Early tinnitus burden and subjective hearing are candidate markers of 2-year quality of life after cochlear implantation in single-sided deafness.

Background: Cochlear implantation is a common treatment for adults with single-sided deafness (SSD), but patient-reported benefits vary. The relationships among tinnitus burden, perceived hearing ability, psychological distress, disease-specific health-related quality of life, and whether early postoperative outcomes predict later results are not well understood. Objective: This study explores how disease-specific quality of life relates to tinnitus burden, hearing, stress, depression, and anxiety after cochlear implantation in SSD. It also seeks early markers linked to 2-year outcomes. Methods: This secondary complete-case analysis was based on a previously reported prospective longitudinal SSD cohort. Of 70 adults with postlingual SSD, 36 (51.4%) had complete Nijmegen Cochlear Implant Questionnaire (NCIQ) data at baseline and at 6 months, 1 year, and 2 years after unilateral cochlear implantation and were included. Additional measures included the Tinnitus Questionnaire (TQ), Oldenburg Inventory (OI), PerceivFed Stress Questionnaire (PSQ), General Depression Scale (ADS-L), Generalized Anxiety Disorder 7-item scale (GAD-7), and Freiburg Monosyllable Test (FMT) at 65 dB. Timepoint-specific correlations with the NCIQ were analyzed using Spearman's rank correlations. Exploratory multivariable analyses employed linear regression on rank-transformed variables to assess whether baseline and 6-month patient-reported profiles were associated with 2-year NCIQ outcomes. Longitudinal within-patient comparisons were conducted as a secondary descriptive analysis. Results: Higher NCIQ scores were linked to lower tinnitus burden and better hearing across all assessments. Associations with depression and anxiety persisted, while connections with perceived stress emerged after surgery. At baseline, higher tinnitus burden was associated with lower 2-year NCIQ scores. At 6 months, higher tinnitus is still associated with lower 2-year NCIQ scores, whereas better hearing is associated with higher 2-year NCIQ scores. Early postoperative improvement was followed by stabilization over 2 years. Conclusion: Improvement in health-related quality of life after cochlear implantation in adults with SSD is complex and extends beyond hearing alone. Tinnitus was the most consistent negative factor, while improved subjective hearing at 6 months was associated with better outcomes at 2 years. These results support a structured, multidimensional approach to patient-reported follow-up after cochlear implantation in SSD and suggest that early postoperative patient-reported status may serve as an early candidate marker for later quality-of-life outcomes.