In the Alzheimer's Series:

• An Introduction to Alzheimer's
• Symptoms of Alzheimer's
• Causes of Alzheimer's
• Treatment of Alzheimer's
• How Alzheimer's is Diagnosed
• What is the Outlook for Alzheimer's?
• Further Information

Today, the only definite way to diagnose Alzheimer's disease is to find out whether there are plaques and tangles in brain tissue. To look at brain tissue, doctors must wait until they do an autopsy, which is an examination of the body done after a person dies. Therefore, doctors must make a diagnosis of "possible" or "probable" Alzheimer's disease.

At specialized centers, doctors can diagnose Alzheimer's disease correctly up to 90 percent of the time. Doctors use several tools to diagnose "probable" Alzheimer's disease:

• A complete medical history includes information about the person's general health, past medical problems, and any difficulties the person has carrying out daily activities.
• Medical tests - such as tests of blood, urine, or spinal fluid - help the doctor find other possible diseases causing the symptoms.
• Neuropsychological tests measure memory, problem solving, attention, counting, and language.
• Brain scans allow the doctor to look at a picture of the brain to see if anything does not look normal.

Information from the medical history and test results help the doctor rule out other possible causes of the person's symptoms. For example, thyroid problems, drug reactions, depression, brain tumors, and blood vessel disease in the brain can cause Alzheimer's disease-like symptoms. Some of these other conditions can be treated successfully.

What is the outlook for someone diagnosed with Alzheimer's disease?

The course the disease takes and how fast changes occur vary from person to person. On average, Alzheimer's disease patients live from 8 to 10 years after they are diagnosed, though the disease can last for as many as 20 years.

Why is early diagnosis important?

An early, accurate diagnosis of Alzheimer's disease helps patients and their families plan for the future. It gives them time to discuss care options while the patient can still take part in making decisions. Early diagnosis also offers the best chance to treat the symptoms of the disease.

Last reviewed: By John M. Grohol, Psy.D. on 12 Oct 2006