Besides the fact that the work carried out by the Italian, American and Belgian researchers confirms the prediction of the Information Integration Theory proposed by Giulio Tononi, it could well lead to an approach that may soon be used in hospitals which, contrary to almost all the examinations currently practiced to determine the degree of consciousness in severely brain-damaged individuals, doesn’t require the patient’s collaboration.  “During clinical tests, we may not receive a response from the patient, not because they are completely unconscious, but because they have become aphasic and don’t understand what is requested of them (for instance, closing their hand), or because they are paralysed”, adds Steven Laureys.

PCI has no intention of going it alone, but it could fulfil a crucial role in the range of means implemented to “track down consciousness”. Traditionally, in severely brain-damaged patients, the neurologist’s diagnosis was almost exclusively based on the examination of the subject’s motor responses, in particular in response to an order (“Squeeze my hand”, "Look down”, etc.). As we pointed out, diagnostic errors using this approach are legion.

Defining standardised clinical tools is likely to reduce their number. The Coma Recovery Scale-Revised – CRS-R, developed in the United States and validated in French and Dutch by Steven Laureys and Caroline Schnakers, pursues this objective.

And diagnosis could be further honed through the use of functional imaging techniques, which pleads in favour of the design of an inexpensive and easy-to-use tool. A great deal of work is being done in this area, especially concerning the technique of auditory and cognitive evoked potentials. The use of functional magnetic resonance imaging (fMRI) and positron emission tomography (PET scan) during the "state of rest" – the subject is awake, eyes closed, and isn’t performing any task – is also very promising. This is equally the case for “brain-computer” interfaces where the brain’s electrical activity is measured when a patient is asked to move a limb, for instance. The study of sleep characteristics using high density electroencephalography (256 electrodes) is another possibility – the brain’s electrical activity differs very little between sleep and wakefulness in vegetative/unresponsive patients, whereas in patients in a minimally conscious state, it is similar to that observed in healthy subjects. Other avenues are also being explored. As proven by the PCI.

At the same time, neuroscientists are seeking to communicate with patients with residual consciousness (also read Conversation with a pupil). Which the researchers of the Coma Science Group and the University of Cambridge were the first to succeed in doing in 2006(5). Using real time fMRI, they managed to decipher their (positive or negative) responses to basic questions, based on the recording of brain activity in a patient wrongly declared as being in a vegetative state. They successfully repeated this experiment on other patients. For now, the emphasis is on the design of reliable, portable and inexpensive communication tools, whose use could be generalised. In principle, the solution will be based on "brain-computer" interfaces(6).

(5) A.M. Owen, M.R. Coleman, M. Boly, M.H. Davis, S. Laureys et J. Pickard, Detecting Awareness in the vegetative state, Science, Vol. 313, no 5792, p. 1402, 2006. DOI: 10.1126/science.1130197.
(6) Lulé D, Noirhomme Q, et al. Probing command following in patients with disorders of consciousness using a brain-computer interface. Clin Neurophysiol. 2013 124(1):101-6.