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In the days after Thursday’s presidential debate, one of the questions that was asked on the stage seems to be lingering in the public debate: How would the candidates address concerns about their capability to handle the job in their 80s?

Both candidates — Joe Biden, now 81, and Donald Trump, 78 — would set a record for the oldest president in office, and both have faced speculation about their cognitive abilities. On the debate stage, Biden and Trump both displayed behaviors that raised red flags from their audience: The current president had slurred speech, some garbled answers, a pause that resolved in a non sequitur; his opponent offered answers that often bypassed logical reasoning, and lied about easily verifiable facts.


Between the two, it is Biden who has been subject to more scrutiny, possibly due to his overall performance, in which he also looked frail.

But was the president’s demeanor a display of troublesome symptoms or just of regular aging, perhaps on an especially bad day? Medical experts, who are loath to engage in any kind of armchair diagnosis, told STAT repeatedly that it is essentially impossible to tell much about the president’s cognitive health without an in-person assessment. Several declined to comment at all, concerned about the escalating level of political exploitation of a medical issue, real or presumed. A few did, however, share insights into what “normal aging” looks like and what should be cause for concern.

Sharon Sha, who heads Stanford University’s Memory Disorders Division, said cognition is a broad term that comprises several functions, such as executive functioning (the ability to plan, multitask, organize), memory, paying attention, and language functions. All of these tend to change with age, but not always in a way that worsens them, or compromises them irreparably. “What we tend to see as we get older is that processing speed [change]. So how quickly we’re thinking and analyzing information can slow down,” said Sha. “But that doesn’t mean that there aren’t things that can compensate for that.”


Studies have shown that while it may take longer for older adults to process information, they often still do it correctly. But they have also shown that experience and judgment often improve with age. “With normal aging, there are some declines in cognitive function, and there are actually some increases,” said John Rowe, a professor of health policy and aging at the Columbia University Mailman School of Public Health. Vocabulary, for instance, expands with age, as does the ability to resolve conflict, and emotional stability.

“The declines that we see, in normal aging, in the absence of disease, are usually associated with speed of processing and retrieval of information,” said Rowe, noting, for instance, that someone may meet a friend or acquaintance in the street and have trouble recalling their name quickly. “That’s normal aging. That’s not dementia,” he said. Sha agreed, adding that it’s a matter of degrees. We may get slower at recalling things such as phone numbers, and memorizing them might become more challenging, but that doesn’t mean we have no memory capacity left.

“The processing speed is one that we see slows down, but not to nothing,” Sha said. Similarly, she said, we may struggle to remember a long series of numbers, or a full grocery shopping list, but that doesn’t mean we remember no numbers, or that we get home from the shop with an empty bag.

The situation is different when it comes to mild cognitive impairment (MCI), a disorder in which patients experience more severe forgetfulness — misplacing or losing things, missing appointments — in a way that interferes with their daily activities. About 10% to 20% of people 65 years and older develop MCI, and about 10% to 15% of them will go on to develop dementia, often Alzheimer’s disease, said Rowe. “But most of them will not. And in fact some of them actually improve with age as they get used to dealing with this. And they use memory tricks and, and aids and things like that in order to cope with those problems,” he said.

When someone presents the symptoms of MCI, clinicians need to evaluate the seriousness of the issues, and whether they are intermittent or consistent, said Rowe. Occasional incidents can be associated with external factors — say, in the case of the debate, a cold that Biden said he had may have had an impact, or perhaps cold medications. “Many times it’s intermittent and it’s only associated with when they’ve had a couple drinks or whether they’re on some medication or having some particular stress or some particular procedure,” he said. And, unless it devolves into something more serious, said Rowe, MCI doesn’t really interfere with what one could consider the responsibilities of a president: make decisions, process complex information, apply wisdom or experience.

“We tend to see in our clinics that there can be people who have cognitive concerns or even formal cognitive impairment when we do testing, but the person is still able to work and function and live independently and do all the things that they used to do,” said Sha.

But not all experts STAT spoke with are in agreement. While stressing the caveat that without in-person assessments it’s impossible to get any reliable diagnosis, one expert (who asked not to be named for fear of attacks) pointed to other signals that should raise concerns in older patients: a gait that doesn’t involve a swinging of the arms, a lack of blinking, and an overall “masked” expression that doesn’t show much facial movement are all signs of someone who is at best not aging well, or could have a progressive disorder. And while such symptoms don’t necessarily point to irreversible causes, they still require medical attention.

For his part, Biden, as well as his team, seem to be writing his debate performance off as a bad day. This, said Sha, points to another important element to keep in mind when trying to establish the health of an older person, as there are, indeed, bad days. That said, though, it’s crucial to understand how those bad days compare to the baseline — whether they are the norm, or an exception. “Oftentimes when I see a patient in my clinic, I ask family and close friends and whoever comes … to provide some accessory history to understand compared to baseline, is this a change?” said Sha.

Fundamentally, she said, it’s essential to stop considering aging, per se, a problem — be it with presidents or anyone else — and understand that, just as our bodies age yet still remain capable of functioning, so does our brain. “What we see in other cultures [is] that people at that age are contributing a lot more than we typically see in this country, and maybe not as presidents, but definitely to a family unit or other parts of society,” Sha said.

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