Cochlear Health Monitoring Post-Cochlear Implantation Reveals Biomarkers for Hearing Outcomes

OBJECTIVES: This study aims to elucidate the timing and mechanisms associated with postoperative residual hearing loss following cochlear implantation and to assess the feasibility of clinical tools designed for prospective cochlear health monitoring. DESIGN: A prospective clinical cohort investigation was conducted utilizing patient-administered in-home cochlear health monitoring to track electrocochleography (ECochG) and four-point impedance (4PI) fluctuations during the first three postoperative months. RESULTS: The study included 32 subjects who completed the in-home testing over the first 3 months following cochlear implantation. ECochG markers identified during real-time ECochG monitoring of electrode insertion correlated with poorer hearing preservation outcomes (Skarzynski hearing preservation scores [mean hearing preservation: 56.88 versus 38.91%, p = 0.0328]) and higher impedances recorded on in-home testing (peak median 4PI: 398.46 Ω versus 270.75 Ω, p = 0.0478). Drops in cochlear microphonic (CM) amplitude detected through in-home monitoring were associated with poorer hearing preservation (mean LFPTM loss: 31.45 versus 11.78 dB, p = 0.0003) and higher impedance values (431.3 Ω versus 262.9 Ω, p = 0.0047). The study identified significant markers of hearing preservation in CM amplitude and 4PI, detectable through postoperative in-home monitoring. CONCLUSIONS: Patient-initiated in-home monitoring of cochlear health biomarkers is feasible and provides valuable insights into the recovery of inner ear function following CI. The identified markers, CM amplitude, and 4PI have the potential to personalize postoperative care and improve hearing preservation outcomes.