Alzheimer’s disease is a brain disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks. People with Alzheimer’s also experience changes in behavior and personality. In most people with Alzheimer’s, symptoms first appear later in life. Estimates vary, but experts suggest that more than 6 million Americans, most of them age 65 or older, may have dementia caused by Alzheimer’s.
Alzheimer’s disease is currently ranked as the sixth leading cause of death in the United States, but recent estimates indicate the disorder may rank third, just behind heart disease and cancer, as a cause of death for older people.
More than 6 million Americans, many of them age 65 and older, are estimated to have Alzheimer’s disease. That’s more individuals living with Alzheimer’s disease than the population of a large American city. Many more people experience Alzheimer’s in their lives as family members and friends of those with the disease.
The symptoms of Alzheimer’s disease — changes in thinking, remembering, reasoning, and behavior — are known as dementia. That’s why Alzheimer’s is sometimes referred to as “dementia.” Other diseases and conditions can also cause dementia, with Alzheimer’s being the most common cause of dementia in older adults.
Alzheimer’s disease is not a normal part of aging. It’s the result of complex changes in the brain that start years before symptoms appear and lead to the loss of brain cells and their connections.
Alzheimer’s is the most common cause of dementia among older adults. Dementia is the loss of cognitive functioning — thinking, remembering, and reasoning — and behavioral 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.
The causes of dementia can vary, depending on the types of brain changes that may be taking place. Other dementias include Lewy body dementia, frontotemporal disorders, and vascular dementia. It is common for people to have mixed dementia — a combination of two or more types of dementia. For example, some people have both Alzheimer’s disease and vascular dementia.