The DBS STN is a non-curative treatment; its effect on the patient's quality of life (QoL) determines the therapeutic success of this procedure. We aimed to assess whether stimulation parameters setting may influence also some of the non-motor aspects of QoL. The QoL was assessed by PDQ-39 questionnaire. The questionnaire was administered to patients before and after the DBS surgery. A sham change of stimulation amplitude was performed before the actual increase. After the further amplitude increase in subgroup of patients (mean increase of amplitude of 0.35 V), there was a statistically significant additional improvement of total PDQ-39 score by another 22.9 %. In this group the emotions, stigma and communication subscales improved after the stimulation increase, without further change of UPDRS III. We were able to demonstrate that the increase of stimulation parameters (amplitude) has a potential to improve some non-motor functions and aspects of QoL and thus has an additional effect on quality of life in certain subset of PD patients. The meticulous observation of QoL should be a routine part of assessments before and after the DBS STN surgery, and can even aid during the parameter setting.