The Memory Cure: How to Protect Your Brain Against Memory Loss and Alzheimer's Disease

PERFECT MEMORY FOR LIFE

You probably can picture Neil Armstrong walking on the moon, John F. Kennedy's assassination, and the destruction of the World Trade Center towers on September 11, 2001. No doubt you remember where you were and exactly what you were doing on those days. Clearly, your brain has the capacity to store and recall detailed information from the distant past. What you might not know is that it's possible for you to have this kind of recall as you age: to have a perfect memory for life.

Understanding how your brain and your memory work is a necessary step to learning how to protect and stimulate your brain in order to achieve a lifetime of perfect memory. In this book, we will discuss how your brain and memory work and when they are at risk, and what you can do today that will improve your memory in the decades to come. We'll also explore "normal" memory and how and why it varies from person to person.

How Memory Works

Your memories are a reflection of your whole life. When you remember your child's first smile, you relive the joy you felt during that very special moment. Etched in hundreds of billions of cells in your brain, your memories come to the surface when you hear the voice of an old friend or see a picture of your childhood home. Cells in other parts of your body-such as your skin, stomach, and liver-slough off and get replaced, but for the most part, the cells in your brain are the same ones you were born with. They witness with you all that you experience over decades of your life. These brain cells are what mediate your sense of vision, hearing, and taste, as well as your experiences of joy, frustration, sadness, success, pride, and, of course, your memory. To do this, the cells in different parts of your brain have divided the responsibilities for making new and different forms of memory.

Let's begin our exploration with the three different types of memory and processes that occur in your brain when you encounter something new: long-term memory, short-term memory, and procedural memory.

LONG-TERM MEMORY

There are three stages in making a memory that lasts from hours to decades: acquisition, storage, and retrieval. To remember a name or an event, you first acquire that information in some parts of your brain, and then you store it in other parts. Once stored, you have access to that information and can retrieve it at any time. This process is analogous to operations in a large library. Books are first acquired from various sources, then stored in different places throughout the library. They can be retrieved easily by a call number.

Thanks to sophisticated new brain imaging techniques, as well as years of studies with animals and with patients who have memory problems, brain scientists can now pinpoint where most of the above processes in the brain take place. You acquire information from the world around you-mostly through your eyes and ears-in your hippocampus, and you store them in your cortex. Let's take a closer look by using an event you're likely to remember well.

Try and remember what you were doing on the morning of September 10, 2001. You probably don't remember much. Now think about what you were doing on the morning of September 11, 2001. No doubt you can provide accurate details on where you were, the people you were with, and how you were feeling. As you were watching the news on television with anxiety and stress, the sights of the World Trade Center towers crumbling down and the sounds of sirens in New York streets were pouring into your brain through your eyes and ears. All this information was funneled to your hippocampus, the part of your brain that is critical for making new memories.

In fact, you have one hippocampus on the left side of your brain and one on the right side. Each looks like a small banana and sits near your ears. In the hippocampus, a subset of information-pieces that are relevant to you-gets etched more firmly and is then sent to other parts of your brain for long-term storage. To continue our library metaphor, you can think of the hippocampus as a librarian (in the acquisition section) who throws out the junk mail and keeps the important publications.

The part of your brain that receives the information from the hippocampus is the cortex. We'll discuss this further in the next chapter, but for now, suffice it to say that the cortex is a sheet of cells sitting on top of the brain, and each part of it has a specific function, such as vision, hearing, or smelling. On September 11, the "sight" of the towers crumbling down was shipped for long-term storage to the "vision" parts of your cortex, and the "sound" of sirens was shipped for long-term storage to "hearing" parts of the cortex. Thanks to your hippocampus and cortex, all this information sits vividly in your brain, and you can instantly retrieve it.

