Can you have Alzheimer's without symptoms?

Q. I’ve heard that many older adults have signs of Alzheimer’s disease in their brains but don’t seem to have cognitive problems. What might explain that?

A. It’s an intriguing phenomenon indeed. Research indicates that more than 30% of people over age 70 who have no apparent problems with memory or thinking skills have significant amounts of amyloid plaque — and over 10% even have substantial levels of tau tangles — in their brains. These abnormal proteins accumulate in the brains of people with Alzheimer’s disease and are implicated in the progressive degeneration that eventually robs them of the ability to care for themselves.

It may be that some people with these brain deposits but no noticeable cognitive problems simply aren’t showing symptoms yet. That’s because amyloid can accumulate in the brain for up to two decades before memory loss becomes apparent.

But another factor may be in play, one that we have some control over: how we use our brains. People with no dementia symptoms may have greater cognitive reserve. That term refers to the brain’s capacity to adapt and compensate for damage. Scientists believe people can enhance cognitive reserve by engaging in mentally challenging tasks such as taking up a new skill like gardening or painting, learning a new language or instrument, or working an intellectually stimulating job.

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