Alzheimer’s linked to sense of smell

Difficulty in identifying common smells such as lemon, banana and cinnamon may

Difficulty in identifying common smells such as lemon, banana and cinnamon may be the first sign of Alzheimer’s disease, according to a study that could lead to scratch-and-sniff tests to determine a person’s risk for the progressive brain disorder.

Such tests could be important if scientists find ways to slow or stop Alzheimer’s and the severe memory loss associated with it. For now, there is no cure for the disease.

Researchers have long known that microscopic lesions, considered the hallmarks of Alzheimer’s, first appear in a brain region important to the sense of smell. “Strictly on the basis of anatomy, this makes sense,” said Robert Franks, an expert on odor perception and the brain at the University of Cincinnati. Franks was not involved in the new study, appearing in Monday’s Archives of General Psychiatry.

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But lead author Robert Wilson of Chicago’s Rush University Medical Centre said a diminishing sense of smell is not cause for panic. “Not all low scorers went on to have cognitive problems,” Wilson said.

Other studies have linked loss of smell to Alzheimer’s, Franks said, but this is the first to measure healthy people’s olfactory powers and follow them for five years, testing along the way for signs of mental decline. In the study, 600 people between the ages of 54 and 100 were asked to identify a dozen familiar smells: onion, lemon, cinnamon, black pepper, chocolate, rose, banana, pineapple, soap, paint thinner, gasoline and smoke.