Having a high amount of beta amyloid or "plaques" in the brain could cause greater memory decline than having the genetic risk factor IAPOE E4 allele--associated with Alzheimer's disease--according to a study published in the Oct. 16 issue of Neurology.
"Our results show that plaques may be a more important factor in determining which people are at greater risk for cognitive impairment or other memory diseases such as Alzheimer's disease," study author Yen Ying Lim, MPsych, University of Melbourne in Victoria, Australia, said in an announcement.
For the study, researchers tested 151 people with an average age of 76 for the APOE gene and had them undergo PET brain scans, as well. The researchers then tracked the group's brain functions over 18 months by using a set of computer-based cognitive assessments based on playing card games and remembering word lists.
The researchers found that people who had more brain plaques at the beginning of the study had a greater decline on the computer-based memory assessments than those who had fewer brain plaques. They also determined that while those with the genetic risk factor also showed greater cognitive decline, carrying that gene did not affect the memory decline associated with the plaques.
"Our finding, that brain plaque-related memory decline can occur while people still have normal memory and thinking, shows that these plaque-related brain changes can be detected and measured while older people are still healthy," Lim said. "This provides an enormous opportunity for understanding the development of early Alzheimer's disease and even a sound basis for the assessment of plaque-targeting therapies."