Olfactory identification tests are getting some press for their possible use as an Alzheimer’s predictor. But, a new article says it’s too soon.
Alzheimer’s is a progressive neurological degeneration causing loss of brain function. It is the most common cause of dementia particularly in old age. The number of people diagnosed with Alzheimer’s is expected to double every 20 years through 2040.
A new test for Alzheimer’s would be welcome, but it’s just too early. “Smell tests have been touted as a possible way of predicting Alzheimer’s dementia because of a reported association with decreased sense of smell. Our team set out to determine whether these beliefs are based on existing high-quality evidence,” said Gordon Sun, MD, a general otolaryngologist and Robert Wood Johnson Foundation/US Department of Veterans Affairs Clinical Scholar at the University of Michigan, Ann Arbor.
They reviewed 1200 studies and found only 30 that met inclusion criteria. While the team found evidence that loss of smell is associated with Alzheimer’s, there’s simply not enough evidence to conclude that loss of smell is a predictor by itself. Researchers note that the sense of smell can be affected by too many other things leaving many possible explanations for the sensory loss.
“A nonspecific association between poor smell function and Alzheimer’s dementia is not the same as actually being able to use a smell test to predict Alzheimer’s. Unfortunately, this misinterpretation of the research has led to the promotion of these tests by the medical and public figures like Dr. Oz. This study helps set the record straight about where the evidence currently stands,” concluded Sun.
Source: MedicalNewsToday, The Laryngoscope