Memory Loss - Plaques or Genes?

Alzheimer like plaques in the brain may be more important to memory loss than genetic risk

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) Plaques in the brain and some genes have been linked to risk for dementia or Alzheimer’s Disease (AD). A recent study compared the effects of plaques and genes on memory.

The study found in healthy older adults, those with more plaques had more memory loss over an 18 month period. Genetic risk factors were not as big an influence on their memory.

Doctors may be able to use this information to help diagnose AD.

"Ask your doctor about your Alzheimer’s risk."

Researchers in Australia, led by Yen Ying Lim, Master of Psychology, at the University of Melbourne, enrolled 141 elderly people who were healthy and did not have any loss of memory or thinking skills.

At the start of the study, they did brain scans, genetic testing and memory tests.

The brain scans were used to look for the level of beta-amyloid build-up in the brain.

The protein beta-amyloid groups together to form plaques in AD. These plaques are thought to interrupt brain function in ways that affect thinking and memory.

They also did a genetic test to see who had the APoE4 gene. APoE4 is a gene known to put people at greater risk of developing AD.

Eighteen months after the scans and initial testing, all the participants had another memory test.

They found that higher amounts of beta-amyloid in the brain were linked with more loss of memory skills over the 18 months.

The APoE4 gene was linked with some decline in visual memory, but the relationship between beta-amyloid and memory loss was stronger.

The authors concluded that the build-up of beta-amyloid is more influential in memory decline than the APoE4 gene.

However, this study only looked at an 18 month time frame. The influence of genes may be different over the long-term.

Also, this study was conducted in people who did not have AD.  The influences of genes and beta-amyloid in people already suffering from AD may different from those who do not have AD.

This study was published on October 15 in Neurology.

The study was funded by multiple sources, including the Australian Commonwealth Scientific Industrial and Research Organization, the National Health and Medical Research Council and the Dementia Collaborative Research Centres.

One of the authors on the study reports affiliations with CogState Ltd., the company that provided the CogState battery of tests used in this study. Other authors report financial links to multiple pharmaceutical companies.

Reviewed by: 
Review Date: 
October 11, 2012
Last Updated:
October 18, 2012