By Christine Haran
While many people over 60 say they have "senior moments" when they forget a neighbor's name or spend 10 minutes looking for eyeglasses that are perched on top of their head, most age-related forgetfulness doesn't significantly interfere with one's day-to-day life. Memory loss and confusion due to Alzheimer's disease, however, can wreak havoc on the lives of the people it affects and their loved ones.
But how can one distinguish between age-related forgetfulness and the early signs of Alzheimer's disease, a progressive form of dementia that affects an estimated 4.5 million older Americans? Below, Ronald Petersen, MD, director of the Mayo Alzheimer's Disease Research Center in Rochester, Minn., discusses the signs and symptoms of Alzheimer's disease and how doctors, patients and their families can work together to ensure an early and accurate diagnosis.
Is memory loss a part of normal aging?
Some forgetfulness is common and felt to be a part of normal aging. If people forget incidental items—information that one doesn't spend a lot of attention trying to remember—that's probably normal. That includes things like "Where did I put my checkbook?" and "Where are my reading glasses?"
Another common forgetfulness of aging is having trouble coming up with names of people such as acquaintances you run into unexpectedly. You may struggle for their name for a few minutes and then say, "Oh, of course, that was Bill."
However, when people start to indicate that they are forgetting information that is important to them, that's a concern. This applies to something that they actually have spent some effort trying to remember such as a doctor's appointment.
Forgetting an appointment, as an isolated event, is not necessarily abnormal. But if you look back and see that you also forgot to meet your friends for lunch or to go to a committee meeting, you might have a pattern. And if people who know you well are starting to notice that you're forgetting information that you formerly would not have forgotten, then this matter deserves further attention.
What about people who were always forgetful?
Some of us are characterized by our spouses as being absentminded, and, if that's been a lifelong pattern, then that's not too worrisome. However, if a spouse or adult child or good friend notices a change in your thinking ability and your forgetfulness, then that may warrant attention.
What are symptoms of Alzheimer's disease other than memory loss?
Outside of the memory domain, you may have changes in the ability to carry out your daily functions. So if you formerly handled the finances for the family—you took care of the checkbook, you paid the monthly bills, you did the taxes or prepared the material for your tax preparer—and now you're starting to have difficulty, that might be significant.
Loss of navigational skills is another symptom. We all take it for granted that we can get around town, we know how to get to the grocery store, to the golf course or the restaurants. But if you're starting to get a little disoriented and getting lost in previously familiar environments, that would be a sign there are cognitive difficulties associated with Alzheimer's.
People may also have a change in their ability to concentrate on events. So, formerly, you could sit through a two-hour movie without a problem or watch television programs, or read a novel. And you just don't do that anymore.
How do doctors make the assessment?
There's a fairly standard approach to evaluating somebody for a cognitive impairment that might lead to a diagnosis of dementia or Alzheimer's disease. Generally, we start out with the history. That is, we interview the person and ask questions about their behavior and forgetfulness and ask them to give examples.
We ask how long has this been going on. "Have you been noticing this for days, weeks, months or maybe even years? Has it changed? Has it actually changed your functional activities now? Are you now altering your daily routines or your behaviors because of these cognitive changes?"
Equally important to the patient's history is that of a collaborative source who can also reflect on that person's cognition and behavioral changes. So interviewing a spouse, adult child or good friend is invaluable and you pretty much ask the same kinds of questions.
What does the medical evaluation involve?
Once the doctors have established a feeling as to whether this might be a serious problem or not, they conduct an examination. A medical examination is done to make sure the heart and lungs are OK. A neurologic examination is performed to make sure that there's nothing else in the nervous system going on like a stroke or Parkinson's disease or evidence for a brain tumor.
Physicians will also do a mental status exam. I'll do a little brief exercise in the office where I'll say, "What's the date? Where are we? Try to remember these numbers. Here are a few words to remember." I'll have them do some calculations.
After that, we might launch into laboratory testing, looking for medical causes of the change in thinking. So we'll do blood counts, thyroid function, vitamin B12 level, which can have an impact on thinking and memory. We may do an imaging study such as a CT scan or an MRI scan of the brain to see if there's any evidence of a stroke, tumor, blood clots. Or we will see if is there more shrinkage in the brain than we would like to see for their age, implying that there might be a degenerative process.
There are a variety of other tests that we might pursue, depending on the medical history of the person. Then we put all this information together and we come up with a judgment as to whether this person is, in fact, experiencing a change in daily activities as a result of cognitive problems. We then determine how severe it is and try to sort out what kind of dementia it is.
