July 14, 2014
Research Opens Doors To Novel Alzheimer’s Diagnosis Methods
Brett Smith for redOrbit.com - Your Universe Online
The confirmation of an Alzheimer’s diagnosis typically involves one of two procedures – a spinal tap or a brain-imaging scan.
However, new research has opened the door to other possible methods – including a blood test, sense of smell exam or determining protein build-up in the eyes. Based in tests conducted on hundreds of patients, reports on the research are to be presented at the Alzheimer's Association International Conference in Denmark this week.
"In the face of the growing worldwide Alzheimer's disease epidemic, there is a pressing need for simple, less invasive diagnostic tests that will identify the risk of Alzheimer's much earlier in the disease process," said Heather Snyder, Alzheimer's Association director of Medical and Scientific Operations. "This is especially true as Alzheimer's researchers move treatment and prevention trials earlier in the course of the disease."
One study presented at the conference adds to the growing body of evidence that suggests individuals with an early form of Alzheimer’s have a decreased ability to properly identify odors. The study looked into connections involving olfaction, memory efficiency, loss of brain cell functionality, and amyloid deposition in more than 210 medically-normal seniors signed up for the Harvard Aging Brain Study with the Massachusetts General Hospital.
The scientists gave subjects the 40-item University of Pennsylvania Smell Identification Test (UPSIT) and a thorough battery of cognitive tests. They also assessed the size of two brain structures in the temporal lobes that are critical for memory: the entorhinal cortex and the hippocampus. The researchers also checked subjects for amyloid deposits in the brain, a phenomenon linked to Alzheimer’s.
They discovered that a smaller hippocampus and a thinner entorhinal cortex were connected with poorer smell identification and failing memory. The scientists also discovered that – in a subgroup of study volunteers with elevated levels of amyloid plaques – greater brain cell death was linked with worse olfactory function.
"Our research suggests that there may be a role for smell identification testing in clinically normal, older individuals who are at risk for Alzheimer's disease," said study researcher Matthew E. Growdon, a doctoral student at Harvard Medical School and Harvard School of Public Health. "For example, it may prove useful to identify proper candidates for more expensive or invasive tests. Our findings are promising but must be interpreted with caution. These results reflect a snapshot in time; research conducted over time will give us a better idea of the utility of olfactory testing for early detection of Alzheimer's."
Previous Alzheimer’s research has focused on beta amyloid plaques in the brain and another new study being presented this week looked to see if the amount of beta amyloid in people’s retinas could be linked with the cognitive disease.
In the study, volunteers took a proprietary dietary supplement containing curcumin, which adheres to beta-amyloid with high affinity and has luminescent properties that enable amyloid plaques to be found in the eyes using a unique system and a method called retinal amyloid imaging (RAI). Volunteers also went through brain amyloid PET imaging to associate amyloid deposition between the retina and brain.
Results of this preliminary trial indicate that amyloid levels discovered in the retina were notably correlated with brain amyloid levels found by imaging techniques. The retinal amyloid test also significantly differentiated between Alzheimer's and non-Alzheimer's participants, the study team said.
"We envision this technology potentially as an initial screen that could complement what is currently used: brain PET imaging, MRI imaging, and clinical tests," said study researcher Shaun Frost of the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Australia. "If further research shows that our initial findings are correct, it could potentially be delivered as part of an individual's regular eye check-up. The high resolution level of our images could also allow accurate monitoring of individual retinal plaques as a possible method to follow progression and response to therapy."
A similar study also looked at the connection between amyloid plaques in the lens of the eye and the level of plaques in the brain. Amyloid levels identified via an eye lens test correlated markedly with results achieved through PET brain imaging.
In another recent study, researchers at King's College London and UK proteomics company Proteome Sciences identified 10 proteins in the bloodstream can be used to recognize people with brain shrinkage that is a sign of moderate memory loss and Alzheimer's.
Ralph Nixon, chairman of the Alzheimer's Association's Medical & Scientific Advisory Council, told USA Today that people shouldn’t read too much into these studies just yet as not everyone with beta amyloid accumulation will develop Alzheimer's.
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