A cornerstone in PD research is the investigation of neurophysiological changes as potential biomarkers that could help in tracking disease progression and response to therapies. Electroencephalography (EEG) could provide a non-invasive and relatively cheap tool for identification of such biomarkers. In this study we will use high-density electroencephalograph (EEG) recording, in order to develop a platform of biomarkers that could be more sensitive and reliable to disease progression and response to therapeutic intervention than standard clinical measures.