The Memory Bible

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Preface

    Nearly everyone struggles with some form of memory loss before reaching middle age. Thanks to recently developed brain-imaging and genetic technologies, scientists can now observe the earliest physical indicators of brain aging in people as young as twenty-five. Tiny plaques and tangles that develop and grow ever denser in our brains often begin accumulating decades before any middle-age forgetfulness sets in. A minute spot of plaque on a 30-year-old brain could possibly indicate Alzheimer’s disease forty years from now, just as a tiny little snag of the dentist’s probe can mean a cavity in the making.

But we need not despair. Misplacing your keys a couple of times doesn’t mean you should start labeling your cabinets. Memory loss is not an inevitable consequence of aging. Our brains can fight back, and The Memory Bible will give you the tools. We can improve our memory performance immediately and stave off, possibly even prevent, future memory decline. The sooner all of us begin our memory program, the sooner we will be on the path to keeping our brains young and healthy for the rest of our lives.

Gary Small, M.D.
Los Angeles, California, May 2002

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Chapter One
You Have More Control Than You Think

Imagine struggling your way out the glass doors of a crowded mall in late December, loaded with shopping bags, packages, and presents. Your head is pounding and your feet hate you and the shoes you walked in on. You’d die of starvation this second if you weren’t already dying of thirst. You manage to pull out your car keys and glance up at the humongous, jam-packed parking structure when it hits you—you’ve forgotten where you parked.

Could never happen to you, you say? Ever forgotten your purse, wallet, file, or phone at home, only to remember it while caught in rush hour traffic? Maybe you’ve struggled to remember the name of a movie you saw last night or that new neighbor you just met, not five minutes ago. Ring a bell?

Most of us laugh off these so-called middle-aged pauses, considering them just another normal annoyance of aging, not a true memory problem, and certainly not a sign of Alzheimer’s disease—not at “our age.” I hate to pop another “I could party all night and still get to work on time if I wanted to” baby-boomer bubble, but it’s time for us all to wake up—we are all one day closer to Alzheimer’s disease.

It Is Never Too Late or Too Early to Fight Brain Aging

Just as all of us inevitably get older, recent convincing scientific evidence shows that Alzheimer’s disease is not simply an illness that some old people get. Alzheimer’s disease or a related dementia may well be everybody’s end result of brain aging—and it begins forming in our brains much earlier than anyone previously imagined, even in our twenties.

The subtle, gradual aging of the brain starts as tiny plaques and tangles that begin accumulating there, decades before a doctor can recognize any symptoms of the disease. In fact, these plaques and tangles begin forming so early in our adult lives that subtle memory and language changes go unnoticed and ignored for many years. Nonetheless, these minuscule spots of plaque in our otherwise healthy brains are the first signs of brain aging, and they will increase insidiously if we do nothing about them.

When I speak on this subject I am often asked: Will my brain already be irreversibly damaged by the time I reach middle age? Is it too late for me to try to head off this inevitable process? Is it too soon for me to start? Is my memory ability destined to decline no matter what I try to do about it?

My answer to these questions is no. It is never too late or too early to start beating the brain-aging game. Even if one day research finds a way to restore already lost brain cells, scientists agree that preventing the loss of memory will always be easier than restoring it. The sooner we rise to the challenge, the sooner we can intervene in the battle, like little neuron-gladiators, and, with luck, do so while our forgetfulness is minimal or even imperceptible.

Our Brains Aren’t Getting Any Younger, but They Can Get Better

One of the biggest obstacles to starting a program to improve memory performance and protect our brains from Alzheimer’s disease is denial that one’s brain, as well as one’s body, is aging. Many people struggle to accept the physical changes that come with passing years, yet coming to terms with mental changes is often an even greater challenge.

Beginning a program to improve memory and slow down brain aging requires accepting that we need such a program. A better understanding of what actually happens to our memory abilities and our brains as we age will help us keep our brains at their peak performance.

What Is Memory?

Normal memory performance involves both learning and recall (Figure 1.1) and requires intact functioning of several regions of the brain and the brain cells, or neurons, within them. We generally think of memory as an abstract concept—a thought, image, sensation, or feeling that is stored somewhere in our brain’s filing cabinet, ready to be pulled out at will. However, because our brains are comprised of nerve cells, chemicals, and electrical impulses, our memories are actually encoded, stored, and retrieved as a result of minuscule chemical and electrical interactions.

