Remember when . . . remembering was easy. Actually, everyone forgets things from time to time; memory "glitches" are common for people at any age. And as we get older, some mild memory loss is absolutely normal.
There is still much we don't know about how the human memory works, and various theories abound. However, scientists agree that "memory" is a generic term that really refers to several different types of memory, stored by distinct mental processes into different parts of the brain. Most scientists discuss two types of memory: short-term and long-term. Some add a third: sensory memory.
Sensory memory consists of the instant information given us by our five senses. This information lasts in memory for a very brief time (from a few hundred milliseconds to one or two seconds), so briefly that some scientists don't think of it as memory at all, but part of the process of perception. Others, though, say it's the first step in the making of short-term memory.
Short-term memory is essentially a small amount of information that is retained for a brief period of time (from a few seconds to about thirty to forty-five seconds or so) and for a specific purpose. For example, a telephone number you look up and soon call (without writing it down) is a piece of information stored in short-term memory. Experiments show that most people can hold about seven items in short-term memory. The most familiar experiment is to have the subjects look at a list of words or numbers, then close their eyes and try to repeat them in order. Most people can repeat about seven.
Some scientists also speak of working memory, information that is stored in short-term memory, then quickly put to use, such as that phone number you look up and call. If the information isn't used quickly, or seems no longer useful, it fades from the memory. A few minutes after making the phone call, you may not remember the number. But if the information is used and reused, it may begin moving into long-term memory.
Long-term memory is a perhaps unlimited amount of information that is retained indefinitely. Indefinitely means any time longer than short-term: from minutes to hours to decades and more.
Long-term memory is further sub-divided into recent and remote.
- Recent long-term memory includes information stored for hours or weeks, such as what you ate for breakfast, or who you visited two weeks ago.
- Remote long-term memory includes information stored for months and years and more, such as the names of your elementary school teachers.
Recent and remote obviously refer to how long the long-term memory is. But there are other ways to sub-divide long-term memory. For example, scientists also speak of:
- Declarative or explicit memory: information that you deliberately work at remembering (or memorize), and that you can describe in words, such as the names of the presidents or the meanings of words.
- Non-declarative or implicit memory: information you use to do something, such as drive a car or tie a tie. This "procedural" information is generally remembered automatically (when you drive, you don't have to work at remembering how) and is not described in words.
- Semantic memory: information so deeply ingrained and used so often that virtually no effort is needed to remember it, such as the name of the current month.
The process of making memories has several steps:
- Acquisition: gaining a new piece of information, which is first put into short-term memory.
- Consolidation: moving the information from short-term to long-term memory, a process that can take several weeks or even months.
- Retrieval: recalling or remembering the stored information so it can be used in some way.
Short and long-term memories are stored in different parts of the brain. Scientists are still exploring the "anatomy of memory" and the consolidation process. However, there's general agreement that the brain's frontal lobe houses the short-term memory, and consolidation involves moving information from the frontal lobe through the hippocampus to other areas.
- Scientists generally divide memory into short-term memory, often called "working memory," and long-term memory. Long-term memory is further divided into recent and remote.
- Short and long-term memories are stored in different parts of the brain. Although the "anatomy of memory" is not completely understood, it's generally agreed that the brain's frontal lobe houses the short-term memory, and that information moves from the frontal lobe through the hippocampus to other areas for long-term memory storage.
- Experiments show that most people can hold about seven items in short-term memory. Try this. Read these numbers aloud at a rate of about one per second:
3, 9, 4. 6, 7, 9, 2, 4, 3, 8 - Now, close your eyes and try to recite them back, in order. How many did you get?
- Though memory and learning are connected, scientists distinguish between them.
- Memory is the ability to remember stored information and experiences.
- Learning is a process that in some way affects or changes the actions that follow it. For example, learning to read changes the way you look at a book.
- Obviously, learning depends on memory; to speak a language you've learned, you must remember its words. But memory also depends on learning; memory can be called the record of what you've learned.
- A certain amount of memory loss is common as we get older. It is not necessarily a sign of dementia. But memory loss that interferes with daily living should be discussed with a doctor. For example:
- Occasionally forgetting where you put the keys is not a sign of dementia; putting the keys in the refrigerator may be.
- Occasionally forgetting where you put your eyeglasses is not a sign of dementia; forgetting that you have eyeglasses may be.
