Resting-state electroencephalography of neural oscillation and functional connectivity patterns in late-life depression

Background: The clinical manifestations of late-life depression (LLD) are highly heterogeneous. Currently, abnormal characteristics of resting-state electroencephalography (EEG) power and functional connectivity are considered trait markers of depressive symptoms in major depression. However, the relationship between EEG spectral features and functional connectivity in LLD remains unknown. Methods: Forty-one patients with LLD and 44 participants without depression underwent an eyes-closed restingstate EEG. EEG power spectra, alpha asymmetry, and functional connectivity were calculated and analyzed.Results: Although alpha frontal asymmetry and cortical functional connectivity between the two groups showed no significant differences, the LLD group exhibited abnormal neural oscillation patterns of higher beta frequency activity in the parietal, central, and occipital lobes while alpha activity was increased in the parietal central electrodes. Limitations: The number of EEG electrodes used in this study was low, and the sample size was limited.Conclusions: Increased alpha and beta frequency band powers were observed in patients with LLD. These abnormal patterns may be associated with a disturbed balance of cortical excitation, inhibition, and hyperactivity. In the future, a neurofeedback protocol based on the findings of neural oscillation patterns in certain types of LLD should be explored.