Postoperative Cognitive Dysfunction in Elderly

Interventional Study of Early Postoperative Cognitive Dysfunction in Elderly Patients Undergoing General Anesthesia The main purpose of this study is to determine the incidence of early postoperative cognitive dysfunction in elderly patients and its time course. This study will first evaluate the preoperative cognitive function of elderly patients based on several criteria including complete patient history, laboratory and instrumental exams, and the following measures in order to identify conditions and pathologies that may influence cognitive function. * Mini Mental State Examination * Geriatric Index of Comorbidity * Geriatric Depression Scale The following neuropsychological tests will be performed on the same day within 7 days of surgery (baseline): * Trail Making Test B-A * Digit Span * Digit Symbol Substitution Test The three cognitive function assessments will be repeated at the following postoperative time points and the change from the preoperative baseline to each time will be evaluated: * Day 2 (time point 1) * Day 4 (time point 2) * Between days 85 and 90 (time point 3) If the patient seems confused before the postoperative administration of these tests, the Neecham Confusion Scale will be used to evaluate the patient for the presence of postoperative delirium; if delirium is not detected, the cognitive function tests will be administered.