A new study in the Annals of Neurology suggests that a spinal tap can detect a biomarker signal­ing Alzheimer's before any symptoms appear. Today Alzheimer's is only posi­tively confirmed after death.

The study was conducted by the University of Pennsylvania School of Medicine. Researchers tested the spinal fluid of 300 people who were in their 70s: 114 had normal memories, 200 had memory problems, and 102 had Alzheimer's disease.

The testing was found to be very accurate in predicting Alzheimer's in individuals with failing memories.

The test would not change the outcome, but it would lead to earlier treatments that may delay the onset. Spinal taps can be an uncomfortable procedure, so this method likely will not be used as a routine screening test.

Alzheimer's may begin as much as a decade before symptoms. Although ge­netics plays a role, Alzheimer's is closely related to vascular decline. Proactive steps focus on maintaining healthy blood vessels with a good diet, performing physical activity, and avoiding smoking.

Researchers also are working on new positron emission tomography scans of the brain to detect the presence of amyloid plaques.

According to the National Institute on Aging, 2.4 to 5.1 million Americans may have Alzheimer's.