NEWS - Simple smelling test detects Alzheimer's risk

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Simple smelling test detects Alzheimer's risk

Last Updated: 2004-12-13 14:54:43 -0400 (Reuters Health)

By Alison McCook

NEW YORK (Reuters Health) - People who have mild memory problems but who

can correctly identify the source of certain smells are probably not in

the first stages of Alzheimer's disease, suggesting that smell tests

could offer a new technique for early diagnosis, researchers reported

Monday.

As part of the test, people with cognitive difficulties completed a

" scratch and sniff " test, in which they scratched off 40 different odors

and used multiple choice to identify the origin of each smell.

Study author Dr. D.P. Devanand of Columbia University in New York

explained that all of the people in the study had visited a memory

clinic because they were having problems, but none of the traditional

evaluations could determine clearly whether they were in the early

stages of Alzheimer's disease.

People who never developed Alzheimer's disease tended to correctly

identify around 35 scents, while people who eventually were diagnosed

with the brain disorder could pinpoint only about 20 to 30 scents

correctly, Devanand explained.

Looking at individual scents, the researchers found that people's

ability to identify key odors such as menthol, lemon, lilac and leather

were most predictive of whether or not they would develop the

memory-robbing disease.

In an interview, Devanand, who also works at the New York State

Psychiatric Institute, explained that researchers have known for years

that smell memory is one of the first things to go in someone with early

Alzheimer's disease. People can detect smells perfectly well, he said,

but cannot identify them.

" You have to recognize (the smell) against your memory of smells of that

type, " Devanand told Reuters Health. " And that's where the problem is. "

Devanand and his colleagues asked 150 people with mild memory

impairments and 63 others without impairments to identify 40 different

smells. The researchers followed them for an average of five years,

noting who developed Alzheimer's disease.

The researchers then looked at which smell memories were most often

impaired in people with early Alzheimer's disease, and reviewed smell

data from people known to have Alzheimer's disease, to pick which smells

were most predictive of a person's chance of getting the disease.

Ultimately, Devanand and his team narrowed the list of 40 smells down to

10, which also included clove, strawberry, pineapple, smoke, soap and

natural gas. " These 10 items predicted as well or better than the entire

40-item test, " Devanand said, and a shorter list takes much less time to

complete.

The smell test detected Alzheimer's disease better than brain imaging

and genetic testing did, and worked just as well as an extensive memory

test that can be very frustrating and unpleasant, Devanand noted.

The next step, he said, is to continue testing the smell test to make

sure it can truly diagnose the disease. He predicted that it will likely

be a " couple of years " before it is available to people with mild memory

problems.

Devanand and his team presented the findings Monday at the American

College of Neuropsychopharmacology annual meeting in San , Puerto

Rico.

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org