusionCI 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 EvidenceLevel IV Laryngoscope, 2023