Alzheimer's Overview

Diagnosing Alzheimer's Disease

Amyloid plaques
Amyloid plaques
3D Clinic/Getty Images

The main problem with diagnosing Alzheimer's disease is that it can only be done with certainty by examining brain tissue after the patient has died. A doctor can look for plaques, tangles and overall shrinkage in the brain of the deceased. With the living, doctors do the best they can, often making patients undergo a series of tests. These tests can yield a 90 percent success rate in correctly diagnosing the disease [source: Mayo Clinic]. The doctor might test various bodily fluids, such as blood, urine or spinal fluid. (A blood test can be used to see if the patient is genetically predisposed to develop Alzheimer's, though it can't produce an actual diagnosis.)

­­A brain scan -- MRI, PET or CT scan -- is another useful tool, allowing the doctor to look for unusual formations in the brain. The doctor will also conduct an interview in which he or she asks the patient about memory, any health problems (past and present), difficulties performing routine tasks, any trouble remembering faces and names, and other possible symptoms. He or she will also conduct exercises that test attention span, counting abilities and short-term versus long-term memory. If the patient has a caregiver or close family members, the doctor may also interview them. Above all, it's important that a doctor eliminates other potential causes of the patient's problems; other forms of dementia, minor strokes and mild cognitive impairment could all produce some of the symptoms of Alzheimer's disease.

­In recent research into Alzheimer's diagnosis, use of brain scanning and brain imaging is particularly popular. The results of a study released in August 2008 show that PET scans may yield important insights into detecting plaques, believed to be one of the main culprits in the disruption of brain function in Alzheimer's patients [source: NIH/Reuters]. Early diagnosis allows doctors to decide whether a patient may benefit from one of the drugs proven to temporarily stave off the disease's symptoms.

Some people choose to have genetic testing in order to determine whether they have the genes associated with early-onset Alzheimer's or if they have the Alzheimer's-associated form of the ApoE gene. However, some people carry ApoE and never develop Alzheimer's disease. Still, genetic testing can help a person learn more about his or her susceptibility to Alzheimer's, particularly the early-onset variety, and offers an opportunity to discuss with a doctor how to monitor possible symptoms.

On the next page, we'll take a look at how doctors treat Alzheimer's disease.