What is Alzheimer’s disease?
Alzheimer’s disease is the most common cause of dementia in older adults. It affects more than five million Americans, and thousands more live with related disorders, like Lewy body, frontotemporal and vascular dementias.
Alzheimer’s disease is an irreversible, progressive brain disease that slowly destroys memory and thinking skills and, eventually even the ability to carry out the simplest tasks of daily living. In most people with Alzheimer’s, symptoms first appear after age 60. Alzheimer’s disease is the most common cause of dementia among older people.
The disease is named after Dr. Alois Alzheimer. In 1906, Dr. Alzheimer noticed changes in the brain tissue of a woman who had died of an unusual mental illness. Her symptoms included memory loss, language problems, and unpredictable behavior. After she died, he examined her brain and found many abnormal clumps (now called amyloid plaques) and tangled bundles of fibers (now called neurofibrillary tangles).
Plaques and tangles in the brain are two of the main features of Alzheimer’s disease. The third is the loss of connections between nerve cells (neurons) in the brain.
Although treatment can slow the progression of Alzheimer’s and help manage symptoms in some people, currently there is no cure for this devastating disease.
How many Americans have Alzheimer’s disease?
Estimates vary, but experts suggest that as many as 6 million Americans have Alzheimer’s disease. Unless the disease can be effectively treated or prevented, the number of people with it will increase significantly if current population trends continue. That’s because the risk of Alzheimer’s increases with age and the U.S. population is aging. The number of people with Alzheimer’s doubles for every 5-year interval beyond age 65.
What is dementia?
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 basic activities of daily living.