Dysfunctional brain dynamics in Subjects with major depression: An EEG microstate spectral analysis

Major depressive disorder (MDD) which is a widespread disorder worldwide cause disruption in some brain functions and thus leads to brain network changes. An increasing number of clinical and cognitive neuroscience studies have used broadband EEG microstate method to assess the electrical activity of large-scale cortical networks; however, the topographic frequency patterns of the different EEG microstate categories in MDD patients are not clear. In this study, EEG microstate frequency spectra were analyzed using 5-min resting-state electroencephalography (EEG) data from 55 subjects (including 27 MDD patients and 28 healthy controls) with variational empirical mode decomposition in Hilbert-Huang transform. The results showed that microstate D and the other microstates (A, C, and E) display opposite patterns. Most specifically, in the beta band, the marginal spectral energies of microstates A, C, and E were increased in MDD patients compared to HCs, while the energy of microstate D was decreased. Meanwhile, we observed that the marginal spectral energies of microstates A and C in the beta band were positively correlated with the severity of depressive symptoms, suggesting that alterations in the beta band energy can serve as an important reference for disease progression. These results confirm the abnormalities of beta-band energy in MDD patient and provide a new perspective for exploring the abnormalities of psychomotor function in patients with MDD.