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Smell Test Shows Potential to Identify Alzheimer's Early
July 14, 2014

SMELL AND EYE TESTS SHOW POTENTIAL TO DETECT ALZHEIMER’S EARLY

New Alzheimer’s biomarker results reported at Alzheimer’s Association International Conference 2014 

COPENHAGEN, July 13, 2014 – A decreased ability to identify odors might indicate the development of cognitive impairment and Alzheimer’s disease, while examinations of the eye could indicate the build-up of beta-amyloid, a protein associated with Alzheimer’s, in the brain, according to the results of four research trials reported today at the Alzheimer’s Association International Conference® 2014 (AAIC® 2014) in Copenhagen.

 In two of the studies, the decreased ability to identify odors was significantly associated with loss of brain cell function and progression to Alzheimer’s disease. In two other studies, the level of beta-amyloid detected in the eye (a) was significantly correlated with the burden of beta-amyloid in the brain and (b) allowed researchers to accurately identify the people with Alzheimer’s in the studies.

Beta-amyloid protein is the primary material found in the sticky brain “plaques” characteristic of Alzheimer’s disease. It is known to build up in the brain many years before typical Alzheimer’s symptoms of memory loss and other cognitive problems.

“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, Ph.D., 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.”

“More research is needed in the very promising area of Alzheimer’s biomarkers because early detection is essential for early intervention and prevention, when new treatments become available. For now, these four studies reported at AAIC point to possible methods of early detection in a research setting to choose study populations for clinical trials of Alzheimer’s treatments and preventions,” Snyder said.

With the support of the Alzheimer’s Association and the Alzheimer’s community, the United States created its first National Plan to Address Alzheimer’s Disease in 2012. The plan includes the critical goal, which was adopted by the G8 at the Dementia Summit in 2013, of preventing and effectively treating Alzheimer’s by 2025. It is only through strong implementation and adequate funding of the plan, including an additional $200 million in fiscal year 2015 for Alzheimer's research, that we’ll meet that goal. For more information and to get involved, visit www.alz.org.

 

Clinically, at this time it is only possible to detect Alzheimer’s late in its development, when significant brain damage has already occurred. Biological markers of Alzheimer’s disease may be able to detect it at an earlier stage.  For example, using brain PET imaging in conjunction with a specialized chemical that binds to beta-amyloid protein, the buildup of the protein as plaques in the brain can be revealed years before symptoms appear. These scans can be expensive and are not available everywhere. Amyloid can also be detected in cerebrospinal fluid through a lumbar puncture where a needle is inserted between two bones (vertebrae) in your lower back to remove a sample of the fluid that surrounds your brain and spinal cord.
 
 
Odor Identification Deficits Linked with Transition from Mild Cognitive Impairment to Alzheimer’s
 
Davangere Devanand, M.B.B.S., M.D., Professor of Psychiatry (in Neurology and in the Sergievsky Center) at Columbia University Medical Center and colleagues investigated a multi-ethnic (34% White, 30% African-American, 36% Hispanic) sample of 1037 non-demented elderly people in New York City, with an average age of 80.7, and assessed them in a variety of ways at three time periods – from 2004-2006, 2006-2008, and 2008-2010. UPSIT was administered in English and Spanish between 2004 and 2006. During follow-up 109 people transitioned to dementia (101=Alzheimer’s); there were 270 deaths.



At AAIC 2014, Devanand reported that, in 757 subjects who were followed, lower odor identification scores on UPSIT were significantly associated with the transition to dementia and Alzheimer’s disease, after controlling for demographic, cognitive, and functional measures, language of administration, and apolipoprotein E genotype.  For each point lower that a person scored on the UPSIT, the risk of Alzheimer’s increased by about 10%.  Further, lower baseline UPSIT scores, but not measures of verbal memory, were significantly associated with cognitive decline in participants without baseline cognitive impairment.

 
“Odor identification deficits were associated with the transition to dementia and Alzheimer’s disease, and with cognitive decline in cognitively intact participants, in our community sample. The test was effective in both English and Spanish,” said Devanand. “If further large-scale studies reproduce these results, a relatively inexpensive test such as odor identification may be able to identify subjects at increased risk of dementia and Alzheimer’s disease at a very early stage, and may be useful in identifying people at increased risk of cognitive decline more broadly.”

 

 

 

 

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