Understanding the aging brain

If Joe Biden and Donald Trump are on the ballot in November, they’ll be the oldest presidential candidates in U.S. history.

How does age affect our memory, cognition and even the ability to be president?

Today, On Point: Understanding the aging brain.

Zaldy Tan, physician. Memory and geriatric medicine specialist. Director of the Cedars-Sinai health system Memory and Aging Program and the Goldrich Center for Alzheimer's and Memory Disorders. Professor at the David Geffen School of Medicine at UCLA. Author of "Age-Proof Your Mind: Detect, Delay, and Prevent Memory Loss--Before It's Too Late."

Part I

DEBORAH BECKER: The United States is facing an unprecedented moment in this year's elections with the oldest presidential candidates in the nation's history expected on the ballot. President Joe Biden's 81, his presumed Republican challenger, former president Donald Trump is 77 years old, no matter who wins in November, it's likely the U.S. will have its oldest president ever.

The issue of age got new attention earlier this month after the release of a report on Biden's handling of classified information, the report described the president as a quote, "Well-meaning elderly man with a poor memory." Biden pushed back.

PRES. JOE BIDEN: I'm well-meaning, and I'm an elderly man and I know what the hell I'm doing.

I've been president and I put this country back on his feet. I don't need his recommendation. It's totally --

REPORTER: How bad is your memory? And can you continue as president?

BIDEN: My memory is so bad, I let you speak.

BECKER: Donald Trump has had some of his verbal gaffes come under scrutiny and at a rally in Nevada last month, he told the crowd, he's fine.

DONALD TRUMP: Tell you what, I feel sharper now than I did 20 years ago. I really do. I don't know. It's probably not true. (CROWD CHEERS) 

And I think anybody running for president should take an aptitude or a cognitive test.

BECKER: Polls show Americans are worried about the age of the presumptive candidates. In a recent Quinnipiac poll, more than half of the voters surveyed said they're concerned about the age of both men. So how old is too old to be president?

Many of our listeners have weighed in on this. Douglas from Columbus, Ohio left us a message. He's an 80-year-old retired physician who says, after a certain age, his stamina was affected.

DOUGLAS: I retired at 75 because I did not have the vigor to last the whole workday. I think that President Biden is too old to continue as president, because it's an extraordinarily demanding job.

I can't see how anybody in his age group has the vigor to remain sharp for the length of time that he would have to for his second term. I think Donald Trump is also too old. Plus, he has other issues that I think make him an inappropriate president.

BECKER: We also heard from Daryl, from Marshall, Minnesota.

He says age is just a number.

DARYL: I took care of my grandfather until he was 97 years old, and he was just as sharp on the day he died as he was as a young man that I remember. I think it all depends on the person, and each person has to be judged on a case-by-case basis.

BECKER: So how do we judge the effects of aging?

Can we? I'm Deborah Becker. In for Meghna Chakrabarti, and this is On Point. Today, we'll spend the hour trying to understand what happens to our brains as we age. Joining us from Los Angeles is Zaldy Tan. He's a practicing physician and director of the Cedars-Sinai Health System Memory and Aging Program, and the Goldrich Center for Alzheimer's and Memory Disorders.

He's also a professor at the David Geffen School of Medicine at UCLA. Zaldy, welcome to On Point.

ZALDY TAN: Hello, Deborah. Thank you for having me.

BECKER: I guess I want to start by saying, how do you assess someone's cognition? What should we be thinking about as we are having this conversation about age? First more broadly, and then we'll talk about political candidates.

TAN: So when you think about assessing someone's cognitive abilities, it really depends on the context, right? So as a physician practicing and specializing in memory disorders, what I typically ask the patient and the collateral informant, which is typically an adult child or the spouse, is what has changed?

We all have different baselines and there is massive inter-individual differences in terms of cognition and intellectual abilities and other cognitive abilities. So the important thing is, has there been a change? And that's the key information that I need, and I think everyone should be aware of.

For example, someone has been very poor with names even when they were younger. And then add in cognitive aging to that, wherein there is decrease in sensory perception, decrease in processing speed then, and that may be more problematic as you get older. Whereas it was just an inconvenience when you were younger.

So those are the kind of things that I ask about. And of course, there are unmistakable signs of memory problems like forgetting to pick up a grandchild from school when they've been doing this for years, or getting lost while driving in a familiar place.

