All patients will undergo surgery as planned. On the day of surgery, prior to proceeding to the operating room, patients will be assessed with the Confusion Assessment Method (CAM) to confirm no presence of delirium pre-operatively. In the Post-anesthesia Recovery Unit, a different member of the research team (blinded to the patient's group assignment) will repeat the CAM to assess for PD. While hospitalized, pain scores determined using the Verbal Analog Scale and narcotic use will be obtained from the electronic medical record with at least 8 hour frequency (entered by registered nurses). All participants will be evaluated by a blinded researcher using the combined CAM/Memorial Delirium Assessment Scale (MDAS) at 7:30AM ± 1.5 hrs and 6:30PM ± 1.5 hrs for PD on subsequent post-op days until discharge. Additionally, the PQRS will be completed at each 6:30PM ± 1.5 hrs assessment. The PQRS, MMSE, and SAGE will be repeated just prior to discharge or on POD 7. A different form for the SAGE examination, as well as alternate number and word sequences for the PQRS and MMSE assessments, will be used in order to reduce the potential influence of the learning effect. At the end of this visit, active patient participation is complete. For subjects discharged before POD 7, the PQRS will be given again via telephone. Follow-up visits will be conducted on POD 30 and POD 90 via telephone. The PQRS will be obtained on POD 30, and the PQRS, GDS, and SF-36 will be obtained on POD 90. The research team will also periodically check the medical record during this time for readmissions and provider notes related to medical events. Participation is complete after POD 90.