re #16: Ditto. (-:
But according to some of the studies I've seen reported in the press lately, precisely things like crossword puzzles if you've always done that, or playing an instrument you already know how to play, are what don't help as much, because you're not actively learning something new. The brain exercises that help are when you try new things and make your brain generate new neural connections -- possibly ones that will later offer alternate paths around the tau tangles or whatever.
I confess I was bummed about that because I like crosswords and sudokus too, even though they're not at all new for me. But lately I've added cryptograms to the mix, which is kind of a fun short-term change, and Free Cell instead of Taipei/Mahjongg Titans.
I don't trust the commercial websites that claim to offer brain-training games now, but computer games seem promising in theory, so I hope that eventually some of the nonprofit ones that have been used in recent studies (I think one was in California) will become available.
The unsettling thing I've read is that recent studies suggest that the actual onset of memory loss is about 10 years before the symptoms that currently define the diagnosis. Apparently people who self-report that they can't remember words are indeed more likely to have real trouble functioning 10 years later. If that's true, I may be one of them, because I feel like I'm noticing it more just in the last couple of years. (If I have a heart attack, tell them to autopsy my brain.)
But if the bilingual results hold up over the next few years, maybe I'll plan to move to a nursing home in another country when the symptoms get worse, and that would at least guarantee the language practice. (-:
I've also read that things that force you to combine right-brain and left-brain activity are good brain exercise. There are exercises I've seen done in choral warmups where you have to cross your hands and legs over the imaginary plane that bisects you vertically, and that's supposed to do something to help your brain integrate the mental and physical aspects, the conscious/rational and subconscious/instinctive. I can imagine it might also help build new neural pathways.