These kinds of things are more obvious, but the earlier stages of memory issues versus normal cognitive aging is not so easy to distinguish.

BECKER: You mentioned context and I think there's a lot going on here when we're talking about this, especially in terms of candidates running for really important jobs, right?

You've got the stress of a campaign and you're talking about going into probably a job that is one of the most stressful that you could possibly hold. So I guess, we have to think about that. We're evaluating people who are in this sort of real chaotic kind of high-pressure campaigning all the time.

And of course, President Biden's also running the White House, but also folks have brought up that you need to think about the candidates' medical history, what medications they might be on and their background. And we heard from listeners, many listeners about this, everyone knows about aging of course, because we're all doing it.

But Alan from Somerville, Massachusetts called and brought up this about President Biden. Let's listen.

ALAN: When discussing aging, with respect to Joe Biden, we do need to pull in the context that he had a stutter growing up and one of the ways he learned to overcome that stutter was by just replacing a noun with another noun. That's a common way to get over a stutter.

He's been mixing up names his whole life. When he mixes up names, that's not entirely to do with his age.

BECKER: So Zaldy Tan, what do you think about that? Is that one of the things that you were talking about when you said, we need to think about context when we're trying to determine exactly what someone's cognitive state is and how does this trying to overcome a stutter affect someone's cognition and the appearance of their cognitive abilities?

TAN: Surely if someone has a baseline or a long-standing speech impediment, that certainly should be taken into consideration when someone is observed to be mistaking words, for example. With age, typically speech and language functions remain largely intact. But obviously if they have a baseline speech impediment, that's not going to go away.

And it's correct that some of these may become more problematic or more noticeable as you get older, because vocabulary and speech is only one of the cognitive domains. Remember that when you think about cognition and your brain and thinking, it's really several cognitive domains.

It's attention, it's memory. Its executive function, language, visuospatial abilities. So these all will have to be in tip-top shape in order to do any challenging task. So if any of these fail or if you have started with weakness in any of these domains, this will manifest in a different way.

A good example will be attention, like for example, when you get older, simple attention where if I ask you to remember, let's say five digits, 38943, that usually is okay. And doesn't decline with age, but complex attention or divided attention tends to decrease or become more compromised with age.

So for example, if someone is driving while listening to music and watching out for that exit sign, exit in the freeway, that could become a compromise. They might miss that exit because of the divided attention. In the same way, if I have a speech issue to begin with, and then I'm distracted by lights, camera lights or someone in the background, then that could bring out, some of the weaknesses will become more prominent.

BECKER: So is it more multitasking can be more challenging to an aging brain? Is that what you're saying? Or?

TAN: Yes. Multitasking is considered part of executive function. Executive function is our brain's ability to plan, sequence things, problem solve. So that could become compromise as you get older.

Then so multitasking is a combination of executive function and divided attention, right? So your ability to focus on multiple tasks simultaneously. Such as, for example, if you're walking an obstacle course and answering questions, if you try that, I think a lot of us will find it a bit challenging.

And of course, if there were multiple things that someone has to keep track of at the same time, that can be very challenging for anyone. But of course, as you get older, that becomes more compromised.

BECKER: You mentioned assessing someone, speaking with their loved ones, asking them if they have new challenges, doing tasks that previously weren't challenging.

But I really wonder, because I'm really good at denial, Zaldy. I wonder how you have reliable narrators here and objective observers, by which to make the assessments of someone's cognitive ability. I'm sure many people probably think they're fine and they may in fact have a problem and even their loved ones may want to believe that, as well.

So how do you cut through that and make sure that you're getting at the truth?

TAN: That's a very good point, Deborah. When people see me in my clinic, typically it's either someone is what we call worried well, wherein they are independent, they're doing quite well in their day-to-day activities.

But they are taking them a while to come up with a name of a person that they think they should remember their name when they meet them in the supermarket, for example. So benign things like that. Or it's someone who absolutely is convinced that there's nothing wrong with their memory, but their wife or their adult son or daughter is dragging them into the clinic and then they're unhappy about it.

So denial is a very powerful thing in both directions, right? For people who I've seen this in, for example, in adult children, when their parent, let's say, is living alone and they come into the home and they see food that is expired, and they see that the house is unkempt, and they see piles of mail or unpaid bills.

