Simple Test May Diagnose Alzheimer's Early: Sniffing Peanut Butter
A graduate student at the University of Florida's McKnight Brain Institute Center for Smell and Taste, Jennifer Stamps, designed a very simple test to support the determination of Alzheimer's disease (AD) - a smell test involving peanut butter. If further experimentation is successful, the smell test just might prove to be the holy grail for an inexpensive preliminary diagnostic tool for AD.
Loss of the sense of smell is one of the early symptoms of AD, yet Stamps noticed that none of the tests used to diagnose Alzheimer's were related to the sense of smell. She set up a simple test using peanut butter for the smell test, as peanut butter has pure olfactory sensations, as opposed to other foods which might also deliver physical sensations.
In the study, patients who came to the UF neurology clinic for diagnostic testing were given a smell test in addition to the other tests. Using a container of 14 grams (approximately 1 tablespoon) of peanut butter and a metric ruler, subjects were asked to close their eyes and hold one nostril closed. The clinician then held the peanut butter next to the subject's open nostril while the patient breathed normally and, as the clinician moved the peanut butter, centimeter by centimeter further away from the nostril, the subject signalled when he or she could smell the peanut butter. Scores were recorded when the subject stopped signalling.
Smell sensitivity indeed corresponded with other Alzheimer's tests administered by the researchers, but the most revelatory finding was that the subjects in the early stages of AD were less sensitive to the peanut butter smell in the left nostril than the right nostril - on average, 10 centimeters less sensitive.
This was a small study and further research is necessary before this or any other smell test might be used as a preliminary diagnostic test, but the UF researchers see much promise.
Please don't draw conclusions from any smell tests you conduct at home; you might easily frighten yourself unnecessarily. There are other diagnoses for the inability to smell, like a sinus blockage, for one.