Memory loss as you age is natural, but when does it become a serious issue? Guest writer Dr. Allan Ropper, author of Reaching Down the Rabbit Hole: A Renowned Neurologist Explains the Mystery and Drama of Brain Disease, explains.
Beginning in our early forties, almost everyone begins to notice that names are harder to recall, and that the details of past events have to be replayed in the mind in order to keep all of them straight. This is a contrast to the effortless way in which memory “stuck” like an insect on flypaper when we were younger. It becomes more noticeable in the fifties and for most people the sixties bring a need for us to have an internal conversation to get straight all the facts and people’s names of a previous encounter.
Curiously, very distant past events, such as the name of your first grade teacher, are not a problem to recall. This discrepancy between recent and long ago memory has been termed “Ribot’s law” (pronounced Ree-bow) after the French doctor pointed out that any theory of brain function would have to explain this aspect of memory.
So, when does memory loss signify something serious, like dementia? Generally, when forgetting things begins to consistently disrupt daily life. Here are some of the common types of memory lapses that I hear in the office that do not disrupt daily life and are not signs of dementia: “I can’t find my car keys” (substitute, anything you like for keys, except maybe your spouse); “I went into the room and could not remember why I went there”; “I called my new son-in-law by the wrong name and can’t to stop doing it”; “I have a lot of trouble getting back to my car in the parking lot”; “I forgot the name of my first grade teacher but it came to me later.”
See also: How To Remember Names
Maybe you have noticed that if you’re not paying attention when you put down your keys in the first place, you can’t set it down in memory and you will be unable to recall it later. This is obviously not a problem with the brain’s memory circuits. Furthermore, the lost location, name or word comes to you later so it never really vanished in the first place. In other words, both the encoding and the recall of experiences is highly dependent on attention and alertness at the time they occur, and these are functions that decrease not just with age but also with distractions, depression, multitasking, kids yelling in the background, preoccupation with worry, and so on. These problems are not dementia.
What is distinctive about MCI is a serious inability to learn and retain new facts, a defect that can be tested in the office with quick pen and paper testing.
Occupying a place between the benign memory disorder of aging and full on dementia is an entity called mild cognitive impairment, or MCI. The individual notices a steep decline from previous memory function, as appointments, birthdays and the names of well-acquainted people are lost. What is distinctive about MCI is a serious inability to learn and retain new facts, a defect that can be tested in the office with quick pen and paper testing. Among the most popular of these tests are the MMSE (mini-mental status exam) and MOCA (Montreal cognitive inventory). Both include tasks of recalling a few words but also venture into drawing and reasoning abilities because dementia often spreads to these problems as well. In the most common dementia, Alzheimer disease, what stands out is the ability to repeat a string of words, but not to recall those words minutes later. Being able to repeat them right away indicates that attention is good but the lack of retention shows that the memory circuits are selectively at fault. In MCI, perhaps one of four words cannot be recalled.
See also: 4 Tips for Alzheimer's Prevention
And here is an interesting observation from my own practice—whereas most patients with enough insight to complain that their memory is bad do not have dementia (they are nervous, or depressed, particularly if there is worry because a family member has Alzheimer’s disease or they have read something about memory on the internet). MCI patients are also aware of the problem, and if dementia takes over, they again minimize or are oblivious to their poor memory, finding excuses for not knowing the date, for example, because they no longer read the paper or ”don’t pay attention to those things.”
This highlights another aspect of memory that Ribot pointed out—the loss of ability to learn new things—anterograde amnesia, is inextricably tied to a comparable amount of difficulty in recalling things—retrograde amnesia. The almost obligatory linkage between these two aspects of memory is true whether the problem is chronic, as in dementia, or acute, as in concussion. (As an aside, the inability to recall one’s own name happens only in the movies and in bizarre tabloid news stories, is complete baloney. Only when dementia has reduced someone to being mute does a person lose his or her own identity).
The most dramatic linkage between anterograde and retrograde memory is in the peculiar state called transient global amnesia in which people behave completely normally but, at the same time are unable to comprehend how they got where they are and no amount of telling them fixes this until the spell clears. Along with this lapse of being unable to retain new information, there is a window of retrograde amnesia spanning days or weeks that later recovers. And, by the way, they never forget their own name. You can read about this in recent book Reaching Down the Rabbit Hole (St. Martin’s Press) or more technically, in the textbook of neurology I wrote with my colleagues Principles of Neurology (McGraw Hill).
When memory trouble reaches the point of family members and friends noticing something consistently wrong, is there serious medical worry. By this time, the person with memory trouble turn to family or friends to get the answers to questions about the date, who is the president, what is the name of the hospital or doctor, or even whey they came to the doctor?
The progression from MCI to dementia, and the development of Alzheimer disease, is highly dependent on genetic factors, none of which alone determines if a person will develop the disease. The most important of these involves variations of a protein called ApoE. New brain scanning techniques are being introduced that can show the amyloid protein that deposits in Alzheimer’s but even then, there are false positives and negatives. Few people need these scans or the ApoE test to determine if they have Alzheimer’s disease. It becomes apparent when the physician follows the life progression of an individual.
The take home message—most memory trouble is an annoying part of aging or the result of another underlying problem such as distraction, worry or depression, often fixable. Dementia disrupts many aspects of daily life and is rarely subtle. Most people who are aware of—and nervous about—their own declining memory, do not have dementia.
Memory loss and confusion concept images courtesy of Shutterstock.