The Secret Life of the Grown-up Brain: The Surprising Talents of the Middle-Aged Mind - Barbara Strauch (2010)

Part II. The Inner Workings

Chapter 8. Extra Brainpower

A Reservoir to Tap When Needed

So if our middle-aged brains are—on balance—so masterful and marvelous, what can we do to keep them that way?

For an answer to that, there’s no better place to start than with a now-dead nun.

Her name—or the name she’s been given in the scientific literature—is Sister Bernadette, and she’s given us provocative clues to what may be the brain’s most powerful ploy. Sister Bernadette was a part of what’s been famously called the Nun Study. Since 1986, University of Kentucky scientist David Snowdon and his colleagues have studied 678 Catholic nuns in an extraordinary experiment to look at how the brain ages and why.

As part of the study, the nuns, members of the convent of the School Sisters of Notre Dame, have had periodic mental tests—how many animals they can name in a minute, how many coins they can count correctly, how many words they can remember after seeing them on flashcards. Through the years, they’ve also provided personal information—who their parents were, what illnesses they suffered, how many years of schooling they had—details that have been meticulously cataloged and stored in convent archives.

And perhaps most important, the nuns all agreed that after they died they would donate their brains, which are placed in plastic tubs and shipped to a laboratory where they are stored and analyzed.

Nuns are a particularly good study sample because you can usually eliminate a slew of activities—heavy smoking and drinking, for instance—that aren’t particularly good for a brain and skew results. And the Nun Study has had a score of fascinating findings, including suggestions that dementia may be linked to small strokes or insufficient folic acid in the diet. And, in an especially striking result, the nuns who used the most elaborate sentences—packed with more complex and optimistic ideas when writing autobiographies in their twenties—had a lower risk of dementia decades later.

Still, in the midst of such revelations, the story of Sister Bernadette stands out. Among the nuns, she was a class star. Early in her life, she had earned a master’s degree and taught elementary school for twenty-one years and high school for another seven. At ages eighty-one, eighty-three, and eighty-four, she aced any cognitive test thrown at her. Then, about ten years ago, after she died of a massive heart attack at age eighty-five, Sister Bernadette’s brain was sent to be analyzed, initially without its identity being known.

At first glance, the brain seemed fine. It weighed 1,020 grams, about normal. But, as Dr. Snowdon writes in his moving and personal book, Aging with Grace, about his relationship with the nuns he both studied and grew to love, a microscopic look at Sister Bernadette’s brain soon revealed something far different. There was, Dr. Snowdon writes, “little doubt that Alzheimer’s disease had spread far and wide. Tangles cluttered her hippocampus and her neocortex all the way up to the frontal lobe. Her neocortex had an abundance of plaques as well.” In fact, on one scale used to determine the degree of Alzheimer’s, Sister Bernadette rated the most severe, Level 6.

How could it be? How could a woman who was, up until the moment of death, a cognitive champ also have extensive plaques and tangles, the hallmark of Alzheimer’s disease? Expressing his own surprise at the time, Dr. Snowdon said, “Despite an abundance of plaques and tangles in her neocortex, the function of that brain region seemed to be incredibly preserved. It was as if her neocortex was resistant to destruction for some reason. Sister Bernadette appears to have been what we, and others, have come to call an ‘escapee.’ ”

An escapee?

Is that possible? Was there something in Sister Bernadette’s background—her richly endowed sentences, perhaps—that, although her brain had all the physical signs of dementia, had somehow protected her?

On one level it would be easy to dismiss the case of Sister Bernadette as interesting but odd. It would be easy if she were a fluke.

But she is not.

Take the case of the retired professor from London. The professor—he’s called the Chess Player in scientific studies—loved to play chess and was uncommonly good at it. As he played, he could easily think seven moves ahead. But at a certain point, he noticed a change. Although his wife and family thought he was fine, he was worried. He found he could think only four moves ahead. Convinced there was something terribly wrong, he went to the clinic of Nick Fox, a neurologist at University College London’s Institute of Neurology. No problems were found. The professor cruised through a battery of tests intended to detect early signs of dementia. A brain scan was normal. The professor, then seventy-three, continued to play chess, read history books, cook elaborate meals, do the family’s finances, and even learned how to use a computer. He also continued to have brain scans, which detected few significant changes.

Then a few years later, the professor died of causes unrelated to his brain. And much to the surprise of Fox and the professor’s family, an autopsy showed that the Chess Player’s brain, too, was riddled with the plaques and tangles of Alzheimer’s. The professor had what appeared to be an advanced case of dementia. Yet for years the only outward sign of it was that he could think four chess moves ahead instead of seven.

