Blood Test Shows Promise for Early Detection of Dementia

By LabMedica International staff writers
Posted on 19 Mar 2025

Image: The blood test could help predict the development of dementia years before symptoms appear (Photo courtesy of 123RF)

Idiopathic REM sleep behavior disorder (iRBD) causes individuals to physically act out their dreams while sleeping. This disorder is strongly linked to a high risk of developing Parkinson’s disease and a related condition known as Dementia with Lewy Bodies (DLB). DLB is a type of dementia that leads to memory and cognitive decline, as well as vivid visual hallucinations and motor difficulties similar to Parkinson’s. Early detection of dementia risk could significantly influence how doctors manage patient care, allowing them to plan ahead and potentially offer more tailored, effective treatments. Now, a simple blood test could offer the potential to predict dementia development years before symptoms manifest in those with this sleep disorder.

Researchers at McGill University (Quebec, Canada) have found that a blood test initially created to detect Alzheimer’s disease could also help identify which iRBD patients are at higher risk of developing Dementia with Lewy Bodies. This test measures two proteins in the blood that are biomarkers for Alzheimer’s. In the study, the researchers followed 150 iRBD patients, taking annual blood samples to test for the biomarkers and tracking their health over time.

Remarkably, the blood test conducted four years prior successfully predicted dementia in nearly 90% of the patients who eventually developed the condition. Published in the journal Brain, the study also suggests that the early stages of Parkinson’s and Alzheimer’s share more similarities than previously recognized. The research team plans to expand the study to evaluate the test’s ability to predict dementia risk in individuals already diagnosed with Parkinson’s disease and in other groups at risk for Dementia with Lewy Bodies.

"Our findings suggest that Alzheimer’s treatments could also be tested in patients with this sleep disorder. Perhaps, if treatments start early enough, Dementia with Lewy Bodies can be prevented,” said first author Dr. Aline Delva.