Think Smart: A Neuroscientist's Prescription for Improving Your Brain's Performance (24 page)

In an attempt to explain such unexpected findings the pathologists speculated, I believe correctly, that education in general makes for a more efficient use of brain networks, resulting in a greater ability to withstand the so far incompletely identified insults to the brain responsible for Alzheimer’s dementia. The pathologists even came up with a term for it:
cognitive reserve
(sometimes called cerebral reserve).

As a useful analogy, think of cognitive reserve in monetary terms. The more money you have, the easier it is for you to manage financial downturns; compared with your less affluent neighbor, you will have to lose more money before you’re financially wiped out. That analogy also helps explain a companion observation about education and Alzheimer’s disease (or any other dementia, for that matter). When the person with greater education develops dementia, the disease has reached a more advanced state than would ordinarily bring on symptoms in a person with less education. What’s more, death occurs soon after symptoms first appear. It’s speculated that in such instances the afflicted person’s cognitive reserve, initially higher than the average person’s, finally ran out.

According to the work of Yaakov Stern of the Cognitive Neuroscience Division of the Taub Institute at Columbia University in New York City, greater cognitive reserve is linked with enhanced activation of a brain network in the frontal lobes. In both younger and older subjects, the higher their IQ scores, the better they did on memory tests and the greater the activation of their frontal lobe network. And since higher IQ scores generally correlate with more years of education, Stern’s findings provide yet another reason for building up cognitive reserve by staying in school longer.

While the emphasis on formal education as an explanation for cognitive reserve seems to make intuitive sense, I think it’s overly simplistic. If you think carefully about the cerebral reserve hypothesis, why would greater cognitive reserve necessarily be linked with
formal
education? It’s just as likely that those same brain networks that can be brought to maximum efficiency by formal education can also be enhanced by informal education—what was once referred to as the school of hard knocks, which confers advanced degrees in street smarts.

For instance, an eighty-two-year-old patient of mine who quit school after the eighth grade earned millions of dollars over a lifetime of shrewd real estate investing. Or consider the late humorist Art Buchwald, who ranks close to the top of my personal list of the smartest people I’ve known. His formal education? Two years of college. Such exceptions to the education-cognitive reserve rule are rarely cited when learned professors publish papers lauding the brain benefits of higher education. No mystery here: the professors carrying out the studies possess doctoral and other advanced degrees and consequently are only too ready to equate intellectual abilities and a highly functioning brain with formal education. After years of associating with others with similar educations they are more than slightly uncomfortable with the thought that perhaps the mechanic who services their Lexus may be smarter than they are.

“Cognitive reserve is not something you were born with,” Yaakov Stern observes. “It’s something that changes and can be increased over time. Even something as simple as keeping up a regular reading schedule can increase cognitive reserve and reduce your chances of getting Alzheimer’s disease.”

Increase your cognitive reserve by engaging regularly in some form of cognitive training. According to Michael Marsiske, a principal investigator of a study funded by the National Institutes of Health that examined the effect of cognitive training on everyday functioning, mental decline among middle-age and older adults can be prevented by as little as ten sessions of mental exercises aimed at boosting reasoning skills, memory, and rapid mental processing.

When discussing cognitive training, Marsiske, a youngish-appearing forty-one-year-old neuroscientist, speaks volubly and with an infectious enthusiasm on his favorite topic: how to improve mental performance in middle to late adulthood through mental exercises. He described for me the mental exercise program he has developed as a result of his research:

For
memory training
he suggests forming visual images and mental associations as a means of recalling words and verbal narratives such as stories. This is similar to the methods described in Part Three. In order to develop
reasoning training,
he proposes such exercises as learning to discern the pattern in a letter or word series (e.g.,
acegi. . .
) and then identifying the next item in the series (
k
—every other letter is omitted).
Speed of processing training
involves visual searching combined with divided attention: identifying an object on a computer screen at increasingly brief exposure times while dividing one’s attention between two separate search tasks. For instance, judging which configuration of objects (two cars, two trucks, a car and a truck) appears in the center of a computer screen while simultaneously identifying the location of another target on the periphery of the screen.

Marsiske’s results with his research subjects turned out to be even more impressive than he expected. Ten exercise sessions, each lasting sixty to seventy-five minutes, were all that his subjects needed to attain remarkable improvements measurable up to five years later, compared with people who didn’t participate in the exercises. The memory-exercise performers did 75 percent better when memory-tested; reasoning-test participants did 40 percent better on reasoning exercises; and the speed-training veterans responded 300 percent faster. Taken together, a short investment in time and energy aimed at improving three areas of mental functioning led to sustained cognitive improvements and the prevention of age-associated declines in mental function.

What makes Marsiske’s findings even more impressive was the age of the typical participant in the studies: an average of seventy-three years with a range extending from sixty-five to the early nineties. “But these findings apply to people in their fifties or even younger,” he says. “This kind of training works no matter what your age. And the mental skills acquired earlier in life persist for many years.”

Since building cognitive reserve is a lifetime enterprise, the earlier you start accumulating it, the better. That’s because neuroscientists aren’t certain when Alzheimer’s disease actually starts. For instance, children age seven to ten years who possess a gene (ApoE4) known to increase the risk of Alzheimer’s disease show signs of reduced cognitive performance compared with children possessing other forms of the gene.

“This suggests there are cognitive differences very early in life,” notes Jacob Raber, the Portland, Oregon, researcher who carried out the study. But, as Raber readily admitted when I asked him, ApoE4 isn’t a thoroughly reliable marker for Alzheimer’s disease even among aged adults: some older people with that gene show no signs of Alzheimer’s disease either during life or at autopsy. Thus no one would—or should—make predictions that these children are necessarily destined to go on to develop Alzheimer’s disease. And yet Raber’s findings are troubling.

