CTE causes a protein known as tau to form around the brain’s blood vessels, interrupting normal functions and eventually killing nerve cells. At this early stage, no symptoms will be present. As the disease progresses, more defective tau affects the nerve cells in the frontal lobes of the brain, then this expands to the temporal section and begins to impair emotion and memory. Lastly, the brain is overwhelmed by these deposits and many of the nerve cells are killed. The brain now has shrunk to half of its size and mental processes are severely affected. Repeated blows to the head are the main cause of CTE.
