The study, published in the journal Optics Letters, showed that as the microscopic plaques associated with Alzheimer's disease accumulate, the optical properties of the brain change and can be detected. Their technique could quantify differences between in-vitro samples and correctly identified signs of Alzheimer's in brain tissues taken from autopsies.

"We're primarily interested in finding a way of diagnosing and monitoring Alzheimer's disease during life," study leader Eugene Hanlon, a scientist with the U.S. Department of Veterans Affairs Research, said in a statement. "We think this technique has a lot of potential for detecting the disease early."

Hanlon and colleagues at Harvard Medical School/Beth Israel Deaconess Medical Center and Boston University suggest understanding how microscopic conditions of the brain cause light to scatter will allow analyzing of the brain with near-infrared light. The advantage would be infrared light would safely penetrate the skull and pass harmlessly through the brain.

Current imaging techniques, such as magnetic resonance imaging, are good at identifying the gross anatomical features associated with Alzheimer's but cannot detect early microscopic changes.