Effects of Vagal Nerve Stimulation on Leg Muscle Activity and Posture in Parkinson's Disease

This study tests whether a gentle, non-invasive form of nerve stimulation (applied to the neck) can improve muscle activity and posture in people with Parkinson's disease. The device stimulates the vagus nerve through the skin without surgery. **You may be eligible if...** - You have been diagnosed with Parkinson's disease - Your medications have been stable for the past month and are expected to remain stable for 3 months - You can walk at least 50 meters without a walking aid - (For control group) You are similar in age and sex to Parkinson's participants **You may NOT be eligible if...** - You have another significant neurological condition besides Parkinson's - You have had a stroke, brain injury, aneurysm, or brain tumor - You have a serious bone or joint problem affecting your walking - You are pregnant or may be pregnant - You have neck pain, lesions, or previous neck surgery at the stimulation site - You have had a substance use problem in the past 2 years Talk to your doctor to see if this trial is right for you.