“Studies have confirmed that the dysfunction of the olfactory identification would make it possible to distinguish cognitively healthy people from people who have a moderate cognitive deficit or who have Alzheimer’s disease”, summarized Professor Charles Ramassamy, of the National Institute. of scientific research.
In a first study published in 2013, scientists at the University of Florida measured how far their subjects could detect a container of peanut butter with each nostril.
In those who were probably suffering from Alzheimer’s disease, they had to approach the container on average ten centimeters closer to the left nostril than to the right nostril.
Then, in 2020, Chinese researchers found that odor detection scores declined in subjects with cognitive loss or Alzheimer’s disease.
The proportion of subjects with smell dysfunction was particularly high among those with Alzheimer’s disease.
“The objective is to go and see upstream of the disease, until when we can go back in time to find this dysfunction, which could be predictive of the disease a few years before, five or ten years before the disease. Alzheimer’s disease, ”said Professor Ramassamy.
If it should be kept in mind that the loss of smell is not specific to Alzheimer’s disease, as the current coronavirus pandemic demonstrates, this could represent an “added value” to the tests that a doctor administers to his patient, especially if the latter is close to the stage of the disease, he added.
Only 11% of patients who have moderate cognitive problems, but who do not have olfactory dysfunction, will progress to Alzheimer’s disease.
The olfactory dysfunctions are linked to the alterations observed in the brains of patients with Alzheimer’s disease.
Imaging studies would show, for example, that the brains of patients in whom Alzheimer’s disease has not yet been diagnosed, but who have olfactory dysfunction, have changes similar to those in the brains of patients with Alzheimer’s disease. ‘Alzheimer’s.
“The mechanisms in the brain could start ten, twenty, thirty years before the first symptoms,” concluded Dr. Ramassamy. The more early markers we can identify over time, the more we can turn on a little red light that will tell us to be careful and we can do additional tests to go further. “