New Diagnostic Algorithm Distinguishes Alzheimer’s Disease From Primary Tauopathies

It is now simpler to differentiate between primary tauopathy and Alzheimer’s disease thanks to a novel biomarker.

Patients with rare and specialized conditions, such as primary 4-repeat tauopathies, often present at academic hospitals since private practice doctors may rarely encounter them. Primary 4-repeat tauopathies are associated primarily with movement abnormalities, but diagnosing them can be challenging because their symptoms often overlap with those of Alzheimer’s disease. Researchers at LMU University Hospital have developed a new diagnostic algorithm that allows for accurate differentiation between these two illnesses using data from positron emission tomography (PET) scans.

Improved Diagnostic Precision with New Algorithm

“The new diagnostic algorithm we developed allows physicians to differentiate with greater precision between Alzheimer’s disease and primary tauopathies, facilitating earlier and more accurate diagnoses and supporting personalized treatment strategies,” says principal investigator Professor Matthias Brendel, acting director of the Department of Nuclear Medicine and member of the SyNergy Cluster of Excellence. The results of this study have been published in the journal of the Alzheimer’s Association, Alzheimer’s & Dementia.

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Detecting Tau Protein Aggregates

Both Alzheimer’s disease and primary 4-repeat tauopathies are characterized by large pathological aggregates of the tau protein in the brain. For decades, tau proteins have been detectable for Alzheimer’s disease through cerebrospinal fluid (CSF) analysis. Recently, researchers have developed radioactively labeled substances (tracers) that accumulate at tau aggregates after injection, making them visible on PET scans.

“Our new study shows that tau can be identified with the novel tau PET tracer even in 4-repeat tauopathies — but not in the cerebrospinal fluid, rather in very specific areas of the brain known as the subcortical brain regions,” explained Roxane Dilcher, lead author of the study.

Integrating PET Signals and Biomarkers

The PET signal is just one component of the new diagnostic process. The researchers have also identified new biomarkers indicating the presence of a 4-repeat tauopathy. “Diagnosis becomes highly effective when we analyze a combination of cerebrospinal fluid tests, innovative biomarkers, and PET signals in the subcortical regions,” says Matthias Brendel. “This approach allows us to recognize a 4-repeat tauopathy with a high degree of certainty.”

Advancements in Diagnosing Rare Tauopathies

“Primary 4-repeat tauopathies are currently diagnosed almost exclusively using clinical criteria, without specific biomarkers that enable conclusive diagnosis,” says co-senior author Dr. Nicolai Franzmeier, also a member of SyNergy. “The establishment of biological definitions and corresponding biomarker workflows will significantly advance the research field.”

(WITH INPUTS FROM ANI)

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