From: olivercranglejr@gmail.com   
      
   Could eye and smell tests offer early Alzheimer's diagnosis?    
      
   Tue 15 Jul 2014 - 8am PST    
   Alzheimer's / DementiaNeurology / NeuroscienceEye Health / BlindnessMedical   
   Devices / Diagnosticsadd your opinionemail    
      
   In the US, someone is diagnosed with Alzheimer's disease every 67 seconds.   
   Current clinical diagnostic tests mean the disease can only be detected in its   
   late stages. But four new studies recently presented at the Alzheimer's   
   Association International    
   Conference 2014 in Copenhagen, Denmark, suggest that eye and smell tests could   
   be used for early detection of Alzheimer's.    
   Alzheimer's disease is the most common form of dementia, characterized by   
   problems with memory, thinking and behavior.    
      
   Although the exact cause of Alzheimer's is unclear, scientists suspect that   
   the formation of beta-amyloid plaques - abnormal clusters of protein fragments   
   that accumulate between nerve cells - may play a part by triggering brain cell   
   death, causing    
   cognitive impairment.    
      
   Past research has suggested that in the early stages of Alzheimer's, sense of   
   smell begins to diminish. Two new studies investigated the association further   
   to determine whether sense of smell could be used to detect early stages of   
   Alzheimer's.    
      
   The first study was led by Dr. Matthew E. Growdon of Harvard Medical School   
   and Harvard School of Public Health in Boston, MA. Dr. Growdon and colleagues   
   analyzed 215 healthy individuals who were a part of the Harvard Aging Brain   
   Study at Massachusetts    
   General Hospital.    
      
   Participants underwent a series of cognitive tests as well as the 40-item   
   University of Pennsylvania Smell Identification Test (UPSIT), which measured   
   their olfactory function - their sense of smell. In addition, the team   
   measured the size of two brain    
   structures among participants that are located in the temporal lobes - the   
   entorhinal cortex and the hippocampus (a region associated with memory) - and   
   the levels of amyloid proteins in their brains.    
      
   Odor identification tests 'could be useful for early detection of Alzheimer's'    
   According to the researchers, they found that participants who had a thinner   
   entorhinal cortex and a smaller hippocampus had worse memory and smell   
   identification than those with a larger hippocampus and a thicker entorhinal   
   cortex.    
      
   woman smelling flowers    
   The results of two new studies suggest that a smell test could be used for   
   early detection of Alzheimer's.    
   In addition, the team reports that participants who had high levels of amyloid   
   proteins and a thinner entorhinal cortex - which they linked to greater brain   
   cell death - had worse olfactory function.    
      
   Although Dr. Growdon says the team's findings should be "interpreted with   
   caution," he believes the 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."    
      
   Another study, led by Dr. Davangere Devanand of the Columbia University   
   Medical Center in New York, NY, supports this theory. The research team   
   conducted an analysis of 1,037 elderly individuals without dementia. They   
   followed the participants over three    
   time periods: 2004-06, 2006-08 and 2008-10.    
      
   They found that among 757 subjects, lower UPSIT scores were associated with   
   development of dementia and Alzheimer's disease. The risk of Alzheimer's   
   increased by 10% for each lower point scored on UPSIT. Furthermore, they found   
   that lower baseline UPSIT    
   scores were linked to cognitive decline in participants who did not have   
   cognitive impairment at study baseline.    
      
   Commenting on the findings, Dr. Devanand says:    
      
   "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."    
      
   Eye imaging techniques show promise for early Alzheimer's diagnosis    
   But it is not only olfactory tests that may be useful for the early detection   
   of Alzheimer's, according to a further two studies presented at the   
   conference.    
      
   Past research has indicated that among individuals with Alzheimer's,   
   beta-amyloid plaques similar to those found in the brain can be found in the   
   retinas - a sensory tissue that lines the inner surface of the eyes.    
      
   Fast facts about Alzheimer's disease    
   More than 5 million people in the US are living with Alzheimer's disease    
   The disease is the 6th leading cause of death in the US    
   Around two thirds of Americans with Alzheimer's are women    
   By 2050, the number of people with Alzheimer's is expected to triple to as   
   many as 16 million.    
   In the first study - which provides preliminary results for 40 out of 200   
   participants - Shaun Frost, of the Commonwealth Scientific and Industrial   
   Research Organization (CSIRO) in Australia, and colleagues suggest that levels   
   of amyloid proteins in the    
   retina could be used to determine levels of amyloid proteins in the brain,   
   therefore providing a potential method for early Alzheimer's detection.    
      
   To reach their findings, the team gave participants a supplement containing   
   curcumin - a compound that binds to amyloid proteins and illuminates them.   
   This allowed the researchers to detect amyloid plaques in the eye using a   
   method called retinal amyloid    
   imaging (RAI). Participants then underwent PET (position emission tomography)   
   imaging so the researchers could correlate amyloid levels in the eye with that   
   in the brain.    
      
   From this, they have found that so far, amyloid levels detected in the eye   
   correspond with amyloid levels in the brain. In addition, the RAI test has   
   been able to differentiate between subjects with and without Alzheimer's with   
   80.6% specificity and 100%    
   sensitivity.    
      
   Based on their findings to date, Frost and colleagues believe that retinal   
   tests could be used to detect the early stages of Alzheimer's disease.    
      
   "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,"   
   says Frost. "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."    
      
   In another study, Paul. D. Hartung, president and CEO of Cognoptix Inc. in   
   Massachusetts, and colleagues analyzed 20 individuals with potential   
   Alzheimer's alongside 20 healthy people.    
      
      
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