October 11, 2013
Peanut Butter Smell Test Helps Detect Alzheimer’s Disease
[ Watch The Video: 'Peanut Butter Test' Can Help Diagnose Alzheimer's ]
Brett Smith for redOrbit.com - Your Universe Online
The Florida research team found that individuals with mild cognitive impairment, a condition that often leads to Alzheimer’s disease, had more difficulty smelling peanut butter just a short distance away from their noses than people without the condition.
Study author Jennifer Stamps said she came up with the idea while working as a graduate student in the clinic of Dr. Kenneth Heilman at the UF McKnight Brain Institute. Stamps said she noticed that patients at the clinic were not tested for their sense of smell. The omission of this test is important because smell is associated with the first cranial nerve and is frequently one of the first functions to be affected during cognitive decline.
“Dr. Heilman said, ‘If you can come up with something quick and inexpensive, we can do it,’” Stamps said.
To test her theory, volunteers from the clinic sat down with a researcher. The participants were then told to close their eyes and mouths and to block one nostril. The clinician then placed a sample of peanut butter against a ruler and under the volunteer’s one open nostril while they breathed normally. The clinician then slid the peanut butter up the ruler one centimeter at a time toward the volunteer until they detected the smell. After recording the distance from the ruler, the same procedure was repeated on the other nostril after a 90-second wait.
The clinicians administering the smell test did not know the patients’ diagnoses, which were typically not confirmed until weeks after the test was performed.
The researchers discovered that patients diagnosed as being in the early stages of Alzheimer’s disease had a significant difference in being able to smell the peanut butter between the left and right nostril. The left nostril of those diagnosed with early Alzheimer’s did not detect the odor until it was an average of 10 centimeters farther up the ruler compared to the right nostril. Patients with other kinds of dementia either showed no differences between nostrils or the right nostril was worse than the left.
Of the 24 participants with mild cognitive impairment, 10 patients showed a left nostril deficiency and 14 patients did not.
“At the moment, we can use this test to confirm diagnosis,” Stamps said. “But we plan to study patients with mild cognitive impairment to see if this test might be used to predict which patients are going to get Alzheimer’s disease.”
Until further research can refine the test, the UF clinicians said the peanut butter test will be one more method to investigate neurological function in patients with memory disorders.
“We see people with all kinds of memory disorders,” Heilman said. With many tests currently being performed at the clinic being time-consuming, costly or invasive, “this can become an important part of the evaluation process.”