Baseline Differences in Cochlear Implant Candidates: Bilateral Traditional vs. Expanded Indications

Background/Objectives: Cochlear implant (CI) candidacy has expanded beyond traditional bilateral hearing loss (HL) to include single-sided deafness (SSD) and asymmetric hearing loss (AHL), yet baseline differences in speech recognition and patient-reported outcome measures (PROMs) between these groups-bilateral HL, SSD, and AHL-remain poorly characterized. The objective of this study was to characterize and compare preoperative speech recognition performance and PROMs between traditional bilateral HL and SSD/AHL CI candidates, and to examine associations between preoperative word recognition scores and PROMs across the full cohort. Methods: Sixty-eight adults (mean age 71.6 years, SD 7.4) undergoing preoperative CI evaluation were enrolled (31 bilateral HL, 12 SSD, and 25 AHL). Consonant-Nucleus-Consonant (CNC) word recognition and AzBio sentence recognition were assessed for both the ear-to-be-implanted (CI ear) and the contralateral ear. The following PROMs were evaluated: the Speech, Spatial and Qualities of Hearing Scale (SSQ-12); Cochlear Implant Quality of Life-35 (CIQOL-35); Patient Health Questionnaire-2 (PHQ-2); Tinnitus Handicap Inventory (THI); and the Instrumental Activities of Daily Living (IADL). Group comparisons used Mann-Whitney U tests and t-tests. CNC, SSQ-Mean, and CIQOL-Global associations were assessed using multivariable linear regression analysis. Results: Preoperative CI-ear speech recognition did not differ between the bilateral HL and SSD/AHL groups. SSD/AHL candidates had significantly higher contralateral-ear speech recognition performance, better SSQ-12 scores across all domains, and higher CIQOL-35 Global, Communication, Entertainment, and Environment scores compared to bilateral HL candidates. However, the CIQOL-35 Emotional, Listening Effort, and Social domains, PHQ-2, THI, and IADL did not differ significantly between the bilateral HL and SSD/AHL groups. Across our entire sample of candidates, CI-ear CNC scores were not significantly associated with preoperative SSQ-Mean or CIQOL-Global scores, while contralateral-ear CNC scores showed moderate, significant associations with both measures. Conclusions: Traditional bilateral and SSD/AHL CI candidates exhibit distinct preoperative PROM profiles (namely, the SSQ-12 and CIQOL-35) despite having no significant differences in CI-ear speech recognition. Contralateral-ear CNC scores-but not CI-ear scores-were significantly associated with the SSQ-Mean and CIQOL-Global, suggesting that contralateral-ear CNC scores may offer relevant insight into CI candidates' functional hearing. These findings support population-specific counseling and highlight the complementary value of PROMs and audiometric data in CI candidacy evaluations.