JERUSALEM, April 29 (Xinhua) -- Israeli scientists have developed an efficient sniff test that predicts recovery from unconsciousness in brain-injured patients, Weizmann Institute of Science (WIS) said Wednesday.
Following severe brain injury, it is often difficult to determine whether the patient is conscious, as current diagnostic tests can lead to incorrect diagnosis.
In such cases, misdiagnosis can be critical as it can influence the decision of whether to disconnect patients from life support machines.
In a new study published in the journal Nature, WIS researchers and their colleagues at Israel's Loewenstein rehabilitation hospital focused on the olfactory system, whose integrity provides an accurate measure of overall brain integrity.
The new test is based on the principle that the nasal airflow changes in response to odor. For example, an unpleasant smell will lead to shorter and shallower sniffs, even during sleep.
In experiments, the researchers placed jars containing various odors under the noses of 43 brain-injured patients. This included a pleasant scent of shampoo, an unpleasant smell of rotten fish, or no odor at all.
At the same time, the team accurately measured the volume of air inhaled through the nose in response to the odors.
It was found that all patients who were classified as being in a vegetative state but responded to the sniff test later regained consciousness.
This led to the conclusion that if unconscious patients respond to smell through a slight change in their nasal airflow pattern, they are likely to regain consciousness.
The scientists believe this simple, inexpensive test can aid doctors in accurately diagnosing and determining treatment plans according to the patients' degree of brain injury. Enditem