BACKGROUND STN-DBS is well established to improve motor symptoms and quality of life in patients with PD. While non-motor symptoms are crucial for quality of life in these patients, only neuropsychiatric and neuropsychological symptoms have been systematically studied in a longitudinal design thus far. However, these are only a part of the spectrum of non-motor symptoms in PD. We hypothesized that STN-DBS is associated with a beneficial effect on a range of non-motor symptoms. METHODSIn this multicenter, open, prospective, international study we investigated non-motor effects of STN-DBS in "real-life" use. We evaluated Non-motor Symptom Scale, and Questionnaire, PD Questionnaire-8, Scales for Outcomes of PD motor examination and complications, and activities of daily living preoperatively and at 6 months follow-up in 60 consecutive patients (35 male, mean age: 61.64 ±7.84 years, mean disease duration: 10.45 ±4.22 years) undergoing STN-DBS. RESULTSAll outcomes improved significantly at 6 months follow-up (PD Questionaire-8, p=0.006; activities of daily living, p=0.012; all others, p<0.001; Wilcoxon signedrank, respectively paired t-test; Bonferroni-correction). Post-hoc analyses of Nonmotor Symptom Scale domains showed a significant reduction of sleep/fatigue and miscellaneous domains (p≤0.001), perceptual problems/hallucinations (p=0.036), and urinary (p=0.018) scores. Effect sizes were "moderate" effect for Non-motor Non-motor effects of subthalamic DBS -5 -Symptom Scale, and motor complications, "large" for motor examination, and "small" for other outcomes. CONCLUSIONSThis study provides first evidence that bilateral STN-DBS improves non-motor burden in patients with PD and opens the door to a more balanced evaluation of DBS outcomes. Further randomized studies are needed to confirm these findings and compare DBS non-motor effects to other therapies such as infusion based treatments of advanced PD.