Are there biomarkers for Alzheimers disease?

Summary

Scientists are actively studying the brains of people with Alzheimer's disease in the hope of being able to diagnose it earlier, or confirm a diagnosis in someone with symptoms. One test that appears promising is analysis of spinal fluid for protein fragments. Alzheimer's disease produces many changes to the brain. Among these are the presence of large amounts of what are called plaques and tangles. Plaques are formed of protein fragments called amyloid beta. The fragments accumulate and form hard plaques between nerve cells, or neurons. Tangles are twisted fragments of a protein called tau found inside neurons. In Alzheimer's disease, neurons in certain parts of the brain become damaged and die. When the nerve cells die, fragments from the plaques and tangles enter the cerebrospinal fluid, which bathes the entire brain. The cerebrospinal fluid flows down into the spinal column. Samples of this fluid can be taken through a procedure called a spinal tap. It can then be analyzed for the presence of these proteins. Another test involving brain scans and a dye to image plaque in the brain was recently approved by the FDA. Not everyone who has these fragments, or everyone who has plaques and tangles, will develop Alzheimer's disease. But these are important steps towards understanding more about this devastating disease.