The aim of the study is to determine whether galantamine stabilizes or improves thinking abilities in individuals with Parkinson's disease. Individuals included in the study have minor complaints about thinking such as problems with concentration or memory but do not have dementia. This medication has been shown to have a positive effect on stabilizing memory in individuals with Alzheimer's disease. It is FDA approved for use in elderly individuals with Alzheimer's disease. It is hypothesized that galantamine will stabilize or improve executive and attentional functions in individuals with Parkinson's.