In contrast, you forgot the events of September 10 because they were not too crucial to you. Your hippocampus did receive a great deal of information that day, as it does every day, but it was not worthy of long-term storage. On a daily basis, you encounter thousands of pieces of information, but only the pieces that are meaningful and significant are likely to make an impression on your hippocampus and get shifted to other parts of your brain for storage in long-term memory. As you'll see in the Afterword, we'll discuss ways you can heighten your attention and senses in order to memorize things that are not that important but which you'll want to remember anyway, like the names of acquaintances you see once or twice a year.

SHORT-TERM MEMORY

Often, you need to keep some information in your brain for only a few minutes. This is what a waiter does when he takes your lunch order without writing it down and remembers it until he goes to the kitchen. The information about your order reaches his hippocampus but does not get stored in his cortex; unless you were his only customer or if you ordered something unusual, the waiter will not remember your order the next day. This is called short-term memory.

Another example of short-term memory is momentarily committing to memory a telephone number provided by directory assistance. You keep this information in your hippocampus for only a few minutes, perhaps until after you dial the number. You quickly forget this phone number since your hippocampus does not consider it worthy of long-term memory. Still another short-term example occurs when you listen to the morning news on radio or TV. Within minutes of hearing it, you can list most of what you learned. Once you leave the house, however, you probably forget most of the news and remember only the stories that you consider relevant. You subconsciously erase all the information that is not meaningful to you.

Hippocampus: Gateway for New Memories

You might be wondering how scientists discovered that learning new names and phone numbers happens in the hippocampus, and not some other corner of the brain. The important discoveries in this field have come from studies of patients who had surgery in the memory portions of their brain as well as studies with animals.1

In the 1940s, Wilder Penfield, M.D., a neurosurgeon at the Montreal Neurological Institute in Canada, placed a small electrode on the surface of the brain during brain tumor surgeries. In this way, he could record the electrical activity of those brain cells so he wouldn't remove any of the normal cells along with the tumor. Since the brain itself cannot feel pain, he could perform this type of surgery under local anesthesia.

Dr. Penfield was able to also deliver small electrical shocks and see if the patient's arm twitched. After recording and stimulating the surface of the brain-the cortex-in more than one thousand patients, he was able to map where different functions for control of arm movements, vision, and sensation in the hands were located on the cortex. In some patients, the stimulation of areas around the hippocampus led to a coherent recollection and description of an earlier experience. These memorylike responses could not be elicited elsewhere in the brain. Thus, it appeared that the hippocampus and its neighboring structures were important for memory.

In some rare patients, the hippocampus on both sides had to be removed to relieve severe seizures that could not be treated with medications. Brenda Milner, Ph.D., professor of psychology at McGill University in Montreal, worked with Dr. Penfield and studied the memory of these patients before and after surgery. She discovered that though they had completely lost their ability to make new memories, they could still recall old memories. One of her patients was Mr. H. M. She would talk to him for ten minutes, leave the room, and when she returned half an hour later, he would greet her as if he had never seen her before. If she left the room and returned a third time, he was just as surprised when she told him her name. These patients would listen to the same joke three or four times and laugh each time as if they'd never heard the joke before. Without a functioning hippocampus, they were unable to "acquire" and learn new information. And yet, they could tell stories from childhood, high school, or any time period before the surgery, which meant that even without their hippocampus they could still recall old memories.

Carol Barnes, Ph.D., professor of psychology at the University of Arizona, has recently performed studies in rats that show how cells in the hippocampus are important for remembering the location of food in their environment.2 She placed small recording electrodes in the brains of the rats to track the activity of cells in the hippocampus as the rats looked for food pellets in a maze. When the rat was not searching, the cells showed no activity. When the rat approached the location where it thought the food should be, based on previous experience, the neurons would start responding. This study showed that certain cells in the hippocampus had learned the location of the food in the maze and would show increased activity when the rat went to that location.

