Study Reveals That Alzheimer’s Could Be Detected 18 Years Prior to Diagnosis

The objective of a recent study spearheaded by Kumar Rajan and his colleagues at Rush University Medical Center was as follows: “To examine the relation of performance on brief cognitive tests to development of clinically diagnosed Alzheimer disease (AD) dementia over the following 18 years in a sample of African Americans and European Americans.”

“None of the study’s participants had dementia before the study began.”

What can simple tests tell us about Alzheimer’s?

In other words, Rajan and his colleagues were hoping to discover whether or not Alzheimer’s could be detected sooner than what had been previously thought (10 to 12 years prior to symptoms). Their findings were remarkable, to say the least.  

Though lengthy, the study’s methods were relatively simple: Rajan and his colleagues tracked 2,125 people for 18 years. The average age of the study’s participants was 73. None of the study’s participants had dementia before the study began.

How the participants were tracked was equally simple but very telling. Every three years, Rajan and his colleagues would administer mental skills tests. Once completed, the test results would be compared to previous tests. And what did the study reveal?

“…a decline that proved to be consistent throughout the study.”


Of those 2,125 participants, 21% went on to receive an Alzheimer’s diagnosis. That in mind, the test scores of this particular group told an interesting story: a decline in scores could be detected as far back as from cognitive test #1 to cognitive test #2; a decline that proved to be consistent throughout the study.

What this means is that Alzheimer’s may be able to be detected as early as 18 years before diagnosis based on the symptoms. But, as Rajan acknowledges, this one study is not enough evidence for the 18-year mark to be conclusive. More research is needed; if nothing else, this particular study shows that there is much more to learn about the disease. Nonethless, if detection 18 years early is possible, just think of what doctors will one day be able to do in order to intervene and alter the trajectory of the disease.  

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