An excerpt from Why We Forget and How To Remember Better: The Science Behind Memory.
“I’m so worried about my memory,” says the 82-year-old accountant and mother of three. “All of my friends are having memory problems. Many of them have dementia, and some even have Alzheimer’s disease. I think I’m getting it too…I know I am. This morning I walked into my bedroom and could not remember what I was looking for—not until I walked back down to the chilly basement and remembered the sweater I had gone to get. And coming up with people’s names, forget it! If I don’t see someone regularly, I have a terrible time recalling their name. That’s not all. Last week, I was driving to the bank while my son was telling me about the grandchildren—they’re all doing so well—and the next thing I know I’m in the parking lot of the grocery store. I had no recollection of the driving for the last 10 minutes nor how I ended up at the grocery store instead of the bank.”
Is this 82-year-old accountant developing Alzheimer’s disease or aging normally? We will review the changes in memory that occur with normal aging as well as brain disorders of aging such as Alzheimer’s disease so that you will be able to tell them apart. We’ll also discuss how you can use the other memory systems that are relatively intact to compensate for some of the memory problems that occur in normal aging and various brain disorders.
Individuals who are aging normally in their 60s, 70s, and 80s experience some difficulty keeping information in mind in their working memory. They also need to use more effort to learn new information and to retrieve information when they need it from their episodic memory, and they have trouble recalling people’s names from their semantic memory. Experiencing these memory challenges with increased frequency as you age does not need to be cause for alarm. We’ll examine these difficulties, and then turn to procedural memory, which is relatively preserved in aging.
Older frontal lobes
Memory difficulties in normal aging often are related to changes that occur to the frontal lobes and their connections to the rest of the brain. Older frontal lobes just don’t function as well as they did when they were younger. Some researchers and clinicians believe this is due to a small amount of age-related damage to this part of the brain and its connections from tiny strokes or other pathology. Other researchers believe these changes to the frontal lobes are due to normal, physiologic changes not related to a disorder, such as an alteration in the prevalence of brain cell receptors that facilitates the stabilization of memories at the cost of diminishing the ability to form new memories.
Working memory in normal aging
Recall that the prefrontal cortex is the central executive of the working memory system. Since frontal lobe function decreases with aging, it should not surprise you that older adults show diminished working memory abilities relative to younger adults. Compared to those in their 20s and 30s, older adults generally cannot keep as much information in mind or manipulate it as easily. This means that, compared to when they were younger, older adults are usually slower to add up a column of numbers in their head and less able to keep in mind a map of a city they are visiting for the first time.
Episodic memory in normal aging
There are three major changes that occur in episodic memory as people age, all related to their diminished frontal lobe function. We’ll consider them each in turn, along with some simple measures you can take to compensate for these changes.
First, it takes more effort to pay attention and thus to get the desired information into episodic memory. Simply repeating information, however, can help you overcome this difficulty. So, try repeating your shopping list, an address you are driving to, or the day’s agenda a couple of times in order to remember them.
Second, it takes more time, effort—and often some strategies—to get the desired information out of episodic memory. With diminished frontal lobe function, your ability to search through your episodic memory to find and rebuild the memory you’re looking for is diminished. Sometimes just concentrating hard and giving yourself a bit of time is enough for the desired memory to come to mind. At other times you will need to use strategies to bring the desired memory to mind. Try to recall the location in which the memory was formed—that cue might trigger recall of the memory.
Third, older adults are more likely to experience a mixed up, distorted, or outright false memory. Although these types of memory mix-ups can happen to anyone, because frontal lobe function declines as we age, false memories are more likely to occur to older adults. You can reduce false memories by paying close attention to the details of information when you are learning them and trying again to picture as many specific details as you can when you are retrieving the information.
Semantic memory in normal aging
Most healthy older adults experience some difficulty retrieving people’s names or the titles of books or movies. There are two reasons for this difficulty. The first is their frontal lobe dysfunction. It is your frontal lobes that help you search through your stores of semantic knowledge to retrieve the specific information you’re looking for. So, because of frontal lobe dysfunction, it may be more difficult for older adults to retrieve any type of knowledge. But why are people’s names specifically difficult for older adults? We believe it is likely related to the shrinkage that so often occurs in aging to the tip of the temporal lobe—the very place where the names of people are usually stored. One way to improve your retrieval of people’s names is to think about other things you know about the individual: their occupation, hobbies, family, appearance, etc.
Andrew Budson is a neurologist. Elizabeth Kensinger and Daniel L. Schacter are psychologists. They are authors of Why We Forget and How To Remember Better: The Science Behind Memory.