Each nerve cell in the brain has a single axon that acts like a telephone line, conducting nerve impulses toward neighboring neurons. The friendly neuron next door receives the countless assortment of electrical impulses sent to it daily, through its dendrites—bunches of thin filaments extending out like little antennae, receiving and sending information. But the new info is not home free yet.

To allow all of our brain’s neurons to communicate with the others, the axons and dendrites form thousands of branches, and each branch ends in a synapse, a specialized contact point or receptor that recognizes only extremely specific information being passed between neurons. Each neuron has approximately 100,000 synapses.

Electrical nerve impulses containing the new information, retrieved memories, or relayed messages shoot down the neuron’s axon and slip through one of its skinny dendrites into a hyper-specific synapse, where a packet of chemicals, known as neurotransmitters, gets released. These neurotransmitters are the “carrier pigeons” that travel the minuscule space from one synapse to the next. Upon arrival, the correct chemical neurotransmitter binds with its corresponding receiver, and voilà! The message is received. In this way, thoughts and ideas are conveyed, information is learned, and memories are retrieved, all of which cause us to do, think, or act in different ways.

In any waking situation, our senses are bombarded by sights, sounds, and other stimuli that pass through our immediate memory and move into a holding area known as short-term memory. We usually lose most of these fleeting sensations in milliseconds, and of the few retained in our short-term memory, only a small percentage ever make it into long-term memory storage.

An essential key to retaining information longer is to organize and rehearse it, thus actively working it into our long-term memory. Some people require great effort to develop these skills, while others are born with a knack for memory techniques and “tricks” to reinforce new information and make it stick. They are often considered to have “photographic memories”—a myth we shall discuss later.

Once information is lodged in our long-term memory, it becomes relatively permanent and can be recalled years later—as long as our brains remain healthy. While short-term memory has only limited capacity, long-term memory has the potential to store tremendous amounts of information. Retrieving this information later, or pulling it out of memory storage, is known as recall. Even patients with advanced Alzheimer’s disease, who may have difficulty remembering their morning meal, have been known to recall long-ago events, such as their first date with a sweetheart, in vivid detail.

Figure 1.1

Recently, scientists have learned how the brain converts short-term memories into permanent ones at the molecular and cellular level. A specific protein must be present in the brain’s cerebral cortex, the outer rim of the brain containing gray matter, for the process to succeed.

The brain’s hippocampus, a seahorse-shaped brain structure located in the temporal lobe of the brain (near the temples), stores information on a temporary basis—much like a computer holds data in its random access memory. When the brain converts the information into permanent memory, similar to writing data to a computer’s hard disk, the hippocampus interacts with the cerebral cortex to complete the task.

Sex, Style, and Emotion

People vary in their learning styles. Long before I became interested in memory research, I instinctively relied upon my visual learning strengths in everyday life. I had always found it easier to remember someone’s last name if I spelled it out in my mind’s eye. Auditory learners retain information best if they hear it, while visual learners remember best when they actually see the information.

Memory and other cognitive skills often vary according to gender: women tend to have better verbal and language abilities, while men generally have the edge in spatial and mathematical abilities. However, when I mentioned this to my wife, she nearly managed to talk me out of it.

Various other factors influence our memory abilities. Emotional states have a major impact on the efficiency and the quality of memories. Ask yourself where you were and what you were doing when President Kennedy was shot. (Or John Lennon, for you youngsters.) All of us who were around certainly know the details of where we were, whom we were with, and how we felt, yet I doubt that we can remember similar details of events the week before. Information that is emotionally charged has a distinct quality and is easier to learn and recall. The memory of your first crush in second grade probably remains distinct. Many of us can recall details of that boy or girl we barely knew decades ago. By contrast, when we are experiencing feelings of depression and prolonged anxiety or stress, we become distracted and our memory abilities diminish.

Memory Changes with Age

Although we all experience some forgetfulness as we age, we each differ in our degree of memory change, our concern about it, and the steps we take to cope. By the time we reach our thirties and forties, so-called “normal” memory complaints become more common.

