Most people get a little forgetful as they age. More often than perhaps you would care to admit, you find yourself marching around the house in a huff, searching for misplaced car keys, eyeglasses, or a purse. Or perhaps somebody you met the previous week waves to you on the street, and the person’s name dances teasingly at the tip of your tongue for a second or two before you finally remember. At these times, you might find yourself muttering under your breath: "I must be getting Alzheimer’s or something."
In fact, you are probably not. Minor memory lapses, though perhaps annoying, do not necessarily herald the beginning of Alzheimer’s disease. As long as memory slips don’t start to interfere with your ability to work, run a household, or function in a marriage or other type of personal relationship, you probably have little to be concerned about.
Aging and Forgetfulness
Scientists and physicians have come up with various ways to describe memory loss due to normal aging. The most basic definition is simply that, as we grow older, the ability to learn new information and recall it at will declines somewhat; for most of us, this decline falls within the average (i.e. normal) range expected for people our age. Forgetfulness is only a cause for concern when the severity of it falls below that normal range.
Forgetfulness due to aging goes by different names. One name in wide use is age-associated memory impairment, or AAMI. This diagnostic category is used to identify people who show a minor-to-moderate decline in memory, but who remain essentially healthy. To be diagnosed with AAMI, you must meet all of the following criteria:
- You are at least 50 years old;
- You have noticed that your memory is not as sharp as it used to be;
- Other possible causes for your memory slips besides the effects of aging have been ruled out. These other factors include a recent heart attack, chronic insomnia, reactions to medications, and Alzheimer's disease;
- Your score on a standardized memory test is lower than that of an average 25-year-old. This is a way of confirming that your memory is likely to have declined since you were younger.
According to psychologist Steven Ferris, Ph.D., director of the Silberstein Aging and Dementia Research Center at New York University School of Medicine, research conducted to date suggests that up to half of all people 50 or older would meet the criteria for AAMI. Clearly, age-related forgetfulness is widespread. Not everybody over age 50 becomes noticeably forgetful; but many of us will show some degree of AAMI at some point in our lives.
What is Forgotten
Thanks to a lot of research on healthy aging people, the effects of ordinary forgetfulness are well understood. Clearly, AAMI doesn’t affect the recall of established memories, such as where you grew up, or the songs you learned how to play on the piano. What AAMI does affect is the ability to learn and recall new information, as in: "Where did I leave those darn scissors? I just put them down!" As such, what we think of as Age-associated memory loss is really more like age-associated learning loss.
Many studies on healthy volunteers back this up.
For example: research by Marilyn Albert, Ph.D., a professor of psychiatry and neurology at the Harvard Medical School, suggests that the rate at which people acquire new information slows down as they age. Unfortunately, the rest of the world doesn’t always slow down along with our aging brains. Information floods into our lives–new names, new faces, new skills to master–but not all of it gets stored as enduring memories. As a result, we may think we’ve forgotten things that were never really stored in memory in the first place.
On the plus side, although it takes older people longer to learn new information, once they do so they can usually recall it just as well as a younger person. For most of us, mild forgetfulness can be overcome with a little extra effort: by paying closer attention when meeting new people, or by taking things a little more slowly. AAMI "shouldn’t even impair fairly complex activities of daily living, such as filling out a tax return," Ferris emphasizes. "It may take you a while longer to do your tax return, but you’re still going to get it done, and it’s going to be accurate."
Sometimes memory problems do surpass ordinary age-associated forgetfulness. When do you know you’ve crossed the line? From a medical point of view, memory loss is considered a problem when it falls below what is normal for a given age group. Memory researchers have introduced a new term for the first step into abnormal forgetfulness: mild cognitive impairment, or MCI.
The memory lapses of MCI are more severe than age-related forgetfulness. In memory tests, people with MCI retain less information than most people of their age. And this memory impairment is also persistent, interfering with normal daily routines.
For example: a person with AAMI might occasionally forget the name of a casual acquaintance for a few seconds. In contrast, a person with MCI would repeatedly struggle to remember the names of close colleagues during meetings–the sort of episodes that can cause real problems in a person’s professional life.
Crossing the line from MCI to Alzheimer’s disease involves a much bigger jump, both in the kinds of problems encountered and their severity. The person must show not only abnormal memory impairment for his or her age group, but also additional impairments in other mental skills. For instance, becoming disoriented or confused while shopping for groceries at a neighborhood store, or while calculating the household finances, could be a sign of Alzheimer’s disease. According to the studies to date, about 12 percent of people 65 or older previously diagnosed with MCI cross over to Alzheimer’s disease every year.
Research on healthy aging people has greatly improved our understanding of both normal and abnormal forgetfulness. But ultimately you are perhaps the most qualified judge of whether memory impairment has crossed the line from an occasional lapse to a persistent and disruptive problem. If your forgetfulness has begun to interfere with day-to-day living, talk to your doctor and get an evaluation. Since anxiety and fearfulness are themselves causes of memory loss, that evaluation could lead to peace of mind–and maybe even get you started on the road to remembering where you left those eyeglasses.