Early Signs of Alzheimer’s

Alzheimer's changes the brain before any symptoms appear

(RxWiki News) New technologies and guidelines may help scientists better understand the Alzheimer’s Disease (AD) brain before symptoms appear, which may lead to earlier detection in future generations.

Guidelines for changes in the brain, including increased beta amyloid, may help researchers understand the preclinical brain changes in AD. 

Imaging technologies may help to show doctors and researchers how the brain changes in early AD.  However, brain scanning technologies are costly and are currently limited in everyday practice.

"Discuss any memory problems with your physician."

The National Institute on Aging (NIA) published categories about three stages of preclinical AD brain changes. First, beta amyloid, a substance that groups together and forms plaques, increases in the brain. The second stage includes loss of brain matter in addition to increased beta amyloid.

The third stage includes subtle cognitive changes in addition to the signs of stages one and two.

All of the NIA categories are designed to set up a continuum of brain changes that are occurring in AD before any real signs of the disease are present – before cognitive and memory impairment.

David Knopman, MD, of the Mayo Clinic set out to test the categories in actual patients. He used MRI to image the brains of 296 people and tested their cognitive abilities.

After the initial scans and tests, patients were classified as being in NIA stage 0 – not on the scale – or in NIA Stage 1 through 3. They tracked the patients for one year. Over the year of follow up, 10% developed mild cognitive impairment (MCI) and none developed AD during the year.

The number of people developing cognitive impairment was higher for people who were initially categorized into higher NIA stages. Eleven percent of people in stage 1, 21 percent of people in stage 2 and 43 percent of people in stage 3 advanced to MCI during the one year follow up.

Overall, Dr. Knopman’s research shows that the NIA stages may be good predictors of risk for AD. The researchers noted that more research is needed to define the stages, like what is considered an increased amount of beta amyloid (stages 1 - 3), how to assess subtle cognitive changes (stage 3) and to understand these stages in terms of long-term outcomes.

A recently approved imaging drug and related technology may also help with detecting beta amyloid in the brain. Amyvid uses an element that binds to beta amyloid so it can be imaged in the brain using positron emission tomography (PET) scans.

This drug allows doctors to more accurately diagnose AD and may be used in early detection if it becomes more cost effective.

Both MRI and Amyvid PET scans cost approximately $3,000 to $5,000, so they are currently only used in circumstances where other causes of dementia need to be ruled out. 

However, the new information learned through the honing of these technologies may lead to improved detection and treatment strategies in the future. 

Dr. Knopman’s study was funded by grants from the NIH and published in May in Neurology. Authors on this study report affiliations with Bristol-Meyers Squibb, Eli-Lilly, and Bayer, among others. The FDA approval for Amyvid was reported in April.

Review Date: 
June 3, 2012