Middle-aged and older people most often notice difficulties with:

• People’s names

• Important dates

• Location of household objects

• Recent and past events

• Meetings and appointments

• Recalling information

Age-related memory loss more often involves recent memories rather than distant, past ones. We might forget what movie we saw last weekend yet still recall our ninth-grade homeroom teacher’s name. Neuropsychological evidence shows that age tends to slow down our learning and recall skills, perhaps making it more difficult for older adults to learn a foreign language or scientific discourse. (I wouldn’t want to try to pass advanced calculus again at 50.)

Older people have greater difficulty multitasking and our reaction time can slow down as we age, which can affect our daily activities. Many older drivers compensate by driving more slowly, which can be a hazard in itself. Memory training (Chapters 3 and 6) and a program of mental aerobics (Chapter 5) can help lessen the impact of many of these age-related changes.

In the early 1990s, memory experts defined diagnostic criteria for the memory changes that accompany normal aging. When someone over 50 had a memory impairment demonstrated by at least one standard memory test, along with a subjective awareness of memory changes, they called the phenomenon age-associated memory impairment. These experts estimated that 40 percent of all people are affected by this condition upon reaching their fifties, 50 percent in their sixties, and over 70 percent by age 70 and older.

Although there is debate over whether or not age-associated memory impairment will or will not progress and at what rate, it is likely that the condition precedes other, more severe memory declines.

Without some form of intervention, whether it’s implementing strategies to keep your brain young and healthy or, if needed, medical evaluation and treatment, people who ignore their age-associated memory impairment may eventually develop mild cognitive impairment. An estimated 10 million Americans over age 65 suffer from this more severe memory decline, and this condition has a 10 to 15 percent chance of developing into Alzheimer’s disease with each year that passes.

Figure 1.2

These diagnostic categories—age-associated memory impairment, mild cognitive impairment, and Alzheimer’s disease—are basically categories of convenience, allowing doctors and scientists to better understand our aging brains and test treatments to alleviate memory decline (Figure 1.2). In reality, the changes in our brains and the memory difficulties we experience are continuous, fluid processes beginning remarkably early in our lives. Several recent studies point to just how early.

Language Skills and IQ Tests at 20 Predict Alzheimer’s Disease at 80

Several years ago, Dr. David Snowdon and his associates at the University of Kentucky performed clinical evaluations and standard memory tests on a group of nuns who were aged 70 or older. Each of these participants in what is known as The Nun Study kept diaries when they entered their convents in their early twenties. The scientists had access to these earlier documents and performed a standardized linguistic analysis of these diaries, objectively rating early language ability. The nuns whose youthful writings demonstrated greater idea density and grammatical complexity were much less likely to develop significant memory loss or Alzheimer’s disease decades later, in their seventies.

The study’s conclusion, that language ability at age 20 may predict whether or not someone will get Alzheimer’s disease fifty years down the road, stirred debate over whether learning and educational enrichment protected the brain from decline over time, the “use it or lose it” theory.

More recently, Scottish psychiatrist Dr. L. J. Whalley and his colleagues studied intelligence test records to determine if a person’s IQ early in life predicted Alzheimer’s disease up to fifty years later. This group found that people with lower intelligence test scores in childhood had a greater risk for the late-onset form of Alzheimer’s disease that begins after age 65.

Dr. Whalley offered several explanations for the observation, including the possibility that people with lower intelligence in childhood might engage in behaviors later in life that put them in greater danger of getting Alzheimer’s disease. They may eat a less healthy diet, avoid exercise, or smoke. Alternatively, the low IQ score may reflect the early signs of the disease itself deteriorating the brain subtly early in life. This could then influence school performance and further educational pursuit. Having less education may not be the cause but may actually be the result of the early stages of brain aging.

The Incredible Shrinking Brain: Beware of Plaques and Tangles

As our brains age, the synapses, or connections between neurons, begin to function less efficiently. Messages firing from one region of the brain to another may get scrambled, and crucial communication from one part of the brain to the other may break down. One area of your brain may tell you to walk into the kitchen and open the refrigerator, but then you just stand there. Unfortunately, the part of the brain that should have told you to reach in and get a soda because you’re thirsty didn’t receive the message.

