This study is researching Parkinson's disease (a condition that affects movement) by using special devices to measure eye and hand movements. It's exploring if these measurements can help understand and predict the disease better. **Parkinson's Disease** is a brain disorder that leads to shaking, stiffness, and difficulty with walking, balance, and coordination.

The study involves using devices like the **ANLIVA® Hand Movement** and **ANLIVA® Eye Movement** tools, which are non-invasive, meaning they don't involve surgery or entering the body. Participants will have their data captured by a clinical investigator and may complete questionnaires. Some participants will be part of a special **OFF/ON study** where they won't take their usual medications before certain tests.

Participants may have to visit the clinic up to four times over 18 months. The study includes people with Parkinson's, Essential Tremor (a shaking disorder), and healthy controls for comparison. To be part of the study, participants need to be over 18, able to understand and sign forms, and not have other movement disorders or conditions affecting the study.

• Study visits may include four clinic visits over 18 months.
• Some participants won't take their medication before testing.
• Participants will use non-invasive devices for measuring movements.