Alzheimer's Can Now Be Diagnosed 10 Years Before Symptoms.

A new test that promises to identify people developing Alzheimer's disease ten years or more before the first symptoms will soon be available to the public, according to a study published by the Journal of the American Medical Association (JAMA)⁽¹⁾. An editorial that accompanies the article presents it as unconditionally positive. Sadly, close examination shows that is not the case.

The hype claims that the study shows the test provides 100% accuracy in identifying who will develop Alzheimer's dementia within ten years. However, that is not quite what it demonstrated. Rather, the study showed who, among people who are already suffering from significant memory loss, will develop the particular type of dementia called Alzheimer's.

According to the New York Times⁽²⁾, Dr. Steven DeKosky, Dean of the University of Virginia medical school, exclaimed, "This is what everyone is looking for, the bull's-eye of perfect predictive accuracy." Washington University's Professor of Neurology, Dr. John Morris, enthused that the study, "establishes that there is a signature of Alzheimer’s and that it means something. It is very powerful."

Who Benefits?

The push is already on to make this spinal puncture test routine—even though the study has not been duplicated and its sponsor clearly has a strong financial interest in the results.
Currently, there are no drugs that can prevent Alzheimer's disease. There are, though, about 90 drugs being tested to see if they can slow or stop its progression. Naturally, if a study can appear to document that a drug does this, then the manufacturer will have a blockbuster. If a test exists that can predict years in advance who will develop Alzheimer's, then the value of that drug could be multiplied many times over.