Terrifying, but good to know. At 65 (too late for the Brain Initiative Program, dammit), I’m the youngest of three sisters. The oldest, 77, is in what’s being called early stage Alzheimer’s but I noticed changes in her cognition in her early to mid-sixties. The middle sister has cortico basal degeneration, which at the moment makes Alzheimer’s look not so bad by comparision. Our mother lived to be a very healthy and sharp 92 until she had a devastating stroke, after which she lived in a nursing home for another 4 years. Until my sisters’ issues, I figured healthy aging was in the bag for me as long as I did all the things I’m supposed to do. Now, the specter of dementia lurks in the shadows of my awareness, pretty much all the time.