Identifying brain activity that predicts postoperative delirium in older adults undergoing anaesthesia and surgery

This observational study is primarily aimed at observing the incidence of postoperative delirium and correlating this with changes in the multichannel EEG. The population of patients are those already scheduled for anaesthesia and surgery. Most assessments (excluding a pre admission and 3 month follow up cognition assessment by phone) will occur during the subjects usual hospital stay. The multichannel EEG will be recorded at multiple timepoints - preoperative, intraoperative (induction, maintenance, emergence), and the postoperative anaesthetic care unit (PACU) Postoperative delirium assessments will occur preoperatively and twice daily until day 3 postoperatively As a secondary outcome, blood based biomarkers (neural injury and inflammatory) will be obtained at baseline and postoperative day 1 and 2. Cognition assessments will also be performed prior to admission and at 3 month follow up. Participant time commitment likely to be: Pre-admission cognition assessment (telephone) - 30minutes Fitting of EEG recording equipment prior to surgery - 20 minutes Postoperative delirium assessments - 2 to 10 minutes for each assessment (twice daily until postoperative day 3) Final 3 month follow up cognition assessment (telephone) - 30 minutes