Have you ever been in the act of conducting training and suddenly realize that the trainees collectively appear to be in a vegetative state? Hey. We’ve all been there. Your stomach knots up, your mind races, and you get a mental image of yourself running out of the room screaming. As if even that would wake them up!
Well, don’t give in. In the 9-20-2009 online edition of Nature Neuroscience, scientists from the University of Cambridge (UK) and the Institute of Cognitive Neurology (Argentina) reported findings indicating that some people who appear to be in vegetative or minimally conscious states can still learn – despite lacking the ability to report their responses.
Scientific American’s Katherine Harmon explains the importance of this new study: “In patients who have survived severe brain damage, judging the level of actual awareness has proved a difficult process. And the prognosis can sometimes mean the difference between life and death.”
Until now, doctors have used a battery of tests and subjective observations to determine whether a patient’s movements are meaningful, in effect whether there is any evidence of perception or consciousness. Now, they may have an objective way of determining whether a conscious state is present. And, it’s based on research done a couple hundred years ago by our old buddy, Ivan Pavlov, he of the salivating canines.
In the study conducted in Britain and Argentina, doctors sounded a tone, “waited” 500 milliseconds, and then administered a light puff of air to a patient’s eye. Of course, the puff of air could cause a patient in a vegetative or minimally conscious state to blink or flinch. You can train even snails to react to the very same kind of puff. But, what the researchers found is that after 30 minutes of repeated tone-puff-blink reactions, some patients – presumably those not in a truly vegetative state – would begin to blink after hearing the tone – but without being administered the puff of air. The investigators believe that you need conscious processing to obtain that no-puff reaction and, backing them up, control subjects who had been under strong anesthesia did not “learn” the blink response.
The “puff of air” research, being highly controlled and conducted in different settings, gives credence to previous, more methodologically limited, research that focused on a simple pairing of verbal stimuli and electrochemical brain activity. The subjects in this earlier study had all been diagnosed as being in vegetative states. While recording cortical activity, researchers asked each patient to imagine playing a strenuous game of tennis. For many of the patients, nothing happened. For others, some brain activity was noted in premotor areas, a possible indication of misdiagnosis of their states. But, with the “puff of air” study in hand, researchers are more willing to give credence to the “tennis” study because they now have direct and high-controlled evidence of learning. And, perhaps much more importantly, doctors have a more objective way of measuring whether consciousness exists.
Returning to the stony-faced trainees in your program: Perhaps if you hadn’t inflicted brain damage on them in the first place…
Original references for any studies, books or articles cited by the Brain and Behavior Blogger can be obtained by contact with his very dear friend, Dr. Rob Snyder (r.snyder@tier1performance.com), an organizational psychologist with a severe neuroscience-research reading habit.
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