“Alzheimer’s disease is a type of brain disease, just as coronary artery disease is a type of heart disease. It is
caused by damage to nerve cells (neurons) in the brain. The brain’s neurons are essential to thinking, walking,
talking and all human activity.  In Alzheimer’s, the neurons damaged first are those in parts of the brain responsible for memory, language and thinking. As a result, the first symptoms tend to be memory,
language and thinking problems. Although these symptoms are new to the individual affected, the brain changes that cause them are thought to begin 20 years or more before symptoms start.”.

Alzheimer’s Association (https://www.alz.org › alzheimers-facts-and-figures)