A while back, this group had a discussion on "facilitated communication", which is a way to make an unconscious person act as a human ouija board, but with a more legit sounding name.
The question is, how do you know if someone, who is in a 100% noncommunicative state, is conscious but unable to communicate? I thought of this discussion on reading an article this week in NEJM. Basically the authors used functional MRI (MRI that looks for presence of oxygen or glucose metabolism in specific areas of the brain) to see if there was brain activity when the patients were asked to visualize certain tasks. They showed that a small number of patients (about 10% in this small sample), who were thought to be fully vegetative, were actually capable of conscious communication via MRI.
"54 patients with severe brain injury, including 23 in a vegetative state and 31 in a minimally conscious state, underwent functional MRI as a means of evaluating their performance on motor and spatial imagery tasks. "...
"Before each of these imaging sessions, participants were asked a yes-or-no question (e.g., "Do you have any brothers?") and instructed to respond during the imaging session by using one type of mental imagery (either motor imagery or spatial imagery) for "yes" and the other for "no." The nature of the questions ensured that the investigators would not know the correct answers before judging the functional MRI data. Participants were asked to respond by thinking of whichever imagery corresponded to the answer that they wanted to convey. "...
"Of the 54 patients, 5 with traumatic brain injuries were able to modulate their brain activity by generating voluntary, reliable, and repeatable blood-oxygenation-level–dependent responses in predefined neuroanatomical regions when prompted to perform imagery tasks. No such responses were observed in any of the patients with nontraumatic brain injuries [in other words, oxygen deprivation or chemicals that cause diffuse damage to brain tissue, instead of localized mechanical injuries] ....Thus, in a minority of cases, patients who meet the behavioral criteria for a vegetative state have residual cognitive function and even conscious awareness."
In other words, they were able to ask the patients to think of an image or activity, depending on their answer to a question, then see in an MRI scan the brain activity that corresponded to the answer.
So much better than a "human ouija board".
This does bring up some ethical issues - like, if a person is shown to be conscious, and communciates via the functional MRI that they want their life support turned off, would that be allowed? Will they be asked that question? Is it ethical not to ask that question?
Will every person who is in a pesistant vegetative state now have to get a functional MRI?
If, shown by functional MRI to be unable to generate responses, is it ethical to continue to divert resources to these probably permanently comatose, nonsentient people, when those resources might better serve a far larger number of communicative, sentient people? If so, who pays?