MARY LOUISE KELLY, HOST:
Recent memory lapses by both President Biden and former President Trump have prompted lots of amateur speculation about their mental fitness. Experts, though, say those slips could be signs of normal aging or signs of nothing at all. NPR's Jon Hamilton reports.
JON HAMILTON, BYLINE: Last week Biden confused the president of Egypt with the president of Mexico. In January Trump appeared to confuse Republican Nikki Haley with Democrat Nancy Pelosi. Dr. Zaldy Tan says those errors on their own don't mean much.
ZALDY TAN: Some people are reading too much into little snippets of interviews without really knowing what's going on behind the scenes.
HAMILTON: Tan, who directs the Memory and Healthy Aging Program at Cedars-Sinai Medical Center, says a brain glitch can happen to anyone.
TAN: We've all had them. It's just that we are not public figures, and therefore, this is not as noticeable or blown up.
HAMILTON: Tan says aging just makes a momentary lapse more likely.
TAN: Even the so-called successful agers - if you measure their cognitive performance, you will see certain changes compared to their baseline.
HAMILTON: Tan says one of these changes is a decrease in the brain's processing speed, which can mean decisions take longer.
TAN: That is more important for, let's say, a race car driver or an airline pilot than it is for someone who is doing an executive-level job, where there's a lot of support and a lot more time to do planning and decision-making.
HAMILTON: Certain aspects of memory also change with age. For example, a healthy older brain retains its ability to learn and to store information. But Tan says retrieving a given fact may be harder.
TAN: Trying to remember that name of the restaurant that they were in last weekend or the name of the person that they met for coffee - that is not in itself a sign of dementia, but it's a sign of cognitive aging.
HAMILTON: Another type of memory affected by aging is the kind we use to temporarily keep track of a phone number or a password. It's called working memory. And Dr. Sharon Sha, a clinical professor of neurology at Stanford University, says it tends to fade a bit in later life.
SHARON SHA: Our working memory is, on average, about seven digits. As we age, potentially that might diminish this to maybe six digits - so slightly diminished but not zero.
HAMILTON: More serious declines in memory or thinking may indicate mild cognitive impairment, a condition that can lead to Alzheimer's and other forms of dementia. And these issues do become more common with every passing decade. But Sha says many times there's another explanation.
SHA: We often ask about sleep 'cause that can impair memory. We often ask about mood, like depression and anxiety. That can affect memory. We ask about medication.
HAMILTON: Sha says it's critical to measure an older person's current abilities against their performance earlier in life. A retired professor, for example, may do well on cognitive tests despite significant declines. During his presidency, Donald Trump says he aced a test called the Montreal Cognitive Assessment, or MOCA. But Shaw says that's just a 10-minute screening test, not an in-depth exam.
SHA: It gives a little bit of an assessment of executive function, a little bit of memory recall, a little bit of attention, a little bit of language. So it's a great screening test. But for a president, you know, we kind of expect that people should be perfect.
HAMILTON: Sha says it takes hours of testing to truly assess someone's memory and thinking. And she says there's no reason to administer these tests just because someone is in their 70s or 80s.
SHA: When we have an aging president, it doesn't mean that he will get dementia. In fact, he has a lot more experience than you and I do, so I think that should be valued also.
HAMILTON: Studies support that view. They show that an older brain is more likely to arrive at the correct answer even if it takes longer to get there. Jon Hamilton, NPR News. Transcript provided by NPR, Copyright NPR.
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