Neuropsychological improvement versus practice effect following unilateral carotid endarterectomy in patients without stroke

Patients who were admitted to hospital for a recent transient ischemic attack were entered into one of three groups based on medical and surgical characteristics; those with an abnormal neurological examination or a focal abnormality on CT Scan were omitted from the study. The two surgical groups (12 patients each) underwent either a left or right endarterectomy for a symptomatic atheroma of the ipsilateral carotid artery. The control group consisted of 12 patients who either demonstrated minor or nonexistent carotid abnormalities or a TIA distribution that was contralateral to what would otherwise have been a surgically treatable lesion. Patients were tested before surgery and again 6-8 weeks later with the WAIS, WMS, and other neuropsychological measures. Significant improvement on some measures at follow-up was strictly equivalent across all groups and was attributed to practice effects.