Wanderings of the mind and signs of consciousness
Detecting residual consciousness in patients that are severely brain-damaged represents a major challenge from a medical and ethical point of view. It is also a difficult task given the risk of misdiagnosis which is a constant threat to medical professionals. In collaboration with the Massachusetts Institute of Technology, the Coma Science Group of the University of Liege and University Hospital of Liege recently showed that resting state functional MRI scanning is an efficient tool for establishing the level of consciousness of brain-damaged patients who are incapable to communicate.
The minimally conscious state was demonstrated in 2002 by Joseph Giacino. It describes patients who are capable of following simple instructions in a “reproducible” way but still have fluctuating consciousness with regard to their environment. For example, they may execute voluntary movements from time to time, smile at family members or follow a moving object with their eyes; nevertheless, they will never succeed in communicating their thoughts. Patients in a vegetative/non-responsive state, on the other hand, have no consciousness of the external world and can only make involuntary reflex movements. As such, the results of clinical examination of the VS/UWS patients often remain clouded in uncertainty as discussed above.
Complementary use of Functional Magnetic Resonance Imaging (fMRI and/or Positron Emission Tomography) has made it possible to reduce the number of misdiagnoses around twenty per cent. In this type of examination, patients are usually asked to follow simple instructions during which their brain activity is recorded. But these tools are costly, relatively inaccessible and non-portable, very sensitive to patients’ movements while in the scanner and are hindered by the time-scale required to acquire data.
(1) Schnakers, C., Vanhaudenhuyse, A., Giacino, J. T., Ventura, M., Boly, M., Majerus, S., Moonen, G., & Laureys, S. (2009). Diagnostic accuracy of the vegetative and minimally conscious state: clinical consensus versus standardized neurobehavioral assessment. BMC Neurol, 9, 35.