Research Brings Us One Step Closer to Better Treatment By Michael Smith , MD
WebMD Medical News
Jan. 22, 2002 -- Finding an early, accurate test for Alzheimer's disease would be one of the greatest medical discoveries in recent history. And with the flurry of research in this area, it may be closer than we think.
Currently, it's impossible to say with 100% accuracy if someone has Alzheimer's disease without doing a brain biopsy after death. But since this doesn't offer much help when it comes to treating live patients, doctors do a lot of tests and then make an educated guess as to whether a person has Alzheimer's.
But a new study shows that a blood test can accurately predict Alzheimer's disease in people with very few symptoms. The study appears in the January issue of Archives of Neurology.
Several recent studies have looked at new tests to diagnose Alzheimer's in people with early signs of memory loss. WebMD has reported on these studies, including several looking at the use of a brain scan, called "positron emission tomography," or PET. This scan is showing great promise in analyzing brain metabolism and predicting which people with memory problems are likely to develop full-blown Alzheimer's.
In the current study, researchers at the University of Brescia in Italy looked at 86 people with either mild dementia or memory problems that weren't yet significant enough to call dementia. People with Alzheimer's are known to have a buildup of a substance called amyloid precursor protein, in their brains. But levels of this protein in people with Alzheimer's are also abnormally low in the blood-clotting cells called platelets.
This gave lead author Alessandro Padovani, MD, PhD, and colleagues easy access to a potential early test for Alzheimer's disease.
The level of amyloid precursor protein in platelets was significantly lower in the people with early mild Alzheimer's than in those without memory problems. People with memory problems -- called "mild cognitive impairment" by your doctor -- had much lower levels of the protein, as well.
With further evaluation, the test was seen to be close to 90% accurate in identifying people with either mild Alzheimer's or mild cognitive impairment.
Although you can't rush to your doctor to have this blood test, it holds great potential for an easy, accurate test for Alzheimer's.
Ideally, a useful test for Alzheimer's would be able to diagnose the disease before symptoms develop. Thus, such a test would be most useful in someone at high risk for Alzheimer's -- someone with a strong family history or with an abnormal ApoE gene, known to be linked to Alzheimer's.
And even more important, such a test would allow doctors to treat the disease earlier, and better delay severe problems down the road. And finding a cure for a disease often starts with identifying early signs of trouble.