If only it were that easy. A study in Nature suggests that these brain games have little effect on the areas of the brain that control reasoning and memory, which are the core losses with dementia. There is no evidence that they prevent the progression to Alzheimer's disease. Yet the "brain fitness" industry has a $300 million footprint in the marketplace which, with the coming of age of boomers, is expected to grow to $5 billion over the next few years.
Source : http://www.stltoday.com/lifestyles/health-med-fit/best-ways-to-control-memory-loss-improve-thinking/article_5169e389-be0c-521e-a5ab-f4aa9aedc72a.html