- Many things other than aging and dementia can cause memory loss, including reactions to drugs, head injuries, poor nutrition, some diseases, and emotional problems such as stress and depression.
- Just as physical exercise keeps your body in shape, mental exercise (reading, writing, social interaction, mentally challenging games, etc.) can keep build up your mental abilities and offset the mental effects of aging.
- What's good for the body is also good for the mind. A healthy lifestyle, including physical exercise, a healthy diet, and no-smoking, is brain healthy.
Ask Your Doctor
This list of questions is a good starting point for discussion with your doctor. However, it is not a comprehensive list.
- Do I have normal, age-related memory loss or something else?
- What tests can I take to determine this?
- How severe or dangerous is my memory loss?
- Could my memory loss be a reaction to a drug I'm taking?
- Could my memory loss be caused by poor nutrition, dehydration, or my emotional state?
- Could my memory loss be caused by other medical problems?
- Is there anything I can do, or any medicines I can take, to treat this condition?
- Are there any lifestyle changes (including diet and exercise) that may help prevent further memory loss?
- How can I learn to cope with the loss? What changes should I make in my daily routine?
- What signs or symptoms should I look for to see if the loss is getting worse?
Key Point 1
As we grow older, forgetfulness can be part of the normal process of aging. While normal aging may entail some neurological changes, not every memory problem is a symptom of dementia.
There are several different types of memory, stored by distinct mental processes into different parts of the brain. The normal memory loss that accompanies aging usually affects recent long-term memory, but not short-term or remote long-term memory. For example, you're introduced to a couple at a party. As you chat with them, their names and faces enter your recent memory. But an hour or so later, you find you don't remember their names.
Aging can also affect explicit memory, but has less or no effect on implicit and semantic memory. For example, you may have some difficulty remembering something you used to know so well, such as the order of the presidents, or you may find yourself searching for that word that's on the tip of your tongue.
The reason for all this is that retrieving information from the memory involves a complex series of chemical and electrical activities in the brain and nerve cells. As we age, we produce less of the needed chemicals, and the cells may decay or work less efficiently.
If these problems are common with aging, then what isn't normal? That is, what may be symptomatic of something more serious, such as dementia or even Alzheimer's disease?
The quick answer is that serious memory loss is severe and affects your everyday life. For example, occasionally forgetting where you put the keys is not a sign of dementia; putting the keys in the refrigerator may be. Forgetting where you put your eyeglasses is not a sign of dementia; forgetting that you have eyeglasses may be.
The more detailed answer notes that dementia has many symptoms other than simple memory loss, such as:
- Forgetfulness that affects work: while nearly everyone occasionally forgets names or appointments, if this happens frequently and is accompanied by confusion, it might signal a weakening of the memory.
- Problems with normal tasks, such as cooking, cleaning, dressing, getting to a place you've been to often, following directions for any activity that requires several steps: it is common to forget the pot on the stove; it is less common to forget that you've cooked at all.
- Memory loss that seems to be worsening as time goes on.
- Problems with words: again, it is common to have trouble finding the "right word;" it is less common to forget simple words and use inappropriate fillers that make a sentence sound garbled.
- Problems with space and time, that is, knowing where you are and what time it is, or being unable to keep track of what happens each day: we all get disoriented occasionally, but consistently getting lost in your own house is a good reason to seek medical help.
- Problems with judgment: you may normally disagree with your loved ones about what is "appropriate dress" for a specific event, but wearing a bathrobe to go shopping or three sweaters on a hot summer day is another warning sign of dementia.
- Problems with abstract thinking: many of us have trouble balancing our checkbooks, but people with dementia often can't recognize numbers or do simple arithmetic.
- Mood swings and changes in behavior: we all get mood swings, but for people with dementia they can be very sudden and seemingly inexplicable.
- Personality changes: personalities do change with advancing age, but for people with dementia these changes may be more sudden and much stronger; for example, a generally friendly, outgoing person may become cold, angry, jealous or quiet.
- Loss of initiative: while no one stays motivated constantly, people with dementia may lose all interest in their work, hobbies, friends, etc. without developing any new interests.
For more information about dementia, see Second Opinion, Dementia (Episode 101).
Distinguishing normal, mild memory loss from more serious forms requires some diagnostic testing. For information on this, see Key Point 2.
