BOSTON -- We all forget the keys occasionally, or what we did the day before. But when you're a senior citizen forgetfulness can be frightening and perhaps a sign of dementia, for which there is no cure.

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NewsCenter 5's Heather Unruh reported that there's now more evidence that an active mind may significantly lower that risk.

They play poker twice a week for fun, and a little change.

"We play 5 and 10, and we have a kitty, and you can't bet more than a quarter," card player Florence Rose said.

But they may be substantially upping the ante when it comes to brainpower. A new aging study has found certain leisure activities played regularly may stave off dementia.

The study found those who did the crossword puzzle four times a week were 47 percent less likely to develop dementia than those who did not.

Seniors who played musical instruments, board games or read regularly had similar risk reductions.

"The findings are significant," Hebrew Rehabilitation Center for the Aged spokesman Richard Jones said.

But epidemiologists are quick to point out the 20-year study of more than 450 seniors in this week's New England Journal of Medicine offers no proof, only observations. And it has limitations -- participants were predominantly white.

"However it's hard to imagine how the results that were demonstrated in the research wouldn't apply to people belonging to other groups," Jones said.

Experts say it's possible leisure activities increase connections between nerves in the brain, but they don't really know. One thing is certain, unlike drugs they have no harmful side effects and may stack the deck in your favor.