A new study appearing today in the Journal of Neuroscience details for the first time how “mini-strokes” cause prolonged periods of brain damage and result in cognitive impairment. These strokes, which are often imperceptible, are common in older adults and are believed to contribute to dementia.

Or maybe even brain fog and gradual physical debility. (my comment)

http://www.urmc.rochester.edu/news/story/index.cfm?id=3699