The light's on, but is anybody home?

An extraordinary brain study concludes that a woman in a vegetative state is aware of herself. It's a dangerous claim that could throw families and physicians into turmoil.

Editor's note: This marks the debut of "Mind Reader," by neurologist Robert Burton, a new Salon feature exploring the galaxy of the brain.

By Robert Burton

Read more: Neurology, Brains, Terri Schiavo, Life, Mind Reader

Sept. 25, 2007 | In a recent article in the Archives of Neurology, a team of British and Belgian neuroscientists describe a clinically unconscious accident victim who can, on command, imagine herself playing tennis and walking around her house. By showing that her functional brain imaging studies (fMRI) are indistinguishable from those of healthy volunteers performing the same mental tasks, the researchers claim that the young woman's fMRI "confirmed beyond any doubt that she was consciously aware of herself and her surroundings, and was willfully following instructions given to her, despite her diagnosis of a vegetative state."

Their extraordinary conclusions are beyond provocative; they raise profound questions about the very notion of consciousness. What's more, they could throw thousands of families and doctors into utter turmoil. As with the Terri Schiavo controversy, patient advocacy groups, self-serving lawyers and politicians with personal agendas could use the study's stamp of certainty as a given.

Yet the study's conclusions are not beyond a doubt. There are plenty of questions about whether this young woman is conscious and capable of choice.

Let's briefly look at the study. In mid-2005, a 23-year-old woman sustained massive head injuries in an auto accident. Following multiple brain surgeries and five months of rehabilitation attempts, she remained unresponsive. According to her treating physicians, she could open her eyes but could not respond to any commands; she could not voluntarily look in the direction of a voice; there was no evidence of orientation or emotional response. They determined that she was in a permanent vegetative state -- a neurological categorization of patients who emerge from coma, appear to be awake, but show no signs of awareness of self or environment.

Before the recent advances in functional brain imaging, most neurologists, based upon their bedside observations and brain wave studies, would have agreed that the woman, though "awake," was extremely unlikely to have a significant private mental life -- either in terms of personal awareness or willful mental activity. (This failure to differentiate between awake and aware was a major feature of the Schiavo affair.) But new tools bring new opportunities; her doctors wondered if the fMRI could provide additional understanding of the clinically unresponsive brain. What if the fMRI could demonstrate residual consciousness and self-awareness, perhaps even the ability to respond to commands?

Their proposed study was quite simple. While inside an fMRI scanner, the unresponsive woman was asked by the researchers to perform three mental tests: relax, imagine playing tennis, and imagine walking around the various rooms in her home. The tasks were chosen because of their ability to activate different areas of the brain. Imagining playing tennis would light up the supplementary motor area, a region involved in imagining as well as performing coordinated movements. In contrast, imagining moving from room to room in a house activated those regions, such as the posterior parietal lobe, that contribute to imaginary or real spatial navigation.

At first glance, the results are startling. The patient was able to activate the same general brain regions as conscious volunteers serving as controls in the test; according to the authors, the images were statistically indistinguishable.

But are the authors' conclusions justified? Should we accept that the patient really was consciously aware and able "to understand instructions, carry out different mental tasks, and exhibit willed voluntary behavior in the absence of any overt action."

Traditionally, consciousness has been considered a subjective and private experience. Unless we subscribe to Las Vegas versions of telepathy, we are dependent upon what a person's mind tells us about what that mind is doing. We ask someone what they are thinking or how they are feeling; if they don't answer, we are left guessing at the meaning of sighs, grunts and bits of body language and gesture.

Are we to now believe that an fMRI can tell us the level and nature of a patient's consciousness even when the patient can't respond? Putting aside for a moment the very considerable questions of fMRI methodology, and interpretation, are we ready to accept technology as the final word in assessing mental states?

This is not simply an academic question applicable to a single patient. Tens of thousands of patients in a persistent vegetative state linger in long-term care facilities. Others remain under the radar, being cared for at home by their families. The estimated annual cost of medical treatment for them is between $1 billion and $7 billion a year. Once larger numbers of patients are evaluated via fMRI, it is quite likely that we will find others with similar degrees of activation on a variety of mental tasks. Family members will be asked to understand, interpret and act on the scan reports. I cannot imagine a worse medical nightmare than being told that a clinically unconscious spouse or child has been shown on fMRI to have an active imagination and substantial self-awareness, especially when the findings don't alter the grim prognosis or substantiate the value of greater rehabilitative efforts. Before putting a family through such agonizing dilemmas, we neurologists should be reasonably certain that what the fMRI shows does correspond to actual mental states in the seemingly unconscious.

But how could we make such a determination? How can you objectively confirm what is, at bottom, a subjective experience?

Stymied, I decided to take a step back and review what the fMRI has shown in other states of diminished consciousness. But to understand what we see on such scans, we need to first look at how the brain processes information. For a quick example, consider how a visual image is formed and projected into consciousness.

Your retina detects a yellow-and-black fluttering. The information is sent to the primary visual cortex. Specialized collections of neurons (modules) process different aspects of vision, such as the detection of vertical or horizontal motion, lines and edges, determination of color. The output of these modules then flows into higher order networks -- first within the visual association areas, and then into more widely distributed circuitry for non-visual elements, such as the remembrance of seeing a similar pattern hovering over a mountain lake, a trip to a natural science museum with your grandfather, the cover of a book on chaos theory, a scary scene from "Silence of the Lambs." Finally, through mechanisms both utterly mysterious and widely distributed throughout the brain, this unconsciously constructed perception is delivered into awareness; you suddenly "see" a monarch butterfly floating in front of you.

If we were to watch this process on fMRI, we would see activation of the primary visual cortex, secondary visual association areas, as well as more widely distributed non-visual areas that contribute to your understanding of and feelings toward a butterfly. But we would not see the image's transition from unconscious to conscious perception. Consciousness isn't generated by a specific brain area that can be directly visualized. The fMRI can show us the precursors of a perception: It cannot tell us if the person is actually aware of that perception.

Next page: At best, an fMRI is the equivalent of an aerial photograph of a house