While several cholinesterase inhibitors have effectiveness in Alzheimer's disease (AD), galantamine is unique since it has a dual mode of action: inhibition of acetylcholinesterase and modulation of nicotinic acetylcholine receptors.As Parkinson's disease (PD) impacts frontal systems, executive cognition rather than memory function (mediated by medial temporal) would be the targeted area for potential improvement. This single center, double blind, placebo controlled study compares a group of PD patients treated with galantamine to a group of PD patients who are not treated with this medication on a series of cognitive tasks that examine attention and executive control.