It's easy to blame that or to attribute that to getting older or their vision is not so great. Maybe they're just not that motivated as they used to, now they're retired. But that can also be a sign that the patient is or the person is starting to fail cognitively.

BECKER: Okay.

TAN: That they're not able to keep up with their day-to-day things.

Part II

BECKER: We're talking about our brains and aging. What happens to our memory, our cognition, and what should we consider as we think about presidential candidates like Joe Biden and Donald Trump? A lot of you, our listeners, have weighed in on this and their opinions about aging and the candidates.

We heard from Joyce, from East Falmouth, Mass., and she thinks we should have younger presidential candidates. Here's what she said.

JOYCE: I can see Joe Biden almost fading every time you see him. And I just worry, I don't know why we don't have something in place, to have somebody younger running.

BECKER: And yet Barbara from Los Angeles, California left us a voicemail and said, you know what?

Age means wisdom.

BARBARA: When I make decisions, I have the benefit of 50 years of experience and 50 years of results from those experiences to draw upon, so I don't have to churn information and wondering whether or not option is good or bad. I have a plethora of memories to go back and compare similar situations to. And say, "Oh, this was the outcome in that instance, and these are the things that led to that."

Not so, therefore, I can say with some authority that this might be a good choice for me.

BECKER: Alright, when joining us to talk about this is Zaldy Tan. He's a practicing physician and director of the Cedars-Sinai Health Systems Memory and Aging Program, and the Goldrich Center for Alzheimer's and Memory Disorders.

He's also a professor at the David Geffen School of Medicine at UCLA. And I'm wondering, Zaldy, when you hear those very differing viewpoints about, I want the experience and wisdom that age can bring. You know what, I'm concerned about age and about vitality in a leader. What do you say to folks?

Do you say, is it just a number and it really depends on or how would you characterize your description of the aging brain to folks?

TAN: So Deborah, when I think about the aging brain, where I talk to people about aging brain, I emphasize to them that not everything is sensitive to age-related changes.

For example, cumulative knowledge, experiential skills, these are well-maintained even into advanced age, that certain aspects of memory are stable for even as you get older. Although new learning, for example, there could be more problems and some decline of retrieval of newly learned information, that can be changed, that can change with age.

But there's a lot of things that do not change, and in fact, are relatively stable. Of course, you can't minimize experience and wisdom. And of course, person's principles and etc., do not change with age. However, there are things that do change with age, such as your ability to quickly process or transform an information to make a decision.

So basically, tasks that require speed of information processing, can decline with age. So what I tell people is, what is the job? What does the job entail? Does it require speed of information processing and thinking? Certainly, if you're giving a press conference, that is required, but is that an essential role for a president of the United States, or is it more important, the other qualities that do not change with age? Is that more important? So I think you have to put things again in context.

BECKER: So tell us what's happening. Let's talk about some of the science and what we know about what's going on in the brain as we age.

What are the differences between a three-year-old brain and a thirty-year-old brain and a 70-year-old brain? What have we been able to measure?

TAN: So when you think about the brain, it's really a life course. It's really growth and development and stability, and then a slow decline.

But in a normal cognitive aging, the decline should be slow and subtle enough that it should not affect your performance of day-to-day tasks or even your job. In the past several decades, we've learned so much about the brain growth and development, thanks to cognitive science, but also because of the structural information from brain MRIs, for example, that we are able to look at gray matter volume connectivity of the different parts of the brain, the prefrontal medial temporal parietal cortices.

We also have more information about white matter connectivity between different parts of the brain. And of course we have the cognitive science of aging. An important concept, I think for everyone to remember is that we all have different baselines, and there's these concepts of, three important concepts that I'm just gonna briefly discuss.

First is reserve. Reserve or brain reserve or cognitive reserve is your accumulation of brain resources during your lifespan. For example, education is known to build brain reserves so that people who are well educated or have a lot of formal education, or remain cognitively stimulated during late life are less likely to develop dementia in other age-related changes. That's reserved.

There's also maintenance. Maintenance is a preservation of these resources. And even if your brain reserves, for example, are not the greatest, but you're living a healthy lifestyle and you're maintaining whatever you got, then that's a good thing as well.

