Mastering the latest fitness craze-keeping your brain healthy at any age Judging from the worldwide popularity of the brain game, Nintendo DS, and such mind-bending puzzles as SuDoku and KenKen(R), keeping one's mind as limber as an Olympic athlete is an international obsession. With forecasters predicting over a million people with dementia by 2025, today's young and senior population have a vested interest in keeping their grey matter in the...