Contralateral Hearing Status as a Determinant of Cochlear Implant Device Engagement and Rehabilitation Trajectory

OBJECTIVE: To compare device utilization, speech recognition trajectories, and predictive validity of early postactivation performance across 3 contralateral hearing status groups: single-sided deafness (SSD), asymmetric hearing loss (AHL), and bilateral nonserviceable hearing loss (BSHL). STUDY DESIGN: Retrospective longitudinal cohort study. SETTING: Tertiary academic medical center. METHODS: Retrospective review of 360 adult cochlear implant recipients implanted 2018 to 2024, classified by contralateral pure-tone average (PTA) into SSD (≤30 dB HL; n = 81), AHL (>30-50 dB HL; n = 41), and BSHL (>50 dB HL; n = 238). Measures included mean daily utilization via processor datalogging and Consonant-Nucleus-Consonant (CNC) word recognition at 1, 3, 6, and 12 months postactivation; distribution of utilization categories; multivariable predictors of limited use; and cross-temporal predictive validity. RESULTS: SSD showed lower utilization than BSHL through 6 months postactivation, with near-convergence by 12 months. Full-time utilization (≥8 h/day) was achieved by 50% of SSD patients compared to 82% of BSHL patients (P < .001). SSD was the sole independent predictor of limited use (OR = 4.38; 95% CI: 2.03-9.48; P < .001). CNC scores were persistently lower in SSD across the first postoperative year, failing to cross the 50% clinical responder threshold at 12 months. One-month postactivation performance strongly predicted 12-month outcomes in AHL and BSHL patients but not in SSD, indicating a fundamentally distinct early rehabilitation dynamic. CONCLUSION: Contralateral hearing status is an independent determinant of cochlear implant device engagement. SSD recipients demonstrate distinct utilization patterns, lower speech recognition trajectories, and unpredictable early rehabilitation dynamics, warranting configuration-specific counseling and heightened clinical surveillance beginning at the time of activation.