How to distinguish memory problems due to normal aging versus Alzheimer’s.
Posted December 17, 2017
Coming home for the holidays, we are often with parents, grandparents, and other relatives not seen for some time. We may observe a slip of memory. Is it just because they are getting older, or is it a sign of Alzheimer’s (or another memory disorder)? Here’s how to distinguish what’s normal and what’s not.
Memory is like a filing system. The file clerk brings information in from the outside world, stores it in the file cabinet, and later pulls the information out when needed.
- Our frontal lobes are the file clerk.
- Our hippocampus is the file cabinet.
Older frontal lobes do not work as well as they did when they were younger. Although no one disputes this fact, there are different theories as to why. One is that it is due to the accumulation of tiny strokes in the brain’s white matter, the wiring that goes to and from the frontal lobes. Another theory is that there is deterioration of the neurons in the frontal cortex itself. Others argue that it is a normal, physiologic change.
Whatever the cause, when frontal lobes are older, the file clerk does not work as well as when she was younger. Thus, common changes in normal aging include:
- Information may need to be repeated in order to be learned.
- It may take more time for information to be retrieved.
- One may need a hint or a cue to retrieve information.
Importantly, in normal aging, if information was learned it should be able to be retrieved (perhaps with a bit of time and a hint).
In Alzheimer’s disease (and several other disorders), the hippocampus—the file cabinet—is damaged and ultimately destroyed. Think of pulling open a file drawer and finding a large hole in the bottom of it. You can imagine the best, most efficient frontal lobe file clerk bringing in information from the outside world and putting it into the file cabinet, only to have it disappear into the hole, lost forever. In this case, information cannot be retrieved even if it was repeated when learned, and time and hints were given. When this situation occurs, we call it rapid forgetting.
Rapid forgetting is always abnormal; a sign that something is wrong with the memory. Note that it doesn’t have to be Alzheimer’s—it could be something as simple as a medication side effect, vitamin deficiency, or thyroid disorder—but it should always be evaluated.
Common symptoms that occur because of rapid forgetting include:
- Repeating questions and stories
- Forgetting important appointments
- Leaving important things (such as the stove) unattended
- Losing things more often
Three other problems that may be noticed that can also indicate a problem and should be evaluated include:
- Difficulty with planning and organizing
- Difficulty finding ordinary words
- Getting lost (even on familiar routes)
Now let’s look at some examples:
- Your mother is leaving the mall and has to search for her car in the parking lot. This problem can occur as part of normal aging, particularly if she was distracted when she was parking. But it is not normal for her to search for over an hour, or to require assistance in finding her car.
- Your grandfather needs to repeat directions three times in order to remember them. Repeating information in order to learn it is helpful for anyone, particularly for older adults. Once the information is learned, however, it should not be quickly forgotten.
- Your uncle cannot recall the name of a restaurant until you remind him. Difficulty retrieving names of people and places can be perfectly normal and is more common as one gets older. He should recognize the name, however, when he hears it.
- You grandmother has asked the same question several times in one hour. Repeating questions may be due to rapid forgetting, which should always be evaluated.
- Your aunt used to be able to keep track of things, but now she’s hunting for twenty minutes each morning, and she’s had to replace some things that she cannot find. Losing things more than before can be a sign of rapid forgetting and should be evaluated.
- Your father can no longer do the simple household repairs that he used to. No longer being able to do common activities that he has done all his life because of problems with thinking and memory should be evaluated.
See Budson & O’Connor (2017) for more information.
© Andrew E. Budson, MD, 2017, all rights reserved.
Budson AE, O’Connor MK. Seven Steps to Managing Your Memory: What’s Normal, What’s Not, and What to Do About It, New York: Oxford University Press, 2017.