Altered Resting-State Neural Oscillations and Functional Connectivity in Persistent Postural-Perceptual Dizziness

Background: Persistent postural-perceptual dizziness (PPPD) is a chronic functional neuro-otologic disorder marked by persistent dizziness, unsteadiness, and visual dependence. Its electrophysiological mechanisms remain unclear. This study examined resting-state EEG spectral power and functional connectivity in PPPD and their associations with postural stability and clinical symptoms. Methods: Forty patients with PPPD and 40 age- and sex-matched healthy controls were studied with an eyes-closed resting-state EEG recording. Static postural stability was measured with the Pro-Kin system. Spectral power was calculated for delta, theta, alpha, beta, and gamma bands. Functional connectivity was assessed using the weighted phase lag index. Results: Static posturography showed impaired postural stability in patients with PPPD compared with healthy controls. Spectral power analysis showed increased theta-band relative power over the frontal and left parieto–occipital regions. Connectivity analysis showed increased prefrontal–temporal and decreased temporal–occipital connectivity in the theta band, increased fronto–parieto–occipital and decreased parietal–temporal connectivity in the alpha band, and decreased cerebellar and temporal, central connectivity in the gamma band. Conclusions: PPPD was associated with frequency-specific alterations in resting-state cortical oscillations and functional connectivity involving cognitive–affective, visual, and sensorimotor networks. Resting-state EEG may help characterize network-level abnormalities in PPPD.