Data show that as our neurons age and die, the actual overall sizes of our brains shrink or atrophy. Also, our aging brains accumulate lesions known as amyloid plaques and neurofibrillary tangles. These collections of decayed material result from cell death and degeneration of brain tissue, particularly in areas involved in memory: the temporal (under the temples), parietal (above and behind the temples), and frontal (near the forehead) regions of the cerebral cortex, the outer layer of brain cells. A healthy, plump brain containing only sparse plaques and tangles gradually shrinks to an atrophied Alzheimer’s brain riddled with plaques and tangles.

Historically, a definitive diagnosis of Alzheimer’s disease could only be made at autopsy. The pathologist would count up the number of plaques and tangles that had accumulated in these key brain regions, and if their concentration surpassed the defined threshold the patient under examination definitely had Alzheimer’s disease. Scientists have studied brain autopsies in people who had only mild cognitive impairment rather than Alzheimer’s. They see the same plaques and tangles, in the same brain areas, only in lower concentrations.

These autopsy studies have now been extended to people in their twenties and thirties who had normal memory abilities, and still these brain lesions are seen to be present, albeit in lower concentrations. In every age group, the accumulation pattern is consistent: the lesions start in areas near the temporal lobe and spread to the parietal and frontal regions. Most of us, unless of course we have a genetic risk or some other predisposition, don’t live long enough to reach the plaque-and-tangle threshold defined as full-blown Alzheimer’s disease.

Studies of the annual incidence of Alzheimer’s disease, or the percentage of the population that develops it each year, show that the rate of new Alzheimer’s cases doubles every five years between ages 65 and 90. Scientists suspect that if the current trend toward increased lifespan continues, people may soon be living, on average, well into their eighties and nineties. Unfortunately, the proportion of the population with Alzheimer’s or another dementia will rise correspondingly. In fact, I am convinced that, if we did nothing to prevent brain aging, the prevalence of Alzheimer’s disease would approach 100 percent if we all lived to be age 110 (Figure 1.3).

Figure 1.3

The rate at which our brains age varies according to our individual genetic predisposition, lifestyle choices, and our lifelong environmental exposures. Also, the use of new technological advances allows us to recognize the earliest signs of brain aging without having to dig up our old high school diaries or agree to a brain biopsy.

Big Heads Don’t Make Men Smarter

Subtle and not so subtle differences between women and men likely influence memory abilities and brain health as they age. Women have smaller brains than men. (It’s just a fact, don’t shoot the messenger.) The average brain weight for an adult man is just over three pounds, while the typical woman’s brain is a bit over two and two-thirds pounds. Neuroscientists have found that generally the bigger the brain, the smarter the animal, but that rule does seem to break down with the human brain—a point my better half will argue adamantly.

Recent studies of brain structure and function have shown that although women have smaller brains, their brains are more efficient, thus leveling the overall intellectual abilities between women and men.

Dr. Ruben Gur and his colleagues at the University of Pennsylvania looked at the amount of gray matter in the brain—the outer part containing cell bodies that allow us to think—and found that, on average, 55 percent of a woman’s brain contains gray matter, compared with only 50 percent of a man’s brain. This may explain why women score higher in language and verbal ability tests than men. By contrast, men have a higher proportion of white matter, which transfers information from distant regions, perhaps a key to their greater visual-spatial abilities.

Granny’s Not Sick, She’s Just Old and Getting Senile

When I was growing up, Billy J., the kid across the street, had his grandmother living with them. Every once in a while, she would wander out of the house, and Billy’s parents would have to go looking for her with the car. One time they didn’t find her for an entire day. When my father, a physician, asked Billy’s dad if he could recommend a doctor to help her, Billy’s dad laughed and said, “Granny’s not sick, she’s just old and senile.”

Early in my clinical and research training in geriatric psychiatry and Alzheimer’s disease, Dr. Lissy Jarvik stressed that senility was not a normal part of aging but instead a disease. This was an important message at the time because most experts were ignoring the problems of aging, even the most common ones: memory loss and dementia. By emphasizing the disease factor, investigators began to approach the problem as an abnormality that required accurate diagnosis and specific treatment.

In fact, this has long been the basic approach of western medicine, to diagnose a disease and look for the best treatment and cure. It is still a challenge to initiate proactive, preventive approaches to diseases. We all want a quick cure, a magic pill to alleviate our problems when they occur. Patients and physicians are reluctant to “fix it if it ain’t broke.” But when it comes to an aging brain, what we don’t know will hurt us.