Combined Stimulation of STN and SNr for Dysphagia in Parkinson's Disease

20 patients with idiopathic Parkinson's disease and dysphagia will be included into this randomised controlled double-blinded parallel group clinical trial. The treatment consists of two different stimulation settings using (i) conventional stimulation of the subthalamic nucleus \[standard STN\] as active comparator and (ii) combined stimulation of active electrode contacts located in both the subthalamic nucleus and substantia nigra pars reticulata \[STN+SNr\]. Both groups receive additional swallowing therapy as standard of care.