Effect of different durations of preoperative computerised cognitive training on postoperative delirium in older patients undergoing cardiac surgery: a study protocol for a prospective, randomised controlled trial.

Introduction: Postoperative delirium (POD) is a common neurological complication after surgery among older patients, characterised by acute disturbances in consciousness, attention and cognition, usually occurring within 24-72 hours after surgery. POD has a significant impact on the prognosis of older patients undergoing major cardiovascular surgery, including increased length of hospital stay, hospital costs and readmission rates, with an incidence rate as high as 26%-52%. Computerised cognitive training (CCT) refers to difficulty-adaptive training in cognitive domains such as attention, memory and logical reasoning, using systematically designed tasks.