Amyloid plaques

What causes Alzheimer's Disease?

There are a number of theories as to what causes changes in how the brain works and which of these changes leads to or causes Alzheimer's disease. Scientists do know that it is breakdown in a part of the brain's processes interferes with its ability to function effectively.  

Two abnormal structures that are accepted as indicators of Alzheimer's disease are:

  • Amyloid plaques- dense protein deposits that form outside and around nerve cells in the brain. Whether they are a cause or a by-product of Alzheimer's disease is not yet known. Are thought to cause damage to nearby nerve cells.
  • Neurofibrillary tangles - inside the affected nerve cells are twisted strands of fibrils called tangles. These tangles appear to destroy the cells internal structure. 

As cells are damaged by Alzheimer's disease, the functions controlled by the affected parts of the brain, such as memory, language, problem solving skills, become impaired or lost all together. The nerve cells stop working, lose their ability to communicate with other nerve cells and the die. As the nerve cells die, the brain shrinks is size and weight.

Over time this disease affects different areas of the brain. Alzheimer's affects each person individually because of the person's personality, personal history and life experiences. As the disease unfolds however, it follows a specific pattern for most people.

Learn more about Alzheimer's and how it affects the brain.