Parkinson's disease is a brain disorder that affects movement and other body functions. In this study, researchers are using ultrasonography (a type of medical imaging using sound waves) to measure the thickness of certain abdominal accessory respiratory muscles (like the rectus abdominis) in people with Parkinson's. They want to see if there's a link between how severe the disease is and the strength of the muscles used for exhaling (breathing out). The study will involve people with Parkinson's at different stages, and they will undergo tests to measure their respiratory muscle strength and disease severity. These findings might help in creating exercise programs to support breathing in later stages of Parkinson's.

• Participants must be 18 or older with a certain stage of Parkinson's and a specific mental state score.
• People who smoke, have chest diseases, or unstable health conditions cannot join.
• The study does not involve any new treatment or medication.