Laser Could Detect Alzheimer's Early

July 08, 2008 -- The only definitive diagnosis of Alzheimer's disease is a brain slice from a cadaver -- which is obviously not much help for the living.

But now a new laser that harmlessly penetrates deep into the live brain could help diagnose Alzheimer's before its most tragic effects are apparent.

The laser won't treat the disease -- no cure for Alzheimer's exists -- but it could give scientists a better understanding of the disease, which could then lead to better treatments.

"The ability to detect [Alzheimer's-linked brain plaques] early would be a great boon," said Eugene Hanlon, a doctor at the Veterans Affairs Medical Center in Mass. and co-author on the study that appears in Optics Express. "Doing therapy early on is when it would be most effective."

There have been other physical diagnostics for Alzheimer's, such as lasers, MRI, and PET scans, but none of them have had the power to penetrate skin, bone and brain to find the protein groups that scientists think gum up neurons.

The new system involves shining a near-infrared laser into the brain. When the light hits the protein clumps linked with Alzheimer's, the light scatters in a "distinctive" pattern that is the picked up by detectors, said Hanlon. 

Hanlon and his colleagues have tested the laser on brain tissue and hope to have a clinical trial involving live patients within a couple years.

Currently Alzheimer's disease is diagnosed with about 85 percent accuracy, according to Hanlon, by asking questions, such as if the patient remembers their name or where they are. If the patient can't answer, or answers incorrectly, doctors can be reasonably certain that the patient has the disease.