How could that be? How could a brain so ravaged by disease still be functioning at such a high level? Had something shielded the brain of the chess-playing professor? Was he, like Sister Bernadette, an escapee?

Who Escapes and How?

For many years, scientists have puzzled over why some people seem to withstand brain injury better than others or why two people can have strokes of the same severity and yet one suffers severe impairment and the other recovers.

The differences have been particularly perplexing to neuroscientists because most believed that healthy brains, aside from a few IQ points here and there, were pretty much the same. After about age three, according to long-held scientific thinking, a window of opportunity began to close. Sure, we could polish our French, but the basic structure of the brain was thought to be largely set. And in many ways, that view made sense. Unlike other cells in the body, brain cells don’t divide, so the same neurons stick with us for as long we stick around. With age, some brain cells die off, but it was thought that they were not replaced, leaving our brains to accumulate all the junk and insults thrown their way. Indeed, major changes were considered not only impossible but, if they did take place, mostly bad.

But that view has changed now, too. Even the most conservative of neuroscientists agree that brains can be tinkered with, perhaps even vastly improved, on their most basic synaptic level throughout our lives.

And the very fabric of our daily lives—how we spend our work-days and even our vacations—may influence how we respond to disease, brain injury, or even the more nuanced shifts that come with age.

This is the fundamental idea behind what’s now called “cognitive reserve,” that some brains have—or can develop—a reservoir of strength that, when the going gets rough, offers protection, perhaps much like the brains of Sister Bernadette or the Chess Player. It’s not that those with cognitive reserve are smarter in the conventional sense. Rather, they seem to have an emergency stash of brainpower—perhaps stronger, more resilient, or more efficient brain connections or repair systems that can be called up when necessary. Certain brains may develop a sort of mental padding that allows them to tolerate more damage.

“When we did the autopsy [on the Chess Player] it was amazing that with such a relatively mild level of apparent dysfunction, he had such widespread changes [in his brain],” said Fox when I spoke with him about his own study of the Chess Player.

But if it exists, what exactly is this reserve? Can you see it? Touch it? Can you, if you want to, get more of it?

The story of cognitive reserve is still being written. It is also one of the most encouraging stories ever to be told about the brain—certainly the best news yet for the middle-aged brain. And it’s a story that began not that long ago.

In the early 1980s, Robert Katzman was living in Rye, New York, working as the chairman of neurology at Albert Einstein College of Medicine in New York. In his job, he saw hundreds of patients suffering from dementia, but there was little he could do. At that time—as now—very little was known about Alzheimer’s disease.

So Katzman decided to dig deeper. Scientists knew that those who died with Alzheimer’s usually had plaques and tangles of fibers in their brains, but the relationship was murky. Did more tangles equal more disease? Hoping to clarify at least this aspect, Katzman began a study of a group of elderly people living in a Manhattan nursing home. His initial aim was simply to replicate an earlier finding suggesting that the level of plaques and tangles determined the severity of the dementia.

And, in fact, Dr. Katzman found exactly that. In his 1988 study of 137 nursing home residents whose brains he dissected after their deaths, he saw a clear relationship between the number of tangles and mental decline.

But Dr. Katzman also found something else. In what he called Group A, there were some patients who did not fit the pattern at all. The ten people in this group all had brains full of tangles. But, as was discovered later with people like Sister Bernadette and the Chess Player, they also had been functioning at a high cognitive level up until the very end. Lots of tangles, but mentally first-rate.

In the New York nursing home, Dr. Katzman had found the first documented set of escapees.

When I spoke with Dr. Katzman he was eighty-two years old and long retired, a professor emeritus of neuroscience at the University of California at San Diego. Still mentally alert, he easily recalled his reaction to his own escapee finding. “It was a surprise; we only set out to replicate the other studies,” he said. “And then we found this. It was new, very new.” (Dr. Katzman died in September 2008.)

As he wrote in February 1988:

Our study does provide remarkable findings in regard to Group A, subjects with preserved mental status but definite histological changes of the Alzheimer type. These nondemented subjects with Alzheimer’s changes were functionally and cognitively as intact as those in the control group, the nondemented subjects who were free of histological markers or brain pathology. . . . It can be concluded therefore that there is a group of elderly with preserved mental status and Alzheimer changes.

