More mind reading: To signal yes, a patient was instructed to imagine playing tennis–the brain activity for this response is shown in orange. And he imagined walking through his house to signal no–shown in blue. His brain activity (bottom) was similar to that of a healthy person (top) performing the same task.
“This is a first case, but at least it shows that technology is challenging the boundaries based on clinical bedside examination,” says Steven Laureys, head of the coma science group at the University of Liege, in Belgium, and one of the authors of the paper. “I’m convinced that we need to adapt our standard of care and our ethical and legal framework to take account of this new technology.” The researchers did not test the other four patients who could do mental imagery, mainly because of the difficulty of carrying out the tests.
The findings open the possibility that some of these patients may be able to participate in decisions about their medical care, though a number of scientific, ethical, and legal issues will need to be discussed before taking this step. In the recent experiment, for example, scientists did not ask the patient whether he was in pain, instead sticking to factual questions with answers they could later confirm. “Before we tackle important issues such as pain, treatment, end of life, and so on, there are a lot of things we need to discuss among the medical community as whole,” says Laureys.
Exactly how aware such patients may be remains unclear. People in a minimally conscious state tend to have fluctuating levels of awareness, responding to simple questions or commands unreliably. And unlike patients with locked-in syndrome, in which a specific type of brain-stem stroke leaves the person profoundly paralyzed but largely cognitively intact, these people have clear brain damage and likely suffer severe cognitive impairments. “Even if they could say yes or no to a simple question, whether they retain enough cognitive capacity to respond to more complicated questions, we just don’t know,” says Martin Monti, a postdoctoral researcher at MRC and the lead author on the paper.
Intriguingly, before the recent experiment, medical practitioners had been unable to establish any kind of communication with the 22-year-old patient. . (Some patients, for example, can blink in response to yes or no questions.) “It must mean that somewhere his system cannot produce behavior that matches the level of cognitive functioning,” says Monti. “He clearly could understand speech, and could hear us and imagine things. These are all fairly complicated behaviors.”
Researchers are now trying to develop alternative methods of measuring brain activity in these patients. Functional MRI is expensive, time-consuming, and technically challenging–subjects must lie still during the scan, a problem for those who can’t reliably follow directions. Electroencephalography (EEG) devices, which measure the brain’s electrical activity via sensors on the surface of the scalp, are much cheaper and more portable than MRI scanners and are currently under study by Laureys and others. Researchers also aim to develop brain cognitive interfaces that will allow patients to interact with their environment, similar to those under development for severely paralyzed people.
“I think you’ll see these tools will be developed relatively quickly, because there is a sense of urgency,” says Nicholas Schiff, who is conducting similar research at Weill Cornell Medical College, in New York. “We want to know how reliably they can communicate, and whether you can give them different methods to initiate communication.”