A biomarker is some kind of medical information from a person that can be measured. Commonly used biomarkers include cholesterol levels, blood pressure, and heart rate. These are measurements from a person that provide some kind of information about their body or their health. A biomarker is different from a symptom, which can be described and observed but not necessarily measured.
There are efforts to learn more about biomarkers that are associated with Alzheimer’s disease and related dementias in order to give the medical community more tools to use for prevention, detection, and diagnosis of these diseases. Much of the diagnostic process now relies on observation of symptoms, like memory loss, loss of judgement, and changes in personality. The addition of biomarker measurements adds strength to the diagnosis and could even help us detect a disease before symptoms are present.
The biomarkers that we currently know of to detect the presence and progression of Alzheimer’s and other diseases measure the size and function of the brain and levels of certain proteins associated with these diseases in the brain. Biomarkers are especially useful when measured over time, to keep track of changes in the brain. Biomarkers currently used include things like the size of certain brain regions and whether they are growing or shrinking, the health and size of blood vessels, the presence of tumors, bleeding, the presence and absorption of glucose, and the amount of beta-amyloid and tau proteins.
How do scientists and medical professionals get these measurements? A number of tools may be used, depending on which biomarkers they are looking for in each situation. Images may be taken of the brain using a CT scan, MRI, or PET scan to look for damage, shrinkage, blood flow, and glucose absorption. Cerebrospinal fluid may be taken from the brain or spinal cord to measure protein levels. Blood tests may also be used to measure proteins and other substances.
Biomarkers are still being studied and discovered to help detect and diagnose dementia related diseases. This is an important area of study for the research community, and something we hope to continue learning more about in the future.
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