Knowing that most new and unconventional ideas do not always find the warmest of receptions, I asked Dr. Katzman if he recalled the response of other scientists at the time. “Was it controversial? Oh, yes,” he said, laughing. “I mean, it was new, so automatically it was controversial. But I know I believed it then and I believe it now,” he added bluntly. “We had the data.”

As it happened, he also had something more. Katzman found that the Group A brains were not only somehow protected but also bigger. As he wrote at the time:

In regard to the number of large neurons in the three regions of the cortex measured, these nursing-home residents surpassed the subjects in the control group as well as the demented patients with Alzheimer’s disease . . . the brain weights in Group A were greater than in the other groups, suggesting that there has been less atrophy than normally found in the very elderly or that this group of patients started with more neurons and larger brains and thus had greater reserve.

Wondering what it all might mean, he went on:

This implies that patients in Group A had incipient Alzheimer’s Disease but did not show it clinically because of this greater reserve. . . . [Those who have] retained intact pyramidal neurons and whose brains are heavier than age-matched normal subjects . . . these people may have escaped the shrinkage of large neurons that accompanies normal aging and the loss of large neurons that usually occurs in Alzheimer’s Disease so mental status is preserved in spite of beginning Alzheimer changes. Alternately these people might have started with a larger brain and more large neurons and thus might be said to have had a greater reserve.

With that, the idea of cognitive reserve was officially born. It was also linked, from the start, to bigger brains. Indeed, a few years later, similar observations were made by a technician helping to dissect Sister Bernadette’s brain: “Look at the initial MRI scan,” the technician said. “It shows an unusual amount of gray matter.” As Dr. Snowdon elaborated in his book: “As it turns out Sister Bernadette had more gray matter . . . than 90 percent of the other sisters studied.”

The Education Connection

So it’s possible to be an escapee, to both have tangled brains and still teach a class of ninth graders? But to do that, do you also have to have a giant brain? For those of us with smallish heads, this is a less than happy thought.

Luckily, science didn’t stop there. As the research into cognitive reserve has matured, it has become increasingly (and happily) apparent that there is more to all this than buff and brawn. While there is a correlation between brain size and reserve, cognitive reserve turns out to be much more complex—and possibly within reach—than that.

Indeed, one of the most prominent producers of this extra brainpower turns out to be something that would make your first-grade teacher proud: education. Just as those with more education seem to be better able to call on more parts of their brains when needed, education also seems to offer a kind of overall protection, at least against the outward manifestations of disease.

“Education changes the brain; that is now clear,” said Dr. Katzman when I spoke with him about where we are now with cognitive reserve. “I don’t think we know exactly how, but it changes the brain.”

In recent years, studies have found an indelible line between education levels, or, in the case of those with no access to formal education, literacy levels—and how well the brain ages. This is not a thought that comes completely out of the blue. For many years, education has been tied to living longer in general. The reasons are still being debated, but the idea remains steadfast and serious. As my colleague Gina Kolata wrote in a newspaper series on aging recently, “The one social factor that researchers agree is consistently linked to longer lives in every country where it has been studied is education. It is more important than race; it obliterates any effects of income,” adding that education may “somehow teach people to delay gratification,” a habit that might mean you giving up that cookie or cigarette and instead taking a walk.

Still, tying education levels specifically to brain aging has been more controversial and much more complicated. Some of the initial evidence came from the Nun Study, whose first results showed that those who had higher education levels aged more independently, and were able to bathe, eat, and dress themselves considerably longer than their counterparts with less education.

That tantalizing finding was small, however, and even David Snowdon of the Nun Study concedes that when he presented it at a scientific conference in 1988 the reaction was far from overwhelming, saying he’d had “a better audience for my 4-H project on chickens at the San Bernardino County Fair.”

Then Katzman found it, too. In one of the first large epidemiological studies in China, among five thousand people living in Shanghai in the late 1980s, Katzman found that those with no education had twice the risk of developing dementia than those who had attended middle school or even elementary school. Similar results were later found in population surveys of dementia rates in France, Italy, Sweden, and Israel.

“Alzheimer’s disease is a democratic process,” Katzman wrote, summing up his findings later. “Physicians and psychologists, chess masters and physicists, mathematicians and musicians may become victims of this disorder. . . . Yet a number of recent community studies report that individuals with a lack of education or low education are more likely to develop dementia and Alzheimer’s (AD). This . . . has profound social and biological as well as medical implications.”

Reserve and Respectability

Despite such findings, however, cognitive reserve has been battling an uphill fight for respectability. Doubts and disagreements persist. No one has suggested—or ever found—that education in any way prevents you from getting plaques and tangles or becoming demented. Going to school or becoming self-educated does not eliminate pathology. But beyond that idea, there has been consensus on little else.

