Poor Sense of Smell May be Alzheimer's
(Chicago, AP, 7/3/07)

In a study funded by the National Institute on Aging and the Illinois Department of Health, Robert Wilson of Chicago's Rush University Medical Center, and team, had 600 adults identify 12 common odors, including foods, spices, rose, soap, paint thinner, gasoline and smoke. The researchers presented 4 choices, both aloud and in text, for each smell. The investigators then gave the participants 21 cognitive tests annually for five years and found that subjects who had originally misidentified more than three odors had a 50% greater risk of mental decline than those making no more than one error. In addition, those having difficulty identifying scents were likelier to progress from mild impairment to Alzheimer's. These results support previous research showing that the microscopic lesions indicative of Alzheimer's disease first appear in a brain region related to the sense of smell.  The findings suggest that olfactory tests may be useful in the early diagnosis of Alzheimer's.

(Archives of General Psychiatry, July 2007)