Functional cortical source connectivity of resting state electroencephalographic alpha rhythms shows similar abnormalities in patients with mild cognitive impairment due to Alzheimer's and Parkinson's diseases
Objective: This study tested the hypothesis that markers of functional cortical source connectivity of resting
state eyes-closed electroencephalographic (rsEEG) rhythms may be abnormal in subjects with mild
cognitive impairment due to Alzheimer’s (ADMCI) and Parkinson’s (PDMCI) diseases compared to healthy
elderly subjects (Nold).
Methods: rsEEG data had been collected in ADMCI, PDMCI, and Nold subjects (N = 75 for any group).
eLORETA freeware estimated functional lagged linear connectivity (LLC) from rsEEG cortical sources.
Area under receiver operating characteristic (AUROC) curve indexed the accuracy in the classification
of Nold and MCI individuals.
Results: Posterior interhemispheric and widespread intrahemispheric alpha LLC solutions were abnormally
lower in both MCI groups compared to the Nold group. At the individual level, AUROC curves of
LLC solutions in posterior alpha sources exhibited moderate accuracies (0.70–0.72) in the discrimination
of Nold vs. ADMCI-PDMCI individuals. No differences in the LLC solutions were found between the two
MCI groups.
Conclusions: These findings unveil similar abnormalities in functional cortical connectivity estimated in
widespread alpha sources in ADMCI and PDMCI. This was true at both group and individual levels.
Significance: The similar abnormality of alpha source connectivity in ADMCI and PDMCI subjects might
reflect common cholinergic impairment