And then compensation. Compensation is the deployment of resources in response to demands on your cognition. So all these things are at play and will affect someone's performance in any task as you get older. Reserve, compensation and maintenance. And the other thing I want to mention is inter-individual variability is massive in terms of cognition.

There are 80-year-olds who would outperform forty-year-olds in certain tasks. And between 80-year-olds, there will, there could be massive differences in terms of what they're able to do, again, because of differences in their brain reserves. In their maintenance. And in their ability to compensate.

BECKER: So then in actual physical, the actual physical brain, do you see a difference? Maybe we don't see it and we're not perceiving it. But say for example, is there a difference in gray matter? Or is there a difference in white matter connectivity as folks age and we're still learning about what exactly that means and how it might present itself to be visible to others?

Is that, do we know that?

TAN: Oh, absolutely. If you show me an MRI of, for example, a 30-year-old and an 80-year-old, I can tell you very quickly which one is which. And the reason is because just like our muscles, just the rest of our organs, the brain does experience structural aging.

So we have talked about cognitive aging up to this point. And then when you talk about structural aging, this is things that you can see, right? So when you get an MRI of an 80-year-old, you'll see that there is an age-related decrease in total cerebral volume, we call it. There is an enlargement of the ventricles, which are the part of the brain, the center where we make cerebrospinal fluid.

In certain cases, even the hippocampus, which is the short-term memory center of our brain, shrinks. But it's a question of how much shrinkage, right? If there is focal, for example, what we say, focal hippocampal atrophy, that's a sign of Alzheimer's disease. So there are certainly changes in the aging brain compared to younger.

BECKER: So we do see it. And do we know for certain that some of that shrinkage or change in physical structure has certain effects on how the brain functions? Does it not, does it compromise someone's executive function or other ability if there are these physical changes in the structure?

TAN: Yes, there is a correlation. So for example, if someone has what we call white matter changes in the MRI, which is a sign of chronic small vessel disease, that's essentially showing that there's a problem with sort of the cables that the white matter recall it, that transmit information from one part of the brain to another. You can see a slowing off of thinking and processing in these people.

Retrieval of information can be challenging for these people. And we test this in the clinic by having them, let's say remember a name and address of a person and then five minutes later, having them repeat the name and address, and sometimes they would confuse which state it was or what the street number is. So that could be correlated with changes, structural changes in the brain.

BECKER: When we talk about, we've talked a lot about memory, right? I wonder, there are so many other things though, that our brains obviously control.

Explain briefly, because I know people spend many years studying this. But I wonder if you could explain briefly how to look at the complex systems that the brain oversees and how you take that into account when you are considering whether someone is facing some sort of mental decline because of aging.

There are a lot of other things besides memory, right?

TAN: That's correct. I'll give an example. For example, if you are at a party and you meet somebody, maybe her name is Mary, let's say. So when you meet with Mary, and you talk to her for five minutes and she tells you what she does and where she's from.

And you're in a room full of people, right? So your attention has to be, your attention abilities, which is one of the content functions, has to be intact, specifically divided attention, which is your ability to focus on the information that Mary's transmitting to you.

That's also called selective attention. That has to be intact, and that can get compromised as you get older. Of course, we didn't even talk about sensory perception, right? So if I'm trying to listen to Mary talk and I have a bit of hearing loss, then that could compromise the information that my brain has access to.

But let's say your hearing is intact. You hear everything that Mary says. It goes into your hippocampus, which is your short-term memory center. Your brain has to encode that, encode it and store it somewhere in your brain and be able to retrieve it later on so that when you see Mary, in the supermarket a week from now, and she says, oh, hi, it's you. And I'm like, who is this lady? I would be happy, be able to retrieve that. And remember, memory is also, there's also different types of memory. There's procedural memories, like in my ability to drive to the supermarket and back home visual memory, my ability to see Mary's face and recognize the pattern.

Then there is the verbal memory, which is coming up with Mary's name. So all of this need to be intact, even in that very simple cognitive task of remembering someone that you met from a party a week ago. So if any of those fail, then I will not remember who she is because I wasn't paying attention, or my attention was compromised even if I tried to pay attention.

Or if Mary's memory, her face, her name, never made it to my long-term memory, because I have a hippocampal issue or problem. Because I'm starting to have Alzheimer's disease, for example, then that's never going to be encoded and therefore it's not available for retrieval.

