I read an interesting article in the New Yorker the other day. It followed the research of neuroscientist Adrian Owen and his work on patients in vegetative states. In some patients, when he gave the verbal command to “imagine you are playing tennis,” their brain regions lit up on an fMRI indistinguishably from your average walking, talking, and recognizably conscious human being asked to perform the same task. Moreover, the patients were able to sustain this activity (so presumably the tennis imagination) for over thirty seconds suggesting some degree of focus.
The article goes on to discuss implications. It points out that Owen only found a few patients in vegetative states with this ability. Others were not at all responsive. It was a pretty good indication that the patients who were able to follow his command had some sort of retention of cognition that others did not. However, they were not diagnosed incorrectly. The question then becomes: if the criteria by which physicians diagnose vegetative states applied to these patients, do we need a better test?