**Gait Analysis in Neurological Disease Study** This study will explore how people with certain neurological conditions, like Parkinson's Disease, walk differently compared to healthy people. *Gait* means how someone walks. Researchers will compare 40 people with Parkinson's and 40 healthy people as they walk on a special path with pressure sensors. These sensors measure walking patterns at different speeds. The study will also look at different walking patterns in people with other conditions like ataxia, which affects balance and movement. Key Points to Consider: - **Study Duration and Visits:** Participants will walk nine trials. There is an optional second visit where some participants may walk without their Parkinson's medication or devices. - **Eligibility:** Participants should be between ages 18-85. Those with Parkinson's must have certain symptoms like slow movement or tremors, and healthy participants should have no walking issues. - **Risks and Participation:** Only people who can safely walk and are not part of another study can join. Participants may use their assistive devices if needed. This study helps understand how diseases like Parkinson's change walking patterns, which may help improve treatments in the future.