BECKER: I want to ask you also about folks called super-agers. And we had someone leave us a message and she apparently has been considered or described as a super-ager. And ironically, her name is Mary, we should say not the Mary you were just referring to, but she's 84 years old.

She called us from Salt Lake City, Utah. Let's listen.

MARY: Recently I was concerned about my memory, so I took a three-hour neuropsychologist test on memory and problem-solving functions. I was scored what they call in the business, a super-ager. The tester paid me the ultimate compliment at the end. She said she hoped when she was my age, she would have a brain as good as mine.

BECKER: That's Mary from Salt Lake City, Utah. Zaldy, what's a super-ager? And how does someone get to be as lucky as Mary?

TAN: Good for Mary. Congratulations to her. Yeah, she's lucky. Yeah, so cognitive super-agers is an informal term that people use to refer to folks who don't seem to have a measurable decline as they get older, in terms of the cognitive functions that we've been talking about. Attention, executive function, working memory, et cetera. And again, this is typically an interplay between genetics. As well as environmental factors, right?

We don't know Mary, but I assume that she has lived a pretty healthy life, meaning minimizing your exposure to certain neurotoxins, alcohol being the paramount neurotoxin that we are, that a lot of people are exposed to. Perhaps she exercises, perhaps she is very social and engages in intellectual mental stimulation and get a good night's sleep.

So even someone who's genetically blessed, if they don't do the things that they need to do in order to maintain their brain reserves, they will notice changes that they will not be able to maintain that. But for someone like Mary, let's say she is genetically blessed, in terms of her brain structure and cognition, and then she does the right thing. Then these are what we would call super-agers, where if you compare them to their baseline, let's say 10, 20, 30 years ago, there is no noticeable change.

BECKER: And so because we're doing so much research and you're doing so much research on this, I'm wondering, when you look at the science right now what is most exciting to you when you look ahead about what we're learning about the brain and how we can perhaps mitigate some of the negative effects of aging on the brain.

And what's exciting to you about this?

TAN: You know what's exciting to me, Deborah, is that the advances that we have in medicine, in neuroscience, public advances in public health measures are rising standards of living and improvements in education, nutrition have really not only lengthened the human lifespan, but also if you compare long-standing studies that, for example, started in 1940s. And you compare someone, let's say, who was 50 or 70 or 80-year-old in the 1960s to someone who's that age, the equivalent age, now. We actually find that the debilitating effects of aging are increasingly delayed to later stages of life.

And more than that, when they look at these studies that people, that they have people that they follow over decades, what has been found in multiple studies, at least in the Western Hemisphere, is that the incidents of dementia, Alzheimer's disease actually is going down. Not going up. Again, of course, if you consider the aging population, there's going to be more people with dementia now because we're all living to the age of risk. But if you just look at incidence rates, there's actually less.

Part III

BECKER: What I'd like to do at the end of the show here, is talk about brain health and how do we maintain it a little bit.

So I wonder, Zaldy, you were mentioning before the break that we're seeing aging effects delayed. There's actually a decline in the incidence of dementia, which I think is probably heartening for a lot of folks to hear. But you mentioned also that alcohol is a neurotoxin and can affect people's brains and perhaps have negative effects.

And exercise is good for us, but what do we know about things that folks can do to make sure that their brain health is at least maintained, maybe improved?

TAN: Absolutely. And I think this is the fallacies that we have no control over our brains. And it's partly because the research in cognitive health and brain health is really lagging behind for example, heart health.

When we get a checkup with our primary doctors, we get an EKG or an electrocardiogram. Our primary care doctors whip out their stethoscope and listen to our heart and saying, your heart sounds strong, et cetera, it's because we have decades ahead in cardiovascular research compared to brain health research.

But lately we've found that there's really a lot of control we have in terms of our cognitive aging. There's really multiple factors that shape the trajectories of brain aging and our, what we call modifiers, of things like brain resilience, things like physical fitness or maintaining a healthy physical activity.

We tell people you have to have at least 150 minutes per week. Moderate physical activity in order for your brain and heart and your other organs to remain healthy. Social engagement has been found to be really important in terms of maintaining cognitive health. And in sort of the flip side, social isolation is found to be detrimental to maintaining brain health.

