PUB_General Biomarkers guide

The guide to

Alzheimer's biomarkers

What are biomarkers?

Blood-based biomarkers for Alzheimer's

Diagnosis & disease progression

narration

What's a biomarker?

Blood tests for biomarker proteins

Biomarkers are measurable, biological characteristics that signal whether things are normal or abnormal in the body.

Images from retinal scans

In the case of Alzheimer's disease, biomarkers might be present in the blood, the eye, or even detectable in someone's gait or speech patterns. Detecting and measuring them can help identify Alzheimer's-related brain change even before symptoms ever appear.

Apps that assess vocal signatures

narration

Alzheimer's protein biomarkers

The most commonly referenced biomarkers for Alzheimer's are two problematic proteins: beta-amyloid and tau.

These can be evident in the blood or cerebrospinal fluid. Understanding these levels can aid early detection and monitoring of disease — but they're signals, not stand-alone diagnostic tools. If a biomarker is present, a full clinical evaluation is still necessary to confirm an Alzheimer’s diagnosis.

narration

read more

Alzheimer's biomarkers: Beta-amyloid

Beta-amyloid proteins are peptides in the brain that do important work for our synaptic plasticity and memory function. But they are also one of the key biomarkers for Alzheimer's.

• The first "red flag": Build-up begins more than a decade before Alzheimer’s symptoms appear.

• Not a guarantee: Not everyone with beta-amyloid plaques develops Alzheimer’s.

• Early diagnosis: Advanced tests can detect these plaques before symptoms, identifying those at risk.

• Supporting data: If someone shows Alzheimer’s symptoms, plaques can help confirm the diagnosis.

narration

read more

Alzheimer's biomarkers: Tau

In a healthy brain, tau proteins act as highways within brain cells, helping to transport necessary nutrients and other molecules. In the brains of people with Alzheimer’s, however, tau proteins begin to stick together, forming tangles that disrupt the normal function of neurons.

Tau detection is an important tool for monitoring Alzheimer's progression. As of now, blood tests that measure certain types of tau protein are generally more accurate than tests for beta-amyloid at tracking disease progression.

narration

read more

Biomarkers in blood and spinal fluid

Cerebrospinal fluid (CSF) is like a liquid fingerprint — and it can carry clues about health, including markers of Alzheimer's. The presence of protein biomarkers in CSF can flag abnormal brain activity, like inflammation or cell damage.

Neurologists might also look for these proteins in the blood. Blood tests for beta-amyloid and tau are relatively new and while they can't definitively diagnosis Alzheimer's on their own, they can add supporting evidence to the diagnostic process.

Blood biomarker tests

CSF biomarker tests

Blood is taken from a vein, usually in the arm, just like in routine bloodwork.

CSF is drawn via a lumbar puncture (spinal tap) to measure beta-amyloid or tau.

narration

What Alzheimer's blood tests look for

Neurology researcher Wagner Brum studies amyloid and tau in Alzheimer's.

Researcher's perspective

“We know that having high blood sugar is bad, and we know that having high cholesterol is bad, but with amyloid in the fluids, it’s the opposite. Having low [amounts] is bad because it means that it is accumulating into blocks in the brain.”

Wagner S. Brum Neurology researcher Federal University of Rio Grande do Sul

LEARN more

narration

Biomarkers in brain scans

Beta-amyloid and tau aren't only detectable in cerebrospinal fluid and blood: They can also appear in images via one of these types of brain scans. Brain imaging helps neurologists identify abnormal brain structures or changes during the diagnostic process, monitor disease progression over time, and evaluate the effectiveness of treatments.

Amyloid PET scans

Tau PET scans

FDG PET scans

narration

read more

Brain atrophy in Alzheimer's

As Alzheimer's progresses, neurons in the brain die off. This physical change can be tracked with various imaging tools, like PET scans, helping doctors understand disease progression and severity.

Healthy brain

Alzheimer's brain

narration

read more

Future biomarkers

Scientists are discovering and studying new types of biomarkers that could mean earlier and more accurate dementia diagnosis, well before symptoms appear. Early detection gives patients more opportunity for lifestyle modifications and treatments that could help delay the onset of symptoms.

Vocal signatures

Wearables data

Retinal biomarkers

narration

Why early detection matters

Dr. Peter Snyder is studying new retinal scan technology that may be able to identify markers of Alzheimer's disease, potentially allowing detection as early as 20 years before symptoms appear.

Expert perspective

“It's so much easier to protect [the brain] than to try to reverse time and go back. ... I believe that we're not going to be able to slow progression of the disease — we're not going to be able to develop a therapy that really is effective — unless we intervene earlier than... we've attempted so far."

Peter J. SnyderProfessor of Biomedical & Pharmaceutical SciencesUniversity of Rhode Island

watch the video

narration

Genetic biomarkers

Biomarkers are not the same for everyone; depending on a person's genes, their biomarker test results may need to be interpreted differently.

Learn more in the Being Patient Guide to Genetic Testing

Gene

Variant

Significance

Reduced risk

E2

APOE

Neutral risk

E3

(Alz. gene)

Higher risk

E4

narration

Want to learn more?

Visit

beingpatient.com

for the latest news and information on brain health and dementia

narration

Tau PET Scans

• detect tau tangles in the brain(still in research development)
• use radiotracers that bind specifically to tau deposits

Amyloid PET Scans

• detect beta-amyloid plaques in the brain
• use radiotracers that bind to amyloid proteins, allowing visualization of plaque deposits

FDG PET Scans

• assess glucose metabolism in the brain
• reduced glucose uptake in specific brain regions (e.g., the temporal and parietal lobes) is a biomarker for neuronal damage in Alzheimer’s and other dementias