At present, there is no cure for Parkinson's disease. The standard treatment involves taking dopaminergic drugs. When drugs lose their effectiveness, they can be supplemented by Deep Brain Stimulation (DBS) therapy. Medication and deep brain stimulation are effective for motor problems such as tremors, slowness of movement and muscle stiffness. However, there is no effective treatment for the walking and balance problems that occur during the course of the disease. DBS neurostimulators not only stimulate, but also record brain activity in the region in which the electrodes are implanted. This brain activity changes over time, depending on your general state (i.e., medication, eating), your movements (sitting, standing or walking) and your motor problems (i.e., problems of gait initiation and termination, balance problems and freezing of gait). Adaptive deep brain stimulation (aDBS) makes it possible to change the stimulation according to brain activity, and thus to these different states. This method involves using the usual Medtronic Percept neurostimulator by activating this adaptive function. In this study, we want to evaluate whether adaptive deep brain stimulation is safe and effective in improving walking problems in people with Parkinson's disease.