Health Watch -- Diagnosing Alzheimer's Disease

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How can doctors tell the difference between Alzheimer's disease and other forms of dementia?

Alzheimer's disease isn't the only condition that causes memory loss and dementia. But even though the disease affects millions and was identified nearly a century ago, there hasn't been a definitive method for diagnosing Alzheimer's disease in a living patient. It took an autopsy to confirm the diagnosis.

Now researchers at UT Southwestern Medical Center at Dallas have found a method of confirming Alzheimer's disease that's nearly 100 percent accurate when combined with clinical assessment. The method uses a single-photon emission computed tomography - or SPECT - scan to test blood flow in a certain part of the brain. It's a test that provides a three-dimensional picture of blood flow in the brain.

In patients with Alzheimer's disease, blood flow is reduced in a structure called the posterior cingulate cortex. This part of the brain helps process information from parts of the brain that store vocabulary and geographical information.

Dr. Frederick Bonte, director of UT Southwestern's Nuclear Medicine Center, says this pattern of blood flow can show the difference between Alzheimer's disease and frontotemporal disease, which is another cause of dementia. Now that there are some treatments for Alzheimer's disease and there's a possibility of a cure in the not-too-distant future, it's more important to be able to make a definitive diagnosis of Alzheimer's disease in the earliest possible stages.


May 2004