Effects of Transcranial Focused Ultrasound Stimulation (tFUS) on Neurological and Cognitive Outcomes in Parkinson's Disease

This study is testing transcranial ultrasound stimulation (TUS) — a non-invasive brain stimulation technique that uses focused sound waves — to see if it can improve thinking, memory, and neurological function in people with Alzheimer's disease, Parkinson's disease, or mild cognitive impairment. **You may be eligible if...** - You are 18–80 years old - You have been clinically diagnosed with Alzheimer's disease, Parkinson's disease, Parkinson's dementia, or mild cognitive impairment - You can read and understand English - You have normal or corrected-to-normal vision and hearing - You are medically stable as assessed by the research team **You may NOT be eligible if...** - You have implanted metal devices or a pacemaker that are incompatible with the TUS or MRI technology - You have uncontrolled heart conditions or a history of recent heart attack - You have a significant unrelated neurological disorder (beyond the target disease) - You have a psychiatric diagnosis such as OCD, psychosis, or bipolar disorder - You have a history of epilepsy or multiple seizures - You have had recent brain surgery or significant brain injury - You have used recreational drugs within the past month Talk to your doctor to see if this trial is right for you.