Researchers sniff out an indicator for Alzheimer’s

The nose is the newest clue to Alzheimer’s disease. A simple scent test could determine whether a case of mild, short-term memory loss will develop into the progressive neurological disorder.

Specific scents are the key.

Strawberry, smoke, soap, menthol, clove, pineapple, natural gas, lilac, lemon and leather: People with mild cognitive impairment who cannot identify these scents will develop Alzheimer’s disease, according to research from the American College of Neuropsychopharmacology.

Based at Vanderbilt University, the 700-member research group released the findings yesterday during an annual meeting.

The “10-smell test,” which takes only a few minutes, is as accurate a predictor for the disease as a more complex memory test or an expensive magnetic resonance imaging that measures brain volume, researchers say.

“Early diagnosis of Alzheimer’s disease is critical for patients and their families to receive the most beneficial treatment and medications,” said study author Dr. D.P. Devanand, professor of psychology and neurology at Columbia University and director of the Memory Disorders Center at the New York State Psychiatric Institute.

Dr. Devanand offered the odor-identification test to 150 patients with mild cognitive impairment twice in one year. Sixty-three healthy seniors were tested once. He followed up on the groups’ progress after five years.

His research found that the 10 scents “proved to be the best predictors for Alzheimer’s disease.”

“Narrowing the list of odors can potentially expedite screening and help with early diagnosis,” Dr. Devanand said.

He added that nerve pathways in the brain that perceive and recognize that odors are among the first affected in Alzheimer’s patients.

“This research is very promising. It presents a test that is both low-tech and noninvasive, plus it has some good basic science behind it that makes sense,” said Dr. Gary Small, professor with the Neuropsychiatric Institute at the University of California at Los Angeles and director of its Center on Aging.

“These patients in question can smell things. But they can’t identify what they are smelling. That’s significant,” Dr. Small said, noting that his research measuring the progress of Alzheimer’s in the brain through scans and chemical markers confirms that olfactory processes can be affected in patients with the disease.

“This test involves 10 smells, not 40. It doesn’t take a lot of time. For a physician, that could prove both practical and inexpensive,” he said.

The smell test is one piece of the Alzheimer’s puzzle, and of potential interest to the large population of aging baby boomers.

First identified in 1906, the fatal and degenerative brain disease affects 4.5 million Americans. The number has doubled since 1980 and could quadruple by 2050, according to the Chicago-based Alzheimer’s Association.

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