And the whole concept, from the start, has had a serious chicken-and-egg problem. Was it simply that those with better brains sought more education or read more and then developed even bigger and better brains as a result? Were those who were inclined to become more educated simply the people who had better nutrition while young or had lives that were generally more protected from toxins that could harm the brain?

Many did not swallow the idea of brain reserve at all. One of these people was Yaakov Stern, a neuroscientist at Columbia College of Physicians and Surgeons. Fresh out of graduate school and working in Manhattan in the late 1980s, Stern had heard stories about cognitive reserve, or backup brainpower, an idea, he says, that was “being bandied about.” But he, like many others at the time, thought it was simply a matter of diagnosis. He believed that those who were more educated were simply better at doing the cognitive tests and were, therefore, less likely to be diagnosed as demented. “I thought it was diagnosis bias,” Stern told me.

As his career progressed, Stern found himself with a good position and adequate funding and he decided to take a serious look at the idea of cognitive reserve.

Interestingly, he, too, focused on a group of elderly living in Manhattan. His group was not living in nursing homes, however, and had a wide range of education levels, varied occupations, and was ethnically diverse as well. Because of his concerns about diagnosis, Stern was as careful as he could be to make sure that although the participants had varying levels of education, they were nevertheless at the same level of cognitive abilities when the study began. He also screened for signs of tiny strokes or vascular problems. Then he followed the group for four years to see what would happen.

And there it was again. Stern and his colleagues found that the better educated in the group were much less likely to show outward signs of dementia. To add a new wrinkle, he also found that those with more complex occupations, which usually meant dealing with human beings rather than working with repetitive machines such as on an assembly line, were also much less likely to become demented. In 1994, he published his study in the prominent Journal of the American Medical Association.

“We found that those with less than eight years of education were twice as likely to become demented and those who had lower education and lower-level occupations were three times as likely,” Stern said.

The finding was, again, surprising, in particular to the skeptical Stern. What was important was that in this study all the participants were at the same place to begin with in terms of mental abilities and general health. The only way they differed was in their level of education. It was also important because it followed the group going forward, with no idea what the outcome would be. Indeed, the results were so striking that Stern went full-tilt to the other side and is now a true champion of the idea of cognitive reserve.

To fully convince himself, though, Stern set out to examine this reserve from every angle he could think of. He and his colleagues found that among those with the same outward signs of dementia, those who were better educated also had the lowest levels of cerebral blood flow, a sign of a higher level of pathology. In other words, again, the more highly educated had a worse physical condition inside their brains, but something was shielding them from the full force of their dementia. Like the nun and the Chess Player, something was helping them tolerate the would-be effects of the disease better.

In two other revealing studies, Stern and his team found that demented patients who had higher levels of education or occupation declined and died faster after being diagnosed. While on the surface that seems counterintuitive, it fits perfectly with the theory of cognitive reserve. It suggests that those who can call on more brainpower can hold back the outward signs of the disease. Then, by the time the disease becomes outwardly evident, its effects are much further along in the brain and those patients both get worse and die faster. These people, more escapees, as Stern says, “have less time to live with the effects of the disease and that seems like a good thing.” Better to be an eighty-four-year-old woman who has had no apparent problems and declines quickly and dies than one who spends years with feeble abilities.

Still, many researchers remained unconvinced and confused. After his first study was published, Stern got a call from a woman whose husband, a Nobel Prize winner, was suffering from a terrible case of Alzheimer’s. “She said, ‘What the hell are you talking about,’ ” said Stern.

Even though no one was suggesting—or says now—that education guarantees protection from dementia, the idea that something as amorphous as education could buffer the brain from the actual physical assault of a serious illness was a hard sell.

“We just didn’t think the brain worked that way,” said Stern.

But increasingly, it seems it does. Other solid studies, such as the Rush Religious Orders Study (more nuns, as well as priests) in 2004, also revealed that for a given level of severity, the more educated, on autopsy, had more tangles and plaques. Again, this suggested that those who had more education were protected longer from the most severe impact of the disease.

That same group found, too, that it was not just the level of education that was connected to the risk of dementia but also “cognitive-stimulating activities.” In a landmark study that helped boost the crossword puzzle industry, the Rush group found that over a five-year period, those who had done more to activate their neurons were about half as likely to develop Alzheimer’s. Stimulating activities were defined as those in which “seeking or processing information” was central and something you could do by yourself (to factor out the impact on socialization, which can also be hugely beneficial to the brain). That meant playing bridge was out, but reading magazines or newspapers, going to the library, doing word games, taking music lessons, or learning a foreign language were all counted.

