Decreased blood flow to the brain can cause decreased cognitive function. Carotid disease can result in decreased blood flow to the brain. The investigators seek to assess this relationship prospectively through performing a battery of neurocognitive assessments, collection of serum markers of inflammation, and through neuroimaging at two points before intervention (2 months and 1 month before stenting) and at two points after intervention (1 month and 2 months after intervention). The goal is to provide prospective evidence to identify the extent to which carotid stenosis and hypoperfusion of the brain results in diminished neurocognitive performance, and see if serum biomarkers before and after stenting correlate with these findings.