Retrospective Evaluation of POCD Data of Studies From KAI, Charité - Universitätsmedizin Berlin

Study Group Inclusion Criteria: * Age 18 -100 years * Male or female patients undergoing elective surgery expected to last at least 60 min, screened at the Department of Anesthesiology and Operative Intensive Care Medicine (CCM, CVK), Charité - Universitätsmedizin Berlin, Berlin, Germany * Written informed consent to participate after having been properly instructed Exclusion Criteria: * Lacking willingness to take part in the study, or to have relevant study data collected, saved and analyzed for the purpose of the study * Accommodation in an institution due to an official or judicial order * Insufficient knowledge of German language * Members of the hospital staff * Homelessness or other conditions that disable reachability for postoperative assessment by post or telephone * Illiteracy * Patients who had a history of neurologic deficits (e.g. stroke, history of seizures, etc.) * Hearing impairment that severely affects the neuropsychological testing. * Visual impairment that severely affects the neuropsychological testing. * Participation in other prospective clinical interventional trials Control Group Inclusion Criteria: * Age 18 - 100 years * Male or female patients (ASA Status I, II+III) * No planned surgery during the next 3 months * No surgery during the past 6 months before study inclusion * Written informed consent to participate after having been properly instructed Exclusion Criteria: * Insufficient knowledge of German language Lacking willingness to take part in the study, or to have relevant study data collected, saved and analyzed for the purpose of the study * Neuropsychiatric conditions that severely affect the neuropsychological testing * Hearing impairment that severely affects the neuropsychological testing * Visual impairment that severely affects the neuropsychological testing