Characterizing the Impact of Prolonged Deafness Duration on Cochlear Implantation Performance

OBJECTIVE: To evaluate the impact of prolonged unaided duration of deafness (DoD) on speech perception outcomes following cochlear implantation in adults. METHODS: A retrospective review was performed of adult cochlear implant recipients at a single high-volume center between 2012 and 2023. Patients with ≥ 5 years of documented unaided deafness meeting cochlear implant (CI) criteria were stratified into three groups (5-9, 10-19, and ≥ 20 years DoD). The primary outcome was CNC word recognition scores at 3 and 12 months post-operatively. RESULTS: Forty-one patients met inclusion criteria. At 3 months, patients with ≥ 20 years DoD demonstrated lower CNC word recognition scores compared with shorter duration groups. No significant differences were observed between groups at 12 months. Patients without measurable pre-operative hearing thresholds were more likely to be device non-users or fail to achieve open-set speech perception. CONCLUSION: Patients demonstrated meaningful speech perception outcomes across a range of deafness durations, though longer DoD was associated with slower early improvement. Absence of measurable pre-operative hearing thresholds may identify a subgroup at higher risk for limited functional benefit and should be considered during pre-operative counseling.