Dynamic functional connectivity following cochlear implantation: Predicting speech outcomes and exploring brain network dynamics

Abstract

Cochlear implants (CIs) have transformed hearing restoration for individuals with severe or profound hearing loss, yet outcomes vary widely and remain difficult to predict. This study introduces an approach by examining the temporal dynamics of brain functional networks postimplantation to identify predictors of outcomes and explore brain plasticity. Twenty-nine CI candidates and 23 normal-hearing individuals participated. Functional near-infrared spectroscopy measured brain activity during audio-only and visual-only speech tasks at 1 mo and 1 y postimplantation, with speech understanding assessed after 1 y. Brain community dynamics were analyzed using multilayer modularity and network switching rates to capture temporal reorganization. Lower network switching rates shortly after implantation were associated with better long-term speech performance. Evidence of cross-modal plasticity—reflecting preimplant neural reorganization—was observed in early recordings, indicated by increased module allegiance between the posterior temporal (PT) region and visual cortices, which diminished after 1 y. Additionally, interhemispheric connectivity in the PT showed significant improvement between sessions, reducing disparities between CI users and normal-hearing individuals. These findings highlight dynamic functional connectivity as a meaningful neural correlate of outcome variability, with potential relevance for guiding personalized rehabilitation strategies and optimizing auditory and speech outcomes.