In this work, we analyzed dynamic functional connectivity in 56 subjects (25 healthy controls and 31 MCI-LB) in order to detect changes related to early signs of neurodegeneration in the fMRI in brain states related to preparation to the action. We used method called sliding window analysis. We found significant differences in dwell time in one of 4 identified brain states. This dwell time significantly correlated with visuospatial memory in MCI-LB group whereas in HC group was no significant correlation present. Observed changes probably reflect compensatory mechanisms of MCI-LB.