On the other hand, memory loss can have many causes other than dementia, such as:
- Reaction to drugs: among the medicines that can interfere with memory are:
- Sleeping pills (both over-the-counter and prescription)
- Anti-anxiety drugs
- Some anti-schizophrenia drugs
- Drugs for post-surgery pain
- Drug interactions: the result of taking multiple drugs at the same time
- Abusing alcohol and illicit drugs
- Concussion or head injury: even minor head injuries can sometimes cause memory loss
- Thyroid problems
- Lack of sleep
- Poor nutrition, especially a lack of vitamins B1 and B12
- Dehydration (not having enough fluids)
- Emotional issues: older people facing major life changes such as retirement, moving, loss of friends and loved ones, are especially prone to:
Memory loss produced by most of these causes is usually reversible. That's why, if you speak to a doctor about memory loss problems, it's important to be open, honest, and – most of all – complete. When the doctor has the total picture of your current situation, she or he is better able to give an accurate diagnosis and suggest ways to treat your condition.
Key Point 2
In the future there may be more medical options for age-related memory loss and even dementia. In the meantime, the same life habits that result in a healthy heart-a good diet and regular exercise-also promote a healthy brain.
To distinguish the normal memory loss that often accompanies aging from more serious forms, doctors use a number of diagnostic tools. One is to get a detailed medical history. This is a series of questions asked by the doctor to get as complete a picture as possible about the incidents of memory loss. Questions might cover:
- What type of memory is affected: short-term; long-term; both?
- Is the memory loss affecting your daily activities at work or at home? Can you still function independently (getting dressed, eating, etc.)?
- Is your memory loss connected to a specific event: have you forgotten what happened soon after or before some major event?
- Are you making up stories to cover memory loss?
- How long has the memory loss been happening: weeks; months; years? Is it getting worse or staying the same?
- Is the memory loss constant or are there distinct episodes of forgetfulness or "amnesia?"
- Have you had any
- head injuries
- emotionally traumatic events
- recent general anesthesia
- episodes of abusing drugs or alcohol?
- Do you have other symptoms, such as
Another diagnostic tool is a set of psychometric tests, questions that explore your mental status and measure your ability to think (cognitive skills). Questions might cover areas such as:
- Orientation: do you know
- the time, date, and season
- where you live
- your name, age, occupation?
- Attention span: can you
- complete a thought
- follow a conversation
- follow directions
- Recent memory: can you answer questions about recent events, places, and people in your life
- Remote memory: can you answer questions about events, places, and people from your distant past
- do you know the words for familiar objects
- is your ability to read, write, and speak intact
- Judgment: can you explain what you would do in various situations
Along with these mental tests, doctors can also use a number of physical examination tools, including:
- Neurological exam
- CT scan or MRI of the head
- EEG (electroencephalogram, a test that looks for problems in the brain's electrical activity)
- Blood tests (to look for specific diseases)
- Lumbar puncture (also known as a spinal tap, to examine the fluid that surrounds the brain and spinal cord)
Today, there are no "miracle cures" for the affects of normal aging on memory, nor any pills to prevent it. For example, there has been a lot of discussion about the memory improving effects of the herb, Ginkgo biloba. But the research evidence is still very uncertain. Research also continues on other drugs that someday may help improve various mental functions, including memory. For more information about this, go to Key Point 3.
However, there are effective ways to delay the onset of normal memory loss and to cope with it as it happens. The most effective preventive technique is simply to live in a way that promotes general health. What's good for your body is also good for your brain. That means:
- Start and maintain a program of regular physical exercise
- Stop smoking
- Stop drinking alcohol heavily
- Keep your blood pressure under control. If you need blood pressure lowering medicine, get it and use it.
- Keep your cholesterol under control. If you need cholesterol lowering medicine, get it and use it. Eat a healthy diet.
There are also techniques that can help you cope with memory problems. In general, following a routine, keeping things in the same place, and writing down appointments will help you keep your life organized and on track. More specifically, try these techniques:
- Keep keys, glasses, wallet or handbag, and other important, frequently used items in the same place.
- Use a calendar, electronic organizer, daily planner book, or a simple sheet of paper to list one-time appointments as well as things you do frequently; also list bills to pay, errands, etc. as well as important dates (birthdays, anniversaries, etc.); keep this information with you.
- Keep your address book updated and in the same place.
- Follow a daily routine as much as possible.
- Make associations (connect things in your mind), such as using landmarks to help you find places.
- Repeat names when you meet new people.
