Alzheimer’s disease is a brain disorder that slowly destroys memory and thinking skills, and, eventually, the ability to carry out the simplest tasks. In most people with Alzheimer’s, symptoms first appear later in life. Estimates vary, but experts suggest that most of them age 65 or older, may have dementia caused by Alzheimer’s.

Alzheimer’s disease is currently ranked as the seventh leading cause of death and is the most common cause of dementia among older adults.

Dementia is the loss of cognitive functioning — thinking, remembering, and reasoning — and behavioural abilities to such an extent that it interferes with a person’s daily life and activities. Dementia ranges in severity from the mildest stage, when it is just beginning to affect a person’s functioning, to the most severe stage, when the person must depend completely on others for help with basic activities of daily living.

How does Alzheimer’s disease affect the brain?

Scientists continue to unravel the complex brain changes involved in Alzheimer’s disease. Changes in the brain may begin a decade or more before symptoms appear. During this very early stage of Alzheimer’s, toxic changes are taking place in the brain, including abnormal buildups of proteins that form amyloid plaques and tau tangles. Previously healthy neurons stop functioning, lose connections with other neurons, and die. Many other complex brain changes are thought to play a role in Alzheimer’s as well.