Parkinson’s disease dementia (PDD) is a complication in the course of Parkinson’s disease (PD). The pathophysiological process, however, is not completely understood, and it is of high practical importance to develop new methods for detecting the cognitive decline in PD in a very early state. Recent studies have shown that quantitative EEG (QEEG) measurements are among the most promising methods to predict and monitor cognitive decline. While QEEG is not affected by repetitive examination artifacts, limitations include that the conventional analysis by power spectra doesn't reflect sufficiently the complexity of the underlying neurophysiological process. Therefore, we aim to establish an analytical AI-based tool operating on entropy and synchrony measures to capture more of the complex mechanisms underlying cognitive decline in some patients with PD.