The idea of using peanut butter came to a graduate student, Jennifer Stamps, who while working in the department of neurology at the University of Florida, noticed that patients suspected for Alzheimer's were not being tested for their sense of smell. The idea behind testing patients for their smelling ability came from the fact that the first cranial nerve in the brain has an olfactory function, or in simple terms carries the smell from the nasal cavity to the brain and is one of the first nerves to be affected as Alzheimer's disease progresses. Naturally, testing patients for their smelling ability was theoretically, the simplest method of screening suspected patients.
Simple Peanut Butter smelling test for Alzheimer's
Image credit: University of Florida
Once this was established, Jennifer had to just come up with a test that was not expensive to carry out and still be effective. She chose peanut butter for its easy availability (in the US) but any other substance that is a 'pure odorant' i.e. detected by the olfactory sense alone would have done. A pilot study was organised where patients suspected of having Alzheimer's were enrolled and subjected to a simple test to measure the distance from where the blindfolded patient could smell the tablespoon of peanut butter with one nostril . After a 90 second delay the test was repeated for the second nostril and the distance again measured.
Although, all tests were carried out without knowing the diagnosis for these patients, it was later found that patients whose diagnosis for Alzheimer's was confirmed using other tests, also showed smelling impairment with the left nostril. The same patient could smell peanut butter even upto 10 cms further away, using his/ her right nostril but consistently failed to smell like the rest of the patients with their left nostrils. Such a test will be extremely useful in clinics that do not have sophisticated modern equipment and can also be performed by patients at home to track progression of such an impairment over a period of time.