Motor, cognitive and psychological assessment. Patients will perform a short motor, cognitive and psychological assessment using the UPDRS III, the MMSE and VASs for subjective evaluation of mood, anxiety, movement difficulty and motor fatigue. VASs will be performed twice: in STN DBS ON and OFF conditions for experimental group, and in the first and the second session for the control group. UPDRS III and MMSE will be evaluated when patients from the experimental group are in STN DBS ON condition and when control patients are in the first session.