Modeling Cognitive Trajectories in the Long-Term After Cochlear Implantation

BACKGROUND: Hearing restoration by cochlear implantation (CI) yields benefits beyond hearing. Short-term benefits on cognition are well-known, but long-term data are limited and inconsistent. Therefore, we analyzed a large sample of CI recipients with a focus on cognitive changes in the long-term follow-up. METHODS: Seventy-five CI recipients aged older than or equal to 50 (mean age 65.4, SD 9.2) were tested in attention, immediate and delayed recall, working memory (OSPAN) and verbal fluency (VF) pre-implantation and 12, 24, 54 as well as 99 months post-CI. Three linear mixed-effects models (linear, quadratic, and time-indicator) were fitted and contrasted. RESULTS: Despite different statistical assumptions, all 3 models converged on initial cognitive improvement after implantation. In the time-indicator model, significant improvements relative to baseline were observed across all 5 outcomes at 12 and 24 months (P