Other things like maintaining vascular health, like your blood pressure, for example, midlife blood pressure is one the primary determinants of cognitive health as we get older. Particularly uncontrolled, mid-life high blood pressure is known to be a risk for dementia. Metabolic diabetes is a risk factor for dementia.

Maintaining good blood sugars and minimizing insulin resistance is important. And then there's also in your inflammatory risk, and of course all of that is genetics, right? You tell, there are people who say I smoke, I drink, I don't sleep, I only sleep three hours a day, and I'm fine.

It's possibly because these people are genetically blessed and have more, but if you compare them to their peak. Let's say in their twenties or thirties, they still have experienced a decline because they're not living their life appropriately. So again, reserve maintenance and compensation.

BECKER: Okay. I want to bring in the voices of some more listeners, as we said, we got a lot of response to our topic today.

And first I want to bring up Opal. She's from Ann Arbor, Michigan, 75 years old, and she tells us how she's taking care of herself as she's aging. Let's listen.

OPAL: As far as aging, you're going to get older. You can't stop it, so you might as well do it the best that you can. And the way that I do it personally is I do breath work.

I learn how to sit still and meditate and be with myself. I know now, which was difficult for me when I was younger, to ask for help. You get surrounded by this group of wonderful people that do help you when you ask for help.

BECKER: Also, I want to bring in Sarah. She's from Santa Fe, New Mexico, and she left us a voicemail.

And this is an interesting point, Zaldy, and I'd like you to take both of these up. Her point is about how to exercise your brain when you're older and how society looks at older people. Here's Sarah.

SARAH: What I've seen actually is that I haven't had a decline in IQ, but I have a decline in outlets for using it.

That's due to ageism. There's a condescension and a contempt and the expectation of expendability that are particularly hard to penetrate, so it's hard even to go to a store. It's hard to maintain the involvement in one's profession. Our society's structured to render us invisible and irrelevant.

BECKER: So Zaldy, I wonder, what do you say first about Opal and meditation and breathing?

Do we know anything about how that affects the brain as of yet? And what do you say about ageism? And how it affects folks' ability to do some of the things that you say are beneficial for their brains, like using them and having social connection.

TAN: For sure. When you meditate and you breathe deeply it's really lowering stress.

And when you think about stress, what is stress, right? Stress happens when you feel like you have no control over the situation, and you feel that something is going to go wrong. And what happens there is a flight or fight response, right? Your cortisol shoots up. Cortisol obviously is a physiologic response that is needed in order to respond to an acute stressor.

But chronic cortisol elevation because of chronic stress is not good for you. And this have been multiple studies that have been done with high cortisol levels that it impairs your memory and your ability to teach. To think and process information and can be a marker of increased risk for dementia if sustained over long periods of time.

So meditation in a sense, really helps. And of course, with the breathing, oxygen is so important for our brains. Certainly, you don't need to breathe deeply, normally, in order to have enough oxygen for your brain, but your brain is one of the most highly metabolic organs. So it requires a lot of oxygen.

But one thing worth mentioning is that some people have undiagnosed obstructive sleep apnea. When they sleep, their upper airways, a soft tissue fall back into their airways and they get a decrease in oxygenation, what we call hypoxemia, multiple times during their sleep. And that is a risk factor for dementia over years.

Now shifting to ageism, right? It's really unfortunate because we are a society that really values youth and vitality even amongst our leaders, right? So sometimes I see our leaders come, going down, coming, stepping off of the plane and going down the stairs.

Of course, we hope that they don't fall. Older people have more tendency to fall. They have a lot of sensory issues, tactile issues, etc. Is that sign of physical vitality as important to us as cognitive vitality, which one's more important? But going back to ageism, unfortunately our society does have a mild obsession with youth, right?

BECKER: Mild? (LAUGHS)

TAN: And that's the hard challenge. And if you see someone, you know, let's say in the party and there's someone who's older there, our natural tendency is not to go to that person. At least some of us, I would, maybe you would, but some people will be like, "Oh, maybe it's going to be hard to talk to her.

Maybe she, we have nothing in common." And that is part of ageism and that goes into hiring practices as well. When you see someone older, you make the assumption that they're not going to be as sharp, they're not going to be as resilient and not be able to learn new things. That may not be true depending on the person.

