Cognition after major surgery in the elderly: test performance and complaints

There is evidence that older people in particular have a higher risk of cognitive dysfunctionafter surgery under general anaesthesia. We have investigated the severity and character ofpostoperative cognitive dysfunction after major non-cardiac surgery in patients older than65 yr. Also, cognitive complaints were studied. Cognitive function was assessed using cognitivetests measuring memory and attention, such as ability to shift between two sequences, abilityto ward off distractions, simple cognitive speed and speed of general information processing.These tests were performed before, 1 week (short-term) and 3 months (long-term) aftersurgery. Cognitive performance of the patients was compared with that of healthy subjectsnot undergoing surgery who were also subjected to repeated cognitive measurements. After1 week, patients had a poorer performance on tests measuring simple cognitive speed andspeed of general information processing. Three months after surgery, patients and controlsshowed improved cognitive performance compared with the first measurement. These resultssuggest that major non-cardiac surgery in older patients causes short-term but not long-termcognitive dysfunction. However, after 6 months, 14 of 48 patients (29%) reported havingexperienced a decline in cognitive abilities after discharge from hospital. Eight of these 14patients (17%) were still experiencing these cognitive complaints and reported ‘not being thesame since the operation’. These findings emphasize that cognitive complaints after majorsurgery may not reflect actual changes in cognitive performance but may be caused by otherfactors such as depression or awareness of age-related changes