Application of a newly developed semiquantitative questionnaire (FST-questionnaire [Fragebogen zur Veränderung der Selbstwahrnehmung unter tiefer Hirnstimulation]: Questionnaire regarding changes in self-perception while treated with DBS) to systematically assess changes in self-perception in a single-center, cross-sectional pilot-study at the University Hospital Freiburg, Germany on 50 patients (44% male; age 50 years [range: 27-73 years]), undergoing neurostimulation (DBS, iVNS, tVNS, or eTNS) to treat Parkinson's disease or epilepsy.