Other researchers have performed similar experiments with monkeys. They found cells in parts of the cortex that show increased activity if the animal saw a familiar face, but not other faces. These cells are parts of a network devoted to remembering faces.3

The hippocampus is the gateway for the formation of new memories. In a simplified computer analogy, it works as RAM (Random Access Memory), where information is kept for a brief period of time. In this analogy, the cortex serves as the hard disk where permanent memories are kept.4

PROCEDURAL MEMORY

You learn how to ride a bicycle by trial and error. You fall a few times and then you gradually discover how to keep your balance without falling. When you first learn how to play tennis, you hit the ball all over the court (and get frustrated) until you figure out the best way to hold the racket and hit the ball so it will go over the net and land inside the other person's court. You "get a feel" for the racket, the ball, and the court. Similarly, when you first learn how to peel a cucumber, tie your shoelaces, or learn to dance, you acquire new skills by physically performing the same movement over and over again. Procedural memory is operating whenever you have to repeat certain hand or leg movements to learn something new. You could never perform these movements well just by reading about them or watching them on television; you must physically do them.

Dr. Brenda Milner discovered that procedural memory does not depend on the hippocampus. She saw that patients who had selective damage to their hippocampi could still perform and learn new skilled hand movements, even though they could not learn any new names, phone numbers, or dates. For example, you could teach them how to trace the edges of a star by having them look at their hand indirectly in a mirror. They initially found it difficult and spent a great deal of time on the task, but they improved with practice. However, when told that they were getting better with daily exercise, they might say, "What are you talking about? I've never seen this task before."5

If not in the hippocampus, then where does the procedural memory take place in the brain? Learning new dance steps or learning how to use chopsticks to eat Chinese food takes place, at least in part, in the cerebellum and the basal ganglia. The cerebellum is an apple-sized structure sitting at the back of the brain, near the neck. Basal ganglia are a constellation of brain areas located at the base of the brain. As you'll see in the later chapters, these areas are less prone to damage with aging or in Alzheimer's disease.

The fact that a different part of the brain is involved for learning new movements than the part used for learning new names and facts is good news for patients with Alzheimer's disease. It means we can enhance the quality of their lives by teaching them exercises that involve the arms and legs-at a time when their ability to learn and understand written and spoken language is limited. Learning a new fun game brings smiles not only to the faces of these patients, but also to the faces of their families and caregivers.

Perfect but Slower Memory Skills

As you grow older, some degree of wear and tear in your body is inevitable. You may walk slower, find that your bowel and bladder don't work as regularly as they used to, and need glasses or hearing aids. It would be reasonable to expect that your memory would show some mild slowing too. However, while most people don't mind walking slower, having a weaker grip, or seeing things less clearly, they very much mind having difficulty with their memory. People attach more meaning to their mental slowing than they do to their physical slowing.

Several research studies have indicated that it is only the speed of the learning process that slows down with aging and that the elderly maintain their baseline ability to learn and remember. In Denver, Colorado, at the April 2002 meeting of the directors of the Alzheimer's Disease Research Centers in the United States, Tim Salthouse, Ph.D., drew on his research in discussing memory in people from age eighteen to eighty. Part of his data was collected from vocational companies that test employees who ask for promotions. The subjects were of course motivated to do well since their managers could use their test results in deciding if they deserved to be promoted.

Examining the memory performance of this research group through advancing decades of life, Dr. Salthouse found, perhaps not surprisingly, that the older a person was, the slower his performance was.6 Thus, the thirty-year-olds were slower than the twenty-year-olds but faster than the forty-year-olds. A similar decline across ages was noted with respect to their visual acuity and grip strength. However, the subjects maintained their ability to learn new things-though at a slower pace-way into their eighties.

Though it would be great to be able to learn new things as quickly as when you were a child, it is not essential for success. In today's society, people over age sixty-five rule the country. The most outstanding senators, judges, doctors, lawyers, economists, and CEOs are not the men and women in their thirties, but are the individuals who carry with them several decades of experience and know-how. Their brains and memories work quite well. Such individuals have the advantage of having both knowledge and wisdom. The main disadvantage for them lies in their speed of processing information: They are indeed slower than they once were. Contrary to the proverb that says "You can't teach an old dog new tricks," you can. It just takes longer.

