Subthalamic nucleus (STN) deep brain stimulation (DBS) is well established for the symptomatic treatment of Parkinson's disease (PD) improving motor symptoms, activities of daily living (ADL), and quality of life (QoL) [1–3]. Non-motor symptoms (NMS) play a crucial role for QoL in patients with PD [4,5]. Long-term effects of DBS on neuropsychological [6,7] and neuropsychiatric symptoms [8,9] have been studied. However, these symptoms contribute only to a part of NMS in patients with PD. Previously published studies on a wider range of NMS have methodological limitations due to a lack of objective clinician-based , patient-based [11,12] or any validated assessment at all , and small cohort sizes of only 10 [13,14] or 11 subjects followed up on 6 month .