Table 2 Study inclusion and exclusion criteria

 Age ≥65 years

Medical record

 Home location suitable for testing

Medical record

 German as a first language

Medical record or recruitment telephone call

 IADL score ≥6

Baseline assessment

 ASA physical status I–III

Baseline assessment

 Major elective surgery^a

Medical record

 Planned general anesthesia^a

Baseline assessment

 Cardiac surgery^a

Medical record

 Neurosurgery including carotid endarterectomy, or any type of surgery precluding postoperative testing^a

Medical record

 (Another) major surgery within the study timeline

Medical record, recruitment telephone call or baseline interview

 General anesthesia up to 3 months prior to inclusion

Medical record

 Baseline MMSE score <24

Baseline neuropsychological assessment

 Dementia criteria per DSM-5

Baseline neuropsychological assessment

 Previous pathological cerebral imaging (if available)

Medical record

 History of cerebral or cerebrovascular pathology, head trauma, neurodegenerative illness or epilepsy

Medical record

 Chronic use of psychiatric medication

Medical record or baseline interview

 Alcohol or substance abuse

Medical record or baseline interview

 History of chronic pain unrelated to the planned surgery

Medical record

 Chronic medical illness known to induce encephalopathy

Medical record

 Any contraindication for MRI (e.g., pacemakers and other MRI-incompatible implantable device)

Medical record, recruitment telephone call or baseline interview

 Claustrophobia

Medical record, recruitment telephone call or baseline interview

 Incidentally diagnosed disease or unfavorable course of disease in participants who choose not to be informed

Any study assessment

 Lack of informed consent

Recruitment telephone call