Hearing preservation in 41 cochlear implant recipients with preimplant low-frequency residual hearing.

Abstract

Background: Hearing preservation (HP) is an important objective in cochlear implantation for patients with residual low-frequency hearing, but its long-term clinical relevance remains uncertain.

Objective: To evaluate long-term hearing preservation, functional residual hearing, and speech recognition following cochlear implantation.

Material and methods: This retrospective cohort study included 41 adults (42 ears) with a preoperative low-frequency pure-tone average (LFPTA) ≤80 dB HL. Hearing preservation was assessed using the HEARRING and low-frequency threshold shift (dPTA) classifications. Linear mixed-effects models evaluated longitudinal changes in LFPTA and speech recognition, and Kaplan-Meier analysis estimated retention of functional residual hearing.

Results: Hearing preservation was frequently achieved according to both classification systems. LFPTA deteriorated by 20.5 dB HL during the first 6 postoperative months and declined by 2.46 dB HL annually thereafter (p = 0.020). Functional residual hearing decreased from 66.7% to 41.7% during follow-up. In contrast, speech recognition improved significantly after implantation (all p < 0.001) and remained stable. Retained functional residual hearing was not associated with superior speech recognition.

Conclusions and significance: Although residual hearing declined progressively, speech recognition remained robust irrespective of retained functional residual hearing. Hearing preservation remains a worthwhile surgical objective but was not associated with improved long-term speech recognition.