Key Point 3
We live in a culture where multi-tasking and quick response is the norm. While these skills may diminish as we grow older, there are functions that remain untouched and may even improve with aging - reasoning, wisdom, creativity. Staying active and socially engaged helps keep these functions intact.
No drugs are currently available that can prevent or cure the effects of normal memory loss caused by aging, but some drugs developed to treat other conditions have been used "off-label" (not for their original intent) by people with the condition. One example is modafinil (the generic name for Provigil), a prescription-only drug approved to help people with excessive daytime sleepiness).
Further, a lot of research is being done about dementia and memory loss. One small study found that donepezil (the generic name for Aricept), a drug used to treat Alzheimer's patients, helped the mental performance of healthy people. Other research is concentrating on manipulating CREB, a protein that helps memories get stored in the brain.
All of this suggests that we may soon enter an era where drugs will be able to improve a variety of mental functions, including intelligence, reflexes, attention span, mood, and memory. This has led to the creation of the term cosmetic neurology. The term draws an analogy between plastic surgery done on physically healthy people who simply want to "look better" and drugs given to mentally healthy people who want to "think better."
Plastic surgeons originally practiced their art on the mangled bodies and faces of people ravaged by war, accident, and disease. Now, many devote themselves to elective cosmetic surgery, improving the appearance of perfectly healthy people. This gives rise to a host of complex ethical and moral questions. The most general is: what is the purpose of the medical profession - to help those who are sick or to improve the quality of life of those who are already healthy? Moreover, there is the additional and quite complicated comparison between athletes who take drugs to enhance their physical performance, and ordinary people who take drugs to enhance their mental performance. While athletes have been mostly criticized for this, will attempting to "boost your brain" be seen as a positive? For example, would air passengers feel safer with a pilot who has taken such a drug before a major flight? It will take time for these issues to be resolved – if they ever are. Meanwhile, the research will continue.
An important area of research concerns the theory of cognitive reserve. It was first proposed in the late 1980s, when it was found that some people whose brains had had all the physical symptoms of Alzheimer's (including "plaque" or clogged blood vessels) managed to avoid developing any of the mental symptoms. To explain this, scientists theorized that these people had a larger "stockpile" of mental abilities that helped them fight the effects of Alzheimer's.
This could be thought of as comparable to athletes whose stronger, more developed muscles are better able to fight physical ailments. And just as muscles can be developed with exercise, so a lifetime of mental stimulation (such as continuing education, a job that engages the mind, mentally challenging leisure activities, etc.) may help you develop a cognitive reserve to fight the mental ailments that aging may bring.
That's why staying mentally active and socially engaged are so important. Some scientists say that reading, writing, learning new skills, doing puzzles, playing games, and even activities like gardening stimulate brain cells and the connections between the cells, and may help lower the risk of dementia. You certainly don't need to believe any hype promoting crosswords, Sudoku, and other puzzles and games as a magic mental cure-all, to accept the simple fact that the mental exercise they offer is healthy and helpful.
Similarly, it should be obvious that staying in touch with friends and loved ones, remaining socially active and involved with community organizations (charitable, political, social, and other groups) is an effective way to ward off boredom and loneliness. Both boredom and loneliness can increase stress and, as mentioned earlier, emotional issues including stress have been associated with an increased risk of memory loss and dementia.
Ultimately, the ancient ideal of a "sound mind in a sound body," developed through physical and mental exercise, remains the best prescription for a long, healthy life.
Conduct an off-site search for Memory Enhancement information from MedlinePlus. These up-to-date search results are based on search terms specific to Second Opinion Key Points.
Memory- main page
Dementia- main page
This episode of Second Opinion explores the different forms and causes of dementia, the difference between dementia and Alzheimer's disease, and how the effects of dementia may be slowed down by medical intervention.
The Food and Drug Administration (FDA) is the Federal government agency that monitors the quality of food and medicine. This is a link to their fact sheet about memory and memory loss that summarizes a great deal of useful information.
The National Center Complementary & Alternative Medicine is one of the National Institutes of Health. This link takes you to their discussion of Ginko bilboa, an herb that has been promoted as a memory aid.
The National Institute on Aging is another of the National Institutes of Health and has a great deal of information about aging and about resources available for dealing with age related health problems.
This is a concise, complete, fascinating, and fun to read introduction to the human brain in general and human memory in particular. Among its other useful features, the site offers three levels of explanation to choose from.
Family Doctor is an on-line medical information site for the general reader. This link takes you to their very helpful article on age related memory loss.