Outcomes of Cochlear Implantation for Single-Sided Deafness and Asymmetric Hearing Loss: Quality of Life, Tinnitus, and the Effect of Deafness Duration.
Abstract
Objectives. To evaluate multidimensional outcomes of cochlear implantation (CI) in adults with single-sided deafness (SSD) or asymmetric hearing loss (AHL), and to examine how duration of deafness influences speech perception, tinnitus severity, and hearing-related quality of life. Methods. This retrospective cohort study included 124 adults with SSD or AHL who underwent unilateral CI at a tertiary referral center (September 2019-October 2024) with at least 12 months of postoperative follow-up. The primary outcome, hearing-related quality of life, was assessed using the Speech, Spatial, and Qualities of Hearing Scale (SSQ); secondary outcomes included the Hearing Handicap Inventory for the Elderly (HHIE), Tinnitus Handicap Inventory (THI), Short Form-36 (SF-36), and open-set speech perception (n = 61). The association between duration of deafness and postoperative outcomes was evaluated using duration as a continuous predictor in linear regression. Results. Significant postoperative improvements occurred in SSQ Speech (+0.97; d = 0.53; p < 0.001) and Spatial domains (+1.60; d = 0.88; p < 0.001), HHIE (- 13.0; d = 0.50; p < 0.001), THI (-15.8; d = 0.61; p < 0.001), and SF-36 (+4.2; d = 0.27; p = 0.031). Speech perception improved markedly under CI-only conditions (monosyllabic d = 1.98; bisyllabic d = 2.92; sentence recognition d = 3.59). Longer duration of deafness was significantly associated with smaller THI improvement (β = 1.13 points/year, 95% CI 0.43-1.84; p = 0.002; adjusted β = 0.98, 95% CI 0.18-1.78; p = 0.017), whereas quality-of-life and sentence recognition outcomes were not associated with deafness duration. Conclusion. Unilateral CI produces clinically meaningful improvements in hearingrelated quality of life, tinnitus severity, hearing handicap, and speech perception in adults with SSD and AHL. Quality-of-life and speech outcomes were preserved regardless of deafness duration, whereas tinnitus suppression declined with increasing deaf duration. These findings support earlier CI for candidates with bothersome tinnitus.