By changing how they define Alzheimer's Disease, scientists hope they can better understand how it works and possibly find new treatments.
Some diseases are very easy to define, especially when it involves something physical. For example, chicken pox is defined by the presence of the active virus in your bloodstream and the physical marks associated with the disease.
Other diseases are defined by the presence of certain symptoms, such as various mental health diseases and Alzheimer's is one of the latter. It is defined by people who have certain symptoms.
Some scientists would like to change that for research purposes as NPR reports in "Scientists Push Plan To Change How Researchers Define Alzheimer's."{: target="_blank"}
Scientist's now know there are certain changes to the physical structure of the brain that can be detected in people who currently show none the symptoms traditionally associated with Alzheimer's. Changing the definition of Alzheimer's, would have no impact on how doctors currently diagnose and treat patients.
On the other hand, it would help researchers immensely. If they can conduct studies on people who do not yet have symptoms, they might be able to gain a better understanding of what causes the disease and how it progresses in the earliest stages. That could lead to better treatments or even a cure.
Reference: NPR (April 10, 2018) "Scientists Push Plan To Change How Researchers Define Alzheimer's."{: target="_blank"}