In this study, researchers are exploring ways to help people with Parkinson's disease (PD) who experience "freezing of gait" (FoG). FoG is when someone's walking suddenly stops, causing balance issues and falls. This study focuses on patients who have had a treatment called **STN-DBS** (deep brain stimulation) but still experience FoG. Researchers want to see if adjusting the **STN-DBS** intensity or increasing **levodopa** (a medicine that helps with PD symptoms) can improve walking.

Participants will have their walking recorded using sensors on their feet and back. They'll do different walking tasks, and testers will check their movement and thinking skills. The study uses a "cross-over" method, meaning participants try both treatments to see which helps more.

• Study Duration: Participants will be involved in the study for the duration of the evaluations and treatments.
• Eligibility: Participants must have good control of other PD symptoms but still experience FoG.
• Risks: There may be side effects from higher doses of levodopa or increased DBS intensity.