Interaction Between Brain and Heart May be New Indicator of State of Consciousness

How do we know whether a patient is conscious when he or she is unable to communicate? According to an Inserm study conducted in 127 patients aged 17 to 80, changes in heartbeat in response to sound stimulation is a good indicator of state of consciousness. This is what Inserm researcher Jacobo Sitt and his team, based at the Brain & Spine Institute (ICM) at Pitié-Salpêtrière Hospital, AP-HP, demonstrate in an article published in Annals of neurology. This easy-to-perform examination complements the existing tests and enables finer predictive diagnosis, useful for both doctors and the patient's loved ones. The study of consciousness disorders distinguishes the vegetative state, in which the patient is awake but not conscious, from the minimal state of consciousness, which involves a certain degree of consciousness. Distinguishing between these states is very important in order to establish a prognosis on the patient's neurological outcome, inform the patient's loved ones, and implement suitable treatment. The tools developed up until now to determine state of consciousness, such as the electroencephalogram (EEG), functional MRI or PET scan, all concentrate on the brain. These methods require either heavy equipment or complex analysis.