Cortical Sources of Resting State Eeg Alpha Rhythms

Acknowledgments: This research was developed thank to the financial support by European Committee for the FP7-" ICT Infrastructure " project entitled " Diagnostic Enhancement of Confidence by an International Distributed Environment " (" DECIDE " , Grant Agreement: RI-261593) in the framework of the validation of spectral electroencephalographic indexes of disease progression in subjects with mild cognitive impairment. Therefore, this article is presented on behalf of the DECIDE Consortium. Please find complete information about the Consortium and principal investigators at www.eu-decide.eu. Abstract Cortical sources of resting state electroencephalographic (EEG) rhythms are abnormal in subjects with mild cognitive impairment (MCI). Here, we tested the hypothesis that these sources in amnesic MCI subjects further deteriorate over 1 year. To this aim, the resting state eyes-closed EEG data were recorded in 54 MCI subjects at baseline (Mini Mental State Evaluation, MMSE I= 26.9 ± 0.2 standard error, SE) and at approximately 1-year follow up (13.8 months ± 0.5 SE; MMSE II= 25.8 ± 0.2 SE). As a control, EEG recordings were also performed in 45 normal elderly (Nold) and in 50 mild AD subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-EEG sources were estimated by low-resolution brain electromagnetic tomography (LORETA). Compared to the Nold and mild AD subjects, the MCI subjects were characterized by an intermediate power of posterior alpha1 sources. In the MCI subjects, the follow-up EEG recordings showed a decreased power of posterior alpha1 and alpha2 sources. These results suggest that the resting state EEG alpha sources were sensitive-at least at group level-to the cognitive decline occurring in the amnesic MCI group over 1 year, and might represent cost-effective, non-invasive and widely available markers to follow amnesic MCI populations in large clinical trials.