Alzheimer's disease eye scan

Credit: Cedars-Sinai

A non-invasive cost-effective simple eye test appears to be coming soon that can identify Alzheimer’s disease many years before symptoms arise.   It has only been in recent years, that there was any test for people with this devastating form of dementia. Doctors today can use expensive positron emission tomography (PET) scans of the brains to identify amyloid markers of the disease.  The PET test is invasive in that patients need to be injected with radioactive dye and is a part of the estimated $259 billion in healthcare costs attributed to Alzheimer’s disease treatment.

Doctors are not absolutely sure what triggers Alzheimer’s but plaques and tangles (twisted fibers) are the end result in cell death in the brain of those stricken with this disease. These plaques are atypical clusters of chemically “sticky” proteins called beta-amyloid that build up between nerve cells (neurons) in the brain. In a study of 16 patients at Cedars-Sinai Hospital in Los Angeles with Alzheimer’s found they had more than twice as much beta-amyloid in their retinas.  Neurosurgeon Professor Maya Koronyo-Hamaoui, of Cedars-Sinai Medical Center, Los Angeles, said: “Analysis of retinal amyloid index (RAI) scores showed a 2.1-fold increase in Alzheimer’s disease patients.”

In early human development in the womb, the retina of the eye is formed from the same tissue as the brain.  Even before this study there has been a suspicion that there is a link between the ratio of beta-amyloid protein in the eye and amyloid in the brain.  There is even a disease reference to ‘dementia of the eye’ and age-related macular degeneration (AMD) is linked to a buildup of beta-amyloid proteins in the retina.  The Cedars-Sinai team in an article entitled “Retinal Amyloid Pathology and Proof-of-Concept Imaging Trial in Alzheimer’s Disease” published recently in JCI Insight, say they believe beta-amyloid begins to accumulate in the eyes maybe 20 years or more before symptoms develop in the brain.

The non-invasive technique developed by the Cedars-Sinai team with investigators at NeuroVision Imaging, Commonwealth Scientific and Industrial Research Organisation, University of Southern California, and UCLA
have their patients drink a solution containing the natural fluorescent yellow extract curcumin, the main chemical in the curry spice turmeric. Besides curcumin’s natural fluorescent glow, in a micronized form it can cross the blood-brain and blood-retina barrier then binds to the sticky amyloid plaques.  The curcumin solution highlights the amyloid deposits at the back of the eye using a portable extremity imaging device. We recently reviewed on the best forms of curcumin supplements here.

Co-senior study investigator Keith Black, M.D., chair of Cedars-Sinai’s department of neurosurgery and director of the Maxine Dunitz Neurosurgical Institute stated: “Our hope is that eventually the investigational eye scan will be used as a screening device to detect the disease early enough to intervene and change the course of the disorder with medications and lifestyle changes.”