['To assess changes in cognitive function and affective state following carotid endarterectomy (CEA) for high-degree unilateral internal carotid artery stenosis.', 'In 33 patients, a CEA was performed under local anaesthesia for a high-grade unilateral stenosis of the internal carotid artery (group A). Twenty-five patients underwent surgery for peripheral arterial occlusive disease under regional anaesthesia served as controls (group B). Patients with neurological deficits due to previous strokes or dementia were excluded. Intelligence level was assessed preoperatively. Cognitive tests were applied preoperatively and postoperatively (3-5 days after surgery) and after 4 months follow-up. Confounding factors, including anxiety and depression, were checked through questionnaires and interviews.', 'No perioperative neurological complication occurred following CEA. Patients in group A showed a significant postoperative deterioration only in one sub-test. There was no significant change in anxiety and depression during follow up. The control group B had no significant changes in cognitive test performance. Anxiety improved significantly postoperatively, but increased again at the end of the study. There was no significant difference between the groups over time.'] Does cognitive function remain unchanged after endarterectomy of unilateral internal carotid artery stenosis under local anaesthesia?