Mr. and Mrs. Gonzales attend tango lessons in a dance studio in Texas almost three nights a week. They are in their seventies. They find it difficult to perform many of the complicated steps and need more time to master them. They keep practicing-and are having fun doing it. They dance much better than some of the younger couples in the class.

The good news is that as you can improve your physical health and minimize age-associated decline with respect to strength and stamina, you can also strengthen your memory muscles and become better at learning and remembering-regardless of your age. Researchers at the University of Texas at Austin have developed an eight-session cognitive enhancement program entitled, "Memories, Memories, Can We Improve Ours?" Before and after presenting this program, they tested 19 older adults whose average age was eighty-three. The subjects showed a significant improvement in prospective memory items, such as asking for an appointment, asking for a belonging, and delivering a message.7

This illustrates an important point: It is never too late to start improving your memory. You can get better at remembering things even if you are in your eighties. Most people stop trying to challenge their memory as they grow older because they assume they've lost their mental strength. They are often surprised with their own performance after making an effort. To be successful in shaping up your memory muscles, you need to concentrate, be motivated, and be determined. There's no reason why you cannot maximize your mental fitness-just as you can maximize your physical fitness-at any age. In future chapters, you'll discover the specific steps you can take to achieve this goal.

Sight, Sounds, and Memory

At the beginning of the chapter we discussed the three stages of memory: acquisition, storage, and retrieval. The acquisition step involves the entry of information from the world around you-through mostly your eyes and ears-to your brain. If you only can absorb half the material you're exposed to, you cannot expect yourself to remember all of it. If you have poor vision or hearing, which is common among the elderly, your ability to remember it all will be limited.

As an older person, you may need glasses and/or hearing aids, or you may need to adjust the glasses or hearing aids you already have. Unfortunately, most older individuals do not adjust these important sensory devices on a regular basis. In a study of people of advanced years with hearing aids, scientists found that a quarter of the group had hearing aids that were not functioning properly. When they tuned the hearing aids, patients appreciated how much better they could hear. This may sound trivial, but it's very important because the acquisition of information relies on the sensory stimulation by sight, sound, taste, touch, and smell. If your brain cannot fully hear the name of a person you are meeting for the first time, you can hardly expect yourself to remember that person's name when you see them at a later time. Sometimes people confuse difficulty with hearing and communication with early Alzheimer's disease.

Mr. White, a delightful eighty-six-year-old retired schoolteacher, came to my office accompanied by his wife. She was concerned that he was exhibiting early signs of Alzheimer's disease. He did not like answering the phone or listening to the news on the radio, and he would forget the names of acquaintances. After talking with him, I learned that he had not checked his hearing aids in a long time and could barely hear me. He explained that he continued to handle their household finances, did crossword puzzles daily, and kept up with current affairs through reading the newspaper. He did not like answering the phone because he felt that "people speak too fast these days." His formal tests showed some mild memory problems and an outstanding score for his math and language skills. I felt that given his level of functioning at the age of eighty-six, he did not have Alzheimer's disease. He had some mild forgetfulness that was acceptable and would most likely show improvement with better sensory input (hearing). Prescription: He needed a good pair of hearing aids.

Mr. White's case contains an important point regarding memory and old age in our society. Life moves faster today than it did forty years ago. Newscasters and reporters on the evening news speak rapidly and often in truncated sentences. Even animated TV shows like The Simpsons and cartoons roll in a much quicker pace than did the Flintstones or Bugs Bunny. People swamped by deadlines and appointments sometimes speak at the speed of light. Elderly people find it difficult to keep up with the fast tempo of information presented to them. Once they have the opportunity to register the information at their own pace, they can remember it just as well as a younger person, if not better. In the example above, Mr. White had read most of the news in the newspapers at his own pace, rather than getting news from TV programs, and was up-to-date on events around the world.

