Parkinson's Disease (PD) affects movement and thinking. It can be hard to treat with just medicine or surgery. "OFF-time" is when medicine doesn't work well, and many people with PD experience this. Another issue is cognitive, or thinking, problems. This study looks at whether partnered dance aerobic exercise (PDAE) can help. PDAE combines dancing with aerobic exercise and requires being mentally active. This might help with movement and thinking issues in PD. The study will compare PDAE to walking over 16 months. Participants will do sessions twice a week for 3 months, then once a week for 13 months. Researchers will use brain scans to see if PDAE or walking protects brain cells. Participants must be over 40, able to walk at least 10 feet, and willing to be randomly assigned to a group. They should not have major psychiatric issues or certain heart conditions. During the study, they'll have exams and a brain scan to check progress. Researchers hope to find out if PDAE is better than walking for reducing "OFF-time" and improving thinking.

• Duration is 16 months, with weekly dance or walking sessions.
• Participants need to attend multiple check-ups and a brain scan.
• Participants will be randomly assigned to either dance or walking group.