Understanding Alzheimer’s Disease

What is Alzheimer’s Disease?

Alzheimer’s disease is a neurological brain disorder that causes problems with memory, thinking skills, and behavior. It was named after a German physician, Aloïs Alzheimer, who first described it in 1906. Dr. Alzheimer was a pioneer in linking the symptoms of what we now call Alzheimer’s disease to the abnormal clumps (amyloid plaques) and tangled bundles of fibers (neurofibrillary tangles or tau) in the brain.

Alzheimer’s disease progresses over time, and because the life span of our population is growing longer, the number of people affected is increasing rapidly. Scientific researchers have made huge strides in understanding Alzheimer’s, offering that effective treatments, and possibly even a cure, are now within reach.

Memory loss is one of the earliest symptoms of Alzheimer’s, along with a gradual decline of other intellectual and thinking abilities (called cognitive functions), and changes in personality or behavior. Alzheimer’s is the most common form of dementia.

Browse this section to learn about the possible causes of Alzheimer’s disease, what happens to the brain as the disease progresses, and the risk factors and symptoms of Alzheimer’s.

Dementia vs. Alzheimer's

“What’s the difference between dementia and Alzheimer’s?” We hear that all the time here at the Fisher Center for Alzheimer’s Research Foundation. It’s a common question, and doctors can sometimes contribute to the confusion.

Alzheimer's Diagnosis

It’s important to seek a doctor’s diagnosis as soon as possible. There are many causes of dementia symptoms, and a diagnosis can determine how to treat them.

Top Ten Signs of Alzheimer's

Learn some of the first signs and symptoms of Alzheimer’s disease.

Clinical Trials

Is a clinical trial right for you or your loved one?


Scientific research is helping to inform and improve drug and non-drug approaches for the treatment of Alzheimer’s.

Clinical Stages of Alzheimer’s

New York University’s Dr. Barry Reisberg outlines the seven major clinical stages of Alzheimer’s disease. Dr. Reisberg is the Clinical Director of New York University’s Aging and Dementia Research Center.