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.
Recently, scientists have focused on a type of memory change called mild cognitive impairment, or MCI. MCI is different from both Alzheimer's disease and normal age-related memory change. People with MCI have ongoing memory problems but do not have other losses like confusion, attention problems, and difficulty with language.
Scientists funded by the National Institute on Aging are conducting the Memory Impairment Study to learn whether early diagnosis and treatment of MCI might prevent or slow further memory loss, including the development of Alzheimer's.
