Washington: Your favourite sandwich spread - peanut butter - can also be used to confirm diagnosis of early stage Alzheimer's disease!
University of Florida researchers have come up with the idea of using peanut butter to test for smell sensitivity in dementia patients.
The ability to smell is associated with the first cranial nerve and is often one of the first things to be affected in cognitive decline.
Jennifer Stamps, a graduate student in the UF McKnight Brain Institute Center for Smell andTaste, was working in Dr Kenneth Heilman's clinic, the James E Rooks distinguished professor of neurology and health psychology in the UF College of Medicine's department of neurology when she came up with the idea of using peanut butter to test patients for their sense of smell.
In the study, patients who were coming to Heilman's clinic for testing also sat down with a clinician, 14 g of peanut butter - which equals about one tablespoon - and a metric ruler. The patient closed his or her eyes and mouth and blocked one nostril.
The clinician opened the peanut butter container and held the ruler next to the open nostril while the patient breathed normally.
The clinician then moved the peanut butter up the ruler one centimetre at a time during the patient's exhale until the person could detect an odour. The distance was recorded and the procedure repeated on the other nostril after a 90-second delay.
The clinicians running the test did not know the patients' diagnoses, which were not usually confirmed until weeks after the initial clinical testing.
They found that patients in the early stages of Alzheimer's disease had a dramatic difference in detecting odour between the left and right nostril - the left nostril was impaired and did not detect the smell until it was an average of 10 centimetres closer to the nose than the right nostril had made the detection in patients with Alzheimer's disease.
This was not the case in patients with other kinds of dementia; instead, these patients had either no differences in odour detection between nostrils or the right nostril was worse at detecting odour than the left one.
Of the 24 patients tested who had mild cognitive impairment, which sometimes signals Alzheimer's disease and sometimes turns out to be something else, about 10 patients showed a left nostril impairment and 14 patients did not.
"At the moment, we can use this test to confirm diagnosis. 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," Stamps said.
The findings are published in the Journal of the Neurological Sciences.