The ability to detect odors, measured in a simple and inexpensive “smell test,” predicts “with remarkable precision” the recovery of patients who have suffered a serious brain injury, helping doctors diagnose them and determine the best treatment.
If an unconscious and brain-damaged person responds to the odor through a slight change in their nasal airflow pattern, they are likely to regain consciousness.
This concludes a study by researchers from the Weizmann Institute (WI) and the Loewenstein Rehabilitation Hospital (LRH), both in Israel together with the University of Cambridge (CU), in the United Kingdom, (www.nature.com/articles/s41586 -020-2245-5).
Based on their findings, 100% of patients with brain injury and unconsciousness who reacted to an olfactory test developed by the researchers regained consciousness during the four-year study period.
“The precision of this test is remarkable: I hope it will help treat patients with severe brain injuries worldwide,” says Anat Arzi, a researcher at the UC and WI Department of Psychology, who led the research, along with Professor Noam Sobel also from WI and Dr. Yaron Sacher from LRH.
The oldest part of the brain
These scientists believe that this simple and inexpensive test can help doctors accurately diagnose and determine treatment plans based on each patient’s degree of brain injury.
They conclude that their finding highlights the key role of the sense of smell in the organization of the human brain.
“The olfactory system is the oldest part of the brain, and its integrity provides an accurate measure of the overall integrity of the brain,” they say.
They explain that our sense of smell is a very basic mechanism and is based on structures deep within the brain.
“The brain automatically changes the way we smell in response to different smells. When an unpleasant one presents itself, we automatically take shorter, shallower breaths. In healthy people, the olfactory response occurs in both waking and dream states of consciousness, “they explain.
“After severe brain injury, it is often difficult to determine whether the person is conscious or unconscious, and current diagnostic tests, based on their response to visual and auditory stimuli as well as pain, among others, can lead to an incorrect diagnosis up to 40% percent of cases, ”says Arzi.
A patient in a ‘minimally conscious’ state (with a minimal or unstable consciousness) differs from one in a ‘vegetative state’ (with no evidence that he is aware of himself or his environment), and his evolutions, future outcomes, and strategies also differ. to treat them, according to the researchers.
“The wrong diagnosis can be critical, since it can influence the decision to disconnect a patient from life support machines and the fact of not prescribing pain relievers that they may be needing,” says the scientist.
The “test of consciousness” developed by these researchers is based on the principle that our nasal airflow changes in response to odor.
Measuring smell to spy on the brain
The study included 43 brain-injured patients, under whose noses jars containing various odors were briefly placed, including a pleasant shampoo aroma, an unpleasant rotten fish odor or no odor.
At the same time, the scientists measured the volume of air inhaled through the nose in response to odors, using a small tube called a nasal cannula.
In each session each bottle was presented to the patient ten times in random order and each patient participated in several sessions.
By measuring the olfactory response, the researchers were able to measure the function of deep brain structures in those patients with severe brain injury.
“Surprisingly, all the patients classified as ‘vegetative state’ who responded to the smell test, regained consciousness (even if only minimal) a time later,” according to Arzi.
And the olfactory response not only predicted who would regain consciousness, but also who would survive for at least three years, with around 92% accuracy, “he says.
“The fact that this olfactory test is simple, potentially inexpensive and that it can be performed at the bedside of patients without the need to move them or complicated machinery, makes it very advantageous,” concludes Arzi.
(June 23, 2020, EFE / REPORTAJES / PracticaEspañol)
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solo es correcto "periodo".
solo es correcto "período".
tanto "periodo" como "período" son correctos.
"estar de acuerdo".
"de ningún modo".
estás aspirando aire.
te estás aguantando la respiración.
estás despidiendo o exhalando aire.
a algo que no tiene olor.
al sentido del olfato.
solo a algo que huele bien.