In certain cases, the clinical diagnosis established at the bedside of a patient with severe brain lesions is erroneous. Recently, researchers at the University of Cambridge and the Coma Science Group, directed at Liège by professor Steven Laureys have perceived a residual consciousness in four patients initially declared to be in a vegetative state. They were even able to establish ‘dialogue’ with one of them, by ‘reading his thoughts’ in the profile of his cerebral activations. And this indeed incontestably raises important medical and ethical questions. The work of the British and Belgian researchers has just been published in the New England Journal of Medicine (1).

Progress in intensive care medicine has been such over recent years that it has allowed a number of patients affected by cerebral lesions to be saved, lesions which would have previously led to their deaths. Nonetheless recent successes should not mask another parallel truth: the increase in the number of patients plunged into states of altered consciousness (vegetative state, minimally conscious state) or even walled up states of consciousness, with an intact level of consciousness, but in the immobility of locked-in syndrome (LIS).

In Europe the number of new coma cases is estimated to be around 230,000 per year, of which some 30,000 develop towards states of a persistent vegetative state. A crucial question nevertheless raises its head: the difficulty of establishing a correct diagnosis – vegetative state, minimally conscious state, LIS – when the patient emerges from the period of coma, which rarely exceeds two to five weeks. According to two studies carried out at the beginning of the 1990s by Professor Keith Andrews (London) and Doctor Nancy Childs (Austin), a diagnosis drawn up ‘at the bedside’ of a patient having been subjected to serious brain lesions is mistaken one out of three times. The person can thus be declared to be in a coma or in a vegetative state, whilst s/he is in a minimally conscious state or, more exceptionally, a prisoner of locked-in syndrome.

On the 22nd of July, 2009, the journal BMC Neurology published a new study which drew similar conclusions. Carried out by Professor Steven Laureys, director of the Liège university and CHU’s Coma Science Group, by Caroline Schnakers, a researcher in the same group, and by Professor Joseph Giacino, of the New Jersey Neuroscience Institute, it involved 103 patients. It appeared that of the 44 people diagnosed in a vegetative state on the basis of the clinical consensus of the nursing team, 18 (41%) were in reality in a minimally conscious state, based on behaviour observed with the help of the Coma Recovery Scale-Revised (CRS-R), developed in the United States by Joseph Giacino’s team and validated in French  (2) and in Dutch by Caroline Schnakers and Steven Laureys (Read also "In following the scale of consciousness").