A Reason Why Memory May Falter With Age

Sept. 12, 2005 -- Researchers may have learned why some older adults have glitches in short-term memory.

Those seniors may get distracted by irrelevant information, write Adam Gazzaley, MD, PhD, and colleagues in Nature Neuroscience.

Age, Attention, and Memory

"Attention is a two-sided coin," Gazzaley tells WebMD. "It can be both focused on what's relevant as well as ignoring what's irrelevant."

"What we found is that in normal aging, focusing on what's relevant is just not enough. You also need to filter out information that's irrelevant or distracting," he continues.

"We found that there's an association between older adults' ability to filter distracting information and their ability to remember relevant information. So essentially it seems to cause an interference in remembering what they should be remembering," Gazzaley explains.

Gazzaley is an assistant professor of neurology and physiology at the University of California, San Francisco, and an adjunct assistant professor of neuroscience at the University of California, Berkeley.

Attention Test

Gazzaley and colleagues showed pictures of faces and landscapes to 17 young adults and 16 older adults.

The young adults were 19-30 years old. The older adults were 60-77 years old, healthy, and well educated.

In one test, participants were told to focus on the faces and ignore the landscapes. The opposite instructions were given in another test. In a third test, participants didn't have to focus on either type of image.

Afterward, participants took short-term memory tests of the images. Meanwhile, their brains were scanned by magnetic resonance imaging ( MRI).

Age Gap

The results showed that young adults had no problem ignoring irrelevant information. Some (but not all) of the older adults had a harder time overlooking unimportant information.

Brain scans backed that up. The young adults' brain scans showed activity in a part of the brain that focused on the important images. The older adults' brain scans showed activity in the same area. But the seniors' scans also showed brain activity focusing on the irrelevant images.

"These data suggest that older individuals are able to focus on pertinent information but are overwhelmed by interference from failure to ignore distracting information, resulting in memory impairment for the relevant information," write the researchers.

Exceptional Elders

Some of the seniors did just fine on the tests. "That's very interesting to us," says Gazzaley. "That gives us hope that maybe we can improve these degenerating abilities."

As a group, older adults "typically show both a short-term memory deficit as well as a problem with suppressing irrelevant information," he says. "This was not true for all of the subjects in our study."

Some of the older adults "actually had preserved short-term memory abilities as well as [the] ability to suppress irrelevant information," says Gazzaley.

Those elders focused their attention as instructed, ignored everything else, and successfully used their short-term memory.

The researchers want to learn how they did that. "Some of our future studies are to now characterize what is it that makes these individuals experience successful aging," says Gazzaley.