RecruitingPhase 2Drug trialReducing Falls With Varenicline in Hypocholinergic Parkinson DiseaseThis trial aims to test whether one year of Varenicline, when compared to placebo, can reduce fall risk and show improvement in the ability to multitask while walking. Participants that are eligible after screening for the study will be randomized to receive Varenicline or placebo. Along with the study medication participants will have visits (over the phone and in person), various tests and imaging, questionnaires, and laboratory collections.