In a report published in the journal Neurology, researchers suggest that the first biological signs of Alzheimer’s disease may be present as early as 18 years before cognitive declines are revealed, TIME reported. Studies so far had found evidence that the biological processes that cause the mental decline may begin 10 to 12 years before people first notice signs of cognitive decline. But in the most recent report experts say that the disease may actually begin even earlier — 18 years earlier, in fact — than they expected.
In the trial, Kumar Rajan, associate professor of internal medicine at Rush University Medical Center, and his colleagues followed 2,125 elderly people with an average age of 73 and who did not have dementia.
Every three years, the researchers gave the volunteers mental skills tests, and then compared these results over time and found that the group that went on to receive an Alzheimer’s diagnosis showed lower scores on their tests throughout the study period.
Specifically, their scores steadily declined with each test, with each unit that the scores dropped on the cognitive tests equating to an 85-percent increase in the risk of future Alzheimer’s disease.
However, Rajan stresses that the results only link cognitive testing scores on broad, group-level risk, and can’t be used to predict an individual’s risk of developing the disease.
Next, Rajan plans to study whether brain-stimulating activities like crossword puzzles or learning a new language and social interactions can improve the test scores, and in turn slow the time to diagnosis of Alzheimer’s.