University of Waterloo researchers behind new diagnostic test for Alzheimer's disease

Researchers at the University of Waterloo say they have discovered a "completely non-invasive" imaging technique for detecting Alzheimer's disease. 

• Imaging technique could shed new light on Alzheimer's disease

"We filter the light, send polarized light into the eye and then detect various polarizations coming back out of the eye," said Melanie Campbell, a professor at the University of Waterloo's department of physics and astronomy. "It's much less expensive [and] much more comfortable for the patient."

Campbell, who was attending the Alzheimer's Association International Conference in Toronto Wednesday, said researchers can peek through a window into the brain by seeing what was previously invisible in the retina using a technique that involves polarized film. 

Researchers are looking for amyloid deposits in the retina that are associated with neural cells, she said. 

"Those amyloid deposits are found in the brain, they make up the plaques in Alzheimer's disease and they are one of the diagnostics of the disease," she said. "We and others thought they might also occur in the retina and then we developed this non-invasive approach to actually image them in the retina."

Identifying amyloid deposits is important to researchers because "amyloid is known to occur before the symptoms of the disease," the professor noted.

"The ability to detect amyloid deposits in the retina prior to disease symptoms may be an essential tool for the development of preventative strategies for Alzheimer's and other dementias," she added.

Testing still needed

The test has been proven effective so far, Campbell said. 

"It's been very successful in the tissues that we've had after death from patients with Alzheimer's disease," she said. "We see it with high contrast in the vast majority of those people with the diagnosis of Alzheimer's disease."

Most other diagnostic options used to identify the disease look for amyloid in the brain, which can be much more costly and uncomfortable for the patient. 

The ability to detect amyloid deposits in the retina prior to disease symptoms may be an essential tool for the development of preventative strategies for Alzheimer's and other dementias.- Researcher Melanie Campbell

"We're talking about brain scans, which are relatively expensive," Campbell said. "They involve the use of a small amount of radiation and the use of injection dyes."

She acknowledged prototypes are being developed and clinical testing is set to take place over the next six months in Canada. It will likely be a matter of years before the test is used more generally for the screening of Alzheimer's. 

While there's no known cure for Alzheimer's, a progressive brain disorder that destroys memory and thinking cells, Campbell said early diagnosis is important so they can develop more effective treatments.

Campbell's research was done in association with colleagues at the University of Waterloo, the University of British Columbia, Vivocore Inc., InterVivo Solutions, the University of Rochester and Boston's Massachusetts General Hospital. 

Two studies highlighting the new diagnostic tool are expected to be revealed at the Toronto conference, which has been referred to by the University of Waterloo as the world's largest forum for Alzheimer's disease.