The following is a guest post by Linda Furlini, PhD, who works in the research ethics office of McGill University Health Centre in Montreal.
[Editor’s note: The CBS News video that is the basis for this article is no longer available. The issues raised in the post remain relevant regardless of access to the accompanying video.]
Since the late 1980’s, I have developed a voracious appetite to learn all there is to learn about Alzheimer’s disease because both of my parents at the age of 60 were affected by it, even though neither had a family history of the disease. In the process, I have gathered what has amounted to mountains of disinformation on Alzheimer’s disease. As I perused the many articles I had collected, it became glaringly apparent that, in that quarter century, little has changed: consistent unfounded claims have been made about the latest “breakthroughs,” “discoveries,” and “understandings.” Each claim creating false hope, or worse, harm and confusion. When I reflect on all those bogus claims, I become overwhelmed with frustration, anger and dismay.
So, when I listened to a recent CBS evening news report (June 19, 2012), these feelings returned with a vengeance.
Dr. LaPook presented a new test that could diagnose and predict the occurrence of the Alzheimer’s disease with absolute certainty. During the segment, we meet a man named Alex who undergoes the test. He is described as a scientist and a highly intelligent man, particularly worried about his self-reported cognitive decline in light of the fact that his mother had Alzheimer’s disease. Undoubtedly, this type of worry would resonate with anyone familiar with the ravages of this disease. We are told that this new test, “Would tell him for sure” if he had Alzheimer’s disease. We are then informed that the test result shows “He does not have Alzheimer’s disease.” Recently, the FDA approved florbetapir, a radioactive dye that detects amyloid plaques, a protein in the brain that some scientists theorize play a role in the development of the disease. Through the use of a PET scan, this dye showed Alex’s brain showed no presence of amyloid plaques. We see a visibly relieved Alex.
But what did this test really tell Alex? The test showed that no amyloid plaques were detected, but nothing more. What the test failed to do was to tell Alex that: 1) although he appeared not have Alzheimer’s disease, it was not absolutely certain he was free of the disease; 2) some people who have these amyloid plaques do not demonstrate symptoms of the disease; and 3) it was unknown whether he would develop this disease in the future.
We lack evidence to determine whether the plaques develop before the onset of symptoms or once the disease is already established. Still, we do know enough about the disease to appreciate that although the plaques may be apparent, a person may not demonstrate any symptoms of the disease. We also know enough to realize that the lack of amyloid plaques is not predictive and that the disease may manifest itself in the future. So why not present this information in the CBS report?
Justifiably, patients, families and society are desperate to prevent Alzheimer’s disease, a scourge that many of us will face in this century. In the rush to develop preventative disease drug trials, the NIH added a new phase to their diagnostic guidelines, named “Preclinical Alzheimer’s.” Unreliable and unproven tests to diagnose the disease, such as the one Alex took, will be used to recruit people into these trials. An important question that begs to be asked: how can we trust the drugs that will be developed as a result? What are the ethical implications for those that are determined to have “Preclinical Alzheimer’s” and never develop the disease and, conversely, those whose tests show no evidence, but do have symptoms? For excellent reading on this topic, see Covinsky and Kutschenko.
Alzheimer’s disease is complex, but it is in the pharmaceutical industry’s interest to oversimplify it. Clearly, the test reported on by CBS demonstrates medical progress. But, it should have seriously questioned the value of the test. Instead, unsuspecting, desperate and worried people will be lured into believing more than they should about it and recruited into clinical trials built on uncertainties and ambiguities. Shame on CBS for adding yet more material to my mountains of disinformation, and for failing to address the need for better scientific research.
Covinsky, K. (2011). Caution on Diagnosing Preclinical Alzheimer’s Disease. The Hasting Centre Report,
Kutschenko, L. (2012). Disgnostic misconceptions? A closer look at clinical research on Alzheimer’s disease. Journal of Medical Ethics, 38, 57-59