New Test for Consciousness in Comatose Patients

The Coma Science Group (CRCyclotron, University of Liège /Liège University Hospital), led by Dr Steven Laureys, has developed, along with its partners in London, Ontario, (Canada) and Cambridge (England), a portable test which will permit a simpler and less expensive diagnosis of ‘vegetative’ patients who still have consciousness, despite the fact that they do not have the means to express it. The researchers’ conclusions are published this week in The Lancet (1), one of the most influential medical journals.

The desire to develop this simple test of consciousness, at the patient’s bedside, follows on from previous research carried out by the Coma Science Group. Professor Steven Laureys and his colleagues had in effect already demonstrated, in 2009, that 40% of so-called ‘vegetative’ patients had been badly diagnosed and that in reality they retained a certain degree of consciousness (2). Following on from this study Laureys’ team at the University Hospital of Liège, on the recommendation of the Federal Health Service, was able to prescribe the compulsory use of a specially designed scale of consciousness (the coma recovery scale), now used in every coma specialist centre in Belgium.

In 2010 the Coma Science Group researchers and their colleagues at Cambridge (England) made another fundamental breakthrough in showing that it was possible to communicate with ‘vegetative’ patients through the means of scanners whose technology was based on functional magnetic resonance imaging (fMRI) (3). Classically, the clinical evaluation of coma always proceeded via a muscular response to a stimulus. This study showed that, thanks to fMRI, a doctor could detect traces of consciousness and even communicate with so-called ‘vegetative’ patients due to the fact that they mentally responded in an appropriate manner to a task suggested by the evaluator (2). Scientifically revolutionary, using functional magnetic resonance imaging in the evaluation of comas is nevertheless very expensive, and not every hospital is equipped with or has access to it.

The new test described this week in The Lancet should change this situation. “As doctors, we as a rule ask the patient to respond to a simple command, such as ‘pinch my hand,’ to assure us that the patient is conscious. When we obtain a response, everything is fine, but if we cannot detect a response that does not necessarily mean to say that the patient is unconscious. Sometimes he or she cannot move because injuries have affected the nerves, the spinal cord or the brain,” explains Dr Laureys. “With our new test, we also ask patients to move their hand or their foot, but we no longer have confidence in the muscular response. We measure the activity of the motor cortex directly using electroencephalography (EEG), a cheaper method which is widespread throughout the hospital centres.”

“That means that this portable test can be carried out in every health care centre and even at home!” states Camille Chatelle, a neuropsychologist and one of the new study’s co-authors.


(1) “Bedside detection of awareness in the vegetative state”, Cruse D, Cennu S, Chatelle C, Bekinschtein TA, Fernández-Espejo D, Pickard JD, Laureys S, Owen AM is published in The Lancet, XX October 2011 suite référence

(2) “Diagnostic accuracy of the vegetative and minimally conscious state: clinical consensus versus standardized neurobehavioral assessment.” Schnakers C, Vanhaudenhuyse A, Giacino J, Ventura M, Boly M, Majerus S, Moonen G, Laureys S, BMC Neurology (2009) 9:35.

(3) “Willful modulation of brain activity in disorders of consciousness”, Vanhaudenhuyse A & Monti MM, Coleman MR, Boly M, Pickard JD, Tshibanda JF, Owen AM, Laureys S, New England Journal of Medicine (2010) 362 (7) :579-89.

Notes on the study

These studies are the result of joint work carried out by the teams at Liège, the London University of Western Ontario (Professor AM Owen, Doctors D Cruse & D Fernández-Espejo) and Cambridge, England (Pr JD Pickard & Drs S Cennu & TA Bekinschtein). The objective of the Liège Coma Science Group’s multidisciplinary teams (Neurology, Neuroradiology, Psychology, Anaesthesia, Intensive care, Neurosurgery and Rehabilitation Medicine at the Liège University Hospital Centre, as well as engineers, physicists and mathematicians from the ULg’s Cyclotron Research Centre and guest scientists from throughout Europe) is to improve medical healthcare and better understand the altered states of consciousness, such as coma, the “persistent vegetative state” (now called unresponsive wakefulness syndrome), the minimally conscious state and locked in syndrome, which follow a brain injury. Patients from the length and breadth of Europe are sent to Liège for a short hospital stay, with the aim of establishing diagnosis, prognosis and therapeutics. The experimental techniques include the tools of state of the art neuroimaging, neuropsychological studies carried out on a large population of the patients, as well as studies carried out on healthy volunteers under anaesthesia or hypnosis. The ensemble of the results of the studies are then related back to clinical reality, thus enabling a better understanding of the pathologies and the rehabilitation strategies.

The Coma Science Group is funded by the American Foundations James S. McDonnell and Mind Science, the European Commission (Decoder, Mindbridge, Discos & COST), the Fonds National de la Recherche Scientifique Belge (FNRS), the SPF Santé Publique, the Action de Recherches Concertée, the University of Liège and the Liège University Hospital and the Léon Fredericq Foundation.

Source: University of Liège press release

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