A researcher in Stern’s lab at Columbia also added more solid evidence. In a study of 1,772 nondemented adults, Nick Scarmeas found that even those with a higher level of “leisure activities,” including walking, visiting with friends, or reading, had a 38 percent lower risk of developing dementia than those who did those things less often. And the risk of dementia decreased by 12 percent for each additional activity added, a finding that held up no matter what level of occupation or education.

Of course, it’s still very much possible that those who fill their lives with concerts and Chinese lessons might simply be better off, brain-wise, to begin with. But the most rigorous studies have done all they can to ensure that all participants are at the same general cognitive level from the start. It’s true, too, that some who do poorly may have early, undetectable stirrings of dementia or vascular disease. But as Stern’s colleague Nick Scarmeas sums up in a book on the latest research on cognitive reserve, edited by Stern: “Overall, the accumulated data seem to make a case for a protective effect of physical, intellectual and social activities for cognitive decline and dementia.”

Most of the recent research has looked at the relationship of cognitive reserve to dementia because, as a slowly progressing disease, dementia is easier to measure. Still more controversial has been the idea, as mentioned by Scarmeas and many others, that this mental cushioning could also soften the less forceful assaults of normal aging.

But in just the last few years there has been a shift. Many now believe this extra brain reserve is real. And it appears that the way we live our lives can have a very real impact on the overall power, strength, and staying power of our brains.

“Cognitive reserve is a very powerful idea,” says Stern. “But it is also a simple one. The fact is that there is not a linear relationship between pathology in the brain and clinical manifestation of that. Something is mediating and some do better than others. And this is not specific to even aging or Alzheimer’s. Those are good places to see it. The evidence is out there.”

As the research into cognitive reserve has exploded, its effects can be seen in wider and wider areas. In particular, researchers now want to know what it means to people who are hitting middle age and beyond. Do we have to start building this backup brainpower as babies? In the womb? Or can we still grab a little if we tackle it when we are past fifty? How about sixty?

The most recent studies suggest that brain reserve can be built anytime in our lives. One long-term study found that those with high socioeconomic status and fully engaged in their environment had the least intellectual decline during a fourteen-year period (widowed women who had never been in the workforce and who had a disengaged or lonely lifestyle did the worst). Another study included in the Scarmeas and Stern review—of World War II veterans tested twice over forty years—found that participating in intellectual activities was related to intellectual performance later in life. Similarly, a well-known British study—a long-term look at people in England, Scotland, and Wales born right after World War II—found that social class, occupation, and education at age twenty-six helped shape cognitive ability at age fifty-three.

More recently, in 2007, a study of workers at a lead-smelting plant found that among adult men with the same blood-lead levels, a result of exposure to heavy metals known to cause neural damage, those with the highest reading scores, while not protected from declines in hand-eye coordination, were somehow shielded in cognitive areas. The men in the group of better readers performed 2.5 times as well on tests of memory, attention, and concentration tasks not necessarily related to reading. The study’s author, Margit L. Bleecker, a neurologist at the Center for Occupational and Environmental Neurology in Baltimore, said she now is convinced that “the brain is like a muscle” and can be pumped up at any age. “Those who are cognitively more active, exercise more, and are more socially connected have more cognitive reserve,” Bleecker says.

Certainly early development of the brain is key and head injuries along the way don’t help, but research increasingly finds that reserve can be added at middle age and beyond. In a Scottish mental-health survey, children born in 1921 first had their IQ tested at age eleven and then at age eighty. While IQ at age eleven was a decent predictor of how well a person would do later on—and IQ is partially inherited—there was clear evidence that we’re not necessarily stuck with what we are born with. Some in that group were able to push their scores up significantly. Something was changing their brains for the better—even well past childhood.

Granted, there are still disagreements and doubts out there. Even Nick Fox in London, who reported on the case of the Chess Player, believes that cognitive reserve has become such a hot topic that all sorts of grand and largely unsubstantiated claims are now being made in its name. Even with the Chess Player, he says, the question remains: Did he withstand the assault of Alzheimer’s for so long because of “something he did” in his life—that is, read, play chess, or become highly educated—or because that’s just how his “high functioning brain was”?

But most evidence now suggests that we can make a difference by what we do; we can boost our reserve, even when older.

