Alzheimer’s Disease: Overview, Causes, and Symptoms (AD)

Alzheimer's disease (AD) is among the most feared of all illnesses. Perhaps because we find it so terrifying—or embarrassing, or simply too depressing—Alzheimer's is not often discussed among friends and families.

But our tendency to avoid talking about unpleasant subjects (like AD) may leave us wishing we understood them better, that we had more information at hand. This page will provide you with some of that information, from an overview of dementia and the difference between AD and memory loss to the disease's causes, and symptoms. The next section provides information about treatments.

Overview of Dementia and Alzheimer's Disease
Dementia is a medical condition that upsets the way the brain works. Generally used to describe people with deteriorated mental functioning, dementia can affect young and old alike. It is not a normal part of the aging process.

There are many different types of dementia, and many different causes. Alzheimer's disease (AD) is the most common form of dementia. Because people tend to develop AD as they age, the number of people it strikes is growing as more people are living longer.

Difference Between AD and Memory Loss
Brain researchers are working hard to pin down where forgetfulness ends and Alzheimer's begins.

Age related memory impairment
Memory loss is one of the earliest symptoms of Alzheimer's and other dementias. But clear differences exist between dementia and what scientists call "age-related memory loss" (ARML). These differences can be seen in the symptoms that people experience, as well as in actual changes in the brain.

While dementia involves an overall loss of cognitive (mental) abilities, ARML is primarily a decrease in the ability to recall facts, people, places, and things that we encounter daily. For example: We all forget, occasionally, where we parked our cars; but forgetting what your car looks like may be a cause for concern.

One important clue from brain research is that people with Alzheimer's retain much less information than healthy people after a delay. This means they can learn new information, but will remember little after a delay of even a few hours.

Memory changes and AD
In some, but not all patients—mild cognitive impairment (MCI), a condition marked by repeated lapses in short-term memory—may be early-stage Alzheimer's. Changes in memory that occur over a year or two, and which can be measured through psychological testing, are the trademarks of MCI.

Such changes may be very mild at first, and are often first noticed by a loved one. If you, or someone you love, are experiencing changes in memory or forgetfulness that interfere with work or home responsibilities, seek a doctor's help.

Stress and fatigue can also affect memory, but even if MCI is diagnosed, there may be a cause other than early Alzheimer's (such as side effects from medications, depression, stroke, or a head injury).

Causes of AD
Alzheimer's is a neurodegenerative disease, which means neurons (brain cells) deteriorate over time. Eventually, these nerve cells stop functioning and die. Cells in the hippocampus—a seahorse-shaped structure deep in the brain that plays a major role in the formation of memories—appear to be especially vulnerable.

Many experts believe that cell death is related to the buildup of a sticky protein called amyloid, which forms the dense plaques (or areas of build-up) and tangles of nerve fibers that a physician named Alois Alzheimer described more than 100 years ago.

Whether these amyloid plaques are the cause of cell death—or just the remnants of it—is not perfectly clear. Researchers are also studying other proteins; they may find that the interaction of different proteins ultimately leads to cell death.

To date, scientists have been unable to figure out what triggers Alzheimer's disease in some people and not in others. Inherited genes play a role in the rare early-onset forms of Alzheimer's, but their influence on the more common form is less clear.

Symptoms of Alzheimer's Disease
In addition to memory loss, the first signs of Alzheimer's often include language difficulties and trouble with routine activities, such as driving and shopping. In late-stage Alzheimer's, the abilities to talk and walk are likely to be lost

Each person with Alzheimer's may experience different symptoms, which can change over the course of the disease. Some of the most common symptoms are described below:

• Profound difficulty in recalling names, objects, places, times, and dates
• Not recognizing family and friends, or not recalling their names
• Forgetting one's own phone number or address
• Difficulty finding your way to or from a familiar place
• Tendency to wander from home or office
• Forgetting to eat or maintain one's hygiene
• Day/night disorientation with difficulty sleeping
• Noticeable language and intellectual decline
• Poor judgment, inability to follow simple instructions or stay focused on a task
• Progressive sense of distrust
• Dulled emotions or interest in activities
• Depression
• Unusual agitation and irritability
• Hallucinations or delusions
  

Source: Alzheimer's Association

On the next page, you will learn more about the symptoms of AD, how the disease is diagnosed and treated, and what you can do to make living with AD easier for yourself or a loved one.