The pathology of Alzheimer's

Alzheimer's disease is one of those potentially inevitable, maybe preventable, what the heck is really causing it diseases that came on to the medical scene in the 20th century. Essentially, as a person ages the brain atrophies slightly, and in some people they experience age-related memory problems and other cognitive effects of making it through a longer life than previous generations of humans. In other people, pathological changes to the brain induce a more pronounced memory issue that then manifests as dementia - this is Alzheimer's disease.

The disorder is diagnosed based on symptoms because the changes to the brain can't be confirmed until autopsy, showing the protein plaques in the brain tissue and spongy consistency that causes the cognitive changes. Aberrant protein beta-amyloid has long been blamed as the source of the plaques, causing Alzheimer's to be related to prion diseases and spongiform encephalopathies like mad cow, but inappropriate aggregations of naturally occurring tau protein might also be to blame, making the disease more complex and multifactorial.

Read about tau and how it relates to nerve degeneration.

From the National Institute on Aging