“You are not just born with cognitive reserve, and that is the most encouraging piece of this,” Stern said. “It seems to be malleable even in later life. The thing is, we are not sure what is the most protective thing you can do—is it gardening or particle physics? We need to figure that out.”

Perhaps more than anyone else, Stern remains on the trail of cognitive reserve. Step by complicated step, he is trying to find out what it is in our brains that can help—and what we can do to help our brains. Some of Stern’s most recent research, for instance, has confirmed that it is not just complex occupations that make a difference to dementia but occupations that are highly physical.

“I used to have this ivory tower view of cognitive reserve, that it was linked to intellectually stimulating things,” Stern says. “Now I am trying to exercise, to go on the treadmill more.”

Many cognitive reserve studies have looked at large populations, so-called epidemiological studies that seek out correlations or trends. But in the past few years, researchers have also taken a more focused look inside the brain. A study in 2001 by Lawrence Whalley at the University of Aberdeen in Scotland found that among those with the same outward behavioral symptoms of dementia, the most educated also had more decay in their brain’s white matter, that crucial outer coating of brain cells. Again, this was an indication that those with more education were somehow able to cope with more damage and still function.

In one unusual study, researchers found that among a group of people who were depressed and received electric shock therapy known to cause cognitive problems, those who had higher levels of education recovered much faster. And a recent study by Shelli Kesler at Stanford University School of Medicine found that the more educated and those with larger brain volume even had a smaller dip in IQ after traumatic brain injury.

“I’m quite passionate about cognitive reserve,” Kesler told me. “I am definitely a believer. It’s just like an athlete is better at sports and would be more protected from heart disease than someone who is obese.”

Experience Changes Structure

“Cognitive reserve,” Kesler said, “is basically a type of neuroplasticity—we know from repeated animal and human studies that experience can alter our brain function and structure. I think cognitive reserve results from a combination of heredity and life experience. If you have smart parents, you will have a higher reserve—just like the athlete model—some people are just born with greater physical prowess—I’m trying to identify particular genes that might endow people with greater cognitive reserve or increased neuroplasticity.

“But just like an athlete—genetics will only get you so far—training and practice are essential. If you engage actively in mental and physical activities, particularly those that have a graded challenge (get more difficult as you progress), you also can increase cognitive reserve. It’s best to continually increase the challenge or difficulty level to keep on benefiting . . . a variety of mental activities that are new and stimulating will be the most helpful. I think this is one reason why people with higher education levels tend to have higher cognitive reserve—they have had a variety of mental stimulation and tend to seek this out.”

And, she said: “The best news is that neuroplasticity exists across the life span—you’re never too old to improve your brain function.”

Back in New York and now a true believer, too, Yaakov Stern at Columbia University is even trying to create cognitive reserve in his lab.

Much of what matters in the brain as it ages, Stern believes, will depend not on its hardware—how big, how many brain cells, how many branches and connections—but on its software, that is, how a brain operates. He believes that brains may age better if they also have the capacity to compensate, or “switch to plan B,” by using additional or alternate parts to do what they need to do.

This is a version of the two-brain idea. And it means that those who can, or who can learn how to, use more of their brains when they need to will be better off in the long run. These are the lucky escapees, who, Stern says, are “able to summon that compensatory response. They are used to engaging these networks and can do it more easily.”

Another key ingredient may also be basic brain efficiency. In one of his most recent studies, Stern found that, confronted with increasingly difficult problems, those with higher IQs used a smaller percentage of their overall brainpower to get answers. It was as if that group could “accelerate,” or ramp up, their brains with less effort.

Stern firmly believes that we can, by challenging our brains throughout life—perhaps by learning how to use our frontal lobes more efficiently—build up cognitive reserve. He is also trying to figure out if such brain efficiency can be taught to the middle-aged and older brain, when such training might be most beneficial.

“The best way I can explain this is to think of two swimmers,” he told me. “If you take a very good swimmer and ask him to swim a lap and then you have me swim a lap, at the end I will be winded and the good swimmer won’t break a sweat. He is more efficient. Then you ask us both to swim a mile and I won’t be able to do it at all but he will. He is not only more efficient but he has more capacity. Then you take that good swimmer and put a ten-pound weight around his waist; how does he do then?”

The ten-pound weight is middle age, old age, and disease. And the question on the table—one that is being pursued with a passion that would make that old seeker of the Fountain of Youth, Ponce de León, proud—is, how can we, even as we forget where we parked the car, build up reserve and keep our brains swimming?