Stuart Zola, Emory University, and partners
The Neurotrack test uses eye-tracking to detect Alzheimer's disease symptoms.

Photograph by Brandee Winstead

An older woman slouches in the glow of a computer screen, her head steadied on a chin rest. Two identical black-and-white images appear on the screen. The screen goes blank, and then two more images appear—one the same as earlier, the other new. The woman doesn’t say a word. She doesn’t move or point. The images change again and again. After about twenty-five minutes, her session is over.

The test appears passive, but its implications are profound. A healthy person looks more closely at new images than familiar ones. If an eye-tracking camera detects that someone gazes at both old and new images equally, that could be a sign of slight damage to the hippocampus, the seahorse-shaped memory center of the brain—and a very early indicator of Alzheimer’s disease. Tracking subtle differences in eye movement forms the basis of Neurotrack, a testing system that can determine with uncanny certainty who will develop Alzheimer’s disease in the next three to six years.

“We believe we have, for the first time, been able to push back the window of discovery and predictability,” says Stuart Zola, the Emory University neuroscientist whose research led to this device. “Early detection is the holy grail for any disease.”

Finding a cure for Alzheimer’s has become an urgent mission as the U.S. population ages. No disease is more feared except cancer, yet few people have given much thought to how they would cope with progressive mental decline.

At least 200,000 Georgia residents have Alzheimer’s (and related dementia disorders), but the total is likely larger because many people have not yet been diagnosed, says Leslie Anderson, president and CEO of the Georgia chapter of the Alzheimer’s Association. “It’s a crisis that’s upon us now.”

Zola, who also is director of the Yerkes National Primate Research Center at Emory, and his colleagues want to play a part in finding a cure. They tested Neurotrack on ninety-two people—some of them with mild cognitive impairment that might progress to Alzheimer’s, and others with no known memory problems. Every person with a score below fifty on the test eventually worsened, most reaching a diagnosis of Alzheimer’s within three years. Every person with a score of sixty-seven or above was clear of the disease three years later.

For the first time, researchers can pinpoint a set of people who will develop Alzheimer’s and others who won’t, without the costly or invasive tests previously available. That is valuable information for pharmaceutical companies, who can then explore medications.

Neurotrack set up headquarters in Palo Alto, California, and recently attracted a $2 million investment, including funds from Peter Thiel, a founder of PayPal. A web-based version of the test is in development, and Neurotrack may explore ways to use the test for conditions such as Parkinson’s. Eventually, it could become widely available in doctors’ offices.
“Once we have a medication,” says Elizabeth Buffalo, a colleague of Zola’s who is now at the University of Washington in Seattle, “the hope is that this would be something like a mammogram, an early screening tool that could reduce the number of individuals who are affected by this disease.”

This article originally appeared in our November 2013 issue.