The purpose of this study is to determine how well patients undergoing carotid artery angioplasty and/or stent-supported angioplasty for the treatment of carotid artery stenosis will perform on a battery of tests to assess brain function before and after the procedure. This study will serve as a pilot project: (a) to determine incidence of neurologic/neuropsychometric change in patients undergoing carotid artery angioplasty and/or stent-supported angioplasty, and (b) to ascertain the time it takes for these changes to resolve.