Alzheimer’s Disease (AD)
July 20, 2026
Online Clinic
Brain & Nervous System
About 6.7 million persons older than 65 in the U.S. have Alzheimer’s disease (AD). It is the most common cause of dementia – a broad term that means cognitive function declines enough to interfere with daily life activities.
Alzheimer’s disease has a gradual onset. How quickly signs and symptoms occur and progress varies from person to person.
Signs & Symptoms
- Memory changes that disrupt daily life. Persons with AD forget important dates, events, and/or information. They may also ask the same question over and over.
- Problems doing familiar tasks. Persons with AD may have a hard time fixing a meal or driving to a familiar place.
- New problems speaking or writing. Often forget simple words or phrases or use unusual words for things.
- Problems with visual images and spatial relationships. May have problems with reading, color and contrast, and judging distance.
- Problems with planning and/or solving problems. Persons with AD have trouble making and following plans. They have trouble working with numbers, such as balancing a checkbook.
- Problems with awareness of time and place. May forget where they are, how they got there, and how to get back home. They may lose track of dates and seasons.
- Poor or decreased judgment. Neglect daily grooming and may not dress right for the weather. They show poor judgment about money.
- Misplacing things and can not retrace their steps to find them. They put things in unusual places, such as a wristwatch in a sugar bowl.
- Changes in mood or personality. Can get very confused, depressed, fearful, and worried. They rely on someone else to make decisions for them.
- Withdrawal from social activities and work. Get less involved with hobbies, social events, sports, and work.
Causes
With AD, certain protein deposits (plaques) and twisted fibers (tangles) build up in the brain. Over time, this causes large numbers of nerve cells in the brain to die.
Risk factors for AD are getting older and a family history of the disease. Having heart disease, diabetes, high blood pressure, a stroke, or a brain injury may increase the risk. Staying physically and mentally active and eating healthy throughout life may lower the risk for AD.