One of the most memorable classes I attended at Harvard Medical School was a small group session about evaluating the elderly. To appreciate what they might experience on a daily basis, we were given goggles, earplugs, and gloves and were asked to thread a needle. We realized how frustrating it was not to see, hear, and feel our hands well. We learned how difficult it must be to keep up with the fast pace of modern life as we age. This exercise helped us realize that we need to slow down when we interact with our elderly patients.

Teenagers versus Retirees

Memory problems are not limited to older adults. Even teenagers and people in their twenties forget things. The difference is in how younger and older adults view lapses in their memory. When a teenager forgets the name of a classmate or where he left his books, he'll probably ignore it or think it's funny. He most likely moves on to other things and does not dwell on his memory failure. Later, while eating dinner or talking on the phone, he may remember the information.

Older people may have the same frequency of memory lapses, and they too will remember what they had momentarily forgotten. However, when these "senior moments" happen, they become alarmed. They lack confidence in their memory and fear that they may be starting to show the first signs of aging or Alzheimer's disease. The best approach for everyone is not to dwell on these moments, to realize that they are normal throughout everyone's life, regardless of your age.

Memory Lapses and Laughter

In his book Memory, Barry Gordon, M.D., Ph.D., professor of neurology at Johns Hopkins Hospital, suggests that if you can laugh about your memory lapses, other people will laugh with you and tell you about their own experiences. Dr. Gordon describes a story that illustrates this point:

A hostess was introducing her old and dear friend at a party and suddenly forgot her name. She looked at her friend and laughed. Her friend noticed that she had blocked on her name and went on to introduce herself. She could relate to similar experiences in her own life. At the end, everyone laughed and no one was embarrassed.8

Variation in Memory Performance

According to Marilyn Albert, Ph.D., professor of psychiatry and neurology at Harvard Medical School, there is a great deal of individual variability in learning and memory among the elderly, much more so than among a group of young adults.9 People have different color eyes, height, level of intelligence, and not surprisingly, different capability for learning and memory.

Starting from high school, some individuals have inherently better memories and seem to know everyone's name at a party and do well in memory puzzles. This variability among people increases throughout the advancing decades of life, in part because of each person's educational experience, physical health, and occupational achievements. You could either have a photographic memory or struggle to remember a grocery list, and yet in either case be considered "normal" as long as it's how you've been all along. In other words, each person is different, and "normal" for that person is based on what he or she was able to do a few years earlier, not necessarily on what other people his or her age can do.

Mr. Lewis, a handsome ninety-one-year-old gentleman, was a retired engineer. He had a very active lifestyle, and he showed me a list of 20 things he had to do the day he came to my clinic. During the week, he was busy taking care of his stocks, attending to his family, and reading technical journals. Recently, he was concerned by the fluctuations in the stock market, and he decided to sell some of his shares and invest in mutual funds. On weekends, he worked on repairing the wings of his airplane. He loved to fly by himself. His physical and mental health were comparable to most sixty-year-olds. He had a propensity to forgetfulness, so he made a habit of using "to do" lists. Despite his old age, Mr. Lewis showed no signs of slowing down. When I asked about the secret for his longevity, he laughed and said, "A positive attitude and a smile."

A great deal of the differences among people with regard to their mental faculties is a reflection of their early childhood education and their habit of learning new things throughout life. Concerning physical fitness, there are similar variations among people. Some of the elderly participate in triathlons, while others take long walks. Here, too, past experiences contribute to variability among the elderly; those who exercise regularly are less likely to develop physical disabilities.

There's Hope

The fact that you have vivid memories of Neil Armstrong's landing on the moon or the events of September 11 shows that you can have perfect memory for life. As you grow older, you do experience some slowing in the process of making new memories and remembering old ones. However, according to Dr. Marilyn Albert of the Harvard Medical School, once you give yourself enough time to learn the material well, you do not forget what you've learned any more rapidly than younger people.10 You need to be realistic with your expectations and realize that your brain memory system is designed for you to remember things that are relevant and important-not all the details of everyday life. As you will see in future chapters, you can maximize your learning ability by improving your brain function-through reducing the risk factors that slow down your brain and increasing those factors that enhance your brain.