Early neuropsychological outcome after carotid endarterectomy.

30 patients with a history of transient ischemic attacks (TIA) and 16 patients with cerebral infarcts were evaluated neuropsychologically 1-3 days before carotid endarterectomy, due to hemodynamically significant carotid artery stenosis, and again 2 weeks and 2 months after operation. Preoperatively, there were no differences between the groups, but postoperatively the neuropsychological outcome of the TIA patients was better than that of the infarction patients. Consequently, carotid endarterectomy patients cannot be studied as one group in neuropsychological examinations but various subgroups should be dealt with separately. In the TIA group 2 months after operation, the patients with left-sided operations had improved in verbal but not in visual tests, and the right-operated patients showed improvement also in visual tests. Therefore, the use of sum scores across neuropsychological tests is not preferable in the evaluation of the effects of carotid endarterectomy because after unilateral operation the cognitive improvement is greater in functions ipsilateral to the operation side.