 This study will be a multi-center trial to be conducted in centers across Canada and approximately 80 patients will be enrolled. Participants will be recruited from both stroke prevention N40 and memory clinics N40. For comparison, we will access the publically-available data using a very similar protocol being collected from normal controls N250, MCI N250 early MCI, N150 late MCI and AD patients N150 without significant white matter disease, who are participating in the Alzheimers Disease Neuroimaging Initiative ADNI-GO and ADNI 2, N800, to choose representative samples for comparison to those with scores 1 who represent the non-white matter disease group. 