BECKER: So I think, how do you think that's playing into this whole conversation about our presidential candidates?

TAN: I think it's like when you see someone who's  77, 80, 81, the normal tendency for some people is to relate that to what their memory, or what their own biases are about people that age, right? So they might look back at their grandmother or someone they met when they were younger. The thing with, an important thing to remember, Deborah, is that everyone is different and there's a lot of vital, active, intelligent, confident 70 or 80 years olds. But we ourselves may not have been exposed to them, because guess what?

They are active, they're hiking, they're doing their thing just like anybody else. And if we consciously or unconsciously avoid them in situations, then we will only be exposed to people of that age when they fail. They got memory problem, they get lost. We help them.

And then we have this concept. And of course, media doesn't help, because media portrays older people as impaired, forgetful. Incompetent. So this is really, the ageism in society is rampant. And again, our obsession with youth is problematic. And it clouds our vision of our opinion of what older people are and what they can and cannot do.

BECKER: It's also brought up this idea of perhaps some sort of measurement. Should there be a cognitive test for someone to lead the country? And again, our listeners weighed in on this idea. It's been debated now because of what's happening with the presidential candidates.

But here's Dennis. He's a listener from Montana. He's 77 years old. And he talked about some of the things that he does to keep himself fresh young, vital and he also talked about this idea of a cognitive test for elected officials. Here's Dennis.

DENNIS: I don't walk as fast as I used to.

I don't go up the hill as much. I don't run, but I still ride my bike. I work out five days a week. I think that's the key. I read a lot. I try to be involved in the world around me, to be concerned about issues, especially with this focus on aging. I feel like there's an opportunity to have an intergenerational conversation about age, and it's not for me about your age, it's about your ability, your desires, your functionality.

And so for Nikki Haley to say everybody over 75 should take a test if they want to run for office. I find that offensive.

BECKER: So I wonder, Zaldy Tan, is it possible to really get a handle on  how someone's aging brain is doing and their competence really? Is it possible?

TAN: Yes. So if one were to test their cognitive abilities and we get a good history. And again, we'll need a collateral informant, right? So typically, people who are very close to them, their wives or their adult children, have they noticed any changes? And then we do formal cognitive testing. Somebody mentioned earlier, sometimes it takes two to three hours of a neuropsychological test to really get to the bottom of how someone is doing, because as we mentioned, cognition is more than just memory. We have to test executive function, language, spatial skills attention. All of these things need to be tested. So it takes a while. Now, should they do it or not? I think the American public would need to decide that because remember.

Dementia memory problems is not the only age-related diseases that can affect someone as we get older, right? There's heart disease, there's cancer, there's stroke. Where does it end? For example, a physical fall could get your, get you into trouble more than the slow decline associated with cognitive aging.

So all of these things need to be put in context. And again, who decides? What is wrong is what's right. But can we do it? Yes, we can test someone cognitive function, but someone has to be willing. And again, what are we entitled to as in terms of confidential medical and illness information?

BECKER: As someone who's trained to understand aging and measure it and study it, is there anything that you've seen from either of the candidates that you would consider worrisome based on your knowledge at this point? That we may not, but maybe you might say maybe none of us can spend the time, or have the access really to look at every elected official in a way that could really make an accurate assessment.

But are there things that have happened so far that you've observed from either of the candidates that you find concerning?

TAN: I wouldn't say concerning Deborah. Does it give me pause? It does. Because I wonder what, just like anybody else, whether professionally trained or not, is happening, what is in the background, right?

So before they step into that podium and the mic, were they briefed? About obviously they are, because that's what presidents do. They're briefed about the ongoing situation. Who's involved, the names of the people, but what were they doing when they were briefed of this?

I imagined it's someone is like putting on the lapel mic and someone is fixing their hair. Maybe telling them where to sit and stand. So I think about divided attention, right? And selective attention. So if you have four or five things going on at the same time, and you are older, and we already said that divided attention gets compromised as we get older.

And then you step in the podium and there's 50 reporters there and some of them are in very distracting bright lights, all of that stuff. Any person can get distracted, right? And can mistake words. Because again, divided attention. So many things going on, but of course, someone who's older is more likely to be compromised in that highly charged and stressful situation.