Mistakes on memory and thinking tests could be early warning signs of Alzheimer’s disease, according to new research.
The errors could serve as a “red flag” for the debilitating disorder as much as 18 years before Alzheimer’s can be diagnosed medically, according to researchers from Rush University Medical Center in Chicago.
The study was published June 24 in the online edition of Neurology, the academic journal of the American Academy of Neurology.
“The changes in thinking and memory that precede obvious symptoms of Alzheimer’s disease begin decades before,” study author Kumar Rajan, PhD, said in a news release from the American Academy of Neurology.
“While we cannot currently detect such changes in individuals at risk, we were able to observe them among a group of individuals who eventually developed dementia due to Alzheimer’s,” Rajan said.
For the study, researchers administered memory and thinking tests to 2,125 white and African-American adults in the Chicago area. The adults had an average age of 73, and took the tests every three years over an 18-year period. None had an Alzheimer’s diagnosis when the study began.
Early warning signs
During the course of the study, 23 percent of African-American subjects and 17 percent of white subjects developed Alzheimer’s. Those who scored the lowest on the memory and thinking tests were at highest risk to develop the disease.
During the first year of the study, people with lower test scores were about ten times more likely to be diagnosed with Alzheimer’s disease than people with higher scores. The odds increased by ten for every standard deviation that the score was lower than the average.
Experts have long known that changes in the brain that lead to Alzheimer’s begin years before symptoms ““ problems with memory, language and thinking ““ become apparent. The results indicate that even subtle declines in cognitive abilities affect future risk of Alzheimer’s, Rajan said.
“A general current concept is that in development of Alzheimer’s disease, certain physical and biologic changes precede memory and thinking impairment,” he said. “If this is so, then these underlying processes may have a very long duration. Efforts to successfully prevent the disease may well require a better understanding of these processes near middle age.”
