The Change of Resting EEG in Depressive Disorders

Recent research suggested that the resting EEG could provide a biomarker for the depressive disorders and an objective index for the respond effect to treatment. To provide further evidence of the relationship of EEG signal and depression, we reported a pilot result based on the resting EEG. By recording the resting EEG signals in the three groups of normal control, unmedicated depressed patients and medicated depressed patients, after the analysis of fast fourier transform (FFT) to change time base signal into frequency information, we found that signals in many frequency bands of brain waves were related to the value of Beck Depression Inventory (BDI), especially in the Beta frequency band and in the frontal area in the unmedicated depressed group. Furthermore, we also found that comparing to the normal controls, the unmedicated depressed patients showed a stronger asymmetry in many frequency bands both in the frontal and parietal regions, which meant that the EEG signals were weaker in the left brain than in the right in the unmedicated depressed group.