How does one distinguish between Alzheimer's and other forms of dementia?
In people in their late 60s, 70s and 80s, dementias are usually degenerative; they come on slowly and insidiously. And anywhere from 50 percent to 75 percent of all dementias of aging are due to Alzheimer's disease.
But there are some degenerative dementias other than Alzheimer's disease. One is called dementia with Lewy bodies, which is seen in the brains of people with Parkinson's disease. People with this condition may have daytime visual hallucinations and a particular type of sleep disturbance where they act out dreams in the middle of the night. Although their information-processing speed is slow and their ability to navigate in the environment is impaired early, memory is relatively spared. In contrast, memory is the hallmark of the early onset of Alzheimer's disease.
The next most common form of dementia is so-called frontotemporal dementia. The frontal and the temporal lobes of the brain are involved in somewhat different behaviors in cognitive function than the parts of the brain that Alzheimer's affects. So people with this dementia may engage in inappropriate behavior that they never would have done earlier in life had their brain not been affected. For example, they might say inappropriate things in social settings, like comment on the appearance of someone.
There is also the more rare, abrupt onset of so-called vascular dementia. So if you said "Oh, my cognitive problems started last Wednesday at 3 pm," that would imply there was a stroke or blood clot or other event that caused the problem. That would not be consistent with the degenerative picture of most dementias.
Is there a test for Alzheimer's?
While there is no definitive test for Alzheimer's disease while the patient is alive—an autopsy is the final way we get the answer—doctors usually get the diagnosis correct.
There is a blood test called apolipoprotein E that has been touted as being useful in helping sort out the underlying cause of the dementia. [This test looks for proteins produced by the ApoE gene, which has been linked to Alzheimer's.] But some rather large studies have shown that this only augments the clinician's opinion a few percentage points. And those tests are imperfect because they don't necessarily pinpoint this as being Alzheimer's disease or not; they just alter the probability that it's Alzheimer's disease.
Are there any early warning signs?
We've been doing a lot of research on the notion of mild cognitive impairment. I think the broadest way to understand this concept is to say that this is the earliest form of any type of dementia. It's about moving the threshold for detection back to try to pick up a condition before it evolves.
We've developed criteria for this mild cognitive impairment condition. Usually, people are aware their memory's not as good as it used to be. Number two, when we actually measure their memory performance, they are, in fact, performing lower than other people of their same age and education. Yet, when we measure their other cognitive functions and daily activities, they're normal.
So if you use these criteria, you can define a group of people who do have features of mild cognitive impairment. And then, if you follow them over subsequent years, they tend to progress to meet the criteria for Alzheimer's disease at a rate of maybe 10 to 15 percent per year. And that's in contrast to people of the same age who who will become demented or meet criteria for Alzheimer's disease at a rate of only 1 to 2 percent per year.
Do you think people who have a little forgetfulness should get checked out?
I think so. I'm not trying to alarm everybody because if you ask a group of 65-year-old-plus individuals, how many of you are having difficulties with your memory, three-quarters of the room will raise their hand. So you don't want to frighten everybody and say, "Oh, my gosh, you've got this mild cognitive impairment, so you're going to develop Alzheimer's disease in three to five years."
But, at the same time, if you think about the worrisome types of forgetfulness versus the more benign types of forgetfulness, I think you can sort out who should be evaluated.
At what point would you initiate treatment?
The Food and Drug Administration (FDA) has only approved medications for mild to moderate and, more recently, moderate to severe Alzheimer's disease. So, technically, if you follow FDA guidelines, you should only use the medications when people meet criteria for Alzheimer's disease.
In fact, clinicians have some latitude, and, if they feel that the person is on the road to Alzheimer's disease just not quite there yet, they may explain to the risks and benefits to the patient and offer them a drug for Alzheimer's disease.
What is your advice to someone who's concerned that they or someone in their life has Alzheimer's disease?
If you are concerned about yourself or about your loved one, you should probably pursue an evaluation with your local doctor and start the ball rolling because sometimes there are treatable reasons for the problems they are experiencing.
For example, depression can alter our ability to think and concentrate, so it can affect memory function and that's a treatable entity. Sometimes there are medical conditions that may cause a worsening of thinking and those may be treatable or have treatable components. Maybe it's a side effect of medications that you've been taking for other health problems. It might be due to a medical illness or some physical aging factor such as vision loss. I think it's the job of the clinician to try to tease those apart.
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