Dual Frequency Stimulation in Parkinson's Disease

Patients with idiopathic Parkinson's disease who have previously been implanted with the Boston Scientific VerciseTM DBS system for at least 3 months. These patients will already be receiving high-frequency dorsal STN stimulation as part of the standard of care for PD. Once patients have provided consent and are enrolled in this study, they will receive simultaneous low-frequency stimulation of the ventral STN to examine if there are any effects on cognitive performance.