Brain imaging allows a vegetative patient to communicate
According to new research, some of the people considered to be in a vegetative state may be more aware than previously thought and even be able to communicate. One of the patients in the study, published today in the New England Journal of Medicine (NEJM), was able to correctly answer a series of yes or no questions, his answers being interpreted through brain imaging.
The research highlights how difficult it can be to diagnose people in this state and how new technologies could help. It also opens up new avenues for communication with those believed to be lost to the waking world and raises a number of ethical and philosophical questions about the definition of consciousness and how to evaluate it.
In the current study, patients diagnosed as vegetative or minimally conscious were asked to imagine themselves playing tennis, or walking the streets of a family town or home. In healthy people, each of these tasks activates a characteristic part of the brain, allowing scientists to determine from a brain scan which of the two situations the person is visualizing.
The researchers observed that five of the 54 patients who were supposedly in a vegetative state were able to voluntarily control their brain activity, suggesting that, although rare, some people with few or no external signs of consciousness have measurable symptoms of consciousness. All five patients had suffered brain damage as a result of head trauma rather than lack of oxygen, confirming that this group has more promising prospects for recovery.
The team went on to show that one of the patient patients, a 22-year-old who had been diagnosed with a vegetative state after a car accident five years earlier, could use this imaging task to communicate. The patient was asked to imagine playing tennis if the answer to a question was affirmative, and to imagine his home if the answer was negative. The patient was able to answer five of the six questions and answered all of them correctly.
Source: Technology Review