Age-related changes of EEG and its source in resting state

This study aimed to investigate the age-related changes in resting-state electroencephalogram (EEG) and EEG source, using spectrum analysis and wavelet entropy (WE). The data were collected from 9 healthy older adults and 16 young adults, with 128-channel NeuroSCAN EEG System. All the subjects were asked to close their eyes for 10 minutes. After preprocessing, the EEG power in different frequency bands and WE were calculated and analyzed. In order to localize the EEG in the cortex, we explored the source of EEG under the minimum norm-based constraint. Finally, we compute the power in alpha-band, beta-band, gamma-band, and WE of the signals in the source space. The result of power analysis showed that when compared to young subjects, the older adults had significantly reduced alpha activity in bilateral temporal pole areas and right parieto-tempora-occipital areas, while they had increased beta and gamma wave when resting. Source analysis showed the possible brain regions that generated these age-related changes. Finally, analysis on entropy showed increased brain wavelet complexity in older adults, and the generating sources were occipito-parietal lobes. It is possible that the older adults have more ongoing brain activities even at resting state, which could possibly be related to the dysfunction in inhibition. Future study is needed to confirm this assumption.