Factors That Influence Second-side Cochlear Implant Speech Recognition Outcomes

Objective: Assess relationships between patient, hearing, and cochlear implant (CI)-related factors and second-side CI speech recognition outcomes in adults who are bilaterally implanted. Study Design: Retrospective review of a prospectively maintained CI database. Setting: Tertiary academic center. Patients: One hundred two adults receiving bilateral sequential or simultaneous CIs. Outcome Measures: Postimplantation consonant-nucleus-consonant (CNC) word and AzBio sentence scores at >= 12 months. Results: Of patient, hearing and CI-specific, factors examined only postimplantation speech recognition scores of the first CI were independently associated with speech recognition performance of the second CI on multivariable regression analysis (CNC: ss = 0.471[0.298, 0.644]; AzBio: ss = 0.602[0.417, 0.769]). First-side postoperative CNC scores explained 24.3% of variation in second CI postoperative CNC scores, while change in first CI AzBio scores explained 40.3% of variation in second CI AzBio scores. Based on established 95% confidence intervals, 75.2% (CNC) and 65.9% (AzBio) of patients score equivalent or better with their second CI compared to first CI performance. Age at implantation, duration of hearing loss, receiving simultaneous versus sequential CIs, and preoperative residual hearing (measured by pure-tone average and aided speech recognition scores) were not associated with 12 month speech recognition scores at 12 months. Conclusions: The degree of improvement in speech recognition from first CI may predict speech recognition with a second CI. This provides preliminary evidence-based expectations for patients considering a second CI. Counseling should be guarded given the remaining unexplained variability in outcomes. Nonetheless, these data may assist decision making when considering a second CI versus continued use of a hearing aid for an unimplanted ear.