It’s normal to forget some things, and to become a bit more forgetful as you age. It’s also normal to worry about forgetting. What isn’t normal is forgetting too much. But how much is too much? And how can you tell whether your memory lapses are part of normal aging or a symptom of something more serious?
Neuroscientists and physicians haven’t fully answered that question. But they have identified some key differences between normal lapses and those that occur with serious memory problems, like dementia, which is the progressive loss of memory and other mental abilities that interferes with a person’s daily activities.
The normal aging process leads to predictable changes in thinking and memory. These include “wear and tear” damage from oxidative stress — the reduced capacity to detoxify molecules or proteins that are harmful to brain cells — and declines in the energy-generating components of cells (mitochondria) that allow them to function optimally.
But such changes differ from pathological aging caused by conditions that damage the brain, like Alzheimer’s disease or cerebrovascular disease. Those conditions lead to a cascade of events that accelerates cellular dysfunction and death and are often associated with the accumulation of toxic proteins. When neurons are damaged or cannot function effectively, memory loss and a slowdown in information processing — known collectively as cognitive decline — can occur.
6 Types of Normal Memory Problems
Some people have the ability to remember things better than others, just as some people are better at math or athletics. Similarly, healthy people, regardless of age, can experience memory loss or memory distortion. Daniel Schacter, a psychology professor at Harvard University, describes what he calls six common “sins,” or flaws, of memory below. Some of these memory problems become more pronounced with age, but unless they are extreme and persistent, none are considered to be indicators of dementia.
- Transience. This is the tendency to forget facts or events over time. Although transience might seem like a sign of memory weakness, brain scientists regard it as beneficial because it clears the brain of unused memories, making way for newer, more useful ones.
- Absent-mindedness. This type of forgetting occurs when you don’t pay close enough attention to what you are doing or hearing; for example, misplacing your glasses or car keys. Because you were thinking of something else, your brain didn’t encode the information securely. Absent-mindedness also involves forgetting to do something at a prescribed time, like keeping an appointment.
- Blocking. This is the temporary inability to retrieve a memory — “It’s on the tip of my tongue.” Blocking occurs when a memory is properly stored in your brain but something keeps you from finding it. In many cases, the blocked memory is similar to another one, and you retrieve the wrong one. This competing memory, though, is so intrusive that you can’t think of the memory you want — like when you call your younger son by your older son’s name.
- Misattribution. This memory problem occurs when you recall something accurately in part, but incorrectly recall some detail, like the time, place or person involved. As with several other kinds of memory lapses, misattribution becomes more common with age, for two reasons. First, as you age, you absorb fewer details when acquiring information, because you have somewhat more trouble concentrating and processing information rapidly. Second, when you get older, your memories grow older as well — and old memories are especially prone to misattribution.
- Suggestibility. This is the vulnerability of memory to the power of suggestion — information that you learn about an occurrence after the fact. Suggestibility can be the culprit in recollections of incidents from your childhood that never really happened.
- Bias. One enduring myth about memory is that it records what you perceive and experience with complete, objective accuracy. In reality, your perceptions are filtered and influenced by personal biases — your experiences, beliefs, prior knowledge and even your mood at the moment — both when a memory is being encoded in the brain and when it is being retrieved. People prone to depression, for example, remember negative information better than positive information.
When to Worry
If you are worried about your memory (or that of a loved one), or if people close to you have noticed some troubling trends, see your primary care doctor for an exam. Because this doctor knows you and your medical history, he or she is in a good position to determine whether your memory symptoms are related to medications you are taking or medical conditions you have had.
Your doctor should not dismiss worries about your memory without even gathering additional information. You want to feel that your concerns are being taken seriously. But you can’t necessarily expect to walk out of your doctor’s office with a definitive diagnosis. No single test can pinpoint the cause of memory loss. The diagnostic process often requires a detailed history to understand the nature of the problem, as well as a physical exam, a variety of tests, and, depending on the results, monitoring over a period of months or even years. It may also be appropriate to be referred to a neuropsychologist, a doctor who specializes in the relationship between brain and behavior.
In some cases, addressing an underlying medical disorder or treating an emotional problem can lead to improvements in memory. For instance, people with depression or sleep disorders often find that treating those conditions improves their memory function, or at least prevents further decline. If an evaluation suggests that your memory problem does represent early dementia, starting treatment may help preserve memory and slow its loss.
If, on the other hand, an evaluation confirms that your problem is simply normal age-related memory loss, you can feel reassured, and begin to focus on strategies and lifestyle changes that can help strengthen your memory and promote brain health.
How Do Doctors Diagnose Dementia?
It may be helpful to consider some of the criteria physicians and experts in cognition use to determine if a patient is showing early signs of dementia. The following list is adapted from Diagnosis, Management and Treatment of Dementia: A Practical Guide for Primary Care Physicians, published by the American Medical Association.
- Normal Aging: The person complains of memory loss but can provide considerable detail regarding incidents of forgetfulness.
- Dementia: The person complains of memory problems only if specifically asked and cannot recall instances when memory loss was noticeable.
- Normal Aging: The individual is more concerned about perceived forgetfulness than close family members are.
- Dementia: Close family members are much more concerned than the individual is about incidents of memory loss
- Normal Aging: Recent memory for important events, affairs and conversations is not impaired.
- Dementia: Recent memory for events and ability to converse are both noticeably impaired.
- Normal Aging: The person has occasional difficulty finding words.
- Dementia: The person makes frequent word-finding pauses and substitutions.