The new method aims at the definition of Alzheimer’s disease to find disease early


New way of defining Alzheimer's aims to find disease sooner

The government and other scientists propose a new way to define Alzheimer’s disease based on biological characteristics, such as changes in the brain, not the memory loss and other symptoms of dementia, which are used today.

The move is aimed at improving the research using more objective criteria, such as brain imaging to select patients for the study and to enroll them earlier in the course of the disease, when treatment may be more likely to help.

But it’s too early to use these images and other tests in routine care because they have not been tested for this, experts stress. Now doctors continue to rely on the tools they have long been used to assess thinking skills to diagnose most of the cases.

Regardless of which tests are used for diagnosis, the new definition will have a striking effect: more and more people are considered to be Alzheimer’s disease because biological markers can appear 15 to 20 years before symptoms.

“The numbers will increase dramatically,” said Dr. Clifford R. Jack Jr., Mayo clinic brain imaging specialist. “There are a lot more informative for normal people who have pathology in the brain, which will now be regarded as Alzheimer’s disease.”

He led a group of experts working with the Alzheimer’s Association and the National Institute on aging, updated guidelines on the disease, published in Alzheimer’s & dementia: the journal of the alzheimer’s Association.


About 50 million people worldwide suffer from dementia and Alzheimer’s disease is the most common form. In the U.S. about 5.7 million Alzheimer’s in its current definition, which is based on memory problems and other symptoms. Approximately one third of people older than 70 years who do not show any problems of thinking, actually the brain signs that indicate Alzheimer’s disease, Jack said.

There is no cure — contemporary medicine, such as tablets and Namenda just temporarily ease symptoms. Dozens of hope for the treatments have failed, and doctors believe that one of the reasons may be that the studies involved patients after too much brain damage has already occurred.

“By the time that you have a diagnosis, it’s very late,” said Dr. Eliezer Masliah, head of neurology at the Institute on aging.

“What we realized that we needed to go earlier and earlier and earlier,” just as the doctors found in the treatment of cancer, he said.

Another problem: as many as 30 percent of people that fall in studies of Alzheimer’s disease based on symptoms, not actually have the disease — they had other forms of dementia or even other medical conditions. It does not give an accurate picture of potential treatment may help, and the new target definition to improve the selection of patients with brain scans and other tests.


Many other diseases such as diabetes, has already been determined by measurement of biomarkers, one of the objective indicators such as the level of blood sugar. It is not possible to Alzheimer’s disease a few years ago, when brain scans and cerebrospinal fluid tests were developed for this purpose.

They measure certain forms of two proteins — amyloid and Tau — is a form of plaques and neurofibrillary tangles in the brain tissue and signs of nerve injury, degeneration and shrinkage of the brain.

The guidelines spell out, use these biomarkers for a spectrum of mental decline, beginning with early changes in the brain through mild impairment and Alzheimer’s dementia.


People may be concerned and want these tests for themselves or family members now, but Jack advises: “don’t worry. No proven treatment.”

You could find a doctor willing to order them, but in cerebrospinal fluid of multiple invasive tests and brain scans can cost up to$ 6,000. Insurance usually does not pay because they are considered experimental outside of the study. A large study whether medicare should cover them, and when.

Any person with symptoms or a family history of dementia, or even healthy people are concerned about the risk, you can consider enrolling in one of the numerous studies conducted.

“We need more people in this pre-symptomatic stage”, to see if treatment can help to prevent a fall, said Masliah.

Marilyn Marchione can be followed on Twitter

The associated Press-the Department of health and science receives support from the Department of medical Institute of Howard Hughes science education. AP is solely responsible for all content.


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