Coma : how do you know ?

beerkoff1/Epictura

Published the 23.10.2017 at 15h58

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Keywords :

comaTrouble of the conscienceTest prognostic

According to a study by the Inserm study in 127 patients in coma, between the ages of 17 to 80 years of age, the change of the heartbeat in response to a sound stimulation is a good indicator of the state of consciousness, coma, deep. This is according to a press release from the nserm published today.

A simple test and supplementary

The test is to listen to sound sequences initially repetitive and with so rare and random, variations. During these disturbances, the researchers can determine if the rhythm of the heartbeat is altered, reflecting an awareness of the surrounding noise and a better prognosis of coma.

This is demonstrated by Jacobo Sitt, a researcher at Inserm, and his team based at the institute of the brain and the spinal cord at the Pitié-Salpêtrière hospital, AP-HP, in an article published in the Annals of Neurology. This review is easy to achieve, is complementary to the already existing tests and allows a diagnosis predictive of more end, useful to both physicians and families.

Coma : prognostic importance of the state of consciousness

The study of disorders of consciousness in coma distinguishes a schematic representation of the vegetative state, in which the patient is awake but not conscious, minimally conscious state, which corresponds to a certain degree of consciousness. Distinguish between these two states is very important to establish a prognosis on the future of the patient, to inform the relatives and therefore to implement a suitable treatment.

All the tools developed so far to determine the state of consciousness, such as the electroencephalogram (EEG), functional MRI or the PET scan, focusing on the functioning of the brain. These tools require either a heavy equipment or complex analysis.

Inserm researchers have used an innovative approach : the exploration of the interaction between the heart and the brain. Previous studies had highlighted that the process “unconscious” of the neuro-vegetative system, such as breathing or the beating of the heart, could be modulated by cognitive processes to be aware of. The perception of an external stimulus, hearing for example, could result in an effect on the heart activity, and so much the more easily as the subject is aware.

A promising study

By studying the data of 127 patients in vegetative state or minimal consciousness, the researchers found that the cardiac cycles were indeed modulated by the auditory stimulus only in patients aware or minimally aware.

They also showed that these results were complementary to the results obtained in the EEG. The combination of these two tests (test of the heart, and EEG) improving significantly the predictive performance of the state of consciousness of a patient.

These results open new perspectives in the framework of a global approach to assess the state of consciousness of patients in coma. The researchers now want to extend the framework to other physiological signals modulated by conscious processes such as respiration, or dilatation of the pupils, to develop a comprehensive tool to better assess the state of consciousness at the patient’s bed.