Decreased EEG phase synchronization in the elderly with mild cognitive impairment

The electroencephalography (EEG)-based phase synchronization in patients with mild cognitive impairment (MCI) was investigated in this study. Thirty elders from a community in Beijing, including 9 patients with MCI and 21 normal controls, participated in our experiment. We recorded their EEG when they were judging whether the color of two graphics was matched or not. The first 3 seconds EEG data after the stimulus onset were extracted and divided into 3 parts, i.e. 0-1s, 1-2s, 2-3s. Then phase synchronization index (PSI), γ value was used to evaluate their EEG synchronization. Results showed that, no significant difference between those of matching and mismatching was found; The γ values of the patients were lower than those of normal controls at the initial period of time 0-3s; Declining trend of phase synchronization network was found in both MCI and normal group, and MCI descended more quickly than normal group's. In spatial distribution, MCI and normal controls performed similar regularity and had common active areas in fronto-parietal and occipito-temporal regions.