Patient description: The patient is a 55-year-old man who was recently diagnosed with Parkinson's disease. He is complaining of slowness of movement and tremors. His disease is ranked as mild, Hoehn-Yahr Stage I. His past medical history is significant for hypertension and hypercholesterolemia. He lives with his wife. They have three children. He used to be active with gardening before his diagnosis. He complains of shaking and slow movement. He had difficulty entering through a door, as he was frozen and needed guidance to step in. His handwriting is getting smaller. He is offered Levodopa and Trihexyphenidyl. He is an alert and cooperative man who does not have any signs of dementia. He does not smoke or use any illicit drugs.

Clinical trial eligibility criteria: eligible ages (years): 40.0-85.0,  Lewy Body Dementia Have dementia as defined by a decline in cognitive function, which in the opinion of the investigator has resulted in functional impairment Meet diagnostic for PD per MDS or DLB per 4th Consensus Report of the DLB Consortium Have a score on the MoCA of 10 Are Modified Hoehn and Yahr Stages 0 Have a blood pressure (BP) or pulse rate at screening and randomization, as determined by three sequential BP/pulse rate measurements in a seated position Participants <60 years old: 1. A mean systolic BP less than or equal to 140 millimeters of mercury (mmHg), a mean diastolic BP less than or equal to 90 mmHg and a mean pulse rate less than or equal 90 beats/minute in a seated position. 2. Each of the 3 systolic BP measurement must be less than 180 mmHg Participants ≥60 years old: 1. A mean systolic BP less than or equal to 150 mmHg, a mean diastolic BP less than or equal to 90 mmHg and a mean pulse rate less than or equal to 90 beats/min in a seated position. 2. Each of the 3 systolic BP measurement must be less than 180 mmHg If on anti-parkinsonian agents, participants must be on stable dosage for at least 3 weeks prior to screening, and should remain on stable doses during the course of the study If on medications affecting cognition (rivastigmine, galantamine, donepezil, memantine), participants must be on stable dosage for at least 3 weeks prior to screening and should remain at a stable dosage during the course of the study If on antidepressant medications, participants must be on stable dosage for at least 3 weeks prior to screening and should remain at a stable dosage during the course of the study  Are women of childbearing potential Have significant central nervous system or psychiatric disease, other than PD or DLB, that in the investigator's opinion may affect cognition or the ability to complete the study Have a history in the last 6 months of transient ischemic attacks or ischemic stroke Have a history of intra cerebral hemorrhage due to hypertension Have a history of hypertensive encephalopathy Have atypical or secondary parkinsonism due to drugs (e.g., antipsychotics) or disease (such as progressive supranuclear palsy, essential tremor, multiple system atrophy (e.g. striatonigral degeneration, olivopontocerebellar atrophy), or postencephalitic parkinsonism) Have a current implantable intracranial stimulator or history of intracranial ablation surgery (e.g., subthalamic, globus pallidus-internal segment [GPi]) Have a history of substance abuse within the past 1 year (drug categories defined by the Diagnostic and Statistical Manual of Mental Disorder, 5th Edition [DSM-5], and/or substance dependence within the past 1 year, not including caffeine and nicotine Have a serious or unstable medical illness, other than idiopathic LBD (PDD or DLB), including cardiovascular, hepatic, respiratory, hematologic, endocrinologic, neurologic, or renal disease, or clinically significant laboratory or electrocardiogram (ECG) abnormality as determined by the investigator Have a history in the last 6 months of exertional angina, unstable angina, myocardial infarction, and acute coronary syndrome