Ronald Reagan provides the most famous contemporary example of the difficulty in pinning down the earliest beginnings of Alzheimer’s.

Did President Reagan’s disease begin after he left office, or earlier? In 1987, the editors of the “Outlook” section of
The Washington Post
asked me to write an article addressing that question. At the time, toward the end of Reagan’s second term, rumors were spreading rapidly in Washington that Reagan was suffering from Alzheimer’s disease—based mostly on the vagueness of many of his responses during press conferences.

After reviewing transcripts and watching videos of Reagan’s speeches and press conferences dating back to his days as governor of California, I concluded in my
Washington Post
article that Reagan showed no evidence of the disease while he was in office. The fact that doctors later diagnosed Reagan as suffering from Alzheimer’s disease makes me less certain of that conclusion today. When I wrote my article, he might well have been showing the earliest signs of the disease. Yet pinning down exactly when President Reagan began showing indisputable signs of Alzheimer’s disease isn’t any easier twenty years later than it was when he was completing his term.

Throughout his adult life Reagan often couldn’t come up with answers when asked specific questions. For instance, on February 5, 1962, Reagan, then fifty-one and president of the Screen Actors Guild, appeared before a Los Angeles federal grand jury called to probe antitrust allegations against MCA, the talent agency that represented Reagan. Throughout his testimony he offered responses as vague as those that would later characterize his news conferences during the later days of his administration. Was he afflicted with the earliest signs of Alzheimer’s disease at fifty-one? Or did he simply possess a poor memory? Or did he do this on purpose?

As with President Reagan, the earliest signs of Alzheimer’s often escape detection and are recognized as harbingers of the illness only after the disease has greatly advanced. Beyond sixty-five, the risk of dementia (largely but not exclusively due to Alzheimer’s disease) doubles every five years. With statistics like these, anything that can be done to lessen the odds of Alzheimer’s disease should be done.

Here are several other suggestions for lessening your risk for Alzheimer’s disease:

Keep working for as long as you can at a challenging job that fully engages all of your talents and abilities.
During your leisure hours follow the same principle: take up bridge, Go, or mahjongg. Get together with skilled Scrabble or poker players. When you’re alone, read or do crossword or sudoku puzzles.

Establish and maintain a network of friends and acquaintances,
since social isolation and the loneliness that usually accompanies it are now recognized as significant hazards to healthy brain function. To get a feeling for how important that is, imagine yourself mentally transported to a deserted island where there is no one to talk to and no means of sharing your experiences. Most people would find such a prospect extremely painful and distressing. That’s because we’re social creatures who have learned over the years that we
need
the presence of other people. Our penal practices provide a perverse recognition of this need: solitary confinement is reserved for those prisoners considered worthy of the harshest punishment. Health statistics also confirm the baleful effect of isolation. Lonely people are more prone to heart attacks, depression, suicide, and an assortment of physical and mental ills.

“I miss having people around me.” “I often feel abandoned and completely alone.” “I miss having a really good friend.” These are some of the feelings expressed by lonely people on a test measuring loneliness. These comments describe an inner experience quite different from depression. A depressed person, typically, tends to socially withdraw; he simply cannot summon the energy needed for the give-and-take of social exchange. Lonely people, in contrast, crave human companionship and welcome any opportunity to mingle.

Recently, researchers have learned that lonely people are not only at greater risk for depression and certain other illnesses, but also more likely to suffer from cognitive problems, including an increased risk for developing Alzheimer’s and other dementias.

According to a 2002 research study of twelve hundred elderly people in Sweden, the incidence of dementia, primarily Alzheimer’s disease, was highest among those seniors with the least social contact. In general, the more socially involved the participants (frequent involvement in group activities such as sports, games, classes), the better they did. But even those with more limited socialization did better than loners, who tended to do things on their own and avoid other people. The Swedish findings were confirmed in 2007 by a study of eight hundred older people in the Chicago area that concentrated on loneliness. It found that lonely people are more than twice as likely to develop Alzheimer’s than people who aren’t lonely. Marriage serves as a protection against loneliness, but regular contact with close friends can be equally effective in combating loneliness. Whether one is married or single, it’s important to counteract feelings of loneliness, since loneliness is a greater risk factor for Alzheimer’s than depression or diminished physical and mental activity.

“Brain health and neural plasticity will be supported by anything that signals the brain that we are still an important member of the community and that adaptation is still required,” according to Louis Cozolino, a psychologist at Pepperdine University in Malibu, California, and author of
The Healthy Aging Brain.

In order to lessen the risk of loneliness-associated cognitive deficits, then, increase the time that you spend every day engaged in activities involving other people. On occasion you may have to force yourself to do this, especially if you tend to be shy or introverted. But as the research mentioned above indicates, you now have an excellent reason for making this effort: optimal brain health requires regular socializing.

In order to nail down the specific benefits of socialization I spoke to Dilip Jeste, director of the Stein Institute for Research on Aging, University of California, San Diego. He told me: “We have found several specific benefits of socialization: lower overall mortality rate, protection against hypertension and other cardiovascular diseases, less depression, higher cognitive performance, and most important, the delayed onset of dementia.”

Think of it this way: The brain is a social organ that operates by the concerted activity of millions of neurons linked together by means of circuits—there is no such thing as a solitary neuron. Similarly, none of us exists in isolation; nor are we capable of optimal cognitive functioning unless—like a neuron within the brain’s circuits—we become part of a wider social network. If you’re experiencing loneliness, consider it your highest priority—for the sake of your brain—to take steps to bring yourself into meaningful social relationships. Join a hiking club, take a cooking class, volunteer at your church, recruit members for a book club—the choice will depend on your background and interests.