This study explores how **vagal nerve stimulation** might help people with **Parkinson's disease (PD)**. Parkinson’s disease is a condition that affects movement, causing stiffness and balance problems. The **vagus nerve** is a nerve in the neck that can be stimulated to potentially improve muscle function and balance. The study will check if stimulating this nerve can improve muscle activity and help with walking and staying upright. **Key Points**: - **Participation Length**: Involves multiple visits over a period of time. - **Eligibility**: Must have Parkinson's, be on stable medication, and able to walk 50 meters without help. - **Compensation**: Participants may receive compensation for their time and effort. People with severe heart problems, recent substance abuse, or certain medical devices can't join. If this study works, it could lead to better treatments for muscle and balance issues in PD.