Comparison of Speech Test Outcomes After Cochlear Implantation in Patients With and Without Asymmetric Hearing Loss

Objectives: Determine whether asymmetric hearing loss (AHL) affects postoperative speech outcomes in cochlear implant (CI) patients. Study Design: Retrospective cohort study. Setting: Tertiary care hospital. Patients: Adult English-speaking patients with unilateral CIs implanted between 2014 and 2018 were stratified into NonAHL and AHL groups based on preoperative AzBio scores in quiet from the nonimplanted ear (0-50% vs. 51-100%, respectively). Interventions: CI surgery in the poorer performing ear. Main Outcome Measures: Postoperative consonant-nucleusconsonant (CNC) word and AzBio sentence test scores in quiet and/or noise at +5 dB signal-to-noise ratio (SNR). Results: Of 512 patients, 33 non-AHL and 27 AHL patients were included. Average ages were 65.6 and 63.6 years, respectively. As expected, preoperative AzBio scores in quiet from the nonimplanted ear were higher in the AHL group (95% confidence interval [95%CI]: 66.4-76.4%) than the non-AHL group at baseline (95%CI: 12.3-23.6%). In both cohorts, AzBio scores in quiet from the implanted ear improved from baseline, with 24-month scores (95%CI: 73.8 - 84.9%) being higher than preoperative scores (95%CI: 13.2-23.1%). There were also significant differences in AzBio scores in quiet between cohorts overall (p = 0.0120) on mixed model analysis, with the AHL group performing similar to 6.4% better than the non-AHL group; however, differences were not significant when scores were stratified by time. In addition, there were no significant differences in CNC in quiet and AzBio scores in noise at +5 dB SNR between cohorts (p = 0.1786 and p = 0.6215, respectively). Conclusions: After CI, patients with AHL can achieve scores on word and sentence tests at least comparable to traditional CI candidates, supporting the expansion of CI candidacy to include patients with AHL.