n every nation where life expectancy has increased, the incidence of Alzheimer's disease has increased as well. Each year, approximately 360,000 new cases are diagnosed in the United States alone, and still there is no cure. But methods of diagnosing and slowing the disease have vastly improved over the past twenty years. Below, two experts in Alzheimer's research and treatment offer an introduction to the disease.
What is Alzheimer's disease?
NORMAN RELKIN, MD: Alzheimer's disease is the leading cause of dementia in the elderly, dementia being defined as a decline from a previously attained state of cognitive accomplishment that's sufficiently severe to interfere with daily life. By definition, dementia also has to be progressive, and Alzheimer's disease is slowly progressive, often over about a decade.
How widespread is this problem?
PETER DAVIES, PhD: All over the Western world, the disease appears to have about the same incidence, which is approximately six to seven percent of people over the age of sixty-five, and that number may be as high as thirty to forty percent of people over the age of eighty-five.
We've heard a lot more about Alzheimer's over the last decade or two. Is that because the population is aging?
PETER DAVIES, PhD: Oh, most definitely. At the turn of the century, life expectancy was only about sixty years. And Alzheimer's disease is very rare prior to age sixty.
What are the first symptoms of Alzheimer's disease?
NORMAN RELKIN, MD: Alzheimer's is called an 'amnestic dementia', because in the majority of cases, the first symptom is forgetfulness. It's a particular kind of forgetfulness. It's very, very rapid, such that something that a person has heard will be forgotten moments later. That leads to repetitiveness in conversation, and a tendency to forget day-to-day types of activities.
You're talking about short-term memory?
NORMAN RELKIN, MD: It is short-term in the initial stages, to a greater degree than remote, autobiographic memory. But as the disease progresses, most areas of memory become involved. The initial symptoms, though, tend to be confined to the recently learned things.
But not only memory is affected, and I think that one very characteristic feature of the disease is a loss of insight. A person who has suffered a stroke or another form of brain disease might recognize that they're having a problem, but the typical patient with Alzheimer's disease doesn't know, and will not recognize that they're becoming ill. They generally have to be brought to medical attention as a consequence.
Any other symptoms that people should look for?
PETER DAVIES, PhD: I think it's important to remember that we all are forgetful. I'm notorious for losing my car keys and my coffee cup and my glasses. That's not the kind of forgetfulness we're talking about. It's asking you the same question four times in a row within a five-minute span of time, because I simply can't remember the answer you gave me. This is much more typical of the Alzheimer patient.
Of course, as Norman said, the impairment of other activities is also noticeable. Failure to balance a checkbook, when you've done this all your life. Forgetting important issues, things that you do every day. That's when you start looking for medical attention.
What does a doctor look for? Once the signs have been recognized, are there any tests that can tell you that Alzheimer's is the right diagnosis?
NORMAN RELKIN, MD: It used to be said that Alzheimer's couldn't be diagnosed during life, but certainly in recent years that view has changed. We now view the patterns of mental disturbance that occur in Alzheimer's disease as recognizable. So, actually, the mainstay of diagnosis is not high technology or laboratory tests, but a skilled examiner who interviews both the patient and a caregiver, maybe a friend or a relative, to corroborate what history they get from the individual.
Often one of the biggest clues is an incipient dementia, or the patient themselves not being able to convey their own medical history. Once the history has been collected, then it is a matter of performing some kind of a mental status examination. It's not always the case that a clinician has time to do a full and complete assessment of a patient's thought processes, but they do have to establish that the person has impairment which goes beyond day-to-day, normal forgetfulness.
Once that's been established, they'll want to look for other potential contributing factors, the most common being medication-induced changes in cognition, and affective changes such as depression, which can often masquerade with symptoms of memory loss very similar to Alzheimer's, but can be distinguished by a good clinician.
But there are other, more dangerous causes of dementia, like tumors and vascular problems...are these possibility routinely checked?
NORMAN RELKIN, MD: It's checked when it's deemed necessary from the standpoint of the patient's presentation. But testing can be overdone, too. Again, in the old days, we were taught that dementia was a matter of diagnosis by exclusion. You would rule out everything, and what you were left with, you would consider to be Alzheimer's.
We take a more direct and informed approach now, and we do the tests that are appropriate to the patient's particular presentation. If they have symptoms that are suggestive of a brain tumor, then by all means brain imaging would be indicated. But there are some cases in which that type of an evaluation may not be necessary to come to a diagnosis of probable Alzheimer's.
What are some of the potential causes of this disease?
PETER DAVIES, PhD: Clearly, the disease is inherited in a very small number of cases, probably two percent. In ninety-eight percent of cases, however, we don't know what the cause is.
I don't think there is a single theory that would explain the cause of the disease. I think where the progress has been recently has been in understanding the path that the disease takes. The nature of the initiating event is really still unknown. We don't know why the disease begins in one person at age forty, in another person at sixty-five, and in another at eighty-five. There are multiple factors.
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