Quality of Life Impact of Cochlear Implantation for Single-Sided Deafness: Assessing the Interrelationship of Objective and Subjective Measures

Abstract

Objective To determine the effect on quality of life (QOL) of cochlear implantation (CI) for single-sided deafness (SSD) and asymmetric hearing loss (AHL) using the first psychometrically developed CI-specific QOL tool for English-speaking patients and to assess its relationship to objective perceptual measures. Study Design Retrospective cohort study. Setting Tertiary-care medical center. Patients English-speaking adults with SSD or AHL. Interventions Unilateral CI. Main Outcome Measures Cochlear Implant Quality of Life (CIQOL) score, CI-alone speech-in-quiet (SIQ) score (CNC and AzBio), binaural speech-in-noise (SIN) threshold, binaural azimuthal sound localization (SL) error. Results At the most recent postoperative evaluation (median, 9.3 months postimplantation), 25 of 28 subjects (89%) had a CIQOL improvement, with the improvement considered clinically beneficial (>3 points) for 18 of 28 subjects (64%). Group-mean CIQOL improvement was observed at the first postoperative visit and did not change significantly thereafter. Objective perceptual measures (SL, SIQ, SIN) continued to improve over 12 months after implantation. Linear mixed-model regression analyses showed a moderate positive correlation between SIN and SIQ improvements (r = 0.50 to 0.59, p < 0.0001) and a strong positive correlation between the improvement in the two SIQ measures (r = 0.89, p < 0.0001). No significant relationships were observed (p > 0.05) among QOL or the objective perceptual measures. Conclusions QOL improved for the majority of subjects implanted for SSD and AHL. Different time courses for improvement in QOL and audiologic tests, combined with the lack of significant relationships among them, suggest that QOL outcomes reflect different aspects of the CI experience than those captured by speech-understanding and localization measures. SIQ may substitute for SIN when clinical constraints exist.