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

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).

Retrospective longitudinal cohort study.

Tertiary academic medical center.

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.

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.

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.