Test to detect Alzheimer's disease before symptoms occur

Researchers have developed a test that could help doctors detect Alzheimer's disease eight years before the onset of symptoms.

According to current techniques, Alzheimer's disease, the most common cause of dementia, can only be detected when typical plaques have formed in the brain.

At this point, therapy no longer seems possible. However, the first changes caused by Alzheimer's disease occur at the level of proteins up to 20 years earlier.

"Once the amyloid plaques have formed, it seems that the disease can no longer be treated," said co-author of the study, Andreas Nabers of the Ruhr University in Bochum in Germany.

In patients with Alzheimer's disease, the beta-amyloid protein does not fold correctly due to pathological changes long before the onset of symptoms.

A team of researchers, led by Klaus Gerwert of the Ruhr University in Bochum, managed to diagnose this aliasing with the help of a simple blood test. As a result, the disease could be detected about eight years before the appearance of the first clinical symptoms.

However, experiments have shown that the test was not suitable for clinical applications as it provided a false-positive diagnosis to 9% of study participants.

In order to increase the number of correctly identified Alzheimer's cases, researchers have now introduced the two-level diagnostic method.

To this end, they use the original blood test to identify high-risk individuals. Subsequently, they add a dementia-specific biomarker, tau, to perform additional tests with test participants who initially had a positive diagnosis of Alzheimer's disease.

If both biomarkers show a positive result, the probability of contracting Alzheimer's disease is high, says the study published in the journal Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring.

"With the combination of the two analyzes, 87 out of 100 patients were correctly identified in our study," said Gerwert.