How to Read the News: Part 1 of 5

Contributed by: Dennis Fortier, President, Medical Care Corporation
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The purpose of the Brain Today blog is to distill the daily news about brain health and help the public understand the essential meaning of each article. Through time however, I have found myself clarifying the same themes over and over again. Five of these themes are explored in this five-part series “How to Read the News About Alzheimer’s and Dementia”.

How to Read the News About Alzheimer’s and Dementia - Part 1  
Be Aware of the Author’s Definition of Alzheimer’s Disease

A major source of unintended confusion about Alzheimer’s disease (AD) is the inconsistent definition of this disease from one article to the next. In many instances, the author uses a definition that the reader might not fully understand. I explored this problem more fully in an earlier post (When Does Alzheimer’s Disease Really Begin?) but I will summarize it succinctly here.
The problem is that research scientists think about the disease in terms of pathology and speak about it in those terms. Given the long underlying process of amyloid accumulation in the brain, they contend that AD begins decades prior to the first clinical symptoms of memory loss.

Physicians, on the other hand, use a strict clinical definition of the disease stating that AD begins when the underlying pathology (amyloid accumulation) has caused enough brain damage to render the patient demented. In this scenario, the disease begins many years after the first clinical symptoms.

Most lay-people default to a symptom-based understanding and consider the disease present when the symptoms first appear. This occurs at some mid-point between the other two perspectives.

When you read the news, it is important to understand the potential for confusion in this regard. Here are a few of the many examples of how confusion arises:

• If an article says that a drug is useful in treating early-stage AD, you should be careful to understand what the author means by “early-stage”. They might mean "30 years prior to symptoms" or they might mean "the point at which the patient becomes demented". Unfortunately, such claims often breed false hope and are usually not meaningful to those recently diagnosed with AD because, by all definitions, we rarely diagnose the disease early.

• When you read that AD is difficult to distinguish from normal aging, be aware that this is true for some definitions of AD but not for others. There is certainly a clear distinction from normal aging once clinical symptoms appear.

• When you read about mild cognitive impairment (MCI) and that it may or may not convert to AD, don’t be accidentally misled. Focus on any information indicating the cause of the MCI. If it is AD pathology, then scientists would agree that the patient already has the disease while physicians would argue against an AD diagnosis until the symptoms progress to dementia.

Keep in mind these multiple definitions for AD that are commonly used in the press and it will help you to avoid misleading conclusions about otherwise clear news items.

Here are the links to each other part of this series:
Part 2 of 5: Don't be Mislead by Data on Treatment Efficacy
Part 3 of 5: Common Assertions about Diagnostic Accuracy Hide Truth
Part 4 of 5: The Term "Dementia" Cannot be Interpreted Loosely
Part 5 of 5: "No Cure" Not as Bad as it Sounds