EEG microstates and dynamic functional connectivity reveal stage-specific brain networks in subjective tinnitus.

Tinnitus with normal hearing suggests central mechanisms, yet stage-specific brain network dynamics remain unclear. This study investigated stage-specific brain network patterns in normal-hearing tinnitus patients using electroencephalography (EEG) microstate and dynamic functional network (DFN) analyses. Resting-state EEG was recorded from 45 participants (15 acute tinnitus, <6 months; 15 chronic tinnitus, ≥6 months; and 15 healthy controls). Results showed that acute tinnitus involved enhanced salience network engagement and reduced central executive network participation, with transitions skewed toward salience processing. Chronic tinnitus exhibited normalized transitions but increased global explained variance, indicating greater network stability. DFN analysis revealed elevated γ-band efficiency in the executive network during acute tinnitus, while chronic tinnitus showed increased low-frequency (δ/β) efficiency in executive and auditory networks. These findings demonstrate distinct neurophysiological profiles across tinnitus stages-acute salience-executive imbalance with aberrant high-frequency synchrony versus chronic compensatory rebalancing through low-frequency adaptation-providing a framework for stage-specific biomarker identification.