Do cognitive activities speed up or delay dementia?

Research on cognitive activities and dementia.

I read an interesting article based on research a while back.
It argues that people who participate in cognitive activities like reading and doing word puzzles could help delay dementia. However, people who do many cognitive activities were found to have a greater drop in cognitive functioning when symptom hit.

Here is the article:
http://pagingdrgupta.blogs.cnn.com/2010/09/01/brain-exercises-delay-speed-up-dementia/?hpt=C2

Recreational therapists who work with this population may also be interested in this article on more effective treatments:

http://pagingdrgupta.blogs.cnn.com/2010/09/01/better-understanding-of-dementia-leading-to-more-effective-therapies