Comparison of resting eeg findings between amnesic mild cognitive impairmentand alzheimer disease

Objective: In the current study, differences in resting state EEG between Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) were investigated. Method: Twenty aMCI patients, 20 AD patients and 20 demographically-matched healthy controls (HC) were participated. EEG data was recorded for 4 minutes of eyes-closed condition according to the international 10-20 system. EEG rhythms of interest were delta (0.5-3.9 Hz), theta (4–7.8 Hz), alpha1 (8–10.4 Hz), alpha2 (10.5–13 Hz), beta1 (13–20 Hz), and beta2 (20–30 Hz). Sensitivity and specificity values were assessed using ROC analysis to distinguish AD from aMCI and HC. Results: Repeated measures of ANOVA revealed main Group effects on delta [F(2,57) = 8.353; p=0.001], theta [F(2,57)=5.038; p=0.010], alpha [F(2,57)=3.837; p=0.027], and alpha1 [F(2,57)=4.209; p=0.020] power between groups. Interaction effects of Anterior-Posterior Electrode Location x Group on delta [F(6,171)=2.621; p=0,038], and theta [F(6,171)=3.537; p=0.020] power were observed, indicating in comparison to HC and aMCI group, AD patients showed decreased delta power in frontal, central and parietal electrode locations (for all; p<0.040). AD patients also had decreased alpha and alpha1 power compared to HC (for all; p<0.026). Moreover, when using the cut-off score of >1.71 to identify AD from aMCI on central electrodes, and >1.73 to identify AD from HC on parietal electrodes yielded a sensitivity of 80.0% and a specificity of 80.0% for each. Moreover, several correlations were found between cognitive domains and resting state EEG rhythms. Conclusion: Compared to healthy controls and aMCI group, AD patients was characterized by increased delta and theta power and compared to healthy controls AD patients was characterized by decreased alpha power. Our findings indicate importance of delta EEG power as a neurophysiological marker in distinguishing AD from aMCI and from HC. Keywords: Alzheimer's disease, Mild cognitive impairment, Resting state EEG, delta, teta