Event-related oscillatory responses reflect the cognitive status in many neuropsychiatric conditions including mild cognitive impairment (MCI). In this study, a total of 30 patients with amnestic MCI (aMCI) and 25 patients with MCI of Parkinson's disease (PD-MCI) were compared with 28 aged-, gender-, education-matched healthy control (HC) participants using visual event-related delta, theta, alpha oscillatory responses by methods of event-related spectral perturbation and inter-trial coherence. PD-MCI and aMCI groups commonly share a decreased theta power, but all electrophysiological deviations from the controls were more prominent in PD-MCI than aMCI in all frequency bands. Additionally, decreased phase-locking in all studied frequency bands was encountered only in PD-MCI group, but it was preserved in aMCI. These findings indicate that visual networks in PD-MCI are more severely affected than aMCI. Reduced phase-locking in PD-MCI may possibly relate to dysfunctioning subcortical modulating centers that take a role in the generation of event-related responses.
Keywords: Alzheimer; Event-related; Mild cognitive impairment; Oscillation; Parkinson; Phase-locking; Power; Theta.
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