Effect of Raised CBF During CEA on Cognition in DM Patients

The purpose of this study is to determine if we can reduce the incidence of cognitive dysfunction - difficulty in performing certain pencil-paper, memory, finger dexterity and thinking type of tasks called neuropsychometric tests - in patients with adult onset diabetes mellitus (DM) undergoing surgery on the carotid artery (CEA). We hypothesize that cognitive dysfunction can be decreased in patients with type II DM by augmenting cerebral blood flow with a shunt during carotid endarterectomy compared to patients with Type II DM who are treated with "conventional" management in which a shunt is placed only if the electroencephalogram (EEG) indicates cerebral ischemia.